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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. :D

Re: SF33 1/6 scale

Posted: 15 Oct 2018, 16:08
by Peter Balcombe
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

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 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.

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.

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.

Re: SF33 1/6 scale

Posted: 03 Nov 2018, 10:56
by Peter Balcombe
Now with the rear turtle deck fitted & ready to move on to fitting the forward part.

Re: SF33 1/6 scale

Posted: 05 Nov 2018, 16:41
by Peter Balcombe
Tailplane & rudder framework made up from 1/4" sq balsa, with additional 1/4" sheet infill as necessary.
It is only possible to make up the fin framework once these parts are clear of the board as the tailplane drawing overlaps the fin structure!

Re: SF33 1/6 scale

Posted: 12 Nov 2018, 18:58
by Peter Balcombe
Tail feathers now built and ready to add the control horns/make the upper/rear fuselage fairing.

Re: SF33 1/6 scale

Posted: 19 Nov 2018, 15:03
by Peter Balcombe
At the front end, the fuselage top has been skinned after making a simple framework for a removeable cowl.
Both sides of the cowl /fuselage interface were protected with a gloss masking tape to aid later removal & the joint line maked on the fusealge to aid placement of a scalpel blade to run around the joint later.
Everything went to plan & the cowl was easily removed once the glue had set.
The photos below show the cowl fitting ok with the motor in place.
The internal cowl framework can be seen on the 2nd pic.

Re: SF33 1/6 scale

Posted: 24 Nov 2018, 19:06
by Peter Balcombe
Canopy frame built from Liteply, with solid front & rear plus side rails to leave a space in the middle for a drop-in unit to be added for cockpit detail.
Attachment is a peg at front and a registration lip + small magnet at the rear.

Re: SF33 1/6 scale

Posted: 29 Nov 2018, 20:34
by Peter Balcombe
Moving on to the first wing, this is built up on the bottom spar with outer TE packed up to give 5mm washout over the aileron length.
The plan shows the 5mm TE glued directly to the rear of each rib, but I added a 6mm wide strip of 1/16" balsa sheet under the rear of each rib (same thickness as balsa skin/cap strips to be added later) and then added further 1/16" balsa strips between each rib. Once a further 6mm wide strip is added to the top, this will give a more solid edge to secure the TE.
The top spar, joiner tubes, angled root sub-spar and balsa dummy LE have also been fitted, plus upper aileron hinge spars, so this panel is nearly ready to have the top skin fitted.
Most of the internal details (servos, joiner tube area webbing, main spar webbing etc. will be fitted once the top skin is in place.

Re: SF33 1/6 scale

Posted: 07 Dec 2018, 15:28
by Peter Balcombe
A bit more progress over the last couple of weeks in that the top D box skin and most of the spar webbing is in place, together with the upper aileron spars & top skin.
A note here that although the plan calls for 3mm square balsa aileron spars, I have only fitted the upper ones so far as the notches need to be cut in situ as the plan doesn't show any slots on the rib templates. I also decided that as the top spars left little 'meat' on the ribs, I would leave the lower spar slots until the aileron area had top skin support.
Also, with the upper 1/16 balsa strip fitted across the rear of the rib, the 15mm wide TE strips could be added (inboard & outboard of the aileron break).
The remaining spar webbing has now been added, so the remaining upper skins can be added at the root end and the TE strips profiled to section.
The aileron & spoiler servo cables need to be added before the route is covered up by the lower D box skin.

Re: SF33 1/6 scale

Posted: 13 Dec 2018, 12:19
by Peter Balcombe
With the 15mm wide TE strip added, spar webbing complete (including the angled spars), the upper root end skins have been fitted.
Next jobs are to fit the spoiler arrangement and servos prior to adding the lower D box skin.

Re: SF33 1/6 scale

Posted: 14 Dec 2018, 01:56
by Tonyw51
G'day Peter,
I have just today received my e plans and laser cutting e plan for this model. It is my first attempt at a scale model and I am finding your Build Log very helpful. I have sent off the cutting plans for a quote and hope I will be able to start the build early in the new year.

Looking forward to your continuing Log.

