Ketros Aviation Blog

Hey Presto...

2011-09-05T07:55:00.001+01:00

...Two new valves and seats. I was able to use the existing valves and cut them dowm from 14mm dia. to 11mm dia. I couldn't resist keeping the inlet valves bigger, so they're only 1mm bigger than the exhaust.

Smaller inlet valves and new seats

Sorry about the poor quality of the photo, it was taken under poor lighting conditions with my iPhone.

Next is assembly and test. This will probably take place at the weekend.

Better, but with the same old same old.

2011-08-27T17:02:00.018+01:00

I've fired it up again and its still not performing correctly. Its better, but not right. I fear the crank shaft is suffering again. I'm going to look at the cylinder heads next and perhaps make two new inlet valves and seats. I'm thinking it was a mistake to make the inlet valves so big, so I'm going to reduce their size. Too much mixture is getting into the combustion chamber and ignition is taking place far too advanced of TDC. Its OK lower down the rev range, but when the throttle is opened it tends to labour and get extremely hot.

Back together again.

2011-08-14T21:22:00.034+01:00

It's good to see it all in one piece. Assembly is by no means straight forward, and takes a considerable amount of care and patience. One of the trickiest parts is fitting the gudgeon pins. There is a PTFE pad on each end of the pins and you have to be careful not to push the first pad out of the other side of the piston. This is especially tricky when fitting the second pad as there isn't much space for them to fit between the ends of the pin and the cylinder bore.

Reassembled and...

...rarein' to go!

Another issue is the valve timing. The gears are cross helical and you have to "aim" the camshaft as you fit it because the working position is a few degrees away from where you first insert it due to the helix in the gears. I think I've got it right, but only testing will tell. I may have to advance or retard it a notch.

All the machining is finished - I think!

2011-07-18T20:04:00.000+01:00

It all just requires assembling. Easier said than done. Two new cylinders have been made with a thicker lip at the top to reduce the compression ratio. Made from Meehanite it is difficult to obtain a good finish in the bore so hand finishing with fine abrasive paper is required.

Cylinder and Piston

Finished crankshaft

I finished the crankshaft today, faced off the front end and drilled and tapped the M6 thread. Next is to start the assembly. First the primary cross helical gear has to be pressed on the rear shaft. Then the inner bearings pressed on each end, and then offered into the crank case where the conrods will be fitted.

More later, I now have a job to do for a client.

A new angle

2011-07-15T22:19:00.002+01:00

Just thought I'd take some more pictures while I had the crankshaft set up to machine the counterbalance weights - in case I need to jog my memory in the future.

Two done - One and a bit to go.

Angled faces are machined at 38 degrees.

Almost finished, all that's left to do is face off the front and drill and tap the M6 thread.

Finally, a new crankshaft.

2011-07-09T21:04:00.003+01:00

I got some infoozyazm together this weekend and have made a new crankshaft. Its not finished yet but is well on its way. To my amazement it runs perfectly true and is better than the last one. I'm going to counterbalance it this time, not as much as a single cylinder engine would be, but a bit more than "balanced".

The new crankshaft

The other thing I have to do is make two new cylinder sleeves. The originals were creating too much compression and that is what I believe was contributary to the demise of the crankshaft. I've bought some Meehanite a dense cast iron which is wear and heat resistant. I need to increase the lip thickness to raise the cylinder heads and reduce the compression ratio. The only control I have over the point of ignition is by the compression ratio. Too much and pre-ignition reduces power, increases temperature and leads to component failure as I've experienced. Too little and the engine is difficult to start, runs poorly and wastes fuel. I'll increase the lip thickness by a millimetre, if it proves to be too much I can easily remove some of the material to increase compression again.

The best day for flying.

2011-04-10T20:57:00.061+01:00

Wall to wall sunshine and light variable winds mainly from the North made today the best by far for flying this year.
Seen at Westonzoyland today:-

BAe Hawk - Nice!

We held two competitions today, the first in the morning was a fly for fun where we had to do various events, spot landing, consecutive loops, limbo circuits and touch and goes. Planned so that it can all be done in one flight. The second was a scale competition where anything resembling a scale aircraft could enter. We had to create a flight schedule which replicated the full size. I'm glad I took the Yak, but I found it a bit challenging yet enjoyable. There were two rounds and after the first round we were shown how its done by an expert accompanied by a judge/commentator who talked us through the schedule. Then we had the second round to see if there were any improvements over the first round. I failed miserably as my Yak had an engine cut for no apparent reason and I had to land prematurely. I was allowed to restart the engine, which it did instantly, (je ne se quoi?) and continue my flight. I know I didn't do so well in the second flight as I was trying too hard, my brain kept getting in the way. Won't know the results until the AGM in December.

I've made a start.

2011-03-05T17:48:00.000Z

Here we go, a new piece of stock EN16T sawn off and a flat milled all down the side. This is the location face for aligning the three centre drilled holes in each end. Once that is done it can be set up between centres in the lathe. Held in a carrier, and driven by a face plate and dog the offset journals can be machined. Here's how:-

Flat and three centres detail

Shaft held between centres

First finished journal

Here's a video of one I made earlier.

Disaster has struck!

2011-02-19T22:03:00.001Z

After making some improvements to the Ketro 120fst I tested it today and the one piece crankshaft is now a two piece crankshaft. I am amazed the whole engine didn't smash to pieces judging by the noise it made when it let go. Fortunately there is little other damage. However, I've had some thoughts. (Careful). When the throttle opens the revs increase as expected up to a point when there is a change in the sound in that the engine sounds like its suddenly working harder yet not increasing revs any further. Open the throttle more and the revs actually decrease, yet it sounds like its working even harder. Eventually the engine cuts and has become overheated. The problems are three fold:-

(1) I think this problem lies mainly in the size of the inlet valve, I have designed it too big and too much mixture is getting into the cylinders and compression reaches the point of ignition too soon before top dead centre (TDC). If it were a spark ignition engine I could control the point at which ignition takes place, but this is a glow plug engine or semi-diesel and ignition is controlled by the amount of compression. I fitted restrictors in the cylinder heads to reduce the gas flow into the combustion chamber. This has helped but there are other things to be done. I may have to look at the valve timing.
(2) I was hoping the crank case would breathe through the front bearing and to some extent it does, but its not enough so I've incorporated a breather nipple to replace one of the gearbox retaining screws. I had to drill the existing tapped hole in the crank case through to allow the pressure to release.
(3) The new crankshaft I'm going to build will have a sliding fit on the rear bearings to allow for the differing rates at which aluminium (crank case) and steel (crank shaft) expand and contract with temperature change. I think the existing set-up was trying to keep things a bit too rigid and bending of the crankshaft was taking place under high temperature resulting in an annular crack in the front crank journal, and eventually leading to its failure.

The picture says it all.

Crack detail.

You can see where the crack started to form around the outside and worked its way to the centre. Click on the photo and it should enlarge.

My first job is to retrieve the gear and bearing from the rear part of the shaft. Its probably best to drill the shaft out of the gear and do the same for the bearing. It's a good thing I've got plenty of stock material left over.

I've been busy...

2010-10-24T20:48:00.001+01:00

...Which is why I've not blogged for a while. Having just done fourteen consecutive days at work other things have gone by the bye. BUT I've finished Jims undercarriage job and is awaiting delivery.

Jims new undercarriage part

A job for Jim

2010-08-28T21:31:00.003+01:00

I've been challenged with this job for Jim. I've made a start...

A broken undercarriage pivot

A new part in the process

A fine days' flying

2010-08-22T20:28:00.003+01:00

The forecast for today has looked promising for a few days and lo and behold, it was right. Almost windless for most of the day, until mid afternoon when the wind picked up from the South.

Ians F15 Eagle

Today was a near perfect day. No one had a serious accident, Jims new jet had a bit of a kangaroo landing and scratched some paint, but no serious damage, and I lost a tail wheel from the Yak, hey-ho!

I tried out my KT120fsT this evening (before it rained) and got nowhere with it, It still stops when hot, and it certainly gets hot, too hot, but the engine isn't tightening up as its free to turn over by hand immediately after stopping. There is some pre-ignition at times and I think this may be a clue to the problem. I may have to have a closer look at the valve timing, and/or place yet another gasket under the cylinder heads. Some experimentation required.

I've had it running again...!

2010-08-15T06:59:00.003+01:00

...with more success. I turned up a pair of 0.3mm thick copper gaskets to reduce the compression ratio and tested the running characteristics again but there was still some pre-ignition going on at higher revs. Back to the machine shop then, and two more copper gaskets for reducing the compression ratio even further. Now there's hardly any pre-ignition, but I'm now finding the engine stops when it gets hot and there's hardly any compression. I know the bores were a bit rough on surface finish even after honing and this is due to the cast iron being porous. I'm tempted to make two new sleeves from a different material. That way I can build in the extra thickness required to reduce the compression ratio and do away with one gasket under each cylinder head.

