So I've been thinking about trying to build a jet, but instead of an EDF have a regular motor & 2 blade prop in the duct where the fan would go. I was trying to look for other people who have done this but I can't find anything. Has anyone tried this or know someone who has tried this?
Electric ducted prop?
- Thread starter Oske
- Start date
Jetcrafter_2000
Member
Well if you want the same power like the edf you have to take a much bigger prop (at a lower RPM).
An EDF can just run on these little diameter ducts cause they run on a huge RPM.
A good alternative is to mount the prop on the back of the plane or to mount the prop in a slot in the middle of the plane like in the alpha, bravo and charly jets.
An EDF can just run on these little diameter ducts cause they run on a huge RPM.
A good alternative is to mount the prop on the back of the plane or to mount the prop in a slot in the middle of the plane like in the alpha, bravo and charly jets.
Pieliker96
Elite member
It certainly can work, see a fantastic example here.
I've always wanted to try this out with those little emax motors they use on the gremlins.
The thing about using a ducted prop is that the prop is normally a lot larger radially than an equivalent EDF and produces much less thrust:
a 3" 3-bladed prop on an 1106 will produce 250g on 3s, whereas an equivalent sized fan (~70mm) produces upwards of 800g of thrust at the same voltage.
To get the same thrust out of an equivalently sized prop, you'd have to spin it really, really fast, which sort of negates the purpose.
That being said, the prop would be vastly more efficient: The 3" prop above draws around 90 watts whereas the EDF draws about 500.
Another advantage of the prop is that the power system weighs much less, but that means that the structure of the plane itself now constitutes a much more significant portion of the weight. If you're planning on using a ducted prop, you'll have to build really, really light, simply due to a massive reduction in thrust over an equivalent-sized EDF.
I've always wanted to try this out with those little emax motors they use on the gremlins.
The thing about using a ducted prop is that the prop is normally a lot larger radially than an equivalent EDF and produces much less thrust:
a 3" 3-bladed prop on an 1106 will produce 250g on 3s, whereas an equivalent sized fan (~70mm) produces upwards of 800g of thrust at the same voltage.
To get the same thrust out of an equivalently sized prop, you'd have to spin it really, really fast, which sort of negates the purpose.
That being said, the prop would be vastly more efficient: The 3" prop above draws around 90 watts whereas the EDF draws about 500.
Another advantage of the prop is that the power system weighs much less, but that means that the structure of the plane itself now constitutes a much more significant portion of the weight. If you're planning on using a ducted prop, you'll have to build really, really light, simply due to a massive reduction in thrust over an equivalent-sized EDF.
I get what you mean, but I'm not talking about a prop in slot or a pusher. I'm talking about using something like a c pack motor and a 10" prop inside of a duct that I base a jet around. The idea isn't to create a jet, but to make a somewhat large scale but light weight "jet" that used a 10" ducted prop inlayed in the jet rather than a pusher prop on the back. So I guess it's kind of like a prop in slot, but the plane is big enough that the "slot" is just a duct going through the plane.
That post you shared is exactly what I wanted to see. Thank you for sharing it.
About the rest of the things you mentioned, I understand that the thrust won't be as great as a fan, but the idea is to make a sorta slow docile park flyer with the prop inside the plane rather than say a smaller key with a fan or a pusher prop.
Jetcrafter_2000
Member
Ah, that´s what you´re talking about!
I thought you wanted to build a small 50mm EDF with a prop and expect the same thrust out of it
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I thought you wanted to build a small 50mm EDF with a prop and expect the same thrust out of it
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