I'm gathering material to start this project sometime next year. Was wondering about the wing. It is already sheeted, does it have a spar running thru it. I like to do fast low fly-bys then pull up. Just want to make sure I dont fly beyond the structure design limits. Planning on a DL50.
Edwin

The wing comes pre-sheeted but no spar. A DA 50 shouldn't over stress the airframe.. The wing is glassed with heavier glass cloth out to the wheels and then lighter cloth after that. Just use the lighter cloth on the entire wing to get a smooth transition. It's an excellent flying plane..

Sounds like a plan. Thanks
Edwin

You will eventually over-stress the wing as designed. The glass layers on the bottom are not adequate to handle hard pullouts. I have stress cracks in the glass on both sides. I fixed them after about 100 flights with another layer of glass and re-painted the whole bottom. They showed up again. I am at 208 flights and have the cracks. I just pull up smooth and gentle now. The same cracks showed up on my son's Yellow Spit as well. It is a design issue. We are building another new spit now and have changed the whole front spar joiner to carry more load. It is a 1/8" ply spar that runs all the way through the center section and out past the gear mounts in the wing. Lightening holes applied in some areas. From 6 seasons of flying Yellow Spitfires I judge this as a required modification. Leo

Hi,

I use 2-oz cloth for the bottom of the wing. I overlap it from the tip to about 8 inches outboard of the joint, so that the entire center, plus 8 inches outboard on either side are glassed over with two layers of 2-ounce. Plenty.

Edwin,

I know how you fly. Put in the spar!!

Hey, I resemble that remark!! Hows it going, birdie?<g>

Thats what I needed to hear, some long term experience. I had planned on using some 4oz glass I have laying around. 8" past the joint sounds like a reasonable thing to do also. Is an 1/8" ply spar enough? I was thinking more along 3/16" or 1/4".
Edwin

Edwin,

All's well. We're running our scale meet this weekend. Flying the PT-19. Went up to Wenatchee WA for their Scale Master's Qual, and placed first in fun scale. Tim's about ready to shoot paint on his Mopevy. Once he's done with that project, it will be back on planes. I'm in the middle of a 1/5 109. I have a half built Vally Tempest for Tim to finish up when he's done with his car. Then there's the Ziroli Corsair kit and extra's I gave him, and I have an unstarted (except for the bubble canopy conversion) Yellow Spit. After that, who knows?

Know what you mean. Tim was pretty disturbed when that viper almost beat him. Whats he up to now, 650hp? That car was scary before he tore into it.

The yellow spit is a next year or two project. Gotta finish that busa 1/4 scale J3 and L4, then finish the TF P-47. The last struts I made for the P-47 didnt turn out so good so I set it aside for a bit. Got a GP Yak54 ready to play with and big sundancer bipe, those are for playing around with. ARCA done made me a CD, I do the warbird event now.
Edwin

Best of luck. Check with me before you get started on the Spit. Who knows, I might be willing to make you a deal if I haven't started back on mine by then.

Edwin, The 1/8" ply spar is plenty, but you need to understand that it stands the full height of the wing thickness. Much like those little ply joiner pieces they give you but all the way through the center section and much farther out into the wing. All the wing cracking occurs right up near the front and this is right where that original spar section goes through. See my highlighted photo of cracks on my wing. Put large lightening holes in the spar as it goes through the center section to save some weight. No hole at or near the intersection between the center and outer wing panels. Bond your spars, wing sections, and joiners with either Gorilla Glue or Elmers Pro-Bond Urethane adhesives. They are superior to epoxy on these foam/balsa/ply structures and the adhesive will foam up inside to fill voids and the lightening holes that you put in the ply. It is like riveting it to the foam. Cool stuff. Leo

Full height spars is pretty much a given, I agree. I would have expected the crack on the bottom, looks like it on the top. I have a lot of experience with probond and gorilla glue. Probond was used on a wing mfg P-38 foam wing sheeting years back, love that stuff. Gorilla glue was used to build my airplane trailer. I will probably do the spar fix early on. It doesnt sound like a big hassle. Just cut a slot, stuff it with spar, fill it with polyu glue. I learned that its much easier to wipe off the expanding glue as it happens within the first hour. The probond dried pretty hard and had to use the dremil to remove the excess.

Robert,
I already have the kit.
Edwin

That is the bottom in front of the gear mount. The structure you see on the left is the belly scoop. No cracks on top.

I apply masking tape over the balsa on both sides of the joint and then wipe off the excess against the tape. It makes clean-up so much easier plus you don't soak the balsa. Leo