Here's a short video:-

Ketro KT120fsT in action

Cornwall was a real success

2010-08-10T16:23:00.010+01:00

Everything fell into place, even the weather was spot on. We drove down early Friday morning in heavy cloud which turned into drizzle and fog over Bodmin Moor and although the fog cleared the drizzle remained on and off all the way to North Cliffs. We parked the caravan and put up the awning and waited for Geoff and Mary to arrive. They started out before us but didn't arrive until after 12:30. They'd been mooching around Redruth and Camborne all morning because they thought it may be muddy as well as wet up on the hill. But things didn't improve so they came up later.

On Saturday the weather changed. After an early shower it turned fine with 8 MPH winds from the West and broken sunshine all day, and Sunday was even better, 2 MPH winds also from the West, and near unbroken sunshine.

Me with Yak 54, photo courtesy of Geoff.

There were some nice aircraft to be seen at the show including a Stirling bomber, a deHavilland Mosquito and a Spitfire. A few jets put in an appearance with a Rookie, Kangaroo, Boomerang and an F16 flown very realistically by its skillful pilot. The electric slot was well over subscribed so the time allocation was doubled, electric gliders and slower craft first, followed by the faster EDF (Electric Ducted Fan) jets and other fast craft. That included me with the Pico-Jet.

A 180 panoramic

deHavilland Mosquito built and flown by Roger Kellow

Rogers Mozzie developed a problem during flight in that the undercarriage failed to lock down, but was able to recover from the situation and landed safely. Well done Roger.

Also impressive was a helicopter built by Kim Johns. Now helicopters leave me cold, I just can't get interested yet I feel compelled to watch in case it starts heading this way in an uncontrolled manner. But this was different. Modified and developed to accept a gas turbine, it was flown expertly by Mark Milne and performed just like a full sized helicopter. Even the sound and smell was the same. I'm told its the only one of its kind in the world - very impressive.

I've had it running...!

2010-08-01T12:48:00.004+01:00

...on both cylinders! Driving a 16" x 8" Master Airscrew propeller, and its too small. I've found it labours when it gets hot, so I think the pistons may be expanding, reducing the clearance in the bore. Its not been up to maximum revs as I'm still trying to find the best carburettor settings.
I can confirm the pistons have expanded whilst hot as there are shiny areas on the sides where friction has occurred. I set them up in the lathe and machined off a minimum amount, just enough to clean the sides. The rear bearing had just started to break up, this is a very small bearing at 3mm id x 6mm od x 2.5mm tk. Part of the metal dust cage had come out and some balls were missing, so I removed the what was left and replaced it with a spare. Now in the middle of reassembly. Should have it running again soon.
Off to Cornwall this coming weekend, but I don't hold out much hope of having it ready in time. There's too much work to do on the aircraft (Ultimate Biplane).

Not much left to do

2010-07-26T07:31:00.003+01:00

Two holes to be drilled and tapped M1.6 in the bottom of each conrod and then the shells have to be made. Like the small ends, the big end shells are made from Phosphor Bronze. Two flat pieces are soft soldered together, held in a four jaw chuck and drilled (under size at this stage) on the joint. Then the outside diameter is turned to size and parted off. Warm gently to melt the solder and split the shells. Fit them in the big ends and tighten with the M1.6 screws, then set up on the mill and bore the big ends to size. Job done. Then its a matter of fitting it all together and seeing if the engine runs.

To give you an idea of the size, the distance between centres is 29.0mm.

Conrods with small end bearings fitted

Nearing completion, but its a lot of tedius work

2010-07-18T05:42:00.005+01:00

The crank shaft is almost finished, its been hard work as only small cuts at a time can be taken so as not to strain the setting. Its only held between centres in the lathe and if a tool were to pick up it would be disaster. As it is I'm very pleased with it. I need to reduce the weight a little and I've been studying some pictures of the Saito twin cylinder crank shafts and the balance weights have been shaped as a semi diamond on both sides ie where the counter balance weight would be. So I'm going to do the same.

You can see what I mean by the diamond shape...

I need to cut the same on the other side.

A Jet event at Westonzoyland

2010-07-12T06:59:00.004+01:00

This was by invitation only and some pilots from the South East area Arrived on site for the weekend to "have a go" at flying from tarmac for a change. Everyone enjoyed themselves and there were no accidents or incidents. Normal Club flying activities continued as usual and the whole event went very well.

Some engineering at last

2010-07-09T05:51:00.003+01:00

I've shelved the earlier crank shaft and decided to manufacture it a different way. This is how its done... a picture paints a thousand words, so here's a video.

Spent the day flying

2010-06-20T22:56:00.002+01:00

A cold wind from the North but it slowly warmed up as the day went on. The wind increased in strength and became gusty making flying conditions difficult as landings had to be cross wind. Just after 13:30hrs and I was the only one there after a good crowd earlier. Jim and Ian turned up with their jets later and the wind calmed a little and direction changed to the North West.

I really must get on and do some engineering...

Thats it for a while!

2010-05-13T07:18:00.002+01:00

I case you're wondering what been happening, I've been doing this!

Another Crankshaft Failure

2010-04-24T20:12:00.005+01:00

Yes, it failed again. This time it twisted slightly which meant the pistons didn't reach top dead centre at the same time, and the central crank web was rotating eccentrically in the crank case. This also meant the valve timing had slipped and the pistons were just hitting the valves of one cylinder. Luckily no damage was done, and now I've decided to manufacture a one piece crankshaft and the material arrived this week. Its a good job I made the crank case with a bulge in both sides as I'm going to need that internal volume for the much larger two-part big ends of the conrods. The material is an alloy steel, EN16T which is a tough steel, good with torsional strength. The down side of all this is that (as I mentioned earlier) I have to make two new conrods with a split big end and a split bearing. This bearing is made by soft soldering two pieces of phosphor bronze together and turning the bearing as one piece, then heating it up to melt the solder to form the two big end shells.

To give you an idea of the size, the cutter in the photo is 6.0mm diameter.

Crankshaft during remanufacture

Best day for flying so far this year

2010-04-10T22:16:00.005+01:00

Wall to wall hazy sunshine and light winds from the East. I thought it best to go today as the weather for tomorrow (Sunday) is breezy. Took the Pico-Jet, Sunbeam and the Yak and actually plucked up the courage to fly it. Had an engine cut shortly after take off, despite extensive pre-flight testing. The next flight was OK, but I had to stop to video this:-

Ians F16 is always an impressive display.

Two flights with each aircraft today, and I brought them all home in one piece - a very satisfying day.

No April Fool

2010-04-01T07:10:00.010+01:00

So this blog is about yesterday. (Wednesday 31st March 2010).

I've managed to re-assemble the KT120fsT and fit it to the fuselage of the Ultimate. I packed it all into the car and took it to work because at 19:00hrs the factory hooter goes off and I shout "Yaba Daba Doo"! (Flintstones connection) and then its time for a quick sprint over to the George Inn at Middlezoy to enter the Sedgemoor Clubs' Craftmans Cup. This is a chance to see what club members get up to in the cold dark Winter months.

A fine array of models had been built among them an Augusta helicopter, a Hawker Typhoon, a Corsair, and a Kyten. All very nicely finished, and of course its good to get together and have a natter.

2010 to be engraved

The Craftmans Cup 2007

Ketro KT54fs

The Craftmans Cup 2010
Ketro KT120fsT

Right! Whats next? How about a KTxxxfs7R? Hmmm, maybe??? What do you think?

A new Central Crank Web and Big End Journals

2010-03-28T21:36:00.010+01:00

On examination of the old assembly it appears the screw pin location hole was drilled and reamered on the p***. I don't know how I managed that, hence the resulting stress fracture. So, back to the drawing board to make a new one.

Jig set up for silver soldering the big end journals into place.

The new Central Web complete with Big End Journals

The journals are too long at the moment and will have to be cut to length to enable fitting between the front and rear crank webs.

I removed the shaft from the gear box because the bearing was lumpy, but it worked fine after I'd taken it out, so I cleaned it all up and noticed the shaft was bent. This could be the cause of the lumpyness, so shaft straightened and re-assembled into housing, it now works fine again.

Disaster!

2010-03-22T20:14:00.005Z

I tried to fire up the KT120fsT today, and with very poor results. I managed to get it firing on one cylinder and occasionally it attempted two, but that is as far as things went. It all ended in tears when suddenly things came to an abrupt halt. I couldn't turn the crankshaft through a full 360, there was a stop preventing it going any further. Time to pack it all in and have some tea.

Broken crank pin

After tea I began dismantling the engine and it wasn't long before I discovered the crank pin on the central web had severed. I've also noticed the other pin in the web is loose. I must have done a poor soldering job there. Nothing else in the engine is damaged although the bearing in the gear box housing is a bit lumpy. I think I will change it.

A sorry sight

Nearly finished

2010-03-21T19:17:00.008Z

Yes, its almost ready to be fired up. Just a few odds and ends to finish off. Loads done today, I was hoping to position the carburettor on top of the engine, but there isn't quite enough space inside the cowling so plan "B" takes effect and the carb is mounted under the engine mount, between the exhausts.

View of the front underside

The carb is mounted with a 4.5mm offset. This is to compensate for the differing lengths of delivery tube. (They are different due to the 9.0mm cylinder offset.) The 4.5mm offset makes the mixture transit distance equal to both port and starboard cylinders.

