Ultralight Paramotor Development

[chieftan]

There must be a few paramotoring manufacturers missing a trick. I fly a PAP Top 80 and would gladly lose my 400f/min full throttle climbs for an ultra-compact and super light unit that develops enough thrust for launch (I rarely use full throttle!) and for max 100f/min climbs. The idea being that the unit could be intergrated or developed around free flying and the better handling characteristics would allow higher profile, more efficient wings to be flown. I would love to try my Rebel on power but find my motor far to cumbersome to have any real attempt at thermalling. If it were developed to be suitable for more experienced flyers then the cage could be made out of plastic and other weight saving methods used as practicle. Less fuel too. Any suggestions.

[Guest]

been thinking the same myself. Take a look at the www.aigate.cz machine, not that it is very light but look at the harness and the flying position. i would like to see that idea in a very light unit, as you say not much power neede just enough to get to a thousand feet or so, into the thermals where they are well formed. Maybe an electric powered one with just enough charge to give you 2 or 3 lifts?

Also if you take off from a little slope then power up you would not need the cage at all. A folding prop that you dont start until the wing is inflated and flying. ???

[spider]

The paramotor in this youtube video looks amazingly light (compared to my Parajet anyway)

Ain't got a clue what it is though, apart from being Japanese, as stated in another video.

Regards,

Geoff

[chieftan]

Thanks guys, there isn't anything on the market that appeals to me so I might have a look into building something myself (no experience and niaive ) Does anyone have any ideas what the smallest engine could be used (what about a Stihl chainsaw engine and its sprag clutch) at 46cm2 it produces 3.6bhp and 2.4kw of useable power. My GCSE calcualtions suggest that I would only need 1.6kw to maintain straigt and level flight (don't ask how I came to that, correct me if I am wrong) mechanical energy required would deplete 10-15% of the 2.4KW (what is a normal prop efficiency 70%+?) leaving me with 55% overall efficiency. Oh dear, I already see a shortfall. Help me out please.

[Guest]

start with the aerodynamic forces diagram at

http://paramotorclub.org/forum/viewtopic.php?t=833

you will see that a glider with a 5:1 lift to drag ratio will need a fifth of the all up weight as thrust for level flight.

So if your rig is 100kg all up you need 25 kg dynamic thrust to fly level. Any additional thrust and you will climb. The more thrust the better the climb rate. If you put a max climb rate limit to your design of say 1 m/s that will give you a trajectory angle you can apply to the force diagram and resolve the force (thrust) needed to climb your 100kg at 1m/s

There are standard formulae for deriving the prop pitch, diameter, rpm and required hp for a given thrust. A chain saw engine may be a little too weak. Although I think someone did use one as a winch where all the available hp goes into the thrust. (props are much less efficient)

[norman]

You enter the matrix of eternal dilemma. Max thrust is required at takeoff, that capacity isn't required in the cruise so the hardware you need for your launch is carried for the rest of the flight. Thing is, you only feel the weight when preparing for launch and after landing. JATO bottles are jettisonable but hey are still heavy. Maybe there is an ultralight version?

Francis has it maybe, assisted launch and low capacity sustainer able to support level flight or a modest climb to fly home when the lift dies. Perhaps wiggly amps are going to fill this gap with the electric paramotor?

Sounds like a lot of fun and just what the paraglider pilots need to get them into this sport.

[ArcusFlyer]

Interesting thread,

I am CP +15 hours hill flyer wanting to buy the best motor with lightness being my main criterion. The PAP TOP 80 and RAD arrow are on my shortlist. Are there any others I should be considering?

Chieftan is the TOP 80 noticably lighter than the other motors in your club or is it all much of a muchness. Has it been a good buy so far?

Thanks.

[Guest]

You might consider the epack http://paramotorclub.org/forum/viewtopic.php?t=1286 if you are prepared to wait a bit. What weight will it be Simon?

[Guest]

How long...

First Production units will be ready this summer

SW

[ArcusFlyer]

Yea, thanks guys.

Probably the wrong attitude (especially if I'm interested in lightness) going forwards but the thought of flying around strapped to a bunch of lipo batteries doesn't appeal as much as the smell of 2-stroke mix.

I started (and still am) in r/c helis and planes. I have electric (brushless / lipo) and i/c (smell of methanol, castor oil and nitromethane instead) of both and never really took to electric.

The easy thing about buying model engines is that, from my experience there's never been a rival to OS for build quality and reliability even when they used to be double the price of any other. In paramotors there isn't the same clear best of breed.

I've been looking into the custom air paramotor (lighter option) looks very nice and light. Might need to blow the budget.

[Jordan Berlin Potter]

On 30/03/2008 at 14:43, chieftan said:

There must be a few paramotoring manufacturers missing a trick. I fly a PAP Top 80 and would gladly lose my 400f/min full throttle climbs for an ultra-compact and super light unit that develops enough thrust for launch (I rarely use full throttle!) and for max 100f/min climbs. The idea being that the unit could be intergrated or developed around free flying and the better handling characteristics would allow higher profile, more efficient wings to be flown. I would love to try my Rebel on power but find my motor far to cumbersome to have any real attempt at thermalling. If it were developed to be suitable for more experienced flyers then the cage could be made out of plastic and other weight saving methods used as practicle. Less fuel too. Any suggestions.

Radne Raket 120 super light super quiet. I have 1 just for that reason. Its on a air conception light weight frame. Mine has been 120 hrs no motor outs. I've had to replace a few pull cords because they are very thin. The atom 80 is also a good 1 but weighs the same as the radne with less power. I think sound wise at idle the atom is a tad bit quieter, however full throttle they're about the same.