Author Topic: Bloodhound latest news  (Read 48132 times)

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Offline fordboy628

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Re: Bloodhound latest news
« Reply #60 on: July 14, 2019, 07:06:03 AM »
I have been following the progress of the absolute world land speed record for the past 50 years. I am dumbfounded by the insistence of Thrust 2, Thrust SSC, Bloodhound, and Aussie Invader 5R to eschew pneumatic tires and instead run their vehicles on solid metal wheels.
Since the coefficient of friction of the metal wheels on dry salt lakes, or other hard surfaces, is insufficient to provide steering control they must find semi-soft surfaces to run on. Since these metal wheels obtain steering control by, in effect, machining grooves in the race course surface, they literally destroy the course as they run and cannot return on the exact same path. Also, finding the optimal surface composition for the record course seems to be adding unnecessary complication to the search for the land speed record venues.
When we ran The Blue Flame in 1970 on pneumatic tires, the steering control was excellent as the coefficient of friction approached that of rubber on asphalt or concrete. The Goodyear tires and our wheels were tested at Goodyear at speeds up to 850 mi/h without failure. The only failure in testing occurred when the wheel mounting mandrel broke loose at speed and the tire and wheel spun around in the concrete test cell. The wheel, while not being used afterward, only had some gouges on the rim from impacting the cell walls and still looked nice as a display piece.
Three of the four pneumatic tires and wheels were replaced for minor reasons on the salt flats. When one of the two front tires leaked air (probably the O-ring seal between the wheel center and the outer flange), we replaced both at the same time. One of the rear tires was replaced after a towed braking incident (locked up tire and skidded) wore through most of the thin rubber tread. The fourth tire was used for all 24 timed runs.
Since we could design and build 850 mi/h pneumatic tires 50 years ago, it should be a simple task to design and build 1,000 mi/h tires (and wheels) with the materials and design improvements since that period of time. When I think of all the time wasted by the LSR teams trying to use metal wheels for providing the steering function I am amazed. Just my opinion.

My experience is with the Oregon state highway department pavement research program.  Higher tire internal air pressures do create greater tire contact patch pressures.  It is not often a linear relationship but it is close.  The "tire pressure" in metal wheels is related to the moduli of elasticity which is magnitudes higher than the contact pressure with pneumatic tires.  Solid tires do tear up the racing surface.

It is called "common sense".

But in my experience, it turns out that it is NOT very "common" at all . . . . . . .

YMMV

The ability of other engineers to logically work through difficult engineering problems, seems to me, to have "diminished" over the span of my career.   Now it seems everyone wants to be a "specialist", with no regard for the overall program, or how "their segment" fits into the overall scheme.   You can't "get to the Moon" with that sort of attitude.   And the "moon" you do get . . . .  well, use your imagination . . . . . .  :roll:

 :dhorse:
« Last Edit: July 14, 2019, 07:15:19 AM by fordboy628 »
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Offline MAYOMAN

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Re: Bloodhound latest news
« Reply #61 on: July 14, 2019, 01:37:38 PM »
This section view of The Blue Flame rear wheel and pneumatic tire assembly will give a little better idea of what we did in 1970. The outer wheel flanges were sealed with rubber O-rings. Tire pressure was 350 psi. The tire imprint on the salt surface, with aerodynamic loading at 660 mi/h, was about 2 inches wide as the tire cross section expanded outward from inertia. The impression was barely visible, maybe 1/8 inch or less deep. With computerized solid modeling and analysis available now, the wheel design could have been more aero and less massive. We had planned to re-visit wheel fairings for the planned supersonic attempts in later record attempts. Our schedule for design and construction for 1970 was very tight, so we compromised to meet the less than 2 years' time available.
The road is long - Life is short - Drive fast

Offline wobblywalrus

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Re: Bloodhound latest news
« Reply #62 on: August 02, 2019, 03:00:42 PM »
An article about the upcoming journey to Africa.https://www.bbc.com/news/science-environment-49184375

Offline wobblywalrus

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Re: Bloodhound latest news
« Reply #63 on: September 23, 2019, 01:29:47 AM »
An update on the Bloodhound progress.https://www.bbc.com/news/science-environment-49669929

Offline 4-barrel Mike

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Offline Doc B.

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Re: Bloodhound latest news
« Reply #66 on: October 21, 2019, 04:17:10 PM »
RaceDay has been putting up some live coverage at Hakskeen Pan on their Facebook page.

