Conference terri::cars_uk

    Hi Gavin,
    
    Does it really "drive"? I mean can you go round a roundabout in this
    thing? 
    
    Also, what are the acceleration figures? Will it beat my neighbour's
    XR3i to 60? :-)
                   
    Cheers,
    Barry.

    They've already tested a model bolted on the front end of a rocket
    sledge, and the results are encouraging.
    
    There are also about 5 teams in the race for the record.
    
    I recall that each run will take about 7 miles and last just over 1
    minute -- though this seems a bit short on time.
    
    What I wonder about is the ground effect of the supersonic shock wave. 
    I can't imagine what will happen as it hits the ground and is reflected
    onto the underside of the car, possibly more than once.
    
    There's a call out for volunteers to drive it -- they're expecting
    people will be qualified on fast military jets.

    I expect some of the contributors to note 2266 might be tempted to
    volunteer....
    
    Richard
    

    My father-in-law is designing the active suspension for this car (he
    did the original Lotus active).
    
    The current plan seems to be as the front lifts then the active pushes
    up the back end to maintain a nose down attitude. As you can tell I
    havn't gone into much detail with him.
    
    BTW Richard Noble is not driving but lending his name to the project.
    
    Ian. 

    ILL DRIVE IT....
    

    I think the engines are Rolls-Royce Speys, as in the RAF's Phantoms. 
    The thrust will be awesome, especially if they retain the re-heat.
    
    Re -1  Good luck to your father with the suspension.
    
    As you say, as speed increases the nose will start to lift, especially
    as the shock develops and reflects on the underside.
    
    Then there will be the second reflection coming up under the back. 
    It's conceivable that this'll be enough to make the contact load
    through the wheels _very_ light.
    
    I suppose the answer is to have the engine thrust line set slightly
    nose down, but still can't help thinking of Donald Campbell.  He came
    to grief because the engine thrust line was wrong.

    RE: .8
    
    >>It's conceivable that this'll be enough to make the contact load
    >>through the wheels _very_ light.
      
    Something sticks in the back of my mind about a previous US record
    holder who said that at the speed that they attained the wheels acted
    as gyroscopes and kept the "car" going where they wanted it to go. I
    can't remember if they knew it was going to do this before the went out
    in it. 
    
    Does this sound right?
    
    Dave

    Re. one of the string - Yes Maclaren is one challenger
    
    Re .11
    
    The gyroscopic precession of the road wheels will all be acting in the
    same sense, so the steering will have to be set up to counterbalance
    it.
    
    There will also be precession from the engines.  It won't be enormous
    as the HP and LP compressor and turbine sets contra-rotate.

    
    I think the power output is more like 100,000 bhp.
    
    Saw this on Tomorrow world, where you saw the mini they'd converted to
    rear wheel steer. Very strange!
    
    Steve.
    

    
    I thought the most interesting bit about the 'car' was that it will use
    rear wheel steering  -  that way the frontal section is kept very
    narrow. the set up they were testing (on a mini) had two wheels mounted
    one behind the other. 
    
    Graham  

    Rear wheel steer is very hairy for anything travelling faster than a
    fork-lift.  What you have is the centre of mass ahead of the steering
    wheel.  If you get a swing to, say, the right, then the mass of the
    vehicle is going left, relatively, and trailing the steering wheel
    behind it, tightening the turn.  Lose it like this and you are
    committed to a swiftly tightening spiral that ends in tears.... 
    especially with a narrow-track front end.
    
    Anyone who has done a handbrake turn will have a feel for this.  Most
    times you bang the wheel over and the handbrake is superfluous.
    
    ...But I'm sure there's a rational explanation.  Perhaps the back wheel
    only castors and the steering is done with a rudder - at those sorts of
    speeds, it would be entirely feasible.
    
    Richard
    

    Nope, definately rear wheel steer. Maybe the deliberate offset of the two
    rear tyres will help to alleviate the 'Heyter handling factor'.
    
    Besides, isn't rudder steering banned? I seem to remember that there
    are certain features (steering with wheels being one of them) that must
    be present to classify the vehicle as a car. As opposed to an aeroplane
    that just doesn't bother to take off!
    
    Then again I could be talking a load of ol sump sludge!
    
    Gav.

    Is there a computer handling the steering?  If it was unstable in yaw,
    but with the computer keeping it on line, it could have very quick
    steering for very little wheel movement.
    
    And it could do all the test runs unmanned, on the tape so to speak,
    and just put a "chimp" in for the qualifying run...
    
    Richard
    

    re .0 
    I would too, no hesitation. It's neither more difficult then the IOM
    TT, nor more dangerous than my daily commuting so....
    
    Peter

    Although not a regular NOTES user, this is one that I can't resist. The
    reason is that apart from being a Digital employee, I'm also part of
    Richard Noble's newly announced Thrust SSC Team.
    
    I hope the following answers some of the questions raised so far. If
    not, then there is an official team supporters club that gives you an
    opportunity to find out more by meeting team members, visiting the
    place where the car is being built and getting regular project
    bulletins and quarterly newsletters. Write to: Mach 1 Club, PO Box 77,
    Twickenham, Middx, TW12 2XN.
    
