Power Systems Talk about motors, ESC speed controllers, gear drives, propellers, power system simulators and all power system related topics

Multi Motor Brushed to Brushless Conversion- PBY

Old 07-04-2006, 06:43 AM
New Member
Thread Starter
Join Date: Mar 2006
Posts: 1
Default Multi Motor Brushed to Brushless Conversion- PBY

Working on a Multi-Engine upgrade from brushed power to brushless. Would prefer to go Outrunner direct drive vs Inrunner/Geared. Looking for motor size suggestions, recommended motors and any Motor/Esc combo ideas- know each motor requires a separate Esc.

Current flight performance is very good "scale". At a minimum want to try to maintain the same performance. Best scenario would be to gain some extra power/performance....but not looking specifically for increased flying speed. Prefer to stay in the 3S Lipo and/or 7-10 cell Nimah range for batteries.

Specs below....appreciate any comments.

PBY Flying Boat, Twin Engine----

Current power system:
2 ea Speed 400 motors
Scale 1:15.
Span 83 in.
Wing area 835 sq.in.
Length 52 in.
Weight with eight CP-1700 SCR nicads= 64 oz.
Wing loading 11 oz/sq.ft.
Two GWS geared motors E series with 3.4:1 reduction wired parallel driving APCe 9 X 6 props.
Static current is 18 amps, 9 amps to each motor, giving 26 ounces thrust. (Less thrust may be OK if pitch speed is higher, and I know there's a pay off between the two.)
Prop speed 5,200 RPM.
Average flight time is 15 minutes. (Flies 27 minutes on eight 3,000 mAH NiNH cells.
BeaverBob is offline  
Old 07-07-2006, 09:24 PM
Join Date: Jun 2006
Posts: 47


Two GBx doubles can replace your SP400s and let you lose that gearbox. I'll have to look up the wind count and gauge, but you'll be looking at ~ 20oz of thrust on 2s w/ a 11x4.7 GWS SF prop @ 9.5 amps, or 25oz of thrust on 3s w/ a 10x6 GWS HD prop @ 12.5 amps. Either way, you'll lose weight between the batteries as well. Motors will end up right around 42 grams a piece. AND technically if you go with the 2s setup you'll be able to run it all on a single ESC (no, each motors doesn't always have to run on its own dedicated controller if they're identical). Might have to use two tho depending on servo/bec load.

You said "static current is 18 amps, 9 to each motor for 26 oz thrust" total? This setup should net you 40-50oz of thrust and drop your weight. I know you're using 9x6s, so the bigger props may not fit with your scheme.
ScubaSteve is offline  
Old 07-21-2006, 03:45 PM
Join Date: Jun 2006
Posts: 47


Wondering how this project is going.

ScubaSteve is offline  
Related Topics
Thread Starter
Last Post
Power Systems
09-02-2008 01:37 AM
Seaplanes E-Powered
07-15-2008 03:57 PM
01-17-2008 04:03 PM
Power Systems
02-12-2007 10:03 PM
Power Systems
07-26-2006 03:50 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Quick Reply: Multi Motor Brushed to Brushless Conversion- PBY

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.11826 seconds with 13 queries