Windscreen for 1/4 scale Piper Cub

[Malc. Nicklin]

Hi from Perth Australia,

 

I have been given a 25 year Piper Cub model ( kit manufacturer unknown) and I have re built the old lady so far to the point of the windscreen.

 

I have the old screen which I could use as a template but I need help in curving those nice bits around the leading edges of the wings.

 

should I make a mould and vacuum the sheet to profile and this is where I need help please.

 

Malc.....

 

 

 

 

 

[Martin Harris - Moderator]

Malc,

 

I've just made a screen for a 1/4 scale Cub that I acquired partly completed but with some bits missing and some very "odd" styling around the cockpit area which necessitated making a new screen after returning the area to resemble that which Messers Taylor and Jamouneau designed.

 

I used clear "Plasticard" 20 thou (that's 0.5 mm to you) thick which I've just discovered is Polyethyleneterephthalate Glycol Sheet (PETG).

 

The Cub screen seems to be cunningly designed to not have any double curvatures and will bend from flat sheet.  I did it cold but have since read that it softens at 80 degrees C.  I have noticed some fine internal stress fractures which are visible in certain light so I may need to do the job again (with heat) sometime in the future if they cause cracks to appear.

 

With the luxury of a template you should be laughing but I made a basic template from a sheet of A4 paper, gradually developing the shape in situ , then cut the glazing slightly oversize in the wing root area and trimmed it gradually with curved "plastics" scissors to follow the leading edge profile as closely as possible.

Edited By Martin Harris on 27/08/2010 14:16:00

[Malc. Nicklin]

Hi Martin,

 

Thank for the response and the ideas and I think we will call the Plasticard just that  or (PETG) never mind the full handle. Now I have look at a lot of Cub Photos and model photos of same and mine is a bit of an odd ball.

 

The kit was produced in Japan around 30 years ago so I'm lead to believe by a company called Jet ( only just found that out this morning)  but are no longer around.

 

Now I say mine is a odd ball the top of the screen near the wing leading edge is curved there  as the norm and then curved again to meet the the former which will be F2 then back out again to the other side.  If I may be so bold it looks like a BRA ......the bumps go over the leading edges both sides of the screen.

 

I have not seen this profile on any of the photos of the normal Piper Cub so I'm thinking was it a mistake they made all those years ago when producing the kit?

 

Now then the sheet where did you pick it up from,  is it used  in the stationary business and what sizes does it come in ?

 

Thanks again for your help and I may just try the flat sheet and the flame thrower trick.

 

Many thanks mate .

 

Malc.....

 

 

 

[Martin Harris - Moderator]

I got mine from a model shop but I'd imagine any craft shop would stock it for such things as dolls house windows.

 

Mine's made by Bayer in Germany - but there's a division in Australia see - they don't list the 0.5 mm sheet and the sheet size would be good for glazing a full size Cub but it does say enquire for other gauges and sheet sizes. They might also be able to supply a "sample" or put you on to a retailer.

 

You'd need to experiment but I'd imagine soaking it in close to boiling water might soften it for easy bending although you'd need to be quick as I wouldn't think there's much heat retention.  Otherwise a heat gun carefully applied might do the job.

Edited By Martin Harris on 28/08/2010 12:39:25

[Malc. Nicklin]

Again thank you Martin I'll try and get some and give it a go and let you know how I go on,

 

I used the heat gun on some of the other screens I have done but this one is odd ball for sure and I may just use the flat sheet without too much bending and not bother with these bumps and just fold it around the top part and down the sides and then trim it up.

 

I can't understand why they went to all that trouble to put those two bumps in it instead of the normal Cub screen.

 

Many thank again I'll try and get some in the week as it's Saturday night here in OZ and time for bed .

 

Catch ya later .

 

Malc.