glo prop on electric motors??

[hoosier37]

Master airscrew glo props

[Grasshopper]

Master Craft or Master Airscrew? I've tried a number of Master Airscrew props and haven't had much luck with them. The APC electric props are generally more efficient.

[kyleservicetech]

Originally Posted by hoosier37

Master craft glo porps

Another vote for the APC-E electric props. They are more efficient, AND they will often break before bending up the motor shaft on those other than perfect landings.

[Lieutenant Loughead]

I've used Master Airscrew props on my GWS airplanes -- they're great props, but they're stiff and make belly landings a bit challenging.

However, my longest recorded flight was 52 minutes on my GWS Zero with a Master Airscrew 9x7 3-blade prop. It is amazing how much lower the amp draw is with a Master Airscrew prop than a GWS prop, or an APC-E prop. (Don't believe me? Try it and see!)

Actually, now that I think about it, I *currently* have a Master Airscrew 9x7 3-blade prop on my custom-built Aerial Photography platform (which is NOT a belly lander).

I highly recommend Master Airscrew props. If you are going to belly land, use a GWS prop.

APC props are nice, but I tend to break them easily on belly landings (especially the APC 8x8 props, for some strange reason)...

Oh -- and I have NEVER bent a prop shaft while using a Master Airscrew prop.

[CHELLIE]

I use Master airscrew glow props on larger e motors, they work great, they are a little heavier than a e prop, but they work well and are very strong. just my 2 cents worth Take care, Chellie

[Grasshopper]

Originally Posted by Lieutenant Loughead

I've used Master Airscrew props on my GWS airplanes -- they're great props, but they're stiff and make belly landings a bit challenging.

However, my longest recorded flight was 52 minutes on my GWS Zero with a Master Airscrew 9x7 3-blade prop. It is amazing how much lower the amp draw is with a Master Airscrew prop than a GWS prop, or an APC-E prop. (Don't believe me? Try it and see!)

Actually, now that I think about it, I *currently* have a Master Airscrew 9x7 3-blade prop on my custom-built Aerial Photography platform (which is NOT a belly lander).

I highly recommend Master Airscrew props. If you are going to belly land, use a GWS prop.

APC props are nice, but I tend to break them easily on belly landings (especially the APC 8x8 props, for some strange reason)...

Oh -- and I have NEVER bent a prop shaft while using a Master Airscrew prop.

I've had the exact opposite results. I haven't tried a lot of Master Airscrew props, but the few I have tried always drew more amps than the coresponding APC E props. Guess it all depends on the set up.

[CHELLIE]

Originally Posted by Grasshopper

I've had the exact opposite results. I haven't tried a lot of Master Airscrew props, but the few I have tried always drew more amps than the coresponding APC E props. Guess it all depends on the set up.

Hi Tom Yes your right, it depends on the set up, I use the Master Airscrew props on motors that are about 1000KV any higher KV than that, and they will draw more amps as compaired to a E Prop.

[Dr Kiwi]

It depends on exactly which MAS props one is using... the "Master Airscrew Electric Only" suck amps and are hopelessly inefficient. The "Master Airscrew GF/3" are fairly close to APC E in terms of amp draw/efficiency. There are lots of other varieties of MAS props... and each will be different....I have not tried the larger 3-bladers.

[Grasshopper]

Originally Posted by Dr Kiwi

It depends on exactly which MAS props one is using... the "Master Airscrew Electric Only" suck amps and are hopelessly inefficient. The "Master Airscrew GF/3" are fairly close to APC E in terms of amp draw/efficiency. There are lots of other varieties of MAS props... and each will be different....I have not tried the larger 3-bladers.

That's exactly the experience I had with MAS E props. Mine were all in the 8" to 11" size.

[Lieutenant Loughead]

Well, my experience differs. Mine was a 9x7 three blade. I've also used a 10x7 two blade, and the amp draw was lower than the corresponding APC-E prop.

I was (and still am) using a Himax 2025-4200 (4200 kv) with a 5.67:1 gear box.

If interested, I can give you the exact amp draw measurements when I get home tonight.

[BEAR-AvHistory]

I use MAS 3 blade & Hobby King Cherry wood props with good results on larger motors.

[rcers]

Add me to the list of MAS haters. All I have run are horribly inefficient. They suck amps and don't give much thrust in return.

I avoid them like the plague.

I have had much better luck with APC-e props for higher power systems and LOVE the GWS HD props for lower power systems (under 300w).

I am new to the Turnigy light electric wood props but may be starting to like them best of all.

I have used APC glow props in a number of cases with great results too. I use them especially when I need square or over-square props for fast planes.

Mike

[Larry3215]

Originally Posted by Lieutenant Loughead

Well, my experience differs. Mine was a 9x7 three blade. I've also used a 10x7 two blade, and the amp draw was lower than the corresponding APC-E prop.

