control throw for FULL FLYING STAB?
02-17-2011, 08:06 AM
#1
Thread Starter
control throw for FULL FLYING STAB?
Hello-
This may seem like an odd request, but I'm trying to set up an EDF jet with a full-flying stab and I need a general idea where to start with the control throw. I've heard that a lot of sailplanes have full-flying stabs, so I thought I'd try to get some input in this forum.
I've never had a model with a full-flying stab before, so I don't know if they generally need more control throw than a conventional stabilizer/elevator tail, or less?
Another sailplane pilot kindly replied to this post in another forum and said he thought that the travel should be pretty much the same (as measured at trailing edge) as a regular fixed stab with moveable elevator. He cautioned, though, that he wasn't 100% sure.
The airframe's a Starmax 60mm F-14 with a 44" wingspan (when wings are fully open).
Thanks in advance for any info you can provide-
This may seem like an odd request, but I'm trying to set up an EDF jet with a full-flying stab and I need a general idea where to start with the control throw. I've heard that a lot of sailplanes have full-flying stabs, so I thought I'd try to get some input in this forum.
I've never had a model with a full-flying stab before, so I don't know if they generally need more control throw than a conventional stabilizer/elevator tail, or less?
Another sailplane pilot kindly replied to this post in another forum and said he thought that the travel should be pretty much the same (as measured at trailing edge) as a regular fixed stab with moveable elevator. He cautioned, though, that he wasn't 100% sure.
The airframe's a Starmax 60mm F-14 with a 44" wingspan (when wings are fully open).
Thanks in advance for any info you can provide-
02-17-2011, 08:54 AM
#2
RE: control throw for FULL FLYING STAB?
full flying stab needs VERY little movement...
when 100 percent of the surface moves it is much more effective, and efficient. Especially at high speeds
You could probably setup the radio with some exponential so that it is slow around center, and gives you more throw out further if you would need or want it.
I keep thinking of other things to add ! Also since you have no prop wash on a ducted power system you won't get any prop wash over them at low speed ...
So I am slowly talking my confidence down
when 100 percent of the surface moves it is much more effective, and efficient. Especially at high speeds
You could probably setup the radio with some exponential so that it is slow around center, and gives you more throw out further if you would need or want it.
I keep thinking of other things to add ! Also since you have no prop wash on a ducted power system you won't get any prop wash over them at low speed ...
So I am slowly talking my confidence down
02-17-2011, 12:05 PM
#3
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RE: control throw for FULL FLYING STAB?
The guy that suggested that is spot on as pertains to normal layouts. But with the distance from the wing to the stabilator being as short as it is you may need a bit more authourity to flare nicely for landings or for use at slow speeds. If you have dual rate switches on your Tx I'd suggest setting up the low rate just as your buddy suggested and the high rate with about one and a half times as much throw. Do the initial flying with the low rate and see if it performs well with trial "landings" done at high altitude before making your first approach.
The reason it'll seem like so little just as foodstick suggests is because when the whole stabilator moves the trailing edge as much as a regular elevator the actual angular change of the whole surface is a very small amount and it LOOKS like it's hardly moving. But in truth the shift in angle of attack for the full flying and conventional elevator for full throw inputs is the same.
Best of luck with the first flights on that great looking model.
The reason it'll seem like so little just as foodstick suggests is because when the whole stabilator moves the trailing edge as much as a regular elevator the actual angular change of the whole surface is a very small amount and it LOOKS like it's hardly moving. But in truth the shift in angle of attack for the full flying and conventional elevator for full throw inputs is the same.
Best of luck with the first flights on that great looking model.
