RE: 1968 Challenger II sets piston-driven speed record
Discussion
re33 said:
timrud said:
Digi dash is looking well for 50 years old 
You took time to write that but not actually read any information? Check out http://thompsonlsr.com/about/ . The engines aren't original either. I don't understand why that would be a problem? Great project and great achievement.
Looked like a handful, literally.
only1ian said:
Am i right to think he’s constantly correcting the torque from a clockwise turning pro shaft. That’s why he’s predominantly making left inputs
That's the underlying issue. Engines producing sensible amounts of power will produce enough torque to lift the left side of the car - it's one reason that non centre-driven cars are LHD, as the driver's used as ballast. In centre driven cars (land speed cars, Funny Cars, Fuel Altereds) it's a bit more hairy as your ballast is used up keeping the front end down in general rather than focusing on one corner. With adjustable spindles you can screw the left front down by essentially reducing the static ride height, but that's a trick used more in drag racing than land speed cars.
The salt's quite bumpy - so that compounded with the speed involved make it quite a bumpy ride. For me the most impressive thing was the origins of the car - fundamentally little had changed from the original. Mickey T was a genius way back when, and to be setting records with a car originally built that long ago, is a testament to his design knowledge at the time.
legless said:
Would the fact that one of the engines is mounted backwards mean that the forces balance each other out?
In its current guise, there's an element of the drivetrain overall being in some sort of equilibrium - something the original didn't have as I think the front engine produced less power than the rear (the two now being identical on the output front - so one counteracts the other in regard to twisting the chassis clockwise).It's a very clever packaging exercise, as elephant motors take up a lot of room:
oilit said:
yikes
kudos as you'd never get me doing that ... looks down between legs and realises there are no balls
Yep, from what speed would a roll in that vehicle be dead-cert fatal? Probably a third of its maximum speed? kudos as you'd never get me doing that ... looks down between legs and realises there are no balls
Cocooned between two giant powertrains in a 1960s tubular aluminium clad chassis? No thanks.
Mark-C said:
Is this also the driven wheel record?
I get what the jet engined stuff does in terms of raw speed but it means nothing to me because it just doesn’t feel like it’s a car ...
Piston engined wheel driven record I think.I get what the jet engined stuff does in terms of raw speed but it means nothing to me because it just doesn’t feel like it’s a car ...
The Vesco Turbinator 2 is a turboshaft engined car which went quicker yesterday, 463mph average over a mile with a 470mph exit speed but it’s not official yet as it needs to be backed up today.
HustleRussell said:
Yep, from what speed would a roll in that vehicle be dead-cert fatal? Probably a third of its maximum speed?
Cocooned between two giant powertrains in a 1960s tubular aluminium clad chassis? No thanks.
They're relatively safe these days - I thought Challenger 2 had most of the safety cell swapped out for moly tubing and a titanium cage shield as per what we use in Funny Car racing. Way back when, when pioneers on the salt realised that aero was everything, they started building cars with the crash helmet built into the roll cage to slim the body profile down. Those were the days Cocooned between two giant powertrains in a 1960s tubular aluminium clad chassis? No thanks.
Chris944 said:
It was, for me, a boring video. Okay, the steering inputs looked interesting but nothing else was, with no view through the windscreen or impression of speed.
RM said:
Chris944 said:
with no view through the windscreen
There's a great image on the website.a) the camera was unintentionally tilted downward -- omitting the forward view -- when Thompson settled into the cockpit or
b) a single camera cannot record both forward view and steering inputs -- due to extreme brightness of the salt flats and the subsequent contrast in brightness between a through-the-windscreen view and a view of steering inputs in the cockpit
when you're doing a world-class run of this sort, IMO you want a bit of redundancy -- such as a second camera
could this conjecture be wrong? sure can; but other things say that it might be correct
the website and news releases, for example, use only US Customary Units of measurement: despite the global news value of this event, metric units are omitted
there is nevertheless a profound sense of humanity woven throughout this effort; there are numerous examples; one of these is the "Visiting Policy" stated on the website right next to Thompson's home address in Colorado:
"We're excited to host gearheads, racers, and all of their bored relatives at our Colorado location between 12:00-13:30 Monday through Saturday. Please email Danny 24 hours beforehand so that we know to expect you and can confirm that we're available."
Often the camera placement is deliberate, not to show the velocity involved (for the outside world's benefit); there's a few streamliner vids on YouTube that show the speed a bit more obviously, and interestingly - deviation from the guideline. The team most likely use it for data acquisition purposes - while there'll be a Racepak data recorder onboard measuring all manner of things (including steering input), having a video of the driver's inputs on a run is handy for tuning purposes, or just to see how hairy a run was at the time.
It was noted above, the steering lock involved - it's common to be on full lock, and the ratios involved are such that it's not like steering a circuit car - but they do move around quite a bit. With the speed involved, when you deviate from the guidelines, you could quickly find yourself lost - the terrain all looks the same and you cant tell which way the track goes.
LSR is something I find quite fascinating, and retired drag racers often migrate to it - so my interest is something akin to retirement planning I suppose
It was noted above, the steering lock involved - it's common to be on full lock, and the ratios involved are such that it's not like steering a circuit car - but they do move around quite a bit. With the speed involved, when you deviate from the guidelines, you could quickly find yourself lost - the terrain all looks the same and you cant tell which way the track goes.
LSR is something I find quite fascinating, and retired drag racers often migrate to it - so my interest is something akin to retirement planning I suppose
NFC 85 Vette said:
HustleRussell said:
Yep, from what speed would a roll in that vehicle be dead-cert fatal? Probably a third of its maximum speed?
Cocooned between two giant powertrains in a 1960s tubular aluminium clad chassis? No thanks.
They're relatively safe these days - I thought Challenger 2 had most of the safety cell swapped out for moly tubing and a titanium cage shield as per what we use in Funny Car racing. Way back when, when pioneers on the salt realised that aero was everything, they started building cars with the crash helmet built into the roll cage to slim the body profile down. Those were the days Cocooned between two giant powertrains in a 1960s tubular aluminium clad chassis? No thanks.
Robmarriott said:
Mark-C said:
Is this also the driven wheel record?
I get what the jet engined stuff does in terms of raw speed but it means nothing to me because it just doesn’t feel like it’s a car ...
Piston engined wheel driven record I think.I get what the jet engined stuff does in terms of raw speed but it means nothing to me because it just doesn’t feel like it’s a car ...
The Vesco Turbinator 2 is a turboshaft engined car which went quicker yesterday, 463mph average over a mile with a 470mph exit speed but it’s not official yet as it needs to be backed up today.
unsprung said:
any through-the-windscreen video certainly could be interesting
I wrote to Danny and asked about this; here is his response:
Yes we will post it soon.
Thanks
DT
Challenger II onboard, 2017I wrote to Danny and asked about this; here is his response:
Yes we will post it soon.
Thanks
DT
This was from last year I think - same car, a touch slower than this week's runs; narrowly avoiding mile markers and such at 400mph+. Top notch driving job
There are a bunch of videos on the Youtube channel https://www.youtube.com/user/thompsonlsr/videos
I like these:
I like these:
- 2018 window cam: https://www.youtube.com/watch?v=p3WSYRyY2sI
- 2017 external tracking shot: https://www.youtube.com/watch?v=bhCQQDHHOfA
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