Elevons or Rudder only with polyhedral? - RC Groups
Thread Tools
Oct 09, 2017, 03:00 AM
Registered User
ninjasword71's Avatar
Discussion

Elevons or Rudder only with polyhedral?


Been searching but some say yes, others no. Some say would work only on outboard part of wings. I think I have 20 all together. Or ailerons on outboard and elevator on inboard part. I wanted a rudder only rig but too much thought causes the mind to wonder. I love elevons but concerned about the turns. Would they work on this design?
Sign up now
to remove ads between posts
Oct 09, 2017, 05:50 AM
Registered User
flypaper 2's Avatar
Likely would not work well, if at all.
Rudders close to the CG don't work well with not enough leverage, like a full length fuse. would have.
I have a Fokker DR1 with no dihedral that works well with rudder. It does have ails as we..
I'd stick with the ails.

Gord.
Oct 09, 2017, 06:46 AM
Registered User
Extreme Sports's Avatar
I'd put my money on elevons being the better option. That is not much polyhedral and there is very little moment arm for the rudders to work with. Quite possible those rudders would actually roll the plane the WRONG way (there was thread a few months back that discussed this happening on an F22)
Oct 09, 2017, 12:58 PM
Registered User
ninjasword71's Avatar
Elevons on outside or inner panel?
Oct 09, 2017, 02:09 PM
Registered User
flypaper 2's Avatar
To keep it mild mannered, put the ails on the outside and the elev on the inside. For more aerobatic capability make the whole trailing edge elevons.
If you havn't flown the plane yet, or very little, I'd just go with the regular ails and elev.

Gord.
Oct 09, 2017, 08:55 PM
treefinder
springer's Avatar
some time ago (like 12 years) I built gpw's stealth delta from OC pink foam scrounged from a dumpster and as I only had a non computer radio, made ailerons outboard and elevator in center section behind the motor. It flew, but not well. I finally popped for a mixer and separated the elevator halves and glued them to the ailerons and made them into elevons. That flew a treat! Still have it. two V stabs no rudders - Plenty of maneuverability.
Oct 09, 2017, 09:06 PM
Registered User
ninjasword71's Avatar
Springer, elevons outboard or mixed with some inboard at the bend?
Oct 09, 2017, 09:09 PM
Registered User
ninjasword71's Avatar
Sorry, I was wondering with polyhedral if just elevons would work and which position on wing
Oct 09, 2017, 10:16 PM
treefinder
springer's Avatar
Yes, elevons only will work fine. You will have to tune your throws, of course, but that's one of the fun aspects of scratchbuilding. I would go with outboard only first. If you set the servos toward the inboard portion of each elevon, you could add control wires to horns on the inside surfaces and work both from a single servo, (perhaps, depending on the actual geometry) or, add two more servos to add in the inboard surfaces. But I wouldn't be surprised that you find flight characteristics to be ok with just outboard. With the dihedral, you will get some turning with ailerons, so the elevator function may not be as critical. If you want to do tight loops, though, You may have to add throw to the elevator function. You just have to build it and play with it.
Oct 09, 2017, 10:46 PM
Registered User
ninjasword71's Avatar
What if the elevons were mostly inboard with a couple inches on the outboard area? The servo wires only go so far and don't feel like adding extensions
Oct 10, 2017, 02:59 PM
treefinder
springer's Avatar
I did inboard ailerons on a 2 meter glider for the same reason and while it is "ok" for a motor glider, one of the things on my to do list is add two servos and ailerons to the poly tips and use the inboard ones as flaps/spoilers.

Depending on how far out board you can get the servos, you may be able to set the control rods at an angle like you would if you used a single servo in fuse for ailerons. Not the most aerodynamic, but works.
Oct 10, 2017, 07:15 PM
Registered User
ninjasword71's Avatar
Ended up with inboard elevons. Was pretty twitchy as I can't do expo on gear channel using a dx6i.
Oct 10, 2017, 07:57 PM
treefinder
springer's Avatar
Well, there ya go, potential aileron sluggishness solved!
It might just be a good training exercise.
Oct 10, 2017, 08:50 PM
Registered User
ninjasword71's Avatar
Bucking bronco
Scratch Built Easy Floater RC Plane Maiden (0 min 50 sec)
Oct 11, 2017, 03:40 AM
flyin' fool
goldguy's Avatar
Tail heavy!! And what makes it worse is you have too much elevator input. would have put the elevens outboard.

Elevons on a DX6i....................didn't your select 'elevon' in the 'wingtailmix' program? Try that and then fiddle with servo reverse and plug assignment until you get the proper directions. Do a google or check youtube to see how.
Last edited by goldguy; Oct 11, 2017 at 04:04 AM.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question How to mix throttle with elevons on DX8 Rogrc Flying Wings 4 Jun 29, 2016 10:16 AM
Help! Help with ailerons on a polyhedral wing and adverse yaw. no rudder. nicolelc Foamies (Scratchbuilt) 13 Feb 27, 2016 12:46 PM
Question Can you do point rolls on elevon plane if you add a rudder? romans1015 Electric Plane Talk 8 Jun 02, 2008 04:05 PM
Discussion Can you do point rolls on elevon plane if you add a rudder? romans1015 Slope 5 May 30, 2008 05:37 PM
Polyhedral with ailerons/no rudder, - OK? Discharger Electric Sailplanes 11 Oct 31, 2004 06:33 PM