A flyer at the field gave me an XB-70 Valkyrie. An internet search leads me to think it is a HobbyKing model of 68mm rotor diameter with 3580Kv. I have 2 flights on her with 4S 2200 & 3300mah. I landed after only 2 minutes and both batteries were very hot and only 3% and 5% battery remaining on the 5 in 1 cell meter. Is something wrong? The batteries should not be that hot and like with all of my 64mm EDFs, there should be about 15% left after about 3 minutes flight time. The ESC is Turnigy 85amp. See 2 pics. Thanks.
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It is fairly well known that the Nicesky 70mm XB-70 (Hobbyking sold it, but did not manufacture it) has a very cheap EDF. Your story is common.
However, your model has an aftermarket RC Lander metal fan. I would do some research to find out the expected amp draw of that fan.
I have always felt that the inlet and exhaust ducting on the XB-70 might also cause the poor performance. Would be interesting to run your fan on a test stand and in the aircraft and take thrust and amp draw measurements for comparison.
For now, your best bet is to be very gentle on the throttle and cruise around slower and take it easier on the batteries. Battery cooling is also very poor on the stock model.
I know a number of folks have upgraded the fan and motor. My XB-70 is undergoing some repairs and it will get a better fan, motor and ESC before it flies again.
You might look around over on RCG and see how other owners have modified and improved the Nicesky XB-70.
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Thank you so much for all that info. cheap EDF? Funny just by the look of it, I thought the EDF was a good, well made piece of medal. What do I know! The specs on this RC Lander 70mm EDF says Max amps is 64a, Max Power is 1000w, Max volts is 14.8(4S). At least that’s what I found on an internet search. Maybe I’ll try replacing with another 70mm EDF and I’ll search RCG. Thanks again. I love the expertise on this site!Comment
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I said the stock fan was cheap, and then my next line stated you had a different fan, the RC Lander metal unit, which is not the stock fan.Originally posted by Pilotguy View Post
One other option would be to make room for a second 4S 2200 and run them in parallel, giving you a 4s 4400. I recall that one of two people added a new battery area behind the stock one, cutting into the fuse. The second battery was fairly close to the CG.Comment
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