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Scram

Convert AMT to tail plane/elevator

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Scram

I don't like all moving tails and would like to convert my Typhoon tail to a fixed tail plane with elevator.

Has anyone done this?  Like to share the method?

If so, it's clearly important to get the incidence of the fixed plane correct, but what should the incidence be with relation to the wing?

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isoaritfirst

Fly it Jerry and set the incidence you want on the trim. 

Then mark it, before cutting the elevator into the tailplane. 

But how big to make the elevator. That’s a question that may need some research

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satinet

'Why' is a pretty big question. Loads of work for no or minimal improvement on a model that has good pitch stability and good elevator response. 

 

As memory serves the two tail planes have a v notch out the back to allow for rudder deflection. 

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stewartg

I went the other way, just to see.... and converted one of my Arestis from elevator to AMT.

Minimal difference except the AMT needed much more movement for the same response, something I can’t quite figure.

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wookman

AMT will need more movement because you are not "cambering" the section when you apply the elevator command. 

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SilentPilot

I might try an AMT with an elevator on the back, linked up to give very subtle movements to complement the control.

It could be the best of both worlds...
or the worst!

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Phil.Taylor
On 16/02/2019 at 18:10, Scram said:

I don't like all moving tails and would like to convert my Typhoon tail to a fixed tail plane with elevator.

Jerry - just what is it you don't like about AMTs?

Is it the tosh & nonsense peddled by the "Schwing" "Aresti" crew?

The easy rig ? flat pack? not having to worry about "incidence issues"?

My 2p - if you really want a fixed X  tail / elevator - buy a plane like that - but there are precious few that rig & pack easily.

Don't let me stop you though - hacking stuff is all part of the fun

Phil.

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Phil.Taylor
7 hours ago, stewartg said:

I went the other way, just to see.... and converted one of my Arestis from elevator to AMT.

Minimal difference except the AMT needed much more movement for the same response, something I can’t quite figure.

Angular movement - degrees?

Or linear movement - mm?

30 degrees on an AMT is pretty dramatic - 30 degrees on an elevator less so.

Either way can achieve the same thing - good control response up to the point where it's too much & the tail stalls & hey presto  - a flick/spin. 

Phil.

In spin recovery mode...

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Scram

Thanks for the responses everyone.  To answer a few questions:

No, I'm not responding to any tosh n nonsense -  I haven't seen it.  I take the point that the fixed tail makes packing and carrying more difficult.

My reason for considering it is the floppy nature of the AMT, it seems so crude and I worry at its possibly falling off in flight, though I have never experienced a problem.

I like cross tails like my Wizard and former Aresti.  Does not the Aresti have a removable tailplane?

The cause of the question really is one of how to convert to the actuation of an elevator rather than AMT, with minimum/no chopping of the fuselage.

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Phil.Taylor

Floppinesss - if that's a sloppy fit of joiner into bearing (been there) a couple of winds of Diamond tape on the centre of the joiner will sort it. If it's sloppy fit of tails onto joiner- use a bit of prit-stick on the joiner - it's just sticky enough to hold the tails on. If it's a steel joiner - bend a kink into the end of the joiner for a bit of grip.

The mod to elevator - yes it will be some serious fus rear end hacking to do it right. Interesting & fiddly work. Study the arrangement of the Needle 100 tail - Schwing too. Good luck & draw it all out on paper before hacking anything.

Phil.

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satinet

You'd probably have to cut a hole a in the fuse. Bear in mind the tail doesn't sit behind (or in front of) the rudder so a simple pushrod that exits out the back won't work. Look at the tail on a modern f3j or f5j model. They have moved away from AMT but the tail design is quite different - i.e the tail is in front of the fin and bellow it. The typhoon has a true x layout with the tail mid fin.

The only way i can see it working on that model is to install a longer bell crank that activates the two elevator halves, which you need to cut in the tails, via a pin. But you would probably run in to problems with the rudder getting in the way. And it could still fall off.

The stormbird tail is still a two half thing that's held on by friction AFAIK

I've never had a problem with the tail coming off on my tragi and I've flown it in f3b and f3f a fair bit. Plus a little ds and f3j - never mind slope. The tail never fell off my typhoon either (or any other amt I've had).

I don't see what's crude about a crank operated tail plane to be honest. 

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Woodstock

Don't do it Jerry.

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isoaritfirst
2 hours ago, Woodstock said:

Don't do it Jerry.

I agree.  Not worth the aggro

 

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Scram

mmmmm . . . . . . . . . .   you are likely quite right  :thumbsup:

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