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Ailerons, flaps, spoilers, etc. - 4/5/2008 11:15:05 PM   
gaRCfield


 

Posts: 1274
Joined: 5/20/2008
From: Burlington, VT, USA
Status: offline 		Hey there,
I'm a beginner - have a Nexstar, will be flying for first time the first weekend in May. I just am a little curious about some stuff:

I was recently on an airplane traveling to Colorado, and conveniently chose a window seat just behind the wing. I noticed that the ailerons are only at the very end of the wing, and I did not see them move down once, only up. The flaps are very close to the fuselage of the plane, and push way down and back for landing, and are pushed half-way down for take off. There are also what I imagine are spoilers along the top length of the wing, which operated up only for very heavy banks and for slowing down after landing.

Are there model planes that are set up to operate similarly? I am very interested in scale-like operation of model planes, as opposed to crazy aerobatics. I know that the Nexstar is capable of flying with ailerons and flaps, and I'm wondering if, when I get good at flying, I can simulate what I saw on the full-size plane I was flying on, maybe having ailerons at the tips of the wings, and flaps near the fuselage that will act as spoilers during flight or something.

Thanks.

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 12:04:54 AM   
seanreit



Posts: 6766
Joined: 4/17/2002
From: Cedar Park, TX, USA
Status: offline 		All is possible with time and money

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 12:21:27 AM   
mikekosatka


 

Posts: 187
Joined: 6/26/2004
From: houston, TX, USA
Status: offline 		The short answer is... Yes and No. Of course you can duplicate any thing you see but, the problem withless than full scale models is that they fly through an ocean of full sized air molecules.That is to say that smaller control surfaces react to air differently than do full size. Also the other dynamics of aircraft don't necessarily scale down. A 1/4 scale P-51 mustang will not weigh 1/4 of what the real one does. We modellers get away with a lot of things full size can't, but it works both ways. Keep reading this forum about the different surfaces and how they react ( or don't react). Most of it is over my head ( pun intended) but makes interesting reading, and dont be afraid to ask "stupid or hypothetical questions, some of these guys love them. Read the airplane on a treadmill thread, for instance. Something that can be "real world " tested in minutes is debated for weeks!!!
Mike

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 12:54:22 AM   
gaRCfield


 

Posts: 1274
Joined: 5/20/2008
From: Burlington, VT, USA
Status: offline 		seanright-
what the heck is that thing? can you fly me to cali???

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 1:30:42 AM   
da Rock



Posts: 6705
Joined: 10/11/2005
From: western, NC, USA
Status: offline 		There really are a number of things you saw that are carryovers into modeling.

Individual things work for us in certain situations and are worthwhile to do. For example, you watched differential ailerons in action on that airliner. Some of our models benefit greatly from those. A buddy of mine and I will be maidening his new Monocoupe as soon as weather permits. It's a highwing tail dragger. This one is no.2 in our series. Number 1 had a bad case of adverse yaw. When we wanted to roll into a turn with ailerons the sucker would roll but it'd yaw the wrong way with the roll. Roll left, it'd yaw right. Roll right, it'd yaw left. My buddy is challenged with a number of things. So we trim and rig controls to so the surfaces fly true. That is to say, ailerons just make the airplane roll, rudder only causes yaw, etc.

So with Monocoupe 1, we rigged the ailerons to move about 3x up to 1x the deflection down. That way instead of adversely yawing with ailreon movement, the sucker just slightly yaws into the turn. What you saw on the airline isn't to fix a problem however. It's so the airplane flies more efficiently. Those airliners very seldom have problems that need fixing. But every little bit of fuel savings counts. And they like the way the upgoing aileron helps turn the airplane into the turn. So their ailerons move up a lot, and down almost not at all. And the wing going down also tends to lose a bit of speed at the same time.

Differential ailerons are easy to do just adjusting your servo arms. And we could do that on every model we have, but we don't need it on the majority. And we really do NOT want it on most. But that's a carryover that does help sometimes.

