Another MoBo Speed Record Flip

[jimbaerselman]

http://www.dailymail.co.uk/news/art...er-cheats-death-130mph-spectacular-crash.html

One day, designers of these speed record machines will discover aerodynamics.

Both flips described in this article were caused by these facts:
(a) Aerodymamic forces increase as the square of speed
(b) Darts only fly point first

Point (a) matters because speed record machines are more airborne than waterborne; the tiniest wavelet lifts them out or the water

Point (b) matters because, when flying through the air, objects will always try to travel with centre of gravity in front of the aerodynamic centre.

These machines are all weight at the back, with lots of "wing area" at the front. No wonder they try to fly backwards.

 

[DAKA]

Point of order !

We dont come onto your forum telling you have carp your sailing boat designs are
You should have your flappy things under the hull so you can see where you are going


I suspect the fuel tank was at the front to keep the bow down but it would be empty at the end of the run which backs up your theory, are you going to design a boat with the outboard at the front/centre and book coniston for a day .

 

[Lakesailor]

Only a week behind http://www.ybw.com/forums/showthread.php?378290-Eeeek!-Coniston-Water

 

[DAKA]

Only a week behind http://www.ybw.com/forums/showthread.php?378290-Eeeek!-Coniston-Water

Oh jeeze, come on guys, this is too much...............

not only do you come on here telling us how carp are boat designs are but now to start a spat raggie vers raggie
ON THE MOBO FORUM

You will find we dont bicker the same as scuttlebutts do , we are the gentlemen on the water !


Besides, in your week old link they blamed a gust of wind, jimba' blames carp mobo designers, the little tinker him.

 

[flaming]

http://www.dailymail.co.uk/news/art...er-cheats-death-130mph-spectacular-crash.html

One day, designers of these speed record machines will discover aerodynamics.

Both flips described in this article were caused by these facts:
(a) Aerodymamic forces increase as the square of speed
(b) Darts only fly point first

Point (a) matters because speed record machines are more airborne than waterborne; the tiniest wavelet lifts them out or the water

Point (b) matters because, when flying through the air, objects will always try to travel with centre of gravity in front of the aerodynamic centre.

These machines are all weight at the back, with lots of "wing area" at the front. No wonder they try to fly backwards.

Would a moth style wand driving an F1 style front wing work? Can see why you wouldn't want a permanent wing, as digging the nose in is probably an even worse result than trying a backflip... But if you could in effect have an areilon (sp?) on the front maintaining a constant height of the nose, would that go some way to solving the problem?

 

[jimbaerselman]

I suspect the fuel tank was at the front to keep the bow down but it would be empty at the end of the run which backs up your theory, are you going to design a boat with the outboard at the front/centre and book coniston for a day .

Nahh. I'd put a pair of stub wings at the back to move the aerodynamic centre aft of the C of G. That's why airplanes don't flip.

 

[TangaraToo]

But if you could in effect have an areilon (sp?) on the front maintaining a constant height of the nose, would that go some way to solving the problem?

You'd need an elevator (pitch) not aileron (roll).
Have often wondered why some sort of wing arangement connected to a gyro is not used. Would not have to be heavy and would not create much drag until it need to correct pitch. Is it against the rules for speed records?

 

[jimbaerselman]

Have often wondered why some sort of wing arangement connected to a gyro is not used.

"Auto stabiliser". Commonly used in aviation since early '50s. Requires auxiliary power systems to move the elevators.

In this case, the rate at which the flip accelerated shows that, when airborne, the boat had gross pitch instability. The size, power and precision of auto stabilisers to handle that deficiency would kill the budget.

KISS - stub wings. And I'd like 10% from the guy who adds 30% to the current record by using this idea . . .