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These are the results for a 3 cell battery with a 9x5 APC-E prop

Battery
Load: 9.39 C
Voltage: 10.73 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 5.4 min
Mixed Flight Time: 9.4 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 15.02 A
Voltage: 10.73 V
Power: 161.2 W
  Motor @ Maximum
Current: 15.02 A
Voltage: 10.64 V
Revolutions*: 9385 rpm
electric Power: 159.9 W
mech. Power: 122.9 W
Efficiency: 76.8 %
est. Temperature: 48 °C
  118 °F
 
Thermal Curve
3 7 15 23 s
35 40 45 47 °C
94 104 113 117 °F
  Propeller
Static Thrust: 901 g
  31.8 oz
Revolutions*: 9385 rpm
Stall Thrust: - g
  - oz
avail.Thrust @ 0 km/h: 901 g
avail.Thrust @ 0 mph: 31.8 oz
Pitch Speed: 72 km/h
  45 mph
Tip Speed: 404 km/h
  251 mph
specific Thrust: 5.63 g/W
  0.2 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 208 W/kg
  94 W/lb
Thrust-Weight: 1.13 : 1
Current @ max: 15.02 A
P(in) @ max: 166.7 W
P(out) @ max: 122.9 W
Efficiency @ max: 73.7 %
Torque: 0.13 Nm
  0.1 lbf.ft
Climb Capacity: 2447 m
  8028 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 72 km/h
  45 mph
est. Speed (vertical): 10 km/h
  6 mph
est. rate of climb: 7.5 m/s
( ~45...50° ) 1478

ft/min

 

 

And the results for a 10x6 APC-E prop 

Battery
Load: 13.31 C
Voltage: 10.58 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 3.8 min
Mixed Flight Time: 7.9 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 21.29 A
Voltage: 10.58 V
Power: 225.2 W
  Motor @ Maximum
Current: 21.29 A
Voltage: 10.45 V
Revolutions*: 8358 rpm
electric Power: 222.6 W
mech. Power: 159.0 W
Efficiency: 71.4 %
est. Temperature: 64 °C
  147 °F
 
Thermal Curve
3 7 15 23 s
41 50 59 63 °C
105 122 138 144 °F
  Propeller
Static Thrust: 1176 g
  41.5 oz
Revolutions*: 8358 rpm
Stall Thrust: - g
  - oz
avail.Thrust @ 0 km/h: 1176 g
avail.Thrust @ 0 mph: 41.5 oz
Pitch Speed: 76 km/h
  47 mph
Tip Speed: 400 km/h
  248 mph
specific Thrust: 5.28 g/W
  0.19 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 295 W/kg
  134 W/lb
Thrust-Weight: 1.47 : 1
Current @ max: 21.29 A
P(in) @ max: 236.4 W
P(out) @ max: 159.0 W
Efficiency @ max: 67.3 %
Torque: 0.18 Nm
  0.13 lbf.ft
Climb Capacity: 2196 m
  7205 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 78 km/h
  48 mph
est. Speed (vertical): 29 km/h
  18 mph
est. rate of climb: 9.6 m/s
( ~65...70° ) 1880 ft/min

 

And for a 10x7 APC-E prop

Remarks:  
  • The airflow at the propeller blade will stall. Therefore the static thrust and max. current may not be reached. On ground you will measure *Stall Thrust* as maximum.
  • 27.0km/h / 16.8mph - above this airspeed stall at the propeller blade will have disappeared completely.
Battery
Load: 14.41 C
Voltage: 10.54 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 3.5 min
Mixed Flight Time: 7.8 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 23.06 A
Voltage: 10.54 V
Power: 243.1 W
  Motor @ Maximum
Current: 23.06 A
Voltage: 10.40 V
Revolutions*: 8069 rpm
electric Power: 239.8 W
mech. Power: 167.0 W
Efficiency: 69.6 %
est. Temperature: 70 °C
  158 °F
 