Temporary fitting to the firewall

View of the rear with mount removed to show delivery tubes

The delivery tube system is made from 10mm micro bore tube and two standard elbow fittings. These fittings were modified to remove the solder ring and to add lightness. The two joints either side of the carb are butt joints. All the joints on the delivery tubes are silver soldered and there is a spigot silver soldered to the main part which extends into the carburettor manifold and the aluminium adaptor is glued to the spigot using Loctite 603 oil tolerant retainer. The carburettor is held in place using two M3 grub screws.

I can hear it running already!

Made light work of more progress

2010-03-13T14:26:00.012Z

Placed some strategic holes in the base plate to add lightening. They were designed for position and size, in other words not randomly placed.

Lightening holes (Not lightning holes)

I also made the exhaust pipes, large in diameter to muffle the bark. Aluminium inserts are pressed into each end of a stainless steel tube and the assembly is screwed to the cylinder head using an M3 socket cap head screw.

Exhaust stacks fitted

I've just looked back through my blogs and discovered that I started building this engine late in 2008

I went flying today as the forecast was good and with light winds. 'Tiz different when you get there, it was good earlier but the wind got stronger for the North West and by lunch time it was really cutting and Ipacked up and went home. Not before flying the Sunbeam and the Pico-Jet, and on the second flight with the Pico-Jet the prop parted company with the motor. All the bits flew off and scattered on the runway - time to land.

Phil was there with his Funtana. Look at the kit he's got to charge the batteries. That's not all, there's also a generator to power it all up.

No less than FOUR chargers

Phils Funtana

Exit left

Engine Mount and First Trial Fitting

2010-03-07T21:10:00.008Z

Started and finished the engine mount, and fitted it to the Ultimate to see how well it fits. The pictures tell more:-

Bags of room inside - Could've built a bigger engine

Exposed, showing the mount.

6mm dia. base, 8mm dia. spacers tapped M4 both ends

4 Degree angle

The original holes in the firewall are drilled at a 4 degree angle. This is to accommodate a large two stroke engine with a larger diameter cylinder and designed to fully enclose it so that unsightly holes don't need to be cut in the cowling. The KT120fsT needs to be horizontally mounted so the plate needed to be adapted.

Base is made from cast plate for lightness

So far it weighs 670 grammes including the mount, thats 1lb 7.5oz in old money. Not bad for a home build 24cc twin. There's a bit more to add, carburettor, manifold and delivery tubes, and exhaust pipes.

Things are beginning to get exciting...

2010-03-01T20:17:00.004Z

Getting very close to the day when I can put some fire in its belly. I have to say, I'm very pleased with the way its turned out so far, there's been some difficulties, but I've designed my way out of them. All that's left to do now is make a pair of exhausts, the inlet manifold, mount the carburettor and make an engine mount suitable for the Ultimate Bi-plane.

Here's some pix:-

Gearbox cover detail

Starboard cylinder head close-up

Prop driver assembly fitted

Full view of the rear (top)

Underside

Indoor flying

2010-02-25T05:48:00.009Z

Went to the local market venue Junction 24 last night and met about fifteen other pilots having a go in what was a very enjoyable evening. There were loads of mid air collisions (I had two, one with a helicopter) and no-one suffered any damage. I've heard people talk about the Vapour but I've never seen one untill last night. Even more lightweight than the Ember, and it can fly a lot slower.

Phil shows how its done.

One thing that surprised me was the noise, it got very loud at times and the high pitch really gets on your top note. Its not the propeller or the motor, but the speed controller that makes the noise. Next time I'll wear ear muffs and maybe, if I remember, I'll take along a decibel meter. We might have to fit silencers for indoor work.

The Vapours

Progress, but with Major Modifications

2010-02-20T22:06:00.004Z

Today I discovered that the valve and rocker assemblies were not going to fit together with the correct geometry. I had to remove 5.5mm from the length of the valve guide as I'd designed the posts on the cylinder heads for the rocker shafts too short. This also means the valves need to be shortened to 22mm from 25mm leaving just enough room for the spring to almost fully compress. Bottom line is, it looks like I've recovered from the disaster I thought it was and saved some weight in the bargain. Phew!

Exhaust Valve, Retaining Seat and Collet Set

Click on the picture to enlarge the image

To give you an idea of the size, the valve stem is 2.5mm diameter and the overall length is 22mm.

New parts made today include four valve spring retaining seats and two pairs of collets, two more to make.

Even more on Rockers

2010-02-19T23:05:00.009Z

This engine is all about design and development. Having learned a lot during the making of the KT54fs more thought has gone into the KT120fsT. I've decided to scrap the steel rockers and go for aluminium to reduce the mass/inertia problems that may occur at high speeds. Not that I'm expecting massive RPM figures, but every little helps, and it reduces the overall weight. The tips at the valve end are, of course hardened and tempered Silver Steel, and I've fitted Phosphor Bronze bushes at the fulcrum.

New design Rockers

I've also redesigned the cams, based on my original design but larger to prevent stress and wear to the gearbox housing. The radial holes are strategically placed for timing purposes when setting up the lobe separation angle. Here I have a choice, two of the holes in alignment will produce 106 degrees and the other two 110 degrees. The profiles were generated using a zig-zag of co-ordinates worked out on AutoCad and the resulting ridges dressed out with a file. The inlet cam is designed to open comparatively sooner and quicker than the exhaust, stay open longer and close later, thus allowing more mixture into the cylinder for combustion. Both cams have a 2mm lift.

New design cams, exhaust on the left

You should be able to take a closer look at the pictures by clicking on them. In the Rockers picture the cap head screws at the tappet end are M2.5 and the hardened steel tips are held on with M2.0 cap heads.

First flights of 2010

2010-01-18T20:15:00.014Z

Westonzoyland airfield was deserted today, so I had the whole runway to myself. I've not been flying since November 15th last year and I see some work has been done to improve the pits area by scalping back the over growth. It looks much better and well done to all those who did it.

I brought the Sunbeam today, but I wish I'd brought the Yak and the Pico-Jet as the weather was perfect. Lightly broken cloud and a light air moving from the South West. Taking off and landing in any direction would not be a problem in these conditions and due to the conditions I had some perfect landings. There's something very satisfying about a perfect touch down.

= new parts

On the engineering front I've sucessfully case hardened the gears, hardened the rockers, manufactured the cams and hardened them and the cam followers are manufactured and ready for hardening.

More on Rockers

2010-01-09T19:45:00.002Z

Finished them today...

Rockers

2010-01-03T20:00:00.009Z

Two different sizes for Port and Starboard, this is to compensate for the 9mm stagger on the cylinder alignment and to ensure that the Port and Starboard valves operate with equal geometry. Two 3mm dia. holes have been drilled in each Rocker, the centre is for the fulcrum and the other is for lightening. To manufacture the Rockers, I've made a fixture to machine the lightening necking and to drill and tap the M2.0 threaded hole for the Tappet adjustment screw. All this will become apparent when you see the finished items in a future blog. In the mean time, here's some pix of what I've done today:-

Blanks cut from the material they're sat on. (5mm Gauge plate)

The fixture for cutting the necking.

Ready to start machining...

I learned today the results of my AGM proposal to pit on the North side of the runway when the wind is from the South. A resounding failure in the voting, 5 for, 19 against. The reasons given were due to a motor cycle training school setting up on the Southern perimeter and the main road being nearby. In fact, setting up on the South side means you are a runways' width closer to both. Oh! well, I guess I'll not be going flying when the wind is from the South in future as I don't feel safe in the pits when others are taking off towards the South side. I wonder if someone decides to set up a business near the North side of the runway or on the Hammer head, if we'll get kicked off the site due to health and safety reasons. It could so easily happen.

Happy First Day of the Year

2010-01-01T18:46:00.005Z

I thought about going flying today and I even put my gear on charge, but it was quite windy here at home so it would be twice as windy at Westonzoyland. Second thoughts, I'll do some engineering. Finished the gear box today.

On the Rotary Table having the radii machined

Upper side showing assembly detail. See also last Photo

Underside, showing cam shaft housing

Its all in the detail

More engineering - started a new part.

2009-11-28T22:21:00.016Z

I did some work on the cylinder heads today, and drilled and counter bored the ports for the inlet and exhaust. They're finished now, apart from the holes for the rocker shaft. Check out the pictures:-

Cylinder heads very nearly finished

I started the gearbox, not much done yet, just the flange face, location diameter, bore for the bearing, and clearance drilling for the primary gear.

Gearbox started

Weather stopped flying (yesterday)...

2009-11-23T06:31:00.004Z

...But it didn't stop me doing some work on the Ketro KT120fst engine. I've not been satisfied with the design of the crankshaft where two M3 grub screws hold it all together. So I've come up with a design modification that will beef up the strength and rigidity. I made two special screws from M4 cap head socket screws and I turned off a section of thread to form a 3.0mm dia. pin whilst leaving a threaded section intact. Then I drilled and reamered a 3.0mm hole through where the original M3 thread was in the crankshaft parts, followed by an M4 thread down to the center, and counter bored 6.0mm dia. to contain the screw head, which incidentally, I turned down to size. Now I have far more confidence in its integrity.

More integrity

You can see the screw head in one crank and the pin in the other. Unfortunately there is a little bit of run out along the length of the shaft, but I'm hoping the rear bearing set will contain it.

