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Has anyone flown in the rain and light drizzle?


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Obviously you shouldn't fly in the rain, but sometimes you're in the air and it might start to drizzle and whatnot. 

According to a post on a paragliding forum, what happens in rain is that:

- The upper surface of the wing gets wet and becomes more draggy.

- The air isn't able to flow as quickly or smoothly over the upper surface of the wing, which increases the air pressure on the upper surface (Bernoulli's Principle).

- Because the air pressure increases on the upper surface, less lift is created. 

- On some wings, if the upper surface gets wet enough, the upper surface isn't able to generate enough lift and the wing goes into a parachutal stall, even at trim speed with hands up. 

- Since greater airspeed means more lift, the general advice is to put on speedbar and fly with trimmers out and hands up to try and counteract the drag on the upper surface. Try not to disturb the wing profile, and land as quickly and safely as possible. If a collapse occurs the stickiness of the water would mean re-inflation might not happen or will be delayed.

- Water can also get rammed into the cells and accumulate inside the trailing edge since there are no points of escape for water. 

1. Now, how this all translates into PPG flight is where I'm hazy; our wings generally fly faster, BUT at the same time they produce less lift and have worse glide ratios than freeflight wings, BUT thrust plus an increase in AoA increases the climb rate, so would it be fair to say that in rain, a PPG is safer because we have an artificial way of generating more lift? If we feel our wing going parachutal due to rain should we go hands up, put on speedbar, release the trimmers, and add a bit of throttle (not too much)?

2. How much rain is too much? The problem I see is placing quantitative values on all of this. For example, today the weather report said there would be 0.3mm rain / hour in one spot I wanted to fly in. This *feels* like it wouldn't be enough run to affect flight characteristics, because 0.3mm seems like a really tiny amount. At what level of rain would moisture dry almost instantly after hitting the fabric and getting blown dry by the wind? I would think though that *any* level of moisture would lead to more difficult re-inflations due to the fabric sticking together should a collapse occur.

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Yes most dangerus what you writen

"- Water can also get rammed into the cells and accumulate inside the trailing edge since there are no points of escape for water"

If water collect for longer period of time,

Then under heavy load water start pulling down trailing edge. breaking your wing until ritch stall point-then ?

Another dangerous think are ,if you get collapse wet wing, fabrick would like stick together like glue make impossible recovery.

Of course wet  fabric become more heavy prone to stall,and unpredictable behaviour

But to be honest if you feel raining then land immediately never trust any weather forecast some times instead of 0.3 you get 3mm or more

You have to know at last basics in predicting weather

I've been witness so many times when bad weather developed in matters of minutes

better give up- tomorrow will be day is well

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We DO NOT have an artificial way to generate lift. The motor generates thrust, which may be translated to lift by a correctly functioning wing.

The addition of thrust to a wing whose drag is increased will generate a greater angle of attack, bringing the wing closer to stalling. Any disturbance of airflow over the upper surface will also promote stalling, by causing the flow to detach from the surface.

We may have the advantage of greater wing loading and therefore greater flying speed.

I have been caught in drizzle once, free flying from tow. My lightly loaded wing felt like a brick and I landed quickly.

I would suggest that there is more value in learning to read the weather and avoid the issue altogether, rather than theorising as to how one might deal with it. Weather forecasting can be practiced every day whatever you are doing.

 

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Gary Smith and I once got caught in a 'light drizzle' whilst on a cross country (unforecasted)... I'd imagine a fair few others on here have too. It was not a full on code brown moment but obviously not the wisest either - due to all the reasons given above. I was flying an old ITV Boxer at the time (an active non-reflex wing) - the rain only lasted about 20 mins. In that instance I trimmed it right out, kept plenty of height and avoided any heavy brake inputs. The rain stopped before we came to land but, if it hadn't, I would have come in trimmed for a nice fast landing... just to be sure. Likewise, had it got much heavier I would have just landed asap.

