Author Topic: Rear brakes inside the body of a thrust-powered streamliner  (Read 766 times)

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Offline tallguy

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Rear brakes inside the body of a thrust-powered streamliner
« on: November 07, 2023, 11:16:35 PM »
Hi, all.

I've seen many photos of exposed rear wheels of thrust-powered cars -- such as the North American Eagle, Aussie Invader 5R,
and the Blue Flame. 

It's pretty well-known that an exposed rear wheel, out in the wind and unfaired, isn't very aerodynamic; a disk brake assembly, out in the wind like that, would also create a lot of drag force. 

I'm certainly not suggesting that the rear wheels should not have brakes . . . but why can't the brake disks be "inboard" (contained within the streamlined body) and attached to the axles -- which do extend pretty far from the body in order to provide a decent amount of track (width) for stability of the vehicle?

Each axle could be independently mounted in bearings and suspension (if desired), so the calipers and other associated hardware wouldn't have to be in the wind.  The rear wheels could be faired, and so could the axles.  Because a round axle, out in the wind, isn't all that aerodynamic, it could be surrounded by an airfoil-shaped structure that could provide not only mechanical support, but also hold an "outboard" bearing to support the axle, very close to the wheel, several feet away from the main fuselage of the car. 

I'd love to see feedback about this, preferably from someone with experience on a team that has run a car like this . . . even
if it's not thrust-powered.  What I'm most interested in addressing here is aerodynamics.
« Last Edit: November 08, 2023, 12:36:57 AM by tallguy »

Offline Stainless1

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #1 on: November 08, 2023, 10:20:30 AM »
Hey Tall... Thrust powered vehicles don't have axels.... they have spindles...  :roll:  :cheers:
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Offline salt27

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #2 on: November 08, 2023, 02:21:53 PM »
Go to "Discussions on absolute land speed records"
        "The Blue Flame's 50th Anniversary"
       Reply #106.

Interesting information from someone with experience.

  Don

Offline MAYOMAN

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #3 on: November 08, 2023, 04:40:12 PM »
The original design of The Blue Flame had rear wheel fairings and the strut attachments streamlined in an air-foil shaped structure. In the transonic wind tunnel that design resulted in unstable pitching of the vehicle in the transonic speed range. With the need for a quick solution, the open wheel and struts was tested and found more stable even though the drag coefficient was increased. It was thought we could test a better solution at a later date, but that never happened. I have better illustrations, but too large for this site.
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Offline stay`tee

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #4 on: November 08, 2023, 08:17:21 PM »
The original design of The Blue Flame had rear wheel fairings and the strut attachments streamlined in an air-foil shaped structure. In the transonic wind tunnel that design resulted in unstable pitching of the vehicle in the transonic speed range. With the need for a quick solution, the open wheel and struts was tested and found more stable even though the drag coefficient was increased. It was thought we could test a better solution at a later date, but that never happened. I have better illustrations, but too large for this site.

yes, resistance can be your friend, even on regular vehicles   :wink:
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Offline tortoise

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #5 on: November 08, 2023, 08:46:25 PM »
The original design of The Blue Flame had rear wheel fairings and the strut attachments streamlined in an air-foil shaped structure. In the transonic wind tunnel that design resulted in unstable pitching of the vehicle in the transonic speed range. With the need for a quick solution, the open wheel and struts was tested and found more stable even though the drag coefficient was increased. It was thought we could test a better solution at a later date, but that never happened. I have better illustrations, but too large for this site.
Have you ever seen or evaluated the plans for the once-proposed rocket version of the Carbiliner? It had faired rear wheels.

Offline tallguy

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #6 on: March 14, 2024, 03:07:54 AM »
Hey Tall... Thrust powered vehicles don't have axels.... they have spindles...  :roll:  :cheers:

I appreciate your posting.  If the wheel is rigidly attached to a rotating shaft, upon which a disk brake rotor ((contained
within the body/skin of the vehicle -- for aerodynamic purposes -- is attached)), would this shaft not be an axle?
« Last Edit: March 14, 2024, 03:09:45 AM by tallguy »

Offline slowalex

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #7 on: March 14, 2024, 08:39:29 AM »
Inboard disk brakes used to be quite popular in sports and racing cars the 1970s, mostly to reduce unsprung weight.

I did a couple of circuit races about 20 years ago in an Alfa Romeo Alfasud, which was FWD with inboard disk brakes on the front and managed to find some nice Ferodo race pads with high coefficient of friction and some competition brake fluid that could handle high temperatures. This worked very well except the pad wear rate was still quite high, so I thought the next step might be larger pads, 4 pot callipers and perhaps even larger diameter and ventilated inboard disks.

I shared these thoughts with someone with a bit more experience racing these cars than myself and he told me someone already tried all those things and he ended up snapping an axle during braking. He was lucky not to do serious damage to himself and the car. Most of those cars were quite light maybe 800 or 900 kg, but there was enough braking force to snap an axle.

Might need some strong axles (spindles or whatever you call them) on a streamliner with inboard disk brakes.

Offline aircap

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #8 on: March 14, 2024, 11:37:53 PM »
I've heard many salt racers say they only used brakes when loading and unloading the trailer.
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Offline Stan Back

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #9 on: March 15, 2024, 12:23:25 PM »
For us "little guys" with 200+ MPH Roadsters, we always used the winch when loading and unloading the trailer.  And with 200+ runs, we used the rear (only) brakes -- as long as you got off by the 6, there's no problems and you don't have to clean and repack the chute.

"Different strokes for different folks."
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Offline kiwi belly tank

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Re: Rear brakes inside the body of a thrust-powered streamliner
« Reply #10 on: March 15, 2024, 04:28:27 PM »
 Stopping is the most important part of any high speed run but braking is limited to the amount of traction & that is minimal on a loose surface like salt. I have 4 wheel one ton dually brakes in my liner with steel brake rotors & they are set up for water cooling. Since it's 4WD with no center differential in the transfer case & Torsen carriers on both ends it can't lock up any single wheel without having something in the driveline break. It has 6 chute tubes & engine braking all the way back to 1st gear.
I don't think it's possible to overkill safety or braking & certainly now that the salt is getting shorter.
 Al had a high speed chute fail one time in the high 300's & had to smoke the two wheel brakes to slow down enough to deploy the low speed, it wasn't pretty!
 Nolan lost all his chutes & fried the rear brakes trying to stop on that last run that killed him. I know that because I could smell them after he went by.
 That's somewhere I don't want to be!
  Sid.