|
|
|
|
|
|
|
|
|
I disagree. Many people run 6/3 to 6/4 props direct on a 400 with 7 cells and have no problems.It depends on cell # and type, as well as which motor you have. I run 5/5 APC's on 8 cells and don't cook motors, but I get them air too.
The formula is to multiply the ratio of the box X original pitch to get new pitch, and square root of the box to get new diameter and pull same amps as DD. TLH doesn't say which 400 he has.Could be a 4.8(hot) or 7.2-8.4(mild wind) motor, and this makes a huge diff. Agreed, keep them under 10 amps though. Also, prop selection depends on airframe type, smooth liking 1:1 dia/pitch, somewhat draggy liking 1.5:1, and draggy liking 2:1 diameter/pitch ratio. |
|
|
|
|
|
|
|
Good points. On a 6v 400 6x4 is doable on 7 cells, 6x3 is doable on 8.
More than that and its no real gain and short motor life. 400's seem to like volts, rather than curent, to do their best, and then require more gears. Anything less than 2:1 ratio rather indicates a warbird type plane than a slow floater. Probably 6x4 or 7x5 prop on those sorts of ratios. certain on 3s1p lipo a 6x4 and 2:1 box looks a very nice match. or 7x5 on 8 cells. That's the sort of thing I'd want to put in a 30" span warbird, and shoot for about a 16-18oz AUW. |
|
|
|
| Thread Tools | |
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Discussion 74" Grumman G-21 Goose for Geared Speed 400 | glue_sniffer | Scale Electric Planes | 421 | May 07, 2009 04:16 PM |
| Discussion 3 Bladed prop for geared speed 400 | ckjohnson | Power Systems | 5 | Feb 10, 2006 06:07 AM |
| folding prop for a geared speed 400? | exempt | Power Systems | 6 | Mar 27, 2004 06:21 PM |
| Need reco for brushless speed 400 motor for "Elipstik" 460 | neonbutterfly | Power Systems | 4 | Feb 28, 2003 01:34 PM |
| Help I need a good inline gearbox for my Speed 480 | Joe Elston | Electric Plane Talk | 6 | May 15, 2001 03:58 AM |