Thrusters

3D Printed Prop and Kort Nozzle |
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The best thing that came from all of our testing is a 3D Printer
version odone by Ole Hermann Godø. Download the files:
Ole_Herman_God0_Thruster.7z
Drawing:
3D_Print_Prop_V1.pdf
Performance numbers in forward are:
12v
1A = 0,5kg - 1,1lb - 17,6oz
5A = 1,5kg - 3,3lb - 53oz
10A = 2,3kg - 5lb - 81oz
13A = 2,65kg - 5,8lb - 93,5oz
19A = 3,3kg - 7,3lb - 116oz (Max)
Reverse:
1A = 0,45kg - 1lb - 16oz
5A = 1,3kg - 2,8lb - 45,8oz
19A = 2,9kg - 6,4lb - 102oz (Max)
ROV THRUSTER
3D printed thruster for hobby ROV. 3D printed parts. NTM Prop Drive
2836 750KV brushless motor.
The design Ole Hermann Godø created was inspired by the Blue
Robotics Kickstarter which now has there products for sale at
www.bluerobotics.com.
Starting at $100, they are relatively expensive thrusters as
compared to Ole Hermann Godø's creation, but they are very good
quality. The only possible flaw is the windings on the out
runner motor have not been potted which leaves the windings exposed
to abrasion from the sea-water.
Thruster Prop Testing
Our starting point for testing will be to duplicated the OpenROV
groups test done on the Rotor, 5-Blade: Delta-V 15
Part # EFLDF151 blade as a baseline. Then test additional
blade to try and imporve on the amp-hour/thrust ratio achieved by
OpenROV and HomeBuiltROV's
Motors Used in Test Below:
HomeBuiltROVs: 750 gph bilge pump
OpenROV: 2213N 800Kv Brushless Motor
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Forward |
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Reverse |
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Manuf |
Part Number |
Blades |
Diam
mm |
Pitch
mm |
Volts |
Amps |
Watts |
Thrust grams |
Grams
/Watts |
Amps |
Watts |
Thrust grams |
Grams
/Watts |
Source |
Rule? |
Impeller |
3 |
n/a |
n/a |
12 |
2.80 |
33.60 |
n/a |
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n/a |
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HB ROV |
Robbe |
ROB1471-72 |
3 |
50 |
42 |
12 |
6.00 |
72.00 |
817 |
11.35 |
5.50 |
66.00 |
635 |
9.62 |
HB ROV |
Robbe |
ROB1464-65 |
3 |
60 |
45 |
12 |
6.50 |
78.00 |
680 |
8.72 |
6.30 |
75.60 |
363 |
4.80 |
HB ROV |
Robbe |
ROB1487 |
3 |
60 Kort |
45 |
12 |
6.40 |
76.80 |
680 |
8.85 |
6.00 |
72.00 |
363 |
5.04 |
HB ROV |
X-Brand |
RA3007 |
2 |
35 |
? |
12 |
4.20 |
50.40 |
590 |
11.71 |
4.00 |
48.00 |
408 |
8.50 |
HB ROV |
X-Brand |
RA3008 |
2 |
40 |
? |
12 |
5.20 |
62.40 |
726 |
11.63 |
5.00 |
60.00 |
499 |
8.32 |
HB ROV |
X-Brand |
RA3009 |
2 |
45 |
? |
12 |
5.80 |
69.60 |
726 |
10.43 |
5.00 |
60.00 |
590 |
9.83 |
HB ROV |
X-Brand |
RA3010 |
2 |
50 |
? |
12 |
6.10 |
73.20 |
771 |
10.53 |
6.00 |
72.00 |
635 |
8.82 |
HB ROV |
Graupner |
GR1 124 |
2 |
35 |
? |
12 |
2.15 |
25.80 |
408 |
15.81 |
2.00 |
24.00 |
272 |
11.33 |
HB ROV |
Graupner |
GR1 128 |
2 |
45 |
? |
12 |
6.00 |
72.00 |
680 |
9.44 |
5.80 |
69.60 |
454 |
6.52 |
HB ROV |
Graupner |
GR230840 |
3 |
40 |
? |
12 |
2.65 |
31.80 |
590 |
18.55 |
1.95 |
23.40 |
136 |
5.81 |
HB ROV |
Graupner |
GR230850 |
3 |
50 |
? |
12 |
4.45 |
53.40 |
998 |
18.69 |
3.65 |
43.80 |
272 |
6.21 |
HB ROV |
Graupner |
GR230850 |
4 |
50 |
? |
12 |
3.80 |
45.60 |
680 |
14.91 |
3.10 |
37.20 |
363 |
9.76 |
HB ROV |
Eflight |
Delta V-15 |
5 |
69 |
? |
11 |
6.00 |
66.00 |
480 |
7.27 |
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OpenROV |
Graupner |
2308.65 |
3 |
65 |
34 |
11 |
6.00 |
66.00 |
1100 |
16.67 |
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OpenROV |
Custom |
65mm x 24mm |
3 |
65 |
24 |
12 |
10 |
120 |
454 |
3.78 |
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SVSeeker |
Eflight |
Delta V-15 |
5 |
69 |
? |
12 |
9.91 |
119 |
964 |
8.10 |
10.58 |
127 |
794 |
6.25 |
SVSeeker |
Eflight |
Delta V-15
63mm w/Shroud |
5 |
63 |
? |
12 |
10.8 |
129.6 |
1446 |
11.16 |
10.8 |
129.6 |
1111 |
8.57 |
SVSeeker |
Eflight |
Delta V-15
w/Stock Duct |
5 |
69 |
? |
12 |
10 |
120 |
1360 |
11.33 |
10 |
120 |
737 |
6.14 |
SVSeeker |
Graupner |
2308/65 |
3 |
65 |
34 |
12 |
9.5 |
114 |
1616 |
14.18 |
9.75 |
117 |
694 |
5.93 |
SVSeeker |
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HomeBuiltROV's Testing:
http://www.homebuiltrovs.com/mayfair750test.html
OpenROV Testing:
Test Stand
http://openrov.com/forum/topics/thruster-testing-stand
Test Results
http://openrov.com/profiles/blogs/preliminary-propeller-efficiency-testing

