Which way do you roll?

SixPapaCharlie

SixPapaCharlie

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You're in a light single following another light single you get caught in his propwash, or wake or whatever you want to call it.

Which way do you expect your aircraft to roll and why?


Edit: it's not a Yak
 
you've seen videos of what the wingtip vortices do. I would 'think' it would depend on how you entered that mess. watch a video on it then pick different points as entry points and go from there. I will not, however, be doing any practical tests to determine the actual answer.
 
SixPapaCharlie said:
You're in a light single following another light single you get caught in his propwash, or wake or whatever you want to call it.

Which way do you expect your aircraft to roll and why?


Edit: it's not a Yak
Click to expand...
Depends whether you hit the wingtip vortices from the left or right wing.
 
Propwash, wake, and vortices all do different things, but a couple hundred feet behind a light single it just mixes up the air into a turbulent mess. A standard glider practice maneuver is to descend through the tow plane's wake, and it just gets bumpy. No particular rolling motion.
 
I have gone both ways in the past. Just depends on the scenario. Every time no one got hurt, it was a little scary but actually kinda fun.
 
Never experienced prop wash from a light single.
 
As previous mentioned the Wake from a light aircraft is pretty much just going to be turbulence. Only way you will experience Prop wash is if you are behind the airplane while it is on the ground but not flying yet. Prop Wash can pretty significantly cause the right wing of the glider to drop when you hit it.

Brian
 
Whilst flying 70kts at 1800 ft down the tracks to Fisk, twice I found my plane making a significant and uncontrolled rolling motion to the left.
It was enough that I cranked the yoke to the right and got no response then checked to make sure the A/P was off. Lets call the whole event 4 seconds in duration.

Happened twice and something I hadn't experienced before. I assumed once I confirmed aileron deflection was working that I was caught in a tractor beam from the aircraft in front of me.
I had thought this rolling would have come from the prop which would have made more sense if it rolled me to my right.
 
SixPapaCharlie said:
Whilst flying 70kts at 1800 ft down the tracks to Fisk, twice I found my plane making a significant and uncontrolled rolling motion to the left.
It was enough that I cranked the yoke to the right and got no response then checked to make sure the A/P was off. Lets call the whole event 4 seconds in duration.

Happened twice and something I hadn't experienced before. I assumed once I confirmed aileron deflection was working that I was caught in a tractor beam from the aircraft in front of me.
I had thought this rolling would have come from the prop which would have made more sense if it rolled me to my right.
Click to expand...
If you watch Jason Schappert’s video of his flight into Oshkosh this year, he had the same experience and attributed it to wake turbulence.
 
I got it flying formation with a Harmon Rocket once. Same feeling, check that the autopilot is disengaged due to the stiff controls.
 
If you hit a strong thermal with one wing, you'd get the same sensation.
 
Rolled left and right on both glider tow and what little EAB formation stuff I’ve done. Same thing with helos. Flying through dust devils, well it’s just one big thump. :)
 
In a similar vein, one of my passengers remarked while cleaning bugs that the underside of the right wing and topside of the left wing had more bug guts than the topside of the right and underside of the left.
 
I would say most likely to the left. If you are off to the left of the wash, and your right wing drifts into it, it would tend to push your right wing up, rolling you to the left. Likewise, if were off to the right and drifted into the wash with your left wing it would tend to push your left wing down, rolling you to the left. I suppose if you hit the wash straight on, it might roll you to the right.

I've encountered this a few times when following closely behind another plane. The first time was 10 years ago on my first trip to Oshkosh. We had a flight of 7 with about 1/2 mile spacing, and I was rolled about 45 degrees, but I forget if it was left or right. It's happened a few time in the years since then when following closely behind someone, and I really don't remember which way I rolled. Next time, I'll pay attention, but my money is on rolling left.
 
pburger said:
I would say most likely to the left. If you are off to the left of the wash, and your right wing drifts into it, it would tend to push your right wing up, rolling you to the left. Likewise, if were off to the right and drifted into the wash with your left wing it would tend to push your left wing down, rolling you to the left. I suppose if you hit the wash straight on, it might roll you to the right.

I've encountered this a few times when following closely behind another plane. The first time was 10 years ago on my first trip to Oshkosh. We had a flight of 7 with about 1/2 mile spacing, and I was rolled about 45 degrees, but I forget if it was left or right. It's happened a few time in the years since then when following closely behind someone, and I really don't remember which way I rolled. Next time, I'll pay attention, but my money is on rolling left.
Click to expand...

Here's the plane you're following. Where are you? Between it's vortices? Left? Right? Which one of your wingtips encounters which vortice, from which side?

vortex.jpg
 
SixPapaCharlie said:
You're in a light single following another light single you get caught in his propwash, or wake or whatever you want to call it.

Which way do you expect your aircraft to roll and why?


Edit: it's not a Yak
Click to expand...
I wouldn't worry about it too much. Having trained at a Bravo, we were more concerned with heavies.
 
In a light plane, ground maneuvers, or close to the ground, such as during take off, or around larger aircraft, or roto wings, is when you can very quickly get into serious trouble. Also, when you're behind another aircraft on the ground, be prepared for the idiots who will sometimes, for no reason, blast you with their propwash.

Whether on the ground, or in the air in a light plane, always try to visualize where the other guys disturbed air is likely to be. If you're on the ground, try to stay well behind, or on the upwind side. Airborne, generally, when following, stay well behind, off to the side, or above.

When airborne, the turbulence produced by a small fixed wing generally will produce a bumpy ride, or can produce a short duration of uncontrolled movement in any direction. It can get your attention, but is normally not a big deal if you're prepared, and make the necessary control corrections.

Heavies, caution..... In a light plane, never, ever, get too close to the tail end of a heavy, on the ground, or in the air. Depending on how big the aircraft is, the serious turbulence left by a large aircraft can be found several thousand feet behind, normally below, and depending on winds, can be far downwind from it's flight track. Basically, visualize where the turbulence is likely to be, and be alert.
 
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