Thermal Curve
3 7 15 23 s
43 54 64 68 °C
109 129 148 154 °F
  Propeller
Static Thrust: 1279 g
  45.1 oz
Revolutions*: 8069 rpm
Stall Thrust: 1062 g
  37.5 oz
avail.Thrust @ 0 km/h: 1062 g
avail.Thrust @ 0 mph: 37.5 oz
Pitch Speed: 86 km/h
  53 mph
Tip Speed: 386 km/h
  240 mph
specific Thrust: 4.43 g/W
  0.16 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 320 W/kg
  145 W/lb
Thrust-Weight: 1.60 : 1
Current @ max: 23.06 A
P(in) @ max: 256.0 W
P(out) @ max: 167.0 W
Efficiency @ max: 65.2 %
Torque: 0.20 Nm
  0.15 lbf.ft
Climb Capacity: 2188 m
  7178 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 84 km/h
  52 mph
est. Speed (vertical): 36 km/h
  22 mph
est. rate of climb: 10.3 m/s
( ~85...90° ) 2028 ft/min

 

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1 hour ago, Fly Boy 3 said:

I would like to fit this motor to my Model Pushycat for this season. I have obtained a Turnigy D2836/8 1100kv.  Wondered what prop size ?  Thanks

What is the distance between the booms? It will dictate the max prop diameter.

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Looking at the plans, you are probably going to want to use a much smaller prop if only to improve hand clearance when launching. This would mean using a higher Kv motor, probably between 1700 Kv and 2000 Kv, or running on a 4 cell battery.

On a 4 cell battery, this is what you get with and 8x5 APC-E with that motor

Remarks:    
Battery
Load: 10.63 C
Voltage: 14.25 V
Rated Voltage: 14.80 V
Energy: 23.68 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 4.8 min
Mixed Flight Time: 9.7 min
Weight: 184 g
  6.5 oz
  Motor @ Optimum Efficiency
Current: 12.79 A
Voltage: 14.31 V
Revolutions*: 13587 rpm
electric Power: 183.0 W
mech. Power: 145.4 W
Efficiency: 79.5 %
      
      
 
Wattmeter readings
Current: 17.02 A
Voltage: 14.25 V
Power: 242.5 W
  Motor @ Maximum
Current: 17.02 A
Voltage: 14.15 V
Revolutions*: 12859 rpm
electric Power: 240.7 W
mech. Power: 189.3 W
Efficiency: 78.7 %
est. Temperature: 57 °C
  135 °F
 
Thermal Curve
3 7 15 23 s
38 46 53 56 °C
100 114 127 132 °F
  Propeller
Static Thrust: 1139 g
  40.2 oz
Revolutions*: 12859 rpm
Stall Thrust: - g
  - oz
avail.Thrust @ 0 km/h: 1139 g
avail.Thrust @ 0 mph: 40.2 oz
Pitch Speed: 98 km/h
  61 mph
Tip Speed: 493 km/h
  306 mph
specific Thrust: 4.73 g/W
  0.17 oz/W
  Total Drive
Drive Weight: 334 g
  11.8 oz
Power-Weight: 315 W/kg
  143 W/lb
Thrust-Weight: 1.42 : 1
Current @ max: 17.02 A
P(in) @ max: 251.8 W
P(out) @ max: 189.3 W
Efficiency @ max: 75.2 %
Torque: 0.14 Nm
  0.1 lbf.ft
Climb Capacity: 2186 m
  7172 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 16.0 g/dm²
  5.2 oz/ft²
Cubic Wing Load: 2.3  
est. Stall Speed: 19 km/h
  12 mph
est. Speed (level): 65 km/h
  40 mph
est. Speed (vertical): 27 km/h
  17 mph
est. rate of climb: 7.6 m/s
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21 minutes ago, Shaun Walsh said:

These are the results for a 3 cell battery with a 9x5 APC-E prop

Battery
Load: 9.39 C
Voltage: 10.73 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 5.4 min
Mixed Flight Time: 9.4 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 15.02 A
Voltage: 10.73 V
Power: 161.2 W
  Motor @ Maximum
Current: 15.02 A
Voltage: 10.64 V
Revolutions*: 9385 rpm
electric Power: 159.9 W
mech. Power: 122.9 W
Efficiency: 76.8 %
est. Temperature: 48 °C
  118 °F
 
