Not sure if this is really a scale idea or not, (at least i haven't seen it in any pics) but, has anyone ever attempted to install split flaps
on a piper cub? i have the GP .40 kit and am soon beginning the build (will be posting the progress) and was for the most part trying to get a lot of scale details into it, but also a few other details that i just like for looks. i have heard of others installing like fowler flaps and other configurations, but i want to be the different one. i was just wondering about the flight carachteristics how they would be effected. i was going to carve STOL wingtips also. i'm not really worried about any contests for the scale part, just wanting a cool plane. any input would be appreciated. [sm=confused.gif]

i was kind of curious on the power supply also. i curently have an o.s. 40 fx. damn good motor, but what about if i decide to clip the wing for aerobatics? i wouldn't mind building 2 wings if the evil half will let me have the money to do it, but buying the bigger motor is almost deffinately out of the question. so what about the .40 and aerobatics?[>:]

Seems like the thing to do would just be to kitbash the J-3 to a PA-18 (Super Cub). For that, all you'd need would be to convert the trailing edge from the inboard end of the ailerons to the wing root into a simple flap, and add a wider cowl. There are other differences, but for sport scale, those would do. The simple flap would be much easier to construct and make a linkage for. FX .40 would give you okay scale flight with full span, but I'd recommend something in the .50-.60 range if you want to clip the wings and have any aerobatic performance. If you're really wanting to just dink around and have something with real STOL, shorten the ailerons to about a third of their normal length (just use the outboard third, and make full span flaps from there to the wing root.

so, i'm curious if different designs of flap configurations make a difference on how they work and affect flight caracteristics when deployed and maybe how far should i set them up for. i had a GP RV-4 in commission (still have it), and built the flaps as they were designed to be but were not split flaps. would they still affect flight the same even with still having the upper surface of the flap stay the same as the entire flap dropping like the fowler style? am i confusing anyone, cause i think i just managed to confuse myself? well, back to cleaning my shop so i can start building. []

Flaps do several things: they modify the airfoil to increase lift and / or drag to allow the plane to fly at a slower airspeed, and to help slow the plane for landing. Whether they create more lift than drag depends on the angle they are deployed, as well as the particular design of the flap. A simple flap increases the camber of the airfoil, and alters the angle of attack by changing the chord line. Spilt flaps do the same thing, but are "draggier" because you have both the lowered flap and the trailing edge of the wing spoiling the slipstream over the rear portion of the wing. Slotted and Fowler flaps are "cleaner" because they allow a small stream of air through the hinge area, which smooths the airflow over the top of the flap, decreasing the drag. Fowlers usually move rearward as well during deployment, which increases the chord of the wing slightly. There is a point on either type where drag becomes greater than the extra lift, dependent on how far they are deployed. For example, for take-off you only use 10-20 degrees, where for landing you can go full deployment, as much as 60 degrees on some planes, to add braking by increasing the drag.

A model might benefit with as much as 40 degrees or so for landing. Using them may also change the flight characteristic of the model. Some will pitch up and some will pitch down with flap deployment, requiring a compensatory application of elevator to maintain the desired attitude.
Are you in the USAF, or family of one? I used to fly in and out of McChord back in the late '80's. I was in a medevac squadron, we flew in C-141B's, and had some friends there at McChord.

FYI, a full-scale Piper J3 Cub does not have flaps, typically uses a 65 hp Continental engine, uses a wooden prop, and the pilot sits in the back seat. A full Scale Piper PA-18 SuperCub has flaps, which are very effective, typically has a 150 hp Lycoming engine, has a metal prop, and the pilot sits in the front seat.

Also, the full scale J3 does not have an electrical system. So no lights, no radio (other than hand-held), and the engine is started by "proping" - turning it through by hand.

The PA-18 is a real STOL workhorse aircraft. It is popular for towing gliders, short field operation, float operation, etc. It is rated as "utility" by the FAA, which is just below aerobatic.

actually, i am in the air force and funny as it may be with me asking the questions about the aerodynamics of the flaps, i'm a crew chief on C-17 aircraft. i know how they work with the lift and drag on the real planes, but different typs of flaps work different ways as far as the coefficients, but i just didn't know how they would react on such a smaller scale, and not being exactly the same design and deployment. i was worried about the pitch up or down when deploying them and how far to set them up for as far as throws for take off and landing. i think i will start out with the 40 or so percent on the landing and maybe about 20% for take off. only because that's what my C-5 used to deploy to back when i was working the down at Travis. i think i'm wel beyond the scale thing, as i want to put so many of my own likings on it, but if i do decide to go with just scale applications, about the rib seams and the pinking tape and what not... i read that the seams have been reproduced on 1/4 and 1/3 scale aircraft using the 1/2 inch wide pinking tape, but i think the GP .40 size kit is about 5.5 scale, so how off would the 1/2 inch pinking tape be from actual scale? well, i need to get on with the plane, but thank you so far and talk later...[8D]

I used the pink hairsetting tape on my L-4, a little larger than your Cub, and it looks fine. You can find it in most any drugstore in the hair curlers / bobby-pins, etc section. It's self adhesive, has pinked edges. You need to use some kind of primer / sealer over it, and sand it a little before top coating it, but it comes out pretty nicely.

Must be a blast flying on the C-17. It was just coming on-line when I got out; my squadron, (31st AES) at Charleston AFB did the medevac eval and configuration on the -17. As good as the old Flyin 'Lizard was (C-141), the C-17 is heads and shoulders better.

