flyrotary@lancaironline.net Mailing List Archive

Hi Ed,

I made the ducts for my SOOB four times and found the easiest way with compound curves is BID cloth. BID cloth allows you to wrap around anything like rubber. I also made intake elbows for the carburetors the same way. All you need is 3 layers at most.

The other day I needed two 1 1/2" elbows on the one rotor. using Styrofoam for the core painted with water based out door Latex. When the Latex was dry I covert it with PVA mold release and made the lay-up with bid cloth and VE resin. After initial cure I put the heat lamp on it, and after it got nice hot the styrofoam started to shrink and the whole core fell out of the elbow. Much cleaner then using gasoline.

I hope this helps a little.

Richard Sohn
N-2071U
unicorn@gdsys.net
www.gdsys.net/WWWmembers/unicorn/

----- Original Message -----

From: Ed Anderson

To: Rotary motors in aircraft

Sent: Saturday, May 22, 2004 8:51 AM

Subject: [FlyRotary] Fiberglass Help!

Ok, you fiberglass types. I need some guidance. I can (and have) slapped resin on glass cloth and obtained a functional (if heavy) item. However, I am about to start work on my new radiator ducts and I would like to do better. My ducts will be approx. 4"x4" at the inlet and approx. 9"x10" at the core. There might be as much as 1 psi pressure on the walls (if I should ever be so lucky to go that fast).

There a some semi compound curves at the corners of the duct as it slopes inward from the top and bottom from the core to the inlet.

I need your recommendation about the weight and weave of the cloth. I have previously used the cloth tape as it was easy to manage, but it required several layers and it is a bit heavy. Like I said functional but not pretty nor light.

I would like your guidance on how best to apply the sheet to the mold. In the past, I basically wrap the foam mold in duct tape and the lay resin on it followed by raps of the cloth tape and more resine. I am told that using sheet rather than the tape and first laying it out on aluminum foil to wet it and then cut it in sizes say to fit a side of the 4 side foam mold with a bit for overlap with the adjacent sides was one way to go.

Any suggestions would be appreciated.

Ed

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC