More on Flaperons and Spoilerons! (Class 10)
Posted March 19th, 2009 at 10:35 PM by ThursdayBeginnerBlog
Flaps
Usually a plane will have an aileron on the outside of each wing and flaps on each side of the inside of the wing. When he lands both inside flaps go down giving the wing more lift. He can still use his outboard ailerons normally.
Flaperons
In this case, there is just one big aileron that doubles as flaps. So both flaps go down for more lift and then they move some to act as ailerons. The ailerons and flaps are now mixed together.
How Flaps/Flaperons Work
The center of gravity (CG) or balance point of a plane is like a pivot, or teeter-toter. If you push the tail down, the nose will go up, see. If a control surface such as a flap is CLOSE to the CG it will not pivot because its lifting right on the pivot. If the flaps are far away from the CG, they will cause the plane to pitch down because they are lifting the back of the wing up, pivoting on the forward CG which is then causing the nose to go down.
Benefit of Flaps/Flaperons
If your CG is close to your flaps, flaps will not pitch your plane up or down, but will merely cause you to FLOAT UP. This is great for shorter and slower take offs and landing.
Downside of Flaps/Flaperons
If your flaps are behind your CG they will cause you to pitch down. Also, if you are flying with your nose up some (high alpha) they will cause your wing to stall sooner!
Planes They Work Good On
Any of your standard planes they work on: Yaks, Cessna, P-51s, stuff like that. Anything that has the center of the main front wing close to the CG.
Planes They Don't Work Good On
Weird jets like the F-35 and F-22 have their trailing edge of their wing SO FAR BACK its pretty much the back of the plane! So, if you put FLAPS DOWN on these plane they will lift your tail, and drop your nose. This is the case if you try flaps on these planes in the RC world. If these planes are way tail heavy, you can get your CG point closer to the rear of the wing and it will lessen this.
This is why if you buy the EDF F-35 or F-22 you can use the ailerons as a second set of elevators/elevons. They are so far back behind the CG they act as a second set of elevators!
--------- Part B Spoilerons ---------
Spoilerons
For the sake of what we are talking about here and what we do, these are basically flaps or flaperons just upside down.
How Spoilerons Work
Same deal as above flaps as far as how they pivot or lift around the CG. In this case since they are blowing the air the other way, they will not lift your plane, rather shove it down!
Benefit of Spoilerons
They are most often used as air brakes. If they are right on the CG or close to it, they will not pitch the plane around rather just shove it down! With a slight pitch up, the plane will stay level and simply slow way down.
What we use them for is high alpha! When a plane is flying straight and level with the horizon with its nose kicked way up, the wings start to stall out as they approach about 35 degrees or so. If you have your flaps down you now have increased the angle of attack of that control surface to like 70 degree angle of attack! This will stall the wings out right away!
This is why flaps do not work for high alpha (at least in RC) and also why if you roll to the left doing high alpha, your right wing will stall out as your aileron comes down to roll the plane. So, you are doing high alpha, you roll to the left, and it stalls and rolls over to the right! Big problem here!
By kicking back the spoilerons you now can keep your wings at say 35 degrees angle of attack but your control surfaces are now kicked back to say 5 degrees! Now you are just like sitting on them as you fly! You roll to the left and the plane is now going to roll to the left.
By hitting spoilerons while doing high alpha you simply regain and keep aileron control and stop your wings from stalling! This is why I use them so much on my jets!
Downside of Spoilerons
Guys make fun of you at the field and say your flaperons are upsidedown.
Planes They Work Good On
Any jet that has a wing that's way in the back such as the F-22, F-35, Su-35, etc. This gives them great high alpha control. Though, this trick also works for Yaks and such doing high alpha as well!
Planes They Don't Work Good On
On a "normal plane" like a sail plane, Cessna, Yak, war bird, etc they can be used as high alpha too but better used as air brakes for these types of planes.
