Tow question: Bad takeoff?

I was thinking the other day: What's going to happen to the tow plane if the glider behind me hits a wingtip on takeoff? He can't actually groundloop because, unless there's slack in the rope, he has to keep going straight forward. But if the tip digs in, could it be enough drag to pull the towplane around? Or is the rope going to snap first? Anyone ever had this happen to you?

Tina Marie

Hi Tina, Years ago I watched in disbelief as an experienced competition pilot drug his left wing which pulled him to the left side of a very wide runway (Minden). He didn't release and the resulting pull on the tow planes rear resulted in the tow being aimed to the right side of the runway. Still he didn't release and they finally got airborne heading across the runway. You tow pilots have more guts than I have, I would have toggled this guy off in a heartbeat. JJ

This is why we use weak links.

A long time ago I watched a glider drop its wing on take off behind a super cub. As the launch proceeded the glider wing stayed down and cause the glider to yaw towards the down wing. The tug proceeded and continued to accelerate. As the glider continued the yawing motion towards the down wing, it was enough to cause the swinging wing to lift. At this point the rope broke and the glider cart wheeled down the runway. I was one of the first to the glider and was amazed that in all the wreckage the pilot walked away. In the end the glider was a total write off. The tow pilot never new what happened, just that he felt a surge when the rope broke and he continued with the flight. Returning after a complete pattern and seeing the chaos on the ground.

Tina,

I hate to admit, but I am a sometimes 'regular' at banging a wingtip down on takeoff. The rubber skid gets scuffed a bit, I get things straightened out, and after that, things go 'normally.' These actions are on a paved runway and the towplane is a Varga Kachina with 180 h.p. Lycoming O-360. So far, I haven't had any tow pilots complain.

Gee, do I have to give my name after telling all I can't fly very well?

Ray Lovinggood, Carrboro, NC, USA

slides along the ground and does not dig in, but if it does; the glider does not, will not, continue going straight ahead. It will head for the side of the runway, and eventually either straighten out or break the rope. The diligent glider pilot will have released long before the rope has a chance to break. On a very slippery runway, I recently had an exciting but non-damaging ground loop while on tow.

>But if the tip digs in, could it be enough drag to pull the towplane around?

Not likely: The force on the tow plane is essentually straight back because of the length of the tow rope and the fact that the tow rope is fastened to the very rear of the tow plane way behind the center of gravity.

Yes, haven't broken a rope yet; I usually just release, sort things out and then try another launch. FAA regulations limit the strength of the tow rope to 200% of the sailplane weight in the hope that the rope will break before something (or someone) more expensive than the rope is damaged.

Fly Safe:

Yes. No. Yes. Don't think too much about why he's out there: He's out of control, and when he runs you out of elevator or rudder, so are you. Don't hesitate to pickle the rope at that instant. He might be able to get it together back there, but you don't know that and aren't obligated to bet your life on it.

Eric Plan ahead, stay alert, and never carry a package by the string.

I watched an experienced pilot attempting a take off behind a Pawnee after landing out in the middle of a horse racing track only 5km short of the airfield. I've often looked at this spot from the air and thought it would be OK to land. It looks a lot shorter from the ground when thinking about a take off.

Anyway, he was going quite well until his right wingtip clipped a tussock of grass. They were everywhere; Australian paddocks are typically very clumpy with the pasture grasses eaten down by stock leaving wiry tussocks of less palatable (I guess) stuff. He swung quite violently off to the right and then a combination of his compensating control input and the pull from the tug snapped him around the other way. He headed off to the left until the irresistible force of the tug snapped him around to the right again. He just couldn't seem to escape from the oscillation. He was just snapping around for the third time when he decided things were getting a little dangerous and he released. The tow plane looked remarkably unaffected by all this. Granted it was a brute of a Pawnee and the glider was a dry Libelle. The tug took off never to return and the glider was trailered home.

What glider do you fly, Ray? Some gliders are prone to this action, which can be cured (or at least mitigated) by various techniques, such as starting the tow with the spoilers open.