HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 19, 2014, 05:38 PM
Registered User
Ireland, Louth, Drogheda
Joined Jan 2014
8 Posts
Discussion
change of prop

Hi there,

Just wondering if I'm risking my electric setup with a new prop. The previous prop was a GWS 6x3.....I've replaced with a more durable looking Master Airscrew 6x3, 2 blade prop. It's run on a small10g brushless motor with a 6A ESC.
The master airscrew is nylon injected, hoping it will last longer than the GWS 6x3.

Haven't weighed them yet, but as a rough guess, would you think it's drawing more current on the new setup compared to the GWS 2 blade prop?

Thanks a lot!
Alan
Ps. don't have a power meter to compare the draw!
alanthorpe is offline Find More Posts by alanthorpe
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 19, 2014, 05:51 PM
Registered User
United States, CA, Fontana
Joined May 2011
992 Posts
Quote:
Originally Posted by alanthorpe View Post
Hi there,

Just wondering if I'm risking my electric setup with a new prop. The previous prop was a GWS 6x3.....I've replaced with a more durable looking Master Airscrew 6x3, 2 blade prop. It's run on a small10g brushless motor with a 6A ESC.
The master airscrew is nylon injected, hoping it will last longer than the GWS 6x3.

Haven't weighed them yet, but as a rough guess, would you think it's drawing more current on the new setup compared to the GWS 2 blade prop?

Thanks a lot!
Alan
Ps. don't have a power meter to compare the draw!
Probably OK, but i would buy a meter anyway.
Not that much money & a very important thing to have if you plan to stay in this hobby.
Clive66 is offline Find More Posts by Clive66
Reply With Quote
Old Aug 19, 2014, 05:58 PM
Registered User
Ireland, Louth, Drogheda
Joined Jan 2014
8 Posts
Quote:
Originally Posted by Clive66 View Post
Probably OK, but i would buy a meter anyway.
Not that much money & a very important thing to have if you plan to stay in this hobby.
Thanks a lot for that Clive, I'll buy one soon so and check it out!
alanthorpe is offline Find More Posts by alanthorpe
Reply With Quote
Old Aug 19, 2014, 06:15 PM
buyer of the farm
United States, FL, DeLand
Joined Mar 2009
4,417 Posts
Well, Alan, here's your comparison. The props are really quite similar. Here's the GWS with a randomly chosen 10g motor, 2S power supply and 10A ESC. We're talking 9737 RPM, 157 g static thrust, 6.9A current, 45 kph pitch speed and an efficiency of 6.3g/W for a projected full throttle flight duration of 5 minutes, 29 seconds.

And there's the same motor, battery and ESC with the MAS 6x3 prop.We get 9280 RPM at 167g static thrust, 42 kph pitch speed, 6.9A current, thrust efficiency 6.3g/W with a projected full throttle flight duration of 5 minutes, 9 seconds.

The Master Airscrew prop puts a little more load on the motor, reducing RPM and causing lowered flight duration. Other than that it's tomato, tomahto. For this particular motor the MAS loads the motor very slightly above rated capacity. Your motor will be different and only your wattmeter knows for sure.

In other words, relative numbers between the props will be valid, actual thrust, RPM, amp draw will be different for your motor.
Rockin Robbins is offline Find More Posts by Rockin Robbins
Reply With Quote
Old Aug 19, 2014, 06:27 PM
Registered User
Ireland, Louth, Drogheda
Joined Jan 2014
8 Posts
Quote:
Originally Posted by Rockin Robbins View Post
Well, Alan, here's your comparison. The props are really quite similar. Here's the GWS with a randomly chosen 10g motor, 2S power supply and 10A ESC. We're talking 9737 RPM, 157 g static thrust, 6.9A current, 45 kph pitch speed and an efficiency of 6.3g/W for a projected full throttle flight duration of 5 minutes, 29 seconds.

And there's the same motor, battery and ESC with the MAS 6x3 prop.We get 9280 RPM at 167g static thrust, 42 kph pitch speed, 6.9A current, thrust efficiency 6.3g/W with a projected full throttle flight duration of 5 minutes, 9 seconds.

The Master Airscrew prop puts a little more load on the motor, reducing RPM and causing lowered flight duration. Other than that it's tomato, tomahto. For this particular motor the MAS loads the motor very slightly above rated capacity. Your motor will be different and only your wattmeter knows for sure.

