Spitfire by Cambrian Funfighters Electric Version

[Peter Garsden]

 

I have been wanting to build a Cambrian Funfighter ever since I saw one fly at   great speed at a PSS event on the Orme. I decided to make this one dual purpose. I am going to install a brushless motor, ESC, and 3 cell 2200mah LIPO at the front instead of ballast in the nose so that I can fly it in the back field at the farm, but I will also be able to take the prop off and fly it at PSS events. I am sure it will need at least a 20mph wind.

 

I have decided to go for the above version of the Spitfire which is a Mark 1 manufactured in 1941, and, I think, still flying on the display circuit. It's history is described here. It was used in the war as a training aircraft, had one or two accidents causing damage which was repaired. It was bought privately after the war for £10. The stripey nose was removed and none scale parts applied. It was used in the Battle of Britain film in 1969, then converted back to the Mark 1 exact scale original.

[Peter Garsden]

I did not know whether to put this in the PSS Build Blog or Warbird Kit section so opted for the Warbird Kit as it will have a motor. I chose the Spitfire basically because it was the only Funfighter Cambrian had in stock. I was going to go for the Zero but there was no stock, so this was Hobson's choice. They now have a Hurricane and a Mustang but nothing else.

 

The kit is very reasonably priced at £75.99, and arrived quickly. It consists of some very well cut foam wings with high quality beech (I think) veneer. There is a full size plan for IC versions then a smaller second sheet showing the amendments and parts for the electric version omitting the fuel tank and throttle servo, which is what I am going to use. 

 

 

The box is packed with bits all cut out which is not what I am used to in that I usually scratch build from a wood pack. Quite a luxury! So this will be a  quick build as the method of construction is simple and familiar. Each type of part like balsa, plywood, and accessory have their own bag, almost as though you feel that you won't need to check the part list for anything missing.

 

 

As you can see a very comprehensive instruction manual with everything you need to build even if you are a complete beginner, which I am not. Lots of easy to follow pictures and wording for each step of the way. Obviously a clear canopy so we can display a scale pilot but no Pilot.

 

It says that you can add a rudder, which I think I will use as it is very useful for stall turns when PSS soaring. I am also going to change the one aileron servo for 2 so I can use Spoilerons when PSS'ing.

[Phil Cooke]

Watching with interest Pete, I have an identical kit in a box here which I must build one day - mine pre-dates the electrification update (or its missing?) but no bother mine will be PSS when I do get round to it.  Happy modelling!!

[Graham Davies 3]

Hi Pete,

My wife bought me this kit for Christmas and it's been in regular service since lockdown ended. I love flying it; it's stable, fast and fun and certainly has enough 'spitfire-ness' to be evocative.

 

Some things worth sharing:

• It's no lightweight, and the choice of lightply fuselage sides does not help the balance. I have seriously struggled to get it to balance (so much so that my first flight ended in disaster!). If I do another one I would use 3/32" balsa for the fus with 1/32" ply doublers frome behind the wing to the bulkhead...
• ...to prevent a clear breakpoint at the leading edge. My first disastrous flight snapped the fuselage at the wing leading edge; a ply doubler here would have prevented that (a lighter rear end would have prevented the need for it!)
• There's no room for ballast. I needed 2-3 oz and fitting it inside the cowl area took some imagination. 
• Go with the rudder. Way easier to launch right handed with your thumb on the rudder to catch the swing. Also gives you another servo to get up front!
• Plan for the servos to be as far forward as you can get them
• There's also not a lot of option for ventilation. I made a scale-ish Mk2 radiator as an air outlet (hole through the wing) but it still gets worryingly warm inside.

Otherwise I'm sure you'll love it

 

Graham

[Mark Turner 12]

Hi Graham

 

What did you cover it in, I keep swinging between glass cloth, epoxy or water based varnish or back to tissue.

 

thanks Mark

 

[Graham Davies 3]

Hi Mark,

 

None of the above! 38g matt finish laminating film, painted with emulsion paint. 

