Sunday, April 6, 2014
Posted with Blogsy
Must. Resist. Spending.
Weather sucks... Has for days. Already gusty outside, ground is soaked from torrential rains. Doesn't look good until Wed... Agita. Must. Fly. Something.
Friday, April 4, 2014
Sbach Power Calculations
I did some power calculations using 6S and various prop configurations using eCalc. I estimated the built up weight at 2500gms, and put what I think is my motor in the calculator (went back to do another 8S calculation and that motor choice was gone.... Odd). The simulations seem to make it clear that 6S will be more than powerful enough, giving in excess of a 2:1 thrust to weight ratio. Turns out 8S is likely to over amp the ESC and is waaaaay more power than it needs. It also is clear that I chose a good prop at 17x7 (though a 16x10 would give a nice increase in thrust I think is overkill). Guess I could have gotten a cheaper amp if I had done the calcs first, and not bought a HV ESC...Click the images to enlarge.
Power Setup:
Motor: Turnigy Aerodrive SK 5055-430kv
6S, 17x7, 60 amps, 1244 watts, 89.5% eff, 5497 gms thrust
6S, 16x10, 65 amps, 1346 watts, 89% eff, 6377 gms thrust
8S, 17x7, 94 amps, 2545 watts, 86.4% eff, 8819 gms thrust
"DANGER, DANGER, WIL ROBINSON!"
So it looks like my planned setup is a good one. Using about 130 watts per pound (aggressive aerobatic sport flying) at roughly 5.5 lbs gives a power requirement of 715 watts. I exceed that by a fair margin, say, about 42% more if I did my math right. Sweet! I will watt test the setup once I get it together, then see how she flies. I can move to a 16x10 if I want some more thrust and still stay within the power limits of the setup!
Thursday, April 3, 2014
Skyline/Goldwing Sbach 342 60"
Oh, I have been a very naughty boy...
Today I pulled the trigger on this gorgeous Skyline-Goldwing Sbach 342 60" (1520mm) from General Hobby. It was on sale, I had to! I am putting a Turnigy Aerodrive SK3 5055-430kv motor behind a HobbyWing FunFly 80A HV ESC, with Hitec HS-5485HB servos all around. I am planning on flying her 6-8S. I have a Spektrum AR610 DSMX reciever. I am planning to use an APC 17x7e prop. I suspect she will have plenty of power 6S but she can handle 8S.
She will be the highest powered plank I own. Build series to follow!
Monday, March 31, 2014
No Fly Zone
Well, it was a beautiful day, but super gusty with modrate sustained winds, so grounded. Kenny and I did meet up at MCRCC and spent a couple of hours chatting, and enjoying a cigar. It looks like stong winds are the story for the next few days... judgement rules, survive to fly another day.
Sunday, March 30, 2014
Pulse Preps
In hopes of breaking my flying hiatus tomorrow I cleaned up and setup my Hangar 9 Pulse 25XT. The cote had pulled a bit from previous tune ups, so I replaced some of it. I bought some Monokote at my LHS yesterday, but the yellow turned out to be transparent... happens to me a lot. So I used some Cubby Yellow I had brought with me. Redid the horizontal stab, and the underside of the left wing. Not too smooth a job... I ain't much for cote work, but she'll do!
Also recharging 4S batteries, and will later setup the flybarred 450 heli!
Okay, other than the color mismatch, it actually looks pretty good. The curve came out nice. I replaced the cote on the entire outboard edge as you can see, including the elevator.
Cote removed from the underside of the left wing.
White cote replaced, and first black stripe set in place.
All done. The outsermost stripe is a bit rough, I tuned it up better after the pic and it looks much smoother and tight. Finished up a couple minor cote touch ups on the fuse and now she is flight ready!
Tomorrow Kenny Chandler and I are planning to meet up at MCRCC Field in Gulfport and break my dry spell!
Subscribe to:
Posts
(
Atom
)