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A big well done and thanks to Chris, Ian and the Ashbourne club for hosting a really enjoyable day’s flying for everyone. This was my first attendance at the event, having only recently moved into the area. A highlight for me was meeting Alex Whittaker, Danny Fenton and Tim Hooper whose writings keep us all well-informed and inspired by their skills and techniques.

Thanks also to Danny and Lindsay for the ace pics of the Jungmeister and Tiggie. The latter is now around 14 years old and on its 3rd motor, 5th battery chemistry (nicad, nimh, saphion, A123 and lipo) and second latex pilot as the original one crumbled. Only the Schulze esc and well-worn airframe are original as the tyre wear and crazed paintwork show, but folks seemed to like its aged appearance, which I’m afraid embarrasses me somewhat as I never seem able to get around to sprucing it up.

Like everyone else the Tiggie, Jungie and I are definitely looking forward to next year’s fly-in with enthusiasm!

Cheers

Gordon

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Gordon, for me the Tiggie was the model of the day. It certainly gave me the kick up the wotsit to get the finishing touches to my DB version restarted, particularly as mine's electricaslly powered, too. It certainly doesn't look 14 years old and you have nothing to be embarrassed about.

One of the things that got me restarted was your advice/information about how the rudder closed loop was supposed to be and I've just made a suitable system which should do the job. As I'm working on a part completed airframe I was given it means a few modifications, particularly as it was the donor's first ever aircraft build!

G;ad you enjoyed the day and I hope you get your gas turbine sorted for next year

Geoff

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Not rocket science, Tim.

It was just that I thought I'd need to make up a system for for a scale(ish) rudder closed loop system with 2 levers, one poking out each side below the front cockpit. Gordon pointed out that a single long lever, pivoted in the middle, works perfectly well and I've made one out of an old piece of glass fibre PC board (I have a lot of that scrounged from my former employer, who shall remain nameless!). It's not finished yet, but I've made the whole thing from my extensive scrap box (also known as my workshop )

I'd been putting off the job but Gordon's advice (and his lovely, medium sized Tiggie) persuaded me to get started.

Geoff

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Hi Guys

Fixed the jet, and took pics of the Tiggie control system. It's sport scale so not an exact replica.

1. Showing link from central aileron servo to aileron pushrod emulating full size setup.

a - rudder bar 01.jpg

2. What's under the hatch. Elevator servo top, aileron servo middle, rudder servo bottom of pic, linked to rudder bar.

a - rudder bar 02.jpg

3. Angled shot showing ail servo and rudder beam mount.

a - rudder bar 03.jpg

4. "L" section plastic fairing over rudder bar end as on real one.

a - rudder bar 04.jpg

5. Rudder cable guide. Nylon-covered fishing trace passes through PTFE tube which is CA'd into bracket, otherwise nylon outer wears off the cable.

a - rudder bar 05.jpg

6. Where all those darned cable go! Best to install the elevator cables before covering so that you can work out where they'll exit through the fabric covering, but just bend ends through ferrules and don't crimp. Then detach cables from elevator end and tuck inside fuz, cover, and then re-attach cables and crimp.

a - rudder bar 06.jpg

7. Cable exits stiffened with G10 "eyelets" to keep them neat.

a - rudder bar 07.jpg

8. Elevator cable guide bracket with PTFE tube protector. The tube is that which comes with Zap CA.

a - rudder bar 08.jpg

9. I thought I'd also show the elevator cable idler bar and 180deg crank operated from elevator servo. The carbon tube and horn are slotted where they intersect, and a small rectangle of tufnol inserted as a key to prevent rotation, before epoxying the joint. Servo pushrod and single-ended crank on right of pic, elevator crank in middle with up and down elevator wires at opposite ends. The crank is installed before covering.

a - rudder bar 09.jpg

Ref the jet, the Hawk's original turbine went for servicing recently, so I'd replaced it with one which had been happily flying in another model. But I but didn't swap over the fuel control solenoid valves from the other model to the Hawk. As the replacement engine was known to be working, and as I thought all solenoid valves would be the same (they look identical), I didn't bother doing a run-up through lack of time. At Ashbourne, I discovered that not all solenoid valves are the same. It transpired that the solenoids in the Hawk were of too low a resistance to work with the replacement engine's Fadec which tried to draw too much current, and declared an "overload" and switched itself off. When I replaced the low-resistance valves with the ones that should have been used, all came right and the jet is ready to fly again with its current engine.

FWIW I measured the resistances of my 3 pairs of solenoid valves. One set was 38 ohms, a second set was 28 ohms, and the "offending" set was 16 ohms. The 16 ohm valves were from a gas-start setup and worked properly with their gas-start ecu. But having upgraded to kero start, the kero Fadecs use higher-resistance solenoid valves. Fortunately, provided I use these low-resistance valves only to work the kero plug, with a low-resistance valve in the main fuel supply line, the Kero Fadec will work OK and save me lots of ££££'s.

Gordon

Edited By Gordon Whitehead 1 on 15/10/2015 16:09:04

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Thanks, Gordon. The rudder bar I've made is very similar to yours (couldn't be much different, I suppose). The main difference is that mine still has some PC tracks still visible but they'll be hidden once it's all finished.

I'm going to fit snake outers to feed the elevator closed loop wires back to the (single) elevator servo. I think it will work OK, particularly if I keep them as straight as possible. I had thought about using a servo for each elevator half but it seems to be overkill on a smallish model. With care it will be possible to get the elevators moving equally and in synchronism.

Geoff

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