Reflexs wings vs Normal wings

[thijs]

Hello people,

In Holland we have a big discussion about reflex wings. I think it's not only in Holland but also in the rest of europe.

Some people claim the reflex wings are dangerous, because of their reactions. Collapses for example.

I flew the Action Gt and the Synthesis and soon I have a new reflex wing for myself, but I can't find any bad behaviour stories about it ( if you fly normal ).

I searched for some accidents due to the wing an not made by the pilot, but I can't find anything.

So it's strangle some people say the reflex wings are very dangerous, but I can't find any bad data about it.

How are the opions in England. I see there are lots of good comments about the reflex wings. Maybe can share some good or bad stories? Is there a estimated percentage of the ppg pilots flying with reflex paragliders?

Greets from the other side of the canal,

Thijs

[weesplat]

Hi Thijs,

I think the things said about reflex wings depends on how the things looked at.

Hard to collapse and very stable makes it good.

Once collapsed very dynamic and longer to recover makes it bad.

I personally go with the first point of view.

I would say that about 70 to 80 % of the club members fly reflex type wings.

I certainly havent heard of incidents or situations due to the wing rather than the pilot.

Whats the flying like in your part of the world. Would have thought that there would be very little free flying due to the lack of hills. Perfect for paramotoring though.

Hey why not talk to simon and be our first international branch.

cheers Col....

[togsie]

Dag Thijs,

Whereabouts in Holland do you do your flying?

Regards.

Togsie

[Guest]

Non refelx wings have been around for ages and all the problems and behaviours have been examined and statistics gathered. There is too litle data on reflex wings to really form sensible conclusions about their recovery from dynamic situations. Normal wings are recently subject to examination and the DHV testing has been changed to reflect new understanding of the angle of fold during a collapse. The test pilots now have to induce a collapse of a particular type during the test in order to categorise the glider.

see http://www.dhv.de/typo/index.php?id=715 ... _news=1835

Reflex wings (Dudek and Paramania really the only ones in popular use) do not follow the DHV homolgation route so we do not know how they behave from following deep asymetric except a few anecdotal (you-tube) stories. Also add to the equation a motor force, gyroscopic precession of the prop and inertia of the pilot and motor and the deep asymetric collapse can become a very interesting experience.

At the moment we simply dont know whether reflex wings in general, or which ones in particular may be "demanding" of the pilot in recovery. BUT similarly we dont know (there is no homolgation programme) how NON rfelx wings compare with rfelex wings when under power.

All we have is a few stories of what happened to this or that pilot, without really the full details of the conditions or pilot input.

We do know that the wash-in at the tips has been reduced to increase speed and the reflex section is relied on for pitch stability instead. BUT reflex wings can be set to reduce or eliminate the reflex profile for slower speeds. My concern is for these wings when flying in this configuration.

Having said that, if flown as recommended (no speed bar when in non-reflex) I do not hear of any major problems.

In conclusion I personally say that reflex wings do not appear to be inherently more difficult or dangerous to fly when flown within the limits of the careful pilot and the manufacturers brief. But individual reflex wings (and individual non reflex wings) can have idiosyncrasies that make them "interesting" in dynamic deep asymetric under power. (they fold vertically down and the drag whips them round 180 in no time as the pilot continues forwards and upwards so you end up flying backwards diving at the ground- not good ).

[Mike]

Hi Francis,

In addition to your post, my first couple of flights with a motor, l was flying a PG wing and on strait and level flight l had a full symetric. It lasted about three seconds and with a dab of break came strait out again. But since buying a Synthesis PPG wing the diffrence is amazing l havn't been in any bad turbulance with the wing yet but the stability and reassuring feel of the wing is great. The take off also with a reflex wing is so much more stable and when high enough to take of trims, the attitude of the wing knuckles down to forward motion and with the speed bar on you are really flying fast over the ground.

Mike

[thijs]

Hi all,

Holland is a very very flat country. We have dunes at the beach and it's even possible to make free flight trips of 30 km to the other side and 30 km back. All the ather free flight are done by winching.