 

Who would want to paint their house in those colours?!?

 

Graham

[martin collins 1]

These are great kits, i built the ME109, i put a hot motor in it with a 3s 2200mah pack, flies very fast and the climb rate is awesome, weight came out at 2.8lbs, covering was doped Polyspan and Tamiya Acrylic paint. Going to pick up a Spitfire or Hurricane kit at North Weald Wings and Wheels next month..............

[Peter Garsden]

Thanks Graham - top tips. I was wondering about the 1/8" Fuselage sides I must admit and will probably take your advice. I was aware of the C of G problem as I have read your blog. I am going for the Rudder as I like to do stall turns when sloping. Without a rudder it is easy to stall it instead. I have ordered an extra snake from SLEC.

 

Graham did you install the servos in the recommended place as I don't think there is much option?

 

I think it will be important to keep the weight down for when I take it PSS ing and pushing the servos forward and using balsa fuselage sides with doublers should work. I am thinking of using 25gram fibreglass cloth and resin finished off with airbrushing so that should help strength if we go for balsa sides. Might stretch to 1/8" balsa which I have in stock. Don't think it will make much difference.

 

And Martin, the ME109 looks wonderful. The Spit also has some great finishing touches. Will try to emulate with my airbrush.

[Peter Garsden]

3 hours ago, Phil Cooke said:

Watching with interest Pete, I have an identical kit in a box here which I must build one day - mine pre-dates the electrification update (or its missing?) but no bother mine will be PSS when I do get round to it.  Happy modelling!!

I can copy it and send it to you if you wish Phil?

 

[Graham Davies 3]

Hi Peter,

First flight was with the servos as recommended. After that I moved them hard up in front of F2, so in the battery box area. It took a bit of work to keep them clear of everything else, but anything ahead of the CofG helped.

 

1/8" balsa will be fine. It will also help to shape the lower rear fuselage which will also save some weight (and look better!). To me, balsa/ ply doubler puts the strength where it's needed, not the weight where it isn't.

 

I do recall that the lower fuselage sheeting was a bit heavy too. Some nice soft stock here would help.

 

The ME109 looks great, doesn't it?

 

I think you've seen my post, but the finishing is a mixture of gel pens and chalk. Really enjoyed that process (thanks to Richard Wells), and it still looks good 30+ flights later.

 

Graham

[Eric Robson]

15 hours ago, Graham Davies 3 said:

Hi Mark,

 

None of the above! 38g matt finish laminating film, painted with emulsion paint. 

 

Who would want to paint their house in those colours?!?

 

Graham

I got funny looks when I took  a sample of Kyosho Spitfire covering and asked for a match at B&Q . It turned out not very good as I think the gloss surface confused the computer. I did have a match made for olive drab with a matt sample and it turned out perfect. They are very good for matching warbird colours and a 236 ml pot of emulsion costs £3 compared with Humbrol at £3 for 14ml.

[Graham Davies 3]

Hi Eric,

Paul Johnson suggested I make up a swatch card by painting the 'best nearest' paint I can find onto white card, and matching to this. I like this idea and am trying this for my Yak3. I've got some MIG and Vallejo acrylic paints in those little 17cc pots used for airbrushing, so will use those. We'll get those matched and I'll let you know how it goes.

 

I've got a cheapy paintgun that will allow me to spray emulsion, so that should kit me out.

[Peter Garsden]

Graham I am wondering whether to stick with the light ply. The difference in weight of each side when compared with balsa is 35 grams for the ply and 21 grams for the balsa. When one adds the doublers in 1/32 ply which I mocked up the weight goes up to 41grams so would it end up heavier? I suppose the argument is that the weight distribution is better. I think I would have to adjust the profile of a lot of formers, also. Just wondering if it is worth it. I am thinking of making some holes in the rear fuselage sides to lose some weight from the back end. Mmmm...

