Pump Jet (32mm 2212 Motor)

thingiverse

An offshoot of my project https://www.thingiverse.com/thing:4606971 RC Pump Jet boat, I modeled a stand alone water jet originally intending boat to be modular in design. After consideration I decided to just integrate the pump jet with the boat body rather than try to seal the modular parts against water ingress. This model might still be useful for someone though. I've also kept the motor separate from the pump jet in case you want to model your own motor housing for different motors. Note this design has inlet and outlets for water cooling, you will need to plug or remove these if not needed otherwise it will air lock. To prime the pump I found that initially starting at low speed or modulating the speed up and down was needed, with the 3/19/2021 updates to stator and nozzle it reliably runs at all thrust levels once primed - sealing of the inner running surfaces of the pump inlet via wax, epoxy or flexible paint is needed for reliable operation. Also note that for the part Inlet Duct you will need to specify supports everywhere as there is an unavoidable overhang for the mounting plate otherwise print settings will be the same as specified for the boat project mentioned above. Depending on your weight limitations you might want to specify more walls than my boat project to make the parts sturdier - I was constrained by the displacement of my hull. BOM: - Motor: 2212 if using the provided mount https://www.aliexpress.com/item/32672300112.html or https://www.aliexpress.com/item/1904754775.html (also something of interest is the 2217 motor - I think it has a 4mm vs 3.175 mm shaft but I imagine the baseplate is the same - you'd need to adjust the mount position and source a 4mm to 3mm cardan joint but it might work better than the relatively small 2212) - Prop: 32mm with 100 mm shaft (note get the 10 cm one with 3.18 motor as the 2212 shaft is 3.175 mm - I initially tried to model an axial flow impeller but I found this purchased item to be far more sturdy (*update as of 3/21/2021 there is an experimental two stage impeller uploaded). Advantages are it has built in high speed bearings and replacement props can be purchased from here as well. I also added provisions for a diy 3mm shaft using 623 bearings) https://www.aliexpress.com/item/32714017489.html https://www.aliexpress.com/item/32528668718.html - Servo: sized for 9g servo (important you will want to waterproof or find an alternate waterproof servo) if anyone knows a reliable and waterproof 9g model please post in comments - M3 X 6 X 5.3 Embedded Nuts (old link no longer works - possible substitution M3 X D5 X L6) https://www.aliexpress.com/item/4000232858343.html - M3 Machine Screws (Button head and Flat head) https://www.aliexpress.com/item/32798146322.html or stainless https://www.aliexpress.com/item/32934186482.html Thrust vector nozzle, stator and motor cooling impeller should be printed in TPU for layer adhesion qualities. For post processing pics please go to https://www.thingiverse.com/thing:4606971 Note that the embedded nuts go on the inner side for this model while they go on the outer face for the boat project due to access issues. The boat model also has an alternate motor mount with base which might suit some builders better as well as a template for custom motors other than the 2212. Josh at Flite Test did a good vid about waterproofing RC electronics with Peter Sripol (Flite Test | Waterproofing Electronics) Enjoy >^.^< also let me know if there are any issues as my main focus for the near term will be the RC boat project and changes / improvements there may not make it here. Updated 10/3/2020, removed the bar surrounding the servo to improve printability. Updated 10/7/2020, improved printability by modifying the fillet around the shaft support Update 10/9/2020, After a print failure of the protective grid on the intake as well as impact durability test failures I have replaced with a filament heat stake method as shown in my boat project post processing pics. Insert 1.75 mm filaments into the slots and use a low temp soldering iron to melt the ends into the inlet - you could also use servo wire and glue in place...unless you like grinding baby fish into a pulp...u monster Updated 10/11/2020, increased clearance for the prop shaft Updated 10/15/2020, motor mount was a tight fit, increased clearances - note if print elephant foots you will still need to trim mount a bit Updated 10/18/2020, Added a variable trim ride plate. A bent 1.5 mm servo wire serves as the retention and adjustment mechanism, backup retention provided by an embedded nut and M3 X 10 screw + spring. Joint held by filament joint. Note stator profile carried over from my boat project and outer gasket allowance missing :P caturday cat prefers to nap >^.