Hyperion Sniper II -Need Help Building
I'll cut directly to the question for those who don't like to read.
How do ya build a light foamy?
I've got a Hyperion Sniper II ARF. It has a 39" (1000mm) wingspan. I need to build it LIGHT and it's my first time building a foamy.
Now for the 4 chapter book:
I've been flying and kit building since 1998. I'm not new to building kits and not new to 3D. I fly gasoline and electric. Gave up on glow years ago. I've built about 50 wood kits, some fiberglass cowls, and even a few imported Dutch kits from the 80's that I dug out of a trunk at a garage sale several years ago. But I've NEVER built my own foamy before. I've got foamies. But I've always bought them already assembled or used. I know I can build it. I'm not scared of that. What I am missing is the knowledge of you guys that have built 40 or 50 foamies.
I need to keep this plane LIGHT. That is my biggest concern. I'm flying at 6000' (1800m) and every bit of extra weight is going to cost me in performance. I've been flying at this altitude since 1998 and I know all about wing loading, trust me. You guys that fly at sea level are frickin' SPOILED!! ;)
So with that said, I've been doing my homework. I know it takes about 150-175 watts per pound to make me happy with a 3D plane.
Hyperion claims the plane will weigh 15oz (430g) RTF.
It has a wing area of 356sq.in (23dm sq.)
That puts the wing loading around 6.13oz per square foot. That would be nice and light.
The recommended motor puts out 280 watts. Thats nuts for a plane this size. The Hyperion motor is extremely powerful and light, but it's also $70 and grossly overpowered for this airplane. I've purchased a 20amp ESC and a 1000kv motor that should put out 200-210 watts with a 3S battery. It's 15g lighter than the Hyperion recommended ESC/motor combo.
I bought digital metal gear servos that exceed the recommended torque values by about 20%. The plane requires 4. I'm 2g heavy on each servo, so there's 8g of weight back.
Hyperion recommends 850-1300mah 3S batteries. I just happen to have a bunch of those exact 2 sizes on hand and they are all darn near new, so I'm planning to fly with the 850 3S first.
I'm flying FASST, and have purchased a Frysky 7ch RX that is compatible and fairly light.
What type of glue should I use? How do I install the CF reinforcements? How do I install the servos? How do I keep it LIGHT? I have no idea where to start. It's foam. It's totally foreign to me. :confused:
Thanks in advance for any help.
Hi Here are some glues that have been Tried and Tested on EPP foam, Some Great Reading too.
use Square CF tube for the wing Spar, the round CF tends to flex.
The best thing you can do is to over power your Plane and use a big prop at 6000'
Thanks Chellie. I've got Welders, Seal All and regular Goop. Looks like I'm in business.
Any tips for keeping it light?
As for the prop, given the thin air, I'll prop UP from where a guy at sea level is propped. If I flew this system at sea level, it should pull 20amps with a 10x4.7. From experience, I'll usually have to go up an inch in diameter to get the same amp draw at my altitude. Love my little watt meter. I always use it to tune and keep from cooking stuff.
200 watts should yank it around like a rag doll. I've got a 3.5lb plane with a 550-600 watt power system and it's blistering out of a hover.
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