Two fast steam boats one doing it’s fastest speed

[WindyParticipant @windy30762]

This is last Sundays video of two high speed hydroplanes with Bob Kirtley doing his fastest recorded run.

**LINK**

Hopefully we both might be quicker by the end of 2014.

Paul

[WindyParticipant @windy30762]

[Ian PParticipant @ianp]

Paul

Its not a subject I know much about but its very impressive!

Out of interest, how is the speed measured/certified?

Do you have any form of control once its released (radio or maybe a device on-board)?

Presumably the tether is responsible for sapping a lot of the potential speed? How much faster might it go if untethered?

Ian P

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Ian Phillips on 06/08/2014 09:58:33:

Presumably the tether is responsible for sapping a lot of the potential speed? How much faster might it go if untethered?

The force produced by the tether is almost at right angles to the direction of movement once a steady state is acheived so the effect on speed should be minimal. If it was untethered it may go marginally faster – but not for long.

Russell.

[Bob Brown 1Participant @bobbrown1]

Interesting to see the wash at the centre, looks like the start of a whirlpool

must go faster!

[WindyParticipant @windy30762]

Posted by Ian Phillips on 06/08/2014 09:58:33:

Paul

Its not a subject I know much about but its very impressive!

Out of interest, how is the speed measured/certified?

Do you have any form of control once its released (radio or maybe a device on-board)?

Presumably the tether is responsible for sapping a lot of the potential speed? How much faster might it go if untethered?

Ian P

Speed used to be measured with 3 separate stop watches and the average time over 5 laps of 100 metres taken now we have an electronic timing system.

The engine is flat out with no control and fuel runs out before the water.

Keeping the weight to the allowed limit (16lb dry) can be difficult otherwise there are various electronic aids I would like to have fitted.

I have just stripped it all down to repair some fire damage on that second 117 mph run caused by an experiment with an air-scoop that backfired.

The various dry lubricants have been successful in the engine considering its total distance run on one attempt was 31 100 metre laps conventional oils are lost through the exhaust ports as the piston is a slipper type.

Looking at some stills of K9 128mph runs the boat aerodynamics are about right for maximum speed i.e. front sponsons clear of the water and only the propeller in the water it is very close to flipping.

Next month will be another testing time so have to get the thinking cap on to try to go faster.

On some of the ex Soviet ponds they have a hole in the middle to dispose of the central backwash it's nearly level with the water surface.

Paul

Edited By Windy on 06/08/2014 12:39:08

[Neil WyattModerator @neilwyatt]

Good stuff, Paul,

Neil

[Ian PParticipant @ianp]

Posted by Russell Eberhardt on 06/08/2014 11:38:24:

Posted by Ian Phillips on 06/08/2014 09:58:33:

Presumably the tether is responsible for sapping a lot of the potential speed? How much faster might it go if untethered?

The force produced by the tether is almost at right angles to the direction of movement once a steady state is acheived so the effect on speed should be minimal. If it was untethered it may go marginally faster – but not for long.

Russell.

Apart from the centrifugal force I was also thinking of the drag caused by the line being pulled through air , although maybe that is insignificant compared to the craft itself.

Ian P

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Ian Phillips on 06/08/2014 15:15:15:

Apart from the centrifugal force I was also thinking of the drag caused by the line being pulled through air , although maybe that is insignificant compared to the craft itself.

Quite right. That's why I said that the force is almost at right angles.

Russell.

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