 

Anyway, I have made a start by gluing the leading and trailing edges to the wings with masking tape and  Titebond aliphatic resin - fancy PVA.

 

Edited May 5, 2021 by Peter Garsden

[martin collins 1]

Good choice, i used aliphatic on my build, watching with interest, i love these FunFighters, i have a Cambria KI-61 in my kit stash to build as well.

[leccyflyer]

5 hours ago, Eric Robson said:

I got funny looks when I took  a sample of Kyosho Spitfire covering and asked for a match at B&Q . It turned out not very good as I think the gloss surface confused the computer. I did have a match made for olive drab with a matt sample and it turned out perfect. They are very good for matching warbird colours and a 236 ml pot of emulsion costs £3 compared with Humbrol at £3 for 14ml.

I've never had any funny questions on my trips to get Valspar match pots to match the colours on my foamie warbirds. All except the dark green on my PZ Mosquito fin turned out as a good match - that dark green was quite a bit darker than the original. It's a brilliant source for touch up paints or even to paint a whole model. One thing to note is that some of the emulsions do carry an agent which makes their colour very different before it dries. The RAF light grey that I got for my Eurofighter went on almost bright pink when applied, but dried to the perfect light grey shade.

[Graham Davies 3]

4 hours ago, Peter Garsden said:

Graham I am wondering whether to stick with the light ply. The difference in weight of each side when compared with balsa is 35 grams for the ply and 21 grams for the balsa. When one adds the doublers in 1/32 ply which I mocked up the weight goes up to 41grams so would it end up heavier? I suppose the argument is that the weight distribution is better. I think I would have to adjust the profile of a lot of formers, also. Just wondering if it is worth it. I am thinking of making some holes in the rear fuselage sides to lose some weight from the back end. Mmmm...

 

 

 

 

 

You might be right Peter. I think for me, the weight distribution is key. It may be a PITA to make the change though. Cutting a few holes at the back might be a good idea though.

[Peter Garsden]

Graham, having ummed and awed for a couple of days I am going to replace the fuselage sides with 2mm balsa lined with 1/32 ply or .8mm in new money to behind the wing. It has to make sense. Thank you for the recommendation. I have some balsa in stock so no problem.

 

On with the build. Next task is to plane and sand the leading edges to shape - but not the trailing edges. Because the grain is opposed on the tips I could not understand why this is the instruction direction. I think it is because the trailing edge of the tips can fluctuate to accomodate the thickness of the 2 pieces of balsa. I followed the instruction and it does make sense.

 

I used the masking tape method to plane the leading edge. This is such a good tip and avoids scoring the veneer of foam wings with the plane blade. Instead you score the masking tape.

 

 

Then one adds the tips. Instructions say line up the leading edges of the 2 tip pieces, but in reality I set back the thinner piece to avoid any gaps, as you can see. I used aliphatic to glue the 2 pieces together, then used 20 minute epoxy with some microfibres mixed in to glue the tips on. Don't use aliphatic. It is not strong enough to attach the tips. Very good for planed surfaces to be glued together but not tips. I have tried it and the joint has failed on previous models.

 

 

[Graham Davies 3]

Looking good Peter.

 

It looks like I can now sort out the ballast issue. On my final flight this evening, rather than break the prop, which happens depressingly regularly, the firewall came off! I have had various balance/ vibration issues, so I think this has been coming. The good thing is I now have unhindered access to the underside of the motor box so can relocate the lead and kill off the vibration issues once and for all.

 

Yours will be lighter, particularly at the rear, so shouldn't suffer these problems.

 

Regardless of all this, it does fly really well...

[Peter Garsden]

Sorry to hear about that Graham. 

 

Next job is the aileron crank. They are thin so must be careful when drilling. 

 

First I measured up and the ailerons are about 4mm too longer than plan so cut them down.  Important to cut down and insert the bearing tube BEFORE you bend the wire and cut to size. Also rough up the tube for gluing.

