I need a little advice from some of you veterans. I'm building an old Midwest Mustang .60 which has strip ailerons actuated by torque rods. I'm planning on splitting the ailerons and making flaps. The construction modification should be relatively easy. My questions are: How much of the aileron should now become a flap? Is a mini servo enough since flaps are used at low speeds?
This plane will now have 7 servos and I'm using mini's where possible (Throttle and retracts - air) and would like to use them for the flaps if possible.
Any and all advice is appreciated.
Thanks,
Jeff

You are undertaking a major redesign of the control surfaces - this has consequences... [:@] [:'(] [&o]

IF POSSIBLE; IF YOU HAVE A COMPUTER TRANSMITTER - do not cut the ailerons just reprogram your Tx to allow flaperon action of the ailerons.

This will save you lots of work (Cutting, rehinging, running new lines, and new servos). All you need to do here is add a servo to each aileron and you are done!

Ultimately the decision is yours. Personally; I have a Mustang with no flaps and I have no problems taking off or landing - why do you think that you need Flaps?

I agree with BBBAIR. I've used that method and it works very well, plus, it's an easy mod. (if you have a computer radio.)
Randy

If I go the dual aileron servo route- my original intention, why not just cut the aileron stock and utilize the original torque rods to make flaps? Ya'll aren't trying to talk me out of this are you?

Just a thought... I guess I could mount 2 servo's side by side - one for each torque rod. Hmmmmm....

..............Just a thought... I guess I could mount 2 servo's side by side - one for each torque rod.

========Now you're cookin'! That's exactly what I did with my King Kobra, and it works excellent.

And, you did ask for advice from veterans! I'm veteran enough that I go for the "KISS" principle.
You said it had "strip" ailerons. By that, I assumed that it is not a scale airplane, which is what I based my suggestion on. If it were a scale plane, separate flaps would probably be in order.

What ever way you decide on, get the airplane way up in the air before you deploy any flaps to see how the airplane will respond to it. All of them act differently. Depending on the amount of flap used, some will "pitch up" when the flaps are deployed, and you have to hold the nose down all the way to the runway, and others will pitch down, requiring holding "up". And, there are a lot of variables to all of what I've just said.
Have fun with it,
Randy

If you insist on having separate flaps there are several things still to consider;

1. How many hinges are on the strip ailerons?

2. Where are they located?

3. Where are you planning to cut the aileron? You will need at least two hinges per flap, and perhaps three on the remaining aileron.

4. Are the hinges close to the ends of you're new control surfaces? You don't want to induce any flutter...

Now; you want to use two servos to control the flaps...
WHY?
-Extra weight, wiring and expense!! - not good!
-One servo, light simple and inexpensive - very good!
How?
-Get some pinao wire, and make a simple yoke (think of a 'Y' that starts at one point and then goes to two places).

Finally;
Yes I AM trying to talk you out of this modification, if you have a computer radio you can do this easily with little effort. If you do not have a Computer radio - the question becomes; Why do you feel that you NEED flaps?

It sounds like the model has just one servo driving the ailerons right now. If that's the case, no computer radio in the world is going to be able to give you flaperons with just some programming. And that's a shame because I think it'd be to your advantage to test the model in flight to see if your ailerons are going to have enough surface to effectively work as flaps.

Strip ailerons usually don't have much chord. I think most effective flaps have lot's more chord. They're that way because to be effective they had to have more chord.

If your ailerons are driven by one servo right now, the servo is probably centered in the wing and it's horn is "between" the two torque rods. The dead simple and easy way to keep from having to move the servo but drive the two torque rods equally would be to lock the two rods together and drive just one of them. Take a thick piece of plywood and drill two holes in it. The holes would be a snug fit to the torque rods. Slip the ply down over the two rods and glue with epoxy. Keep the flaps lined up while the epoxy cures. Leave enough of the rod sticking out above the ply to connect to one servo arm. The ply ought to be thick enough to cover most of the rods, top to bottom, but not bump into the wing (bevel the bottom of the ply for clearance) nor interfere with the push rod (bevel the top in that area).

