nuvaring

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In all my 25 years of builidng and flying, this is the first time I'm crossing this bridge. Looking for advise and tips for laying up this cowel. Once I'm done shaping and sanding I'll pop it off to do the glassing.

Any suggestions for laying up the cloth, what weight cloth and resin to use?

Thanks

soarrich

My Feedback: (98)

Do you want it to overlap the fuse, or butt up to it?

I've found for a one off male mold you don't have to get real fancy. What you have is close to done. I've taken something like you have and used packing tape to cover the foam, then waxed that. Once you buff the wax lay up your cowl using strips of 2 to 4 oz cloth aiming for 8~10oz thickness. Use WEST 105/205 you can get at any boat store, it's epoxy, you do NOT want polyester resin. After the epoxy has cured overnight, (I set my stuff on my water heater), you cowl should come out easily, if not a little gas onto the foam will dissolve the foam and the tape will keep the goop off you cowl.

If you want it to over lap the fuse a inch for mounting ease, just do like above, but leave it on the fuse and run the tape from a couple of inches back on the fuse. The only change would be wait until the epoxy is partially cured, about 3 hours it should be about like cheese, then about a inch back on the fuse run a razor blade around, just cutting straight in, trying not to go too deep that you cut into the fuse very deeply this gives the back of the cowl it's edge. It's much easier to cut fiberglass at this cheese stage than waiting for when it's cured. Now would be the time to take the excess off the fuse too.

nuvaring

My Feedback: (6)

Rich,

Thanks for the info... Hope to glass it this weekend. I'm guessing two layers of 4oz cloth should do the trick. I'm planning to make the cowel flush with the fuse instead of overlapping. Once I pop the plug off the fuse, I may scribe and sand off a small amount off the plug where it meets the fuse. Hopefully if I get it right, I'll end of with a nice flush fit.

Thanks
Gus

soarrich

My Feedback: (98)

If you pop the cowl off, stand it with the nose up, then take a hot wire .030" and cut the cowl into 1/4s vertically, then rejoin, the kerf should subtract enough foam that when you do your lay-up it will be flush with the fuse.

T_om

If you are going to all the trouble, you may as well do it right. A male mold is a PITA. You will spend forever sanding it to get it right. And you are faced with having to reduce the plug diameter by the thickness of the glass layup... which I will be willing to bet you do not know. It will look funky as it will be VERY difficult to carry a smooth curve through that joint.

A female mold, however does away with all these problems. Get your shape right on the plane, as you have done, lay up a female mold, then the re****ing part pulled from the female mold will fit exactly... with the additional benefit of you still having the mold in case of accidents to the cowl later... just pull another part.

There are TONS of instructions on this site and elsewhere on making a female mold.

Tom

Waterlogged

I will try the foam method myself and see if I can make a mold out of it. I'll post the FG layered foam plug tomorrow after the epoxy resin cures and it's sanded/primered.

This is a Hobbico NexStar ARF converted for electric. I made my own CF tube 1:1 CF/FG 3x around a 2.375in pvc pipe and vacuum bagged for 48hrs= 2.50in dia tube. The tube has 8 "fingers" that protrude through the firewall and epoxyed in place, with FG cloth around the front of the firewall as seen in the pics. This mod gives enough clearance to swing a 14" prop with stock landing gear.

Also, the tube dirrects forced air over the outrunner and the ESP mounted inside.

More on another thread[link]http://www.rcuniverse.com/forum/m_9209307/anchors_9209307/mpage_1/key_/anchor/tm.htm#9209307[/link]


-WL

soarrich

My Feedback: (98)

That's one strong mount you've made. Looks good.[sm=thumbup.gif][sm=thumbup.gif]

Waterlogged

Grrr.... the 4th coat (FINAL) of white epoxy caused the others to lift, it's all a curdled mess. I'll have to scrape off and wait a week for a full cure, then sand. At least the next run will have a smoother result, since I'll know where the "trouble" areas are, humm... maybe that's a good thing. =)

Oh! It's a damn perfect fit, I was shocked!

Off to start the wings!

-WL

Waterlogged

All done -WL

soarrich

My Feedback: (98)

Looks really good.[sm=thumbup.gif][sm=thumbup.gif]