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SF33 1/6 scale

Fans and Thermals.
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Peter Balcombe
Posts: 666
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

SF33 1/6 scale

Post by Peter Balcombe » 13 Oct 2018, 14:27

I have just started building a 2.5m version of the SF33 motor glider from the Cliff Charlesworth plan using a short kit of parts provided by Cliff Evans as usual.
Starting with the fuselage, this is built from two 1/16" balsa sides and a few sticks of 1/8 sq. balsa.
I built mine upside down, using the straight upper fuselage rail as a reference.
The difficult bit is to get the sides stuck to the formers without introducing a banana curve along the centreline.

The fuselage bottom will be covered with cross grain 1/16" balsa, except for the nose area which uses thicker balsa sheet, sanded to profile later.
Attachments
SF33 Top_small.jpg
SF33 Bottom_small.jpg

FrankS
Posts: 231
Joined: 18 Mar 2015, 14:29
Location: Gloucestershire

Re: SF33 1/6 scale

Post by FrankS » 14 Oct 2018, 18:25

This looks a handy size, looking forward to following the build.

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Peter Balcombe
Posts: 666
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SF33 1/6 scale

Post by Peter Balcombe » 14 Oct 2018, 21:38

Frank,
To further whet your appetite, you may be interested in the following link to a thread covering the build of the same model on another modelling forum.
There are some pictures of the almost complete model plus a flying shot further down.
http://www.gliderireland.net/forum/inde ... pic=3274.0

Peter

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chris williams
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Joined: 10 Mar 2015, 10:50
Location: Blandford Dorset

Re: SF33 1/6 scale

Post by chris williams » 14 Oct 2018, 22:04

Here's Cliff with the prototype at the old Lords Hill Club back in 2002...
Attachments
06010001 copy.jpg

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B Sharp
Posts: 456
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: SF33 1/6 scale

Post by B Sharp » 15 Oct 2018, 14:34

Peter, here are a couple of pictures of my version, which flew very successfully for many years. The airframe still resides in my attic and could be revived with the addition of radio and a motor.
Brian. :D
Attachments
SF33_001.jpg
SF33_002.jpg
SF33_003.jpg

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Peter Balcombe
Posts: 666
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SF33 1/6 scale

Post by Peter Balcombe » 15 Oct 2018, 16:08

Very nice indeed Brian 😀
I will need to have a chat about the arrangement for fixing the motor/clearing the forward former on the motor hatch.
The plan appears to show the top of the front bulkhead as a separate piece above the motor centre-line, but I wonder if that is intended to just be the cut line marking a separate part former (1A) to be used as the basis for the forward part of the top hatch (with much of the former removed to clear the motor.)
Can you recall if your motor bulkhead was fitted as top & bottom, or a single full height motor bulkhead, with duplicate top part for the hatch front?
Peter

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B Sharp
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Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: SF33 1/6 scale

Post by B Sharp » 15 Oct 2018, 18:58

Peter, I also was a bit confused with the front end. I used a Tornado BM600kv 1000 motor from Overlander with a Jeti Spin 44 esc. this was bolted to one solid former. Rather than a weakening hatch I built the front coming as solid. Interestingly I used a variable pitch setting prop from Steve Mettan at " Modelhaus" which allowed me to alter the pitch without changing the diameter.
Brian.

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SF33 1/6 scale

Post by Peter Balcombe » 15 Oct 2018, 19:54

Thanks for info Brian.
As I had already put in the supplied part-height (up to motor centre) front bulkhead (which allowed the fuselage to be built upside down over a plan view on a flat board, my plan is to now to epoxy the top part of the bulkhead on, but then fit a full bulkhead as a doubler.
I don’t expect a hatch to detract from the strength very much as the top is only 1/16” balsa sheet anyway.
The benefit is that it will allow easy access to the motor & ESC.
I have an old Dualsky XM3548CA-4 1080kv outrunner motor plus matching ESC which should provide ample power & run off a 3S LiPo.

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SF33 1/6 scale

Post by Peter Balcombe » 16 Oct 2018, 18:05

A bit more progress, including completion of sheeting & wheel attachment on the bottom (still needs shaping), addition of some of the upper fuselage formers and also the front bulkhead doubler after drilling the motor fixing holes.
Attachments
Fuselage_bot_sheeted.jpg
Bottom sheeting
Fuse_rear_stringers.jpg
Top formers

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SF33 1/6 scale

Post by Peter Balcombe » 28 Oct 2018, 09:33

The liteply battery mounting plate, servo tray and tail surface bowden tubes have now been fitted to the fuselage.
Next job is to prepare the top turtle deck skin and set the curvature ready for fixing in place, probably using the ammonia technique.
Attachments
Fuz_tubes.jpeg
Servo tray and rear tubes
Battery_servo_trays.jpeg
Battery tray

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