On Sunday, February 16, 2014 5:01:24 AM UTC-6, Chris Rollings wrote:
At 10:06 16 February 2014, Jonathon May wrote:

At 08:50 16 February 2014, Chris Rollings wrote:

At 01:21 16 February 2014, Don Johnstone wrote:

At 22:39 11 February 2014, kirk.stant wrote:





Or, just teach the glider pilot to NEVER lose sight of the towplane,

and

to=

immediately release if he does. =20



Is it a matter of the FAA and insurance underwriters making any

change

to=

the status quo cost-prohibitive? What sort of gauntlet does one nee

to

r=

un?



One of the never to be breached rules of aerotowing for a glider pilot

i

the UK is "if at any time you loose sight of the tug for ANY reason yo

ar

to pull the release"

If you read Chris's article carefully you may deduce that in the wors

cas

scenario, the rapid vertical departure of the glider, by the time th

glider pilot realises he has lost sight of the tug, and attempts to pul

the release it is already far to late to make any significant differenc

t

what is going to happen.







"Our first conclusion was that, in the event of this sequence occurring

accidentally as a result of an inadvertent pitch up by the glider

pilot,

there was effectively no chance that either the glider pilot or

tow-pilot

would recognise the problem and pull the release in the available

time."



It was this very scenario that killed a very good friend of mine who

was



very experienced tug pilot. There are some events that, paradoxically

require corrective action to commence before onset if they are to b

effective in time to change the outcome.



As for cheap solutions, I am firmly of the view that most wooden glider

with only CoG hooks should not be aerotowed, those with compromise

hook

should be aerotowed with extreme care.







I would add that, although I haven't done the same tests with any glas

gliders, I'm pretty sure that many of the light-weight Standard/15m type

would behave in the same way on a C of G hook. Std Cirrus would be a

prim

candidate, would somebody with access to one care to try it at saf

altitude and report the result?



What I find rather sad about the gliding movement is the lack o

willingness to go and get the facts. We have been aware of this proble

for over 35 years, I described flights tests that I carried out, to try

t

improve understanding and seek a solution. Has anyone else done the

same?





In my opinion more relevant has any one tried these departures from track



with the next generation tugs eurofox to name but one.

We are all used to boxing the wake of a Pawnee and I know the teams

introducing them into clubs are taking a steady measured introduction .

But I don't want to be known as the the guy that killed the tuggie

because

I

didn't know what was acceptable .

My apologies to all at YGC for washing in public but this thread stirred

my



concerns and I know that when I get to fly behind the fox I will get a

briefing

But as Chris said until you have tested and published the results no one

knows.

Jon









Jon, I share your concern about the new generation of light-weight

tow-planes, I strongly suspect they will be more vulnerable to upset

accidents. I think that carrying out test like the ones I described should

be a requirement before the authorities approve the type for towing. It

may be possible I'll get the chance to try it out behind a Eurofox later

this year, I'll publish the results here if I do.

Imagine a proximity switch built into the tow hook in the nose of any glider. It could be adjusted in such a way that it senses the larger tow ring position moving down when the glider is kiting. That signal could be hooked up to a warning horn or speech output "Glider too high". I realize that the warning would sound on the ground until the rope is tight. Sensing airspeed above 25 knots would address that problem.
Herb