Very interesting thoughts and experiment. I hope towards the end of this year I will have Tensy V3 that will allow us to measure the tension on all lines on a paraglider on both sides. This would be one of the many experiments it would be worth doing and comparing results with.
I've been researching for a while, and while there are many great brands with solid ppgs, what you are doing for the community, through education, meetups, and adventures, has earned my money when I make my purchase.
Great video!! Very informative. I would love to see you run the same test on a Scout with the torque compensation to see the effectiveness of your design.
I really appreciate your science and disclosure of potential error in your numbers. This definitely earns trust. I truly love this series of videos. I successfully tweaked my low carb settings after your recent video with great success. I was having issues with my throttle before, and now she purrs. Thank you!
Love that you're making content like this! Given how dynamic torque compensation works, I'm interested to see the speed of the induced airflow from the propeller compared to the airflow from forward flight under different wings. I'm guessing that with DTC there is an optimum airspeed for each engine RPM to achieve neutral torque, but that High RPM + Low Airspeed = Clockwise Torque and Low RPM and High Airspeed = Anti-Clockwise Torque.
this was very interesting video .so far rather than simply taking the word from manufacturer of what the stock torque specified . With this information, now the pilot can actually measure the torque with different kind of propellers. awesome !
Many years ago the topic was how the torque affects the speed, blade depth and blade weight. it was not measured with paramotor but with electric helicopter rc. this had its own motor in the rear rotor. both engines were logged and saved via telemetry. so you could graphically evaluate the relationship between torque, speed, etc. in ecel. the rotor diameter was 125 cm so everything is very similar to ppg. I can tell you it is reflected very closely with your explanation. best regards
I am absolutely interested in these torque forces in flight. I am still experiencing significant torque with the scout-carbon on steep climb-out using a slow wing (25mph), though none of my buddies on faster wings feel any. I am curious if ambient air speed increases the effectiveness of the fins. I am pretty light so my climb angle is very steep at max thrust and consequently my air speed can sometimes be quite low when I need the most torque compensation. This is partially a separate discussion, but I'd love to see a load cell on the engine thrust during these tests as well. I suspect max thrust is very different between stationary and cruising speed. I recently got an E-prop 135cm as backup and was very disappointed with the mileage. I found on the ground it was very high thrust, but in flight it was very low load resulting in high cruise RPM poor climb, and 30% worse fuel/distance. I am curious if a less efficient (or smaller) propeller will have any meaningful impact on the torque compensation AT SPEED. Static thrust tests are not the right metric. Propeller properties and torque compensation are only meaningful in flight and should primarily be tuned to optimize in flight experience.
Miroslav, great information, thanks. These are torque measurements around the axis of the propeller. What would also be very interesting is to measure the "Gyroscopic effect" of a propeller that is pointing too far upwards or downwards (improper hang points) as you turn the SCOUT right or left, or as you increase/ decrease propeller RPM. It looks like that contributes to the cause of the accident shown at about 1:35 in your video. Again, fantastic series of educational videos, thanks!
The angle at which you put your feet on the car changes the vector in the vertical axis. It will still vary in real flight depending how many g’s you pull in your “level flight”. The best way to remove this variable is to attach the motor to a rigid structure in the forward and reverse axis which allows frictionless motion in the rotational axis
I think he did mentioned in this video it as 'Static Thrust' .I am sure in-flight thrust would vary based on varying heights (air density) , wind speed and other dynamic parameters.
Awesome video, looking forward to the next one. That being said, you might need to learn a little bit about rope & knot technology before trying something like that again. It looks like the rope stretching caused your accident. By the way, a simple overhand knot in a rope can reduce it's strength by half and it will break right there at the knot.
Hi Miro, first, thanks for yet another very interesting and informative video! Questions/suggestions though...Respectfully, to enhance the accuracy of your readings, wouldn't it be better to isolate the the torque in your readings by making sure that the propeller was vertical (90 degrees to the Normal force of gravity) at the time of measurement, as well as the ropes being completely vertical (as Voloshin Ivan already commented on, below)? Additionally, while I realize that putting your feet on the Suzuki was improvised during the experiment, wouldn't the grip/traction of your feet pressing against the car (vs. being on a pivot bearing) impact the accuracy of your torque readings, as your legs (however unintentional) would resist some of the torque? Thanks again for your sharing of your knowledge!
