Launching trollies.

There is such a range, depending on the type of AC, that it is hard to give a good answer. 10 MPH for sme floaters, to 50 MPH and above for some warbirds and racers.

For most cases, I don't see a big advantage. The AC has plenty of power to take-off from a trolley, if it has enough power to perform "with sprit".

I can see an advantage if the runway is bumpy, or has long grass.

If you were using a yard for a runway, the grass is usually way too long to make easy take-offs, so the extra power from a car would probably help.

One neat advantage to a powered trolley (especially on a busy runway) would be the fact that you would not have to go out onto the runway to retrieve the trolley.

If you got really bored, you could try to land on the trolley! That would be a trick! :-)

On Sun, 18 Mar 2007 01:10:22 GMT, Terence Lynock wrote in :

I think that depends a GREAT deal on the wing loading, drag coefficient, airfoil, and the angle of incidence as the aircraft gains speed.

I think those are the wrong questions.

Do you have a friend ready to drive the car for you?

Would you have fun trying it?

Let us know how it turns out!

My buddy, Dan, and I played with a glider last year, a GP Spirit towed by a .60-size trainer. The first few flights, we had a third person toss the glider as the trainer wound up. The third person eventually said, "Just tow it off the grass." We did that for the rest of the summer with only one take-off crash.

Marty

The message from "Morgans" contains these words:

Hi Jim, saw an old newsreel of a bipe touching down on the back of a truck then lifting off again and wondered what would happen if things went wrong, one good thing about a powered trolley would be you can fit it with suspension and take a lot of the bumps and thumps away from the aircraft and once the a/c is up and away you could drive the trolley back for the next one,

regards, Terry

from "Martin X. Moleski, SJ" contains these words:

Hi Martin,

This is the problem when you are on your own really as other members want to get on with flying their own a/c, although there is always plenty of help within a club you dont want to be a constant pain in the butt, it is quite possible to mod the steering so the launch trolley travels in a straight line and only needs 2 channel control anyway on 27 Mhz.

I may dig that old off-road car out of the loft and charge some batteries up and see how fast it travels in a straight line on concrete and tarmac and also over a lawn, the wheels are quite large on it and it has basic suspension with a wide enough track to be stable so may do the job for launching a/c up to about 60'' span at a rough guess. As I recall it is fitted with a 540 motor which could be changed for a

600 to give it better acceleration and higher top speed and as I have four or five 600's in my box it may be worth the effort so if you hear any distant sonic booms or see blue clouds of smoke emanating from the eastern skyline you will know I got it wrong here in the U.K,

If I am still alive and kicking to tell the tail, many years ago in my impetuous youth we tried something simular to get a rather heavily built Wellington F/F off the floor but as the trolley was powered by three Jetex engines and no way to stop it the thing just kept going until it met something solid and immovable which was fine apart from the Wellington stuck in the cradle, the rest I shall leave to your imagination as it arrived at the wall of a disused bomb shelter...........

regards, Terry

Hi Terrence, May be fun but IMHO,not practical. I think you are referring to the takeoff

*d*ollies used by the U/C speed troops. Those speed jobs have power to spare, no batteries, and the length of the TO run is not a factor. A well designed dollie is a work of art.

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What about equipping the R/C trolly with a heading holding solid-state heli gyro? That way it could be driven to the launch point and orientated correctly, then left to its own wiles for steering.

A programmable servo on the throttle (obviously digital) could be used to get it going and then set to time out and throttle back, thus halting the trolly until retrieved, if I understand some of the new digital servo's programming capability correctly.

No, I don't know what I'm talking about. I'll just save everyone the trouble of telling me so.

Ed Cregger