Mike,

Thanks for that story about Harris Hill. Did any of the gliders you
launched land back on top or did they land in the valley?

I used to go on ground launch safari with my partner in our LS-6a using
a 1,000' rope. Each flight would be straight out with the partner
bringing the trailer and we'd switch off each day. What a great time it
was.

Dan

On 9/30/2016 10:52 AM, Michael Opitz wrote:
At 15:43 30 September 2016, Dan Marotta wrote:
It did not look to me like a gravity launch would have worked at
the
airport in the commercial considering how close to the end of the
runway
the glider released the rope and how hard (apparently) the car
was
trying to pull. Still it was a heart-pounding video...
Dan,

It is a commercial designed to get your heart rate up. I don't know
about the location altitude/power degradation difference, but I have
participated in many auto tow launches from Harris Hill in past
years. The pavement is listed on the sectional at 1,100' long, plus
there is some grass going down the hill. The elevation difference
might be 50' by the time one gets down to the last usable grass.

During one 15 Meter Nationals back in the early 1980's, we had
scrubbed a day that was having a late afternoon frontal passage.
I announced that I would auto tow any competitors into the ridge lift
(after the front passed) if a launch was desired. A number of
competitors took me up on the offer, quite a few of whom did not
yet have ground launch endorsements. I gave them the requisite
instruction needed, and used my 1978 Chevy station wagon with a
small 283 cubic inch V8 (no anti-lock brakes yet either). Dick
Johnson rode "shotgun" next to me, and we used a standard ~250'
aerotow rope. We must have made at least 10 successful auto
launches into the ridge lift that afternoon alone, and every one of
those pilots that I launched came up to thank me for the experience
afterwards.

It would appear to me that the VW commercial overly dramatizes
how little room there was left for the car to stop. So, if that is the
case, then might not a gravity launch be possible given a good stiff
headwind? I don't know for sure about that, but I am pretty certain
that there was a much larger than apparent safety margin while
filming the commercial than there appears in the final product.

RO



--
Dan, 5J