Thanks for the replies chaps, i'm glad to see it's not straight forward and I havne't just been a dunce! I think i've found a way around the L transform bit of it, but it's still proving difficult. Basically i'm trying to find the take off roll for a propellor powered UAV, but with only friction, lift and drag coefficients and mass and all the other constants. So I end up with an equation with acceleration as an unknown, velocity as an unknown, and some constants. Some manipulation made me think I had a solution, but it turned out to include complex numbers
.
I have tried MatLab with a simple ordinary differential equation, but the chart of velocity against time it returned went up to 90m/s, which can't happen because the prop exhaust velocity is only 32m/s!
When I find a way of writing the formulas down so that I can post them, I will.
Cheers,
Ginger
P.S. India Mike, you're correct, I was looking for the square of the first differential, not the formula for the second differential. Wow! Am I really talking about this at this time on a Saturday morning? Goodnight!
