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Author Topic: Simspeed UWD LSR Design Project  (Read 17799 times)

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Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #60 on: July 30, 2019, 02:13:20 PM »
I believe that there was a streamliner that had a sort of a pole extending from its nose strait forward so the driver could sight down it and know if things were getting out of shape.

I didn't see it in person but read about it.
Does anyone else remember this?

  Don

Hi Don,
I can see how a pole extended from the nose would offer a indication of change in the straight forward direction.  To me, a yaw string serves the same purpose much more practically applied.  Thanks... Terry

Offline TrickyDicky

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Re: Simspeed UWD LSR Design Project
« Reply #61 on: July 30, 2019, 02:27:56 PM »
How about this one for DIF?

Offline Interested Observer

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Re: Simspeed UWD LSR Design Project
« Reply #62 on: July 30, 2019, 02:49:45 PM »
Quote
1) Changes in airflow direction along the nose that diverge from the intended straight line path are in fact a primary indicator of changes in vehicle/terrain orientation.
  Yeah, until there is a side wind or gust.  You can bet the driver is going to be focused on the far horizon, not some string two feet in front of him.

Quote
2) The A-frames limited by shock absorber travel which in this case is roughly 2" total.
The point was in reference to steering, i.e., rotation about the vertical axis.

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #63 on: July 30, 2019, 03:20:05 PM »
How about this one for DIF?

HA!! I guess roll cages were considered just excess weight back then Tricky.  Notice the 4 wheel drive... Terry

Offline manta22

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Re: Simspeed UWD LSR Design Project
« Reply #64 on: July 30, 2019, 03:37:36 PM »
How about this one for DIF?

That driver is going to be the first to the scene of the accident!

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #65 on: July 30, 2019, 03:39:31 PM »
Quote
1) Changes in airflow direction along the nose that diverge from the intended straight line path are in fact a primary indicator of changes in vehicle/terrain orientation.
  Yeah, until there is a side wind or gust.  You can bet the driver is going to be focused on the far horizon, not some string two feet in front of him.

Quote
2) The A-frames limited by shock absorber travel which in this case is roughly 2" total.
The point was in reference to steering, i.e., rotation about the vertical axis.

I'd agree the string two feet in front of him won't be his point of focus IO; but that doesn't mean its movement to the left or right won't go unnoticed and influence his steering input just as if it were.  What is it about the slow moving far horizon that provides minute influence on a driver's steering decision making do you think?  Would it not seem than a highly sensitive moving instrument directly in the driver's field of vision would more directly influence his judgement even if that wasn't his immediate point of focus?  It would to me so that's my point for why I think it would be effective.

I guess I'm missing your point about the rotational axis IO.  The horizontal pivot point of the tie rod is mounted to the orange steering knuckle.  The two short links running forward from the swivel plates to the crossbar uprights pivot on the vertical axis along the center of the connecting heim joints at the crossbar uprights. To that extent the steering assembly pivots (travels) with the vertical movement of the knuckle.
« Last Edit: July 30, 2019, 03:42:44 PM by Simspeed »

Offline Simspeed

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Re: Simspeed UWD LSR Design Project
« Reply #66 on: July 30, 2019, 03:41:16 PM »
How about this one for DIF?

That driver is going to be the first to the scene of the accident!

Regards, Neil  Tucson, AZ

I'd be interested to know what the outcome of their LSR efforts was.  Did it set a record?  How fast did it go?  Did it crash and burn?  Anyone know?

Offline TD

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Re: Simspeed UWD LSR Design Project
« Reply #67 on: July 30, 2019, 04:22:32 PM »
Quote
I'd be interested to know what the outcome of their LSR efforts was.  Did it set a record?  How fast did it go?  Did it crash and burn?  Anyone know?

Good one TrickyDicky!   See also the first(?) Wingfoot Express.

I'll spare everyone else the bother and tell you that's John Cobb sitting in the Railton Special, later the Railton Mobil Special.