I went flying today.

2009-11-15T20:38:00.007Z

The weather this week has been appalling with heavy rain and gale force winds at times. Today, it was superbe with sunshine and light cloud and light winds. A day not to be missed. Tomorrow is forecast to be back to heavy rain and gale force winds.

Jamies Bobcat now fitted with larger Jetcat P80se

The Front Housing and some assembly

2009-11-14T21:36:00.010Z

Well, just enough to see if it fits. I made the Front Housing and fitted the crankshaft and conrods together in the crank case. 'Tis at this point I've discovered I need to remove a very small amount of material from the bottom of the sleeves because they foul on the crankshaft. Oh! well I can't see it making any difference to performance other than it just makes the engine that little bit lighter. Every little helps.

Here's some pix:-

Front Housing in the lathe for final machining

Note how its bolted to the mandrell

The rear end view

Assembled (temporarily)

Next will be the gudgeon pins and the PTFE end pads to prevent the gudgeon pins from scoring the bores. Then I can get the pistons moving.

Some engineering works

2009-10-25T17:06:00.010Z

As I haven't blogged for a while, especially on engineering, I thought (careful) that I'd make an update. I've finished the inside of both cylinder heads today leaving just the ports to do, and to give an idea of how far I'm ahead (or behind), I've taken some pix of everything.

Using a boring bar to form the valve seats

Crank case, cylinders and liners

Pistons and valves

Cylinder heads, port and starboard

Crank shaft complete with conrods and bushes

Preparing for finish machining

The best conditions...

2009-09-26T20:13:00.006+01:00

...for flying today. Jim flew his Mig, Ian flew his F16, I flew the Yak, and Brian flew his Piper Pawnee. The weather was so good, I managed a couple of flights with the Ember.

Brians Piper Pawnee

Brians Piper is a nice model, built from a Hangar 9 kit, its an ARTF powered by an OS 52 fs four stroke engine and guided by Spektrum 2.4 Ghz radio.

Ians F16 was impressive, together with smoke system, he has afterburners in the tail pipe. Actually, its an array of ultra bright LEDs switched on by a micro switch at 3/4 throttle and above. Had me and Jim fooled as there was some flames exiting the tail pipe on start-up, so we thought it was alight while it was flying.

There was a lot of microlight activity today, this is a particular menace to the jet pilots as jet aircraft use up so much airspace. Microlight pilots don't seem to be aware of the dangers of flying through our airspace. A record of the number of movements was taken today.

A drawing error - oops! conrods

2009-08-22T08:08:00.009+01:00

Its about time I blogged some engineering, so I've done the following:-
Some how I cocked up. Its not the first time, nor will it be the last. Getting down to it, I designed, drew and made the conrods too short. The piston was unable to pass bottom dead centre. Oh! dear, how sad, never mind. But now I have two new conrods of the correct (longer) length. This also means I'll have to remove some more metal from inside the cylinder heads to maintain the correct compression ratio.

Ahh! Bottom dead centre

Conrods increased in length by 0.5mm

I went flying today, and it was a sad day. I lost an old friend. Yes the red Sunbeam met its match or rather terra firma. It was pilot error, I heaved in too much elevator and the wings folded and it went down into the bean field. Engine and radio are OK but the airframe has had it. At least I know it was my own fault.

Cornwall - The Show

2009-08-10T20:11:00.006+01:00

The two day event at North Cliffs near Camborne was a total success all round. We ('erin doors and I) trundled our way down the A30 to Camborne and arrived on site at around 09:00hrs on the Friday. First things first, set up the caravan and put up the awning. Geoff and Mary arrived shortly afterwards and did likewise, only theirs is a motor home, and then Terry arrived and erected his tents. Yes plural, the other one is his dunny. I won't go into details. After a spot of lunch we chilled in the afternoon and enjoyed a couple of flights with the Pico-Jet and Geoff flew his very pretty looking Bae Hawk. Evening, and we went into Portreath and paid a visit to the Bassett Arms for a jar of Cornish Knocker and a bite to eat. After a stroll down to the sea front to watch the Sun set we made our way back to the site and crashed 'till morning.

Saturday, and up with the (bleary eyed) lark, took all the models and equipment down to the flight line and made ready for the days' flying.

Early Saturday Morning

Terry watches Geoff contemplating his "Ork"

Getting to grips with the Laser 200

Spotted at the show. I just had to take this photo.

Apparently they're called Truck Nuts

Sunday wasn't quite as good as Saturday weatherwise, although it didn't rain it was cloudy all day. In fact it rained most of the day on the South Coast, so prospective spectators were probably put off attending and as a result there were fewer spectators on Sunday. But it was still a great day.

In preparation for Cornwall

2009-08-02T19:09:00.007+01:00

Flew all the usual suspects today and gave the Pico-Jet a particular airing to test all four li-po batteries. Everything performed well.

Ian flew his F16 Fighting Falcon Fitted with a smoke system. Boy did we have some fun with that. After landing Ian taxied back to the pits, and as he got close to Geoff, who was working on his plane, switched on the smoke and Geoff completely disappeared in a huge cloud of white vaporised diesel.

Pete brought along this nice example of a Comet. It crashed on its first take-off but there was little to no damage, just a few scratches, and the second attempt was a success. Sounded nice in flight for an electric job.

deHavilland Comet "Grosvenor House"

Next weekend, its a trip to Cornwall to fly in the Annual Two Day Model Airshow hosted by Redruth and District MFG at their site on North Cliffs West of Portreath. This has coincided nicely with the NSA who are having Westonzoyland Airfield for the weekend for their "flying" event. (NSA is the National Sprint Association. They ride motorcycles).

Yeovilton - a big disappointment...

2009-07-11T20:08:00.011+01:00

...and it was mostly down to the weather. A few aircraft flew in the morning, but the show consisted mainly of helicopters. Lynx Mk blah de blah, Sea King Mk whatever and Merlin ad nausium, sorry, helicopters just don't do it for me. However there were some exciting bits, a Sea Vixen (remember those?) put on a sedate display, the Red Arrows flew in and did a couple of flypasts and buggered off to somewhere, a Rafale did some impressive manoeuvres and an F16 Fighting Falcon showed off its afterburner. With the cloud base at only 300ft anything fixed wing was very limited and much was cancelled, which included the Avro Vulcan, not just because of the weather, but because it had suffered a hydraulic oil leak in its braking system. Ah well, such is life.

It started to rain at around 16:00hrs just after the Commando assault got under way. We watched it for a while but the start was so slow and we got bored and walked back to the coach. Then it all started, very large bangs with huge plumes of flame and thick black smoke, and the dreaded helicopters buzzing around like demented buzzing around things. While we sat on the coach we could see bit of it going on in the distance and when a plume of fire and smoke went up it was some time before the boom reached us and when it did it shook the coach.

I have to say that despite all I had a good day.

Here's some short video clips:-

de Havilland Sea Vixen

Visitors from Belgium and a real flyer

2009-07-05T05:59:00.013+01:00

The cross wind from the South made flying a little difficult and with the speed at around 12mph it was really beyond the limit for me, but I did manage to fly the Pico-Jet and both trainers, but I left the Yak on the ground.

Jack and Josie B from Gent in Belgium were here this weekend on a visit. They used to come to the Top Gun events which the Sedgemoor Club hosted many years ago. Its great to see them again. Jack flew a large scale Extra 300 with a 3W engine running on Avgas (used in full size aircraft) which gave a remarkably slow and smooth tick-over and good top end power. Its also equiped with a smoke system using lamp oil (not much smell). It produces an excellent smoke trail even in todays windy conditions.

Jackies Extra

Another unexpected visitor to the airfield was this beautiful owl brought here today by Paul and his wife.

The eyes are amazingly clear as crystal

And of course there's always a poser

Dull day and a new jet

2009-06-28T21:06:00.007+01:00

Strange weather today, 90% cloud and very warm and humid, winds light and from the South East. Positively tropical. The pits were full and crews were overspilling the pits area at both ends, and despite the wind direction we were deployed on the South side pits.

I arrived shortly after 09:00hrs and started the days flying with the Ember as there was no wind. Whilst in electric mode the Picojet was next. Two new digital, metal gear servos were fitted this week and their reaction to stick movement is very fast. I still need to add lead to the nose as its very twitchy on the elevator. I hate doing this but I can't lighten the tail any more. I'm also a bit worried about over heating the lipo battery so I use full power frugally. The heat in the air was creating thermals and a short five second burst of power would take the Picojet vertically to near out of sight. Stopping the motor and gliding seemed to last for ages before much height was lost.

Late in the afternoon I decided to give the Yak an airing, but as I prepared to fuel it up it started to rain; just a few big spots, so I took that as a warning and packed up all my gear. Turned out it wasn't enough to damp the dust - typical.

The Bobcat

A New Jet on the Blog

Jetcat P60

The connection at the top of the engine is a PTC heater where fuel is ignited as it enters the combustion chamber on start up. This eliminates the need for gas and the associated equipment.