^< it is a feature not a deficiency Updated 10/20/2020, some weird artifacts were cropping up in cooling impeller during slicing, increased to high resolution stl and fixed wall width Updated 10/21/2020 increased prop clearance on stator bowl Updated 10/25/2020 improvements to trust vector nozzle to allow M3 X 5 X 6 mm embedded nuts to ride on the inner race of the 623zz bearing Update 11/6/2020, feedback on my boat project suggest that a thrust vector nozzle with a slight pitch up would be beneficial - added a thrust vector nozzle with a 5 degree pitch up. If you find that your own boat is going nose down this new nozzle will help :). Added a 10 deg pitch nozzle if your CG/CB requires it Update 11/18/2020, first functional test of the waterjet - I found that even with TPU gasket air and water would spray out thus sealing the stator bowl to inlet duct body with silicone or glue is necessary. I found an issue with air locking - I don't fully understand the cause but experimentally determined a way to resolve this via a pending modification to the thrust vector nozzle. Update uploaded (Thrust Vector Nozzle Variable Pitch) but untested - I'll hopefully get a chance to print and test by tmw. Testing confirms the air lock issue is resolved with this new nozzle - there is some loss of efficiency. I don't really know why this fixes the air lock but I suspect the stator bowl fins were not redirecting enough of the rotational energy generated by the prop resulting in an area of low pressure which would draw air in from behind the outlet...without high speed cameras or CFD I can't really say. N7 Cat says "wut he trying 2 say iz I putz mah paw ober da nozzle and dat fixes it" 11/21/2020 did some more study on propulsor units and updated the pitch and number of stator vanes - 5 vane stator uploaded - will test later and delete original if testing displays improvement. Test showed marked improvement in both trust and elimination of air lock using the 5 vane stator - original deleted. For anyone else designing or trouble shooting other pump jets on thingiverse the number of stator vanes needs to be a prime number and different than the number of prop blades otherwise a standing wave can develop. At some point in the future I might experiment with a properly designed axial flow prop and stator - salt sintering might be able to create a strong enough part for use as a prop. 11/25/2020 reverted thrust vector nozzle to neutral pitch 2/16/2021 added a printable gasket 3/17/2021 modified the thrust vector nozzle to try and fix an intermittent airlock issue 3/19/2021 tweaked the thrust vector nozzle and modified the stator bowl by extending parallel fin surfaces in attempt to reduce rotational energy of water 3/21/2021 experimental two stage impeller / stator uploaded - my first try at a printed impeller - going to test TPU and PETG but am skeptical about the robustness of either. Note there are two versions of the second stage impeller 3/23/2021 fixed some clearance and mounting issues with the experimental impellers 3/25/2021 fixed some clearance issues with the mid stator causing it to bind to the second stage shaft 3/25/2021 had a chance to test the two stage impeller system and found flow was disrupted past 40% throttle - I suspect the pitch angle is too aggressive - removed files until I can remodel all the components 3/26/2021 updated inlet duct in preparation for two stage impeller system, old model was missing a cutout for the impeller 3/30/2021 tested stage 1 impeller and thrust feels like it has doubled :D moar powah! You will need to print new model inlet duct before using. Will test the two stage setup soon. For now stage 1 works with existing stator and improves thrust 3/31/2021 tested two stage setup and it was overall a success, flow rate is higher with just the single stage but priming is much faster with the two stage setup. In fact device will prime even under full thrust, making for more reliable operation in choppy water. Two stage only functions with the new stator bowl axial, if you are only using the new stage one impeller it will still work with the old stator. Flow rates were getting so high that the nozzle started to impede flow, an open nozzle is now uploaded 6/25/2021 stronger servo mount on part inlet duct 6/30/2021 improved motor cooling impeller, larger fins, improved filleting, removed thin shroud, now secured by butting against cardan joint 7/11/2021 uploaded step files of the inlet duct and 2212 motor mount - note I combined the two parts into a single step file for alignment and spacing when modeling - when designing you will probably want to re-separate as print orientation for the mount should be rotated 90 degrees 8/1/2021 it was getting tedious to maintain two different sets of designs so motor mount is now just the same model as the boat project - wires can be routed through lower duct 8/2/2021 uploaded variants without water cooling, for the no water cooling versions of the stator bowl and mid stator please use the stl files from the boat project 8/5/2021 improved motor cooling impeller profile 8/11/2021 stage two impeller was shearing from the embedded nut - altered stage two impeller so that embedded nut enters from other end and added some more material to the embedded nut hole to hopefully prevent this 8/12/2021 moved motor mount 10mm closer to inlet duct in order to improve strength of the stage 2 impeller 8/15/2021 unifying parts between boat project and pump jet. Updated water cooling stator bowl, uses embedded nut for more secure water nipple retention. Note water cooling is now intended to passively exit vs being pulled by pump jet (if this is insufficient let me know and I might revisit)