Thermal Curve
3 7 15 23 s
35 40 45 47 °C
94 104 113 117 °F
  Propeller
Static Thrust: 901 g
  31.8 oz
Revolutions*: 9385 rpm
Stall Thrust: - g
  - oz
avail.Thrust @ 0 km/h: 901 g
avail.Thrust @ 0 mph: 31.8 oz
Pitch Speed: 72 km/h
  45 mph
Tip Speed: 404 km/h
  251 mph
specific Thrust: 5.63 g/W
  0.2 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 208 W/kg
  94 W/lb
Thrust-Weight: 1.13 : 1
Current @ max: 15.02 A
P(in) @ max: 166.7 W
P(out) @ max: 122.9 W
Efficiency @ max: 73.7 %
Torque: 0.13 Nm
  0.1 lbf.ft
Climb Capacity: 2447 m
  8028 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 72 km/h
  45 mph
est. Speed (vertical): 10 km/h
  6 mph
est. rate of climb: 7.5 m/s
( ~45...50° ) 1478

ft/min

 

 

And the results for a 10x6 APC-E prop 

Battery
Load: 13.31 C
Voltage: 10.58 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 3.8 min
Mixed Flight Time: 7.9 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 21.29 A
Voltage: 10.58 V
Power: 225.2 W
  Motor @ Maximum
Current: 21.29 A
Voltage: 10.45 V
Revolutions*: 8358 rpm
electric Power: 222.6 W
mech. Power: 159.0 W
Efficiency: 71.4 %
est. Temperature: 64 °C
  147 °F
 
Thermal Curve
3 7 15 23 s
41 50 59 63 °C
105 122 138 144 °F
  Propeller
Static Thrust: 1176 g
  41.5 oz
Revolutions*: 8358 rpm
Stall Thrust: - g
  - oz
avail.Thrust @ 0 km/h: 1176 g
avail.Thrust @ 0 mph: 41.5 oz
Pitch Speed: 76 km/h
  47 mph
Tip Speed: 400 km/h
  248 mph
specific Thrust: 5.28 g/W
  0.19 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 295 W/kg
  134 W/lb
Thrust-Weight: 1.47 : 1
Current @ max: 21.29 A
P(in) @ max: 236.4 W
P(out) @ max: 159.0 W
Efficiency @ max: 67.3 %
Torque: 0.18 Nm
  0.13 lbf.ft
Climb Capacity: 2196 m
  7205 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 78 km/h
  48 mph
est. Speed (vertical): 29 km/h
  18 mph
est. rate of climb: 9.6 m/s
( ~65...70° ) 1880 ft/min

 

And for a 10x7 APC-E prop

Remarks:  
  • The airflow at the propeller blade will stall. Therefore the static thrust and max. current may not be reached. On ground you will measure *Stall Thrust* as maximum.
  • 27.0km/h / 16.8mph - above this airspeed stall at the propeller blade will have disappeared completely.
Battery
Load: 14.41 C
Voltage: 10.54 V
Rated Voltage: 11.10 V
Energy: 17.76 Wh
Total Capacity: 1600 mAh
Used Capacity: 1360 mAh
min. Flight Time: 3.5 min
Mixed Flight Time: 7.8 min
Weight: 138 g
  4.9 oz
  Motor @ Optimum Efficiency
Current: 9.87 A
Voltage: 10.80 V
Revolutions*: 10227 rpm
electric Power: 106.7 W
mech. Power: 84.0 W
Efficiency: 78.8 %
      
      
 
Wattmeter readings
Current: 23.06 A
Voltage: 10.54 V
Power: 243.1 W
  Motor @ Maximum
Current: 23.06 A
Voltage: 10.40 V
Revolutions*: 8069 rpm
electric Power: 239.8 W
mech. Power: 167.0 W
Efficiency: 69.6 %
est. Temperature: 70 °C
  158 °F
 
