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SF33 1/6 scale
Posted: 13 Oct 2018, 14:27
by Peter Balcombe
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.
Re: SF33 1/6 scale
Posted: 14 Oct 2018, 18:25
by FrankS
This looks a handy size, looking forward to following the build.
Re: SF33 1/6 scale
Posted: 14 Oct 2018, 21:38
by Peter Balcombe
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
Re: SF33 1/6 scale
Posted: 14 Oct 2018, 22:04
by chris williams
Here's Cliff with the prototype at the old Lords Hill Club back in 2002...
Re: SF33 1/6 scale
Posted: 15 Oct 2018, 14:34
by B Sharp
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.
Re: SF33 1/6 scale
Posted: 15 Oct 2018, 16:08
by Peter Balcombe
Very nice indeed Brian
![๐](//cdn.jsdelivr.net/gh/twitter/twemoji@latest/assets/svg/1f600.svg)
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
Re: SF33 1/6 scale
Posted: 15 Oct 2018, 18:58
by B Sharp
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.
Re: SF33 1/6 scale
Posted: 15 Oct 2018, 19:54
by Peter Balcombe
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 donโt expect a hatch to detract from the strength very much as the top is only 1/16โ 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.
Re: SF33 1/6 scale
Posted: 16 Oct 2018, 18:05
by Peter Balcombe
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.
![Fuselage_bot_sheeted.jpg (102.16 KiB) Viewed 11357 times Bottom sheeting](./download/file.php?id=13698&t=1&sid=5a23465ed7cb0abe63b41f2f9e8c7093)
- Bottom sheeting
![Fuse_rear_stringers.jpg (109.84 KiB) Viewed 11357 times Top formers](./download/file.php?id=13699&t=1&sid=5a23465ed7cb0abe63b41f2f9e8c7093)
- Top formers
Re: SF33 1/6 scale
Posted: 28 Oct 2018, 09:33
by Peter Balcombe
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.
![Fuz_tubes.jpeg (159.56 KiB) Viewed 11100 times Servo tray and rear tubes](./download/file.php?id=13782&t=1&sid=5a23465ed7cb0abe63b41f2f9e8c7093)
- Servo tray and rear tubes
![Battery_servo_trays.jpeg (89.66 KiB) Viewed 11100 times Battery tray](./download/file.php?id=13784&t=1&sid=5a23465ed7cb0abe63b41f2f9e8c7093)
- Battery tray