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Measuring thrust


matt_k
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My friend Gavin who is starting a Paramotor Repairs business has just built a Paramotor Thrust Checking frame...

Basically a frame where you mount the paramotor which slides a slight distance onto a meter which tells you how much force is being applied....

It's being tested, but if you are interested, he'd love to have volunteers.

He's in Surrey, so if you want, give me a PM and I'll get him in contact with you.

Cheers

Steve

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There is a way to measure thrust at home.

Do this against a brick wall.

With the motor on your back, hold some bathroom scales at arms length (keeping your arms as straight as possible) and power up. It's not the most accurate way of measuring thrust but it will give you a good idea.

Joe

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Hi Matt

The bathroom scales idea is excellent for a ballpark figure.

Jim Carolan and Michael (AKA Jabba) based around Alconbury also have a purpose built thrust tester.

Not sure how close that is to you.

I put my MXL on their machine and got 33kgs but I have seen examples get up to 36kgs.

Cheers

Steve

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Hi Matt

The bathroom scales idea is excellent for a ballpark figure.

Jim Carolan and Michael (AKA Jabba) based around Alconbury also have a purpose built thrust tester.

Not sure how close that is to you.

I put my MXL on their machine and got 33kgs but I have seen examples get up to 36kgs.

Cheers

Steve

A few years ago whilst at a fly in at a venue in France we were all testing out motors on Jim Carolan home made test bed, (the bullshit buster). lots of engines were tested on the same test bed in the same conditions. I remember a few from that day as follows.

My H&E 120 gave a 47kg readout

Parajet Volution (medium size one) 46kg.

Small Pap 80,s were nearly as much as my H&E about 43kg.

Black Devil gave about 65kg thrust and was the only machine that delivered anything like the manufacturers claims. I can't remember any others.

It would be a good thing to repeat and record.

An interesting phenomenon was discovered. While everyone crowded arround the harness side of the cage blocking the incoming airflow (sucking), thrust on the bullshit buster increased. I think this occured because a negative pressure built up between the crowd and the scales sucking the motor onto the scales as apposed to the thrust pushing harder.

Unfortunately many thrust and fuel economy claims are not accurate.

Regards.

Whitters.

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I was surprised how much uplift i got on my Rad, i wasnt revving that hard and the winds were very light and i went straight up.

May be the size of my wing (arcus swing 29m)and only being 62kg helps.

Would a revolution 26 be ok with the rad if i kept trimmers in? till i can afford a thrustier motor?

Great flying from two tree, been taking off from there low then heading out to sea at lowtide,

What about you come down one day Simon with a few others?

Matt

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Hi Matt

In my opinion I cant really see the point of switching from an Arcus 29 to a Revo 26 if you are unable to use the trimmers.

It's only with the trimmers out that the reflex kicks in and the speed picks up.

I would suggest using whatever finances you have available to upgrade your motor.

Another option along these lines might be to contact Paul Haxby at AXB Sports about his upgrade for the Raket engine you already have.

He can supply a new frame and prop which would boost thrust considerably and open your options much wider on wing choice.

Cheers

Steve

I was surprised how much uplift i got on my Rad, i wasnt revving that hard and the winds were very light and i went straight up.

May be the size of my wing (arcus swing 29m)and only being 62kg helps.

Would a revolution 26 be ok with the rad if i kept trimmers in? till i can afford a thrustier motor?

Great flying from two tree, been taking off from there low then heading out to sea at lowtide,

What about you come down one day Simon with a few others?

Matt

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  • 1 month later...

I have several props that I want to test to see which performs best. I was thinking about static thrust tests, but my thoughts are that; when in flight you are moving through the air mass so air flows into the prop turbo charging it. So it is likely that the prop that gives the most static thrust may not be the best in flight, I would expect a higher pitched prop to give more thrust in flight. In which case the best way to test will be to measure climb rates with different props.

Any comments, anyone have experience of this?

Steve, - I would like to volunteer to test your mates Thrust tester, i would like to do static thrust tests, and compare the results to climb rate tests.

Paul D

My friend Gavin who is starting a Paramotor Repairs business has just built a Paramotor Thrust Checking frame...

Basically a frame where you mount the paramotor which slides a slight distance onto a meter which tells you how much force is being applied....

It's being tested, but if you are interested, he'd love to have volunteers.

He's in Surrey, so if you want, give me a PM and I'll get him in contact with you.

Cheers

Steve

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  • 2 weeks later...

Since reading the post on bathroom scales I've been wanting to have a go and this mornings dodgy weather gave the perfect opportunity to test my Adventure A3+ against the new Parajet Cyclone 294.

I weighed myself on the scales before hand and they appeared to be weighing between 5-10kg light so bearing this and the many other inaccuracies of the test, I was more interested in the difference of the engines than any accurate reading.

I wasn't disappointed by the results. I always thought the A3+ was quite a powerful machine getting my (95kg) off the ground successfully for the last 2 years but the Cyclone is something else.

[youtubevideo]http://www.youtube.com/watch?v=P4qFoVeAa5s[/youtubevideo]

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