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Thrust issues


tomarnold
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I have recently started flying paramotors after freeflying for 7-8 years. I have flown 5 hours in the last month and am loving it! However, I have started noticing a slight climb-rate problem. I fly a fairly elderly Rad Arrow (with the Radne Raket 120 engine) and a Revolution 26. I weigh 73kg so am at the bottom-middle of the wing's weight range.

I have started to notice that I can't climb very quickly (didn't notice that much early on as I was getting used to flying under power). I know that the Raket engine is pretty low-power, but they claim 50kg thrust and a climb rate of 1000ft in 5 minutes under ideal conditions. I have found that it is taking me more like 15 minutes to climb to 1000ft, and even slightly longer if there is sinky air about.

When I am warming up the engine it will reach the 9600rpm that is quoted in the manual, but then when in the air it won't rise above 9100rpm. Is that normal, or should I expect to see the 9600rpm max while flying the same is I do on the ground?

I'm not really sure where to start with regards to sorting this out. I guess I could start with stripping down the carburettor (never done that before, but everybody's gotta start somewhere) and cleaning it up and replace the gaskets. Any other ideas?

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Hi , check belt tension my its skidding , what sizes prop? your carburettor its ok if you turn 9600rpm .

I have 9900rpm but in the air just 9400-9600rpm this is normal.

Just one question ,who told you about 1000' (300 meters up)in 5min with radne racket engine??? i think its a dream ,you need 25HP motor to try keep up speed of ascending 1000' in 5min

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Thanks for the replies guys.

I'll check the belt tension and give the carb a good cleanout.

The 1000ft in 5 mins was on the Rad paramotors website, so perhaps it's a bit of an optimistic claim!

Perhaps I'm simply affected by the fact that in my years of paragliding I've been used to climbing at 1000ft/min in thermals, so to take 15 minutes to get up to 1000ft feels pretty slow!

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I seem to remember having to have a load of right brake on when flying my Rad :-(

That was what I found amazing when moving over to low hang point.... almost 0 torque steer, and some (but nothing like free flight) weight shift ability.

PG pilots always seem to go for the Rad as the first motor because of the weight and price but it is very much a case of you get what you pay for an things are much much better now than the 15 year old design that is the Rad.

Sorry if that hurts :-( :-(

I had loads of fun on my Rad (some of my best flying years in fact!) and it is a great machine for low budget pilots (because it works) but I would never go back to one.

SW :D

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They claim 50kg thrust :lol: In perfect conditions,A perfectly tunned new engine On a Thrust test machine...

Not an old motor in hot and humid conditions it will always be down on power. Time for a new machine!! :wink:

I am 75kg and fly a smallish 24m speedster on a V5 (Claimed 60kg) i can climb at 200-220 fpm on full trim. 400ish on slow (just for a comparison) On my moster zenith i can climb 600fpm+ on a 20m GTR. :D

Regards

Mark

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Sounds like I'll just have to be happy that I can get in the air and put up with a slow climb rate. Fair enough.

I like the sound of a newer machine but I saved up for years to pay the £700 for my motor, so there's no way I'll be getting a new one for many years to come!

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tomarnold I dont know whay they claim 50kg thrust,but with standard exhaust like from them on the photo,you can get it just 14HP max and 35-40kg thrust.

I personally tuned my raket 120 up to limit 19.5HP

if you want more power you need invest in new expansion chamber (proper one give you 3-4HP more),new gear 1:3.6 or 1:4 with good matched propeller 125 or 130cm +tuned engine and carb

If you can do it your self its worth it,other ways Im not sure .

costs about 400£ +cost new propeller

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:wink: hey morgy my point is just for training purpose ,of course is not worth :lol: ,but many people who against normal logic thinking would like to do it themselves,not watching cost, for their own satisfaction :mrgreen:

sorry but I dont believe you can find old more powerful unit for 1500£ ,unless is weighs 30-40kg

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:wink: hey morgy my point is just for training purpose ,of course is not worth :lol: ,but many people who against normal logic thinking would like to do it themselves,not watching cost, for their own satisfaction :mrgreen:

sorry but I dont believe you can find old more powerful unit for 1500£ ,unless is weighs 30-40kg

old top 80.

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  • 3 weeks later...

help needed

I wont to use the raket 120 engine for a Paramotor but where do you find out the added power in crease by using the tuned exhaust and tuned barrel and piston etc.

is there some were that supplies this info

would like to know what thrust would you get out of standard unit 14.5 horse power 130 cm prop 3 blade and best ratio to use

please can someone point me in the right direction

I am 95 kg and the raket engine is cheep and lite

I can make Paramotor under 20 kg

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How do you check that Pete -on the wall?

here you have test top 80 vs raket 120

two motor are standard -not tuned

and compare few motors

6:40min standard radne raket 120 with 130 cm prop. weight only 18.1kg(no fuel)13:30min

9:20min miniplane top 80 with 125 prop 45kg thrust max -full tuned.

all motors had stable thrust

210 solo I have few links tuning radne raket 120 but in Polish if you want i can send you for priv.

Edited by Guest
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How do you check that Pete -on the wall?

here you have test top 80 vs raket 120

two motor are standard -not tuned

and compare few motors

6:40min standard radne raket 120 with 130 cm prop. weight only 18.1kg(no fuel)13:30min

9:20min miniplane top 80 with 125 prop 45kg thrust max -full tuned.

all motors had stable thrust

210 solo I have few links tuning radne raket 120 but in Polish if you want i can send you for priv.

On a proper thrust tester at a flyin a few years ago my pap top 80 125 wood prop1400 50-55 Pap top 80 1200 100 wood prop was giving 45-50

These were both pap machines not miniplane so not sure if they do anything to the engine.

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