Hello all,

I have decided to get back into the hobby after about 3 years off (work and kids...you know how it is) and am in the process of taking up some of my old projects. I have a CG Super Chipmunk that I got completed "in the bones" and then left it. Now that I have taken up the hobby again I want to finish the plane but I want to make a few mods. I originally built it with the aileron servos in the wings and no flaps. After reading up on these forums I decided that I want to add flaps back in. The wing is already sheeted in with balsa and I did not install the original flap servo mount when I built the wing since I didn't think I wanted flaps. So, without tearing the wing totally apart or needing to buy a wing kit, can anyone help me out with how to install the flaps? My main issue is trying to figure out how to get the control rods installed into the already built wing since they have some bends in them. Also I don't think I have the original hardware so I would have to use some aftermarket parts to make the linkages. Thoughts?

Uh... I'm an utter n00b, and I hope someone will correct me if I'm wrong, but I *think* one thing you could do is get a 6 channel 'computer' transmitter and use the two aileron servos you already have on two channels and run them as 'flaperons'...

Yeah, I thought about using flaperons but I really want to put the flaps on this model and use the 6th channel for real flaps!! Plus, I have heard that this model flys really well with the flaps during landings...plus I just want a building challenge, lol.

Rockin. Goferit. Just thought I'd throw something out there that might save you the surgery... but I can totally relate to the surgery being The Thing (tm).

Hi,

Having built a Super Chippy with two aileron servos you will need low profile if you want to mount then upright between the ribs or build standard servos onto a hatch on their sides. No problem with linkages as it is then a straight throw of six or seven inches. There are numerous threads on how to hide servos using ply hatchs.

If you want a separate flap you will have to cut down on the aileron size as per the plans. If you have a computer radio why not use flaperons? I have done this on mine so I retain the full aileron length and still have flaps which are fun for carrier type landings or getting blown backwards in strong winds.

You will be very hard to please if you don't like this model

Cheers,

Colin

This is what I would do since it is already built. Cut the flaps free from the alieron, glue a piece of balsa to the top bevel of the flap and leave the bevel on the bottom. Get a "Y" harness for two micro servos and use the two micro's, one for each flap. Put the flap servos on a mount and run the push rod through the bottom sheeting and to a control horn on the flap. For servos I would use Hitec HS-81's, they are strong and lite.


Dru.

I used two micro servos for ailerons. I think they have 14 or 16 oz/in of torque. But when I started flying , a standard servo only had 16. So 2 micros are plenty.

As for flaps. Don't bother. This thing is a kitten.

Ok, before I go into detail, refresh my memory (It's been YEARS since I built a chippy).

If you build it with flaps, are the ailerons shorter than if you build it without?

Yes. I'm building a CG Chipmunk now (with flaps). To add flaps, the ailerons are shortened and the center portion of the trailing edge is also shortened.

ricknkim, I think you're going to have to do surgery if you want to add flaps. At a minimum, you'll have to cut some of the TE away and shorten the ailerons. You'll have to use some new balsa stock to make the flaps.

For control linkages, I'd think you could either just cut the whole TE away and install torque rods per the instructions or maybe use dual flap servos. Either way, you'll have to do some cutting. While I haven't flown my Chippy yet, I don't know if I'd want to do that much in the way of modifying the wing if it's already built. Just my $.02.

Mark

Yeah, that is about the conclusion I have come to as well. After looking at the wing and the plans, it looks like my options are as follows:

1) Cut a piece out of the trailing edge and put in new flaps. Install two servos on either side of the wing similar to what I did with the ailerons.
2) Make some sort of a connection between the two flaps, similar to what you do with an elevator. Then I would only need on servo to actuate both flaps.
3) Cut the whole trailing edge off and then install the torque rods as the plans show. Only problem here is I don't have those torque rods, I think they got thrown away when we moved.
4) Forget it and go with no flaps or flaperons (Boo!!!)

I think I'll head over to my local hobby shop and see if they have any torque rods available that would work. I think that going as per the plans would be the best if I could do it because I really don't want another servo hanging out on the bottom of my wing, I already have two installed in the wings. I don't think that cutting and replacing the TE would be all that difficult, assuming I could find some TE balsa stock that is the right size...decisions decisions!!! I am already doing major surgery on the LE of the wing, I have pulled off the front sheeting and the leading edge, it had some issues after I got done with it, the sheeting had to be sanded so much to get it flush with the LE that it got really thin in places and cracks easily. So if I'm replacing that I may as well put in the flap too, right?

Rick

Hi Rick,

Most hobby shops sell music wire and you simply bend up your own torque rods to your custom size. It is unlikely that you will find the correct size available but you could order from Goldberg. I'm sure some one will give you the part number but if not I can dig it out over the weekend.

The Trailing edge stock is also usually available however if not at your LHS it is quite easy but slower, to get around. Providing you can get the correct thickness (maybe laminate two thinner pieces?), just make up a beam of the correct cross sectional dimensions and razor plane and use a long sanding block to create the section/shape you need. Very theraputic with a cleansing ale.

PM me if you need the part Number.

Cheers,

Colin

Ricknkin
I am in the process of covering my second CG Chipmunk. I built in wing flaps on both. I did not use the torque rods that came with the kit but bought Dubro aireron torque rods and cut/bent to fit.
The kit wants you to mount the flap servo on it's side in the center section using the plywood servo support. I did not install the plywood support and installed the wing flap servo upright. Just keep servo as low as you can so that it does not interfere with servos mounted in the fuselage tray.
Did you mount the bellcrank system and run the ailerons off of one servo? I built servo mounts in the wings to run each aileron with it's on servo.
I think that it might be best to just cut the aft center section out to install torque blocks using the same material you plan to use as your wing flaps.

By the way what do you plan to power your Chipmunk with?

To answer your questions, I had already put in two servos in the wings for the ailerons. Just built a hatch similar to what has been shown on this site before. I finally decided to do the major surgery on the wing, actually went much faster than I thought with my trusty Dremel. At this point I have all the old balsa sheeting off the front of the wing, also took of the trailing edges and the balsa wingtips I had carved (didn't like the way they came out anyway). I bought some dubro aileron torque rods and bent them to fit. Plan to try and finish sanding the wing and install the torque rods tomorrow. Then I will replace the trailing edge at the proper length for flaps. Then all that is left is to cut some flaps out of the new trailing edge stock I bought and resheet the front of the wing. I also pulled off the stock leading edge and replaced it with 1 inch leading edge stock. Will have a lot of sanding to do, but I will have plenty of wood to work with, avoiding the original problem I had with the leading edge which was that by the time I got the sheeting sanded flush with the leading edge, the sheeting was paper thin and would crack with any stress at all. All in all I think the wing will be much better after the surgery than it was before...oh yeah, I bought a YS 91 a few years ago when I bought the chipmunk kit so that is what is in the nose. I'll post some pictures once I get it all done in the bones.