    The car was conceived by Ron Ayers, ex head of missile research at
    British Aerospace, along with Richard Noble himself and Glynne Bowsher,
    a team member from Thrust 2 days who works for Lucas Aerospace.
    Basically, Ron did everything outside, while Glynne did everything
    inside. The car is a combination of tubular steel spaceframe and carbon
    composites, 55 feet long and weighs a touch over 7 tons. The
    computer model predicts performance of 0 - 850+ - 0 in just over 70
    seconds, taking most of the 13 miles of available track at Black Rock,
    Nevada. Should be quite a tap up the kidneys!!
       
    Power to travel at supersonic speeds is not a problem, keeping it safe
    and stable is. Ron's initial work was developed using computational
    fluid dynamics, the results suggesting that the design would work and
    would not fly. Ideally, this needed checking in a supersonic rolling
    road wind tunnel - none exist. Even F1 tunnels only work at about
    100mph, the results being extrapolated for 200+mph. Doing this for
    speeds up to 1,000mph would be daft.
    
    The answer was the government's missile proving test track at Pendine. A
    model of the car was mounted on a rocket sled with wheels attached to
    the outside of the tracks so that the space between could be filled in
    to simulate a desert surface. Sensors all over the car and cameras
    every 100metres running at 100,000 frames per second recorded what went
    on. It went from zero to Mach 1.2 in 0.8 of a sec!! The whole thing was
    repeated six times to verify the results which were then compared with
    the CFD output. As a result, the team now knows exactly what happens
    under a car in excess of Mach 1. Even McLaren haven't done that.
    
    The problem is not the expected shock wave per se, but the strange
    things that happen when air flow over and under different parts of the
    car moves from sub-sonic to transonic to supersonic at different rates
    and begins to interfere with each other. The active suspension system
    mentioned is designed to keep the car absolutely level - Ron says that
    pitch up by one quarter of one degree would lead to a back flip - not
    recommended!
    
    The overall layout is designed to be as stable as possible. One big
    engine would be ideal in order to reduce cross sectional area but that
    means the driver sitting to one side or out in front. By choosing two
    engines, there is sufficient thrust to go supersonic and overcome the
    necessary drag needed to make the thing stable. It also means the
    driver sits in the safest place in the car surrounded by a very strong
    structure.
    
    The engines are placed forward to get the centre of gravity up front,
    while the long fuselage has a highly swept tailplane assemply at the
    rear to induce aerodynamic drag. It's the same principle as a dart - CG
    up front, drag at rear. The wheels are mounted on the outside of each
    engine pod to give the widest possible track and have to be fixed in
    order to keep cross sectional area to the minimum.
    
    Contrary to popular belief, rear wheel steering is far more precise
    than front wheel steering, exactly what you need for an LSR car that
    doesn't need to go around corners. It just happens that those needing
    this precision (forklifts, harvesters etc) are also slow moving, hence
    the myth that front-wheel steering is needed. By the way, the rules
    state that two wheels must be steerable, although aerodynamic aids can
    also be used.
    
    Finally, the engines. They are Rolls-Royce Speys, but not even the
    hotted up versions used in the Phantom. RR developed a super tough
    version called the 205 but only ever built 12 of them. The team has
    two, plus two cooking 203s for testing. Combined thrust is over
    50,000lbs, or the equivalent of 100,000hp. The build program will be
    complete by this time next year, with first runs at Black Rock in
    September.
    
    Watch out for a big (!) display at the Motor Show later this year.
    
    
    
    Robin Richardson
    
                                     

    Interesting stuff!
    
    Is there any truth in the story that Digital, maker's of the world's
    fastest chip, were approached and refused an offer to sponsor this
    effort?
    
    Laurie.

    I've no argument about the precision of rear wheel steer, just its
    stability.  Most aircraft have nosewheels nowadays because it's so much
    easier to keep them tracking straight on landing.  Any fule can land a
    nosewheel aeroplane.  The taildragger is a different story...
    
    Does the tail go a long way back behind the rear wheels? ie using
    aerodynamics to keep it straight?
    
    Richard
    

    Excellent,
    
    Thanks to Robin for clearing up those things. I hope we can encourage
    you to keep us posted of any significant developments.
    
    Good luck to the team,
    Gavin.

    >I've no argument about the precision of rear wheel steer, just its
    >stability.  Most aircraft have nosewheels nowadays because it's so much
    >easier to keep them tracking straight on landing.  Any fule can land a
    >nosewheel aeroplane.  The taildragger is a different story...
    
    I would have thought that in the aircraft case, the tail wheel does not
    have enough weight on it to develop decent steering force, and the
    rudder is too small to be of use once the craft is well into its
    landing run. Also there is the weight transfer as the craft is
    decelerating.
    
