I just had an idea to convert my Fresh Breeze Monster and FlyPod trike to single-prop electric. I use SolidWorks full-time at the metal fabrication shop where I work, so designing and building a custom bracket/mount to bridge the gap between the engine mounts and the electric motor, batteries and electronics shouldn’t be a problem. I am having trouble scouring this site to find a list of the components I would need to purchase. Am I missing an obvious place to find the specs on each of the following items, and am I missing any components I would need?
Motor (I think I read somewhere that the motor for the sp140 is custom-made for openPPG. Is there any way to buy just that motor?)
Motor controller
Prop (e-prop. Am I safe to assume I should NOT use the 4-bladed scimitar props that come with the Monster?)
Batteries (4 bonka-22000mah-6s-lipo-battery, right?)
Charger I’m thinking HTRC-HT700-DUO-AC-DC-1-8s-Lion-LiPo-Battery-Charger-350W-2-20A-2-Dual
3D-printed throttle (I actually already have the 3D-printed part of this)
Throttle screen
Throttle electronics
Throttle cable
Battery management system
All the firmware I can get off of github.
Do you have any dangers I should look out for in attempting this DIY project?
you would need to contact openPPG to purchase the parts (motor, battery, ESC)
Not worth building the motor. Motor Controller (ESC): contact OpenPPG
I don’t think I’ve seen anywhere where they’ve tested a 4 blade. only 2 and 3 blade options Batteries: you are thinking of the X4 batteries. best option is to buy from OpenPPG directly as it will have a built in BMS Charger: wrong charger, that’s for the X4. Throttle/screen/cable: no files are released yet for the SP140, you might have to wait a while until they get caught up with the initial batch shipped. did you print the x4 throttle? Battery Management System: would come with the battery pack: SP140 Battery | OpenPPG firmware: not released for the SP140 yet as far as I know. I did not check github.
This was super-helpful, thank you! I printed the X4 throttle. I’ll try to get everything from OpenPPG, then. I don’t know if they will sell a partial kit, though
Prop (e-prop. Am I safe to assume I should NOT use the 4-bladed scimitar props that come with the Monster?)
My opinion, possibly worth what you’ve paid for it…The single e-prop would likely be more efficient but if you don’t want to buy a new prop the fresh breeze props should work as long as they match up with the hub. The general consideration for propellers is that the tip speed not exceed around 85% the speed of sound and the pitch is matched to your speed range. Since both props are intended for paramotor flight speeds and are probably around the same diameter you should be looking at a generally compatible setup.
Having said that…considering that the OpenPPG folks are likely doing testing and choosing a propeller that’s optimally loaded against the motor - you’ll probably have a better time with the prop they choose. If you do get that one and have both available it would be interesting to see the results back-to-back.
Lots of good replies here but to add to the prop info: @Pdwhite has been doing extensive testing with lots of different props for the SP140 and we have landed on a couple options that are particularly well optimized. Obviously you could use almost anything that fits but you may be lucky to get half of the flight time and could overheat the motor or ESC etc.
We are trying to make electric accessible for everyone but we also want to ensure a good experience so for now we are focused on our complete system that has been extensively tested together.
A couple of options might be the ticket. A heavier pilot with a smaller wing operating in higher wind might want more pitch speed. A lighter pilot with the lighter battery on a bigger wing in calm conditions would get more run time from a thinner prop.
The motor can be purchased straight from MAD motors(it wont be in full production for a little while so you will need to wait). I went through Alibaba when I bought my m40. I asked them and they said that the M50(the motor on the SP140) will be around $1100. The motor controller for the SP140 is custom but you could probably use the one that MAD motors is selling.
This motor was designed to have tons of torque! It will swing a prop at roughly 2500rpm at full throttle where the 185 swings its props at roughly 3000rpm at full throttle. because of this you need a bigger or more aggressive prop to get the same thrust so a 4 blade prop designed for the moster 185 might actually underprop it.
Like tatawaki said you need a much higher voltage battery(24s) and preferably Li-ion for the safety and energy density. You could probably buy one from Open PPG or if you know how to do it safely you could make your own.
I don’t believe “Monster” was a typo - the Fresh Breeze Monster is a Hirth F33 derived motor (28 HP/21kW) running the double-stacked props. The FB Monster props are 4 blade 122cm (48").
I just looked at the SP140 listing in the OpenPPG store and they have a dual blade and tri-blade option - they are both 140cm (55"). Two or three inches difference…meh…but 7 inches (18cm). Kind of talking about real numbers there. So yeah - the FB prop doesn’t match up to that so well.
Oops, forgot about that. I was thinking of the vittorazi moster 185 which is used by almost everything these days. Almost everyone misspells it and often if you don’t misspell it your computer will try and “correct” the it. Anyway. I still believe that your monster prop would be too small.
