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1/4 Scale ASK21**
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: 1/4 Scale ASK21
Hi Mike,
I used an epoxy compatible polyester gel coat (Easy Composites GC50), then a 100gsm layer from nose to wing root, plus 2 layers of 300gsm (one twill? & one plain weave) using 5 main pattern shapes per side.
In addition, I used 300gsm blisters in the wing root, main wheel & tailwheel fairings, plus strips/rovings around all of the canopy flanges.
The layup was as recommended by John Hall who has made all the fuselages for the Pat Teakle range over the years.
1/4” ply wing roots have now been epoxied into the insides of the wing roots & glassed over.
My only issues were where the mould surface wasn’t perfect (primarily around the wing root/canopy flanges) & my layup also had a couple of voids behind the gel coat in similar areas.
However, as I didn’t have a pigment in the gel coat (GC50 is clear only) then it isn’t really a problem as I have to paint the part in any case, so this will also cover the small amount of filling needed.
Peter
I used an epoxy compatible polyester gel coat (Easy Composites GC50), then a 100gsm layer from nose to wing root, plus 2 layers of 300gsm (one twill? & one plain weave) using 5 main pattern shapes per side.
In addition, I used 300gsm blisters in the wing root, main wheel & tailwheel fairings, plus strips/rovings around all of the canopy flanges.
The layup was as recommended by John Hall who has made all the fuselages for the Pat Teakle range over the years.
1/4” ply wing roots have now been epoxied into the insides of the wing roots & glassed over.
My only issues were where the mould surface wasn’t perfect (primarily around the wing root/canopy flanges) & my layup also had a couple of voids behind the gel coat in similar areas.
However, as I didn’t have a pigment in the gel coat (GC50 is clear only) then it isn’t really a problem as I have to paint the part in any case, so this will also cover the small amount of filling needed.
Peter
- Mike Forsyth
- Posts: 3
- Joined: 14 Jun 2015, 09:30
Re: 1/4 Scale ASK21
Thanks for the information, it will come in very handy. One last question what was the weight of the fuselage? I always wanted to try making a glass fibre fuselage, but I think I will try on a smaller model first, just to test the water so too speak, I don't think I'm brave enough to do a 1/4 scale model, Even though you have a few imperfections you have done a remarkable job on your very first glass fibre fuselage I can only hope I'm that lucky.
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: 1/4 Scale ASK21
Mike,
Bare fuselage weight with ply root blanks fitted is 1.7Kg for a fairly bulbous 2m long fuselage. (Wing is 70mm thick at root).
Not sure if this is heavy or not, although I gather that epoxy resin fuselages are usually lighter than polyester resin ones, but this obviously depends on the quantity of cloth & resin used in each case.
Bare fuselage weight with ply root blanks fitted is 1.7Kg for a fairly bulbous 2m long fuselage. (Wing is 70mm thick at root).
Not sure if this is heavy or not, although I gather that epoxy resin fuselages are usually lighter than polyester resin ones, but this obviously depends on the quantity of cloth & resin used in each case.
- Simon WS
- Posts: 205
- Joined: 18 Mar 2015, 11:39
- Location: Kent, UK
Re: 1/4 Scale ASK21
Fantastic achievement Peter.
Simon
Simon
Re: 1/4 Scale ASK21
Well done Peter, will you be challenging Roo for fastest build?
- Mike Forsyth
- Posts: 3
- Joined: 14 Jun 2015, 09:30
Re: 1/4 Scale ASK21
Thanks, Peter. 1.7kg for the fuselage is not too bad, I will be watching this with special interest. You have done a Fantastic job
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: 1/4 Scale ASK21
Geoff,
I don’t think Roo has anything to worry about
It’s taken 18 months so far to just get a fuselage.
However, wing & tail designs are done, so maybe have something to maiden by next Spring.
I don’t think Roo has anything to worry about
It’s taken 18 months so far to just get a fuselage.
However, wing & tail designs are done, so maybe have something to maiden by next Spring.
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: 1/4 Scale ASK21
Cliff Evans kindly cut some parts for me, so the tailplane has started taking shape as shown below.
The plan is to embed a thin wing servo in the rear of the tailplane, this driving the elevator via a short pushrod to a ball joint on the bottom of the central elevator half joiner. The linkage sits in a slot cut in the top of the fin.
The tailplane is attached using a single bolt and anti rotation pin.
Last edited by Anonymous on 14 Sep 2018, 09:01, edited 1 time in total.
- Simon WS
- Posts: 205
- Joined: 18 Mar 2015, 11:39
- Location: Kent, UK
Re: 1/4 Scale ASK21
Looks very neat Peter
Simon
Simon
- Peter Balcombe
- Posts: 1399
- Joined: 18 Mar 2015, 10:13
- Location: Clevedon, North Somerset, U.K.
Re: 1/4 Scale ASK21
Everything looks good, so the lower building tabs have now been removed and lower spars fitted ready for application of the lower sheeting.
Note that tip blocks have still to be added to give the final shape.
I will investigate fitting of a servo hatch to allow access, plus fitting the tailplane to the top of the fin.
Rudder construction has also started, so I hope to be able to check the overall fit of the tail feathers soon.