World's Fastest Boat?

[Jay Turner]

Ken is at it again. Check out this video of recent tests of the new boat Aussie Spirit. It's a large file (5 Meg).

http://www.screamandfly.com/video/warby_test/warby.wmv

Go here for more info on the new WWSR attempt.

http://www.kenwarby.com/

[seadoojumper]

Looks like a fast boat. Hopefully they can break the record.

[AndyKunz]

... without getting hurt or worse.

Andy

[JfromJAGs]

I would'nt want to sit in this boat.

I mean I would'nt want to sit directly in front of a 9000 HP turbine anyway, but especially I would'nt want to sit in front of one AND have an open cockpit.

Not even talking about how narrow the boat is and how much surface it has infront of the CG.

This is definitely a ride on a canon ball.

I really hope nobody gets hurt.

[Happy Amp´s Ch]

Where are your nerves Joerg,
have you seen the Spirit of Australia runing at full throttle bouncing from one sponson to the other.

The Cafe drive on the river is very smooth.

I am allways wondering that no one has ever build one of the fullsize recordboats in modelscale and test it for SAW.
Hustler and Spirit of Australia have shown there potential to go this speed and Crusader was tested as a 1:6 model with solid rocketpower up to 97 1/2 m.p.h. having no problem.

[JfromJAGs]

I would argue the opposite way.

Scale speed of our T hydro is aprox. 450mph (considering 1:10 scale). It was rock solid AND even used a propeller instead of a turbine.

[Jay Turner]

Some things cannot be exactly scaled up or down successfully. Regardless of the scaling changes we make in the size of our models, we cannot scale time up or down. The interaction of the model and the water is a function of time and that can't be scaled exactly.

Weight enters the picture as well. If Joerg's rigger weighed 8 lbs, an in-scale "real" boat would weigh under 800 lbs. The Aussie Spirit weighs considerably more than that, so the lift required to support it clear of the water is far different than a direct scaling of a model would produce.

I concur with Joerg, mainly because of the open cockpit. Unlimited Hydros, and even many limited hydros, went to enclosed cockpits years ago, and it saved lives at <200 mph. At well over 300 mph, a crash in an open cockpit boat is an invitation to a dramatic, quick death. :(

[JfromJAGs]

Jay, volume (weight) scales to the power of 3, so an in-scale real boat would weight 8000 lbs.

I would guess the Aussie Spirit is lighter, as unlimited hydroplanes are around 6000 lbs.

But you are right, this scale speed stuff is only a rough guess.

[Jay Turner]

...volume (weight) scales to the power of 3, so an in-scale real boat would weight 8000 lbs. Of course it does...the formula is SxSxSxW, where W=weight and S=scale. :rolleyes:

[JfromJAGs]

I found a weight for the Aussie Spirit: 1600kg = 3500 lbs. The jet engine should have more thrust than that, so just in case it would be needed, the Aussie Spirit could go up vertically.

For some reason this remainds me of the 1995 Darwin Award.

[Ernie Lazenby]

Well I have scratch built working models of Spirit of Australia and Crusader; However I have no intention of wrecking them by pushing them too hard.

I am about to embark on building a 1/6th scale Spirit of Australia to be powered by a Wren Gas Turbine. I am aiming for a total weight of around 14 lbs thus acheiving at worst a 1: 1 power to weight ratio. Watch this space!
I had intended to do another Bluebird K7( I already have two) powered by GT but K7 Models but are getting as common as seagulls so I am going for the more difficult and unique model.

My electric poweerd model of SOA tramps exactly like the full size boat did.

BTW I got an indirect message from Ken Warby re my 1/8th scale model of SOA and hes impressed with it.

[Happy Amp´s Ch]

Hey Jay,
but see that Peter Du Cane the designer of the Crusader makes testrunn with a 1:6 modell .If the scalefactor is not to big it´s not bad working.The fullsize Crusader goes easy the calculated scalespeed.Also the Noris Brothers designing the Bluebird do modeltestrun with tethered boats.The Froude formulas are right .
Ernie ,
your boats are to nice to race them hard to the limit.This was the reason for me to build my SAW Canard with some in the design like the Crusader.

[Jay Turner]

The problem is Christian, the true scale speed is not a direct proportion - for a 1:10 model you cannot divide the full scale speed by 10. The correct scale speed can be found thus:

Square root of the scale (1/10) x actual speed

This is because time is not scaled down the same as dimensions are. The time units are scaled down by a ratio of the square root of S.

For a 300 mph full-scale boat, a 1/10 scale model would run 94.8 mph, not 30 mph. It is not as simple as common sense would have the tyro believe.

[AndyKunz]

And then there are all the non-scalable factors such as the relative densities, adhesive forces, etc.

Andy

[Andrewg]

Joerge have a look at the video of the 318 mph record runs. They were done with a shovel nose.

A year later that boat ran 405 mph one way in testing of the afterburner which was not used to set the record.

Ken describes it as like driving a Volvo on an expressway.

It was wind tunnel tested to 450mph

The new boat has less area at the front of the boat.

Ken will not run the boat unless it is safe his development programs are usually a couple of years long once the boat is built.

The cockpit is open BUT it is FIM approved. Ken prefers it as he has always driven open boats. He feels at 400 mph you either come back or you are dead.

And you are right about the motor in a recent interview on the national broadcaster Ken was asked what would be going through his mind if he got into trouble and he replied "a westinghouse jet engine!"

[JfromJAGs]

@Jay, when I write the scale speed of the T hydro was 450mph then this is 143mph * Sqrt(10).

Ken got my deepest and true respect for what he did and is going to do. I'm only afraid he's going to kill himself. Too many others have done it before.

I'm not sure if there is a chance to survive at 400mph, but if there were any, I'd try to do anything for it. It's better to be a living legend. Noticing how safety improved in F1 even in the last 5 years I would check back with them.

[Jay Turner]

Of course you got it right Joerg, but many others don't understand why you just don't mulitiply by the scale factor.

I'm not certain that there is much difference in a crash at 300 mph or 400 mph - Donald Campbell died instantly at under 300 mph. Safety capsules have changed the face of Unlimited and F1 racing as far as injuries and fatalities go - why a well-funded SAW effort eschews them is a mystery to me. Perhaps the Aussi machismo has something to do with it in Ken's case. :(

In any case, I wish him well in his attempt and in his lifespan.

[MPR Arthur]

I'm afraid Kens record boat is too narrow. Therefor he had no choise but to put the turbine very high, causing it to have a high point of gravity. Joergs record boat designe would be a lot safer in my opinion.
Arthur.

[AndyKunz]

Turbines are very light - they're mostly air.

The CG may be high, but so is the thrust line.

Andy

[Happy Amp´s Ch]

Jay,the formula :Square root of scale factor X modelspeed is the Froude formula ,he was the founder of the basic of comparison.
The Crusader model runs with 98 mph as a 1:6 scalefactor so this was 240 mph of the full size boat.The Original run this speed befor the front shoe became weak and broak.Peter Du Cane told this to John Coob befor he start his run .He wants to take the boat back to the shipjard and make the shoe stronger,but Coob wants the record and the shoe faild.
For my opinion the boat is not to narrow.If the sponsons are to wide ,the working arm lengh is to big and so little afect can rise the sponson out of the water and turn the boat.One single step in front dosn´t do this.