I was (and still am) using a Himax 2025-4200 (4200 kv) with a 5.67:1 gear box.

If interested, I can give you the exact amp draw measurements when I get home tonight.

Amp draw alone isnt enough data to let you know if one prop is "better" than another one.

You need to compare the amp draw and the rpm and the thrust your getting. Preferably in the air, but bench testing is the next best thing.

Sometimes a lower amp draw is a good sign and sometimes its not so good.

The thrust your prop produces is a better measure of how much work its doing as opposed to how much heat is being produced.

In other words, are those amps going into heating your motor or making noise or are they actually going into moving the plane forward.

Thats not always an easy thing to compare if the numbers are close.

One prop may be drawing fewer amps but at the same time producing less thrust than a second prop.

Is it "better" or more efficient than the second prop? You dont know unless you take a closer look at exactly how much less thrust for the lower amp draw.

If it was drawing fewer amps and producing more thrust, the answer would be pretty clear that its a better prop, but its not always that easy.

The prop thats drawing more amps may also be producing enough extra thrust to more than justify those extra amps.

Im tired and on pain pills so my mind has gone fuzy and I cant recall off hand if thrust varies as the 2nd, 3rd or 4th power of the power to the prop.

You need to know that formula to calculate if the difference in thrust between two props is justified by the difference in amp draw.

In other words, if you double the power being fed into a prop do you get 25% more thrust or 33% more thrust or 50%? I cant recall at the moment.

What Im leading up to here is that small changes in the thrust produced by the prop are far more important than small changes in the amp draw as far as efficiency goes, BUT you need to take BOTH into account.

[Larry3215]

Nope - I was wrong - I am fuzzy! The relationship of amp draw to thrust is close to linear and not exponential.

In theory, the amount of thrust a prop produces should change more or less in direct proportion to the amp draw. Not exactly but pretty close. Thats ignoring things like the change in motor efficiency with amp draw - which may be significant.

So, say you have two props and one is drawing 10 amps and producing say 20 oz of thrust.

If another prop is drawing 5 amps and its producing 10 oz of thrust its exactly equal in efficiency.

If prop A is drawing 10 amps and 20 oz of thrust and prop B is drawing 8 amps at 16 oz of thrust they are also both equally efficient at converting electrons to thrust.

In other words, a 10% change in amps from one prop to another should equal a 10% change in thrust between the two - all other factors being equal. If the difference in amp draw vrs in thrust isnt in proportion, then the props are not equally efficient.

Irregardless of efficiency, one prop may still be "better" for your style of flying even if its less efficient - ie you may want longer flight times and are willing to trade off lower thrust to get it.

[Larry3215]

Too answer the original question - it depends

Some glow props from some mfg's are very efficienct compared to similar APC E props or to other brands.

I havent found one brand to always be "best".

Some APC props are great and others not so great. Same with GWS and other brands. I have to say though that the few MAS props Ive played with fared poorly.

Generally speaking, the hi end carbon props are generally pretty good when compared to plastic or wood props - but again not always.

The only way to know for sure is run some tests and compare amp draw vrs thrust and see for yourself.

[Lieutenant Loughead]

LOL -- sorry I wasn't more clear earlier, Larry.

The data I have collected on Master Airscrew propellers versus APC and GWS propellers has been on a thrust bench and a torque bench (to measure efficiency).

The following data was taken from a Himax 2025-4200 (4200 kv) brushless inrunner motor with a Cobri 5.67:1 gearbox, and a 3s 2100 mAh LiPo:

Master Airscrew 10x7 propeller
11.02 peak amps
10.26 minimum volts
114.0 peak watts
23.6 ounces of thrust
6690 RPM
44.35 MPH of prop pitch speed (based on measured RPM)

Master Airscrew 9x7 3-blade propeller
xxx peak amps (somehow I've lost this data)
xxx minimum volts (somehow I've lost this data)
109.2 peak watts
18.8 ounces of thrust
xxxxx RPM (somehow I've lost this data)
45.10 MPH of prop pitch speed (based on measured RPM)

APC 10x7E propeller
14.68 peak amps
10.69 minium volts
157.6 peak watts
29.3 ounces of thrust
7140 RPM
47.33 MPH of prop pitch speed (based on measured RPM)

GWS 10x6 3-blade propeller
15.76 peak amps
11.77 minimum volts
188.0 peak watts (exceeds motor specs)
34.6 ounces of thrust
7400 RPM
42.05 MPH of prop pitch speed (based on measured RPM)

Based on the above data, I believe the MAS props work well, and provide LOWER AMP DRAW, which result in LONGER FLIGHTS. (Again, my flight record was 52 minutes with a MAS 3-blade prop on a GWS Zero -- can you beat that?!)