Offline racefanwfo

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Re: Bloodhound latest news
« Reply #67 on: October 22, 2019, 07:25:45 PM »
So it has been 5 days since bloodhound has been on the pan and they still have not run the car. What are they waiting for.
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Offline wobblywalrus

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Re: Bloodhound latest news
« Reply #68 on: October 22, 2019, 09:18:03 PM »
Go onto the "Science" page on the BBC World News website to find their latest posts.


Offline MAYOMAN

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Re: Bloodhound latest news
« Reply #70 on: October 25, 2019, 04:31:16 PM »
Bloodhound takes first drive across the desert
By Jonathan Amos BBC Science Correspondent
The Bloodhound supersonic car has completed its first drive across the Hakskeen dry lake in South Africa.
Pilot Andy Green took the jet-powered vehicle on a gentle 100mph (160km/h) shakedown test run on Friday.
Bloodhound is in Northern Cape for high-speed trials as it works towards an assault on the land speed record next year.
That mark - of 763mph (1,228km/h) - was set 22 years ago, also by Andy Green, in the Thrust SSC car.
Thrust broke the sound barrier in the process - the first, and only, car to have achieved the feat.
   Bloodhound car arrives in South Africa
   Supersonic car set for high-speed trials
   Relaunch for land speed record car

 Bloodhound will be run at progressively faster and faster speeds in the coming days as engineers seek to verify its design and the proper working of its subsystems.
With a Eurofighter jet engine onboard, it should be capable of reaching 500-600mph (800-965km/h) this year. The addition of a rocket motor in 2020 ought then to take the car over 800mph (1,290km/h).
Engineers will be looking in particular at how much drag Bloodhound is producing in these trials. This will determine the level of thrust they will need from the rocket.
They will also be checking that the parachutes and brakes can bring the car safely to a stop at the end of a high-speed run.
Up to a dozen runs are planned between now and mid November, with the first six taking the speed up in steps of 50mph (80km/h).
The desert floor has been painted to mark out an array of parallel tracks. End to end, these are about 16km (10 miles) long.
The road is long - Life is short - Drive fast

Offline Seldom Seen Slim

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Re: Bloodhound latest news
« Reply #71 on: October 26, 2019, 04:57:37 PM »
Here's a summary of Bloodhound's first run.

https://www.bloodhoundlsr.com/run-report-profile-1/?fbclid=IwAR20j3LP5Foy1nYBMS2inAj78coOsC_mfp4UdWt3ywV8d08v6FcX6EXlyAY



There's nothing like making a few little notes after a run, but geez.  Here's an excerpt from the summary:



Fuel 61% to 14% indicated.  18 min 30 sec run time.

 

    Good start, 52 sec to idle RPM.
    Car rolls at between 55 and 58 NL, on the soft-ish surface at km 5.
    Speed increased in steps, with momentary stops in between. Power stepped up gradually to max dry for final accels.
    Max speed 99 mph.
    Ride is very firm, as expected, with the minor bumps on the track being felt through chassis. Steering is responsive, but not as precise as the Newquay car on tarmac, also as expected.
    Causeway crossed at 50 mph and re-crossed at 75 mph. No major ride disturbance in either direction.
    Comms
        Still difficult with Start Team in high background noise (with AST/EJ200 running).
        First ?Km 4? call from Rescue 1 was unintelligible, Car stopped as a precaution. Repeat call from Rescue 1, and relay from Control, both loud and clear, suggesting one-off corruption of transmission.
    At North end of track, the ?W turn? worked well to turn the Car round and point back down track. Turn radius of the Car is 260-270m.
    Brake pressure gradually increased to 25 Bar with no sign of wheel lock (SKID caption not yet working, pending sensor repair). Small but noticeable decel effect at 25 Bar, as expected.  Max brake temp 250C (against a limit of 500C).  Front bearing temps showed slight increase due to transferred heat.
    Car cooling system working hard with brief temperature warning during final decel, which went out again as the Car stopped.
    90 sec cool down and normal engine shut down.
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Offline Stan Back

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Re: Bloodhound latest news
« Reply #72 on: October 26, 2019, 07:16:31 PM »
Some what familiar to a 350cc MPS/PBG run at SpeedWeek.
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Offline wobblywalrus

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Re: Bloodhound latest news
« Reply #73 on: October 27, 2019, 12:58:03 AM »