porsche 911

I just received my WM chipmunk arf and will begin construction this weekend...the covering has loots of wringles but will use heat gun or iron to tighten the covering..what type of covering is this?? monokote or ultracote low or high heat????? the tail wheel set up does not look good to me instructions are not very clear on this...NO bearing in fuselage to take weight away from rudder???should this be replaced with something else???? Front firewall dosenot have thust line markings...can i draw an X from the 4 holes and this will be the piont????I will be useing dubro vib mount on my 91FX and need different holes( I wish they had not drilled the firewall).....anyone install a larger fuel tank???? the next thing is the retracts ( fixed gear version no longer avb.) I will be removeing the retracts and going to fixed gear and wheel pants has anyone done this changover and have instructions on how it was done???? I also whant to stop noseover problems i read about on this plane....I FLY OFF MY OWN GRASS FIELD AND RETRACTS ARE OUT ( NOTHING BUT PROBLEMS ) THIS IS A WELL MADE ARF AND LOOKING FORWARD TO FLYING IT SOON thankyou for your help........

ninefingers

My Feedback: (18)

911, You happen to be listening to a WM Super Chipmunk "expert". I've owned three and still have one (dont ask) and most of the things you mentioned are potential problems, looks like you been doing your homework.

Lets see where can I start. First off forget about the tail wheel. I always used the stock one and it never gave me probs. Just trim out rudder where you want it (flying) and then to make plane track straight on the ground just grab with vise grips (near swivel point) and bend it the way you want plane to go.

1. I'm not sure about what kind of covering but MonoCoat Missile Red and Signal Blue matches perfect. High heat ok.
2. Forget about firewall markings. With cowl on plane, engine shaft must line up with hole in front! Duh... Simple huh?
3. Fuel tank ok for Saito .91 and OS .91 Surpass.
4. I had so much trouble with retracts, I bolted a "dural" type landing gear to bottom on fuse (after re-inforcing it). No more bent landing gears! Do a search. I described it in-depth somewhere on RCU. You might want to do that anyway. Another problem you havent noticed yet is flemsey control rods.
5. The nose over problems will be corrected if you up-grade to (4.) above. If you keep re-tracts, the problems is caused by all the down trim the plane needs to make it fly level. Just get use to applying up-elevator when taxing (you should do that anyway)

Anything other questions about WM SC ask away!

ninefingers

My Feedback: (18)

911, to elaborate on the landing gears a little more, if you upgrade to "fixed" gears on wing, try to bend them forward a little. You should see part of them from above the plane looking down. This should help nose over.

When you get tired you straightening them all the time, try what I said above!

I used one or those new type fiberglass dural landing gears. Put on bright red 60 size wheel pants, not scale but snazzy! .

fenderjw

My Feedback: (83)

I just bought one of these at a swap meet, but since its not new, I didn't get the assembly manual. I've checked the other RCU threads, but I don't see the info that I need posted anywhere. My chipmunk is nose heavy with an OS 91 FS and I need to re-balance it. Where is the CG supposed to be? Any assistance appreciated.

Thanks
Jim
[email protected]

MANFRED

My Feedback: (27)

911, they make a fixed gear version with wheel pants, perhaps trade yours in. I have had no problems with the retracts. Great flying ship with a .91 surpass II. Tailwheel does suck though! CG pretty much like most semi-scale birds, right on the spar.

LUNATIC

My Feedback: (4)

The CG is 105mm (4.13in) behind the leading edge. The covering they use is Ultracote. I have a Thundertiger 91 on mine with no additional weight needed (balanced perfectly). I had several hard landings with the stock tailwheel no problems so far. I also fly off a grass field and fixed gear is a MUST. Took me about 1 hour for the fixed gear conversion, well worth it. Good Luck! You will love this plane.....

fenderjw

My Feedback: (83)

Thanks for the info on the cg. FWIW, I have the factory retracts installed and I fly off grass. Did the mods outlined in anoter post about offsetting the gear more forward. It flies like a dream. No problems with the retracts on grass (other than occasional nose over taxi-ing back to the pits after landing). The gear were a pain to regulate, but with a little patience, I got mine working reliably and this is my very first set of retracts.

Thanks again
Jim

csandt051196

My Feedback: (35)

You mentioned that you needed a lot of down trim. I have my second ready to go. I fly off of pavment so I am going to give the retracts a shot.

My real question is that the first one died a very ugly death because I balanced it up right and added to much tail weight. With the second I balanced upside down and added 1/2 oz to the tail. It really did not need it, but it made me feel better.

How much down trim do you have to have to fly it? Will it be eratic with no trim on the first flight or should I put some in before I take off?

Thanks
Scott

jabowil-RCU

My Feedback: (9)

I've been flying my WM Super Chipmunk w/YS91FZ about 4 months. Great flying plane! And beautiful in the air and on the ground. I used all the stock hardware which has been fine. I fly off a paved runway and at first had a lot of trouble with the retracts, bent struts almost every flight. Learned to land this plane a little better (keep the speed up!) and installed a new set. Now they are fine. Most of my flights were with the retracts down. I was afraid they might not come back down or stall the servo if retracted because of the bent struts. But with the new set I started flying with the gear up. Big difference. Plane flies significantly better, rolls in particular are much more axial. I like it even more.

Also the YS is a fine engine for this ship. Mine will go up until I can hardly see it, huge loops and cuban eights. I also have to fly with a little down trim, but it is no big deal.

Be careful handling the sheeting around the wing root, it's pretty delicate. Good luck, you made a good choice.