Cheers,

TonyW51
Melbourne, Aust.

Re: SF33 1/6 scale

Posted: 14 Dec 2018, 07:32
by Peter Balcombe
Hi Tony.
Very glad to have you on board.
The plan is probably not one of Cliffs best (God rest his soul), but I can help fill in missing info./telling you what I have done.
It does appear to turn out to make up a very nice looking model which appears to fly well.
The photos below are from an Irish build thread.

Re: SF33 1/6 scale

Posted: 14 Dec 2018, 21:34
by Tonyw51
Cheers Cliff. I'm onto that today.

Thanks and regards
Tony

Re: SF33 1/6 scale

Posted: 14 Dec 2018, 21:38
by Tonyw51
Thanks Peter, I must say that it was the Irish posting that sparked my initial interest in this model.

I look forward to asking for your assistance in the not too distant future.

Thanks and regards,

Tony

Re: SF33 1/6 scale

Posted: 27 Dec 2018, 13:54
by Chris V
Hi there, I am really interested in building this lovely little motor glider

What electric set up is everybody going to use ie which motor and what power set up 3s or 4s lipo ???

Thanks Chris

Re: SF33 1/6 scale

Posted: 27 Dec 2018, 16:15
by Peter Balcombe
I have an old Dualsky XM3548CA-4 1080kv motor plus Dualsky XC4118BA 40A ESC which is expected to be used with a 9x6 or 10x6 folding prop.
Battery will be 2 or 3S to suit power required (I cannot remember at the moment what the Irish model setup was).

Re: SF33 1/6 scale

Posted: 09 Jan 2019, 02:39
by Tonyw51
G'day Peter & Chris,
Much excitement in the workshop today with the arrival of my short kit from SC Models. So now have the plans printed, mirrored and printed again (and they are a perfect match), the short kit and the canopy "in the mail" from Sarick. I am in the process of completing a Brolga (2.0 mtr. Australian model) and as soon as it has had its maiden flight I shall start on the SF-33.

I am very happy with the quality of laser cutting and I shall start to rifle though the stores of strip and sheet to put together a complete kit, so all is looking good

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 15:33
by Peter Balcombe
Spoiler now added together with servo & operation checked.
(Will need to be top wing surface hinged using film or tape in due course)

Aileron servo position added.

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 17:21
by StephenB
Very neat job on the spoiler installation Peter with the servo nicely hidden by the sheeting.

Having never done it before(always used commercial brakes), but about to tackle this job, how have you secured the servo and is the pushrod connection a z bend at both ends? Have you mde the spoiler from 1/16" sheet with ply reinforcement? The way you have done it looks a lot simpler than some methods I have seen which often employ a 6mm sq. balsa framework and a more complicated linkage arrangement.

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 20:31
by Peter Balcombe
Stephen,
Servo body located in a slot in an extra 2mm Liteply sub-rib, with servo mounting lugs trapped behind balsa spaced off rib by thickness of lug. A touch of hot glue will firmly secure in place before bottom sheeting added later.
Yes, thin wire pushrod with Z bend each end. Needs to be exact length, but cannot come loose later when under sheeting.
Spoiler is 1/16” balsa with thin ply backing & 1/16” epoxy board horn glued in.

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 21:41
by chris williams
Er, what will you do if the servo fails later on, Peter?

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 22:05
by Peter Balcombe
Chris,
Could make a small balsa framed hatch on underside with 1/16” sheet balsa cover taped in place if need be, else cut out a small area of lower skin and make good if and when a fault occurs.
Similar issue with aileron servo as the 1/6 scale wings aren’t very thick. However this servo will be in an open structure area, so covering can be cut away locally and a patch put over when done.
Peter

Re: SF33 1/6 scale

Posted: 12 Jan 2019, 22:36
by B Sharp
Don't worry too much about the servo failing Peter. I have buried servos in numerous models over the years and I can remember only one failing. I tend to use the best and most reliable servos that I can afford . I have models with buried servos on airbrakes, rudders and on the elevator of my Dart. Seven or so years on they still operate without a problem.
Brian. :)

Re: SF33 1/6 scale

Posted: 13 Jan 2019, 00:33
by chris williams
Looks like Brian's got immunity from Murphy's Law... :D

Also...7 years? That's still brand new!

