RE: Back-yard speed record attempt aims for 2,000mph

[k-ink]

If you strap a large enough rocket on wheels I'm sure any speed is possible. But allowing the car and passenger to survive is another matter all together.

[R500POP]

k-ink said:

If you strap a large enough rocket on wheels I'm sure any speed is possible. But allowing the car and passenger to survive is another matter all together.

Hmm, what about the shock wave/ground interaction?

[Nick M]

R500POP said:

Nick M said:

Could they have been over-analysing things and just gone ahead and built the thing ??

Not whilst maintaining a decent level of safety, the forces at the speed we'll see with Bloodhound are an order of magnitude larger than those seen on Thrust SSC, I mean, have you seen the recent changes to the fin size in order to keep the cop well behind the cog.

Absolutely agree (mine was a rhetorical question really).

My ghast was well and truly flabbered when they were talking about how many rpm the wheels would need to run at, and how they would test them in a pit. And that's just one of the components.

I also recall some of the presentation about the aero package, where they were saying that one very minor change resulted in a rather substantial amount of *lift* at the rear. I think I'd rather trust an extensive CFD programme than the 'if it looks right, it is right' approach to engineering a car to travel at those speeds...

[R500POP]

Nick M said:

I also recall some of the presentation about the aero package, where they were saying that one very minor change resulted in a rather substantial amount of *lift* at the rear. I think I'd rather trust an extensive CFD programme than the 'if it looks right, it is right' approach to engineering a car to travel at those speeds...

Oh yes, a change to the rear delta (lower wishbone) angle of 1.5deg can give 5000kg of lift!!!!

[k-ink]

R500POP said:

Oh yes, a change to the rear delta (lower wishbone) angle of 1.5deg can give 5000kg of lift!!!!

Fuuuuu.......... !

[R500POP]

And from 1000mph the deceleration to zero is equivalent to stopping a regular car from 60mph in 1second, but for a sustained period of around 20secs.

[tank slapper]

Nick M said:

Could they have been over-analysing things and just gone ahead and built the thing ?? Well, given the fun and games they had with Thrust SSC and the beating that took every time they ran it, no, I don't think so. And Bloodhound is a big step up again in terms of the speed they're aiming for.

Interestingly, they spoke about making a decision to stop aiming for the *best* 1,000mph car, and simply go for building the *first* car to break the 1,000mph barrier.

Agree with this. The Bloodhound team actually have experience of operating a supersonic car, so I doubt they are doing anything that isn't necessary as they know how difficult it is. At lower speeds, rule of thumb and seat of the pants operation might be sufficient or even successful, but the forces and energy levels involved with going that speed on the ground make me think that approaching it that way would result in disaster.

[R500POP]

The primary consideration in ant decision is the safety of Andy, we can't go killing him.

[Nick M]

R500POP said:

The primary consideration in ant decision is the safety of Andy, we can't go killing him.

That, and how to accommodate balls the size of space hoppers...

[Chris71]

Good luck to him. I hope he's got a really good grasp of transonic and supersonic aerodynamics otherwise I fear he'll go the same way as that (possibly fictional?) individual who strapped the JATO rocket to his Chevy Impala.

Not that I'm suggesting the bloke in the Impala got to anything like that speed before his plan came unstuck...

[CraigyMc]

Chris71 said:

Good luck to him. I hope he's got a really good grasp of transonic and supersonic aerodynamics otherwise I fear he'll go the same way as that (possibly fictional?) individual who strapped the JATO rocket to his Chevy Impala.

Not that I'm suggesting the bloke in the Impala got to anything like that speed before his plan came unstuck...

Entirely fictional.

http://www.snopes.com/autos/dream/jato.asp

[Chris71]

CraigyMc said:

Chris71 said:

Good luck to him. I hope he's got a really good grasp of transonic and supersonic aerodynamics otherwise I fear he'll go the same way as that (possibly fictional?) individual who strapped the JATO rocket to his Chevy Impala.

Not that I'm suggesting the bloke in the Impala got to anything like that speed before his plan came unstuck...

