Equivalent prop
03-26-2007, 12:02 PM
#1
Equivalent prop
Equivalent prop
My motor manufacturer suggests that it turn a GWS 860 propeller.
I just do not have that much clearance for on the intended model. I need something in the seven inch diameter range in order to fit and clear the gound.
Any idea as to an equivalent design? I have more than enough thrust, so can go smaller easily.
Later on this year, I have another one coming up. The motor manufacturer says to use a GWS 1043 propeller and again I need a more suitable one in the eight inch diameter range. Again, have more than enough thrust.
Wm.
My motor manufacturer suggests that it turn a GWS 860 propeller.
I just do not have that much clearance for on the intended model. I need something in the seven inch diameter range in order to fit and clear the gound.
Any idea as to an equivalent design? I have more than enough thrust, so can go smaller easily.
Later on this year, I have another one coming up. The motor manufacturer says to use a GWS 1043 propeller and again I need a more suitable one in the eight inch diameter range. Again, have more than enough thrust.
Wm.
03-27-2007, 10:04 PM
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RE: Equivalent prop
ORIGINAL: CoosBayLumber
The eight inch is expected to Max. at 14,000 RPM, but more likely use is at 12,000.
The ten inch is expected to Max. at 10,000 RPM, but more likely use is around 7,000.
Wm.
The eight inch is expected to Max. at 14,000 RPM, but more likely use is at 12,000.
The ten inch is expected to Max. at 10,000 RPM, but more likely use is around 7,000.
Wm.
If you go to a lower diameter prop, it has to spin faster to hit the same thrust as the prop you are replacing; pitch also enters into the equation - changing to a higher pitch prop at the same diameter will exert more load, so at the same power, it will turn lower rpms. The rpm figures look pretty high already, so a smaller one will push it perhaps beyond what's considered safe for the setup you have. A three blade might be an option but is less efficient than a two blade.
03-30-2007, 05:35 PM
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RE: Equivalent prop
Wm:
An equivalent prop might be another 8x6 prop by another manufacturer. You can get an equivalent load on your motor by changing propeller dimensions.
The load of an 8x6 prop on your motor is indicated by the amperes required with a given input voltage. So if the load is , say 10 amps, find a 7 inch prop with x pitch to give you 10 amps.
As a starting point, an inch drop in diameter should be accompanied with an inch increase in pitch for a near equivalent load; however, when you do find the pitch that gives you the equivalent load, you will find a different rpm and thrust. Less diameter gives higner rpm, while less pitch gives higher thrust.
feihu
An equivalent prop might be another 8x6 prop by another manufacturer. You can get an equivalent load on your motor by changing propeller dimensions.
The load of an 8x6 prop on your motor is indicated by the amperes required with a given input voltage. So if the load is , say 10 amps, find a 7 inch prop with x pitch to give you 10 amps.
As a starting point, an inch drop in diameter should be accompanied with an inch increase in pitch for a near equivalent load; however, when you do find the pitch that gives you the equivalent load, you will find a different rpm and thrust. Less diameter gives higner rpm, while less pitch gives higher thrust.
feihu
03-31-2007, 08:11 AM
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RE: Equivalent prop
ORIGINAL: CoosBayLumber
The eight inch is expected to Max. at 14,000 RPM, but more likely use is at 12,000.
The ten inch is expected to Max. at 10,000 RPM, but more likely use is around 7,000.
Wm.
The eight inch is expected to Max. at 14,000 RPM, but more likely use is at 12,000.
The ten inch is expected to Max. at 10,000 RPM, but more likely use is around 7,000.
Wm.
Prop Load Factor = diameter^3 x pitch
An 8x6 = 3072; an equivalent 7 inch would be 7x9, which I don't think exists. I would guess a 7x7 does exist - it will turn faster rpms than the 8x6 which may make up the power difference.
BTW: I hope these are not slo-fly props - your rpms are too high for them.