Re: SF33 1/6 scale

Posted: 13 Jan 2019, 08:24
by Trevor
Like Brian, I usually just bury wing servos. I rationalise my laziness by the argument that if you do have to cut your way in to replace one, the resulting patch is normally no more visible than a hatch would have been anyway, so why disfigure the aircraft with all those hatches beforehand? It does pay to take a few photos of the installation before covering it up though, so you can work out where to make the incision when the servo fails 20 years later!

Whichever way you do it, Murphy's law dictates that the servo will be out of production by the time it fails so you'll probably have to replace two of them and hack the mounting about - hatch or no hatch.

Re: SF33 1/6 scale

Posted: 13 Jan 2019, 20:28
by Noël Rumers
Hi,
I do the same, never had a problem...
I know Murphy too!
But I know where to cut and that is ifffiiiiffff....
Noël

Re: SF33 1/6 scale

Posted: 13 Jan 2019, 20:43
by Peter Balcombe
There you go then.
I think I will definitely go for the buried servos & smooth finish option, keeping a sharp scalpel handy in case of a problem.

Re: SF33 1/6 scale

Posted: 18 Jan 2019, 16:44
by Peter Balcombe
Lower sheeting now in place - with spoiler servo buried!
Balsa LE strip has since been fitted together with aileron hinge area sheet.
Next job will be to complete sanding of the sheeting around the aileron before cutting this free.

Re: SF33 1/6 scale

Posted: 16 Apr 2019, 11:57
by Tonyw51
G'day Peter,

How is the build going?

Cheers,
Tony

Re: SF33 1/6 scale

Posted: 16 Apr 2019, 12:14
by Peter Balcombe
No more progress yet I’m afraid as I have been diverted by the SG38 , PIK20 rebuild and other projects.
Hope to get back onto it soon though.

Re: SF33 1/6 scale

Posted: 18 Apr 2019, 14:11
by Tonyw51
Yes I know the problem, I have just started building a bass guitar for my son which is receiving the attention and enthusiastic priority of my wife. I think modeling is on the back burner for a couple of weeks

Re: SF33 1/6 scale

Posted: 20 May 2019, 10:50
by Peter Balcombe
Just got back to the SF33 build, so have started on the LH wing.
The build is pretty much as for the 1st wing & I am currently notching the ribs for the aileron spars.
Once the upper hinge spar spar glue has set, it will be time to cut notches for the top aileron LE spar.

Re: SF33 1/6 scale

Posted: 20 May 2019, 19:11
by Peter Balcombe
And now with both wings fitted to fuselage to epoxy the carbon main joiner tube in place.

Re: SF33 1/6 scale

Posted: 20 May 2019, 23:39
by Tonyw51
G'day Peter, Good to see you back on this project. Could I ask you to put in a feed of detailed photos on the wing construction. Thanks, Tony

Re: SF33 1/6 scale

Posted: 21 May 2019, 10:50
by Peter Balcombe
Hi Tony.
Please look at the earlier part of this thread for photos taken during the 1st wing build, but I will add a few more as I put the 2nd one together.

As mentioned before, this plan is hand drawn and suffers from several inconsistencies & what I consider to be missing build info.
Thus it is not a good 'first build' model, but looks as if it can be made into a nice model with a little care and ingenuity.

As stated previously, I started my wing construction y laying down a pre-spliced lower main spar over the plan, spaced off the building board using 1/16" balsa spacers to simulate the bottom sheeting to be applied later. I also laid down a 1/4" wide strip of 1/16" balsa immediately forward of the TE section upon which to lay the rear of each rib.
Each rib can now be glued onto the main spar and TE strip after fettling to adjust the spar slot width and also the front edge to ensure a straight line at the front for fitting the dummy LE strip next. The most important ribs to get sorted out before assembly are the ply ones (R1 & R3), a these are harder to adjust in situ. I filled the spaces between each rib at the TE with balsa strip, sanded down flush with the tops of the ribs later.
Once a further 1/16" balsa strip is added, this gives a solid TE structure to fit the TE onto.

