Seeker Knowledge
The best thing that came from all of our testing is a 3D Printer version odone by Ole Hermann Godø. Download the files: 3D Printed Prop and Kort Nozzle Ole_Herman_God0_Thruster.7z
Drawing: 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) 3D_Print_Prop_V1.pdf
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. www.bluerobotics.com
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
| Forward | Reverse | |||||||||||||
| Manuf | Part Number | Blades | Diam mm | Pitch mm | Volts | Amps | Watts | Thrust grams | Grams /Watts | Source | ||||
| Rule? | Impeller | 3 | n/a | 12 | 2.80 | 33.60 | 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 | OpenROV | ||||
| Graupner | 2308.65 | 3 | 65 | 34 | 11 | 6.00 | 66.00 | 1100 | 16.67 | OpenROV | ||||
| Custom | 65mm x 24mm | 3 | 65 | 24 | 12 | 10 | 120 | 454 | 3.78 | 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 | 1111 | 8.57 | SVSeeker | ||
| Eflight | Delta V-15 w/Stock Duct | 5 | 69 | ? | 12 | 10 | 120 | 1360 | 11.33 | 737 | 6.14 | SVSeeker | ||
| Graupner | 2308/65 | 3 | 65 | 34 | 12 | 9.5 | 114 | 1616 | 14.18 | 9.75 | 117 | 694 | 5.93 | SVSeeker |
HomeBuiltROV’s Testing: homebuiltrovs.com/mayfair750test.html ↗
OpenROV Testing: Test Stand Test Results openrov.com/forum/topics/thruster-testing-stand ↗ openrov.com/profiles/blogs/preliminary-propeller-efficiency-tes… ↗ Rotor, 5-Blade: Delta-V 15 Part # EFLDF151 $7.99 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. OpenROV Parts 2213N 800Kv Brushless Motor 3mm shaft, Outrunner Max 9.5A 11V OpenROV Parts EZRUN 18A Brushless ESC $24 Output: Continuous 18A, 2-3S LiPo
OpenROV Parts
2213N 800Kv Brushless Motor 3mm shaft, Outrunner Max 9.5A 11V hobbyking.com/hobbyking/store/__8622__2213N_800Kv_Brushless_Mot… ↗
EZRUN 18A Brushless ESC Output: Continuous 18A, 2-3S LiPo 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. 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. 68 mm diameter, 24 mm pitch, ROV propeller
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. youtube.com/watch?… ↗
Other Motor Options Gear head motors: Gimbal Drive Motors: Servo Motors: Ceramic bearings: pololu.com/category/51/pololu-metal-gearmotors ↗ hobbyking.com.au/hobbyking/store/__976__973__FPV_Telemetry-Gimb… ↗ servocity.com/html/planetary_gearbox.html ↗ bocabearings.com ↗
Prop Chart: Prop Calculator: Servo Gears: funrcboats.com/prop_chart1.htm ↗ radiocontrolinfo.com/RCcalculator/BoatCalculator.php ↗ servocity.com ↗
