Nigel, I read your post and it's mostly an "old wives tale".

Yes, gliders lower their tails which can be an issue on hard surfaces so someone holds them down as seen in the PW-5 video. On turf, it's a non-issue.. However, it has nothing to do with acceleration causing premature uncommanded rotation. The tailwheel on the ground prevents it. Glider's don't "shoot into the air" or do anything else inappropriate under 1G acceleration. It's been thoroughly flight tested.

On Monday, July 1, 2013 8:58:00 AM UTC-6, Nigel Pocock wrote:
If Bill D could be bothered to read my posting before spouting a reply he

wouls see that I had started the launch with full forward stick in both

cases.

Hard acceration with these gliders can cause the tail to hit the ground

hard - not safe. To avoid this the tail of the K8s are usually held down

for the launch. Too hard acceration can cause the glider to shoot into the

air and immediately into a 45 degree climb despite the stick position. If

the rope breaks at this point you have too little height to recover. Hence

the winch driver will give slower initial acceleration with these types.

By regained control I mean the elevator having any effect. Until then you

are just a passenger.

I was always taught with ground launch to keep it straight and level until

the glider lifts off in a shallow climb. When a safe speed had been reached

to rotate steadily into a full climb. At any point in this process you can

still recover and land safely using the correct procedures - as taught be

both the german and british systems.





At 14:42 29 June 2013, Bill D wrote:

On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:

Excessive initial ecceleration can cause problems with certain types. I

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have experienced it with 2 types.=20

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PW5 with stick fully forward at the start of the launch. Hard

acceleratio=

n

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caused the glider to rotate from the nose wheel to the tail wheel and

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rocket into the air. I only managed to regain control at about 50ft.

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The other one is the K8. Light glider, high wing. Similar problem.

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If slow acceleration is a safety problem what about the ground run and

ta=

ke

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off with aerotow using belly hooks, and autotows?



K8's and PW-5's, as with all "nose dragger's, are supposed to rotate back

o=

nto their tail wheels. What do you mean exactly by "regained control"?

Yo=

u're still with us so, presumably, it worked. With those gliders you

shoul=

d have started the ground roll with the stick full forward.



Aero tow with a CG hook isn't safe as discussed elsewhere on this forum.

H=

owever a tug can't generate the forces a winch can so a wing drop induced

g=

round loop likely won't be as severe.