Electric Flight in Australia


Powerhouse by Kevin Johnson

Peter Pine
1/40 Kellehers Road
Pottsville Beach NSW 2489
Phone (02) 6676 1437
Mobile (0407) 732 440
E-mail: ppine@northnet.com.au 
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Kevin's Powerhouse specifications:
  • 2.1m wingspan
  • 2.5kg weight
  • Graupner 700BB neodyn motor
  • Graupner in-line Speed Gear 700 gearbox
  • 15 x 6 prop
  • 6,000 rpm on 8 cells
  • 8 - 12 cells
Powerhouse by Kevin Johnson
Most electric old timers are scaled down versions of the original, but not Kevin Jonson's Powerhouse! Kevin, who hails from Lismore on the NSW North Coast, built a full size model and finished it in "old worldie" sepia tones. It looks very authentic in the air, topped off by all the usual Old Timer trimmings, like Trexler pump-up airwheels.
For power Kevin turned to the very economical and under-rated Graupner 700BB Neodyn motor. Even the ferrite versions of these motors will give outstanding performance. The motor can be supplied with an in-line 2.7:1 Speed Gear gearbox fitted, and this is the unit that Kevin chose. This is not a planetary gearbox; instead it uses an idler shaft within the gearbox housing to transfer the thrust to a separate main output shaft which is mounted on twin ball-races. The idler shaft runs in twin needle roller bearings. Another alternative is the 2:1 belt-drive unit which accepts the 700 motors. I used one of these very effectively in a 4m wingspan glider where space was not an issue.
Kevin's Powerhouse flies very realistically on only 8 cells. It looks like a real Old timer climbing out slowly at a steep angle of attack. For more lively flying, Kevin changes to 12 cells.
Try a full sized Old Timer yourself. Electric power adds another dimension to this popular branch of our sport. Today the ready availability of low-cost outrunner motors and the success of LiPo batteries outdate Kevin's successful set-up - my suggestion would be either a Scorpion 3020-16 outrunner on 3S swinging a 14x7" prop for adequate power or a Scorpion 3026-10 on 3S with the same prop for more lively performance.