Entirely fictional.

http://www.snopes.com/autos/dream/jato.asp

I had a feeling that would be the case. Still, attempting to do 2,000mph in a homemade rocket car is likely to have a similar outcome, I fear.

[R500POP]

Chris71 said:

I had a feeling that would be the case. Still, attempting to do 2,000mph in a homemade rocket car is likely to have a similar outcome, I fear.

As I think I may have said already, he's done the typical american trick of taking somebody elses target & doubling in. Having seen the gargantuan effort that we are putting into a target of 1000mph there is not a chance Waldo will hit 2000 mph with Sonic Wind.

[CraigyMc]

R500POP said:

Chris71 said:

I had a feeling that would be the case. Still, attempting to do 2,000mph in a homemade rocket car is likely to have a similar outcome, I fear.

As I think I may have said already, he's done the typical american trick of taking somebody elses target & doubling in. Having seen the gargantuan effort that we are putting into a target of 1000mph there is not a chance Waldo will hit 2000 mph with Sonic Wind.

I was about to take a pop at you for saying "...the effort we are putting in..." as if the whole of the UK was involved, before realising that you are in fact directly involved in the development of Bloodhound SSC.

Well done to you sir.

C

[thinfourth2]

R500POP said:

Chris71 said:

I had a feeling that would be the case. Still, attempting to do 2,000mph in a homemade rocket car is likely to have a similar outcome, I fear.

As I think I may have said already, he's done the typical american trick of taking somebody elses target & doubling in. Having seen the gargantuan effort that we are putting into a target of 1000mph there is not a chance Waldo will hit 2000 mph with Sonic Wind.

I disagree

Parts of him may achieve 2000mph

Just not all of him and the car in the same direction at the same time

[R500POP]

CraigyMc said:

I was about to take a pop at you for saying "...the effort we are putting in..." as if the whole of the UK was involved, before realising that you are in fact directly involved in the development of Bloodhound SSC.

Well done to you sir.

C

Thanks, it makes a really pleasant change to get up in the morning & actuall want to go to work. In my last job I started at 7am & knocked off at 3:30, here I am, having started at 7:30am, still working now & not complaining!!

[AreOut]

thinfourth2 said:

I disagree

Parts of him may achieve 2000mph

Just not all of him and the car in the same direction at the same time

even if he had all know-how and money of this world(yes, literally) there is no way a free-moving (=not on rails) vehicle with wheels is going to get close to 2000 mph on the ground in one piece(remote controlled vehicle too, there is no need to kill someone even if that person is stupid enough to try that), it's just physically impossible with current materials and will remain such for a long time, as it is physically impossible for a man to jump 3 meters up in the air (without aids)

the only theoretical possibility of something similar is putting the rocket engine on a hovering vehicle but then it would technically be flying...

[motoxyogi]

Schnellmann said:

Morningside said:

This is the sort of fighting engineering spirit we had here.
Frank Whittle, Christopher Cockerell, Malcolm Campbell etc. NO computer CAD and yet they got built and worked.

Maybe he IS mad but being a 'garden shed' builder I say good luck to him.

Computer/CAD were not available for Whittle et al. Had they been, are you sure they wouldn't have used them? Did they deliberately ignore the best information/resources that were available to them in their time?

I support the spirit behind the idea but assume chances of success are pretty minimal. Actual, I assume chance of him trying are pretty minimal and think this is just a way of drumming up publicity for himself.

+1
You can bet your bottom dollar that each and every one of those guys had libraries worth of notebooks filled with calculations and experimental results, sliderules worn down to nubs and many, many well thumbed copies of engineering and physics journals.
While CAD and FEA software don't supercede engineering know-how and a brilliant mind, they cut-down the workload immensely.
On the otherhand the Soviets proved that it is possible to make cutting edge jet designs comparable with the American offerings, using fairly standard materials and little computer simulation.
I wish this fellow the best of luck if he does go through with it, but I'm not optimistic.

[Mattygooner]

It's no good, i have looked in every picture and i can't find him.

OT, i fear this will end with a Patriot putting him out of his misery somewhere over Bermuda..... But good luck to him.