Can anyone who has used this motor give me suggestion on which 3 blade propeller size to start with for a Turnigy L5055A-400KV motor in a
Hangar 9 P-40B?

Turnigy L5055A-400 Brushless Outrunner 400kv
Specifications:
Dimension: 50mm x 55mm
Weight: 293g (with 4m connectors)
Kv: 400rpm/V
Voltage: 11.1v~29.6v (3s~8s)
Max Power: 1400w
Max Current: 55A
Max Efficiency: 80% @ 30A
No load Current: 1.4A
Internal Resistance: 0.30
Diameter of shaft: 6mm

Impossible to answer without knowing cellcount and battery size, etc. That in turn is not possible to know until you have set up the plane and determined CG etc., unless you have certain batteries lying around you want to use. Not like a glo engine where only certain props work. Suggest you familiarize yourself with a Propcalc such as Brantuas ezcalc motor calculator online which will give you a good place to start with the MAS 3-blades.

Warning with that motor: make sure you take the bell off and reglue the magnets. Many reports of failed motor because of this.

Also, if you have not bought the motor yet, I'd suggest a higher Kv of 600 for this application, so you can limit cellcount, but you really need to play with propcalc to figure out what's best for you. Note that the last choice in the ezcalc dropdown menus is "custom", which enables you to enter specific motor stats.

Originally Posted by TTRotary

Impossible to answer without knowing cellcount and battery size, etc. That in turn is not possible to know until you have set up the plane and determined CG etc., unless you have certain batteries lying around you want to use. Not like a glo engine where only certain props work. Suggest you familiarize yourself with a Propcalc such as Brantuas ezcalc motor calculator online which will give you a good place to start with the MAS 3-blades.

Warning with that motor: make sure you take the bell off and reglue the magnets. Many reports of failed motor because of this.

Also, if you have not bought the motor yet, I'd suggest a higher Kv of 600 for this application, so you can limit cellcount, but you really need to play with propcalc to figure out what's best for you. Note that the last choice in the ezcalc dropdown menus is "custom", which enables you to enter specific motor stats.

Thanks,
I hope this is enough information to help me with a starting point?
4S 4000. Might go to a 5S?
COG won't be an issue at all.
I have been using ecalc. I had to go custom. I have a rough idea. Not positive because that motor isn't listed and I don't know if the information I found on the motor is enough to give me an accurate reading.
My thought was the 400kv motor would allow me to swing a 15"x7"x3 or 15"x8"x3 on a 4S or 5S?

I have test a 5055-400 with a couple of 3-blade props. Here's what I got.

14x9-3 Master Airscrew:
5s 5000: 900+ watts @ 45 amps, 7300 Rpm
6s 5000: 1500 watts @ 65 amps, 8600 Rpm

15x13-3 APC:
4s, 5000: 900 watts @ 63 amps 5000Rpm
5s, 5000: 1240 watts @ 74 amps, 5500 Rpm

Originally Posted by tlh101

14x9-3 Master Airscrew:
5s 5000: 900+ watts @ 45 amps, 7300 Rpm
6s 5000: 1500 watts @ 65 amps, 8600 Rpm

Something wrong with this data.
Watts and amps indicate higher volts than stated.

14x9-3 Master Airscrew:
5s 5000: 900+ watts @ 45 amps, 7300 Rpm = 20V = 4V per cell
6s 5000: 1500 watts @ 65 amps, 8600 Rpm = 23.1V = 3.9V per cell

15x13-3 APC:
4s, 5000: 900 watts @ 63 amps 5000Rpm = 14.3V = 3.6V per cell
5s, 5000: 1240 watts @ 74 amps, 5500 Rpm = 16.8V = 3.4V per cell

The numbers look realistic enough to me, I don't like what the 15 x 13 x 3 is doing to the cell voltages but it might be OK if only used for short bursts.

Jack

Thanks guys.

I'm wondering if this motor will be any good on a 7.5lb plane on a 5s?

Which three blade prop size looks like it will give the best speed and thrust?
A 15" would work the best for the airframe.
What does a 15x10x3 look like?

I really want to run a three blade prop on the Hangar 9 P-40B.
But it's not looking very good.

Originally Posted by danpos

Thanks guys.

I'm wondering if this motor will be any good on a 7.5lb plane on a 5s?

Which three blade prop size looks like it will give the best speed and thrust?
A 15" would work the best for the airframe.
What does a 15x10x3 look like?

I really want to run a three blade prop on the Hangar 9 P-40B.
But it's not looking very good.

The 15 x 13 x 3 on 5S, at 1240 Watts, works out to 165 Watts per pound against the 7.5 lb. weight. And that should fly the plane well enough. But the performance would probably not be spectacular. If that 1240W was the full throttle peak reading the input power was 4.2W per gram of motor weight and that is probably OK for a momentary peak.

If you took off at that peak power and immediately throttled back to get the motor down into the 2.5-3 Watts per gram range it would probably be OK. I would also want a battery with a higher "C" rating to keep the cell voltages up around 4V or so at full throttle.

Here are some rules of thumb for power levels for various types of planes:

Approximate power requirements:

50-70 watts per pound; Minimum level of power for decent performance, park flyer/slow flyer models
70-90 watts per pound; Trainers and slow flying scale models
90-110 watts per pound; Sport aerobatic and fast flying scale models
110-130 watts per pound; Advanced aerobatic and high-speed models
130-150 watts per pound; Lightly loaded 3D models and ducted fans
150-200+ watts per pound; Unlimited performance 3D and aerobatic models

Jack

Thanks guys.
I appreciate the help.
That motor just isn't going to work.
I might put the L5055A-400KV in my FMS P47 1400mm?

I'm going to look at the G-60 motors instead.
Maybe a G-60 500KV on a MAS 15x7x3 on a 5s?
Looks like enough power and speed. Low flight times though. around 5 minutes?

I would like to run a 3 blade on this but not looking good.

I wouldn't give up on the prop until you see how it does in the air. I got all sorts of gloom and doom feedback when I proposed putting a 4-blade prop on my H9 Mustang 40. This was a Power 46 / 4S 5000 setup. It turns out that the plane flew very nicely. Of course, it was not as fast as the 2-blade, but it was also not that much slower. The multiblade props can always use more pitch, and they tend to unload more in the air. Also, the surfeit of thrust means the model will come closer to achieving the prop's pitch speed. You really have to consider all the variables here.

I have not flown with those 3 blade props, however I am running one of these motors in an old EZ Dago Red, on 5s, with a 14x12 prop. Fly it pretty hard for 6 min and batteries are right at 3.85- 3.9v per cell when I land. It's real fast too.

So it's done. Again...
Ordered the G60 500KV motor instead for the P-40B. I'll use the L5055A-400KV in another plane.
It looks like it will run great on a 5s.
I also ordered the 14x7x3 MAS prop to go with it.
I'll start with that.
With a 5s 5000 It shows a 10 minute mixed flying time. Hope that I get close to that.

Thanks for your help guys. Much appreciated.

So now that I have this motor without a home, what type of plane would this be best suited for? Any suggestions?
Something in balsa like a WWI plane ?

danpos I have no experience with the L5055 400 but I think it would fly that plane just fine. Have you thought about going to a higher cell count and a smaller prop? I think tlh's post was close to what would suit your needs you. From what I have seen when going from a 2 blade to a 3 blade just go down 1" in prop size per extra blade and test the amps.

I too would believe the 5055-400 would easily fly your plane on 5s with a 15/8/3 blade and handle a 14/9/3 on 6s using at least 30C batteries in the 4000mah range. For speed I'd use 6s. FWIW Doug B