Paramotor gets terrible thrust

I recently thrust tested my open ppg paramotor. I only got 80lb thrust. Just to check the thrust tester we then put a paramotor with an engine equivalent to a vittorazi 185 and it tested at over 135lb thrust. We were testing these at over 4500 feet altitude, but I thought that would give the open ppg a thrust advantage over the gas paramotor.

How was your test conducted?

Is this your ePPG?

If you have the Dualski G6000 motors you would need 24x10 props to have the same thrust as
the OpenPpg X4. The OpenPpg has a 150 cm cage to accommodate 22x10 props with the
KV 180 and KV 150 motors.
What props are you using?

the maximum thrust that can be achieved with 24/10 propellers and an input power of 15 kilowatts is around 120 lbs. nothing more is physically possible. regardless of which motors are used.

I’m currently using 22x10 xoar props. Also yes, that is the eppg I built.

Exactly, with 15 kw you will reach only 120 lbs thrust in real life even with a single prop setup!
Maybe without cage you can reach better thrust numbers. We need real world thrust stand numbers and not bench numbers.
As I mentioned before, one member in GB was on a real thrust stand and with
the current OpenPPG X4 had 130 lbs thrust with 4 motors = 18.8 KW total. The Paracell Simplify single prop with 19 KW motor was tested on a thrust stand with 127 lbs thrust as tested in a german test magazine.
OpenPPG 949

These are facts.

I still believe that if you are under 85 kg pilot weight you need only 120 lbs thrust.
So for Bob27 to have 120 lbs thrust he can use 24 x10 props as specified by the motor manufacturer.
His motors with 22 x10 produce now only 80 lbs trust. He can use 2 new version standoffs and fly with
overlapping props. But still his cage will maybe to small to cover 24 inch props. He has to find the
correct combination for his motors. The OpenPPG X4 has more powerful motors and needs a
different prop combination.

My open ppg has pushed me off my feet during a thrust test.


I’ll bet. Under full power climb in seeing only 240amps with my batch 4 running six cell batts (12s). That translates to around 10kw, which would be only 80lbs thrust. My all up weight is just over 100kg and the climb is good enough.

I must ask. Are you taking off at over 5000’ elevation. I haven’t even flown yet, but my future instructor said that 80lb thrust at our altitude will barley get me off the ground in a reasonable amount of space. My instructor is unique because he trains students to fly on smaller wings for better performance while still having the safety on an A certified wing… But you need more thrust to take off in a reasonable amount of space.

Oh no. I’m basically at sea level. Wing is a Buzz Z3ML 22 meters.

Why not fly a bigger wing? At 5000’ drag and lift are both reduced for a given wing at a given air speed. Increase the wing to bring the drag and lift up, or increase propeller pitch to increase airspeed. The latter option will mean running faster to launch. Running faster at 5000’ doesn’t sound like fun. A smaller wing would mean even faster running yet.

I thought flying at higher altitude should require less total power. That’s why airliners fly so high -to save fuel.

you can see the truth at the airfield :slight_smile:

It actually requires more power at higher altitudes to stay flying. But for the same amount of power used you can fly a lot faster and cover more distance. For my weight I will probably fly either an xxs or a xxxs wing size. We do fly small wings but due to the very high cell count of the wing combined with a low aspect ratio they do get a very high lift for there size. So my instructor has no problem launching an xxxxs or 16m² wing in no wind… But it’s not necessary fun to. The biggest thing is that with smaller and safer wings we can fly in a lot more weather conditions without problems.

Bob you have a very old unit one of the first. The fist thing I would look at is the props and kv setup you have. The props don’t look like the gemfans we use right now, they are just more efficient so probably a worth while upgrade.

The other big thing is the batteries it looks like your using. Aside from being old those multistar 6s 10c 16ah batteries don’t really have the continuous output power you would want. In general I like to have 2-3x the c rating I think I need. The Batts you are using have very low discharge ratting and along with being old that will create a lot of voltage sag and your thrust will not be what it could be. I would look at the voltage when you go full throttle on the thrust stand and let us know what you get.

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I think even if I do end up getting the thrust I want it still won’t give me the flight time I would like. At this point I think that I will just going to sell it and make my own version of your sp140 on the frame that I like.

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Yes a higher wing loading will keep things smoother in more turbulent conditions for sure. You’re just flying faster relative to the wind changes. Noticed that with model airplanes when I was flying them.

Yup smoother when turbulent, the higher wing loading helps with faster collapse recovery and makes it harder to collapse. Improved airspeed for flying in higher winds. Lots of advantageous.

Plus the glider he likes best has a very high cell count which gives a more precise airfoil so he can out glide almost any wing of the same size. Finally because his preferred glider doesn’t have a very high aspect ratio it has low frontal area which gives lower drag at high speeds. So he has gone over 50mph airspeed with the 14meter² version of this wing.

While your instructor may have convinced you having a smaller wing is better and safer, essentially what you’re saying is you’re learning to fly on a slalom wing most probably outside of the manufacturer’s weight rating, if it’s even rated. It will always be less safe to launch and land (the most dangerous times) because you’ll be going a lot faster. It will also be a lot easier/faster to get into trouble. Whilst it may be true it’s better/safer in turbulence, beginners don’t fly in turbulence.

bob: with which engine does he fly a 14 m2 wing 50 mph?

He actually uses custom cloth, lines, and has them built to handle extra load, he doesn’t just overload a wing. Also yes, It is true beginners should stay away from turbulence.

He was either using his vittorazi 185 or modified simonini. I’ll need to check.