With all ribs in position (remember to angle the root rib & to fit a washout wedge under the TE from inner end of aileron), the dummy LE can be butt-jointed to each rib and then the 1/8" balsa root corner gussets added.

A length of 8mm ID carbon tube can now be inserted trough the holes in the root ribs & epoxied into position, followed by addition of the top spar (after fettling the rib slots to suit).

Now add the spruce top drag spar and the additional wedge behind the main spar over the joiner tube. The ribs are only cut for a wedge spar out to R4, but I took mine out to the drag spar intersection to give support for the webs to be fitted out to there. (I also added a cap to the joiner tube and filled the void between joiner tube & top/bottom spars/edges with hardwood/epoxy later, before the area was sealed with the webs).

There are no pre-cut notches for the aileron hinge & LE spars, this this has to be done manually. Bearing in mind the slimness of the ribs at this point, I decided to only fit the upper spars until the area had been sheeted in order to provide support whilst the lower notches were cut later. Hence i measured the spar locations & carefully notched & cut the ribs for the upper hinge spar only, fitted the spar & once secure, cut & fitted the 2 aileron end riblets, tack gluing these in place whilst spaced off the full ribs. Then the intermediate ribs can be very carefully notched and the top aileron LE spar fitted.

At this point, you are about ready to apply the upper sheeting once the dummy LE has been sanded flush to the top of the ribs & other areas prepared.
The rear incidence tube could be fitted before the top sheeting is added, but this can be easily done later before the lower sheeting is fitted. Holes are provide in the root ribs but when fitting, ensure that the incidence rod is parallel to a fitted main joiner in both front-rear & plan views.
The rear tubes could be also fitted using the fuselage as a iig as a single rod is used for each of the main joiner & rear incidence alignments.

A few detailed photos below may also be of use.

Re: SF33 1/6 scale

Posted: 23 May 2019, 10:04
by Tonyw51
G'day Peter,
Thank you for your post 21 May. You are so right with regards your comments about "first build". However, I am slowly muddling my way through and having a great deal of enjoyment in the process.

I really do appreciate your comments and instructions, they are a great help and confirm a great deal of what I have read into the plans, which is really comforting.

As a side, I was originally brought up using imperial measures, but when I started to play with European and Japanese motor bikes I built my workshop to metric and that was 40 years ago. Fortunately I still have fluency in "Imperial".

Cheers and thanks,

Tony.

Re: SF33 1/6 scale

Posted: 27 May 2019, 20:04
by Peter Balcombe
Tony, we have to be fluent in both Imperial & metric in the UK :?

Moving swiftly on ... Once the top D box skin has been put on (with washout wedge in place), the rear edge of the balsa sandwich at the back of the wing ribs can now be straightened as required to fit the balsa TE stock.
At the root end, I now add the underside drag spar and joiner area sub spars to match those on the topside.
The front spar webs can be put in place over the first few rib bays & then the wing stood on its dummy LE to epoxy spruce infill around the joiner tube & firmly bond the tube to the main spars.
Once that has been done, the remaining spar webs can be added, including those behind the drag spar.

With both wing structures available I have also installed the rear incidence joiner tube into the fuselage and the 2nd wing, temporarily setting everything up with the fuselage to make sure that everything lines up & will subsequently rig easily.
Note; As far as I can see, the forward wing retention hook has to be fitted further forward of that shown on the plan due to a significant cable access hole forward of the main joiner. Moving it forward between 6-10mm should work.

Re: SF33 1/6 scale

Posted: 27 May 2019, 22:29
by Peter Balcombe
Front hook centre has been placed 30mm behind front of dummy LE, so 36mm behind LE at the root (which puts the rear edge of the doubler at the forward edge of the laser cut cable hole). I used 1/2”x1/4” Spruce strip doublers glued to inside of the root rib at the attachment points & will probably screw in small hooks at these points for use with elastic bands or similar through the fuselage.
Note that the rear attachment is directly beneath my rudder/elevator servos, so the band will need to be fished through each time, or left attached to pegs each side to ease rigging :o

Re: SF33 1/6 scale

Posted: 28 May 2019, 08:01
by Tonyw51
Hi Peter,
Yes I can see the rear hook will be well covered by the servo tray. I have a PA-22 model that uses a grub screw through the wing spar tube and it seems to work quite well. Maybe the same could happen in the rear incidence tube. Something to consider, I also shall consider a peg/hook mounted on a the bulkhead.

