Hi @axgib , what is the motor type you attached to this smaller prop (as I can see it is about 109mm diameter), I think to try double motor setup with those two props. Please provide your motor details and power you matched to this prop, which are below:
A propeller made of plastic on a 3D printer will have very little efficiency. Plastic blades will bend at max RPM, so they must be thicker than blades of aluminum, steel, carbon, titanium. The ideal blade must be very smooth and solid!
Not really. My SLS nylon printed prop is slightly flexible and has a slightly rough surface. Still does 40kph. It probably would be faster if it was aluminium, but it certainly does not have to be. PC is also tough.
Slightly flexible blades and a rough surface may not affect speed, but will reduce efficiency. Reducing efficiency reduces the length of the trip.
I have a propeller for racing boats on the table that has a speed of about 180 km / h - the blades are smooth as a mirror and hard as steel. It is not possible to print such a propeller from nylon.
Your propeller has an efficiency of about 5%, aluminum should be about 10%. If you need low efficiency propeller, you really do not need either aluminum, carbon, steel or titanium.
Please be constructive, show us your design instead of teaching people that already run e-foils with proven designs. This forum is not about designing the theoretical optimized setup but rather to exchange ideas and experience, so I suggest you either contribute or stop spamming the forum.
My opinion that it is not possible to produce a high-quality plastic propeller on a 3D printer for e-foil using FDM is not a spam, but a very important consideration for every builder (even for you). I recently printed a high-efficiency propeller and is totally unusable for propelling each vessel because the blades already bend at very low RPMs. If I made the blades stronger, the propeller’s efficiency would decrease. The efficiency of each propeller is the most important parameter !!!
@Dynamik I agree that a 3D printed propeller will never be as efficient as a CNC prop, Cast aluminium or even plastic injected moulded plastic .
Some of us use 3D printer props as we develop just hobby efoils for fun.
Can you post details of a more efficient efoil prop option that the group can discuss ? or purchase. Some time ago we were promised another super efficient design by another propeller expert user name was “WNT” but I do not recall seeing any updates.
You may want to contact “WNT” and work together if you & WNT could work together we may see some excellent new options on the market. I will buy one & review it.
Yeah it is SPAM @WNT, @Dynamik or whatever other name you want to go by! All people here know that 3D printed propellers are not high quality or optimised! You just continually stating the obvious!
However, 3D printed props are CHEAP, easy to make design tweaks to and reliable enough to get all of us that actually do foil for fun. My prop cost me about £2 to print. It’s still working and having fun.
Why don’t you design some open-source props for this community and then people can print, mould or CNC them and test them out. At least that way you’ll add something constructive!!!
I was easily able to get an H105 profile on my 8cm chord 3D printed propeller without increasing the thickness. If I went any thinner i would be losing L/D.
Maybe it flexes under load, but why is this bad? Don’t you want to get as close to an elliptical loading profile as possible? i.e.decreased tip loading. (look up oswald efficiency in your aero text book).
Or just look at the wing of a 787 while it is flying.
Surface roughness: would like to see some data for this claim as well. How do you know you aren’t renergizing the turbulent boundary layer and preventing separation or a laminar separation bubble?
Are we not operating at a totally different reynolds number than your race boat? Why does it matter if the propellers dont look identical.
I just wanted to ask for a bit of help with JavaProp if anyone here can help.
there are now new value fields for Shroud Chord and Shroud Angle. I can guess what these refer to, but what are the units here? Can anyone confirm values for that?
Regarding how to apply the generated models to the spinner: I know it has been discussed how do close these geometries. As far as how to join them to the spinner, what is the intended method there? It seems that the width of the blade is what follows the chosen diameter. But then what is the best way to join the rest of the surface to the rotor other than the midpoint? I assume it’s not intended to be “warped to fit” so as not to change the profile. Or is it? Do we continue a rough estimation towards the spinner and not worry about being accurate? Sorry for all the what-ifs.
Thanks to anyone for their input on either factor.
Just thought I’d update here with the JavaProp shroud settings after speaking with Martin. Most importantly, it’s important to remember that the “shrouded rotor” option is still experimental and probably not very accurate because one would need a 3D shape and more details for an accurate model. So it can only give a “feeling” for the main effects. Among other factors.
But here’s what he wrote about the settings since they’re not in the manual:
The shroud is input as a dimensionless chord length ratio c_shroud_profile / propeller_radius. The angle is given in degrees and defines the inclination of the shroud profile like on a wing section. A positive angle opens the shroud at the front and closes it towards the rear, as one would use for a propulsor. A negative angle is useful for modeling a shrouded wind-turbine where the shroud opens towards the rear. The shroud profile is assumed to be aerodynamically symmetric usually one would use a negatively cambered airfoil (like an inverted Clark-Y like section) which can be taken into account by adjusting the shroud angle according to the zero lift angle of the asymmetrical section.
I’m not quite fully getting the chord length value, but I’ll play around with it to see if I can give myself a mental picture of what’s going on.
Anyhow…hope this helps and maybe someone else has played around with this here.
Hello FR, can you sell your folding prop to the european members of this forum? instead of going to Lift: prop goes from your factory to USA back to europe… not really the best solution to reduce CO2 emission. And I don’t even talk about taxes and transport cost. thanks a lot for your answer
I would like to take this opportunity to ask you for your opinion on carbon lamination of a 3D printed helix in PETG OR ASA-X? Is this good or does it make the helix too rigid? Have you already done any tests?
Does he want to laminate better in carbon or fiberglass?
Hi there I’m about to do a prop design with onshape, wondering if you could share yours? I’ve done a bunch of basic stuff in it, but never surface modeling, so a bit stumped in terms of how to best make each prop have an aerofoil shape in profile. Thanks!
I will buy one & review it.