Swept tail elevator design?

[Charlbarl]

Hey everyone!
Hope you've been staying safe and healthy.
I've been designing a new foamie with swept wing and tail and am stuck on how to implement elevators with the swept tail. I can't really find any example and want to tie elevators to one servo...
Any single elevator setup tends to bend the entire tail due to the angle at the center of the tail...
Any help or examples would be greatly appreciated!

 

[OliverW]

Hey everyone!
Hope you've been staying safe and healthy.
I've been designing a new foamie with swept wing and tail and am stuck on how to implement elevators with the swept tail. I can't really find any example and want to tie elevators to one servo...
Any single elevator setup tends to bend the entire tail due to the angle at the center of the tail...
Any help or examples would be greatly appreciated!
View attachment 167158

You'll be fine. Your plane should be super floaty

 

[Charlbarl]

You'll be fine. Your plane should be super floaty

So you think just let the tail bend?

 

[Keno]

If I recall correctly on a Mig 15 what it had was two pushrods, attached to the same servo arm. you could probably do the same by splitting the pushrod down to "V" out to each elevator. Just make sure in elevator movement they don't touch.

 

[Charlbarl]

If I recall correctly on a Mig 15 what it had was two pushrods, attached to the same servo arm. you could probably do the same by splitting the pushrod down to "V" out to each elevator. Just make sure in elevator movement they don't touch.

Oh I like that idea! I guess I should place the servo slightly off center so that the neutral point of the arm is in the center. I'll go for this, thanks friend!

 

[Merv]

All good ideas, why not just make the hinge line straight.

 

[Charlbarl]

All good ideas, why not just make the hinge line straight.

Lmao interesting... This thought slipped by me after attaching the tail I already made but good point. I could cut down on drag a bit this way too. Thank you!!!

 

[Monte.C]

Hey everyone!
Any help or examples would be greatly appreciated!

That's so weird - I just wrapped up the SAME exact question on this thread I started I think yesterday:
https://forum.flitetest.com/index.php?threads/is-there-any-better-elevator-control.63026/

 

[OliverW]

So you think just let the tail bend?

Sorry. I was barely awake, and I only really read it as a swept tail lol. I would do a V pushrod setup or use another servo

 

[Merv]

That's so weird - I just wrapped up the SAME exact question on this thread I started I think yesterday:
https://forum.flitetest.com/index.php?threads/is-there-any-better-elevator-control.63026/

Maybe I’m not seeing it but I thought you asked about a dihedral tail, not a sweep tail

 

[Monte.C]

Maybe I’m not seeing it but I thought you asked about a dihedral tail, not a sweep tail

The issue is exactly the same either way: when the two control surfaces don't share the same hinge axis.
They can be angled up (dihedral), down (anhedral) or swept back.

 

[quorneng]

I had the same problem on my sub 250 g EDF Canberra. Not swept but the tail has significant dihedral and I could not afford the weight of two servo so it uses a V push rod

This was before the fin was added so one push rod actually has to pass thought the fin.

 

[Merv]

The issue is exactly the same either way: when the two control surfaces don't share the same hinge axis.
They can be angled up (dihedral), down (anhedral) or swept back.

With a swept tail, is possible to make the hinge line share the same axis, the elevators will be triangular. Just make the hinge line straight, no need to make the hinge parallel with the TE. I agree this is not possible with dihedral tail.

 

[Monte.C]

With a swept tail, is possible to make the hinge line share the same axis, the elevators will be triangular. Just make the hinge line straight, no need to make the hinge parallel with the TE. I agree this is not possible with dihedral tail.

Exactly. I didn't say the problem is with a swept tail - few of our tailplanes are rectangular. We're talking about the alignment of the hinge axes, not the shape of the surfaces. We're in agreement.