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SIG Rascal 110" refurb and electrification

The old Rascal needs a new heart and new clothes

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Ron Gray08/04/2020 20:09:50
2532 forum posts
1013 photos


I bought the SIG Rascal 110” in late summer of 2019, it had a 2 stroke petrol engine fitted and due to its age (10 years+ ?) I decided that, at some point, I would strip the faded covering off, re-cover it and probably fit a 4 stroke petrol engine. Earlier this year I got round to flying it for the first time (for me) and to be honest it wasn’t a very pleasant experience. The engine was a CRRC 26 and was both noisy and messy and didn’t have a great deal of grunt. The flight did show that the model had potential so the next step was to re-engine it. I then had a complete about turn and decided to electrify it, I set myself the challenge of powering it with 2 x 5s 5000mAh LiPos as these are what I use in my F3A ‘plane. After lots of calculations using eCalc I decided on the Turnigy G160 as the motor to power it with a 120a ESC (well over the top!). The next challenge was to fit the batteries, I firstly cut an access panel out from under the nose but when I checked the CG I needed to have the batteries quite a way back in the cabin area which meant that the under nose access hatch wasn’t ideal! In the end I carefully removed one of the side windows (both have gone yellow and are extremely brittle, they’re on the list to be replaced but I will have to wait another 3 months to get them from the ‘states). In order to fit the batteries I built an angled platform with 3D printed runners and a sliding 3D printed tray, the idea being that I could reach in through the side window and get to the batteries that way. The photo above shows the Rascal with leccy power (note the new canopy which I was fortunate to get from Pegasus).

Shots showing the battery tray arrangement.




Shot showing, outside of the fuse,  the 3D printed tray in the side rails fixed to the ply platform.


I then took the Rascal out for its first electric flight and what a beauty, plenty of grunt to do all aeros and flight times in the region of 15 minutes. So next job was to strip off the covering and re do it, plus I wanted to have better access for the removal of the batteries as the side window approach was a bit of a faff.

Stripping started but in my haste I just started to peel the old film off, I should have used a hot air gun as this would have taken off more of the colour too! 

started stripping.jpg

tail end.jpg

Hmm, pull pull wire wrong side!

wrong side.jpg

It soon became apparent that there were a few areas where damage had been repaired, or need repairing.


damge 02.jpg

damage 03.jpg

Oh dear!

fin tail junction.jpg

Some of the previous repairs (U/C ripped out!) needed the hot air gun (which I was now using to remove the covering)

heat gun.jpg

Eventually the covering was removed so the repair works can commence.


Edited By Ron Gray on 08/04/2020 20:22:09

john stones 1 Moderator08/04/2020 20:51:21
11933 forum posts
1531 photos

A model i quite like, petrol n a can for me though.

Ron Gray08/04/2020 21:11:05
2532 forum posts
1013 photos

Yeah, I know what you mean John and I do have an ideal 4 stroke petrol for it, but I fancied the challenge. Tbh, I couldn’t fault its performance, plenty of power plus a good flight time, plus I get to exercise my under used 5s packs.

john stones 1 Moderator08/04/2020 21:25:59
11933 forum posts
1531 photos

Not faulting it Ron, I just never enjoyed my flirt with lecky.

Andrew Price 208/04/2020 21:47:57
840 forum posts

Signing in.

Ron Gray08/04/2020 22:53:30
2532 forum posts
1013 photos

@ John - I certainly miss the sound of a Laser 4 stroke!

@ Andrew - welcome aboard!

Dale Bradly08/04/2020 23:53:12
55 forum posts
13 photos

I had a pair of the 72" Rascals (or whatever they called it that week), the first with a .52 4st, and the second electric. The electric was by far the better flyer, just went so well. Always wanted the bigger one, one day maybe

Ron Gray09/04/2020 22:35:20
2532 forum posts
1013 photos

I had decided that the means of access to get the batteries in and out needed to change so out with the knife and off with the top half of the fuse. Just as well really as the balsa in this area was more than a bit tired.



This now gives me a nice opening through which the 2 x 5s 5000mAh batteries can be passed


I then spent a lot of time filling and sanding, filling and sanding and so on, until I got to this stage



Not just filling but cutting out weak or damaged balsa and splicing in new bits



It was then that I noticed the fin wasn’t vertical (which would explain why I had to dial in some trim when I flew it).


