Wednesday, 22 March 2017

Official ICAO code for Silence Twister

After some work with the ICAO database people I have secured an official code for the Twister.

When filing a flight plan from now on use the code: TWST 

Previously you would have had to use the code: ZZZZ and put TYP/SILENCE TWISTER in the Extra Information section of a flight plan.

Hopefully air traffic will be a little less confused by us in the future.

As you can see they should no longer ask how many POB (Persons on Board) as the description shows 1P (one place).

The confirmation email from the ICAO database is below.

Dear Mr. McKee,
I would like to inform you that the ATDSG (Aircraft Type Designator Study Group) has now completed its review of all the material that you have presented and has allocated the following aircraft type designators TWST for the Silence Twister model. This information is now registered into the Aircraft Type Designator (Doc 8643) electronic database and will be sub sequentially published in the next edition of Doc 8643, which is scheduled for April 2017. I would like to personally thank you for bringing this model to our attention so that it could be registered into Doc 8643.
Manufacturer/Model                    Designator                         WTC                     Description
SILENCE Twister                              TWST                                   L                            L1P
Best regards,
Steve Laskie
Air Navigation Planning & Support Officer
OPS Section
International Civil Aviation Organization

New Camera mount, oil filter, aileron pushrod fairings and SPOT Tracker.

As you will see from the below screenshots and video links, I've built a new camera mount which now gives a forward view from the tail.

It seems to work okay but I think the prop wash is causing it to vibrate a little bit which sometimes makes the sky 'swim' with distortion as the cameras stabilising is pushed to it's limits.

This vibration is most likely coming from the plastic mount stalk itself as the carbon bit's I've made are very stiff. Nothing I can do about it really. Will see how it goes and maybe think of a better solution at a later date.

I also finally got around to fitting the aileron pushrod fairings - which are a Pete Wells mod. Fairly straight forward to fit, just use double sided tape (the good stuff - 3M). As I'm paranoid they could come off I also used Duct tape as a back up to secure them in place.

I've also invested in a SPOT Tracker and found a good place to mount it in the cockpit. The unit must have a good view of the sky to keep GPS coverage. It also needs to be removable so a simple velcro strap with foam underneath has done the trick. I will use it on any long trips and obviously it will be very handy on the Oshkosh trip - a very good way to track exactly where you are. It updates it's position every 5 minutes. There is also an SOS function on it which alerts the appropriate authorities so it provides a good backup to a PLB/ELT.

Nice of SPOT to colour coordinate their unit with G-FUUN too. :)

Regarding the oil filter - I have sent it to Patrick at UL Power for a closer analysis as Patrick admitted that it had more metal in it than normal. I will keep you posted as to what he says.

Now for some video with the new camera mount. 

A 4 point roll:

And some sustained inverted:

4 point roll - still from video link above

Inverted - still from video link above
SPOT Tracker mounted on top of headrest

Colour co-ordinated Tracking device.

Aileron pushrod fairing

Double sided tape on the flanges and duct tape as a back up.

Front view. I have not noticed any performance benefit.

Rear tail camera mount made from Carbon. I laid up the curved portion directly on the tail then bonded on and reinforced the flat plate section later. Thin foam on the inside is to stop the paint getting scratched. The mount itself is 3M stuck in place and then riveted as a backup.

Mount in place on the tail.

Closer look. I think the vibration is coming from the flex in the plastic stalk part of the mount.

Looking forwards.

Wednesday, 15 March 2017

FUUN times

Video of a flapless takeoff, just to see how it feels. Doesn't take much more runway than with 10 degree takeoff flap. (I'm holding it down for the showboat ending after lift off.)

More serious stuff coming soon.

Friday, 10 March 2017

Clipped wings no more

I got a phone call today from the LAA to say my Permit had arrived back from the CAA!

They posted it to me today so I should have un-clipped wings by Monday.

The world is now truly my oyster.

Monday, 6 March 2017

15 hr maintenance on UL engine

The 15 hour maintenance is all done and there were no problems.

As you will see below the oil filter had a fair load of crap in it.

The cylinder head torques were ok. 

The tappets all needed adjusting (tightening). The inlets were pretty close to correct but the exhausts were all loose. I put a pen mark on the top of the starter ring gear and alternator fan to show where top dead centre is as it's impossible to see the factory mark when it is in position vertically. 

I gave it a test run on Saturday and all was well.

Still waiting on the full Permit to Fly to arrive - I expect it will be another week or so.

