A Tale of Two Takeoffs

At a flyi that included various flying and landing contests, I was helping with the release of helium balloons for the pilots to try and pop. Harder than some would imagine, as there were a lot more misses than hits (except for ace pilots such as myself). Several of the missed balloons got sucked into the wing tip vortices where they almost stayed in place while rotating at least several hundred rpm. This experience, and other explanations of tip vortices, led me to believe they were of small diameter directly behind the aircraft and expanded in diameter the further back they got while sinking at several hundred feet per minute.

This picture is from "wiki".
https://upload.wikimedia.org/wikiped...ortex_edit.jpg

I was on a photoshoot for a backcountry flying video with my Husky at Nevada's Black Rock Desert. Near the north end of the desert there are a couple of small playas that are protected from the wind, surrounded by small mountains. The playa surface had fine alkali dust that readily showed the air disturbance behind the Husky, which normally takes off full flaps. As soon as the plane started its take off roll, each tip vortice looked to be about 20 feet in diameter, sucking the fine dust up from the ground and rolling it up and over onto the wing reaching almost to the fuselage - it looked impressive.

The Husky has a perhaps undeserved* reputation for "Moose Stalls". So named as the aircraft is typically circling low over game counting animal populations or doing photograph. It is thought the aircraft, while circling tightly, dirty or "slowed up" with flaps extended, flies into its own wake causing a low altitude stall and loss of control. I have flown into my own wake doing this, though at higher altitude with room to recover - it's an eye opener.

*Undeserved, not because it doesn't happen with the Husky, but rather that the Husky has been used by many state Fish and Games for animal surveys, predator control etc. - lots of exposure. There have been Super Cub crashes under similar circumstances.

http://cdn.shopify.com/s/files/1/011...f_jets.pdf?151
Page 2 "Wake turbulence"

At 07:40 19 June 2017, bumper wrote:
At a flyi that included various flying and landing contests, I was
helping
=
with the release of helium balloons for the pilots to try and pop. Harder
t=
han some would imagine, as there were a lot more misses than hits (except
f=
or ace pilots such as myself). Several of the missed balloons got sucked
in=
to the wing tip vortices where they almost stayed in place while rotating
a=
t least several hundred rpm. This experience, and other explanations of
tip=
vortices, led me to believe they were of small diameter directly behind
th=
e aircraft and expanded in diameter the further back they got while
sinking=
at several hundred feet per minute.

This picture is from "wiki".
https://upload.wikimedia.org/wikiped...lane_vortex_e=
dit.jpg/220px-Airplane_vortex_edit.jpg

I was on a photoshoot for a backcountry flying video with my Husky at
Nevad=
a's Black Rock Desert. Near the north end of the desert there are a
couple
=
of small playas that are protected from the wind, surrounded by small
mount=
ains. The playa surface had fine alkali dust that readily showed the air
di=
sturbance behind the Husky, which normally takes off full flaps. As soon
as=
the plane started its take off roll, each tip vortice looked to be about
2=
0 feet in diameter, sucking the fine dust up from the ground and rolling
it=
up and over onto the wing reaching almost to the fuselage - it looked
impr=
essive.

The Husky has a perhaps undeserved* reputation for "Moose Stalls". So
named=
as the aircraft is typically circling low over game counting animal
popula=
tions or doing photograph. It is thought the aircraft, while circling
tight=
ly, dirty or "slowed up" with flaps extended, flies into its own wake
causi=
ng a low altitude stall and loss of control. I have flown into my own
wake
=
doing this, though at higher altitude with room to recover - it's an eye
op=
ener.

*Undeserved, not because it doesn't happen with the Husky, but rather
that
=
the Husky has been used by many state Fish and Games for animal surveys,
pr=
edator control etc. - lots of exposure. There have been Super Cub crashes
u=
nder similar circumstances.

I feel like retitling this from TTTO (Tale of Two Takeoffs) to SSST (Survival Strategies for Slow Tows).

Does this mean that if we're trapped on a slow tow, we should drop down into low tow position...or move up even higher than normal (if that's possible by then)...or move out to the side--all to escape the downwash?

Chip Bearden
"JB"

On Monday, June 19, 2017 at 12:16:35 PM UTC-4, wrote:
I feel like retitling this from TTTO (Tale of Two Takeoffs) to SSST (Survival Strategies for Slow Tows).

Does this mean that if we're trapped on a slow tow, we should drop down into low tow position...or move up even higher than normal (if that's possible by then)...or move out to the side--all to escape the downwash?

Chip Bearden
"JB"

Speaking as a guy who's been the you ain't gonna have the choice. You are going to be heading for deep low tow whether you like it or not. Whether you fall off depends on what your tow pilot does next.

Evan Ludeman / T8

Responding to the slow tow matter...

I've written on this subject here on RAS before as it's one of my pet pive safety concerns. I've had a few seriously slow tows with water. My experience is that you will drop into low tow whether you want to or not - there's no choice to be had. In the extreme case, expect to be hanging lower than "low tow" at a high pitch angle slamming alierons to the stops. When this ocurrs at low altitude, there's no possibility of recovering should you disconnect from the rope.

I now keep printed instructions for towing with water ballast in the side compartment of my glider. If I don't have the chance to talk to the tow pilot immediately before the tow, then I will have the ground crew deliver written instructions to the tuggie as I'm being hooked up. Written instructions are less likely than a radio call to be confused, forgotten or misunderstood.

Here's a pdf of my written instruction sheet:
https://drive.google.com/file/d/0B_X...w?usp=drivesdk

Looks like Evan and I were typing at the same time and have had the same experience.

On Monday, June 19, 2017 at 2:25:49 PM UTC-4, Steve Koerner wrote:
Looks like Evan and I were typing at the same time and have had the same experience.

Yep. Loss of roll control in my case too.

-Evan

It's not like I haven't been there, guys. The ballasted occasions are almost all at contests and the tow pilots have generally responded to my agonized pleas for more speed.

The scariest one was actually dry, though, at a local club. It's the closest I've come to losing roll control or having to pull the release. And, yes, I was in near-low-tow position.

I was just wondering if settling even lower might help get me out of the downwash, at least when using a longish rope. I've towed at Hank's Middletown operation, which uses low tow exclusively, and if you're not used to it, it looks very strange (although it works very well). I don't think I've been down that low in my slow-tow adventures.

Chip Bearden
"JB"