Surging on take off

[gavdo]

Hi

need some advice. The last couple of times that i have been up flying i have been experiencing a few difficulties on take off.

I fly a Paravis Jazz with an old RAD paramotor RXL style solid cage.

In early take off before sitting in the chair i am experiencing a lot of surging combined with slow climb rate. once in the chair all seems well (although a bit better climb would not go amiss) and i can fly about as usual. Without having spectators it is hard to identify what the problem is. I have tried to adjust the hang angle whilst standing in take of position and have been very careful to learn back to a suitable angle to make sure the thrust line is good, but it is still surging. I have always been told to use full power on my take off especially due to the little rad's thrust capabilities but i am wondering if i should try to back it off a bit?

Other ideas or reason?;

1, to much thrust causing near stalls

2, engine not producing full power (it is running a little rich)

3, badly set up hang position. ( does anybody know or can demonstrate visually optimum postitioning for rad harness) on ground and in air.

4, props although not damaged are probably due for renewal

please feel free to advise or suggest other ideas to help, especially if you have experienced simular problems.

regards

Gavin

[Guest]

what is "surging"

engine revs going high?

or wing coming forwards of you then falling behind and coming forward again?

Is this a problem that has developed but used to be OK or are you new to this combination?

[gavdo]

sorry for long time to respond but been a bit busy of late.

The problem seems to have developed ever since i put a new engine on. Personally i think that the engine is over reving but i am not sure. I wanted to guage other peoples responces / suggestions.

although i dont feel asthough i am approaching a stall on take off the wing is behaving in a way that suggests otherwise. initial climb once air bourne is slow, very slow (whist still hanging). The most puzzeling thing is the way that these syptoms seems to clear once i am in the seat this is what makes me think it is related to bad setup. But no one or books seem to go in to much detail on setup (harness setup).

If you would like to shed some light please let me know.

regards

Gavin

[Guest]

I have to ask.....

Have you carried out a hang point check? if not it may be a good idea to do so...

You may find that your motors thrust line is pointing towards the ground a little to much.....

If not, it will still help to eliminate your problem

SW

[gavdo]

I have done a couple of hang tests and i keep on readjusting it. The poroblrm is that i am not sure exactly when it is right, how do i know what is right. When I hang tests whilst standing, holding all the weight, the thrust line points up with a good lean back it looks about right. when the wing takes the weight and i am just hanging from the harness the thrust line looks pretty straight. Once in the chair the engine seems to hang back with the thrust line pointing approx 30 degree towards the groud although it is hard to tell.

If you can give me any tips on what to look for or how to hang correctly this would be great the old paramotor bible does not really go in to much detail.

thanks for your help simon

regards

Gavin

[gavdo]

Hi Simon

I actually had the chance to go flying on friday and decided to adjust the harness again before going airbourn. A quick guestimate on settings and a brief hang test. Then for the test in a nill wind forward. All went well. Climb out good, torque good, even managed to get in to the notoriously bad old standard rad harness with ease. In flight the climb rate was better aswell. Thank you for your help, I am sure that i can close this message board of now. Problem Solved

Gav

[Guest]

Great!

SW