I'll see if I can REcollect the MAS 9x7x3 data this weekend -- I currently have that power system installed on my aerial photography platform.

I believe that most people can't (or won't) back up their statements with actual lab-collected data -- their statements are based on an emotional response.

[rcers]

Originally Posted by Lieutenant Loughead

I believe that most people can't (or won't) back up their statements with actual lab-collected data -- their statements are based on an emotional response.

While I do static test all my systems it is one measure of performance. In the air is where it matters.

I will just give one example:

Setup was on my e-Flite Beaver
I really wanted to use a 3 blade prop for looks...

My static results were as follows:

MAS Propeller	Amps	Watts	Voltage
11x7x3	43	655	14.8v

That same motor and battery did the following again static with 2 blade various props:

Propeller	Amps	Watts	Voltage	RPM
APC-e 11x7	37	560	15.2v	9,500
APC-e 11x8.5	40.4	598	14.8	9,300
APC-e 12x6	38	558	15	9,100
Trunigy Light Electric 12x6	38.6	560	15	9,100

What is important is the APCe 12x6 and Turnigy Props both pulled the plane better in the air. This is while produce FAR less power consumed (100w static).

So the Beaver flew better with those props and the 13x6.5 prop in the air. Takeoff rolls were shorter, power in aerobatics (not something the Beaver was great at...) was better and my flights were longer.

Why did I fly the Beaver with a 3 blade prop when it didn't perform better? Simple it looked better and had an abundance of power, since the funnest thing to do with the Beaver was low and slow with the flaps down touch and go's.

My in flight and static results with other MAS props both 2 and 3 blade are similar to this experience.

Most of us don't just pull this out of thin air. We really do test and care about what we recommend to others. I fully comfortably stand by my real life experience of MAS propellers, they stink.

So, there you go - real live data.

Mike

[kyleservicetech]

[QUOTE=Lieutenant Loughead;793522]LOL -- sorry I wasn't more clear earlier, Larry.

The data I have collected on Master Airscrew propellers versus APC and GWS propellers has been on a thrust bench and a torque bench (to measure efficiency).

The following data was taken from a Himax 2025-4200 (4200 kv) brushless inrunner motor with a Cobri 5.67:1 gearbox, and a 3s 2100 mAh LiPo:

[QUOTE]

Ah Ha!

The prop pitch air speed in your results is important, doesn't do much good for a prop to put out a lot of thrust, if the prop pitch airspeed is so low that it won't get the model off of the ground.

[Lieutenant Loughead]

Originally Posted by rcers

I fully comfortably stand by my real life experience of MAS propellers, they stink.

LOL -- it must not have been so bad -- you used it anyway!

My example is a 3s LiPo -- yours is a 4s LiPo. Perhaps that makes a difference in our results?

Maybe it is the motor choice?

What is the original poster flying?

Originally Posted by kyleservicetech

Ah Ha!

The prop pitch air speed in your results is important, doesn't do much good for a prop to put out a lot of thrust, if the prop pitch airspeed is so low that it won't get the model off of the ground.
[/INDENT]

You've lost me -- the prop pitch speed in all my data is very similar. What is vastly different is the amp draw.

My advice to the original poster is to test it yourself and make your own decision. Obviously, everyone here has a different opinion.

[hoosier37]

Originally Posted by Lieutenant Loughead

LOL -- it must not have been so bad -- you used it anyway!

My example is a 3s LiPo -- yours is a 4s LiPo. Perhaps that makes a difference in our results?

Maybe it is the motor choice?

What is the original poster flying?

You've lost me -- the prop pitch speed in all my data is very similar. What is vastly different is the amp draw.

My advice to the original poster is to test it yourself and make your own decision. Obviously, everyone here has a different opinion.

Your advice will be taken. I can see differences of opinion but that is good and I appreciate everyones thoughts and research. Guess I will start by buying a wattmeter. Thanks again!

[kyleservicetech]

[QUOTE=Lieutenant Loughead;793577
You've lost me -- the prop pitch speed in all my data is very similar. What is vastly different is the amp draw.
[/QUOTE]

Sorry, I didn't make my self clear, so often people list the propeller thrust only, as if that is all that is important for a given propeller/motor/battery setup.

Your data INCLUDED the prop pitch speed, which is the last part of the required information to make the data useable. (And that's a good thing!)

After all, someone could take a little motor, put a gear box on it, turn a 20 inch prop with gobs of thrust. But if that prop pitch speed is only 15 MPH, that won't work on a model that flys at 40 MPH.

[Larry3215]

Originally Posted by Lieutenant Loughead

LOL -- sorry I wasn't more clear earlier, Larry.

