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Reflex wing and fuel consumption


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I bought my first PPG wing last month and have now flown about 6 hours on it. Before this one, I flew a DHV2 / ENC paragliding wing (a Freex Vaxin), and I usually found I used around 2.5l of fuel per hour (with a Rad Arrow). Since getting my Paramania Revo I have so far burned an average of 3.5l of fuel per hour. This is when flying trims in usually around the 'takeoff' setting on the trimmers.

I am enjoying flying the Revo because it is nice to be able to let the trimmers out and feel nice and stable in the rough stuff (my previous wing was very twitchy, unsurprisingly), but it seems a shame to have to fly everywhere on full throttle and to use so much more fuel. But perhaps that's the price you pay for a bit more speed and stability.

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Normal to get this. Trade off all the while. I still fly the the engine I flew in the 90's and could never maintain level flight on full trims on a mid 2000's Reflex wing. But the wing felt very stable on full chat. The modern ppg wings are better, but so are the modern PG wings.

Richard

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Revo 1 is a bot old now, my Nuc is not considered cutting edge either but I still only have to fly with half throttle on full trim, not screaming the motor in any way,did you mean to say with the trimmers in take off position you are having to give it lots of throttle for level flight?

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Yes, that's exactly right, I have to fly on full throttle all the time to maintain level flight with the trims on the Neutral setting. And if there's sinky air about (as there was last night) sometimes I can't maintain level flight even on full throttle!

Last week I flew at midday in some pretty boisterous air and flew mostly on full trims-out and it did feel nice and stable and I didn't use much fuel but that's because I used the thermals carefully (I have been freeflying for around 8 years so have a fair bit of XC experience) but that's not really what I went into PPG for.

I guess that a lot of this is down to my motor which is an old Rad Arrow. So perhaps I would be better off trading in my extra speed and reverting back to a PG wing (a DHV1 or 1-2 to retain some of the passive safety).

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Sadly more power is not an option for the moment - my next motor needs at least another 2 years of saving up!

So perhaps reverting back to a PG wing is the best option with my current motor. Although I can fly faster with the Revo, I don't like flying at full throttle all the time - I'd rather fly a bit slower and use 1/2 to 3/4 throttle.

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A paramotor (say) AUW of 150kg and at (say) 50kg of thrust at full revs, will struggle with the older PPG wings. Full fast trims and full speed bar (with an upright pilot and a big fan/cage) will probably have an L/D glide ratio worse than 3:1 (Drag of 50kg) and therefore not keep level flight in this mode. (simplistic aero theory, but a good approximation for our relatively slow flying aircraft).

Richard

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Turn,

I don't know your motor at all but does it seen to have a bit of extra power? Does it spin up the prop fast? or maybe not and its getting tired?

What I'm thinking is a bigger prop if the motor and gear set can handle it. I run a mini top80 and a 130prop with lots of power.

But maybe the guys are right older wing and older motor could be a combo effect of the two.

Maybe if your mechanically inclined you can hone the cylinder pick up some rings and breath a little life back into the old girl (low cost). In my experience 2 strokes come back to life with a new set of reeds and rings.

cheers

T

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I think the motor is fine (as it flew well with my DHV2 paragliding wing), but perhaps it is simply not well-matched to a first-generation reflex wing like the Revolution. They weren't around when my motor was built, so it is mis-matched technology.

When I have saved up a little money I will take the motor to a 2-stroke expert and see what they can do with it. There isn't enough cage clearance to fit a bigger prop.

A friend of mine has offered me to try a Gradient Golden, so I'll give it a go and compare the two.

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My guess is its an old rad arrow Dave !! :wink:

was it your old motor Clive, the one you said you sold as it was shagged and on its way out, needed a rebore or something, you said you were goner find some mug to by it before it went bang. is it that one Clive :?::lol:

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Tom, on that Golden 2 I think you need to change the risers not sure. But I've heard they are ok for PPG just a bit slow unless you get on the speedbar. But as you know the Golden 2 speed bar is not something to be played with they are famous for frontal's on full speed bar.

