Getting caught in the rain while paramotoring has a rightfully bad rap. It increases your chance of entering parachutal stall and may worsen the paraglider’s ability to recover from a collapse. Ehats worse is that, when combined with airflow degradation on the wing’s surfaces, rain accumulation in the cells can cause spontaneous entry into parachutal stall.
Just getting a wing wet makes you a test pilot because no certification program tests this condition. In a wing fold it’s likely the fabric will stick together to some degree, slowing recovery. It may not be much, it may only only add a half second, but that could be enough time to worsen a resulting bank and let Earth intervene before control is regained. Or the wet fabric may not recover at all.
Disruption of airflow on the surfaces may not seem like much of an effect, given that airplanes fly just fine in the rain, but our speeds are so slow that the effect may be worse.
Having a wing model with holes in the trailing edge may help, but water still accumulates in places the holes don’t drain. Plus, surface disruption still happens.
What To Do if you get Caught In Rain
As mentioned, rain accumulating in the aft portion of cells may cause spontaneous entery into parachutal stall. Even if it doesn’t happen, parachutal stall is more likely. These steps will help:
1. Land immediately. How quickly you land depends on how good the landing options are and how hard it’s raining. With good landing options there’s little reason to continue. If it starts raining real hard, accept a less ideal landing site.
2. If your wing maker has guidance on this situation, follow it.
3. Set trimmers to fast, or apply speedbar while steering with the tips or stabilos (not main brakes).
4. Avoid Big Ears. The extra drag of folded fabric can provoke parachutal stall.
5. Consider using a steep turn (NOT a nose-over spiral) to stay loaded during descent. That lessens the chance for parachutal stall while getting out of the situation quicker.
6. Minimize brake use. Consider flaring with partial power instead of brakes. Use brakes only in the last few feet as necessary.
7. If it’s turbulent, balance brake use to keep the wing open with minimum pull.
Video of Parachutal Stall After Flying in the Rain
This video shows an example of spontaneous parachutal stall due to rain.