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Israeli Air Force A4 Skyhawk - Shalom


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Well, the vinegar worked really well and the 3mm sheet bent into a perfect shape. I only needed one or two pins and some cryano to hold in position. The cryano accelerator is a godsend to hold the wood in position and set it. I also have a very small gap to fill at the edge of the joins.

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And so for the snakes. I was going to use some left over carbon rod and tube, but I didn't think there would be enough pudding at the tail. So I ordered a Sullivan set from Blackburn Models - such good service. Phil used the non-flexible type which is blue, but I got the red one which is flexible.

I followed Phil's advice and made some supports for the tube out of 1/2 inch with a slot positioned either side of F5.

I used my handy space measurers to judge the width of the fuselage, which is wider than by the doublers.

I also tried the fit of the fin and tailplane to judge the snake angle which is fine.

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I was not looking forward to attaching the fillets of balsa - having decided that balsa fillets are better than filler. I cut some 1/8" sq, then tried to make them into triangular with little success. I carved some off the corner and fixed them on the gaps round the intakes.

Next problem was how to sand them down. I used my handy fine grade Permagrit file which worked a treat albeit leaving grooves here and there in the fuselage sides.

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I then attached the doublers to the fin whilst leaving the tailplane detachable for later. It was crucial to get the angle of the tailplane right and the fin perpendicular. I used my engineer's squares and Super Phatic Glue and pins. It looked just right.



Thought I would photo and assembly - looks more like a Skyhawk. Next job is sanding down and planing methinks.

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Tonight was sanding to shape and filing with the fine Permagrit file - much better than the block - a must have tool.

I followed Phil's lines and dimensions for the planing which really do help.

buy when priests, wll o tde h[t I was wary of Phil's holes in the top sheeting, but decided to plane down to the line to see what would happen. The answer is that I got a hole albeit very small on one side but not the other? Why? When I looked at the lining of the intakes, I realised that the outer sheeting was higher on one side than the other. It was very subtle and not obvious, but noticeable if you looked. Hence there would be more wood to plane off one side than the other.

Even so I did protect the intake balsa with masking tape - a tip I picked up when building the JP.

Finally I assemble again. It is looking more and more like and A4.

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I fell asleep last night before I could finish posting and there is some gobbldigook in there - could some king moderator delete it as I have lost my ability to edit now.

Anyway i took a picture of the same sort of hole which Phil experienced. I too have glued some triangular stock into the hole. Like I said it was a problem one side but not the other - the side where the outside intake sheeting was set too low down at the back, thus exposing more side sheeting.

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Posted by Peter Garsden on 13/05/2016 21:27:01:

I have also sprayed the inside of the jet outlet fluorescent orange with an undercoat of white. I think it looks good. Am going to paint the outside silver.

Hmmm. Just googled a bit. As the J-52 installed in the Skyhawk has no afterburner (or reheat) and is mounted quite far forward in the fuselage (it is in fact above the wing) with a long jet pipe, probably the orange glow would not be visible at all. It does look good though.

Lorenz

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I decided to make a hole for the plastic wing bolt. I used my tried and tested tip of sharpening another same size wing bolt into a point then screwing in reverse way round with the tip sticking up, then forcing the wing onto the point to make a mark. Works well.

When I had done this I realised that I had put a 5mm blind nut instead of 6mm as intended, but no bother. The hole for the wing reinforcing plate will be too big but I am going to use a plastic washer to spread the load as well so no worries.

One can see that the wing load spreading ply plate will not sit flat because of the dihedral for the wing, hence I used a shim of 1/16" balsa to balance it up. Really it should be both side equally.

Edited By Peter Garsden on 26/05/2016 14:38:53

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Looking good Peter - yours must be fast approaching the final sand and covering stage - I need to play catch up as I've had a couple of weeks off mine, and next week I'm away in Devon so no building then either!! By my calculation its only 15 weeks until we meet on the Orme to test fly all these A-4 scooters!

That's only 105 days Matt - c'mon, crack on!

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I have bought, at great expense, some Fiskar Nail scissors to trim down canopies. Have had trouble with this before, but they are absolutely brilliant for the job.

I had some difficulty making the canopy fit at the rear - not the canopy dimensions, as they was exactly to the plan. I realised that I had not taken enough balsa from the top decking behind the cockpit, so I planed away. It still, at best, was only an edge fit, so I cut some 3mm square and stuck it on with super glue to provide extra support. This bit won't be seen anyway because it will be painted.

Canopy Supports


Canopy Skyhawk

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I nearly forgot the undercarriage outlines. I looked in the scrap box and had enough 1/2 inch for one but not the other, so I scraped together 2 pieces of 1/4 and a piece of 1/8. As one cannot buy 5/8"it has to be combined with 1/8" at least.

It was easier to use carbon paper to make a cardboard outline then glue the pieces together with clamps then plane to shape and sand. Then clamp to the underneath of the wing cos not quite flat

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Will I win the prize for 1st to finish I ask myself - getting quite near to finishing off, water based resin, and 25gram fibreglass cloth time and pilot painting - just not used to not be panicking at the last minute.

Have followed Phil's lead and used carbon rod control arms from a kit I bought a while ago from Irvine Engines. Apart from having to bore out the inner metal tube holders with a 3mm drill, it went together quite well.

Also not put together a 1 servo wing for many years - so much simpler, but don't think I will need spoilerons or flapperons on this one, judging by the way the Vulcan flies, and it is devilishly similar in shape.

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is that not just the effect of the wing wash-out when combined with straight aileron stock? I suspect we're all going to have this problem.

Could you not just paint the ailerons with ammonia (or vinegar in your case) and clamp both ends in line to the adjacent wing while it dries?

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Thanks Steve - that was my thought - will get out the vinegar and see what happens - good idea.

Well this afternoon I have been painting my little pilot I ordered from Real Model Pilots. I found a photo of an Israeli Pilot and copied him -

This is German Gunmetal grey from Tamiya paints. I have used Nato Green for his jacket, flesh for his face, and black for the visor and sun glasses and a white helmet. Next job is glue him into the cockpit as I have made a seat back for his head.

I made a little support from scrap and cryano'd him up there for intricate painting.

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Next job was draw the hump to be added to my version of the Skyhawk which is not shown on the plan. I took my 2D drawings and assessed the shape. I drew it freehand onto the plan, ready for transferring it with carbon paper to some cardboard templates (make sure you get the carbon paper the right way up or your efforts will be wasted?

I am going to make the hump out of blue foam by making templates for either side, then cutting off the excess with my handy Irwin Japanese reverse cut saw. It will be lighter and easier than balsa, and I can fill the foam with lightweight filler then light fibreglass cloth anyway.

 

Edited By Peter Garsden on 02/06/2016 09:45:16

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When I was looking at the 2D Drawings I realised that I had got the undercarriage housing completely the wrong shape. No wonder the wing felt heavy. I thought they were flat at the front and sloping towards the back. When I looked carefully they are tapered at the front and back. I planed off huge amounts with the David Plane and filed down with my fine Permagrit flat file, which worked a treat and took loads of unwanted weight off it.

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