Draining the oil - when I lifted the tail quite a bit more oil came out. It's a good idea to do this as the drain plug is positioned towards the front of the sump and if the tail is down you won't get all the old oil out.

Adjusting the tappets.

This was the worst section of filter.
The whole filter element. Click to see larger view.

Saturday, 25 February 2017

Destination Duxford

A great day out yesterday.

After the chaos of Storm Doris the day before, Friday dawned clear and calm.

If you've been following this blog all along then you may remember me testing out the Twister in FSX Flight Simulator about 5 years ago. See January 2012 for the post. The 'testing' was done at Duxford and now I've flown in there for real.

This was my first time landing and taking off from a hard runway with G-FUUN and I have to say it again - this is a viceless taildragger - very straight forward. Just had to be cautious of my poor turning circle when asked to backtrack on the main runway - so a swing to the left a bit before turning right was the answer. It was slightly more squirrelly on take off - yawing left and right than on grass but nothing too bad.

Some very good news - the LAA has approved the testing paperwork and has sent off to the CAA with a recommendation for a full Permit to Fly. So I've just got to be patient now and wait the 10-14 days for that to come back.

In the meantime I will use the time to perform the initial 15 hour engine maintenance.

A few of other things I forgot to say in my last post were that the cabin noise is indeed low - as I thought it was - 88db to be exact. This is a full 10db quieter than the Pipistrel and Piper I was flying before.

The other thing I did was climb up to 14,000ft - to see if it would do it first of all and then to see what kind of cruise I could get out of it at that altitude. Cruise was 106knts indicated which is about 130knts TAS - so even if I have to file IFR for the Greenland Ice Cap crossing I can do it - they give a minimum based on the QNH that day and it can be as high as FL140. I see that a guy who flew his RV8 back from the USA to the UK did a VFR crossing at 11,500ft. So that is all that is needed for terrain clearance but it would be good to have the flexibility of being able to file IFR should I need to fly above some cloud.

And finally, lately I've kept the cowl flap closed for the entire flight. Temps are well within range and even doing sustained climbs and aeros the oil does not get hotter than 95 C and is typically in the mid 80's. So the cowl flap is useful to keep the oil warm in the Winter and for high altitude cruising.

Compare the wing above to the Mk24 Spitfire here

Concorde from below

Concorde flight deck

TSR2 and Vulcan (amongst others)

Spitfire and ME109 Buchon

The seemingly-never-to-be-finished Beaufighter.

Sally B/Memphis Belle

Winter maintenance on a Mk Vb Spitfire and P-40 Tomahawk

In good company

Departing. American hanger on the wingtip.

'Testing' G-FUUN in FSX 5 years ago.

Yesterday, the real thing.

Friday, 17 February 2017

More on the Electric Twister

A good article that goes into some more detail about the electric Twister, which they are now calling the aEro.

From the text this is most interesting!

"Today, the aEro rolls at 270°/second, but an Extra-type wing is being designed to reach a roll speed of 400°/sec. Other developments include a sub-fuselage concealed pod for a thermally boosted battery charger for positioning flights."

Not sure I agree with the 270 degrees a second figure as it is more like 90 degrees a second on a standard Twister. But that new wing sounds interesting.

When aeros guru Alan Cassidy tested a Twister some years ago the only thing he found lacking was the roll rate - and suggested ditching the flaps and going for full span ailerons.

Yesterday I was doing some ballistic rolls (rolls with 0G on a parabola type curve) and found they took 4 seconds, so the 90 degrees a second figure is accurate.

Link to the full article here:

Wednesday, 15 February 2017

Aeros and ASI Calibration

All is going well and I'm now getting into aerobatics which is what the Twister is designed for.

I've entered into the Club competition this year and have started to put the sequence together already. Although it is full of errors and my G-tolerance sucks at the moment. Anyway lots of time to get those things right as the comp is not until the end of May.

I expect to come last in the comp as the others all fly Extra 300 and 200 aircraft - which is a bit ridiculous as this is supposed to be for newcomers to the sport. Anyway it is a good disciplined way to get better at aeros rather than just going up and mucking about.

A short video of some aeros here (with a little cloud play at the end):

I also did a calibration of the ASI's to see how accurate they were. See the results below. I probably did not fly such an accurate sequence here as the altitude varied and the day was not exactly calm. Even so in the mid speed range it is quite accurate. The Dynon and Winter both agree with each other to within a knot most of the time - until either extreme of the speed range when they get about 3 knots out.

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!