Rotor, 5-Blade: Delta-V 15
Part # EFLDF151 $7.99 |
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Graupner 2308.65 is 200% more
efficient than the 5-Blade: Delta-V 15 at
66w and when the V15 is not in a
shourd. |
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OpenROV Parts
2213N 800Kv Brushless Motor
3mm shaft, Outrunner Max 9.5A 11V |
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OpenROV Parts
EZRUN 18A Brushless ESC $24
Output: Continuous 18A, 2-3S LiPo |
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OpenROV Parts
2213N 800Kv Brushless Motor 3mm shaft, Outrunner Max 9.5A
11V
http://www.hobbyking.com/hobbyking/store/__8622__2213N_800Kv_Brushless_Motor.html
EZRUN 18A Brushless ESC Output: Continuous 18A, 2-3S LiPo
http://www.hobbypartz.com/ezrun-18a-v2-esc-for-rc-car.html
Propeller Selection
We made an attempt to CNC mill our own propellers from Delrin
plastic. The approach was simple, take what we know about 27"
diameter 400 rpm boat propellers and apply it to 2.5" diameter, 6000
rpm propellers.

68 mm diameter, 24 mm pitch, ROV propeller |
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In actually testing this blade preformed very poorly, only
generating 16 oz, 454 grams of thrust with 120 watts. The motor was generating 4,500 to 5,500 rpm as expected so we
believe the a good deal of the problem lies in the thickness of the
blades, which are 2.25mm thick compared to .7mm of the very
efficient Graupner 2308/65 prop or the .9mm blade of the Delta-V 15 fan blade.
Graupner 2308.65 Prop Suppliers:
www.wheelspinmodels.co.uk
www.cornwallmodelboats.co.uk
After taking our various motors apart we found that all but the
HobbyKing Donkey use little bearing on both ends of the coils.
The HobbyKing Donkey has a single brass bearing. We like that
design because it provides no air pocket that will compress and
allow seawater to pass through the bearing. So oil in the
bearing will stay in place longer and collect less debris.

Thermal epoxy for potting the coils. |
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https://www.youtube.com/watch?v=RIOuPMg99GA
Other Motor Options
Gear head motors:
http://www.pololu.com/category/51/pololu-metal-gearmotors
Gimbal Drive Motors:
http://hobbyking.com.au/hobbyking/store/__976__973__FPV_Telemetry-Gimbal_Motors.html
Servo Motors:
http://www.servocity.com/html/planetary_gearbox.html
Ceramic bearings:
http://www.bocabearings.com
Prop Chart:
http://www.funrcboats.com/prop_chart1.htm
Prop Calculator:
http://www.radiocontrolinfo.com/RCcalculator/BoatCalculator.php
Servo Gears: www.servocity.com
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