Chapter 19 Situational Emergencies | Stretching Glide Story
Having the motor quit is no big deal if you’ve got a good landing option. Sometimes, though, even the best plans leave you needing to stretch your glide. The PPG bible covers this in nicely but here’s a summary.
Making it to the Beach or Road
When paralleling a long landing zone, like a shoreline, there are some special considerations.
When trying to glide to a straight shoreline where the entire length is landable, fly exactly perpendicular to the shoreline, accepting downwind drift.
Look at the diagram at right (click for full size). You’re cruising north at 20 mph in the face of a 10 mph headwind. The motor dies. Anywhere along the green area is safe landing territory. Which is your best option, A, B, or C?
If you answered anything other than B, read on.
When trying to make a fixed point over the ground it’s always best to make your ground track exactly towards the point. In the example, if you were going for a specific point, you would choose A, provided that was where you wanted to end up and indeed, your heading would be as illustrated–somewhat into the wind. But if you can land anywhere along that safe landing area, Choice B is best.
If you’re thinking that the most direct route, a tangent to shore, is best then you’re still thinking about a point. We have the entire shoreline to work with. Yes, you’ll travel over more water but ALL your progress will be towards shore instead of burning some fighting the wind.
Consider if the headwind were 20 mph. You would be standing still out there over the water all the way to splashdown. But if you head west, due west, now you are going 20 mph towards shore while drifting 20 mph to the left (south). Yes, you’ll land way down the shore but at least you’ll land, not splash (drown). Actually, in this situation, your glide ratio relative to the shore line is identical to having no wind whatsoever.
When faced with a long landing area like this, fly towards the area on a perpendicular heading, accepting the downwind drift.
Choice C is never best even though you build in a tailwind. The increased distance more than counters any benefit from a tailwind.
Tacking to go Upwind
A misconception we sometimes hear is the idea of “tacking” left and right to improve upwind penetration. That’s entirely false. A sailboat tacks into the wind by virtue of having water to push against. A paramotor has no such thing. It’s flying through the air in a block of air that we call wind. With no ground to push against, tacking has no benefit.
Think about this. You’re airspeed is 20 mph. The wind is out of the north at 19. If you head north you’re making 1 mph towards the destination. If you turn 30 degrees left of that you’re now only making 18.8 mph towards the destination AND DRIFTING LEFT of that straight line. Not good. This is akin to believing in a flat earth.
The Gist
Here is what to take away when Pushy stops pushing: 1) when trying to make a shoreline or other long landing area, head straight towards it and accept the downwind drift. 2) When trying to make a point, adjust heading so your ground track directly towards the point, and 3) when trying to penetrate upwind, follow rule 2, never “tacking.”