The angle of attack on the propeller profile decreases with increasing speed. As a result, the lift and the drag should both decrease. Less drag = less torque.
for the next following video, is it possible for you to put a weighing scale and measure thrust at different varying speeds ? I believe , that would be very informative
very informative and nice video! well done. with 2 pcs S-förmige Wägezelle S21N / log in 60hz with full telemetrie, power in watts / rpm in csv data loged as hobby pilot in austria :-) many things are done in the background. the comparison of low rpm ultra light propellers to standard ones is particularly interesting. just like when the center of gravity of the propeller blade is very close to the center. therefore modern thermal e-ppg can do without torque compensation due to their very low speed and ultralight propeller. with a very powerful high-speed petrol engine like the moster, yes, you will always need a solution when it comes to torque.
I love these videos! The one thing I found interesting was the readings when you were supported by the car and powered up was less than just hanging there. Shouldn’t one be more and one be less than the original. My thought would be by supporting with your feet and keeping level you are compensating for the torque slightly. This could possibly explain the weight differencePlease correct me if I’m not thinking straight haha.
I wonder if any other paramotor mfg goes through this extensive testing. Seriously doubt it! very interesting. I would imagine that actual numbers of torque will decrease at speed when forward speed affects aerodynamics.
I hope your back is fine. I believe different flight speeds at the same rpm will result in a different torque (less speed=more torque), for the same reason the effective trust in flight is less than the static trust (more speed=less trust)
Very interesting video. I Will also make my prediction for the next video for fun. 5500rpm it gives at 60% of the propeller length around 200m/s velocity. Speed of ppg around 11m/s. So I would say that angle of attack on the propeller will reduce(??) by 3° which is not negligible. I don't have curve of CD for Naca profile in front of my eyes but I would say that same rpm, torque will by smaller but it is just my rapid prediction and for sure I probably made a mistake 🤔. Let's see if I'm wrong in the next video. Nice video because I think it the best way to do engineering. Better than on a computer everyday like I do😜
Greate video. But I see one minor inaccuracy that should affect the reading. The ropes are not strictly vertical. They are actually angled. What tha means that: 1) The sum of the weights on left and right does not equal to the mass of the system. You would need to do some math to figure out the true mass. 2) I would expect that the sum of the readings change (as you observed) when torque is applied to some degree. The reason for that in my opinion: the torque will change the angle of these ropes. One rope will become closer to vertical. Another - more tilted. Since the relationship between mass, indicated tension/weight and rope angle is nonlinear - I would expect the summ of the two to change slightly. 3) To properly estimage the torque you need to take into account the angle of the ropes. It doesn't look from the video that you did that. Eyeballing it from the video it seems like angle of a rope is about 30 deg. If my napkin math is correct, that would mean the indicated readings are inflated by 1/cos(30deg). Which is about +16 percent. So the real torque will be 16% lower. Take this math with a grain of salt. I didn't really sit down to make sure it's correct. But I guess, the main point I wanted to make: for accuracy the angle of the rope should be taken into account.
Hi, thanks for sharing, great video! If the level fligth torque is 8.5Nm and the prop spins 1837 rpm, this gives approximately 1635W power. Sounds a bit low /only 2.1Hp/ can this be correct or I made a failure in my calculations?
@@SCOUTaviation yes but i think the torque steer is approximately equal with the torque of the propeller. So we know the torque on the propeller shaft that is 8.5Nm. The propeller is rotating approx 1830rpm. So we can calculate the power / Power = Torque x angular velocity/. And with this formula comes out 1600W power for the propeller. Greetings, Roland Falusi
@@SCOUTaviation maybe because the pilots body COG is under the rotational axis, this counteracts the propellers tourqe. At least a part of the torque is eliminated this way.
Engine torque translates to engine power. Engine power delivered to the prop is then converted into thrust and torque. Not sure, but it's seems you calculated the horsepower value of the torque component. The prop thrust is missing. Thrust could be calculated from side view measuring the angle to which the prop had pushed me forward and calculating my weight. I actually did that too but it would make the video too long
@@SCOUTaviation i think the system "doesnt see" this components. Simple there is tourqe on the propeller shaft by a given rpm. The tourqe cause the rotating of the pilots body and this is what you measured. I think by my calculation is missing the movement by the rotation: torque is twisting your body and because the center of gravity is lower as the rotational axis, there will be a counter torque because the pilot mass.
