Spitfire

Seen at Fairford and (possibly) Cassiobury Park on 20th/21st July was this MkXVI Spitfire from the Battle of Britain Memorial Flight, here in commemoration of 617 Sqn. Dambusters 70th anniversary.

Also from 617 Sqn...

Panavia Tornado

It's now an ornament.

Yes, sadly the KT120fsT has died. During yesterday's testing at near full throttle there was a sudden loud clatter shortly ending in silence.

Another broken crankshaft

Testing was going really well, RPM was up to 6400 at maximum throttle and idle was around 1800 on a 16 x 8 prop. The cool cylinder was beginning to heat up as running in increased the seal in the combustion chamber, although idle to full power was slow. The new carburettors were performing well after their modifications and I think further improvement could have been made to the mixture control by increasing the diameter of the air bleed into the barrel at the tick-over position. Oh! well, maybe another day, in the meantime I'll reconstruct the engine and it'll take pride of place on the mantelpiece. (As a reminder to me not to do it again).

Too much noise again

Well, It seems we have someone who wants to be rid of the Flying Club at Westonzoyland. However this came in from the local Environment Officer:-

"I am writing to confirm the findings after the site visit made by myself and Mr Coles on May 31st. On that date (between 11:15 to 12:45) several model aircraft were witnessed flying including ones powered by propeller and by jet engine.
Currently based on the noise witnessed at the time of our visit there is insufficient evidence to demonstrate that a statutory nuisance exists and I have advised the complainant of this.
On the day of our site visit some planes were witnessed coming close to the no fly zone, however we were later informed that this was to demonstrate the noise at the closest point. As this latest complaint seems to have allegedly been caused by one of the propeller powered aircraft flying into the no fly zone could I therefore request that club members are reminded of this zoning.
As discussed at the time of our visit we will continue to investigate this issue if we get further complaints and where necessary liaise with yourselves to resolve any issues that may arise.
Thank you for your continued cooperation on this matter."

Problem solved? Let's hope so.

Success - allbeit limited.

I'm still struggling with the carburetor and the design in the previous blog won't do. The bends in the pipework from the carburetor to the cylinder heads are too tight and it's not possible to make them. So this time I've gone for twin carbs and they each attach directly to the cylinder heads.



It works! That propeller is an 16 x 8 Master Airscrew

After a lot of thinking and research on the internet I thought that the fuel was not burning correctly. I've put it down to the glow plugs not protruding far enough into the combustion chamber so I've made the plug recess 2.3mm deeper on the outside.

Seems to be more reliable and controllable with two carbs.



There is still some work to be done, it won't run to full power, it seems to lean out so I think perhaps I need to enlarge the fuel passages in the carburetors. This was probably the cause of the tightening that occurred at half throttle where the air flow increased and the fuel flow stayed the same. The result was a hotter burn and swelling of the pistons and creating more friction = more heat = more swelling = more friction = more heat. You can see where I'm going with this. I closed the throttle at this point and the engine stopped abruptly. I turned it over by hand and it was tight so I let it cool down and it became free again. If I can cure the the fuel starvation I think the overheating problem will be solved. I'm pleased with today's testing, a good result.

Too much noise

I visited Westonzoyland Airfield on 20th April and took my Pico-Jet and Yak 54 to fly. Just before lunchtime one of our club members left but came back a few minutes later to explain that he'd been confronted by a local resident on the subject of noise. It seems very large aeroplanes are flying very close to a residential area disturbing the occupants. (Note the word "Model" is absent).
WATCH THIS SPACE!