Bloodhounds wheels go on the lathe

[Ady1Participant @ady1]

Bloodhound: Superwheels for supersonic car go into production

[Ady1Participant @ady1]

[KWILParticipant @kwil]

According to The Engineer magazine thay have also tested the composite "armour" to ensure that should any wheel shed a slug of aluminium it does not penetrate the cockpit, it did not.

Wheels are forgings to ensure the grain is radial, like spokes, for max strength.

[martin perman 1Participant @martinperman1]

My Brother and I made small donations a couple of years ago and we get regular news letters via email that make interesting reading on how the project is going.

Martin P

[Nick GrantParticipant @nickgrant21535]

The bearings must be quite something to cope with that!

[pgk pgkParticipant @pgkpgk17461]

Posted by Nick Grant on 15/03/2015 13:12:17:

The bearings must be quite something to cope with that!

A jet engine does around 10K rpm, a dental turbine to 500K rpm and Trust is panning on wheels at 10.5K RPM so perhaps not such a biggie…

What percentage of drive goes through the wheels.. or ar they just there to stop the chassis scraping…?

[martin perman 1Participant @martinperman1]

This car has three engines, the jet to power the car up to a certain speed the rocket to assist through 1000 mph and a ford cosworth whose sole job is to power a pump to supply fuel to the rocket, no drive goes through the wheels.

Martin P

[Nick GrantParticipant @nickgrant21535]

Posted by pgk pgk on 15/03/2015 13:53:28:

Posted by Nick Grant on 15/03/2015 13:12:17:

The bearings must be quite something to cope with that!

A jet engine does around 10K rpm, a dental turbine to 500K rpm and Trust is panning on wheels at 10.5K RPM so perhaps not such a biggie…

What percentage of drive goes through the wheels.. or ar they just there to stop the chassis scraping…?

True but surely wheel bearings would be taking a far greater load than either of those? I was thinking you would need a huge amount of downforce to keep this thing on the ground at those speeds.

[Swarf, Mostly!Participant @swarfmostly]

Hi there, all,

I worry about projects like this one! I'm sure I read somewhere that one of the earlier (1930s?) land speed record attempts failed because the driver attempted to steer the car at speed – the gyroscopic effect resulting from the high RPM of the high moment of inertia wheels caused the yaw moment (steering) to be transposed to a roll axis moment (precession) which turned the car over.

How have more recent attempts addressed this problem?

Best regards,

Swarf, Mostly!

[martin perman 1Participant @martinperman1]

I just been and had a look and the wheels are designed for 10,500 rpm.

Martin P

[Phil WhitleyParticipant @philwhitley94135]

Pendine sandsm, J G Parry -Thomas? http://en.wikipedia.org/wiki/J._G._Parry-Thomas

Phil

[KWILParticipant @kwil]

Jet engines run at rather more than 10K rpm. A model turbine runs in excess of 100K rpm and they certainly do not self sustain until around 25/30K rpm and then they spool up from there.

[pgk pgkParticipant @pgkpgk17461]

Posted by Nick Grant on 15/03/2015 14:31:07:

…..

True but surely wheel bearings would be taking a far greater load than either of those? I was thinking you would need a huge amount of downforce to keep this thing on the ground at those speeds.

I'd have though the whole point of downforce here is just to prevent lift from flipping it over – as opposed to pinning drive wheels to the ground. So while there will be aspects of bunce and buffet on the smoothest terrian they can find I'd expect th downforce to be less than first guesses might suggest – or it'll end up a two deep scars across the sand and four flat bottom wheels

Surpersonic speeds do very weird things to centres of pressure over surfaces. Fastest i ever piloted was a single engine prop job in some basic aerobatics. Six times as fast in experimental stuff is nutter territory.

[John Stevenson 1Participant @johnstevenson1]

End of the day these people will some some real experts advising them.

They won't be using forums for guesswork advise no matter how well educated the guesser feels they are

[Nick GrantParticipant @nickgrant21535]

Posted by John Stevenson on 15/03/2015 17:03:11:

End of the day these people will some some real experts advising them.

They won't be using forums for guesswork advise no matter how well educated the guesser feels they are

I don't see anyone trying to advise, just a general appreciation of the engineering involved and how difficult and dangerous it will be.

Rather patronising to suggest anyone here would think we know better than the guys and girls doing the work to be honest.

Edited By Nick Grant on 15/03/2015 17:51:44

[JAParticipant @ja]

I visited the project last autumn and went to a lecture on Thrust SSC after its successful record breaking attempt. Essentially the people who worked on Thrust SSC are now working on Bloodhound so there is a good continuity of knowledge. However, when questioned, their spokesman did not think they would work on another project because they were getting old.

Thrust SSC did have a problem after it went above Mach 1 – the external shock waves lifted the surface of the salt lake ahead of the wheels. This is now well understood and should not be a problem.

Comments on bearings – helicopter gas turbine bearing speeds can exceed 30,000 rpm. Gas turbine bearings have a completely different set of problems to high speed wheel bearings – the loads on the bearing are very low which can lead to skidding of the balls or rollers and the environment can be very hot. Great care is taken to cool the bearings at the hot end of an engine so that the oil lubricating the bearing does not catch fire.

If you get the opportunity of visiting the project it is well worth going. However I believe visits may soon curtailed to allow assembly of the car.

JA

[Ady1Participant @ady1]

I was thinking you would need a huge amount of downforce to keep this thing on the ground at those speeds

…but not too much or you turn the car into a plough…. while too little means she flips front over back

Presumably they have some sort of dynamic spoiler system, still one heck of a challenge though, especially at 1000 mph

[blowlampParticipant @blowlamp]

I don't want to be a killjoy, but this looks too dangerous for my liking and I fear for the pilot's life. Surely a pilotless car would be the same great challenge for the engineers without the huge risk to someone's safety?
There just doesn't seem to be any margin for error at that speed.

Martin.

[Ady1Participant @ady1]

There just doesn't seem to be any margin for error at that speed

That's the challenge, they've taken 20 years between Thrust SSC and Bloodhound for another 250mph

Bloodhound will go faster than any passenger plane ever built, only concorde and concordski have gone faster

Reading the comments on the BBC site it looks like most people just don't realise how big a challenge this is

It's going to be a nailbiter

[Ady1Participant @ady1]

They've taken Colin Chapmans advice: "just add lightness"

This new car is 4 tonnes lighter than Thrust SSC

[JAParticipant @ja]

Posted by blowlamp on 16/03/2015 10:00:37:

I don't want to be a killjoy, but this looks too dangerous for my liking and I fear for the pilot's life. Surely a pilotless car would be the same great challenge for the engineers without the huge risk to someone's safety?
There just doesn't seem to be any margin for error at that speed.

Martin.

After the War the government ordered a supersonic development aeroplane from Miles, the M52. Half way through its construction they got cold feet about putting a pilot through the "sound barrier" so they cancelled it and instead messed about with rocket powered models. The result was that we, the British, introduced into service our first true supersonic aircraft (that is in level flight) about eight years after the Americans and six years after the Russians.

The really sad thing is that the M52 would have worked.

JA

[Chris TriceParticipant @christrice43267]

Down force in this car only has to be enough to stop it lifting. Downforce is more usually about having the tyres maintain grip on the tarmac particularly when cornering.

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