I’ve had my eyes on these bow prop propellers for a while now. I had an accident with my three blade and decided to give it a try.
There are multiple brands and props out there they are all made to be used in a duct. I managed to find one that’s 140mm in dia.
The prop uses a shear pin to keep it in place and normally a bolt/nut to keep it from falling of the shaft.
The one I choose came with a 11,5-ish mm bore so I decided to adapt it to my 10mm shaft.
First I drilled the bore in the prop to 12mm and the got a 12mm stainless pipe with 1mm walls. I cut the pipe to the right length and used an hydraulic press to fix the pipe in the prop.
I then drilled a hole in the shaft for the shear pin and also made a cut for the clip that hold the prop in place.
Hopefully I will get it in the water for a trial soon.
The hub on the prop is a bit bigger than the hiorth original and I might do a 3D print add on to the torpedo to get a smooth overlap between torpedo and prop.
Nice catch ! Looks to have an efficiency between the Aliexpress 10USD 7 1/4" prop and the Flying Rodeo one.
Do you have an idea of the optimum RPM ?
P175 if in mm does it mean 6.9" pitch ?
Looking forward to you first water trial.
Hi Riwi
May be this propeller would do better in a slightly narrower duct. As far as I can see in your pics there is a gap between the blade tips and the inner surface of your duct. As you will know, at the acting propeller every blade has a pressure side and a suction side. These pressure differences try to short cut over the wide blade tips. Therefore it isnormally a design goal to keep the gap between blade tips and duct as narrow as possible. I don’t know, if the present gap is needed because of any deformation of prop or duct to aviod kontact. Otherwise it could be worth a try to print a new duct.
Look who’s here, the BTQ 140 blade! I know something about that prop, it’s been my daily nightmare for some time on boat thrusters, untill I realized that was “softening” hence bending after some time in water (it’s injection molded out of nylon, hygroscopic, with fiberglass) and we moved up to 50% fiberglass, check if it has a small circle with 50 written inside.
P175 I don’t think refers to pitch, but later I’ll ask to the guy who designed it.
This one push less than 35kgf at 4500rpm I remember…12V motor loaded at almost 3kw max peak. For speed I don’t think its really efficient but for sure it’s very well built.
There’s also a 125mm model, better design, 5blades…traction is made differently (splined shaft). It pushes shy 30kgf at 5k rpm, don’t remember current/power though.
In UK there’s Quick UK in South Hampton, good guys, National importer.
I love the fact that you worked with it, it’s high quality and not a bad prop for the price. The shear pin approach is nice to. Much easier to change the prop if needed.
I can confirm the pitch: 175mm.
Eventually, check the FVSGEL125000A00 - OSP KIT 125 PROPELLER, it has a more aggressive pitch, other than more “directional” as blade profile. Don’t remember the exact pitch but I’ll ask to my former colleagues.
