Mike James

Hello everybody,

For those of you who build composite jets that come from the factory requiring you to cut the gear doors out...
In previous planes I've molded for retracts, I molded the gear door outlines into the fuselage, but also made shallow female molds and included separate doors, so the builder could cut out the doors in the fuselage with no worries of damage. Apparently though, many of you are good enough, (and the manufacturers know it) so that they're just providing the molded-in set, which you cut out. So...

What do you find to be the most precise method?

I'm sure it can be done with the obvious tools... X-Acto blade, perhaps heated, to cut smoother, a Dremel cutoff wheel, and maybe even a razor saw. Would some of you be willing to share your methods of doing this ? (photos would be great)

Thank you for any help you provide.

lov2flyrc

My Feedback: (24)

Have a few techniques for this procedure, really depends on the fuse and shape of the door. A Dremel with a thin diamond cutoff wheel leaves a nice small gap. Razor saw with backbone removed and dimples ground off works quite well too. Usually just tape the door outline and cut with either of the above methods. If cutting curved doors or speed brakes I use a very fine point carbide bit in the dremel making multiple passes till the glass gets thin, then relieve the cut with a #11 blade....
Todd

mr_matt

My Feedback: (10)

Hi Mike,

I put my technique in this thread:

http://www.rcuniverse.com/forum/fb.asp?m=2412485

But if you are used to making seperately moded doors, that is a great way to go. Yellow has nice moded doors.

I just paid $125 bucks for a set of aftermarket molded doors for my MIG, I would always rather have seperately molded doors and hatches.

Good luck,

PS how are you going to align and join the halves of that fuse?

Mike James

Thanks, Todd and Matt!

Not obvious in the photos, but the molds have several alignment things built in. First, there is a firm fit with the nose section, from the wing leading edge forward, due to the sloping nose. There are also holes for machine screws drilled all around that flange...done before mold separation. The rear "exhaust" (spinner backplate) area locks together, and when we actually make parts, the side pieces also screw to the top and bottom mold halves with machine screws, and hold all four pieces together. There just wasn't room for the usual "pegs and holes", but I take the alignment issue seriously, and worked it out. I just checked that again tonight, to make sure that I wasn't insane. It's fine.

I probably will get a whippin' for posting these photos here, but since you asked... Here are a couple of photos of the interior of the molds, one looking forward and one looking aft. (Side pieces not attached here, for clarity. (It's dark in there!)

Thanks again for your opinions on the gear doors. We'll probably go ahead and mold separate doors. That way the super-neat guys who can cut them free perfectly will have two sets, and the sloppy cutter will still get useable doors too.

I welcome anyone else's ideas on this. Thanks again, Todd and Matt.

K Jorgensen

My Feedback: (2)

Hi Mike

I always do like Todd. With a Dremel and a diamond cutoff wheel. But I always cut the hinge line first. And then glue in the door hinges. And then I cut the rest of the door free. That way you always get a perfect fit. I will also giver the area where the door is an extra layer of carbon fiber. To make the door nice and stiff. I glue my door hinges with CA. If I then have to make a gear up landing and the doors is still open. Then they will just break of with out any damage to them.

Mike James

Thank you, Kim. Good ideas.

Made the gear door molds today...

Gordon Mc

My Feedback: (11)

Agreed - that way, if someone loses a gear door for any reason (and there are lots of 'em), it's really easy for you to send them replacements.

Mike James

I agree too, and it's nice to see someone else saying it.

I've recently figured out the skin hinging thing, and was about to become over zealous and use skin hinging for the gear doors. Then I realized that the skin hinges, if snagged on grass or something else, could cause a lot of fuselage damage. Better to just re-glue the hinges!

I appreciate the input from all of you. Thanks!