Looking at the vertical stabiliser I am not sure of the mounting strength of gluing it to the 6mm plate in the fuse. What have you done there?

What type of hinges are you using for the control surfaces? I am considering the hinged Du-Bro.

Cheers,
Tony

Re: SF33 1/6 scale

Posted: 28 May 2019, 08:56
by Peter Balcombe
Tony,
Tail feathers are made but not yet attached until they have been covered.
I will almost certainly glue them on, making sure there is good clear contact between the wood on each side (covering overlaps removed as required).
(I have used this method on a 1/4 scale Mick Reeves Fournier RF4, so not a problem at 1/6 scale as long as you have wood/wood contact).

I have used Mylar strip hinges (approx 3/8” wide) on the tailplane & rudder (have previously also used this on up to 1/4 scale). I will also use this method on the ailerons to provide a basic hinge, using a full length Blenderm type tape gap seal.
I would have thought Du-bro hinges will be rather prominent & not really necessary for a smaller model of this type.

Re: SF33 1/6 scale

Posted: 05 Jun 2019, 03:09
by Tonyw51
Hi Peter,
Thanks for your comments, I just feel uncomfortable with the lack of bracing from the attach point through the butt joints. I have covered the the Fin and Horizontal Stabiliser with 0.5mm ply which has added very little weight but it has stiffened the parts and spread the loads. See attached

Image

I am happy with the Du-Bro hinges which have fitted quite well.

Looking forward to your updates.

Cheers,
Tony

Re: SF33 1/6 scale

Posted: 05 Jun 2019, 15:17
by Peter Balcombe
Just made up a couple of cowl cheeks.
Only a plan view of the cheeks showing internal hollowing out is shown on the plan, so have plumped for 1” height in side view with freehand curves. Balsa block is roughed out then sanded to give outer curves.

I will now Glass the cheeks to give some strength before hollowing out & fixing in place (centreline on the hatch edge!)
(The fuselage will also be glassed to provide a painting surface rather than try to apply film).

Re: SF33 1/6 scale

Posted: 19 Jun 2019, 21:29
by Peter Balcombe
The 2nd wing is now also about ready for covering although aileron horns still be made & fitted.
Meanwhile, I have applied 2 layers of lightweight glass cloth to the cowl cheeks, sanded smooth & then waxed prior to making a backup plaster mould before digging out the majority of the balsa from the resultant shells - just in case ;)
Once I have cut a nose aperture on each, the cheeks will be epoxied to the cowl hatch & then the relevant part of the hatch sides cut away to allow cooling air to be directed into the motor/ESC.

The fuselage has also been glassed & given an initial dust with primer to see how much further work is required prior to painting.

Re: SF33 1/6 scale

Posted: 22 Jun 2019, 13:38
by Peter Balcombe
With removable motor access hatch fixing sorted using pegs and magnets, the cowl cheeks were epoxied to the hatch so that they straddled the join line.
A liitle bit of joint reinforcement later, the cheeks can be used as finger holds whilst removing the hatch.
With the fuselage glassed & rubbed back, it's nearly ready for painting.

Re: SF33 1/6 scale

Posted: 03 Jul 2019, 13:03
by Peter Balcombe
Fuselage primed and then given a couple of coats of SigMarine gloss white, cockpit given a (short) pilot figure and canopy glued on with Canopy glue.
Tail feathers also covered using HK covering film (with slightly contrasting colours/paterns top & bottom to help with model orientation).

