sandman450

I am working on my new Skyshark P-40N and bought the complete Sierra Precision Retract System including wheels. I am trying to install the 5.5" wheels that shipped with the retracts and they won't fit down into the wheel wells on the P-40N. Either the retracts are too long or the wheels are too big. Any of you guys that have built the P-40N from Skyshark run into this situation. I have tried to contact Darrell at Sierra for almost 2 weeks with no replies so I am hoping you guys can help me figure this out. Any help is very much appreciated.

All Day Dan

My Feedback: (5)

The P-40 had 30 inch wheels. At an advertised scale of 1/5.5, the 5 1/2 diameter wheels are the correct scaled size. Are they too large for the opening or are they off center? Dan.

sandman450

Hi dan-Thanks for the quick reply. They are way off center and bang into the sheeted wing surface. They appear about 1/2" too big. Is there some setting where I can make the reatract leg shorter?

Corsair 29

I have this same setup using the sierra retracts and the 5.5 inch wheel. The only major mod I had to do to get the sierra retracts to fit was on the wing tubes. I had to cut a notch on the tubes so the retract mech would seat properly. Of course then you worry about the wing folding up in the air, well it hasn't. I've had a lot of flights on mine so far it it is a joy to fly her everytime.
Here are some pics of my sierra retracts with the 5.5 wheels, so you can get a visual of mine.

All Day Dan

My Feedback: (5)

It sounds like you have two problems but it looks like corsair 29 got a good fit. Take a close look at his images. Maybe you can see a difference. Dan.

oriole

My Feedback: (19)

http://www.rcuniverse.com/forum/m_52..._1/key_/tm.htm

There are several threads on the skyshark p40. The above is an excellent build thread for reference.

I went with the 5.0 inch wheels, since I had read somewhere that the 5.5 inch wheels wouldn't fit in the wheel cups. I also had to enlarge the wheel wing holes slightly to allow the wheel cups to be pushed back further towards flaps thus allowing the Sierra retracts to fit when retracted up into the wing.

The aluminum tube cutting is a design flaw, and will have to be cut, no matter what Retract System you use. The above thread addresses.

Oriole

sandman450

Guys-Thanks for the replies. I know about the tube having to be cut. I am just trial fitting the retracts right now without the wing tube in place. I did notch the wing tube hole already so the retract is not hitting anything. The strut seems too long or the wheels are too big. I may have received the wrong struts from Sierra. I have studied Fockwulfe's thread extensively for my build....even printed out the whole thing and stuck it in my P-40 Instructions.

Corsair29-Thank you for posting the pics.

kenair

My Feedback: (10)

I've acquired a built but unflown Skyshark P-40 with the Sierra gear, it has the notch cut out of the wing tube. Since the last post on this thread was almost four years ago, any failures n the wing tube notch? thanks -ken

ccostant

My Feedback: (38)

I have the Sierra gear with 5.5" wheels. I chose to strip my wing and glass it instead. In the bash I did not use the kit wheel wells and if memory serves I did open up the wheel wells some for better clearance but I believe the 5.5" wheels would fit with the original wheel wells. With regards to the tube I haven't had any issue. I have a G62 in my P-40 and it really hauls the mail, very fast. I've put it through many high G maneuver without any problem.

kenair

My Feedback: (10)

Did you cut a notch in your wing tube as Corsair 29 did to fit the Sierra retract?

ccostant

My Feedback: (38)

Yes. It's the only way to get the Seirra gear to fit. My wing may be a bit stronger because I fully sheeted the bottom since I was fiberglassing it.