I don't know how well it will show up, here's a pic of the taping I used. My L-4 is 84-1/2 inch wing

OK, I am a C-5 Flight Engineer and i am still unaware that the GALAXY has a 20% flap setting. It would be hard for the system to corelate with the 16 degree switches. How do you measure percent of the flaps for your aircraft? Uusally its percent of the available travel. Well hope you figure this out, because a cub flies alot differenty than a GALAXY. Nick

P.S- We only land at 40% when we have to due to mechanical defects.

okay panther guy, i appologize for the flap percentages on fred, i'm just a crew chief and forgot how right you engineer guys were all the time and was usually asleep on take off as soon as the gear broke loose and on landing i was just waking up ready to start my day o' drinkin.... the flap indicator on the dash (i believe that's where it was) was broke down in degrees so you could tell. but i'm not completely sure anymore, i haven't been on a fred in about 2 1/2 years. and where are you stationed and what squadron? i was 60 amxs at travis. anyhoo... i'm sure they do fly different from each other, i was curious of the differences between configurations on the PIPER CUB if anyone knew how each of them would differ. but since you totally dodged the topic of the forum i thought i would correct you on it.
khodges, thank you for the pics and info. it looks great. i was actually reading an article about the rib stiching and it was suggesting to use a heat gun and the 1/2 inch tape should shrink down to about 3/8". i finally found a hair supply store that sold the hair set tape and bought a couple rolls of it, so i may just cut a piece of it off and experiment. if it doesn't shrink, i'll just use it normal. not like i'll be putting it in contests and what not. unless they have one for the most unscale cubs. well, i gotta go find out how to measure degrees on my barney.

Gettin' a bit off-topic here, but......GOT-AW-MITEY !!! Full flaps and leading edge slats out on a Galaxy and you almost got an aluminum circus tent. Darn biggest airfoil I ever saw. When I was talking degrees, I was referring to the smaller planes with only a single panel on each wing.

We came into CAFB one day, I, as Medical Crew Director was on headset so I could hear the flight crew as we approached. We had assymetric flaps, one wouldn't deploy, and the checklist said in that event to land without flaps (from what I overheard). Normal landing speed for the Starlifter is about 110-115 kts, we touched down at 135, overheated the reverser buckets and cooked the brakes. Still had a little runway left, though. Hell of a ride, and we got to practice our emergency ground egress procedures. I sure did like the old Starlizard.

EMERGENCY!!! okay, i've been reading and reading and re-reading my instruction manual and staring at lots of pics about the bird cage cockpit of the L-4 aero machines and was trying to think of some way to build that into my (beginning to think) "crappy" great planes .40 piper cub kit. i really don't want to try to send the kit back to tower hobbies and get the Sig kit because i've been waiting forever for it to begin with. but do any of you guys know where i can get some sort of idea for the center wing box area on how to build the structure up for the rigidity and maybe a 2-piece wing and an idea of how to build in a working open and close door on the right side? the door is going to be the extremely tough part since one of the bulkheads is right there at the front of the cockpit where part of the door "would" be, i guess i don't REALLY need the door but it would be awesome if anyone else has an idea how to build it in. guess it really does pay off to do your research before you buy a kit and go digging around in it. darn manufacturers should all put there manual on-line somewhere for us to research before purchasing.[]

I've thought about it some; the way I see it, you'd need to re-engineer the wing halves to place the roots at the edge of the fuselage, make the wing sections that cover the top of the cabin into one piece and make it a part of the fuse by gluing it down. Then you modify that section and the forward part of the "turtledeck" into the green house, and make functional struts and their associated hardpoints on both the outboard ends of the wings (about 2/3 of the way to the tips), and another hardpoint at the rear landing gear mount for the inboard end of the wing struts. By the time you make all these mods, you've completely rebuilt over half the plane.

OR, just build it per the plans and make it an L-4C model. They were civilian Cubs pressed into trainer and coastal antisubmarine patrol service. You could re-cover it in Dk Blue above and gray underneath and make it an NE-1, which was the Navy version.

alright, i'm going to try to post a pic. hope it works.

holy crap!!!! it worked. not sure whos plane it is, but it is very very nice. a good picture of something i would like to do with mine. thanks to whoever's plane this is.

hey guys ive got a world models clipped ing cub with a 40 fx and it sppeds around real well, almost aerobatic. i think im gonna install the .46 os ax and see what happens but that should be plenty o engine!
Raf-

<span style="font-size: medium"><span style="font-family: Comic Sans MS">i see you are from mcchord. are you active or spouse of someone, or what? i'm in 62 MXS. this was my original thread, but i forgot my user name and all that fun jazz and had to recreate a new profile. where do you fly?</span></span>

I'm glad your back. Did you ever do the flap mod to your gp Piper Cub 40? My kit is on the way, and I'm hoping to be able to land this thing on floats on a small pond, and i think the flaps are going to go a long way to making that a safer landing. Do you have any pics you could post?

double post

<span style="font-family: Comic Sans MS"><span style="font-size: medium">hello everyone. i'm kind of back. actually in the desert right now, but still able to post every once in a while. i did set the wing up for working the flaps in, but in a haste to get the plane complete and ready to fly inan advanced schedule, i didn't set the flaps into the wing and of course the servos, either. all the modification is completed to use 1 servo per flap, 1 servo per aileron, and still the 1 piece wing. when i get back home and have the time, i will be cutting the covering away from the flap void and installing them.the only difference i did with the flaps, is instead of "normal" or slottedflaps, i opted for the split flaps. like on a P-40, or spitfire or something. slotted flaps are nice for slowing down or increasing lift, but the split flaps increase a lot more drag, slowing you down more due to the airflow being more disturbed parting from the trailing edge of the wing, versus the "slot" allowing airflow through to mix with the top of theflap surface, not disturbing it as much. </span></span>

Again, glad your back.  My brother is headed to the Desert this week.  Keep up the good work, and Thanks!  We'll look forwardto when you can get back home and post some more pics and show us how you did it.

I am designing a rc plane and am wondering what the width of the wing should be in relation to length