What to do? I had spent quite a while filling the poor balsa around the junction of fin to tailplane so I was thinking maybe steam or wet and bend the fin vertical. In the end I did the ‘correct’ thing and cut the fin away from the fuse.


I was glad that I did as there was a split in the fin which some superphatic fixed.


But I wasn’t happy with the way that SIG had constructed the fin as all 3 layers were formed from vertical grain balsa. So I removed a section from both the outer skins and replaced them with balsa with the grain running horizontally. This also gave me a better ‘tongue’ for sticking back in the fuse.




For the engine mounting 'box' I first produced the parts using the 3D printer, then used those as teh templates for the permanent plywood ones.





Which is fine but with the fuse now hacked about behind the firewall I'm a bit concerned about a lack of support for the engine box so that's the next job!

john stones 1 Moderator09/04/2020 23:04:38
11933 forum posts
1531 photos

Nice refurbing Ron, I looked one up yesterday, saw the price n went right off one. sad rose

Ron Gray10/04/2020 22:35:24
2532 forum posts
1013 photos

It's been slow progress today, but progress is progress!

To provide some additional support for the motor box I used some alloy rods that were recovered from an old bird feeder we were throwing out a couple of years ago, I just knew those perches would be useful one day. So a bit of bending, hammering and drilling and..


Next on the agenda was to fill in the underside of the fuse where I had removed the old balsa covering but I had to pack in out as the U/C mounting plate is thicker.



At this point my attention should have gone onto the removable battery hatch / windscreen but I need some more thinking time for that as I'm not sure how I'm going to make it work. So I decided to make a start on the covering, something that I enjoy doing but haven't had to cover a bare frame (apart from repairs) for years.

Red applied to fin, rudder and elevator.


And then the film trim. I used my Top Flite Woodpecker on the red film before applying the white. This ensures that no air pockets are trapped between the 2 layers of film.

top flite woodpecker.jpg


Peter Jenkins10/04/2020 23:07:00
1725 forum posts
314 photos

Where did you get the Woodpecker from Ron?

Ron Gray11/04/2020 08:12:19
2532 forum posts
1013 photos

I got mine from Tower Hobbies about 3 years ago, when buying stuff from the 'States was still reasonably good value for money!

Ron Gray13/04/2020 22:55:10
2532 forum posts
1013 photos

Covering to the tailplane and I remembered a tip I was given years ago to assist when covering open frames such as wings, drill some holes to allow the hot air to escape which prevents the film blowing up like a balloon




Use of the woodpecker on the film before applying the trim film


And trim film applied, no bubbles!



And another tip I remembered, apply a narrow strip of film to junctions of surfaces which makes applying the final film less critical!


When I dismantled the Rascal I noticed that as well as a rear cutout for the elevator servo there was one on the other side of the fuse, presumably SIG made it that way in case anyone wanted that instead of a pull pull system for the rudder. So I decided that is what I will be doing, there’s no problem with having that weight in the tail as there is plenty of room to move the flight batteries forward, in fact I would rathe they were as that will make it easier changing them! However, I didn’t like the idea of two lots of servo cables dangling around in the fuse so I created a cable ‘duct’ using to inner plastic tubes that some Christmas marzipan was rolled on!


You can just see it glued into the bottom of the fuse




And then back to the covering, first the red side panels.


Top and bottom first, these were easy although the bottom piece is 1800mm long!



The side pieces had to have the cutout formed for the red panels and this was a right pain to get right, lots of measuring and checking before cutting. In fact I ended up placing the uncut sheet on the fuse then shining a torch through from underneath so that I could see, and mark where the cutout should go. Then back to the cutting board and using various pots and a soldering iron holder was able to cut the radiuses corners to a very close match of the original.


Many blades later and a lot of time later (2 hours per side!) I ended up with this


Work has now started on a new battery hatch using new formers created on my 3D printer



Dave Cunnington13/04/2020 23:08:31
243 forum posts
86 photos

Superb job Ray, all credit to you

Peter Jenkins14/04/2020 01:06:34
1725 forum posts
314 photos

Great job Ron.

Who's Ray Dave?

john stones 1 Moderator14/04/2020 15:43:02
11933 forum posts
1531 photos

Nice job Ron, that Porcupine looks a fearsome tool. surprise

Ron Gray15/04/2020 20:28:19
2532 forum posts
1013 photos

Thanks guys, much appreciated.

