Hello Zach! Thank you for the reply.
The drawing I have at the moment is this one. While I was designing it, one of my main concerns was the riser lines. Take a look at the drawing and you can imagine how they are going to come up.
As soon as I have more details, I’ll post them.
Assembly.pdf (136.0 KB)
Hello Zach! Thank you for the reply.
Interesting idea, perhaps I could implement that in the 0.2 version.
It’s awesome if people come up with new ideas.
but in my humble opinion the existing paramotor designs are already working very well.
The main design flaw is that you can’t forward launch anymore.
I hate forward launch, but just yesterday I was trying three times to pull up my wing in reverse (facing the glider). It just did not work, wind was too slow.
I then turned around and did a successful forward launch (did I say I hate forward launches?)
But the main concern is that this is not about design, it’s about calculations. you may have way too much thrust with your setup. and too much thrust is a waste of energy (and weight).
did you calculate the thrust or airflow ? (not that I could do it…)
Yep, kinda of agree, but without exploration of the new ideas we dont know what could be better. Maybe OpenPPG has hit on the “overall” best design/layout. Some minor improvements to be made yes, like bats , but overall might stay the same. But how do we know until 20 or 100 people try to better it but are not successful. Maybe it will take the 1000th try by someone to come up with the next best design - pls keep trying is my vote and thank you!
With out effort, a path can not change.
With the motor I almost always launch in totally dead wind. I finally mastered using the thrust to pop the wing up. I start with my lines slack, then I run until the lines are tight and the wing starts to come up, then I give it full throttle to pop the wing up. Note: the thrust doesn’t push me forward because it hits the wing so the wing practically comes up with very little forward motion. Just make sure your wing is part way up when you hit the throttle so the thrust doesn’t push you onto your face. You can feel the wing holding you from running… that’s when you know you can give it full throttle.
Yes - - I noticed this technique among the seasoned pilots.
This is a really interesting concept. Advantages over the current design are:
Less noise? Props are bigger and outside the wake of the body, so cleaner air? But the 2nd blade is in dirty air?
The housings might act as duct and improve efficiency due to loss of vorticies?
- Would the lines come up ok around a wide frame in a forward launch?
- Unless the ducts are carbon fiber (which would be cool), I worry about weight?
- I really only know how to forward launch… My one and only reverse launch ended like this: https://www.youtube.com/watch?v=LZb0DuWCsGk, so forward launches would be important for losers like me…
The wing comes up straight every time with this technique too. Without this teqnique I found myself aborting several times because I couldn’t run fast enough (with the added weight and without a hill) and the wing would fall over to one side or the other after running quite the distance just to get it all the way up above my head. It was quite frustrating!
Vid on ducted blades - though not sure how relavent to dual porps
I prefer the forward launch.
Hi Etiene, thanks for your inputs.
People always come up with new ideas, even if things are already working very well, there’s always room for innovations. It has always been like this.
“The main design flaw is that you can’t forward launch anymore.”: Why?! What’s the other design flaws?
“But the main concern is that this is not about design, it’s about calculations”. Calculations are the main part of a design. Are you talking about the concept?
“you may have way too much thrust with your setup. and too much thrust is a waste of energy (and weight)”.: This is a prototype and the more accurate thrust is going to be similuted using SolidWorks Flow. I use Autodesk Inventor and it doesn’t have that kind of simulation. A friend of mine is an aeronautical engineer and he will run the simulations for me, besides, thrust is easily controlled by the throttle.
It doesn’t take that much.
Not sure about the noise yet. We’ll see about that during the tests. Yes, the body is an obstruction, the RPM on the 2nd propellers will be higher than on the front ones. There’s no obstruction there, they’re going to work in conjunction.
No, they don’t. They are just protections. To have an improvement in efficiency, the shape of a ducted fan has to be very different.
So far I don’t see any reason the design would be a problem to launch, whichever way you decide.
They’re going to be carbon fiber.
Ducted regular propellers are not ideal. The best design is ducted fans, with particular shape, like the ones on turbofan jet airplanes, with 12 blades or more. Some EDFs have 5 blades, but they are noisier. The blades shape also has impact on the noise level.
Check this out:
Here’s an idea about the airflow simulation in SolidWorks.
The more I think about this idea, the more I think it’s great. The wings would fold/unfold by servos activated by the throttle or a torque controlled hinge to make a smooth transition that takes around 2 or 3 seconds to fully fold or unfold. The wings in folded position would reduce the drag quite considerably.
I am not liking it for foot launch so much as the weight sounds like it is adding up – but loving it for use on a trike configuration!
Awesome to see a pro version of what I tried to sketch last year (Assisted Free Flight)
I like your idea of using opposed motors for counter-rotating props, looks good. I got stuck on the shaft-within-shaft idea.
Folding for less drag is definitely a goal worth pursuing.
Your non pro version is way more pro than I could have done
Hi Mateo! I didn’t see your post before now. It’s cool we have the same concept in mind. I’m at work right now and I’ll read the whole topic at night and I’ll comment more. Cheers!