The wings have also had the aileron servo & spoiler installed prior to covering with the same HK heatshrink film.
The outrigger legs have also be fitted after drilling a locating hole in the spruce subspar at the inboard end & then removing a narrow strip of the balsa skin to accept the leg after covering. The outboard end of the legs are retained by small plates screwed into the hardwood sub-spar/main spar.

Re: SF33 1/6 scale

Posted: 03 Jul 2019, 18:39
by Peter Balcombe
With the tail feathers glued in place, its time for the first overall assembly.
Power train and wheels to fit, but nearly there now.

Re: SF33 1/6 scale

Posted: 05 Jul 2019, 11:54
by Tonyw51
G’day Peter
That’s looking good. I am interested in the glassing of the fuselage, what weight and cut did you use? I figure that is the way to go as the fuselage is very light in structure and a laminate of glass would be a very beneficial move

Cheers
Tony

Re: SF33 1/6 scale

Posted: 05 Jul 2019, 15:33
by Peter Balcombe
Hi Tony,
I used the standard 25gsm lightweight wing skinning variety, with just a single layer, essentially done as 2 sides with overlap along top & bottom centres.
Resin applied sparingly over the cloth with a brush, making sure that everything was fully wetted out.
Rubbed back before applying a dust coat of primer to help see & correct the worst imperfections (particularly around wing roots) before brushing on a couple of coats of Sigmarine white.

Re: SF33 1/6 scale

Posted: 09 Jul 2019, 23:04
by Peter Balcombe
Power train now installed.
I am using an old Dualsky XM3548 brushless motor with XC4018 ESC supplied by a 3S 2200mAH Lipo.
(There is plenty of space to fit a larger capacity battery if needed).
With a fixed 2 blade 9x6 Master Airscrew prop, this combination gives just over 300w on the wattmeter, with just over 30A at full throttle.
Max motor efficiency current is 35A, so a little more is available, but max current is 40A.

With the model (currently still less it’s tailwheel assembly & Rx) balanced (2200 battery fully forward), the overall weight comes in at 1.8Kg (4lbs), including about 200g of lead hot glued to the bottom of the motor bay.

Currently trying to find a tailwheel assembly with a bracket small enough the match the fuselage rear end, which can also be fitted with a 15mm tailwheel. (Cliff May need to 3D print a slightly smaller version of the Commercial unit I have!)
Also need to find & fit a couple of small outrigger wheels - otherwise it’s about ready to commit to aviation once a receiver has been fitted & set up.

Re: SF33 1/6 scale

Posted: 04 Jul 2020, 12:19
by StephenB
Peter, did you resolve the wheel issues and get this airborne? I ask as I'm thinking of having a crack at one, it's a handy size for ease of transport and rigging so I'd be interested to know how it flies on your power set-up.

Re: SF33 1/6 scale

Posted: 04 Jul 2020, 13:34
by Peter Balcombe
Hi Stephen,
Yes, the wheels were sorted (using commercial types as far as I can remember & Cliff Evans took delivery.
I am pretty sure that it was flown ok by Cliff last year, but will wait for him to comment on the flying aspects.
Peter

Re: SF33 1/6 scale

Posted: 04 Jul 2020, 13:53
by Cliff Evans
I have not managed to get it to take off from the ground, there is not enough prop clearance. I just hand launch. Flys well no vices at all.

Re: SF33 1/6 scale

Posted: 04 Jul 2020, 14:50
by StephenB
Thanks Peter and Cliff - that answered another question as to whether it would r.o.g. I thought prop clearance may be an issue. How do the outriggers fare - are they vulnerable on landing??

Re: SF33 1/6 scale

Posted: 04 Jul 2020, 21:45
by Cliff Evans
Really depends on how long the grass is! Not really had any problems with them.

Re: SF33 1/6 scale

Posted: 12 Jul 2020, 18:38
by IanT-White
Peter , I have a two thirds scale SF33 ,which flies really well , with a King 190 twin , with onboard electric starter takes off very easily and climbs 6 to 7 metres second
Occasionally the outriders bend if they catch a tuft but easily straightened ,115 lbs
Good luck with your flights
Ian Turney-White

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 13:39
by StephenB
No mention of control throws on Cliff's plan, what did you dial in Peter?

