50mph in 7.9sec

Rolling start 4.7 mph. Top speed 49.9 mph. Time 7.9 sec.

Kite 9m Genetrix Hydra

Buggy Dominator 4 - weight 73Kg / Rider weight 92Kg / Gross 165Kg (363lb)


I had a midweek buggy session on Wednesday 6th May at the Purley Way playing fields. The wind was up and I was there primarily to test a camera and GPS mount I'd been working on. I had bought a new Sony camcorder to record better quality video but the winds brought sunshine and showers so I decided not to risk mounting it to the buggy.

It was a fun session, high winds, sunshine and wet dandelions. Lots of sliding about and last second risky moves which saw me deploying the chute on occasions. Powersliding to a stop is not very effective for me on grass, whether it's wet or dry. Sending the kite 180 degrees behind me to help slow down in a hurry is a practice I've become accustomed to over the years.

I see a guy at the school fence standing there looking my way. He's wearing a lab coat, probably a science teacher. I hope it's not out of concern for the kids but out of curiosity. I don't normally ride on this part of the field as it has more goal post per square inch than the rest of the playing fields and it's a relatively small and busy section with a kids playground, a skate ramp, nearby houses and a busy tree lined road on two sides where the field ends in a point but today being a weekday it is quiet.

However at 3pm a little over one thousand school kids will empty onto the fields. I have just 40 minutes left before I must taxi back to the hanger and cool my engines. I achieved 45mph earlier in the day but with a little luck I might find a gust with my name on it and do better.

I start the speed run in the far corner. The kite is flying over the trees and in danger of stalling in the wind shadow created by the school buildings. I do this because I need as much run-up as possible. This area is my only real option for speed, after an hours riding I discover that the wind is being funneled here.

My lowest speed of 4.7mph is somewhere around here and I think it is shortly after the turn but it takes the GPS about one or two seconds to update it's current speed to the screen. Please account for this slight delay when watching. I'm getting my speeds direct from the GPS unit so that anyone who wants to can stop the video at any time and check to see if my own mph counter marries up but in reality I'm both starting my speed run and reaching the top speed sooner than indicated in the video. Either way the measurement is still the same.

Acceleration was quick, very quick!
The moment the kite emerged from the wind shadow it was off. The kite had hit a sustained gust and I was being pulled forward in the seat, my feet pressed against the pegs. I don't think the wheels could find traction on the wet grass. I felt the rear wheels ski along rather than roll. The road was coming up fast and the gradual slip downwind was putting the kite close to the trees. Luckily it was dry just enough to steer upwind albeit gradual. It had been raining on and off all day but the playing fields drain impressively quick. An hour earlier it chucked it down making upwind turns impossible.

How did I come up with 7.9 seconds? This is an easy measurement to make within the video editing software. I examined the footage carefully until I came across the very first frame where the GPS display's 4.7mph, just as it ticks over from the previous reading and cut it. I then did the same for the very first frame where I see 49.9mph. The editor is then able to precisely measure the length of that clip, 7.934 seconds to be exact.

Maybe not an acceptable method of measurement for any league table should one ever exist but good enough for this video.

I included my own counter to show mph to compliment the GPS unit as the picture quality isn't great. The vibrations and overcast sky did not help. I mirrored the readings directly from the GPS frame by frame which took forever and a day. I also included a third party 8 digit timer which also matches up.

There was a heart stopping moment when my foot slipped off the wet foot pegs at speed but fortunately the front wheel did not turn too far in either direction due to the wet grass and I regained control.



https://www.youtube.com/watch?v=R1Ujw5lmQHM

Thanks! Glad you all liked it. Sorry for the poor quality.

Quote: Originally posted by Cheddarhead

Fantastic speed! Nice runs! Wish I had a place like that to ride. Do you know of anyone that has tried to run Landsleger wheels on grass? Always wondered if the dry lake bed type wheels would give less resistance on grass.