Ballistic

2009-06-13T21:10:00.007+01:00

First flight today was with the Picojet, and its fast, really fast at 22,000 RPM it positively honks along. From gliding into wind I can point the nose upwards, open the throttle, and it accelerates vertically and within seconds its almost out of sight. I had a serious problem on a later flight, the elevator was responding abnormally. Up elevator would force a left turn, so would left aileron. Right aileron would force a right turn but it would also lose height rapidly. Eventually it crash landed in the grass and without damage, luckily. The cause? Starboard servo failed in the centered position. Reason undetermined.

Quite a good turnout for a Saturday:-

I was last to leave!

Also flew both Sunbeams, I took the Yak54 but I didn't fly it because the wind was directly across the runway from the South and it was up to maximum strength where flying is concerned.

Its been a funny old day

2009-06-07T20:40:00.009+01:00

Arrived at the airfield at around 08:40hrs. and set up on the South side of the runway. The weather was cloudy, but brightening up, and a light air moving from the North East. Time to fly the Ember but not long after it got airborne the wind became a bit stronger, so it was time to land and put it away. The direction settled South Easterly which meant changing the pits to the North side of the runway. That done, Picojet next, and I had a new motor arrive for it yesterday, an in runner this time, and its a bit longer and heavier than the out runner fitted previously, so I thought there may be an issue with the centre of gravity. A balance test showed it should be OK but only a flight test would prove it. I tested the speed of the out runner motor before I removed it and the result was 18,000 RPM on a 5.25" x 4.75" APC propeller. This new motor tested out at 22,000 RPM on the same prop. Imagine what it does when it "unwinds" in the air. Right, lets get it airborne, and what a difference. Its now positively ballistic, but tail heavy making it twitchy on the elevator. I glued some lead into the nose (something I hate doing) to improve centre of gravity position, and a flight test proved it was better, but more weight was required in the nose. But what I'm going to do is move the motor forward as far as it will go so hopefully, no more lead needed. Will keep you posted.

Later a Club Committee member arrived (who shall remain anonymous) and insisted, despite the wind direction, that I change to the South side as it is the Club rules (its not, I double checked),and he refused to fly from the North side. So this means taking off and landing down/cross wind. Anything for a quiet life, so I moved all my gear back to the South side. Paul M and Jim E arrived later and they both asked "Shouldn't we be over the other side?". I had one flight from this side but landing was a bit awkward as the pits were in danger of being in the way, so I didn't fly again until he'd gone and then we all moved to the North side. One for the AGM in December me thinks.

Jims OS Gemini 240 powered Firecracker

I haven't seen this aircraft fly for years, in fact I can't remember the last time I saw it fly, and I still haven't seen it fly. Jim put it together, fuelled it up pumped up the retracts, and prepared to fly and it started to rain. We had enough to seriously wet the aircraft, but barely enough to dampen the dust on the runway. So Jim defuelled and dismantled and packed it up into his car. then the Sun came out and it turned out nice again. Sh!t happens.

Also in the picture is Pauls Ducted Fan F15 Eagle and Fournier powered glider.

31st May 2009

2009-06-01T05:36:00.017+01:00

I should have done this on the day, that's why I've dated the heading.

A really superb day weather wise although the wind was a bit strong at 8 - 10mph. I took the Yak 54, Sunbeam 1, and the Ember (tempting fate) and flew them all, but the Ember was a very short flight, just up and down again during a quiet spell. That was enough, it was still too windy. I wanted to take the Picojet, unfortunately one of the magnets had displaced itself and It was difficult to get it back in place. Also the bearing had come out of the rear cover so I had to glue it back in again. I think that's poor design. I don't think I'll buy another out runner motor.

A minor accident occurred today, a Club member had landed an electric biplane safely and parked it in the pits. No problem so far, and then picked up his electric glider, and after changing models on the transmitter proceeded to launch the glider having not done the full pre-flight checks. Once the glider was launched, he then switched on the motor, which also switched on the motor on the biplane he'd been flying earlier! It moved forward and hit him in the legs, and whilst looking down to see what had happened, the glider nosedived onto the tarmac. Fortunately there was no injury caused but the glider didn't get away with it so lightly. What he didn't do was disconnect the battery in the biplane before launching the glider, both aircraft being on the same frequency. We live and learn... or do we?

I took some photos of Malcolms Magnatilla to record the how he fitted his four stroke engine. This will be useful information for when I build my Legionaire. The aircraft has a very short nose and its a bit of a tight squeeze getting it in there.

Malcolm says the OS 70fs is way overpowered

Firewall cut away to accommodate carburettor

All pictures shown with rather nice aluminium cowl removed.

That's all for now folks.

Its all about change

2009-05-23T21:00:00.017+01:00

Well, in case you were wondering, I didn't get to fly the Ember when I was on holiday, the wind was far too strong even early morning and late evening every day. The strongest wind for flying it in is a light air movement, and we had more than that. (understatement).

Today...

A 180 degree turnaround in the wind direction today meant changing to the other side of the runway - twice. When I arrived we were on the South side. The wind soon increased in speed and the direction settled in the South East. All change, pick it all up and move to the North side. By the afternoon the wind changed and steadily moved to a Westerly direction. At around 15:30hrs the wind dropped to zero mph for about 10 minutes and I managed to get a flight in with the Ember. (Designed for indoor flying). Then it quickly built up speed from the North West to about 15 mph. Then it was time to go home. But I did fly all the aircraft I took up there today, and brought them home safely. Others weren't so lucky. Clive brought along his Harmony,a nice twin engined job which had an engine synchronising unit on board which used sensors one on each engine to monitor rpm.

Clive Halls twin engined aircraft met its demise on the tarmac - what a shame, nice plane.

Ian arrived later in the afternoon and flew this beautiful example of an F15 Eagle. Powered by a single Jetcat gas turbine it has bifurcated jet tubes to simulate twin engines. Also there is retractable under carriage with synchronused doors, wheel brakes, air brakes, flaps, and a canopy that opens using compressed air.

A fine example. This photo shows the wash-out on the wing tips.

A side view

I nearly forgot, I flew the Pico Jet today as well. First time since...must be last year.

I'll post more later...

Home again

2009-05-17T13:14:00.003+01:00

Been away for a break on TQ, thoroughly enjoyable but the weather has been awful so I've not been able to do any flying at all. We were on the River Severn last Sunday and ahead of us at Upton-on-Severn was a glider, two, in fact, so there must be a club site nearby. That Sunday was the best day of our holiday weather wise, but I was unable to find the time or place to do any flying. The weather today is still pretty appauling so lets hope next weekend is better. No pics today, however I've got a new camera so I'm dying to try it out at the airfield.

Another great flying day

2009-05-02T17:54:00.007+01:00

The fly for fun went really well. No-one knows where they came in the competition, but everyone enjoyed themselves. All I can say is I think I came second in the climb and glide event with 4 minutes and 52 seconds of glide from a 30 second climb. Not bad in my book! The events were Pylon Racing, Climb and Glide, Touch and Go in a minute, Spot Landing, and Loops in 30 seconds. Thanks go to Mike Clark and Niel Hincks for organising and running the event.

Another highlight of the day was this Piper Cub built by John Wright and flown by Paul Mancini. The pictures say it all...

Well thats it from me for the next three weeks as I'm doing this instead. However I may just slip in a post or two as much to Lins disgust I'm taking the Ember. Cheers for now!

Fly for fun today...

2009-05-02T07:19:00.004+01:00

...and the weather forecast is good. This is a club day where we fly as individuals in competition events such as Spot Landing, Climb and Glide and Pylon Racing etc. I'll be flying my Sunbeam trainer with the Super Tigre 40, and the other Sunbeam (Irvine 25 powered) will stand by in reserve. The Yak would be useless for this as its a bit of an animal.

I'll blog again later today if I can find the time as we're doing this for the next fortnight. If not then I'll write it up when I'm doing this.

Fantastic day

2009-04-20T19:17:00.012+01:00

Definitely the best day so far this year. Wall to wall sunshine and WARM! The pits were nearly full all day, that's amazing for a Monday. Jim who was there yesterday said there wasn't as many people.

Good for a Monday

I've been flying the Yak 54 today and doing some engine tuning. The engine runs fine on the ground but when it gets airborne it misfires even at full throttle. I've changed the plug for a cooler type and it has improved a little but the biggest improvement came from a change of propeller. A 15" x 8" Master Airscrew for a 15" x 8" APC. It hasn't cured it but it has improved.

One other little thing, I've acquired an indoor R/C aircraft. It comes complete with everything you need to fly now - even the batteries. On the aircraft there is a very small circuit board with two servos, a receiver and a speed controller mounted on it. The transmitter has trims on all four channels, is switchable mode one or mode two (throttle right or throttle left) and is on the new 2.4Ghz frequency. As there was no wind first thing this morning, and I gave it its first outdoor flights. Its not easy to fly as its a bit twitchy and needs some expertise.

The 16.5" wingspan Ember

I'll finish todays blog now, I'm going to try the Ember in the garden before it gets dark. Until next time...

To the South West Model Engineering Show

2009-04-19T21:13:00.005+01:00

Went to the Shepton Mallet Showground to see the SWME Show. A little disapointing really, not much flying going on and then only one aircraft airborne at once with long silent breaks in between. In the halls were a lot of working tanks and militaria complete with owners in camoflague, war gaming enthusiasts and a few interesting Stirling Engine projects, even a radial version. Another interesting project was a nine cylinder rotary, yes rotary engine, an amazing scale working model of a Rolls Royce original. Puts my attempt to shame.