    PHil

    Yes, that's part of the problem.  If you get too much weight transfer
    in the vertical plane (sic), the front of the plane hits the deck.  If
    the weight gets off-centre sideways, say to the left, the main wheels
    are bearing right while the mass of the vehicle is still mostly going
    straight forward with scarcely diminished speed.  This tends to tighten
    the turn to the right.  In cars, you swap ends at this point. 
    Aeroplanes, usually with a higher centre of mass, topple, bash the left
    wing into the ground and end up on their backs in extreme cases.  This
    is why most aircraft nowadays are nose-draggers.  The steering may not
    be as precise or as quick, but it's stable.  If you get out of line, it
    doesn't conspire to make a swerve out of a wobble.
    
    The team probably need to work up a clear explanation of how this works
    if they want to get pilots volunteering to taxy a taildragger at Mach 1
    
    
    Richard
    

    Having flown *many* miles in a DC-3 (also known during WWII as a
    Dakota) I can confidently state that a taildragger does *not* have to
    be landed on all three wheels at the same time.  The DC-3 lands main
    gear first and the tail settles as speed drops.  Some DC-3's even had
    main gear that could be rotated so that the body and wings could face
    into a quartering wind while the wheels went straight down the landing
    strip.  No problem at all with stability even in the strangest of
    situations.
    
    Brian Pituley
    

    Thanks for the message Brian. Truly interesting to hear from a REAL
    pilot   8^))
    
    My comment on doing 3 point landings comes from my sailplane experience
    of outfield landings. You always want to achieve the most precise
    landing possible, no extra speed, as the fields are sometimes a bit
    short. Landing on an aerodrome is a different matter, and I also did
    main gear landings to please the US FAA people who hate to see 3 point
    landings (other safety reasons I can understand).
    
    Please tell us more about your Dakota experience !

    Ahhhh Daks..... (muse muse)
    
    Spent my formative years in colonial climes flying around in Dakotas,
    Viscounts and Britannias. Even remember a flight in a comet (round
    windows of course). But enough of this digression and back to the
    basenote subject.
    
    When is the record attempt scheduled to take place?
    
    Gav.

    Re the question, were Digital approached to help the project - the
    answer is yes. We needed a small number of PCs, printers and the
    necessary software to take CAD data generated on an IBM mainframe and
    give it to the three or four sub-contractors handling the build
    programme. Since the kit was needed only on loan for the duration of
    the project and knowing the media interest that this would generate, I
    obviously wanted to see Digital involved, although there was never any
    question of asking for sponsorship. Sadly, the answer was no, which I
    guess is understandable given the situation at the moment.
    
    Not suprisingly, there were a number of other vendors interested enough
    to come up with the hardware and software free of charge in return for
    using project involvement in their marketing campaigns at some point in
    the future.
    
    To return to the car itself and another question asked, it will be
    complete this time next year and shipped to the USA to run in Sept-Oct
    at Black Rock. We went out last for a ten year anniversary bash to
    celebrate Thrust 2's continuing tenure of the record and to check out
    desert conditions again. They're even better than in 1984. We also met
    up with Craig Breedlove and his team, who have held the record five
    times in the past and are unveiling their own challenger in Detroit in
    early July. They hope to run later this year.
    
    Also in the hunt are two other US teams, Art Arfons with a super small
    and lightweight jet car, and the Kikes/Shockley/Swenson J-79 powered
    jet car, which is not small. While Breedlove is also targetting Mach 1,
    the other two would be content just to get Richard's record. 
    
    Over (under?) in Australia, Rosco McGlashan is running a Thrust2
    lookalike car with less power but smaller cross-sectional area, and on
    a much harder surface - Lake Gairdner. Rain stopped play when he had
    worked up to about 500mph but again he will be lucky to exceed 633.468
    - the current record. Incidentally, he's being helped out by John
    Ackroyd who designed Thrust 2 and the various capsules used by Branson
    and Lindstrom in the trans Atlantic and Pacific Balloons. John took me
    to Stead Field in Reno last year for a squint at his lastest baby, a
    three man capsule with twin balloons - one helium, one hot air, -
    designed to travel non-stop around the world. Three attempts, three
    failures, but the work goes on until they get it right.
    
    On the question of steering via aerodynamic aids, this has been tried
    in the past without success, In '61 Breedlove ran a fixed wheel jet car
    steered by a rudder mounted under the nose. It went everyway except
    straight until he introduced only 1 degree of steering to the front
    wheel. It then went all the way to 526. At the same time, Nathan Ostich
    ran another jet car with steering but found that any movement in excess
    of 1 degree was hopeless because the wheels just slid around on the
    hard salt of Bonneville. He added fins and a rudder before getting it under
    control. Interestingly, McGlashan is having the same problems with his
    car in Oz. Thrust SSC will use wheels designed to plane across the
    desert surface (much like an unlimited hydroplane on water) and will
    have 6 degrees of steering movement.
    
    Some alternatives suggested by others for the future include use of a
    vectored nozzle jet engine being developed by Pratt & Whitney connected
    to a fly by wire steering system, or if you really want to cheat, a
    laser guidance system as used on smart bombs. 
    
    
    Robin Richardson
    
    Understandably,

>>>    Having flown *many* miles in a DC-3 (also known during WWII as a
>>>    Dakota)
       ^^^^^^

	Didn't the Americans have a more affectionate term for them - the
Goonibird?

				Malcolm who couldn't possibly remember WWII!