504 Spitfire

[pedwards2932]

I am building the 504 Spitfire and have all the bones ready for covering. Total weight on the bones is 12 grams. I have seen that these tend to get heavy and will fly better the lighter I can make it. The tail feathers are pretty thing because I sanded the backside of the diecut sheets in order to get the parts out easily. They don't feel too flimsy but I think I am going to preshrink the tissue before I cover them. I could use a dremel and take some of the balsa out of the outside edge but I think this may make it even more flimsy. Is 12 grams pretty decent for the bones or should I try to lighten it even more?

[WIDDOG]

I don't know the answer to your question. I do know that on the 500 series kits the plastic and the clay balance weight adds up quickly. The 500 are kind of heavy I think because they are Multi Purpose kits. I think they fly kind of fast but do fly. This is kind of a older video. I have gotten better since than. https://youtu.be/aUMBwxJsBCo

I reviewed my notes on 500 series kits and what I have is 23 grams AUW is "Good" I think you can go up too 33 grams AUW. I will wait to see what the other members think.

[Coloradoken]

I am currently building a baby hornet which is a very lite flyer. The bare fuselage sans wings and tail came in at 23 grams uncovered so I think you are OK.

[David Lewis]

Using thinner balsa invites warps. Better to reduce the width of the tail outline pieces instead. Strength is directly proportional to the width of the member, but goes up as the square of the thickness. Sometimes the kit balsa is dense enough that you can sand it thinner and it will still be adequate, so that's a quick and easy way to reduce weight. The most effective way to increase strength-to-weight ratio is to use less dense balsa.

[pedwards2932]

I sanded the backside of the sheets to get the parts to release and did some more sanding to level out the pieces when assembled. I am going to preshrink the tissue on those parts. I may take some of the width out between the cross members as well.

[pedwards2932]

I have everything covered now with 2 coats of dope. I weighed all the pieces together (not assembled) and it came out to 28 grams. I am thinking about building the tail feathers using laminated strips and covering them to see how much weight I can save here. My thought is if I am real tail heavy this will reduce what I need to add to balance it. We will see how much difference it makes.

[twospruces]

When I built my 2 spitfires, I needed a lot of lead in the nose..seems I had to simulate a merlin.

The back end has to be really light!!! Starting from the cockpit aft.

[David Lewis]

The laminated tail outlines are stronger and lighter but it's more work than I'm willing to do. I like to keep the build as quick and easy as I can.

You can save weight by using Jap tissue instead of kit tissue, but whatever kind of tissue you use you will end up lighter by spraying it with 3M ScotchGuard rather than doping it. Also, 2 um thick mylar is 6 times lighter than Jap tissue (2 g/m^2 versus 12 g/m^2), and stronger as well.

[pedwards2932]

I already have it covered with some tissue I bought. We'll see how well it works. How are people balancing these planes....if you glue the front cowling on you can't add weight there so are you putting weight in the prop spinner?

[pedwards2932]

Well I rebuilt the rudder and elevator using laminated strips and it saved about 1.3 grams. I had to add about 3 grams nose weight to balance it. I glide tested and it seems to glide pretty decent maybe 30 or so feet starts to turn slightly to the right. After glide testing I added all the plastic pieces and I think this added about 1.5 grams. So all up weight is 32.5 grams. I want to do some powered testing before I paint it. Guess I'm going to have to try and build a new one and see how much I can lighten it.

[backyardbalsapilot]

32.5 grams is very good by my standards. What colors are you going to paint it? My spitfire came in at 50.3 grams, so I retired it to display life before flying it. I used kit wood and built it exactly to plan, so that had something to do with it. Also, because of the fuselage length (14" compared to a 16 1/2" wingspan) I added a lot of nose ballast. What sort of glue did you use? despite the 2 bottles of med. CA in the background, I used wood glue for this one.

[pedwards2932]

I used kit wood except for the tail feathers which I did using laminated 1/32 x 1/16 this seemed to save enough to decrease the amount of nose weight required but it still needed nose weight. I used Elmer's carpenters wood glue. I used toothpicks dipped in the glue to apply so I could use the minimum. I am going to try to paint it the same as it appears on the kit box. I am working on a winding stooge right now so I can do some testing before I paint it. I am also working on a way to cut out the parts for it using a craft cutter....so far I was able to successfully cut out the wing ribs.

[backyardbalsapilot]

For wood glue (titebond 1), I really like the Monoject syringe I have, though I do sometimes revert to the toothpick method. What sort of paint will you use/ will you use an airbrush? Also. am I alone in realizing that the 400 and 500 series spitfires have the same plane on the box? I like the idea of a winding stooge, but I typically employ the help of my brother to hold the rear peg. By a craft cutter, do you mean the kind meant for cutting out paper? That would be pretty cool.

[pedwards2932]

I will probably use water based acrylic and airbrush. I got a tripod at a thrift store for $1.99 to make the stooge just need to make a plate that will work to hold the plane. Yes it is a craft cutter...Sizzix Eclips. It will cut up to 1/16 balsa. I have been hesitant to post much on this forum about it but I have posted it at the hip pocket builders forum.

[MMitch2782]

Great job on your flying Spits. I used to fly em 2 but lately have turned to static builds that only get off the ground virtually.