Saturday, 24 December 2016

Flight testing

We've been very fortunate to get some gin clear days this December so quite a bit of the flight testing has now been done.

The LAA minimum is 5 hours of flight (including one 2 hour flight) and 15 take offs and landings before completing the test schedule paperwork and applying for a full permit.

G-FUUN has done 4.6 hours and 14 take offs and landings to date. So one more flight may be enough to complete the testing.

Chris has done 3 flights and 1.6 hours. I've done 3 flights and 3 hours.

On the last flight I 'bashed the circuit' and did 8 take offs and landings. 

I have to say that G-FUUN is a very well behaved girl, it's the easiest handling taildragger I've flown.

The undercarriage does not have any dampening so tends to bounce you back up into the air a little bit if you touch down with any kind of vertical component.

Once the tailwheel is on the ground it tracks straight. I've been 3 pointing it and this seems to be the best way - certainly before tackling a big crosswind that is. I will probably revert to a 'wheeler' landing when the time comes to fly it in a strong crosswind.

On Chris's advice (and example) I've also not been getting the tail up too high on take off (as I was doing when high speed taxiing). Just let the tailwheel get about 20cm off the ground (once you have rudder authority) and let it fly itself off in that attitude when it's ready.

All has not been straight forward though - on my second flight after performing a long climb of approx 6 minutes (as part of the testing schedule),  I noticed when leveling off that the Voltage had dropped down from it's normal 14.5 to 11.8. I immediately headed straight back to the airfield at high altitude. After 10 minutes it dropped to 11.7 volts and so I joined the circuit and got back on the ground. 

I didn't fancy my second ever landing being a dead stick one.

As you may already know the UL Power is an 'electric' engine. That is, it needs an electric supply to run both the ignition and fuel pump. As the Alternator was not charging the battery then the plane was running off the battery only. It's only good for approx 40 minutes in this condition before the voltage drops below 10 on the battery and the engine will stop.

So I grounded the plane until I found out what the problem was.

After checking the Dynon was not giving spurious readings by wiring up my Multimeter to the battery directly and running the engine - sure enough the Dynon was correct and the voltage was dropping slowly as the engine ran.

Off came the cowlings and it didn't take long to see what the problem was. See pics below. The Molex connector that connects the wires from the Alternator to the Rectifier/Regulator had melted (due to that long climb and being too close to an oil hose connector - which had got up to 95 degrees C +).

So I've cut out this Molex connector completely and just used butt splice connectors and routed these wires up and away from any heat source.

Once that was fixed and ground tested we were back in business.

Chris flew the complete aerobatic schedule - as part of the testing - on Tuesday.

He gave it another glowing report and finished up by saying "You've got a Rolls Royce aircraft here!".

He also said it was much more slippery than Pete's Twisters - it accelerated quicker and retained its energy better - all good news for aeros.

Pete has challenged me to a 'race' next year to see once and for all if a fixed gear is quicker than the retractable. It will be interesting to see what happens in that side by side test. 

The only issue from the aerobatic schedule was fuel venting out the vent line on the downline of the stall turn - see video below. Chris is not used to this happening so I will need to contact Pete to see what's going on and if there is a fix for this.

Video of the aero schedule here:

It is recommended to watch this on a laptop or desktop as the annotations do not show up on mobile or iPad. 

G-FUUN is now up the back of the hanger and put to bed for January as I am away in New Zealand and Asia and won't be back until February.

So this blog will be a little quiet until mid February.

I intend to continue posting information as and when it arises and if I think it's worth sharing although it won't be the regular weekly or fortnightly updates that you are used to.

Happy New Year to everyone and here's to a FUUN filled 2017!

Sky reflections on my 2 hour flight

Chris inverted as part of the aerobatic schedule

Chris just about to set off on the Aerobatic Schedule flight. (I used to fly the Piper in the background.)

High speed fly by from Chris.


Making the most of this good December weather.

I've gone the 'Adrian Hatton route' of attaching the gear leg fairings to the fuselage with self tappers and then taping up the gap and fittings and then just leaving the bottom edge free to move on the gear leg. (Only good if you're not rigging and de-rigging all the time).
P-clip to secure the wing pins - nice to know they won't come loose whilst performing aeros.