How many cc's is that motor? I have the miniplane 80cc small frame and the large 130prop. The cage does not really cover the prop but it's what ever your comfortable with. I have a 26m Ozone Speedster and issue pushing the glider with 80cc.

Yea might be worth looking thought the books and see if you can find the compression values for that motor then pick up a cheap compression tester $15-20. This will end the motor debate really quick.

It will also prove if this motor is Clive's old unit lol.

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Tom, on that Golden 2 I think you need to change the risers not sure. But I've heard they are ok for PPG just a bit slow unless you get on the speedbar. But as you know the Golden 2 speed bar is not something to be played with they are famous for frontal's on full speed bar.

How many cc's is that motor? I have the miniplane 80cc small frame and the large 130prop. The cage does not really cover the prop but it's what ever your comfortable with. I have a 26m Ozone Speedster and issue pushing the glider with 80cc.

Yea might be worth looking thought the books and see if you can find the compression values for that motor then pick up a cheap compression tester $15-20. This will end the motor debate really quick.

It will also prove if this motor is Clive's old unit lol.

I was joking when I wrote that :D:D:D

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My cruise speed on a modern ENC PG wing is 40kph at 2,700 revs and I average 3.75l/hour.

My top speed on full bar is 54kph at 3,200 revs and I average 6.25 l/hour.

(Top engine revs is 3800).

A cubed increase in consumption relative to revs. This is significant when you consider some of the older more inefficient PPG wings.

Richard

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Even with the most effecient wing, the power required to travel faster is proportional to the square of your speed, so to double your speed you need four times the power.

In addition to this is the characteristic of your prop and engine:

Thrust from the prop (at a given RPM) will decrease with forward speed.

As forward speed increases, the prop and engine must increase RPM to maintain thrust. As RPM increases, the drag of the prop blades themselves also increases as a square law.

If your prop pitch and gearing are set up for peak power at, say 30k forward speed, any greater speed will allow the engine to spin faster than it's peak power RPM and its effeciency will decrease.

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Tom, on that Golden 2 I think you need to change the risers not sure. But I've heard they are ok for PPG just a bit slow unless you get on the speedbar. But as you know the Golden 2 speed bar is not something to be played with they are famous for frontal's on full speed bar.

How many cc's is that motor? I have the miniplane 80cc small frame and the large 130prop. The cage does not really cover the prop but it's what ever your comfortable with. I have a 26m Ozone Speedster and issue pushing the glider with 80cc.

Yea might be worth looking thought the books and see if you can find the compression values for that motor then pick up a cheap compression tester $15-20. This will end the motor debate really quick.

It will also prove if this motor is Clive's old unit lol.

I was joking when I wrote that :D:D:D

lol I know I was just giving him another poke!

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Tom, on that Golden 2 I think you need to change the risers not sure. But I've heard they are ok for PPG just a bit slow unless you get on the speedbar. But as you know the Golden 2 speed bar is not something to be played with they are famous for frontal's on full speed bar.

How many cc's is that motor? I have the miniplane 80cc small frame and the large 130prop. The cage does not really cover the prop but it's what ever your comfortable with. I have a 26m Ozone Speedster and issue pushing the glider with 80cc.

Yea might be worth looking thought the books and see if you can find the compression values for that motor then pick up a cheap compression tester $15-20. This will end the motor debate really quick.

It will also prove if this motor is Clive's old unit lol.

I was joking when I wrote that :D:D:D

lol I know I was just giving him another poke!

:lol::lol:

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Yep, that was me over Misterton. 600ft on the way out, and a gradual climb up to 1500ft over Beaminster. I returned at 1300ft above Misterton on my way back home. Where are you based? Misterton I'm guessing :D If you're that close by, it would be great to get together for a fly.

Flew for 50 minutes last night with the trims mostly on the slowest setting. My max engine revs is 9600rpm, and I was cruising level at about 8700rpm. I used 3.5l in 50 minutes. So next time it looks nice a evening for flying, I'll go out on the Golden2 and see what the difference is...

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