Gravel Perf Writedown

[Coonman]

Hi Folks,

I'm not from your part of the world, but I think you might be able to answer a question....

If I can Take Off from say 4000 feet of asphalt, how many feet of gravel would I need?

many thanks

[tbaylx]

Well they pretty much look out the window around here, kick the ramp a bit to see how soft it is and say hmm yeah she'll go with 4000' today and t/o flap..most of the time they get it right.

[PappyJ]

Well they pretty much look out the window around here, kick the ramp a bit to see how soft it is and say hmm yeah she'll go with 4000' today and t/o flap..most of the time they get it right.


Well, that's about the most honest answer I've come across! :ok:

[clunckdriver]

Depends on what one is flying, in my little fabric taildrager with 31 inch bush tires it really doesnt matter, just keep the tail wheel out of the dirt and due to the high flotation of the gear it pops of in the same distance, however in the 421 with narrow high presure tires it can double the T/O roll, made even worse by the fact that one cant use full power till about sixty kts {unless of course you want to buy new props each day} The worst time is in the spring thaw, soft spots can pop up and spoil your whole day, most of the strips carry a caution, "soft in Spring", given a choice , sea ice or a frozen lake are a better option.as for how much should one factor in to the T/O distance? I think Pappy J got it right!

[NovaScotian]

Well as someone said, it depends on what your flying, what the runway graident is, temperature and if you have to worry about accelerate stop distances or not. I know in the B1900 we use 3500ft gravel strips and a normal t/o weight for us is about 16,900lbs at about -10c or so, the colder, the heavier we can go up to gross weight.

[PappyJ]

Although it was some years (read decades) ago, I recall that when I was flying in the north, we basically had one type of performance calculator, and one Northern Navigation system...W.A.G. and T.L.A.R.

W.A.G. = Wild Ass Guess & T.L.A.R. = That Looks About Right

Both seemed to work with reasonable accuracy.