The melted Molex connector.

Ditto. The offending article has now been removed from the system.

Wires now connected with butt splices and re-routed up and away to avoid any heat effects.

Max RPM. 149 knots straight and level (cowl flap closed). Note: throttle is not WOT at this speed - it is retarded to about 85%. Ignore the EFIS it has not had it's zero pitch set yet.

High speed cruise with cowl flap closed. 130 knots.

Cowl flap open and a bit less revs - maybe even in a very slight climb here. 125 knots.

Figures from straight and level. Note two sets of figures for cowl flap open and closed. Oil temp goes up by 5-10 degrees with it closed. 2650 is a sweet rev setting for the engine.

Climb performance. Not sparkling but to be expected as it is G-FAAT after all.

G-Meter after Chris' aeros schedule. +4.3 and minus 1.9. It's had a proper work out!

Tuesday, 13 December 2016

Sunday, 11 December 2016

First flight(s)

Today was the first flight(s) of G-FUUN.

I'm happy to report all went very well.

Chris did 2 flights then I did one. Each flight was about 20 mins.

Chris said that it flies hands off - no trim adjustment needed. I concur.

All the T's and P's are green in flight.

I think it will be okay to close the cowl flap in the cruise as the oil was 80 C with it open. We left it open today but maybe I will try it out on the next flight and see how it goes.

Cruises at 125 knots at 2,800 rpm. Pete Wells' Twisters only get between 110-115 knots at this rpm.

On the first flight Pete arrived in the circuit by coincidence so he formatted on Chris. See pic below.

First impressions are it feels very solid and stable in the air. Not like a light aircraft at all. The rudder is very sensitive in flight though - Chris says it is normal. Something I'll have to get used to. Excellent forward visibility in the cruise and quieter and less vibration than the Pipistrel Virus SW I've been flying lately.

I'm still smiling...

My thanks must go to Matthias and Thomas Strieker for creating such a wonderful machine - it really flies like a dream.

Also thank you to Peter Wells for all his support, patience, knowledge sharing and generosity over these last 5+ years.

And thank you to my family for supporting and encouraging me and listening to me when I had a tale of woe about yet another set back to tell.

A better video is coming soon but in the meantime here is the first take off:
1st take off

Chris on the first flight with Pete in formation

Grinning like an idiot after my first flight

Friday, 2 December 2016

Getting close to that first flight

It's been a good week.

Firstly I dropped off the silencer and pipe to our local guru welder Chris Baglin of Merlin Engineering.

Chris turned the job around in 2 days flat and only charged me £50 which I thought was very reasonable. The work was of an extremely high standard too.

While that welding was being done I took the opportunity to make up some new deflectors for the front cylinders. The previous version - Mark 2 - still did not bring the temps close enough, with a difference of between 10 and 15 degrees from the front to the back (the back being hotter).

So Mark 3 deflectors were made up - these cover almost the entire front half of the front cylinders. I overdid it a bit and now the temps are too hot at the front! But the difference now is only 10 degrees, so I will cut down the deflectors a little bit and hopefully they will be close to 5 degrees difference, which is what I've been aiming for all along.

A chat with my test pilot Chris Burkett revealed that Pete's Twisters have up to 20 degrees difference between cylinders. This can't be all that good for them.

So today with everything back together I did some more high speed taxi's.

See the video by clicking on the link below.

All would be ready for a first flight on Sunday (and the weather looks good too) but Rex my inspector has gone to France this week and won't be back till next Friday so we've lost another week. Oh well it gives me time to thoroughly test this new weld and make sure the exhaust is not cracking again. Murphy's law says that next weekend will be crap weather.

Also I've now been approved by the LAA to help Chris with the test flying. Chris will still be the lead pilot and do the initial flights plus the aerobatic schedule but I should be able to take over after that if there are no other issues.

Mark 3 deflectors - a bit too much as it turns out. Not riveted or RTV'ed here yet.

Beautiful welding from Chris Baglin of Merlin Engineering.

CHT's just after shutdown. Some more tweaks to the deflectors needed.

High Speed Taxiing. (the Video link is in the above text.)