There are about 100 registrated paramotor pilots in Holland. Maybe 6 people ( 6% ) flies reflex wings.

The rest flies standard glider like powerplay and other DHV 1-2 gliders.

We always got windy conditions. I think it's 100% the same as in England, because we always get the weather blown from England. In the summertime we have times of beautiful weather. Then it's perfect to fly around Holland.

It's not so populair as in other countries because not only we need to pay for the equipement, we also need to register our paramotor at the authorities. This cost around 500,- euro. After registering it costs around the 100,- euro each year. To get a legal airstrip for take off it cost 500,- each year. So it's very expensive to start paramotoring. But still it's the cheapest way to fly motorised.

The bad thing of Holland is our tiny country. The international and military airports are close to eachother, same like in Belgium. So for long distance trips we always need to look out for the Control zones. We are also limited to a height of 1500 ft or 450 mtr. Luckely our slow flying speeds make our country look big .

greets Thijs

[Guest]

Very interesting post there, Francis. With regard to the Synthesis, does that have any reflex when the trims are at zero or fully pulled in for slow flight? If there is none, presumably we should be flying actively when the wing is in those trim configurations, would you agree? Personally I only ever slow down for take off and landing

[pete_b]

Hi Thijs

I have flown both non reflex (Eagle Genie 80 hours approx) and reflex (Reaction 120 hours approx)

The Genie was a good wing that needed hands on flying (just in case) had some collapses and did siv goes in to collapses and comes out with no great worries ( except when you spin it and tumble 3000 feet, but thats another story)

Reaction I always fly hands off except for take off and landing.

I have flown in VERY turbulent conditions (my fault)with wing tips folding but just let the reflex do its job when it got really rough I went to full speed bar and that seamed to make it more stable.

I will allways fly under power with the trims out and hands off.

Pete b

but then thats just me.

[Guest]

Hi v23nb, I recommend flying actively at all times (I am a paraglider primarily so come at flying always expecting collapses and seeking turbulence ie thermals). Of course paramotoring is usually done at the least turbulent times, but landing and taking off is done in the most turbulent layer of air, the bit next to the ground where it is being heated and cooled and made to go round stuff so active flying during take off and landing is a GOOD THING whatever wing you are on.

I do not know if there is any reflex in a synthesis with the trims full on. we would need Clive to get that from Dudek. I also dont know how much wash-in the synthesis has at the wing tips (more than the Action GT or Reaction I would guess as its a bit slower). These are the things that the designer tweaks to get best performance from the design brief and they are therefore reluctant to give the figures I guess.

the main point I was making is that the jury is still out re relative safety of the principle of this wing design because there is not yet (God forbid) enought data to derive meaningful statistics.

I understand that Dudek reccommend taking off and landing with some trim pulled on (I think there is a mark on the trim tab?). My assumption is that at that setting there is still some reflex in the wing to maintain pitch stabilitybut we would need confirmation from simon or Clive.

My own flying philosophy is that planets are hard and getting as far from them as possible is "safety". also the boundary layer of air is where most of the turbulence is. So take off at the safest configuration (some reflex) and get above 500 feet as quickly and safely as possible. Height gives you opportunity to recover and , as peteb posts without much drama.

On the other hand take a look at Tony Gibson with trims full on and full speed bar (not recommended) and full power on an Action GT

I would want at least twice the height he had if I ever had that happen.....

Edited December 4, 2007 by Guest

[Guest]

Francis, you say you fly actively at all times. Surely not when you have the trimmers let out? Any brake applied then is surely just reducing the amount of reflex and therefore reducing some of the benefits of having the reflex in the first place.

Clive - could you give us an answer please with regard to the Synthesis and the Reaction. Is there any part of the trim range where the profile does not have any reflex. Obviously there is not a straight on/off answer here (the level of increased resistance will be progressive with the amount of trim applied) but it would help give us an idea.