A snapshot of the local Pitney Club stand

I must say I did enjoy the day, but would I go next year?...

Todays forecast is good

2009-04-11T07:19:00.010+01:00

I've charged up all three aircraft overnight and I'm getting ready to go flying. I have to go today as I have to work Easter Sunday and Monday. But the forecast is good, so I'm happy. And this means when I get home I'll need to cut the grass for the first time this year. I don't like to cut it too early because it makes it grow much faster and another cut is soon required, but now I have to bite the bullet and get it done.

I tied up the tail feathers on the Ultimate this week so thats a bit further ahead. Theres a lot of work still to be done on the engine, its nowhere near finished.

Ultimate tail feathers

It was a bit breezy up to around 8 mph from the North West and very chilly but the sun shone all day.

I'm so pleased I went today as Gwyn from Cornwall arrived. Last saw him in early August last year. He's here with his caravan 'till Tuesday when he travels to Spain. Its great to see him again.

Gwyn in happy chappie mode

What a day!

2009-04-05T17:50:00.006+01:00

Sunny at home, but as I got closer to the Somerset levels the fog was getting thicker, and at WZ it was too thick to fly in. I unloaded the car and parked up and as I was assembling the aircraft the fog was burnt off leaving bright sunshine which lasted all day. Winds were very light and variable to start with but increased later with a Southerly direction.
I'm beginning to enjoy flying the Yak as my confidence in the radio is being restored. I tried some knife edge flying today and discovered the aircraft does it very well, unlike me, and the new canopy stayed intact too, another bonus.
Flew both the trainers, and a former club member visited, haven't seen Martyn for 10 years and he hasn't flown for that time either, so he had to have a go, and he did very well. I didn't have to prise the transmitter from him once. Mind you, when it ran out of fuel he couldn't thrust it back to me fast enough.
Jim flew his Hotspot jet, always impressive, see the video, and he'd been flying an electric "jet" with a rear mounted motor which propels this thing along really fast. the motor turns at 45,000rpm and sounds like a Formula One style V10 engine. Unfortunately something went "pop" and all power was lost. Turns out the motor shaft snapped clean off, losing the prop.

Its early morning...

2009-04-05T05:42:00.004+01:00

...and the birds have just started to sing. Earls up and off to a car boot sale (best of luck) and I'm left to feed the cat. Then I'm off flying all day. After all its my only day off this week. The new canopy for the Yak arrived this week and I fitted it last night. Its a better fit than the original and I glued it down with Pinflair silicone glue (from Lins paper crafting) as well as the screws provided. The glue will give it some stability and resistance to vibration. Also I fitted a volt watch monitor in the cockpit.

New canopy and Voltwatch

I've had my fix for the week.

2009-03-21T17:25:00.008Z

For a Saturday there was a whole load of pilots here today. The weather certainly brought everyone out. There was a chilly wind from the North West at around 1 mph in the early morning, but it gradually increased in speed toward the late afternoon to around 10 mph.

Geoff enjoying a flight with his Mustang

I've made a temporary modification to cover the holes in the wing of the Sunbeam. It flies a lot better now, but I'll have to make a more permanant effort and use Solarfilm instead of Sellotape.

Wing slots temporarily covered.

Ron brought along this nice little delta. All balsa construction with tissue and dope finish - no paint!

Nice delta.

Now I can go to work tomorrow refreshed as having been flying today. Trouble is, two hours and its as if I've not had a week end at all.

Flying today...

2009-03-15T20:33:00.015Z

...Just for a change. I say that as I've been a bit busy with other things lately. Nothing connected with flying or engineering, but a holiday aboard TQ, and since then, I've been decorating. Finished that for now and I'm moving my modeling workshop into that room. Its a bit smaller but I think less junk will be dumped in there as there's no room for it.

In the process of moving in.

The weather brought out a few more pilots than usual today. Wall to wall sunshine and a (cold) light breeze 6 - 8 mph from the North-West. Flew the Yak and the Sunbeam, and Malcolm asked me to fly his Flair Magnatilla, a maiden flight. Powered by an OS52fs four stroke engine it had plenty of oomph! Required some trim adjustments, and an increase in aileron and elevator movement, and some more down thrust on the engine to stop the "ballooning". All this knowledge is good information for me when I start building my Flair Legionaire for my Ketro KT54fs.

Sorry there's no pictures of todays flying, I forgot the camera.

Flying today after...

2009-02-16T20:16:00.012Z

...a weekend decorating our bedroom. Eventually it's going to be my modeling workshop and the current workshop is going to be the bedroom. It'll be nice to have a clean start, but at the moment our house is a tip. So I painted the final under coat this morning, and while I was waiting for it to dry properly, I went flying. Took both trainers and the Yak, and actually flew the Yak - twice. It was quite a good day, although cold and windy, around 8 - 10 miles an hour from the North-West, almost on the comfort limit.

I did a proper radio range check on the Yak today and found it had a range in excess of 70 metres. Far more than twice that recommended.
Powered by Super Custom SC108

Guided by Spektrum DX7

Conrods and a spinner nut.

2009-02-01T20:30:00.004Z

Far too cold and windy to go flying today, so more on the KT120fst.

Getting there with the conrods, just the small end bushes to make and fit. After press fitting they'll need to be faced to length and reamered to size.

Another little project I made for my mate Geoff - a spinner nut tapped 1/4" UNF.

Conrods

2009-01-26T19:08:00.010Z

The fixture I made earlier for machining the conrods is very successful.

Just the thickness and central section left to machine. To give you an idea of the actual size, the bores are 28.5mm between centres. Next is to turn up the phosphor bronze bearings and press fit them into the bores. I'll warm up the aluminium first to ensure a tight fit. Then I'll finish bore the holes to 6mm dia. to suit the crankshaft and the other end to 5mm dia. to fit the gudgeon pin.

A last minute decision

2009-01-25T16:18:00.009Z

The weather forecast for today was really poor, and it turned out to be pretty good, so I took the decision, bit the bullet, grasped the nettle, and went flying. The wind was from the South at around 6mph and later increased to 10mph. Its what I consider the limit for comfortable flying. Later still it decreased to almost zero, and stayed like that for most of the day.

I took both trainers, ended up flying only one of them, but thats OK by me, though I wished I'd brought the Yak.

Crowded...

It was worth going today, as Ian turned up and flew his Excelsior and F15. Spectacular.

Ians Excelsior

Ians F15 - Sorry about the quality, it was recorded on a mobile phone.

This Also flew this afternoon, powered by twin Irvine 30s.

There'll be no flying this weekend. Have you seen the weather forecast?

2009-01-23T18:29:00.017Z

High winds and horizontal rain, sleet and hail. Just as well, I can get on with my engineering project. Today I've made a fixture to hold various sizes of conrod and I've set it up on the rotary table to machine one of the conrods for the KT120fst.

For the conrod I'm currently making, a 6mm dowell is required to locate one end on the centre line. For the other end a dowell with a 10mm diameter is used to locate in the slot of the fixture and a 7mm diameter to locate in the big end of the conrod. So now I can machine various sizes of small end/big end/hole centre combinations.

Fixture for machining conrods

The process begins

...And I've made a start on machining a conrod.

...And I've finished the crankshaft...

Alignment and concentricity end to end is a lot better than expected.

More next time.

Its Sunday and guess what?...

2009-01-11T17:47:00.020Z

...Its blowing a hooley. This is the first day for weeks where the weather has been too rough to fly in, and today is my only day off work. Oh well, its to the machine shop today. First job was to weld some extension tabs to the baffle plate on the inside of our multi fuel stove. It would occasionally fall down onto the hot coals and I'd have to let the fire go out before I could refit it. Hopefully this will stop this from happening.

Our multi fuel stove - repaired.

I've not done much to the engine over the last few weeks as I've been doing other things (Christmas etc.) however today I've had a go at the rear end of the crankshaft, and formed the shape of the counter weight. I still have to drill and tap the clearance hole and M3 thread for the grub screw, then this part will be finished.

First step is to set up for drilling 3mm holes to form the corner radii

Sorry, they're a bit out of focus - trying too hard to get the detail in.

This unusual clamping method was the best way I could devise to hold the part firmly enough to machine into the 3mm holes.

Using the unusual clamping method to mill the 109 degree angle set up using slip gauges.

Sorry about the focus.

Back from the Christmas holidays.

2009-01-04T08:53:00.011Z

Trust you all had a great Christmas, and here's wishing you a Happy New Year. Check out my other blog to see what Lin and I were doing.

Yesterday I was in the machine shop and I fitted the present Lin gave me for Christmas to the Milling machine. I then proceded to set up for milling the other counter balance weight as I did on the front part of the crank shaft. I've only done the setting, I've not cut metal yet as there were some dimensions I needed which were omitted from the drawing.

Those dimensions have now been added to the drawing, but today I'm going flying. More later...