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 1:55:04 AM   
gaRCfield


 

Posts: 1274
Joined: 5/20/2008
From: Burlington, VT, USA
Status: offline 		Hmm, thanks.

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 2:32:45 AM   
crasherboy


 

Posts: 112
Joined: 10/21/2006
From: Bryant Pond, ME, USA
Status: offline 		The flaps you mentioned as going way[and back] down on landing and only down part way on takeoff is pretty much the same as done in a Cessna light plane. On a small Cessna the flaps move back some as they go down,they are also VERY effective to. Also you can not deploy them at cruising speed ,if you did you could do some real damage. In a Cessna 152 you must be under 90 mph or so before you lower them. But when you go all the way down ,it is putting on the brakes. Typical takeoff is only abour 15 degrees down so as to not put up to much resistance for takeoff. But in a soft field situation ,all the way down,reason being you want to get off the ground as quick as possible . For the most part modelers do not go to the work of building flaps that as they do in a Cessna,but there is no reason that you couldn't,in fact if you did you could get in some real SLOW landings! IMHO ,if one were to build and airliner model ,say in the 30 foot wingspan or so ,I think there is no reason you could not build it close to the way the full scale is built,and I think it would respond a lot like the full scale to. Of course ,there is always the scale effect. I have had the desire to build a model of a B29 in about that wingspan would that not be a project?!

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RE: Ailerons, flaps, spoilers, etc. - 4/6/2008 2:40:56 AM   
gaRCfield


 

Posts: 1274
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quote:

ORIGINAL: crasherboy

IMHO ,if one were to build and airliner model ,say in the 30 foot wingspan or so ,I think there is no reason you could not build it close to the way the full scale is built,and I think it would respond a lot like the full scale to. Of course ,there is always the scale effect. I have had the desire to build a model of a B29 in about that wingspan would that not be a project?!


If you build that thing I'll drive to Maine to see it =)

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RE: Ailerons, flaps, spoilers, etc. - 4/8/2008 12:59:10 AM   
TRCX


 

Posts: 185
Joined: 7/15/2004
From: capetownwestern cape, SOUTH AFRICA
Status: offline 		the flaps on the big commercial jets are known as fowler flaps. they slide backwards before hinging downwards, thereby increasing both camber and chord, creating a larger wing surface better tuned for lower speeds. \

there are a few different type of flaps
Krueger flap - hinged flap on the leading edge.Often called a "droop."
Plain flap — rotates on a simple hinge. like the ones we use on most models...
Split flap — upper and lower surfaces are separate, the lower surface operates like a plain flap, but the upper surface stays immobile or moves only slightly.
Fowler flap — slides backwards before hinging downwards, thereby increasing both camber and chord, creating a larger wing surface better tuned for lower speeds.
Fairey-Youngman flap - moves bodily down before moving aft and rotating.
Slotted flap — a slot (or gap) between the flap and the wing enables high pressure air from below the wing to re-energize the boundary layer over the flap. This helps the airflow to stay attached to the flap, delaying the stall.
Blown flaps — systems that blow engine air over the upper surface of the flap at certain angles to improve lift characteristics.

ive got a Funtana s40 and i have flaps mixed in on the alerons. the can be adjusted to different degrees of travel form 0 degrees to 50 degrees, while the flaps are down the radio mixes in the aleron imputs so the alerons can still function while holding the flap possition, when the flaps are lowered the plane pitces down slightley but also slows down dramatically and can be flown at walking speed without wingrock or stalling. i can also reverse the function on the radio to provide spoilerons which use the same method of mixing and act as a massive airbrake it is sometimes used on 3D manuvers..(picture 1/3 of the wing at 45 degrees upward deflection, thats a massive airbrake!!!)

if your nexstar has a servo per aleron you could accomplish the same kind of mixing so you could either get flaps or spoilers. but remember the nexstar is a trainer and is designed with a light wing loading and it usually aproblem for most beginers get the plane down because they just float forever so adding flaps will only increase the lift and delay the stall but that plane will probably float on forever. if you slow it down in a good wind itll look like the plane is flying backwards lol

gud luck with that first flight!!!
im also just into the flying stuff... 25 hours so far but ima quick learner hence the Funtana s40.
and remember to have fun!!!

