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Replacement Cowl


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Hello,

Would anyone know a shop/site where I could get a replica 60 size P47 cowl?

My H9 P47 is still in great condition except for the cowl and it would be a shame to de-commission it. I was looking for a new cowl to do a refurb with electric retracts and a new engine.

The is the original H9 cowl, but would be happy with a 60 size replica I could paint.

Thanks for your help.

cowl.jpg

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Like Doug's, my H9 P47 cowl is knackered although the rest of the airframe is still nice and tidy after many years of flying - one of the best and most comfortable to fly scale models I've had in fact. I'm sure I contacted Vortex about their P47 cowl and they sent me dimensions which IIRC were a bit too small. Haven't had any luck elsewhere. Might have to refurb the original.

BTW Doug, I've had a pair of HK servoless retracts in my P47 for ages that replaced the hopeless mechanical ones supplied - been very reliable.

Edited By Cuban8 on 26/08/2020 10:57:02

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When ever I get afresh plane with a preformed cowl I tend , dependant upon shape, to make a cast out of cheap plaster . and then do the "pop bottle " shrink if I need a replacement , And now with the big 3 ltr bottles and the gallon water bottles , usually ribbed unfortunately , you can replicate the whole or part.

cheers

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You can usually patch up a poor cowl or make a blank. Both involve patience and much sanding. I'm working on my Sebart Angel 50 cowl at present which was very cracked. Most of these commercial ones are a bit thin and the flexing cracks the gell coat. Beefing them up internally when new helps.

I am planning to make moulds for the Hangar 9 Hellcat and P47 (the older 67 inch wingspan size for 60 I.c.) as these are not easy to obtain or are stupidly expensive or both! Watch this space or PM me for details.

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I cast the inside of my cowls , Just fill the new one with plaster , but support the new one in a bucket of sand so as the shape is not distorted,

When you "shrink" a bottle onto the plastercast , leave the screw on top in place because I find that putting a little hole in the cap and using a foot pump / airline you can blow the bottle off the mould .Providing there is no reverse angles inhibiting the release .

If there is no way of Blowing it off , I have resorted to cutting a straight line down the bottom of the Moulded cowl and peeling it and glueing up the cut

Outside moulds I make in two halves , ie Acrowot ones and then lay up fibreglass , messy but fun especially when it works , ,

dont "paint" the plaster casts in anything , In my case it always sticks to the inside of the cowl wrecking both cowl and mould ,

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  • 4 weeks later...

Phil,

This is starting to look like the process I followed with the cowl of a DSM Joker. The original was a sorry 2 part ABS vac form. I joined the two halves which had inevitably fallen apart, glassed the entire inside filling all the holes previously cut for the cylinder head etc. I made an MDF plug which fitted into the opening to prevent it from sagging. I then filled all the dents and scratches with car body filler, sanded and primed it. I made a moulding box which I filled with 2 part silicone moulding compound around the plug open side up. It took 2 attempts, the second one worked perfectly. With the mould still in the box for support, I layered the inside with 81gsm glass cloth and laminating epoxy SP113. Then a second layer of 180gsm cloth. I did this in strips and reinforced the stressed areas with extra cloth each time rolling it to the mould surface with a DIY long handled roller. On releasing the completed cowl from the mould the first few attempts weren't great but eventually this is what I achieved. cowl.jpg

Andy.

Edited By Andy Stephenson on 21/09/2020 23:03:22

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Thanks Andy and a good result. It's satisfying to make your own especially when the bought ones are so flimsy.

I intend to use 2 part silicone with some other material supporting and I may make a secondary plug to refine the shape a little.

Here is the moulding frame under construction.

img_20200921_212856.jpg

And the engine plate being prepared for moulding

img_20200921_215002.jpg

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Phil,

If you are still intending making your own cowl using silicone as the female mould, you don't need to make it in 2 parts as it looks as if you are. Silicone is flexible enough to get a single part out of the mould. That way there are no split lines to worry about.

The mould box originally had a bottom when the silicone was poured but it was removed to aid release of the cowl once it had hardened.

One important thing when pouring the silicone is that you must make sure the plug doesn't move as it will try to float being lighter than the silicone.

jokercowl.jpgimg_20200922_095022652.jpgimg_20200922_095042645.jpgimg_20200922_095110137.jpgimg_20200922_095130614.jpg

img_20200922_100931022.jpg

img_20200922_100915864.jpgimg_20200922_100857367.jpg

Edited By Andy Stephenson on 22/09/2020 10:17:06

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