Semi-scale ASH25

[Jolly Roger]

Now the fun bit... excavating the foam.

It went brilliantly, coming out so cleanly without any messy solvents. Waxing the tape probably helped.

I was really glad I had a strong cockpit edge to work against with my chisel. A thin glass edge would have been very vulnerable.

Surprising how much weight there is in the foam...it dropped from 500g to 400g when foam removed.

In terms of rigidity, it is rock solid around the cockpit edge thanks to the carbon, but about as squishy as an orange squash bottle on the skin itself. So next step is to lay up 200gsm Diolen internally.

[Jolly Roger]

Diolen in. I used a cloth template to get a good fit.

When it’s cured I’ll see if it’s still squishy and add another layer if needed.

[Jolly Roger]

In the end I added 2 layers of 200gsm Diolen, which added to 3 layers of 200gsm glass brings it to a total of 5 layers and 1000gsm wall thickness.

It feels very strong and possibly too stiff. I think a fuselage needs a little flex in it to absorb landings (unconvinced? Watch me land). I also noticed it’s way harder to achieve a 1:1 resin to cloth weight ratio when working inside the fuselage rather than outside it. Pulling cloth around convex curves it’s much easier to wet out than pushing it into concave ones. My last layer of Diolen inside took 2:1 resin to cloth. The fus is still fairly light though.

I’m happy that the main glasswork is done now on the front fuselage, so this afternoon was just skimming the joins to the rear fuselage and wings with filler.

I had some spare epoxy so moulded a tray for the Lipo too from scraps of Diolen.

Not sure what next. Probably make the canopy frame.

[Jolly Roger]

So...the plan was to spend half an hour or so rubbing down the filler to get a decent blend between the wings and fuselage parts. Then the OCD kicked in. 3 hours later I’m satisfied with the finish.

To reward myself, I decided to make the canopy frame. Now remember that carbon ridge around the cockpit edge? Well this is where we have to mould an n-shaped canopy frame to fit over it.

First off, loosely cover the fuselage with a couple of layers of cling film.

Plan A was to lay a few strips of 200gsm glass cloth over the ridge, then squish down with foam and a hardboard template, to make the cloth conform to the cockpit ridge.

[Jolly Roger]

Whenever you call something plan A, it’s instantly doomed, isn’t it.

Well the foam didn’t work because no matter how hard I compressed it down onto the cockpit rim, it would not squeeze tightly into the corner.

Plan B... Abandon foam. Roll modelling clay sausages and push these over the glass cloth before clamping on the hardboard template. Seemed worth a try.

[Jolly Roger]

Strips of cloth applied, roughly 3 layers. A nice chance to use up a bunch of off cuts (well I do live inYorkshire.)

Then a layer of cling film, then the modelling clay, carefully nipped around the cockpit ridge.

[Jolly Roger]

Finally, hardboard template clamped in place, then off to my solar-powered thermo-cure system i.e. on the bench in the sun.

I’ll check it this evening before it fully sets then run some carbon tows around the outside for added rigidity. Not sure how to thicken up the frame edge to give gluing area for the canopy. May use 1/8” balsa. Ah yes, I remember balsa....

[Chris Bowles]

Hi Rog, at least you have some decent clamps to hand, always like a plan B
Chris

[Jolly Roger]

Well that went REALLY well. Just peeled off most of the modelling clay to reveal a light, snug-fitting canopy frame. Needs a tidy up, then I’ll run some carbon tows around it to stiffen and thicken up the edge.

Never mind the canopy frame. Why do I have a chunk of smashed foam glider in the background?

For many years a good friend from Holland has come over and holidayed in our village. He flies mostly small electric foamies but I’ve tempted him into slope soaring. Last August he brought the model in the photo and asked if i could get it to fly. We chucked it off the cliff above our house into a fresh and lifty breeze. It took me seconds to realise it was a total pig, flying very fast but with sluggish responses in every axis and the worst stall of any object I have ever steered with thumbs. I fought it for 2 minutes until eventually it ignored all controls and dived downwards to a place I had only ever been to in my darkest nightmares - the impenetrable and precipitous wood at the base of the cliff. I’m amazed really that I’ve flown here for 20 years and never once crashed a model into this most inaccessible of places.

Skirting around the top of the cliff, we glimpsed the model lodged in a tree about 400ft below. There is no way down, so we spent a few hours trying to climb up from below, returning with only grazed knees and hands torn by brambles. I waited until the leave-fall of Autumn and tried again, but was defeated again by the nearly vertical slippy bank side.

Fast forward to this afternoon and a neighbour passed the model over the hedge by my workshop. He’d been exploring the caves in the cliff and had stumbled upon these sad looking remnants. His son, (half Olympic gymnast, half goat) had somehow managed to reach it.

So, that’s about as happy an ending as I could hope for.

I have, let me see....NO intention of fixing it, but am happy that it is no longer littering the hillside.

[B Sharp]

Goodness, what an exciting life you lead Rog!
Brian.