Great! Now put a bearing on the axle of the prop, so on the rear, connect a cable to the bearing and to some heavy object (car), and use that to keep the paramotor at the same place. This way you don't have to use your legs. Edit: typo
Hang on. No torque compensation is dangerous? Can we talk about how many paramotor frames do NOT have torque compensation? My torque compensation is letting out the left trim a bit more past neutral than my right trim. I have not yet died or twisted. I think "less ideal" is a more accurate statement than "dangerous," so long as the pilot understands what it is and how to manage it.
@@SCOUTaviation 2016 Vittorazi Moster 185 Dark Evolution on a "Simple Frame" made by SkyCruiser Manufacturing in Sauk Rapids, MN -- skycruisermfg.com/ -- with an APCO harness. Doesn't look like they have that frame for sale on their site anymore. Fixed J-bars, 17L tank. Aluminum struts, net. Literally simple! The way that the motor is mounted (I purchased this from my instructor) may have compensated for torque, but I was also taught to modify my trims slightly to compensate.
I think he meant that a Scout without fins is useless. All paramotors need some form of Torque Compensation built into the frame, but because the Scout uses the aerodynamic fins, it doesn't have other features like offset bars or cross straps, so the test rig with round tubes would be pretty sketchy to fly.
Thanks Harry for explaining. Yes, correct. No way I am trying to bash other brands. I believe every paramotor that gets you in the air safely is a good paramotor. Such an amazing sport.
Thats they way it come across yess you have a good concept there and its proven to work and work well but down grading others to benefit your self wouldn't be cool glad uve replied and cleared that up
Very interesting thoughts and experiment. I hope towards the end of this year I will have Tensy V3 that will allow us to measure the tension on all lines on a paraglider on both sides. This would be one of the many experiments it would be worth doing and comparing results with.
I've been researching for a while, and while there are many great brands with solid ppgs, what you are doing for the community, through education, meetups, and adventures, has earned my money when I make my purchase.
That's why I also bought a Scout Enduro.
You always make the greatest explainer videos. Thanks for all of the work you do educating this community.
Respect for what’s doing.
Great video, great work!!
Great work Miroslav!
Great video!! Very informative. I would love to see you run the same test on a Scout with the torque compensation to see the effectiveness of your design.
...coming out soon :P
I really appreciate your science and disclosure of potential error in your numbers. This definitely earns trust. I truly love this series of videos. I successfully tweaked my low carb settings after your recent video with great success. I was having issues with my throttle before, and now she purrs. Thank you!
Love that you're making content like this! Given how dynamic torque compensation works, I'm interested to see the speed of the induced airflow from the propeller compared to the airflow from forward flight under different wings. I'm guessing that with DTC there is an optimum airspeed for each engine RPM to achieve neutral torque, but that High RPM + Low Airspeed = Clockwise Torque and Low RPM and High Airspeed = Anti-Clockwise Torque.
I hope all paramotor pilots get the chance to meet Miro in person. The dude is super smart and fun to chat with.
this was very interesting video .so far rather than simply taking the word from manufacturer of what the stock torque specified . With this information, now the pilot can actually measure the torque with different kind of propellers. awesome !
Many years ago the topic was how the torque affects the speed, blade depth and blade weight. it was not measured with paramotor but with electric helicopter rc. this had its own motor in the rear rotor. both engines were logged and saved via telemetry. so you could graphically evaluate the relationship between torque, speed, etc. in ecel. the rotor diameter was 125 cm so everything is very similar to ppg. I can tell you it is reflected very closely with your explanation. best regards
I am absolutely interested in these torque forces in flight. I am still experiencing significant torque with the scout-carbon on steep climb-out using a slow wing (25mph), though none of my buddies on faster wings feel any. I am curious if ambient air speed increases the effectiveness of the fins. I am pretty light so my climb angle is very steep at max thrust and consequently my air speed can sometimes be quite low when I need the most torque compensation.
This is partially a separate discussion, but I'd love to see a load cell on the engine thrust during these tests as well. I suspect max thrust is very different between stationary and cruising speed. I recently got an E-prop 135cm as backup and was very disappointed with the mileage. I found on the ground it was very high thrust, but in flight it was very low load resulting in high cruise RPM poor climb, and 30% worse fuel/distance. I am curious if a less efficient (or smaller) propeller will have any meaningful impact on the torque compensation AT SPEED.
Static thrust tests are not the right metric. Propeller properties and torque compensation are only meaningful in flight and should primarily be tuned to optimize in flight experience.
The third video in the series will give your answers...
This is excellent Miro!
