HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 23, 2012, 07:31 PM
person
derp express's Avatar
Joined Dec 2012
160 Posts
Question
Eliminating channel mixing

Gents,

I know this probably sounds like a step backward technologically, but would it be feasible to eliminate or mitigate potential pitch sensitivity in a nurflugel or other flying wing type of aircraft by having the elevator and aileron controls on separate, unmixed channels, where the ailerons are still large surfaces with long throws for quick rolling, but the elevator(s) are just tiny surfaces with short throws enough to give the wing smooth pitch control, but not enough to throw it into a tumble with too much control input? I'll admit I have little experience with wings, but this idea occurred to me as something that might theoretically work.
derp express is offline Find More Posts by derp express
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 23, 2012, 09:59 PM
internet gadfly
nmasters's Avatar
Colorado
Joined Aug 2006
2,145 Posts
It's not unusual at all for planks to have an elevator in the middle with ailerons outboard. Swept wings can also be configured that way but for smaller sweep angles elevons produce better pitch response.
nmasters is offline Find More Posts by nmasters
Reply With Quote
Old Dec 25, 2012, 09:49 AM
Registered User
1967250s's Avatar
United States, VA, Alexandria
Joined Sep 2008
985 Posts
What about a mechanical mixer? A double swing arm, like the o es used for v tails? Then you'd have best of both worldsnand andnot have to have a fancy mixing radio
1967250s is offline Find More Posts by 1967250s
Reply With Quote
Old Dec 25, 2012, 11:29 AM
Just call me crash for short
Quick61's Avatar
United States, OH, The Plains
Joined Jan 2011
1,673 Posts
Quote:
Originally Posted by 1967250s View Post
What about a mechanical mixer? A double swing arm, like the o es used for v tails? Then you'd have best of both worldsnand andnot have to have a fancy mixing radio
As far as mechanical mixing goes, there area couple of good examples with the Eclipse (V-tail) that slides the servo tray for elevator movement and the Voodoo that has mechanical mixing for elevon. I think the Voodoo is a good example to follow for mechanical mixing on flying wings.

Mark
Quick61 is online now Find More Posts by Quick61
Reply With Quote
Old Dec 25, 2012, 11:32 AM
Herk
HerkS's Avatar
Virginia USA
Joined Jun 2007
1,577 Posts
The radio systems I use allow elevon mixing control, such that I can easily adjust the amount of elevator movement that I want - relative to the amount of aileron movenemt that has been set. Separate surfaces can be used but that means I would need to use more servos. I have both plank and swept flying wing models that use elevons. I almost always want to modify the elevator and aileron movement separately.

Mechanical mixers can do this with somewhat more complexity - though the newer programmable radio systems essentially remove the need for them. They also allow quick on the field changes during a flying session.
HerkS is online now Find More Posts by HerkS
Reply With Quote
Old Dec 27, 2012, 03:27 AM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,341 Posts
These days, if you don't have a computer radio and want to fly a wing or delta, I would suggest getting a V-tail mixer and use it to get elevon mixing. They are cheap these days:

http://www.hobbyking.com/hobbyking/s...tra_small.html
http://www.hobbyking.com/hobbyking/s...ail_Mixer.html
http://www.hobbyking.com/hobbyking/s...200_step_.html

Much less hassle than mechanical mixing.

However, you may just be curious about the feasibility of separating elevator and ailerons on wings. Well, it's been known to work for planks, swept forward wings and deltas. Usually with the elevator set up in the center and ailerons on wing tips. I've built an experimental delta myself with this setup and it works great.

For swept-back wings, both elevator and ailerons want to be at the wing tips. Ailerons wants to be outboard for leverage and elevators wants to be rearward for the same reason. And for a swept-back wing both occupy generally the same space. If I were to try this I'd put the elevators on the wing tips with slightly inboard ailerons. That way, applying up elevator would get me automatic yaw stabilization.
slebetman is offline Find More Posts by slebetman
Reply With Quote
Old Jan 07, 2013, 12:28 PM
Registered User
United States, CA, Simi Valley
Joined May 2011
14 Posts
This is kind of moot with today's computer radios and cheap mixers, but I always wondered why you couldn't just physically rotate the gimbal in your transmitter 45 degrees. Does anyone know if that was done back in the old days? I did the math and it would work as a crude v-tail or elevon mix. Just curious.
jeff93063 is offline Find More Posts by jeff93063
Reply With Quote
Old Jan 07, 2013, 02:44 PM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,341 Posts
Quote:
Originally Posted by jeff93063 View Post
This is kind of moot with today's computer radios and cheap mixers, but I always wondered why you couldn't just physically rotate the gimbal in your transmitter 45 degrees. Does anyone know if that was done back in the old days? I did the math and it would work as a crude v-tail or elevon mix. Just curious.
I actually flew once like that. Before I got my computer radio*. And that was just three years ago. Works but got weird stares from others at the field. Also crashed all the time but that could be because I was a newbie then.


*note: actually, I'm still using the same HK-T4A radio, only heavily modified and wrote my own software so I could have a computer radio.
slebetman is offline Find More Posts by slebetman
Reply With Quote
Old Jan 07, 2013, 06:12 PM
Needs brain lubrication
biber's Avatar
Aachen, very western Germany
Joined Dec 2004
1,391 Posts
You can have separate controls without any mixing in a plank, as already suggested by Norm.
You can aswell have it in a swept wing, using a setup like the Multibumm.
http://www.rcgroups.com/forums/showthread.php?t=504495

biber
biber is offline Find More Posts by biber
Reply With Quote
Old Jan 07, 2013, 07:28 PM
Registered User
slebetman's Avatar
Malaysia, Selangor, Kajang
Joined Jun 2009
1,341 Posts
One type of control that I've always thought to be natural for flying wings is the kind employed by the Dunne series of flying wing biplanes. It didn't have elevon mixing instead used two control sticks, one on either side of the pilot, to directly control each elevon. The pilot is the elevon mixer.

To do this with RC equipment I guess you'd need to modify your TX and install a spring on the throttle stick. Then employ some other input for throttle control (one of the knobs on your TX?). For a glider, you don't need throttle. And some of my planes I fly on full throttle 100% of the time, those planes could probably be configured with one of the switches as throttle.
slebetman is offline Find More Posts by slebetman
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Building a Flying wing & channel mixing derp express Flying Wings 6 Dec 25, 2012 01:15 AM
Discussion Phoenix Futaba channel mixing twalther Simulators 0 Nov 03, 2012 10:23 AM
Discussion Gyro's on mixed channels NX-687 Radios 0 Jul 09, 2012 09:01 PM
Discussion Control, channels, mixing and servo query - absolute beginner! Asatorae Beginner Training Area (Aircraft-Electric) 15 Jul 07, 2012 06:22 AM
Discussion Removing mixing AND mixing only 2 channels-Esky 6ch radio Stamp Radios 7 Oct 25, 2010 07:36 AM