I've started on the wings now but progress is slow due to the amount of work I'm going to have to do to one of them sad. If I get time I'll put the photos up on here later on tonight.

Ron Gray15/04/2020 22:50:32
2532 forum posts
1013 photos

At first look, the wings look to be in fairly good condition albeit the red panels are a bit faded. However it is obvious that, over the years, repairs have been made.




Stripping back the covering on the starboard section revealed a few areas of slight damage, mainly, I would guess, due to rough handling.




Nothing major so I continued to clean up the frame using my small Hobby King heat gun and scraper.fullsizeoutput_13f0.jpeg


The advantage of this tool is that it is a lot more controllable and less fierce than the large heat gun I used on the fuse.


Next I carried out the same on the port wing but ended up in a much different situation! It is obvious that the Rascal had quite a severe crash at some point in its history, one that, by the looks of it, broke the wing in half just outboard from the root. I suspect that it came in hard onto the wing tip (also damaged) and this caused the wing to shear and was also the cause of the damage to the fuse, just above the windscreen. The following pictures tell the story.







Having removed the covering I then set about cutting out the repair balsa mainly so that I could see ‘underneath the skin’ to see the exact extent of the damage and the repairs. I ended up with this.




You can see that the TE section, inboard of etc aileron has mostly been cut away.


As I have to carry out fairly extensive repairs in this area I have decided to convert the wings to have flaps. Later Rascals are now supplied with flaps so it’s more of an upgrade really! I now need to order some more balsa from SLEC as I haven’t got any of teh correct thickness of the correct grade (hard).

Back in the house I tried my hand at decal cutting using my wife’s cutting machine (Silhouette Cameo) and this was the result.



Edited By Ron Gray on 15/04/2020 22:51:44

Ron Gray17/04/2020 14:46:29
2532 forum posts
1013 photos

Whilst waiting for the balsa delivery from SLEC (just arrived - thanks guys) I decided to finish off the battery hatch or 'bonnet'.

If you recall I cut off the top of the fuse to allow better access for the flight batteries.


But I wasn’t too happy with either the condition of the existing or the shape of the rear of it as a ‘real’ dashboard certainly wouldn’t be sloping back the way this one is, and yes I know this isn’t a scale model but I want it to look a little bit more scale! So I remade the hatch using a combination of 3D printed formers and balsa.



The sheet balsa for covering the hatch was cut and joined together using teh tried and tested method of tape one side, fold back, glue then lay flat with weights until dry.



Once dry I then wet the outside of the sheet and bent it over the formers and left it to dry. This gives it the basic curved shape and makes sticking it onto the framework easier.


Once stuck on and dry I offered it up to the fuse and also tried the fit of the windscreen



The windscreen is something I’ve got to work on! I’ve ordered new one from SIG but don’t expect it to arrive any day soon so I’ll try and repair it or may even have a go at 3D printing a new one.

Meanwhile back on with the ‘bonnet’ and covering time.



Followed with the trim, I used some Solartrim as I don’t have any red film in stock.


And yes, there is a slight crease in the covering and you may ask why doesn’t it got down to the bottom edge. The reason for this is that I don’t like an edge of film right on a small edge of structure as it can lift. Well that’s the official reason but the truth is I cut it too short!


And a trial fit to see what it looks like


I quite like it!

Whilst all this was going on I tried my hand at 3D printing some side windows as the originals were in a poor way, yellowed and cracked. I'v got new ones ordered along with the 'screen from SIG but thought I'd have a go anyway.



A good fit but a bit 'frosted', still I think they are better than the old ones.

Ron Gray17/04/2020 16:47:35
2532 forum posts
1013 photos

Whilst the 3D printer was still 'hot' I got a bit carried away.

Saw this picture on the ‘net so decided to design a dash around it


In my 3D print software, Fusion 360, I designed a dash with cut outs for some of the instruments


Printed the 'net image onto some paper, cut it out then covered it with some clear packing tape to give the illusion of glass.


The 3D printed dash turned out OK


So stuck the image to the back of it


Happy with that so stuck it to the 'bonnet'.


Now it even has the potential for night flying


Off to check the SLEC delivery now so that I can get back to the wing re-build / repairs.


I'm guessing that by now the vast majority of formulites are bored stiff with my posts so I'll refrain from putting more up for a few days.

Edited By Ron Gray on 17/04/2020 16:48:19

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