Miroslav, great information, thanks. These are torque measurements around the axis of the propeller. What would also be very interesting is to measure the "Gyroscopic effect" of a propeller that is pointing too far upwards or downwards (improper hang points) as you turn the SCOUT right or left, or as you increase/ decrease propeller RPM. It looks like that contributes to the cause of the accident shown at about 1:35 in your video. Again, fantastic series of educational videos, thanks!
Your are right!
I will think of how to measure it.
The angle at which you put your feet on the car changes the vector in the vertical axis. It will still vary in real flight depending how many g’s you pull in your “level flight”. The best way to remove this variable is to attach the motor to a rigid structure in the forward and reverse axis which allows frictionless motion in the rotational axis
I think he did mentioned in this video it as 'Static Thrust' .I am sure in-flight thrust would vary based on varying heights (air density) , wind speed and other dynamic parameters.
Awesome video, looking forward to the next one. That being said, you might need to learn a little bit about rope & knot technology before trying something like that again. It looks like the rope stretching caused your accident. By the way, a simple overhand knot in a rope can reduce it's strength by half and it will break right there at the knot.
Very interesting and educational, thank you 👍
Hi Miro, first, thanks for yet another very interesting and informative video! Questions/suggestions though...Respectfully, to enhance the accuracy of your readings, wouldn't it be better to isolate the the torque in your readings by making sure that the propeller was vertical (90 degrees to the Normal force of gravity) at the time of measurement, as well as the ropes being completely vertical (as Voloshin Ivan already commented on, below)? Additionally, while I realize that putting your feet on the Suzuki was improvised during the experiment, wouldn't the grip/traction of your feet pressing against the car (vs. being on a pivot bearing) impact the accuracy of your torque readings, as your legs (however unintentional) would resist some of the torque? Thanks again for your sharing of your knowledge!
The angle of attack on the propeller profile decreases with increasing speed. As a result, the lift and the drag should both decrease. Less drag = less torque.
Correct. This is the reason we need to go in the air.
The video is in edit already.
for the next following video, is it possible for you to put a weighing scale and measure thrust at different varying speeds ? I believe , that would be very informative
Great video again Milo, but I'm not going to make any predictions on the probable effects when actually flying and with different wings...
very informative and nice video! well done.
with 2 pcs S-förmige Wägezelle
S21N / log in 60hz with full telemetrie, power in watts / rpm in csv data loged as hobby pilot in austria :-) many things are done in the background. the comparison of low rpm ultra light propellers to standard ones is particularly interesting. just like when the center of gravity of the propeller blade is very close to the center. therefore modern thermal e-ppg can do without torque compensation due to their very low speed and ultralight propeller. with a very powerful high-speed petrol engine like the moster, yes, you will always need a solution when it comes to torque.
I love these videos! The one thing I found interesting was the readings when you were supported by the car and powered up was less than just hanging there. Shouldn’t one be more and one be less than the original. My thought would be by supporting with your feet and keeping level you are compensating for the torque slightly. This could possibly explain the weight differencePlease correct me if I’m not thinking straight haha.
I was hoping to see the Scout torque compensating machine in this test, to verify the two KG values would be similar throughout the different RPMs.
Wait for the third video in this series. We were shooting some clips for our yesterday
I wonder if any other paramotor mfg goes through this extensive testing. Seriously doubt it! very interesting. I would imagine that actual numbers of torque will decrease at speed when forward speed affects aerodynamics.
I hope your back is fine. I believe different flight speeds at the same rpm will result in a different torque (less speed=more torque), for the same reason the effective trust in flight is less than the static trust (more speed=less trust)
Very interesting video.
I Will also make my prediction for the next video for fun.
5500rpm it gives at 60% of the propeller length around 200m/s velocity. Speed of ppg around 11m/s.
So I would say that angle of attack on the propeller will reduce(??) by 3° which is not negligible.
I don't have curve of CD for Naca profile in front of my eyes but I would say that same rpm, torque will by smaller but it is just my rapid prediction and for sure I probably made a mistake 🤔. Let's see if I'm wrong in the next video.
Nice video because I think it the best way to do engineering. Better than on a computer everyday like I do😜
If the thrustline of the propellor is not exactly 90 degrees to your risers would that not change the total weight on the two scales ???
Greate video. But I see one minor inaccuracy that should affect the reading. The ropes are not strictly vertical. They are actually angled. What tha means that:
1) The sum of the weights on left and right does not equal to the mass of the system. You would need to do some math to figure out the true mass.
