Do you tweak your control syrfaces when you build planes?

[FishInferno]

I didn't really know how to word the title, but that sounds good enough.

Anyway, until recently, when I built planes I just let all of the control surfaces perform all tasks. I only recently started making it so that the elevators only controlled pitch, the ailerons only control roll, and the rudder only controls yaw. So what do you do? Do you assign control surfaces to specific tasks or let them all do all the work?

[cantab]

Of course. I know what controls I want doing what job. FAR gives me more subtle options to control how much they deflect by too.

And pod torque and engine gimbal go off for a regular plane, the control surfaces alone should handle it. But I'll use the magic of reaction wheels to make unorthodox things fly straight.

[qromodynmc]

Definelitely, if you dont assign tasks to them, for example while turning and rolling, it'll perform worse. If you try to roll, it'll lose some pitch control, if you try to pitch, it'll lose some roll capability.

[FishInferno]

Definelitely, if you dont assign tasks to them, for example while turning and rolling, it'll perform worse. If you try to roll, it'll lose some pitch control, if you try to pitch, it'll lose some roll capability.

Actually this isn't true. If you have Elevons and roll and pitch at the same time, you will notice that one side will "roll" less to help with the pitch

[_stilgar_]

I only turn off control functions on airbrakes. The rest does everything on auto.

[Superfluous J]

I do it, because everybody says I should. I even have pretty vague hand-wavey notions of how and why it helps.

[Kuu Lightwing]

I do because I like my control surfaces to do what they should do. I.E. Elevator for pitch control, Ailerons for roll and rudder for yaw. When, say, canards try to roll my plane, it just feels wrong.

[Renegrade]

Of course. I know what controls I want doing what job. FAR gives me more subtle options to control how much they deflect by too.

FAR's tweakable is a perfect example of how it should be done. It's extremely powerful and yet not much larger (UI wise) than the very, very barebones stock mechanism.

Actually this isn't true. If you have Elevons and roll and pitch at the same time, you will notice that one side will "roll" less to help with the pitch

Having control surfaces bound to multiple control inputs isn't a binary good/bad situation. Sometimes having other surfaces pitch in can help, but at other times, it can harm in different ways. For (the most simple) example, you can end up with too much control authority (especially in roll with narrow craft), resulting in twitchy controls and flappy SAS. Another issue that can crop up is that you can be adding too much drag by having control surfaces with bad authority pitching in. Other issues include strange interactions resulting in a skid, or such.

In short, intelligent assignment of surfaces will always beat the pants off of the 'all helping' model.

FAR's widget for controlling the surfaces is even better: you can have a surface react negatively to an input. In some of my (oldFAR) designs, adding a little bit of negative roll to the rudder can help prevent some serious shenanigans.

[nalfz]

Kind of have to because half of them still pitch the wrong way under bizarre circumstances

on the other hand things'll fly a lot better with control surfaces dedicated to one thing

[User Unrelated]

I generally only take the yaw ability away from things that aren't vertically mounted. I tend to design planes with gull-wings, or wings angled slightly horizontally... and having all those control surfaces try and create a yaw effect usually results in disaster.

[MalfunctionM1Ke]

Sometimes i rotate them a little so they are not flat in the airlow but constantly add a little more lift.

So yeah, it is important to keep an eye on what your controlsurfaces are doing.

[Feradose]

I set canards to lower deflection and make the rudders control yaw only.

[mythic_fci]

I tend to allow horizontal control surfaces to do whatever they want; I just disable Yaw on them so they don't try to yaw me into oblivion. For completely vertical tails, I disable everything but Yaw; for V-tails, I allow them to act as either just Pitch and Yaw or all 3.

[problemecium]

Meh. I tried it out for a while when the option was first added, but I've found that it doesn't do much to save a bad plane design, and on a good one they'll do what they're supposed to without needing any modifications.

[Wjolcz]

I assign different functions to control surfaces ever since it was introduced. The old system where you couldn't do anything about that was horrible.

[Red Iron Crown]

I assign them specific control axes every time. I usually have placed them so that they have good leverage in only one axis, so it makes sense to do so.

[Captain H@dock]

I even change mine during flight. Ie: I enable pitch on the outboard Elevons at the trailing edge of a delta wing for greater low speed pitch authority during final and the flare.

[Mister Dilsby]

Always, and with horizontal surfaces I also add their "Deploy" action to the Brakes group.

[GoSlash27]

I not only assign tasks to different control surfaces, I don't use an active rudder and I keep active control surfaces to the bare minimum. Many of my smaller designs have no active control surfaces whatsoever.

Best,

-Slashy

[ShawnPhillips]

I work on real aircraft for a living (though I am getting out of the air force soon.) so I understand what control surfaces should do what for best results. Plus real planes can break if they over-G so some control surfaces are limited and I like to make my planes perform somewhat realistically.

[Mikki]

Yes, larger planes mandatory. Rolling at the wingtips helps alot...

[Hagen von Tronje]

I've gotten interesting experimental results.

I have a nice, midweight (10t) prop-driven STOL that's been very nicely tuned in construction. It's by far my favorite flyer. It sports two tailfins, carefully aligned. With all control surfaces enabled, it takes off at 42m/s. With airbrakes disabled as a control surface but all others enabled, it takes off at 39.5m/s. With tailfins on yaw only, it doesn't take off until 48.5m/s. Presumably the fairly large tailfins are able to pitch into that much extra lift on takeoff.

I find this trait is preferable enough for my purposes to be worth more than the cost in drag or high speed handling - its top speed is under 300m/s even at altitude. Makes for an exceptional bushplane.

Edited September 2, 2015 by Hagen von Tronje

[Red Dwarf]

I have too. The Swordfish in my sig is unflyable unless you disable some control surfaces.

[RoboRay]

Roll-rates tend to be excessive (too twitchy) if I don't limit the number of control surfaces that apply roll.

[GDJ]

I set them just like a real airplane. Works great.