To get some idea how your ailerons are going to work when they've had about half their area stolen from them, test your roll rate. Jack the aileron throw to max in stages and roll the sucker some. As you shift your linkage to get more and more aileron throw, the roll rate ought to get faster and faster. If the rate seems to stop increasing with any change, the ailerons have reached their max effectiveness. They're probably "stalling" at that deflection. Note that deflection. And try each test at low speed after seeing an adequate high speed roll. If you don't have quicker high speed roll with any change, then do your low speed tests HIGH UP. Now make a value judgement. If the roll rate never scared you, then half the aileron area isn't probably going to give you "good ailerons", and half the ailerons working as flaps probably aren't going to give you "good flaps". But if the sucker got really fast and maybe a roll a second or better, you might get good flaps and aileron out of halving the aileron area and using half for flaps and half for ailerons.

Sounds like a fun thing to do.

My guess is that if you just cut the ailerons for flaps/aileron, you probably will wind up with marginal ailerons at low speeds and "less than hoped for" flaps.

BTW, flaps not only have large chords, but they're usually driven to angles way beyond what ailerons see. I think the NACA specs on flaps showed their effectiveness came at better than 50-60 degrees.

And btw, cutting an aileron in half won't give you an aileron that is half as effective as it was before. It can be appreciably less.

Good thing about your experiment is that once you get the new aileron servos in the wings you can go back easily. Just pull the flap connections and glue the flap/aileron gaps back together.

Let us know how it worked out. It'll be very interesting to follow.

Hey Jeff,

I did something similar to a Twinstar for the heck of it. It is easy to do. Please see the following thread.

http://www.rcuniverse.com/forum/m_27...anchor/tm.htm#

Hope this helps

DD

Thanks for the advice. I'm still mulling this project over. The fuse and tail feathers are complete and now I just stare at the wings and debate, do I just go ahead and cover the wings or get out the saw and start making flaps...

DrDeath, your project is exactly what I have in mind. - thanks for the pic and info. How did it fly? Did you have to increase the aileron thows? How effective are the flaps?

Hey Unballanced,

Sorry it has taken me so long to reply, I have been on vacation down in Florida. Can't tell you how she flies as I got tired of the project and the plane after I completed it. The twin engines needed more breaking in and the cheap plastic spinner cones that came with it broke during my first day that I started the engines. I have the plane up for sale, and after replacing the two cones I am thinking about keeping it after all. The engines have only two tanks through them and I wasn't able to sync them enough to get a reliable first flight. So, maybe after the first of the year, I may try again.

DD

Unballanced, I not only won't try to talk you out of it, I will give you a whole-hearted GO 4 IT!

I have used this method on several airplanes and it works VERY well (As opposed to the suggested Flapperons which I have used twice and will never use again! )

Cut just less than 1/3 of the inboard side of the ailerons for Flaps. This will leave you with plenty of aileron control and some very effective flaps.

I'm glad to hear someone saying "Go For It!!!"

I've been thinking of doing the same thing to a 4-Star .40 sitting on the bench...Not because it needs it....just to see if can be done... Besides what's the worse that can happen..[] take the flap servo out and glue the flaps back to the ailerons

ARE YOU COMPLETELY UNBALANCED?
Sorry, I couldn't help myself, just kidding.
I say go for it too, there are many planes with strip ailerons and flaps. My Telemaster for one. They work very well. When you bevel the flap for movement just remember to slant it from the top back !\ so you will have lots of deflection. And the advice about being 2 mistakes high when you first try them is good too. Once you find out how it reacts you can program a little elevator to flap to compensate for you. And don't be afraid to try knew stuff, it's half the fun!
Have a safe and Happy New Year guys.

Floater

OK - Fair warning, I'm getting the saw out!!! OK, what about a flap servo? Will a Hitec HS 81 mini be OK? Same for the Ailerons? How much torque do I need?

I'm not familliar with the HS 81, but in general, I would say that you won't need anything bigger than a standard servo (1 for ailerons and 1 for flaps)

Noiw I'll probably get blasted for saying that, but I've flown 60 size planes with one standard servo for ailerons for MANY years. The newest "Trend" is for going to a 2 servo setup, and it may be nice, but it's not a necessity.