Question for the class:
If spoilerons work so good for RC high alpha (which they DO) why do we not see the high alpha jets like the Su-35, F-18, and F-22 using them?
Please leave your answers in the COMMENTS section of this page (see below)!
Next week Thursday at 5pm PST we will be filming the show LIVE again HERE and will be talking about center of gravity, why its so important, and how to balance your plane!
Products Mentioned in This Video:
ExceedRC F-35
ExceedRC F-22
ExceedRC F-18
Art-Tech Su-27
Multiplex Blizzard
Wild Hawk
New Super Small On board Camera!
MEGA JET V2
We used Flaperons in this video:
We used Spoilerons in this video:
We used both Flapersons and Spoilerons in this video:
Total Comments 9
Comments
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When will the SU-35 be available? I need a couple of them.Posted March 19th, 2009 at 11:51 PM by Go4it 
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Hi Dave,Val and Keith, excellent work as always.
I have spent the last hour or so researching/investigating your question, difficult one and I'm certainly no expert. After much pondering I put it down to aerofoil,wing design and flybywire systems.No "older" jets can do "high" alpha stuff,above 16degrees without risk. As far as RC jets are concerned,your example of the flaperons going up during high, this I guess reduces the risk of a stall by "reshaping" the aerofoil section of the wing during these manoevers,less of the barn door effect. Modern fighters with their super critcal wing designs and computer controlled flight control surfaces,LE slats,flaps,thrust vectoring etc etc takes away this risk of wing stall. Our foamies and depron jets to have a very simple aerofoil and wing design, some cases virtually flat sheets.
Does this makes sense???
Regards, Nick. (NickUk)Posted March 20th, 2009 at 02:28 AM by NickUK
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Just another point,like you said in the show, the subject of centre of gravity has alot to do with it as well,thats another story all together.Anyway its 2:42 am and I know have brainache,this topic will be flying around me head as I sleep,Take care,Nick.
Posted March 20th, 2009 at 02:43 AM by NickUK
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Hi Dave, great and funny videos.
Just registered to answer your question.
The only reason why you use spoilers for high alpha flight is: It makes the flight more stable. The disadvatage is: less uplift. For you this stability is more importend than the uplift because that small plane (+ remote control) is yery instable and quick ... and the uplift is less importand because the low wing load.
The real jet planes have a much higher wing load, so they need the uplift more... and with the centre of gravity more in back, a much bigger, heavieer (means slower) plane, slats at the wing and much better onboard control systems they have much more stability control.
Just remember: High alpha flight is in fact a controlled stall situation.Quote:NickUK wrote:
Modern fighters with their super critcal wing designs and computer controlled flight control surfaces,LE slats,flaps,thrust vectoring etc etc takes away this risk of wing stall
In normal flight a wing gives only 1/3 of his uplift from the air flow below the wing and 2/3 from the air flow above.
Wing stall you have when the air flow above the wing is disturbed by too high alpha.
Thats what happens in high alpha flight. You have only that one third of uplift, the rest has to be generated by the power plant.
The "only" difficulties are: controlling that wing stall and the transitions from and to normal flight.
... so it should beQuote:... takes away this risk from wing stallPosted March 20th, 2009 at 10:59 AM by Inder-Nett
Updated March 20th, 2009 at 11:09 AM by Inder-Nett -
That seems to be a great price on the mini camera. Everywhere else on the web it is $100 with no memory and lower video resolution. You're showing Grayson selling it for $89 with 2GB and 640x480.
Posted March 20th, 2009 at 11:25 AM by FoamyDave
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Nice mini cam. But it isn't a wireless transmitter, now is it?
The one that I have is very much wireless. Plus, it's a buttload cheaper. But not much to speak about the video quality.Posted March 20th, 2009 at 07:18 PM by Kurtank
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Hi guys for the question of the day, i think they don't use them because they can over power the need for it with a stronger engine. same reason they can have a full array of computers on the harrier to make it work as a vtol.
now in response i've got a question for you.