[Guest]

Sorry didnt make it that clear, I fly an Independence avalon with no trimmers and no reflex. I use the motor to get aloft and turn it off to thermal, so I fly on active (turbulent) days. But of course you are right, I do not fly "actively" every moment of the flight.

The whole concept of reflex flying is new to me. I am trying to get an understanding of what would make good techniques and see what applies from flying non reflex and what is counterproductive. You are right that when using the reflex you would permit that to maintain your pitch stability so you would not use the controls but as you point out the reflex is progressive, not on-off so I am trying to establish where the concept of "active flying" takes over to maintain pitch stability.

[Guest]

Thanks again for the reply. If you get an answer to this please let us know. Out of interest I only ever use 2 settings on my trimmers, the zero position for take off and landing and full fast when I'm up and away, trying to go places. I never use full slow as never feel I need it.

[Guest]

Thanks again for the reply. If you get an answer to this please let us know. Out of interest I only ever use 2 settings on my trimmers, the zero position for take off and landing and full fast when I'm up and away, trying to go places. I never use full slow as never feel I need it.

Same for me.

SW

[Guest]

Your use of the trims agrees with my own experience of tandem wings. On tandems there is usually a trimmer system (but not to the point of reflex). I see these as ON or OFF not a progressive speed system. So you get two speed ranges or two "gears". It seems that the Reflex wing trim tabs work similarly and many pilots use the trims at zero to get best sink rate ( and slow landing/take-off speeds) and trims OFF to get max speed straight and level (and presumably best fuel economy? - less drag?) using power-on to climb and power down to sink out?.

I understand that there is some reflex at this trim setting but would like that confirmed by Dudek and Paramania. What I am still unclear about is the purpose of the trims FULLY ON setting. What I would hope for is that it induces some wash in at the tips which would make the glider more stable at this setting by kepping asymetrics from progressing across the wing..... but the fact that you are advised not to reduce the angle of attack (use speed bar) when set to fully ON makes me doubt that.

[dantheman]

The Paramania manual is pretty clear about the use of the trimmers, basically full trim put's you in "paraglider" mode with maximum lift and that is also the setting you would use to free fly.

Taken from the Paramania manual:

3.1 Flying With and Without a Motor

Although the design philosophy of the Revolution is that of a high-speed paramotor wing, which performs well as a free flying glider and may be flown as such with no adjustment. Slower trim settings, reduce internal air pressure and consequently give a lighter feel to the brakes and a better sink rate..

On faster trim or speed bar settings, brake pressures generally increase and weight-shift or a wing tip stabiliser becomes more effective. On the slower settings, sink rate improves and handling becomes lighter enabling you to make best use of thermal cores whilst giving you an improved climb rate and shorter slower take-offs and landings.

3.3.a Power-off Landings

If you aim at a precision or tight landing, or in nil-wind conditions, it is advisable to use half or even full trim (maximum lift configuration).

This will hardly alter your glide angle but will decreases your sink rate; these decisions become more critical at higher wing loadings.

[Guest]

Thanks Dan, interesting stuff. Do Dudek designs work the same way though. Clive?

[Guest]

Thanks Dan.

What does the manual say about use of speed bar when in full trim mode? And does the Action GT have different advice do you know?

[dantheman]

The Action GT manual is on the www.flyparamania.com website,

http://flyparamania.com/downloads/actionGTmanual.pdf

With this warning:

The Revolution manual says the following re speed bar:

Use of the speed bar

The bar increases the speed by approximately 30%. Unlike most wings there is little or no loss of stability, in fact the wing seems to cut through turbulence even better than before application. However, if any instability is encountered due to excessive conditions it is recommended to release the bar for recovery and to return to normal flying mode. The brake pressures also increase when the bar is used, so it is more for use during straight and level flight.

As you become more experienced, careful release of the bar whilst entering turns gives an effect, similar to pulling the stick back in a conventional aircraft.

Although the speed bar can be used with confidence throughout the whole range of the trim settings, it is obviously most effective when used with the trims off I.e. on the fast setting.