Hey guys, thanks for the ideas.
Bob, I have used foam board before but not for any jet stuff. Im a little afraid of the heat in the rear for it. However it may be just the ticket for the vertical fin. I'll have to check it out. What is the difference between Gator Board and regular foam board?
Matt, Vacuum lamination of the fuse sides before building was what I was thinking of. I was wondering why you use larger weave and heavier weight cloth on the outside vs inside. I wanted to skin the whole thing with .7 oz cloth for finishing so wonder if the large 3 oz weave would be harder to fill and paint. Also I was going to make the doublers and formers from the same material as the fuse sides. I would just cut out the doublers and formers from pre laminated planks. Then I could bag the larger fuse side and doublers at the same time under the glass on the inside. It seems this would be very strong. I was thinking of running some 1" uni-carbon tape on the top and bottom of the fuse sides but not sure if this would produce any extra strength.
Your wing skinning and tube joiner ideas are similar to what I was going to use. I like the idea of putting the glass on the foam over and under the end of the wing tube to spread out the stress at the tube socket end. I was planning 1/8" wing skins but based on your suggestions I may go back to 3/32". Also I was wondering if glassing the inside of the skins was worth it. .7oz was my thought. Would carbon veil be better? If so how does it ad to the strength. It seems that the carbon fibers are short and run in all directions from what I have used. How does it work on the inside of the wing skin?
I was interested in how you use carbon tubes for longhorns. What size tubes do you use for this size fuse? Also not shown in the Lancer photo above, the Sabre will have NACA air inlets behind the wing TE to get air inside to the engine. See attached photo below for similar intake. This will leave just a narrow area of the fuse sides above and below the widest part of the inlet hole to hold the entire back end on with the weight of the engine and TV nozzle. I wanted to use some kind of carbon in these narrow areas to make sure the back end does not fall off under G load or hard landing. Any suggestions there?
I hope to start construction in late fall for next spring test flights. I still have some time to decide how to build the thing. I have the retracts, fuel/smoke tanks, canopy, wing tubes and sleeves, and Kingtech 180G engine on hand so far. I still need to get wood, glass, and foam. My questions and you guys suggestions are helping me understand what type and how much glass cloth I need to get.
I came up with 19-25 oz/sq ft using the same numbers, 3600 sq in or 25 sq ft. Still very light for this size wing. My experience says speed will be somewhat higher, however it will not be fast, which is what I want. A slow jet. I have been flying my AcroJet since 2003 and have never seen it above 130mph. It is an IMAC jet, built from an old Aeroworks G-202 foam wing and tail, fixed gear, and light ply and balsa fuse with external engine between the tails . Span 104" and weight 31lbs empty 41lbs full fuel and smoke with 34 lbs of thrust. After 8-10 min of aerobatics I download an average 65-85mph with a max of 100-110mph nearly every fight. I feel I could easily snap or bend the 1 1/2" aluminum spar tube if I yanked it when going fast. That is why I planned on using 2 x 2" tubes on the Sabre XLT since it can generate a very fast turn rate. The Sabre will also have retracts so will not have the fixed gear drag. I will try to attach some AcroJet photos. Thrust vectoring at post stall airspeed is really fun and with smoke on makes some cool smoke patterns.