The surprising thing is that its actually quite tricky to gauge exactly how heavy the rain is when flying along. i.e. you can't easily tell if its getting worse or not. Keeping an eye on how wet your knees are seemed to give the best indication of what was going on.

I won't ever plan to do it again but, if I did I'd also smear rainex on my mask!

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  • 3 weeks later...

Sasha dench I believe and Swans :-) 

flying when it's actually snowing is leathal. Your wing wil slowly fill with snow along the trailing edge starting at the tips. (I know this from it happening to me many moons ago) I was lucky and got it back down before it put me down!! I recon another few seconds and it would have been a different story all together. 

Flying with snow on the ground however is brilliant!!! :-) 

SW :D 

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19 hours ago, Animal said:

So no flying in the rain but what about snow I see somthing on TV and woman was going to follow some geese and it was in some frozen place with snow 

????

A few years ago i got caught out at base in heavy snow, paragliding over the black mountains until my decent rate alarm went off at 8 ms the wing was starting to stall and became unstable and the only way to keep it flying was a very steep nose down spiral of which isn't fun for to long all ended well but yes as simon said wait till the white stuff is on the ground first :) 

 

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I have been caught flying in light rain under power and unpowered a few times. I just try and fly away from the rain and apply speedbar/open up trimmers. Beware, although you might feel only a little wet, quite often the wing is getting much wetter (as it's acting like an umbrella to you).

 

I really do try to avoid flying in wet conditions. It's a horrible feeling thinking that your wing could just go parachutal and drop out the sky.  I have seen one person free flying get completely soaked within 10 mins of flying at St Andre when the conditions changed quickly. They spiralled down but them and the wing was utterly drenched. The wing never stopped flying though. I would be really concerned about line shrinkage due to wet lines in this sort of situation.

 

To answer your question - how much is too much? i have no idea. I certainly have no idea in mm/hr. All I know is that in my experience, with light rain the wing carries on flying ok - for how long this occurs though.... who knows.

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  • 2 weeks later...

Hi 

While all advise should be never fly in rain especially snow. How much rain can you get away with? 

A few years back i was doing the SSDR rally flying my old V5 and trusty   Ozone speedster, both myself and my flying buddy had a shower passing in front of us. We both held our course as it looked as tho it would pass in front of us,  unfortunately holding our course was to prove the wrong choice and we got wet, trying to go around and getting wetter and wetter,  By the time we passed the cloud and back into the sunshine we were both soaking wet,  Not wanting to slow our progress call it hard core, brave or god dam stupid we carried on flying... Full trims out never touching the brakes for fear of a full parachute stall.. Looking back we were both very lucky!!! 

Fast forward to the present, Flying a new wing i encountered a very minor patch of drizzle, No more than a few spots on the goggles, This time i was flying FULL SLOW as i had a low airtime pilot with me, who was flying on fast trims to keep up..  We passed the small patch of rain in about 1-2mins everything was dry my wing started to twitch pitch then violently roll... Stalling back then surging forward to the horizon ... My GPS showed 48kph forward speed down to 10kph as my wing was stalling out on me, 

One second i thought i had the glider under control then the next the circle of stall, pitching and yawing started all over again.. from 1000ft down to around 300-400ft i had thoughts of calling it a day and chucking my reserve but as soon as i went for the handle the glider seemed to be ok... again  stall pitch.. down to about 200ft i thought about pushing out the trims to accelerate the glider, BUT i didn't do this as i doubted my own judgement...   I 'landed' at 8M Per second... According to the wings designer this was my only option to regain control of the wing again....

Only Suffering from whiplash and bruising...I am lucky to be walking!!! 

All High end wings should not be flown when raining!! if you get caught out fly full fast trims NEVER touch the brakes just tips until your feet touch down... 

All the new crop of wings with there smoother surfaces will suffer from getting wet more so than the older wrinkly old gliders.. 

DO NOT fly in rain!! 

Fly safe 

 

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