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: https://youtu.be/fweoCIosUuY

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.

Landing

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!

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