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 15:30
by Peter Balcombe
Stephen, I cannot remember exactly, as I passed the model over to Cliff with servos linked up & checked using a servo tester, but no receiver in place, leaving him to set up the Rx and actual control throws.
I would have given Cliff something like as much rudder as I could reasonably get mechanically say 3/4” or more each way.
Elevators would have been about 1/4-3/8” each way & ailerons probably something like 3/8” up & 3/16” or so down.
(I basically set up what looked enough travel & left it up to Cliff to use what he thought necessary from there)

I expect that Cliff will be along soon to advise what he actually used.

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 17:29
by Cliff Evans
rudder 3/4” each way.
Elevator 3/8" each way
Aileronse 3/8” up 3/16” down

Is exactly as mine is set up 65% expo on elevator.

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 17:35
by Peter Balcombe
Cliff Evans wrote:
12 Oct 2020, 17:29
rudder 3/4” each way.
Elevator 3/8" each way
Aileronse 3/8” up 3/16” down
Wow, that was a good guess 8-)

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 20:45
by StephenB
Many thanks Peter and Cliff, a little less than I had "estimated", so probably saved a fraught first flight experience!

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 20:47
by Cliff Evans
The elevator is still quite lively!

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 22:21
by StephenB
Cliff Evans wrote:
12 Oct 2020, 20:47
The elevator is still quite lively!
Noted!

Re: SF33 1/6 scale

Posted: 12 Oct 2020, 23:36
by Tonyw51
G'day Peter and Hi to Stephen & Cliff,

Great to see your post on control throws as I had been mulling over that recently. It is all somewhat academic at this stage as we are still in lock-down and the field has been closed since June. I have not had the opportunity to take the model to my local model shop to discuss fit up of a couple of final items and frustration is starting to set in. Anyway, I have attached a couple of photos of my example. This is my first attempt at a scratch build and I am quite pleased with the result. (My second scratch build is a "Wood Pecker" out of RCM&E November 2017, photo attached of the maiden flight. The field was closed again in the following week).

Cheers,
Tony W

Re: SF33 1/6 scale

Posted: 13 Oct 2020, 08:42
by Peter Balcombe
Looks very nice Tony.
I hope all goes ok when you get the chance for the maiden.
Peter

Re: SF33 1/6 scale

Posted: 13 Oct 2020, 09:16
by Cliff Evans
Looks good Tony.

Re: SF33 1/6 scale

Posted: 13 Oct 2020, 09:30
by StephenB
Nice job on the SF33 Tony, very striking colour scheme. Let us know how the maiden goes.

Re: SF33 1/6 scale

Posted: 14 Oct 2020, 01:18
by Tonyw51
Thanks. Yes I shall report the event just as soon as it can happen.

Cheers

Re: SF33 1/6 scale

Posted: 25 Nov 2020, 09:12
by styx2020
Tonyw51 wrote:
09 Jan 2019, 02:39
G'day Peter & Chris,
Much excitement in the workshop today with the arrival of my short kit from SC Models. So now have the plans printed, mirrored and printed again (and they are a perfect match), the short kit and the canopy "in the mail" from Sarick. I am in the process of completing a Brolga (2.0 mtr. Australian model) and as soon as it has had its maiden flight I shall start on the SF-33.

I am very happy with the quality of laser cutting and I shall start to rifle though the stores of strip and sheet to put together a complete kit, so all is looking good
Hi Tony,
Just received my set of laser cut parts for the SF33. You mentioned in your comments about printing and mirroring the plans and I was wondering how you went about this. I have trouble with large sheets of paper in my small workshop and I am reluctant to cut the plan up until I have a copy of it.

Re: SF33 1/6 scale

Posted: 25 Nov 2020, 10:04
by Tonyw51
Hi styx2020,
I went to OfficeWorks here in Melbourne and they were able to do the job for me. I had them do 2 copies of both original and mirror so I could cut and hack.

I have had a couple of sessions at the paddock to get my fingers and brain acting together again and am now waiting on the weather to improve for the SF33 maiden post our pandemic lockdown.
Cheers,
Tonyw51