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Semi-scale ASH25

Jolly Roger
Posts: 514
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Semi-scale ASH25

Post by Jolly Roger »

So instead I’m going to laminate the glass skin directly onto a blue foam core. No fancy vacuum bagging, in fact I didn’t even hotwire the core - I’m just cutting one side from a block, then glassing it, then cutting the other and glassing it.

The idea is to get a strong, glass-looking rudder with a quick low-tech approach.

Here’s the core with one side cut away, then sanded smooth.
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Jolly Roger
Posts: 514
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Semi-scale ASH25

Post by Jolly Roger »

Here it is stuck with double sided tape to a flat board (I noticed it warped slightly when cut/sanded). Two 100gsm cloth skins prepared, weave at 45 deg.
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Jolly Roger
Posts: 514
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Semi-scale ASH25

Post by Jolly Roger »

And here it is 5 mins later after cloth applied with resin.

I find it takes about 1.2 : 1 resin to cloth (by weight) when applying to highly absorbent surfaces like foam.

Since deciding to go with a foam core I’ve spent just over an hour on it to this point.
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Jolly Roger
Posts: 514
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Semi-scale ASH25

Post by Jolly Roger »

I skinned the second side of the rudder yesterday and today sanded it to a smooth finish using 240 grit (wet).

I am chuffed to bits with the finished result. It has a rock hard, smooth skin, sharp, tough and straight trailing edge, it will not bend or twist, and it weighs just a few grams more than the old wooden rudder. Best of all, it took just an hour and a half to make. What IS happening? Nothing I build ever goes that quickly!

Will definitely be using this method again for fins, rudders and tailplanes. May reduce the 2 layers of 100gsm to 1 x 100gsm + 1 x 50gsm because this rudder is needlessly strong.
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Jolly Roger
Posts: 514
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Semi-scale ASH25

Post by Jolly Roger »

A quick update on this model. With its new front fuselage pod and canopy and now an entirely new rear boom and tail unit, this model (like Trigger’s broom!) doesn’t have much to do with an ASH25 any more. Maybe more JS3 Rapture?
Anyway, after its re-maiden at the Eden Valley event a couple of weeks back, I flew it for 2 hours this evening tweaking the CG and surface trims and am now delighted with how it handles.
All that remains is to crash test it…which I’ll no doubt do in due course 🤣
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