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Funtana S 40: ASP .52 series 3 Pitts muffler JR XP6102 JR R770S SPCM JR ES-539(rudder,elevator) JR Nes-537(ailerons,throttle

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RE: Ailerons, flaps, spoilers, etc. - 4/8/2008 3:23:49 AM   
gaRCfield


 

Posts: 1274
Joined: 5/20/2008
From: Burlington, VT, USA
Status: offline 		thanks.

If you took the droops and speed brakes off the Nexstar, and took the dihedral out of the wings, would the plane fly faster, and then maybe have a use for flaps?

< Message edited by FatOrangeKat -- 4/8/2008 4:05:44 AM >

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RE: Ailerons, flaps, spoilers, etc. - 4/8/2008 11:28:23 AM   
da Rock



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From: western, NC, USA
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quote:

ORIGINAL: FatOrangeKat

thanks.

If you took the droops and speed brakes off the Nexstar, and took the dihedral out of the wings, would the plane fly faster, and then maybe have a use for flaps?



Dihedral has little effect on speed.
Speed brakes have significant effect on speed.
Droops probably have an effect on speed. Their presence gives the wing two different airfoils on one wing. The two won't have the same lift slope nor the same drag slope. So one or the other is going to be less efficient. Drag half the wing around producing less efficiency and you've got guaranteed excess drag. How much? Who knows.

When you clean up an airframe, remove all the excess drag you can remove, it will fly faster. It will still fly as slowly as before. It can even fly more slowly, but we usually don't notice. Most modelers can't identify a difference of 10-15mph, much less 5 or so. So not many actually notice. And few modelers would try for slower speeds on an airplane they just made faster. With the removal of those droops, it's probable that whatever speed it's flying, it will do so at a significantly different AOA. It might even be enough difference the average modeler would notice. The AOA range would probably lessen, so the ability to judge speed would be required even more. etc etc

Very few of our models need flaps. So they wouldn't "have a use for them" other than for fun.

The plane flying faster top speed has little to do with needing flaps. And cleaning up the airplane won't significantly change how slow the airplane can fly. So flaps aren't going to be required more one way or the other.

If you want to have them, plug 'em in.

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RE: Ailerons, flaps, spoilers, etc. - 4/8/2008 3:34:31 PM   
gaRCfield


 

Posts: 1274
Joined: 5/20/2008
From: Burlington, VT, USA
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quote:

ORIGINAL: da Rock

Very few of our models need flaps. So they wouldn't "have a use for them" other than for fun.

If you want to have them, plug 'em in.



Fun! That's what I was looking for For some strange reason, I think the idea of flaps is fun.

Thanks.

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RE: Ailerons, flaps, spoilers, etc. - 4/8/2008 3:42:18 PM   
TRCX


 

Posts: 185
Joined: 7/15/2004
From: capetownwestern cape, SOUTH AFRICA
Status: offline 		lolyeah lol i just use the flaps for the hell of it and cauz it make for some better landings on the funtana. ive always wanted them too and since this plane has the ability to use them i just decided to program it in on the radio just for fun and because i think its cool lol if you take the dihedral out of the wings its going to be more unstable and will not self right so ild keep them in... taking the speed brakes off would give you alot more speed but you might have to use a different approach since the plane will take longer to slow down....
cheers
kyle

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Funtana S 40: ASP .52 series 3 Pitts muffler JR XP6102 JR R770S SPCM JR ES-539(rudder,elevator) JR Nes-537(ailerons,throttle

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