Thermal Curve
3 7 15 23 s
43 54 64 68 °C
109 129 148 154 °F
  Propeller
Static Thrust: 1279 g
  45.1 oz
Revolutions*: 8069 rpm
Stall Thrust: 1062 g
  37.5 oz
avail.Thrust @ 0 km/h: 1062 g
avail.Thrust @ 0 mph: 37.5 oz
Pitch Speed: 86 km/h
  53 mph
Tip Speed: 386 km/h
  240 mph
specific Thrust: 4.43 g/W
  0.16 oz/W
  Total Drive
Drive Weight: 284 g
  10 oz
Power-Weight: 320 W/kg
  145 W/lb
Thrust-Weight: 1.60 : 1
Current @ max: 23.06 A
P(in) @ max: 256.0 W
P(out) @ max: 167.0 W
Efficiency @ max: 65.2 %
Torque: 0.20 Nm
  0.15 lbf.ft
Climb Capacity: 2188 m
  7178 ft
  Airplane
All-up Weight: 800 g
  28.2 oz
Wing Load: 49.2 g/dm²
  16.1 oz/ft²
Cubic Wing Load: 12.2  
est. Stall Speed: 33 km/h
  20 mph
est. Speed (level): 84 km/h
  52 mph
est. Speed (vertical): 36 km/h
  22 mph
est. rate of climb: 10.3 m/s
( ~85...90° ) 2028 ft/min

 

Just checked and the 10x6 and 10x5 current draw are above the motors max 18A rating.

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Managed to eventually find spec of this motor. It suggests 7x3 on 3s. Looks like this motor is not for this model.  Wonder what other Pushycat fliers are using considering I don’t need speed at my age.  Thanks

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9 minutes ago, Fly Boy 3 said:

Managed to eventually find spec of this motor. It suggests 7x3 on 3s. Looks like this motor is not for this model.  Wonder what other Pushycat fliers are using considering I don’t need speed at my age.  Thanks

https://hobbyking.com/en_us/turnigy-d2836-8-1100kv-brushless-outrunner-motor.html

 The 7x3 prop recommendation is for a 4s battery.

4-Max recommendation.

https://www.4-max.co.uk/customermodels56.htm

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IMG_20240307_132917.thumb.jpg.5dfd6a48aa36bd4937feae021923f328.jpgThis is the tail end of my very old pushycat which is still flying. The motor is an outrunner with a high kv, the prop is 7 x 5. I get about 6 mins flight time with 3s 2200 battery.

3 hours ago, Shaun Walsh said:

 

 

3 hours ago, Shaun Walsh said:

 

 

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13 minutes ago, Fly Boy 3 said:

Lovely looking model. C57. No need to weigh model as I have this info now. Can you give more details of your motor such as kv and wattage if possible.  Thank you.

The motor details are all in the link FB3. Just click on the underlined ‘Megamotor 16/15/4’ text in my earlier post 🙂.

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My Pushycat has been clocked at 82mph using a Speedflea GPS maximum speed logger.

 

One thing I would point out, is the torque roll effect that mine suffers on launch. I have to launch with my left hand while applying full left aileron with my right, otherwise the model is prone to rolling hard right and crashing before it can get enough flying speed for the flight controls to have much effect. I have established this as a result of flying it regularly (and crashing on launch several times!) since 2005.

 

This is with a 6x4 prop. KA, do you not find this effect even more pronounced with a 9 inch prop?

Edited by EvilC57
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5 minutes ago, EvilC57 said:

My Pushycat has been clocked at 82mph using a Speedflea GPS maximum speed logger.

 

One thing I would point out, is the torque roll effect that mine suffers on launch. I have to launch with my left hand while applying full left aileron with my right, otherwise the model is prone to rolling hard right and crashing before it can get enough flying speed for the flight controls to have much effect. I have established this as a result of flying it regularly (and crashing on launch several times!) since 2005.

 

This is with a 6x4 prop. KA, do you not find this effect even more pronounced with a 9 inch prop?

Many years ago a clubmate of mine put a Fox 60 in a KK Outlaw. Torque roll was vicious and it could only be hand launched on less than half throttle and even then it flew like a wet dog having a good shake until it built up speed.

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