OK its now later, and a great afternoons flying. There was no-one there, and the weather was very dull and the temperature was 1.5C, but the wind was non existant, well maybe a slight air coming from the SW. I took the two Sunbeam Trainers and flew both. One distinctively flies better than the other and I can only put it down to the slots in one of the wings. They don't work. I've been meaning to cover them up for ages but I've not got round to it yet.

No more blogging 'till the New Year

2008-12-20T14:24:00.003Z

Which leaves me to say have a Merry Christmas and Happy New Year, and thanks for watching this space in 2008.

A great flying day so no engineering.

2008-12-06T15:54:00.006Z

I took my time preparing stuff this morning, and until very late I was undecided as to which aircraft I was going to take. Finally I chose the Sunbeam and the Yak54. Both flew superbly although starting was a little more difficult probably due to the low air temperature, after all it is winter. At this time of year I tend to use fuel with 5% nitromethane mixed in to help with cold starting.
Met Geoff at the airfield and he brought along his Mustang which was developed from a trip to Cornwall earlier in the year. That's another story.
All in all a lovely day, wall to wall sunshine, and just a light air moving from the North East.

Yak54 in the late afternoon sunshine.

Geoff with his Moki powered Mustang. The tail wheel bracket failed just before this picture was taken, and that curtailed its flying for the rest of the day.

More on the Crankshaft

2008-12-05T16:53:00.016Z

A day off work, and as the weather forecast is better tomorrow, I'm in the machine shop today.

Finished the front crankshaft part, see pix below:-

I've made a start... To give you an idea of the scale, the 3 jaw chuck is 80mm dia.

A 6mm dia. pin is used to aid setting.

Nearly finished, just the 3.1mm dia. clearance hole and M3 thread to be cut.

Finished and assembled to the centre web with an M3 grub screw.

The hole is clearance size down to the centre and threaded into the 6.0mm hole where the centre web assembly is clamped with an M3 grub screw. Sorry the photo is a bit out of focus, I wanted to get as close as possible to show greater detail.

Flying tomorrow - with a bit of luck!

What did I say?

2008-12-01T20:01:00.002Z

I was spot on yesterday when I said today the weather would be glorious. Its been wall to wall sunshine and light winds all day - aaargh!

No flying again today...

2008-11-30T08:52:00.015Z

...but you wait, tomorrow will be glorious when I'm back at work - 'hit happens, aaargh!

So, into the machine shop for some more exciting swarf making. This engine I'm building is my own design, and I'm drawing it up on AutoCad before making the parts. Occasionally I have to go back to the drawing board to make alterations to the drawings because in practice, sometimes things don't quite turn out as you'd expect. Its called research and development or R & D. The engine I've named, the Ketro KT120fst. is 1.2 cu.in., 20cc swept volume and about 22cc full capacity. Its a horizontally opposed twin cylinder four stroke engine also known as a "Boxer".

Centre drilling position for the crank pin.

Having drilled the hole its now ready for reamering.

Finished, and its a good fit.

All the bearings arrived this week, so now I'll be able to finish the diameters on the crankshaft parts, as I will use each bearing as a gauge to test the fit.

All the parts together, nearly finished. Just the counter balance to mill and the holes for the clamping screws.

And yet more engineering

2008-11-24T21:21:00.019Z

It looks like this is going to be the norm for at least the rest of this month and probably well into December as the weather situation is leaving a lot to be desired. Even the long range forecast doesn't look promising. Anyway it gives me a chance to get on with the Winter project. I'm hoping to have this engine fitted, working and flying early next year. No pix today, (sorry) but I've started on the rear part of the crankshaft. After I'd nearly finished it, it didn't look right so I had to do some cross referencing with the other drawings, and indeed I found an error. Having now corrected the error I can proceed with the part. Luckily nothing was spoiled. The other thing is I've ordered all the bearings for the engine. Six in all, but one size was not available in britain (would you believe it?) so I had to get it from Hong Kong of all places. Then I had to buy ten and I only needed three. Hey ho!
Soon I'll order the cross helical gears for the gearbox. These come in mild steel and will need to be case hardened. The supplier could do that for me but the extra cost makes it more than prohibitive, so I'll do that myself. It was successful on the KT54fs I made earlier, so it should be OK for the KT120fst too.
More on Sunday 30th all being well.

Very bad weather all week-end - NO FLYING...AGAIN!

2008-11-23T17:20:00.011Z

So more engineering. I've made a start on the crank shaft front part. All the diameters are turned and the M6.0 hole has been tapped. Its now ready for parting off. I'll do that with a hacksaw, and although this sounds a bit crude its my preference in this case as the part protrudes out of the chuck by a long way. Parting in the conventional way would be a bit risky.

Notice the DTI on the cross slide to assist with accuracy.

Turning the 10.0mm dia. Revolving centre for support and helps prevent chatter.

Ready for parting. Note the M6.0 thread has been cut.

Oh! yes, and I've cut the flats on the central web as seen in the log below.

More engineering today

2008-11-15T17:00:00.012Z

Made the central crank web this afternoon, turned up a piece of mild steel to 29.5mm Ø, drilled a 6.0mm Ø tooling hole in the centre, and parted it off to 3.0mm thickness. Placed it in a 3 jaw chuck mounted vertically on the milling machine, and clocked the tooling hole to centre it on the machine. Drilled and reamered 2 holes through 6.0mm Ø in 'Y' +10.0mm position and 'Y'- 10.0mm position.

Then I cut off two pieces of 6.0mm Ø silver steel to 17mm length, and silver soldered them into the central web. I've not cut the 3.1mm wide flats yet, that'll be done the next time I work on it. Check out the pictures...

No flying today, poor weather conditions

2008-11-02T18:27:00.010Z

The wind was blowing a hooley today, so I spent the day in the machine shop. Finished the finning on the cylinder heads, and now I'm thinking about the crank shaft design change. I have to enable the use of one piece conrods due to lack of clearance on the lower parts of the cylinders and the pistons. This will necessitate the design change from a one piece shaft to a three piece.

Some pictures as promised

2008-10-25T18:24:00.014+01:00

After a bit of household maintenance this morning I managed to get out to the machine shop to do some work on my KT 120fst engine. I've been looking at the Cylinder Block and thinking that it probably won't make as the design is at the moment due to the large size of the big ends. So I'm thinking about making the Crank Shaft in three pieces to enable attachment of one piece Conrods. Anyway, enough of that, today I set up the mill with an angle plate and a fixture to cut the fins in the Cylinder Heads. Take a look at the photos, they can explain far more than I.

Angle plate & fixture mounted on the machine bed

Close up of Starboard Cylinder Head prior to finning

Cylinder & Crank Case with Sleeves fitted

Cylinder & Crank Case with Port Head & two Pistons

1.5mm slitting saw used to create the cooling fins

A late session

2008-10-24T20:56:00.012+01:00

Went flying today, though I didn't go until late in the day, had some jobs at home to do first. Arrived at Westonzoyland Airfield at around 16:30hrs. Light winds from the West and glorious sunshine - and there's no-one here. Only brought along the yellow/red Sunbeam and the Pico-Jet. The replacement li-po charger arrived this week, and I'm now about to test it out having had a flight late this afternoon. Oh! yes, and the bearing fell out of the motor again. The Super Tigre engine in the Sunbeam ran well today although it was a bit difficult to start. It seemed I couldn't get enough fuel through by choking so I primed some fuel directly into the carburettor, and then I flooded it, but once it was running it was quite reliable in the air.
As the sun went down the wind dropped and my last flight was dead smooth, even at very low height. Flights like this are rare and are the most satisfying.
I intend to do some work on the engine I'm building tomorrow (Oh! did I not mention that?), so I'll try to include some pictures.
The weather forecast for tomorrow is crap (light rain and sixteen mile an hour winds) and I have to work on Sunday, so that's it for this week as the clocks change early Sunday morning. Winter has arrived.

Early Morning was Best

2008-10-19T13:34:00.008+01:00

Yes, the weather took its toll on todays flying. I arrived at the airfield at 09:15hrs and it was dead calm. By 10:00hrs it was getting windy and by 12:00 it was rough. Took both trainers again and flew both and I flew the Pico Jet but there is a problem with the motor, there is excessive "slackness" in the bearings so I only had the one flight. The Super Tigre engine in the trainer is behaving better so I wonder if the problems were related to running in. I'm still a bit disappointed with the power output so I might experiment with some different glow plugs, fuel and propeller combinations. By 12:30hrs I'd had enough, the wind was cutting through me and I could feel my core temperature was beginning to fall so I packed it all back in the car and went home. At least I've had my fix for the week.

