Crash Analysis

[Richie]

that trophy belongs to the UK...get it back for us PLEASE !

[quicksilver-wsr]

We're on it and we'll stay on it until we reach a conclusion one way or the other.

[Renegadenemo]

Been doing a little more research of late and here's an interesting one for you. According to the man who stuck his nose into a Beryl engine for me this week it spins the opposite way to an Orph' and therein lies two problems.
One is that the behaviour of the boat so far as the gyroscopic forces are concerned would be completely reversed and unfamiliar to Donald after so many years of it reacting the opposite way, and the other is that a right-hand turn would pick the bows out of the water whereas before they'd have been pushed in by the same control input.
Add that to the significant weight bias to the left (look which way she wallows as she sinks), increased drag on that side due to the rudder being larger than the fin and the free surface of fuel in the tank, not to mention the substantial quantities of Avtur housed down the left in the aux fuel tanks with their booster pumps, and she'd want to turn left. The dented spar partly offset this by trying to fly but at the aerodynamic limit the gyroscopic precession of the engine would pick the right sponson up especially if the boat was listing slightly to the left. Intriguing...

[malcolm uk]

that trophy belongs to the UK...get it back for us PLEASE !

Probably not an accurate statement, but the sentiment is well stated.

Hustler - the boat which took the record from Donald with Lee Taylor at the controls was also wooden.

There have not been many WWSR metal boats or indeed modern composite construction boats, yet in other maritime classes these materials have been used in great amounts in the period since the 80's.

Malcolm

[Renegadenemo]

Had the pleasure of being amazed by by a dynamic, mathematical model of K7 on Monday, a model into which you can introduce wind and waves and punch the boat around at will as she's running at 300mph.
What's amazing is that she's actually very difficult to get out of shape even at such speeds. Give her a shove or chuck a wave at her and she quickly damps out the upset. Forget engine flameouts, dented spars or any other previously considered phenomenon because about the only thing that'll get her properly in trouble is getting the lake surface in harmony with her natural frequency in pitch, otherwise she stays stuck down. It was quite an eye-opener!

[Mike Bull]

Must admit, from the quick run-through of it that I heard, it's utterly fascinating, very compelling, and far more likely sounding than duck dents etc!

[orgster1]

So are we back to the "Wash" theory again? Or the submerged Log?

[Renegadenemo]

So are we back to the "Wash" theory again? Or the submerged Log?

You can hit it with a log and it'll damp out the upset quick as you like and even the wash wasn't necessarily the problem. The boat was excited in pitch on the first run too so it could simply be the water conditions on the day.

[orgster1]

(You can hit it with a log and it'll damp out the upset quick as you like and even the wash wasn't necessarily the problem)

The pitch thing "Y"axis seems pretty much a good explanation Bill because I have always thought if it had been a submerged log and severe enough to make the boat airborne then it would have thrown the boat to one side or the opposite way to which ever sponson hit the log (Like a car being thrown onto 2 wheels). And surely the boat would have left the water with one sponson high in the air? But as it seems the boat was pretty level when it became air borne then it would mean hitting a log square on and the log or tree would have to be the full width of the boat? Did they find any lumber that size on the day? and it was only damage to one sponson wasn't it?. Also if it had thrown one sponson high before takeoff wouldn’t the other sponson try to submarine which in turn would cause the boat to cartwheel rather than lift levelish? Then there’s the sponson walking theory, If the boat had been sponson walking to the severity it would take to make it airborne it would have at least left the water at a 45 degree angle ("Z"axis Yaw) I would have thought, and so by the time it was upside down it would be side on facing in the film (just thinking tank slap here on a motorcycle and how it gets completely out of shape! starts at the front and works its way down the full length until it just literally throws you off (like a dog shaking itself it starts at the head and works its way down to the tail) and all this leads to pitch and roll and yaw all at the same time. Or If the boat was rolling from one sponson to the other "X" axis( if that's what sponson walking means?) then it would if anything at worse rolled over(using the 2 wheel thing here again) onto its side? But then we have the one sponson trying to submarine again and the cartwheel thing! So yes for me the pitch thing "Y" axis makes perfect sense as a backwards and forwards motion until it became that severe it lifted the front of the boat. Just my opinion of course which I am sure will be seen as totally worthless by some people

[Renegadenemo]

So yes for me the pitch thing "Y" axis makes perfect sense as a backwards and forwards motion until it became that severe it lifted the front of the boat.

That's about the size of it only this wasn't just another case of someone saying, I think what happened is this... The findings come from directly modeling K7's behaviour at 300mph and discovering that that's about the only way to get her out of the water. And it's a bit like pushing your kid higher and higher on the swing with one hand, it's frightening how small a wave you need to set it off so long as the frequency is correct.