Cobb held the unlimited LSR, briefly, in September 1938 at 353 MPH, then again between August 1939 and September 1947 at 369 MPH.  In September 1947 Cobb raised the record to 394, including one run at 403.  Breedlove, Donald Campbell, and the Summers Brothers went faster, using different means of propulsion, in 1963, 1964, and 1965, respectively.

Surprised no one has mentioned a yaw sensor, such as might be used in any modern production car; perhaps the yaw rates might be higher than one might expect in a production vehicle, making such a sensor unsuitable.  What to do with the output would be the next question.

Thanks for the interesting thread!




Offline TrickyDicky

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Re: Simspeed UWD LSR Design Project
« Reply #68 on: July 30, 2019, 04:37:17 PM »
Quote
I'd be interested to know what the outcome of their LSR efforts was.  Did it set a record?  How fast did it go?  Did it crash and burn?  Anyone know?

Good one TrickyDicky!   See also the first(?) Wingfoot Express.

....

Cobb held the unlimited LSR, briefly, in September 1938 at 353 MPH, then again between August 1939 and September 1947 at 369 MPH.  In September 1947 Cobb raised the record to 394, including one run at 403. 


Yes, first over 400 mph, 13 years before Mickey Thompson.

As far as I know the Railton Special never crashed.

John Cobb died trying to break the World Water Speed Record. Much more dangerous ...

Online Peter Jack

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Re: Simspeed UWD LSR Design Project
« Reply #69 on: July 30, 2019, 04:42:28 PM »
Let's try this one more time. I'm not trying to be obstinate but a driver can't watch a string right outside the windshield and at the same time concentrate on keeping the missile between the flags at great speed. Things are happening too fast! At the same time, don't reject "butt feel" when it comes to car control. By the time you feel yaw in such a forward cockpit you'll already be out of control and way too far gone to correct. The same goes for the string.

Safety has always been a huge thing with any race car I've built or prepared and I'm really proud of the safety record I've maintained. I just can't let this go.

Pete

Offline John Burk

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Re: Simspeed UWD LSR Design Project
« Reply #70 on: July 30, 2019, 04:55:12 PM »
Terry , frontal area may be less important than a person would think . Knowledgeable people have said here that most (80%?) of the drag of streamlined cars is skin friction .

Offline Stan Back

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Re: Simspeed UWD LSR Design Project
« Reply #71 on: July 30, 2019, 05:08:38 PM »
I remember years ago seeing a roadster that had a 1-inch pointed pole about 5 feet long sticking out the crankhole of the radiator shell.  The driver could not see it.  I asked what that was all about. "Just to trip people walking in front of us without watching where they were going."  Probably didn't help stability or driving at all.
Member of the San Berdoo Roadsters -- "California's Most-Exclusive Roadster Club".
Celebrating 67th anniversary of racing on the salt.

Offline 4-barrel Mike

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Re: Simspeed UWD LSR Design Project
« Reply #72 on: July 30, 2019, 05:33:41 PM »
Was it a white SR?

Mike
Mike Kelly - PROUD owner of the V4F that powered the #1931 VGC to a 82.803 mph record in 2008!

Offline Interested Observer

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Re: Simspeed UWD LSR Design Project
« Reply #73 on: July 30, 2019, 06:32:50 PM »
The minimal separation of the Heim joints at the forward end  of the upper A-arm effectively constitute a pivot point that, in conjunction with the Heim on the aft end of the lower A-arm, would allow the ?steering knuckle? to rotate about the connecting axis, likely producing unwanted steering effects and probably a god-awful speed wobble.

Online Peter Jack

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Re: Simspeed UWD LSR Design Project
« Reply #74 on: July 30, 2019, 08:42:07 PM »
Terry:

This continues to be a really interesting thread because there's lots of interesting input being considered in so many different ways. A project such as this needs people who may tend to err on the conservative side and probably always will. There are also the dreamers who come up with the really great ideas which may need at times to be toned down or refined for practical application.

Keep up the good work coordinating this whole thing. We finally have a dreamer who's fun to work with.  :cheers: :cheers: :cheers:

Pete