A Good Sunday

2008-10-13T07:18:00.006+01:00

Probably one of the best flying Sundays this year. The weather has been amazing for Autumn, today starting off foggy but by 11:00hrs the sun burned through and resulted in a hot day. Took both trainers, the Pico Jet and the Yak 54 to Westonzoyland. A lot of pilots turned out to fly although I suspect the early fog put some off. I meant to have covered the slots in the red and white wing this week, but I've been too busy with other things. Thinking on (careful), perhaps I should try covering just the white section. Maybe all the sections are too much - hmmm. Worth a try.
The Yak was a bit unnerving today, my fault, there were a lot of other aircraft flying at the time and I was trying to fly Knife Edge. Got myself in a disoriented state, and near panicked when I wasn't certain which way up the aircraft was after I leveled the wings. Upright - phew! that was close. Time to land, too many other aircraft flying lead me to distraction. Or should that be destruction?.
The Pico Jet performed well, but is a bit lively on the controls and the motor is continuing to resonate at certain revs. Still not sure whats causing it. I'll check the propeller balance and also see if the motor does it without a propeller. With regard to the "lively" bit I think I need a little weight removed from the tail end of the aircraft. I always reckon to do it this way rather than take the easy option and add weight to the nose. I can't remember the last time I added weight to the nose of an aircraft. The need for this change is as a result of the use of Li-po batteries replacing the much heavier Ni-Mh.
The Super Tigre engine in the other Sunbeam is still playing up, I've been experimenting with the carburettor, but with little success. The spray bar position is adjustable, and its important (allegedly) to get it right, and I've found it does make a difference when its adjusted, but it doesn't seem to stop the revs from surging at the top end. I've found to stop it, I need to richen it up a lot but on closing the throttle and opening up again the engine runs extremely rich and needs to be leaned. There is nearly a happy medium I can use but it ain't quite right yet.

Its not likely there will be any mid week flying from now on untill the clocks change again next Spring, although I might be able to get the odd Monday in as shift work and weather allows.

Last of the Summer Flying - Revisited

2008-10-09T05:16:00.000+01:00

I lied about the previous entry. Who would have thought the weather would have been some of the finest of the season at this time of the year. Wall to wall sunshine this evening. Last week I was on holiday and it rained every day, sometimes horizontally. This week there's hardly been any rain at all. Just my luck! Never mind, had a few flights with the Sunbeam trainers and I'm not happy with the slots and flaps on the red and white wing, so I'm going to cover them over. Thought I'd try inverted flight, and it was hopeless. Full down elevator required and still the aircraft decended. Those slots have got to go.
Two flights with the Pico Jet and as always good entertainment. Motor is making some strange resonating noises at certain revs. Don't know what this is all about, may need investigating.
19:00hrs., and its too dark to fly. Clocks change soon, Winter's on its way!

Last of the Summer Flying

2008-09-24T21:01:00.000+01:00

This is probably the last of the mid week flying sessions. I took the Pico Jet and the two Sunbeam Trainers to Westonzoyland. The weather was a little windy, about 5 mph gusting to around 10 mph, and 95% cloud. Had two good flights with the PJ, and a flight with the 40 powered Sunbeam, and two flights with the 25 powered Sunbeam with the new wing. (Flaperons and slots). This behaves a bit strangely when flaps are deployed, it seems to become a bit unstable. Some more testing and investigating required I think. It got too dark to fly by 19:15hrs., but there was a beautiful sunset, shining scarlet through a break in the cloud. Dam! I forgot the camera.

Sunday 21st September. A bad omen?

2008-09-22T09:43:00.000+01:00

Arrived at the airfield at around 10:45, opened the tailgate of my car and my bottle of fizzy pop fell out onto the tarmac and squirted some of its contents everywhere. Was this a sign of things to come? Anyway, got unloaded and took the car to the car park, and walked back to the pits and began assembling the aircraft. First up was the yellow Sunbeam after tuning the engine carburettor after its ultrasonic clean. Once tuned it seemed to be a bit more settled, but was still a bit below par on power. I would have expected 12,500 rpm on a 12 x 7 prop out of this Super Tigre 40, but it was struggling to get 11,000. The flight turned out OK though. The Sunbeam in the picture above has a new wing equipped with slots and flaperons, untested at this time.

Next up, the Pico Jet. I am amazed at the power of this little toy, and the flight length is incredibly long with the 2200mah li-po battery. This is where I discovered I had a problem with the new charger not charging correctly. I seemed to charge cells 2 and 3 OK but didn't charge cell 1 at all. This was confirmed when I tested the battery with a digital multi meter, in fact I found also that cells 2 and 3 were not fully charged. I've emailed the vendor.

Then I thought I'd chance the Yak54. First flight was fine, no problems, but on the second flight the canopy and cockpit decided to part company from the fuselage and ended up like a busted bag of flour on the tarmac. Highly annoying as it was a new one I'd just purchased recently, to replace the one which the same thing happened to in Cornwall back in August. Managed to land the aircraft safely, though. That bottle of pop was trying to tell me something after all!

Wednesday 17th September

2008-09-18T20:53:00.000+01:00

The day looked dull all day, in fact it rained during the afternoon, but it soon dried up by 16:00hrs. Arrived at the airfield where fellow members Jim, Paul and Bob had already been flying. My first flight was with the yellow Sunbeam with Super Tigre 40. Having some problems with engine surging at full throttle and richening the mixture cured it although after closing the throttle and opening it again, it went so rich it wouldn't be able to take off. More tweaking improved the problem and I managed a flight.

Next up was the Pico Jet, and Jim said he'd join in with his PJ. So we launched together. I was well chuffed when I beat Jim on top speed and duration. These Li-Po batteries are the bees knees, I can fly my PJ for around 20 minutes and the top speed is phenomenal thanks to a 1700kv out runner motor. Towards the end of the flight I encountered seemingly a minor problem, when I accelerate the motor to full revs the plane drops its nose a lot and after I'd landed I found out why. The motor mount had come unglued and was hanging loose. I couldn't believe the PJ was still in one piece. Lucky!

Back to the Sunbeam Trainer and a bit more tweaking, and some more flying. Its still not right so I'm going to dismantle the carburettor and place it in an ultrasonic bath with some ethanol. Watch this space...

CAP 21 Crash!

2008-09-15T18:22:00.010+01:00

Sunday 31st August.
Flying at Westonzoyland as usual, and had a bit of an accident with the CAP 21. The intention was to half roll to inverted, then half loop, but it got as far as the half roll, and kept on rolling, throttle wide open, vertically into the bean field. Oh! sh!t. Walked over to the spot and with the aid of a pair of walkie talkies and a fellow club member who spotted the point of impact. I walked straight to it, and sure enough it was in bits. I had to dig the engine out of the ground, and after further examination, I discovered it was fine, not a mark on it. Its rare you find anything wrong which could indicate a fault in these cases and this was no exception. The radio was working perfectly. I sent off all the radio gear to Horizon and they very quickly found a fault in the transmitter. The RF output was low, so they changed the RF board. Now I find I have 60+ paces of range compared with 32 previously. But I'm not going to take any chances, so I'll only fly aircraft I can afford to lose for the time being.

Sat 13th September, Westonzoyland.

2008-09-14T05:39:00.000+01:00

Fine weather today, sunshine and light winds from the WNW. Flew the Pico Jet now fitted with uprated out runner motor, ESC and li-po. Superb performance, even vertical. In the IC section, I flew the Sunbeam trainer with a Super Tigre 40 engine swinging a 9x6 APC prop. Yes, I know its a bit small, and I've ordered a 10x6 and a 10x7 Master Airscrew. Should be here in time for my four day weekend. The engine is about 20 years old and never been used, so its "running in" rich settings for the time being. One thing I noticed is how noisy it is. I guess it was made before the surge to reduce engine noise.

2008-07-28T07:27:00.000+01:00

Sunday 27/7/08.

Probably the best day of the year so far for weather and flying. My 2.4Ghz receivers returned from Horizon earlier this week and I've fitted one in the Sunbeam, and one in the Yak54. Flew both today, and no problems - excellent.

Off to Cornwall next weekend, so I must get the other 2.4Ghz receiver fitted in the CAP21 before then. Also I'm still waiting for some Li-po batteries, a charger,motor and an ESC to arrive hopefully this week, so I can fly the Pico Jet.

Flying Now

2008-07-07T20:27:00.001+01:00

Current models are Sunbeam trainer, I've had this model for years, Its nearly been shot down twice by someone else switching on their transmitter on the same frequency, but I somehow managed to maintain control and land safely. So now I've finally invested in 2.4Ghz. Powered by an Irvine 25 and guided by Spektrum DX7. My Yak 54 is a fairly new model, laser sculpted by Seagull Models, its powered by an SC108 which is more than ample for vertical performance. Guidance is by Spektrum DX7 with 6 servos. I've experienced a few problems with this engine with regard to keeping an exhaust muffler on it. It just will not stay on, so I've wired it on just in case. Oh yes, the carburrettor has a design fault. There is a reducing sleeve in the barrel which at the fully open position will engage with the body casting jamming the throttle wide open during flight. Spending 30 minutes flying around at full bore is no fun, and landing dead stick with this aircraft is difficult. It does'nt glide far and if you need to turn it drops like a stone due to the tapered wing.

The CAP 21 is 60" span aerobatic aircraft for a .40 two stroke to .60 four stroke engine. I used to fly this with an OS .61 four stroke, but it was 'orrible. It kept changing its trim settings during flight and landings were less than graceful. Currently its fitted with a four stroke engine I designed and manufactured myself, the Ketro KT .54fs. A change of radio to Spektrum with digital servos has eliminated the trim change problem, and the engine has performed faultlessly for over a year. I'm well pleased.

The Pico Jet is a small electric delta. I use 8 x Kan 1050 cells to power the 400 size motor and pusher prop. Guidance is by Spektrum using the AR6100 receiver.