I plan on using the dle 55ra engine to produce 5hp at 8,500 rpm. I am using it in a paramotor, and to save space I am considering using a ducted propeller similar to the Fulcrum power pod. The duct intake would have to be directly behind my back, so I plan to add around 6 inches of space to allow air intake. The engine would be mounted on my back facing into the intake. Effectively, it would be a normal paramotor with a duct around the fan blades. My estimated duct wall clearance is 1 or less mm. I need to produce 15kg of thrust, so how would I design this fan? I considered using a heating duct, which is an 18-16 reducer. This would allow me to get some benefits of the thrust tube and would make it easy to have a front-mounted propeller. Would this propeller work? It is 18x7"

TLDR: Would my combination of propeller, duct and engine produce 15kg of thrust.

Thank you!

  • $\begingroup$ Paramotors require at minimum 125lbs of thrust to have any kind of performance for climb. Most are around 140-175 lbs. 35lbs won't even get you off the ground. $\endgroup$
    – John K
    Commented Dec 5, 2022 at 6:04
  • $\begingroup$ @GregHewgill It's a paramotor question. Paramotors are airplanes. $\endgroup$
    – John K
    Commented Dec 5, 2022 at 6:05
  • $\begingroup$ @John K, I don’t think I mentioned this in the question, however in a separate post other users helped me calculate that 5hp was enough to get 82kg full weight in the air, with some extra leftover.p(~2.5 extra hp). If my wing has a glide ratio of 7:1, then 82/7= 11.7143kg required for level flight. The approximately 3kg of thrust left would be for climbing. Would I need more? 20kg of thrust in total would probably be good. $\endgroup$
    – Lelotz
    Commented Dec 5, 2022 at 7:10
  • $\begingroup$ +Lelotz I already factored in climb ratio, as me and my setup weighs 64kg now, and I am accounting for future weight gain. 64/7=9.1429, so 15 is more than enough $\endgroup$
    – Lelotz
    Commented Dec 5, 2022 at 7:41
  • 1
    $\begingroup$ @JohnK: My apologies, I did not read the question carefully enough. $\endgroup$ Commented Dec 5, 2022 at 20:52


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