TOMMYSTA

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Hi guys,
I thought I'd like to share some pics and information about my winter project. I love to build planes out of foam, the wings, fuselage and tail section. I've built a large 100" span Spacewalker in the Scratch build forum along with a large 96" span Giant Slow Poke. Anyways I thought I would try a large AT6. I used some 3 views and came up with model that would span 96 inches, give me 1560 inches of wing area, use a 5 channel radio (the 4 flight functions + retracts). The target weight is 15-18 lbs which should give me an acceptable 22-28 oz wing loading. Keep in mind that this is a "sport scale" airplane. Some "liberties" were taken in the design phase for ease of construction, this plane will not and is not designed to win Top Gun!!! But you'll know what it is when you see it. I started this project after the 1st of the year and will post pics as it progresses.
THE WING
I started with the wing. I cut the 3 panels out of foam. The center section is part foam and part lite ply. You can see in the pics that the root ribs and the front landing gear section is made from ply. I used an aluminum channel for the outer panel spars. The outer wing panels were cut and a 1/4" slot was then cut using a template for the spar and glued into place. I had initially intended the outer panels to "plug" in, but on the prototype I've decided to make the wing a one piece wing. Hopefully the next ones to come along will have plug in wings. The outer panels were then sheeted and the foam area of the center section also. I ahd to make a wood plug for a plastic cover over the wheel well area on the center section. You can see pics of that also. I then glued the panels together and will wrap the joints with 6 oz fiberglass cloth and resin. The aileron servo pockets were cut out and holes bored for the servo leads through the wing panels and center section with an access hold in the middle of the wing center section...obviously this was done before the panels were glued together. The ailerons are to be hinged after I've glassed the surfaces. Balsa blocks were then shaped for the wingtips and attatched. Now the wing can be set aside and the fuse design and construction can begin.

TOMMYSTA

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Here are some more pics.

TOMMYSTA

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THE FUSELAGE
The fuse is designed in two halves..a right and a left. Each half is made up of 3 sections. You can see in the pics that the front two sections are cut from foam and glued together, and then a square box is cut out on the inside. The tail section is then cut out and also hollowed out to match the front two sections. Then they are glued together giving us a ompleted right and left fuselage side. I then taped them together and using templates I made I cut out the wing saddle, cockpit area and the rear tail section saddle area. The inside sides are then sheeted prior to joining the halves. Once joined the upper and lower areas are then sheeted. The inner bulkheads are then cut out and installed. Before the fire wall is installed the wing is layed into the wing saddle and the hold down dowel holes are drill through the wing saddle bulkhead and into the wing. The rear of the center section is then drilled and tapped for the 1/4 x 20 hold down bolts. Once this is completed the firewall can be installed and glued. I like to install the firewall prior to the outside sheeting. When I sheet the outer parts of the fuse i sheet right over the firewall giving it added strength. The cockpit area and the wing saddle are sheeted using 1/16th in balsa and sanded. I glued up 3 sheets of 1/16x6x48 inch balsa for each side and then sheeted the fuselage.
I will continue to post pics as it progresses, up next is the tail section......
Thanks for looking Tom

TOMMYSTA

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Here are some pics of the sheeted fuselage.
Tom

TOMMYSTA

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Here are son of the latest pics. Everyhting is going together great. As it sits the airframe weight thus far is 8 1/2 lbs. Now I need to start the cowl, make the plug, then the mold and then the actual part. i continue to post pics.
Thanks for looking.
Tom

MerlinL14

It is looking fantastic. I wish I had just 1/2 of your building skills.

JohnVH

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Wow, crafty

jeffk464

Very nice looking model, your technique looks like it works really well. I was thinking about making a foam core me 109 and am stuck a little bit on the technical aspects of it. Was planing on buying some foam from home depot and cutting out the profile of the fuselage on three panels glueing them together, then using a power sander to shape the fuselage until it looks right to me. After this I was going to fiberglass the outside of the fuse and then dig out areas on the inside for servos, reciever fuel tank and all that. I have tried this method before and had no trouble getting the foam into the shape I wanted, just not sure if it will be practical.

TOMMYSTA

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That procedure will work if you don't have a hot wire foam cutter. The only suggestion I would make is to maybe sheet the outer foam surfaces. I know you said you were going to fiberglass but I'm not sure a compression standpoint or from a rigid standpoint how just fiberglass would do. Depending on the density of the foam it may work just fine. Perhaps you could use some carbon fiber running the length of the fuse down both sides and that would certainly make it rigid.
I am also thinking about doing a 109 also using the same method I built the AT6. I was thinking around 80-84" wingspan and it should weigh less than 10 lbs w/o eng and radio.
Let me know if you need any assistance.
Tom

jeffk464

One question, what material do use to make the templates for your wire cutting work?

TOMMYSTA

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I use formica. Cut them on a scroll saw with a fine cutting blade about a 1/16" from the drawn line and then sand down to the line. I use 150 grit to sand them down and then 220 and 320 to finsih them off. And then every once in a while just prior to cutting some foam I will swipe them with 320 sandpaper just to give them a smooth surface and it seems to let the wire track more smoothly. I can't remember the last time I had to replace a formica template due to lots of use. I can get many, many cuts from my templates. I've had to replace some due to me banging them on the edge of the bench and nicking them up though.

jeffk464

Was curious on your progress. Do you have any more pictures or info, would like to know what your final weight is.