Why did you do the air brake the way you did.
it makes more sense to me if the air brake was angled like this \ with front of the plane
here \ air brake, back of plane.
there are planes that do this in the back around the engine. i made comment of this on the youtube page but a lot of people were over running that so i thought I'd leave it here. look for adequateautocrat's comment on that video and you'll find it. and killshot knew the name of the plane.Posted March 20th, 2009 at 11:14 PM by V-Vendetta
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Hi Dave, Val and Keith,
I really enjoy your shows. They are very informative. I found your site about 2 weeks ago while watching videos on Youtube.
I know that you had mentioned stalls last night with regard to speed. Actually airplanes can stall at any airspeed and at any attitude. Every wing is designed with a critical angle of attack. Once the wing surpasses
the critical angle of attack, the plane stalls. The angle of attack of a wing is based on the angle between the chord of the wing and the relative wind. The cord of the wing is a straight line from the leading edge of the wing to the trailing edge (as you would look at it on the model that you were using last night}.
Another term for high alpha would be minimum controllable airspeed. When I was training for my license
we would practice flying minimum controllabl airspeed. It would be the lowest speed that you could fly at while flying without descending. It would be barely above the stall speed of the plane. The controls were very sluggish and would require greater movements to maneuver. I rembemer flying one day with high winds. We flew against the wind and we were actually going backwards.
I look forward to seeing your future shows.
Continued good luck in the future.
Regards,
DonPosted March 20th, 2009 at 11:45 PM by Aviator_Won
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Go4it,
That's just a one time experimental plane. We don't be doing PDFs or kits for that one sadly. Our buddy Scott Lott is working on one that may be a PDF! So we might have something in a few months.
NickUK,
Yes, its the F-18, F-22 and alot of the Russian jets that can get way up there in high alpha. I know the F-16 and F-15 can't get very high for example.
With the RC planes we have tried it with both flat depron wings as well as planes with airfoils such as the F-18 EDF from Nitro. Our results are always the same regardless of size of RC plane or type of airfoil: when we do spoilerons we always get better high alpha!
Inder-Nett,
Oh hey cool, thanks so much for joining us and helping out!
Ok! THAT makes alot of sense!!! Yes, we are flyng motorized kites practically, and the full size planes weight thousands of tons! So yes, when they are going 45MPH at a 50 degree angle of attack, they are going to need all the lift they can get to STAY LEVEL!
They need more lift than they do stability at that point, unlike our feather lite, overpowered, RC planes!
Thanks so much Inder-Nett!
FoamyDave,
Yes, it sure does! Good to see that Nitro has the CAMERA as well as Grayson. I hope to try this thing out soon once Val is done getting all the tech set up done for the live shows! Poor girl has been working 4 weeks just to get these new live shows to work!
Kurtank,
Yes, after I master this camera I'd like to try those FPV (first person view) ones! I think that would be cool. Put it on a heli, hide around the corner and drop paint balls on Keith when he goes out to get the mail.
V-Vendetta,
Yes, there are definitely better ways to do the airbrakes. We did it that way first just to try it how the scale full size guys do it and then use that as a standard to judge other ideas (we had to start somewhere). I've really learned alot form it and see that different airbrakes are gonna be best for different planes and applications.
With full size airplanes, they are far more less powered compared to the RC ones. Most RC planes can produce twice their power to weight ratio where just a few full size planes can produce more thrust than their body weight. I think Inder-Nett had a really good point that they need their wings more for lift than they do for stability cause they are so heavy.
Aviator Won,
Hey thanks for joining us Don! Yes, good points about any plane stalling at a certain speed. We have found that when any of our planes stall at say 30 degrees, when we then hit the spoilerons, we can get like 15 degrees more angle of attack! Which also meant that we could slow the plane down even more!
I know what you mean about flying backwards in a head wind! That is very cool and we are tapping into that principle with our STOVL project. We plan to use some head wind for stability at super slow speeds!
Posted March 26th, 2009 at 08:43 PM by DavePowers
