Construction help

Guys
I am starting the build of my spitfire (ARTF) and have some servo-less retracts arriving today.
I removed the covering from the wheel recesses and the section that the retracts fit into is made of balsa!
The 4 screws that will hold the units actually screw into balsa
Is that a total waste of time?
The model AUW is about 3.3kgs and I don't want to start hacking into the wings if I can help it.
Is there anything like a wood hardener I could use to beef the bits up?

I know there was a thread about retracts the other day, but I thought a fresh one might attract more advice.

Thanks in advance
HF

i am afraid you will need to let some beech into the wing to take the retracts.
balsa will not be strong enough, sorry.
some Cyrano soaked into the balsa will harden it , but i doubt enough for a model of that size.
did it come with fixed uc when you bought it or was it a belly lander.

Hi Tony - it's designed for an undercarriage and came with mechanical retracts.
I decided to go the servo-less route for ease, but was (I must admit) surprised at the use of balsa in that spot.



This isn't my actual one - it's off the website advert (by the way)

Am I going to have to remove the wing covering then?

well if it came with retracts fitted, then i would just glue a bit of extra wood under the existing mounts, just to beef them up a touch and screw the electric ones in.

They weren't actually fitted - the model is still in bits in the box.
I'll take a close up photo and post it shortly.
I'm liking the idea of gluing rather than removing wing fabric
What about some nice ply in there?
(I don't possess any beech at the moment!)

You'll definitely need to do something to strengthen the balsa. I'm with Tony in that wood underneath might do it. I'd fix as large a piece of thin plywood as I can fit into the space available under the balsa and the same on top.

That looks like liteply to me.

Agreed - you can see the laminations.
Whether it is strong enough is anybodies guess but the original designer obviously thought it was.
What make is it?

Unfortunately I think it is balsa
It's a bit harder than I remember balsa being - it's years and years since I used it, but there's no apparent layering visible.
The good news is it looks like it wouldn't be too hard to cut it out and replace with some ply??
Whaddya reckon guys?

Either leave it as is and skin it either side with thin ply, or cut it out and substitute beech in it's place.

Typical ARTF ... look at the glue on those bearers..... or rather the absence of it.

Agreed - not good!
So, next question guys, what's the wisdom here.

This shot is of the retracts in place. Wrong size, so I will need to cut away one of the cross sections to get the motor housing recessed, but if I use the unit straight in the existing cut outs, I will have to (somehow) bend the shaft to match the angle of the wheel housing, or is it best to put the unit in at an angle to match that, leaving the shaft as it is and having to re-cut the position of the mount?
Does that make sense?
Also, I will have to shorten the shaft, yes?

Sorry for the dumb questions, but this is my first attempt.

Six of one, half dozen of the other I think ... personally, I'd leave the mount square & very carefully open up the loop slightly until the shaft ran through the center of the wheel hub position.... if you know what I mean?
It would then be easy to glue some balsa sheet or cardboard to the shaft itself to make it a tidy fit.
If you do it this way ... don't bend open the loop whilst holding the mount... get a pair of fine nosed pliers & only hold the shaft itself.

Pol.

Thanks for that Pol
Those balsa sections are 9mm.
Presuming they will dig out fairly easily, I have some 11mm ply that I could cut to fit.
Would that be good or should I hold out and locate some beech from somewhere?

Hoverfly wrote: Thanks for that Pol
Those balsa sections are 9mm.
Presuming they will dig out fairly easily, I have some 11mm ply that I could cut to fit.
Would that be good or should I hold out and locate some beech from somewhere?

I honestly don't think they would have used balsa for those bearers / mounts. It may not be beech, but it must be a wood that' a lot stronger than balsa?????
I'd mark the screw positions & drill a pilot hole .... try a screw in it & see how strong it is .... if you can pull the screw out, then they need replacing completely.... with some glue this time.