HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 17, 2001, 03:12 AM
Registered User
Joined Oct 2001
4 Posts
how to tell if a motor can pull a certain plane

Without the help of motocalc, how do you tell if a motor (glow or electric) can pull a certain plane? Would you use static thrust measurements, rpm, etc?
bmess is offline Find More Posts by bmess
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 17, 2001, 03:43 AM
high-speed freak
opualuan's Avatar
San Jose, CA
Joined Sep 2001
3,863 Posts
imho, spend the money, buy motocalc. for example, the wes-technik dc5-2.4 with 8:1 gearing and 9x3 prop generates something like 60 g of thrust.


so, any plane under 120-150g should work, right? wrong. It's kinda hard to tell unless you have tons of experience estimating it (I DON'T, that's why i use motocalc). But, if your stall speed doesn't match the pitch and stalling characteristics, it doesn't work... so, that 9x3 setup really doesn't seem to work on anything faster than about 10-15mph. so, you better match the stall speed to your setup... I would buy motocalc...

no, I don't have any association with motocalc other than using it
opualuan is offline Find More Posts by opualuan
Reply With Quote
Old Oct 17, 2001, 03:55 AM
Registered User
Joined Oct 2001
4 Posts
I do own motocalc and it has helped me tremendously with electric power. However I am trying out glow power and I am back in the dark. I picked up the pattern in motocalc that bigger props with small pitch create more static thrust generally. As long as diameter to pitch is between 2:1 and 1.5:1 I think the plane should have enough forward speed to beat the stall speed. Glow engine manufacturers only recomend a few props so you are pretty limited and there is no gearing. Basically I need to find out how to measure static thrust and pitch speed like motocalc does. I just want to be in the general ballpark so that I know if my plane will maintain a reasonable speed and have good torque for its weight. Unfortuanately glow engine specs do not reveal any sort of thrust measurments or plane weight guidlines.
bmess is offline Find More Posts by bmess
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Axe EZ - How to Tell if Motor is Burned Out? Lon33 Coaxial Helicopters 6 Dec 28, 2007 02:30 AM
how to tell if Tango is 15k or30k rpm motor Konrad Kontronik 7 May 04, 2005 08:28 PM
how to tell if mybrushless motor is dying asjeep Power Systems 7 May 13, 2004 06:25 PM
How do you tell how many amps you can pull out of a li-poly battery? Kyle2baseball Batteries and Chargers 2 Feb 05, 2004 12:54 AM
how to tell if a motor can pull a certain plane bmess Electric Plane Talk 2 Oct 17, 2001 12:17 PM