Just wondering if any of you engineers could estimate the nm produced by a kite being sent hard in 35knots compared the the force produced by an SS ute with your foot on the floor?
Would you then need to do it per kg of ute vs per kg of human to get a comparison?
(i'm not an engineer, happy to be called a retard for not understanding how any of this stuff works)
a kite cannot produce any measurable nm... nm is a measure of torque, a force causing rotation...
other than that i have no ****en idea how to work it out, lots of variables that could affect it. But I know I can still edge harder than my kite in 30-35knot, but behind a wakeboat (that have less power and traction than an SS) there is no way I can overpower it with my edge
Googled this somewhere
Force, F = A x P x Cd (Nm ton-force*m 0.000101972)
A = The projected area of the item,(Sq inch) 1inch = 0.0254 m
P , Wind pressure (Psf), = .00256 x V^2 (V= wind speed in Mph) 1 knots = 1.15077945 mph
Cd , Drag coefficient, = 2.0 for flat plates. For a long cylinder, Cd = 1.2.
My guess at changing letters to numbers then converting them came up with this
12m kite in 30 knots = 1.38 tonns of force
9m kite in 30 knots = .78 tonns of force
with my S*** maths I guess my guess would be wrong.
Saul... it's your turne
f=ma
frame by frame a take off. see how fast the kiter accellerates 0m/s to xm/s in t.
plug that in there you go. rough but a pretty good guide oh and you need to know the weight of the kiter (mass *9.81)N.
Hey Wishy,
WOuldn't you be actually trying to measure force times accelleration over time rather than nm. I'm no engineer either. 
Are you interested in working out how much power was expended when the 9m Edge pulled you out of your footstraps and flung you skyward today? 
DM
I think he wants to know the force that dragged him when he luffed then hot launched my 7 fuse.
Also you should have seen NickT yesterday.
He was sending his 7m fuse as hard as possible into 40 knot gusts and flying into the stratosphere. There were four of us laughing on the beach ready to catch him incase he covered more than 500m in one jump and landed on the beach.
^^^
Great article, though a sad indictment of Australia's lack of a mainstream futurist business culture. Still there are some amazing pockets of innovation here, just not as linked up as in the states.
As other posters have suggested, rather than trying to compare the force that the kite generates with the torque (force x distance from axis) of a ute, comparing the power generated over the 0.5 -1 seconds of initial takeoff to the power of the ute at say 5000rpm would be more of an apples and apples comparison.
However, the ute is going to slay the kite, until you factor in weight. On a power to weight ratio the kite will do a lot better, though the boosting power is an artificial peak created by the kiter riding in the opposite direction to the kite, and clearly not sustainable for more than a second or two. On the other hand, the ute relies on a finite energy source and so in a larger frame of reference, it's power-generating abilities are less sustainable than the kite's.
>>> Todd
Wouldnt that be the priest defrocking the schoolgirl ??
Or am I just an ol'fashioned sort of guy 
>>> Wishy
It goes like this:
- multiple your total weight times your speed at take-off
- divide that by the height of the elevation times the distance covered
- Nb : minus your speed at landing
- then take the square root of the windforce at the time multiplied by surface area of your body (to allow for wind resistence)
- deduct 10% for exaggerated height
and there you have it.
Thanks anyhow Saul - all covered.
How about measuring the G force?
I've been launched pretty damn hard with an 8m in 35knots... not as quite the same as being in a WRX or evo with 'launch mode'.
Then there is the whole foil vs LEI debate. A foil flying mate has switched over to LEIs and claims that foils yank you upwards much harder (flysurfer psycho 4 vs ozone c4).
Then again it shouldn't be too hard to figure out the force (or whatever the correct physics term is) to throw 90kg 10meters into the air.
mike
What do ya mean wishy? They both got bridles
Knowing the gforce you get from a kite would give the car a run for it's money I reckon.(at least for half a second)
You can compare the acceleration between the ss and a kiteloop.
An ss ute will accelerate on average ~5m/s^2, (just over 1/2 a G), to 100kph. But it's initial acceleration will be a fair bit more (it probably maxes out at about 2G, but that's just a guess).
I have a video of me doing a kiteloop on that really windy day about 2 or 3 weeks ago in about 35 knots, and I figured that I went from 0-50kph in 1 second, which is an average of 1.5G (15m/s^2).
The force of that is: F = mass x acceleration = 75 x 15 = 1125 Newtons.
Whereas an ss ute that weighs 1.7 tonne provides ~ 32300 Newtons of linear force (correct me if I am wrong - I don't really know if that makes sense).
To compare the feeling that you experience you can compare the rate of acceleration.
It is difference in speed over time. Calculated using the interweb:
www.smartconversion.com/unit_calculation/Acceleration_calculator.aspx
Using a quick ballpark calculation (try your own guess at the kiter numbers)
Kiter cruising at 15km/h boosts to 50km/hr (linear speed in the direction of pull) in 1.5 sec = 6.5 m/s/s acceleration
if you reckon you get to 50 in 1 sec that makes it 9.7 m/s/s (pretty close to gravity/freefall acceleration??)
Compared to
SS ute 0-100 in 5.6 secs = 5m/s/s (average over the 5.6 secs)
saying that the ute will be faster than average in the 15-50 range
so the stuck to the back of the seat feeling in that range will be pretty close to the whip from a good boost.
the difference being you are pulled from the waist or arms (if ur an unhooked hero) out in the air, its short, you get a view from the top and get the added rush of wondering if you are going land with both knees intact - pretty similar to a ride in an ss with a bogan i suppose
my 2c
interested to know what your thoughts on the speeds and time are, maybe the gps sailors can help
Put your iphone in a waterproof bag and use the G force app. Some sort of accellerometer.
Just a thought!
DM