2) I would expect that the sum of the readings change (as you observed) when torque is applied to some degree. The reason for that in my opinion: the torque will change the angle of these ropes. One rope will become closer to vertical. Another - more tilted. Since the relationship between mass, indicated tension/weight and rope angle is nonlinear - I would expect the summ of the two to change slightly.
3) To properly estimage the torque you need to take into account the angle of the ropes. It doesn't look from the video that you did that. Eyeballing it from the video it seems like angle of a rope is about 30 deg. If my napkin math is correct, that would mean the indicated readings are inflated by 1/cos(30deg). Which is about +16 percent. So the real torque will be 16% lower.
Take this math with a grain of salt. I didn't really sit down to make sure it's correct. But I guess, the main point I wanted to make: for accuracy the angle of the rope should be taken into account.
Hi, thanks for sharing, great video! If the level fligth torque is 8.5Nm and the prop spins 1837 rpm, this gives approximately 1635W power. Sounds a bit low /only 2.1Hp/ can this be correct or I made a failure in my calculations?
We did not measure torque of the engine. We measure torque steer of the propeller
@@SCOUTaviation yes but i think the torque steer is approximately equal with the torque of the propeller. So we know the torque on the propeller shaft that is 8.5Nm. The propeller is rotating approx 1830rpm. So we can calculate the power / Power = Torque x angular velocity/. And with this formula comes out 1600W power for the propeller. Greetings, Roland Falusi
@@SCOUTaviation maybe because the pilots body COG is under the rotational axis, this counteracts the propellers tourqe. At least a part of the torque is eliminated this way.
Engine torque translates to engine power. Engine power delivered to the prop is then converted into thrust and torque. Not sure, but it's seems you calculated the horsepower value of the torque component. The prop thrust is missing.
Thrust could be calculated from side view measuring the angle to which the prop had pushed me forward and calculating my weight. I actually did that too but it would make the video too long
@@SCOUTaviation i think the system "doesnt see" this components. Simple there is tourqe on the propeller shaft by a given rpm. The tourqe cause the rotating of the pilots body and this is what you measured. I think by my calculation is missing the movement by the rotation: torque is twisting your body and because the center of gravity is lower as the rotational axis, there will be a counter torque because the pilot mass.
Kinetic engine possibilities
Great! Now put a bearing on the axle of the prop, so on the rear, connect a cable to the bearing and to some heavy object (car), and use that to keep the paramotor at the same place. This way you don't have to use your legs.
Edit: typo
Yes that would be correct. Originally we did not expect it to be so unstable. So the little suzuki was a quick improvisation on the spot.
Did you bust it?
The stand was trashed, and one carbon part. We fixed another with carbon patch.
Hang on. No torque compensation is dangerous? Can we talk about how many paramotor frames do NOT have torque compensation? My torque compensation is letting out the left trim a bit more past neutral than my right trim. I have not yet died or twisted. I think "less ideal" is a more accurate statement than "dangerous," so long as the pilot understands what it is and how to manage it.
All paramotors have some sort of compensation. What kind of paramotor do you have?
@@SCOUTaviation 2016 Vittorazi Moster 185 Dark Evolution on a "Simple Frame" made by SkyCruiser Manufacturing in Sauk Rapids, MN -- skycruisermfg.com/ -- with an APCO harness.
Doesn't look like they have that frame for sale on their site anymore. Fixed J-bars, 17L tank. Aluminum struts, net. Literally simple! The way that the motor is mounted (I purchased this from my instructor) may have compensated for torque, but I was also taught to modify my trims slightly to compensate.
My opinion is that you look much younger with longer hair lol.
Because I was much younger when I had long hair :-)
Don’t do this in the air. Just be smarter with the science used on the ground
Starting to sound like super dell by basically saying paramotors with out torque fins are useless
I think he meant that a Scout without fins is useless. All paramotors need some form of Torque Compensation built into the frame, but because the Scout uses the aerodynamic fins, it doesn't have other features like offset bars or cross straps, so the test rig with round tubes would be pretty sketchy to fly.
Thanks Harry for explaining. Yes, correct. No way I am trying to bash other brands. I believe every paramotor that gets you in the air safely is a good paramotor. Such an amazing sport.
Thats they way it come across yess you have a good concept there and its proven to work and work well but down grading others to benefit your self wouldn't be cool glad uve replied and cleared that up