Thanks! I've seen where you ride. It looks like a fairly long airstrip with a roller coaster at the end. I really wish I could park right next to the grass like you do. It would save me pushing my trailer out onto the grass. It weighs a tonne.

My friend David aka (Old_Guy) uses the Landsleger wheels on his GT race and often joins me at the Purley Way playing fields. He let me have a go of his bug and I nearly tipped over. In fact I think I may have bailed just in time before it did.

They bite very hard on grass. Bit scary for me but that might be due in part to riding a strange bug that isn't setup for me. I bet they provide great upwind performance in good wind.

He joined me back in March in little to no wind, sub 5mph. He was static flying in the buggy and down looped his 9m Zebra Slope, it pulled the bug over. He busted a rib or two and hasn't returned yet. I must give him a call. My bug would have slid a little. I like tyres that have a 50/50 balance of grip vs slip on grass.

I used to run discs at Purley a few years back but they went through a new set of bearings nearly every session, probably because the camber wasn't setup correctly.
Yeah they had a very low rolling resistance going forwards and slideways. The tyres were very thin and bald. Both the wheels and tyres came off a vintage Suzuki GSX 400 motorbike. I still have them but now with new heavy modern tyres. They are for sale if interested but all three wheels together total 32Kgs!!!! Only 100 miles on Ivanpha and they're untouched.

Kinda what I figured with the Landslegers on grass. Seems to always be a trade off. I can still slide my rear with barrows but it takes alot to do it. I wouldn't want to always be rolling the bug, that wouldn't be any fun I'm pretty happy with what I have at the moment:D

Damn...I think that's quicker than my Toyota Camry

Very impressive indeed!

Gotta say...I really didn't think LEI's had that kind of accerlation. It would be really interesting to see what a Vapor could do in those same conditions. I bet it wouldn't be that much quicker...

Quote: Originally posted by lunchbox

I bet it wouldn't be that much quicker...

and certainly not as kind!

Quote: Originally posted by Cheddarhead

Kinda what I figured with the Landslegers on grass. Seems to always be a trade off. I can still slide my rear with barrows but it takes alot to do it. I wouldn't want to always be rolling the bug, that wouldn't be any fun I'm pretty happy with what I have at the moment:D

No worries. Yeah barrows are supposed to be the best for grass, followed by BFL's.

Quote: Originally posted by lunchbox

Damn...I think that's quicker than my Toyota Camry Very impressive indeed! Gotta say...I really didn't think LEI's had that kind of accerlation. It would be really interesting to see what a Vapor could do in those same conditions. I bet it wouldn't be that much quicker...

It's a Genetrix Hydra!

Yeah, the Vapor and other fixed bridled foil race kites are just too efficient to be quick off the mark.

They sit too far forward in the window where there is the least amount of power to be quick. Sometimes riders will apply brake input to their foil race kites to bring the kite back into the power zone for a temporary boost. Maybe that's something they can try but a depower kite will always outsize theirs. The advantage of the Vapor and such kites is in their low drag at high speed which keeps them closer to the crosswind.

The Vapor might be faster but not necessarily quicker.

If you want to be quick then you need plenty of grunt, that is, kites that sit deep in the window or kites that can be made to sit deep then sit forward later (depower), both quick and fast.
The Genetrix Hydra is particularly good at this with Sebastin Cattelan using the same 9m to be the first kitesurfer to 50kts and then 55kts at the Luderitz Speed Challenge, Namibia.

Nice!

The only other time I have seen acceleration like that was at sunset beach, OR with Eli using the sub 100 yards of hard pack in a cross onshore wind to get to 49mph fast

Quote: Originally posted by RonH

Nice! The only other time I have seen acceleration like that was at sunset beach, OR with Eli using the sub 100 yards of hard pack in a cross onshore wind to get to 49mph fast

Thanks! Considering cross onshore takes a little longer to get you going that's impressive!


Thanks again everyone.