 

 

I used a small Permagrit 3mm file to make the groove once marked and scored. Although the photo shows the file in the dremmel I ended up using a shorter round  3mm grinding tool

 

 

Next I will epoxy it in using Vaseline on the wire to stop splurge and jamming 

[Graham Davies 3]

It was but a scratch Peter, a flesh wound if you will...

 

I was/ am concerned about the lack of material for the torque rod to engage with. It may be worth a small piece of ply inlaid to support this area. Mine have so far held up but there really isn't much to bite into.

 

As an aside, mine now has a folding prop. The breakages were getting silly. The model lands flat and there is no way of knowing where the blades will be at point of first contact. Others have been luckier than me, but a prop every 3-4 flights is a bit much! I tried a 10x6; same as I sport on the 800kv/3S set up I've been using. However, it's a bit power hungry so rather than risk the smoke getting out, I've gone for a 9x6. It's pulling 38A static; around 400W so should be good. May fly tonight so will report back

 

Graham

[Peter Garsden]

A folding prop is a brilliant idea Graham as I wouldn't need to change it for flying PSS. Will go for that thanks. Great ideas by the way just keep them coming. I agree with you re ailerons, however I am going for 25 gram fibreglass cloth and resin finish so I can always add a piece of cloth to reinforce that area. That is what I will do because the ailerons have a serious lack of depth to be inlaying ply. I usually end up puncturing the surface as well, just to make things worse, but we will just have to see as this is next job.

 

[Graham Davies 3]

I made a little jig to hold the aileron upright and square and then drilled with my pillar drill to a depth stop. I was worried about getting central or breaking though. It's stable though, and aileron throws are tiny so seems fine. I reinforced the hole with some cyano too.

 

Graham

[Peter Garsden]

Thanks Graham. I also used my pillar drill with a piece of masking tape to mark the depth, which worked a treat. Never done it this way before and always got into trouble with it. Not this time so thank you.

 

I used a combination of my David Plane, and Proxxon Shoe Sander to shape the ailerons.

 

I made a cradle by using the profile of the trailing edge from the wing saddles, mixed up some 20 minute Epoxy and Microfibres, glued the wings together but had to sand them down quite a lot first which was strange.

 

This morning I checked everything and to my horror realised that I had used 19mm instead of 90mm - I was so annoyed. I thought they looked a bit flat. If I had just glued them together as they are cut I would have been fine. They say measure twice cut once - such a clot. So I had to use my saw to part the wings again. The glue was not hard so I was able to peel it off because it was not hard enough to sand. What a mess. Anyway, I used my circular sander to angle it up again and I have now re-glued it with an enlarged tip cradle and some weight as you can see.

 

In order to keep the 2 wings together I used some wide 3M clear tape top and bottom. Parcel tape would do. It is important that there is no twist in the wings which would be a disaster. It also stops oozing then a lot of sanding.

 

 

 

[Peter Garsden]

Next is the reinforcement 1.5mm ply piece to strengthen the holes for the wing bolts. This has to wrap over the wing dihedral. The instructions don't say score it in the middle to bend it over the join but this is the only way it will fit.

 

 

The instructions say attach the wing bandage with PVA - diluted with water I presume whereas I usually use fibreglass resin, though I have heard it argued that PVA is all you need. I will try it and see how we go, but it has to be thoroughly soaked not just glued on with the PVA which does need saying for the beginner or inexperienced builder.

[Graham Davies 3]

Looking good Peter.

 

I did the same with the ply reinforcement. I think i used fine glass cloth and epoxy.

 

Regarding the folding prop (I need to give credit to Ron Gray for that one!), I went down an inch from the 10x6 I had been churning though because the 10x6 folder draws a lot more current. I've got a 9x6 on there, and it's fine in the air, but lacks a bit of acceleration. As such, this evening's launches were followed by the lowest of low passes, and the gentle sound of puckering...

 

Graham