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What prop?

pgerts

Old age member
Mentor
#2
Do you want maximum power?
What plane are you going to use the motor on?
The 8*4 might be the right prop for a 600 gram sport plane if you want best flight time.
A 9*6 might be right for another plane with more weight and more speed.
The only way to know exactly is to measure with the motor in the plane you are going to fly.
As they say 35A continously should not be any problem.
I guess that you will get about 16-18 A with an 8*4 depending on the plane and 3 cells.
 
#4
I know I should know this, but should I use a 8x4 prop for this 450 equivalent motor running at 1350kv?
http://www.altitudehobbies.com/brus...less-motor-peak-450-35-28-1500kv-suppo-2810-9
Thanks guys!
Get a watt meter (if you dont already have one!)

Buy a 8x4 3 blade or even 4 blade if you want big amounts of power. Note that your ESC must be upgraded and your motor must be able to handle the amount of watts or you will burn/fry the engine.

IMPORTANT:

Before mounting your engine to your fuselage screw it on a piece of medium sized triplex. Dont mount the prop on the engine before you do this step:
http://www.youtube.com/watch?v=_yLRGF5_4XU
after that balance your props and you can mount your engine to the plane! If you do this right you can get a vibration free plane.

EDIT:

You can also replace the servo tester with your radio, basicly the same thing!
 
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earthsciteach

Moderator
Moderator
#5
I *think* this is the same motor I used on my HZ Super Cub when I upgraded it to brushless and added ailerons. I'm pretty sure it is. The cub performed best on an 8x4e (thin) prop with that motor. I've since put a bigger motor on it because, well, why not? I'm not sure what an FPV Raptor is, so I can't make the comparison.
 

pgerts

Old age member
Mentor
#7
well, I'm using it on an FPV Raptor and it only has clearance for an 8x4 prop.
Not an 8*6 (or 8*8) then?
There is probably another way to get more power.
The specifications says 2-3 cells but i would have tried 4 cells.
On the other side - your plane wants more time in the air than speed.
 
#9
Just fit a huge battery in the raptor, get an 3blade or an 4blade bigger esc and you are ready to go.
Key to long durations flights:

Big battery (which almost fits)
Low KV motor (high watts and high max amps)
Biggest prop with most pitch/blades that you can find

I am also going to buy a 3blade 6x4 for my bixler.
 
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Carbon

Elemental Madness
#10
so I email Suppo and they said in broken engrish that an 8x6 prop running off of 3 cells would burn the motor up....it has to be able to swing a prop that size, the motor is pretty big...
 

Carbon

Elemental Madness
#12
yeah, I think something was lost in the translation. I was reading this post on RCgroups and decided to go with a 3 blade 8x6 pusher prop
 
#13
Size does not matter Ben! They can make a huge engine but that does not say anything about the performance!

Also they dont say anything about the max wattage that you can get with this motor. Maybe it would have been better if you had chosen an engine with a higher max wattage and a lower KV. Then you can use a prop with a higher pitch or a prop with more blades..
 

pgerts

Old age member
Mentor
#14
.....Also they dont say anything about the max wattage that you can get with this motor..
Was it not this motor?
Suppo 2810/9 (35-28) 1350kv Specifications:

  • Number of Cells: 2-3s lipo; 6-10 cell NiMh
  • Max Efficiency Current: 15-35A (75%)
  • No Load Current (10v): 2.1A
  • Max Current: 45A/60s
What more spec is needed?
11.1V*35A= almost 400W continously.
max 45A/60s ~ 500W
 

Carbon

Elemental Madness
#15
Yes, that is the one^
ok guys, remember, I'm still pretty new to this. I don't have a watt meter.
Can I just know, will a 3 bladed 8x6prop work with this motor and a 40amp speed control?
 

pgerts

Old age member
Mentor
#16
It will most likely work just fine but there is only one way to know for certain - measure.
The simple way is with an amp meter (current) in series (or clamp on) one of the cables from the battery to the Speed Controller.
Another way is to try. Give full throttle for 10 sekonds - stop and feel the temperature on the motor - IF OK then give 30 sekonds, stop and feel again. The motor should not get hot. Some heat is OK but not as hot as you will get burned when touching.
Compare with the other motors with similar specifications - 2810-9 and you will se that they use propellers up to 10*7 and the 8*6 3-blade is recommended for the polaris.
 
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#17
Yes, that is the one^
ok guys, remember, I'm still pretty new to this. I don't have a watt meter.
Can I just know, will a 3 bladed 8x6prop work with this motor and a 40amp speed control?
If a 8x6 prop will burn your motor as the suppo guys said dont use a 3 blade it will be even worse!! You can use an 100 amps esc but if your motor wont pull that much max amps or wat you will overheat it or burn it mid air. Imagine this happening 3km away or even further. My advice buy a lower kv motor (1000 kv) with a high max amps And a high max wattage big esc and them use the 3. Blade!!!