In other words, relative numbers between the props will be valid, actual thrust, RPM, amp draw will be different for your motor.
Hi Rockin Robbins, thanks a million for this, that's a great help! Thank very much! Tomahto, great stuff!!
alanthorpe is offline Find More Posts by alanthorpe
Reply With Quote
Old Aug 19, 2014, 08:16 PM
yank and bank!!
Joined May 2013
2,161 Posts
While it's unsettling to the how much GWS props can flex in my opinion... but I've found them to be more than reasonably durable.
failboat is offline Find More Posts by failboat
Reply With Quote
Old Aug 20, 2014, 08:10 AM
buyer of the farm
United States, FL, DeLand
Joined Mar 2009
4,417 Posts
When model airplane props were tested by the University of Illinois at Urbana-Champaign, Michael S Selig (you might be familiar with the Selig airfoils?), two manufacturers were singled out for making the worst propellers of all: GWS and Master Airscrew. With GWS, flexing and depitching at over 5k RPM and with MAS, terrible efficiency.
Rockin Robbins is offline Find More Posts by Rockin Robbins
Reply With Quote
Old Aug 20, 2014, 08:50 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,791 Posts
Quote:
Originally Posted by alanthorpe View Post
... Ps. don't have a power meter to compare the draw!
Will save you at least one fried motor and one fried controller Alan.
Go for APC electric props, assuming they are availabe in that size, higher efficiency.

Vriendelijke groeten Ron
Ron van Sommeren is offline Find More Posts by Ron van Sommeren
Reply With Quote
Old Aug 20, 2014, 10:38 AM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,272 Posts
The Master Airscrew props are often preferred by newbies because they break the other brands. But, they tend to have poor efficiency, though I doubt you'll notice that.
In a prop-strike kind of "bad landing" the force of the hit, especially if the stiffer prop is still turning aggressively (throttle still on) is transferred to the motor shaft, motor, and firewall, sometimes effectively doing even more damage than a broken prop.
flydiver is offline Find More Posts by flydiver
Reply With Quote
Old Aug 20, 2014, 12:23 PM
Registered User
Canada
Joined Nov 2000
7,071 Posts
Agreed...
GWS props are of Mickey Mouse appearance. MA's seem as more like real props.
However GWS are cheap, light and durable enough for their intended purposes
Efficiences could be better.. but it matters V little in these uses.
Apc props; Cuisinart blade things certainly look the business but are Extremely fragile things.
Their maker ' could' upgrade their resins to be less brittle ...but never has.
Much cheaper Hobby King sourced Clone Apc props are of better (more durable) material... If you must use that design.
Bare is offline Find More Posts by Bare
Reply With Quote
Old Aug 20, 2014, 12:33 PM
yank and bank!!
Joined May 2013
2,161 Posts
The GWS prop may depitch... but in static thrust tests they can produce decent thrust on smaller motors... in a surprising number of cases with less amps.
failboat is offline Find More Posts by failboat
Reply With Quote
Old Aug 20, 2014, 01:29 PM
Registered User
United States, CA, Fontana
Joined May 2011
992 Posts
On some applications, a GWS prop is the best way to go.
I have a Twisted Hobbies Crack Beaver & the GWS prop works best on that plane.
I also have other planes that a GWS prop was the way to go.
Clive66 is offline Find More Posts by Clive66
Reply With Quote
Old Aug 20, 2014, 02:09 PM
buyer of the farm
United States, FL, DeLand
Joined Mar 2009
4,417 Posts
So long as you keep RPM below 5500 GWS is okay. And to be fair, that is what they were designed for.
Rockin Robbins is offline Find More Posts by Rockin Robbins
Reply With Quote
Old Aug 20, 2014, 02:28 PM
Registered User
United States, CA, Fontana
Joined May 2011
992 Posts
Quote:
Originally Posted by Rockin Robbins View Post
So long as you keep RPM below 5500 GWS is okay. And to be fair, that is what they were designed for.

Are you refering to the GWS Slo Fly series props ?

I'm not an expert on this, but none of the motors i am using the GWS props on are below 5500 RPM, and they perform fine.
My Crack Beaver motor is a 1450kv running on a 3cell LIPO, so i'm guessing the RPM on that is probably around 12000.
Clive66 is offline Find More Posts by Clive66
Last edited by Clive66; Aug 20, 2014 at 03:08 PM.
Reply With Quote
Old Aug 20, 2014, 02:32 PM
25+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,465 Posts
EMP props are a good middle ground between the floppy GWS and stout MAS brands. Efficient and tough but still slightly flexible. I like 'em a lot. Have used the 6x3 and 6x4 varieties on several planes. Good prices too.

http://www.headsuphobby.com/EMP-6-x-...Prop-B-690.htm
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How often do you change props DCIV Multirotor Talk 4 Aug 14, 2014 07:56 PM
Discussion Super Cub prop change recommendations Chinthing Beginner Training Area (Aircraft-Electric) 3 Mar 28, 2014 10:45 PM
Discussion 4S vs 3S battery, do I need to change props or anything else? HoloPed Scratchbuilt Multirotors 1 Mar 23, 2014 10:28 AM
Discussion Changing Prop Rich__B Power Systems 5 Nov 15, 2013 01:50 AM
Changing prop size Frank B Power Systems 1 Sep 10, 2001 11:49 AM