The data I have collected on Master Airscrew propellers versus APC and GWS propellers has been on a thrust bench and a torque bench (to measure efficiency).

The following data was taken from a Himax 2025-4200 (4200 kv) brushless inrunner motor with a Cobri 5.67:1 gearbox, and a 3s 2100 mAh LiPo:

Master Airscrew 10x7 propeller
11.02 peak amps
10.26 minimum volts
114.0 peak watts
23.6 ounces of thrust
6690 RPM
44.35 MPH of prop pitch speed (based on measured RPM)

Master Airscrew 9x7 3-blade propeller
xxx peak amps (somehow I've lost this data)
xxx minimum volts (somehow I've lost this data)
109.2 peak watts
18.8 ounces of thrust
xxxxx RPM (somehow I've lost this data)
45.10 MPH of prop pitch speed (based on measured RPM)

APC 10x7E propeller
14.68 peak amps
10.69 minium volts
157.6 peak watts
29.3 ounces of thrust
7140 RPM
47.33 MPH of prop pitch speed (based on measured RPM)

GWS 10x6 3-blade propeller
15.76 peak amps
11.77 minimum volts
188.0 peak watts (exceeds motor specs)
34.6 ounces of thrust
7400 RPM
42.05 MPH of prop pitch speed (based on measured RPM)

Based on the above data, I believe the MAS props work well, and provide LOWER AMP DRAW, which result in LONGER FLIGHTS. (Again, my flight record was 52 minutes with a MAS 3-blade prop on a GWS Zero -- can you beat that?!)

I'll see if I can REcollect the MAS 9x7x3 data this weekend -- I currently have that power system installed on my aerial photography platform.

I believe that most people can't (or won't) back up their statements with actual lab-collected data -- their statements are based on an emotional response.

I had forgotten you are one of the (very) few who document flight data so well

I test virtually every setup I do with multiple options but Im terrible about writing down the data where I can find it later. That often forces me to repeat testing but I dont mind that much

***********Oops - I am still on drugs and made a false assumption when I ran those numbers the first time - so ignore my earlier findings I'll re-do those calcs in a while *****

I have to ask though - were those all three run on the same exact motor, esc and battery pack? The battery pack is not as big a deal as the motor/esc being the same and the esc programming being the same.

If not, then the data is not valid for comparing the props. Variations in motor/esc efficiencies could easily mask prop differences.

Im asking because in the MAS test the voltage under load was a lot lower than the APC test even though the load itself was also lower. If they were identical power systems the voltage should have held higher at the lower load. Based on the current and voltage data it looks to me like 3 different motors were used?

The GWS setup held voltage best under the highest load - and it was the most efficient system tested - but was that due to the motor/esc or the prop?

[Larry3215]

Denny - those prop pitch speed numbers were calculated - not measured.

They are only valid IF you trust the pitch number as given by the mfg of the prop.

You're right that pitch speed would normally be an important factor in comparing props. However, many people have measured actual pitch numbers of props over the years and most are only vaguely in the ball park.

Thats especially true of the GWS props. They flatten out so much under load the numbers they give are meaningless. Plus they vary a lot from one prop to the next - a problem all plastic props seem to have to one degree or another.

Actually, in flight airspeed would be the better data point to use. Thats very difficult to get accurately though. And again, it would only be valid IF the exact same plane and power system were used.

A better number to get and use for comparison on LL's dyno machine might be the airspeed of the slip stream. But again, thats really tricky to measure reliably and consistently from one prop to the next.

I think the raw thrust number is probably the only data point that can be easily and consistently measured with any accuracy.

[Larry3215]

oops - just realized I screwed up big time in my calcs above. I edited the above post. I'll re-do the math when my brain is working again

[kyleservicetech]

Originally Posted by Larry3215

Denny - those prop pitch speed numbers were calculated - not measured.

They are only valid IF you trust the pitch number as given by the mfg of the prop.

You're right that pitch speed would normally be an important factor in comparing props. However, many people have measured actual pitch numbers of props over the years and most are only vaguely in the ball park.

Thats especially true of the GWS props. They flatten out so much under load the numbers they give are meaningless. Plus they vary a lot from one prop to the next - a problem all plastic props seem to have to one degree or another.
.

Yup, programs such as www.motocalc.com provide calculated values of the pitch speed. Don't know how you'd measure it though. Even putting a "wind meter" in the prop slip stream will vary all over the map, depending on whether you've got the wind meter near the edge of the prop, or closer to the hub.

But, as you've noted, the prop wind speed is an indication, and it's useful, only if you know what its limitations are.

And, I've used those plastic props on models on the order of about 100 watts. They are so flexible I've heard them go into flutter just powering the motor up. They do make good paint stirring sticks though. As long as you don't use them on house paint. they will just bend all over the place.