Tow Plane Upsets......

I recently had a discussion with a CAP CFIG from Alaska that stated they actually tested the schewizer release on there tow plane at 45 degree angle up at 4000 pounds the release pressure on the handle was less than 25 lbs. Now I didn't get specifics as to method or condition of release. But it was his belief that it, as mentioned earlier in this thread, was more of a reaction time issue than ability. YRMV.

I have had the pleasure of taking tows behind Walt. He is best in show and a class act. I only have a few hundred tows in our club Pawnees and about 800tt in power and 50 in sailplanes so I'm no expert. What I do know is this: sailplane pilots are usually type-A and do a great job of rationalizing risk factors to themselves and others. Tost hook be damned, Walt- the variability in sailplane pilots at any club/commercial op will be a risk factor no modified release will solve for. It's a question of whether or not you are comfortable blocking out that idea or not. If I recall correctly, your past career is heavily analytical and clinical- I don't think this question is solvable that way.

The older, taller gliders were more problematic with CG hooks because the
hook was well below the actual CG. Some have a tendency to pitch up
excessively even on a winch.

I've taken aerotows on a CG hook in Pilatus, LS-4, ASW-20 and 27. None
harder than a nose hook in a Blanik.

The new designs are easier as long as the tow pilot gives you the
manufacturer recommended aerotow speed. One towpilot shorted me 10 kts
once too many times. I don't take tows from him any more as I got high
behind him twice and yanked.

The 27 with CG hook is lovely on aerotow, even through rotor. YMMV with
water and different CGs.

A nose hook is more work as you have to compensate for yaw and pitch
couples.

My question is which gliders with CG hooks are giving towpilots trouble?

Or is it a pilot problem?

Originally Posted by George Haeh

The older, taller gliders were more problematic with CG hooks because the
hook was well below the actual CG. Some have a tendency to pitch up
excessively even on a winch.

I've taken aerotows on a CG hook in Pilatus, LS-4, ASW-20 and 27. None
harder than a nose hook in a Blanik.

The new designs are easier as long as the tow pilot gives you the
manufacturer recommended aerotow speed. One towpilot shorted me 10 kts
once too many times. I don't take tows from him any more as I got high
behind him twice and yanked.

The 27 with CG hook is lovely on aerotow, even through rotor. YMMV with
water and different CGs.

A nose hook is more work as you have to compensate for yaw and pitch
couples.

My question is which gliders with CG hooks are giving towpilots trouble?

Or is it a pilot problem?

George, this was initially a pilot problem. A 15 year old student on her 3rd solo pattern tow and an older guy with obvious physical problems who had not taken an aero tow in a year or more are not the safest people to tow. That being said the next problem as previously stated is the Schweizer hook. It is well documented that under extreme pressure pulling the handle requires a herculean effort which I understand the a Tost conversion will correct. Then there is the question of the size and position of the release handle. It should be easily accessable and provide the necessary mechanical advantage. Someone mentioned reaction time. In one case I could see the belly of the glider in the mirror and I knew things were about to go bad but even if my hand was on the release at the time, by the time I knew I HAD to do it it would have been too late. It happened in the wink of an eye. The second time I could not see the glider as the student was out to the right and there is no mirror on the right side of the tow plane. There is ''NO ONE SIMPLE FIX."

Walt

On 4/25/2017 5:18 AM, Walt Connelly wrote:

snip
....

AND that the release handle
MUST be immediately available to the tow pilot, not down on the floor or
where one must bend and reach and feel for it and it must provide enough
mechanical advantage to accomplish the job.

/snip

It's been over a year but, IIRC, the release levers on the three tugs at
Sundance Aviation (Moriarty) are hinged at the floor with an
approximately 3-foot lever at about the same height as the throttle.
Easy to grab without looking and LOTS of mechanical advantage. Not
commenting at this time about the relative merits or each type of release.

Originally Posted by Dan Marotta

On 4/25/2017 5:18 AM, Walt Connelly wrote:

snip
....

AND that the release handle
MUST be immediately available to the tow pilot, not down on the floor or
where one must bend and reach and feel for it and it must provide enough
mechanical advantage to accomplish the job.

/snip

It's been over a year but, IIRC, the release levers on the three tugs at
Sundance Aviation (Moriarty) are hinged at the floor with an
approximately 3-foot lever at about the same height as the throttle.
Easy to grab without looking and LOTS of mechanical advantage. Not
commenting at this time about the relative merits or each type of release.

Dan,

Were these 3 foot handles the original design approved by the FAA or were they conversions later? I understand that it is not permissible to simply fabricate a longer handle and have it installed.

Walt

Walt, I can't answer that.

When I started towing at Sundance, both the CallAir and the Pawnee had
long handles. When the Ag Wagon came, it did, too. As I said, it's
been over a year since I looked into any of those cockpits, so I may not
be remembering correctly. I'll try to remember to take a look next time
I go to the airport.

Dan

On 4/27/2017 5:34 AM, Walt Connelly wrote:
Dan Marotta;944164 Wrote:
On 4/25/2017 5:18 AM, Walt Connelly wrote:

snip
....

AND that the release handle
MUST be immediately available to the tow pilot, not down on the floor or
where one must bend and reach and feel for it and it must provide enough
mechanical advantage to accomplish the job.

/snip

It's been over a year but, IIRC, the release levers on the three tugs at

Sundance Aviation (Moriarty) are hinged at the floor with an
approximately 3-foot lever at about the same height as the throttle.
Easy to grab without looking and LOTS of mechanical advantage. Not
commenting at this time about the relative merits or each type of
release.
Dan,

Were these 3 foot handles the original design approved by the FAA or
were they conversions later? I understand that it is not permissible to
simply fabricate a longer handle and have it installed.

Walt





--
Dan, 5J

Dan,

Were these 3 foot handles the original design approved by the FAA or
were they conversions later? I understand that it is not permissible to
simply fabricate a longer handle and have it installed.

Walt

It actually is relatively easy to approve a longer handle Walt. AC 43.13-2B You would need to do 337 and have an IA sign off on it.

Originally Posted by

I have had the pleasure of taking tows behind Walt. He is best in show and a class act. I only have a few hundred tows in our club Pawnees and about 800tt in power and 50 in sailplanes so I'm no expert. What I do know is this: sailplane pilots are usually type-A and do a great job of rationalizing risk factors to themselves and others. Tost hook be damned, Walt- the variability in sailplane pilots at any club/commercial op will be a risk factor no modified release will solve for. It's a question of whether or not you are comfortable blocking out that idea or not. If I recall correctly, your past career is heavily analytical and clinical- I don't think this question is solvable that way.

Rick,

I made a comment about the two pilots in question and you are right, there is a wide disparity among pilots relative to skill. A gentleman with obvious physical problems and a 15 year old student who never impressed me while she was dual are exactly the type you have to watch but if we only towed highly experienced pilots no one would get their license to gain that experience. That being said my analysis of the problem tells me that a Schweizer hook is inappropriate when we know the Tost will work under similar circumstances AND that the release handle MUST be immediately available to the tow pilot, not down on the floor or where one must bend and reach and feel for it and it must provide enough mechanical advantage to accomplish the job.

Learning that other clubs and facilities have changed to the Tost 30 years ago and that their handles are such that the pilot does not have to do Olympic class gymnastics to grab it concerns me. I realize that we can't pull things out of our asses today and rectify the problem immediately BUT I assure you things will be well underway today to correct my concerns OR I will be starting my second retirement a bit earlier than I had wanted to.

Walt