Author Topic: Bockscar 2.0  (Read 71157 times)

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Offline Sumner

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Re: Bockscar 2.0
« Reply #360 on: November 01, 2018, 10:15:05 AM »
...Tom Burkland .... is not a flat bottom car fan....

I tend to agree with that except if you keep the air from going under the car such as Speed Demon has done.  Not sure just rounding up the tail will help as far as getting away from the 'flat bottom'.  I like Rex's suggestion and is very similar to what I've done.  Good way to increase the CP.  

If mine was ever to be done it will have a rounded bottom front to rear, where the lowest part is 6 inches from the ground, helping to keeping air from being compressed under the car.  Stole some of that from one of the solar racers in the following book that has a smaller solar array and employs a better aero package to make up for it ...



https://www.amazon.com/Leading-Edge-Engineering-Performance/dp/0837608600/ref=sr_1_1?ie=UTF8&qid=1541084965&sr=8-1&keywords=The+Leading+Edge

A lot of the book was over my head but the conclusions were something that could be worked from.

Impressed with the progress you are making  :cheers:,

Sum
« Last Edit: November 01, 2018, 10:17:24 AM by Sumner »

Offline tauruck

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Re: Bockscar 2.0
« Reply #361 on: November 01, 2018, 11:12:35 AM »
Skirts!!!!!. Betcha everyone here loves skirts!. :-D :cheers: :cheers: :cheers:

Offline Stainless1

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Re: Bockscar 2.0
« Reply #362 on: November 01, 2018, 11:18:14 AM »
Midget, the original K liner had 2 motors, the lakester conversion hid a Honda 750 Interceptor motorcycle inside... with the triple tree and upper frame cut off, the rear axle ran on pillow blocks attached to the motorcycle swingarm.  It had motors from Honda, Kawasaki and Suzuki, 45 to 99.5 CI in it...

Sum, We try to limit the amount of air going under and give the air under a place to go.  Nose down, tail up

Mike.... only short ones  :roll:  :wink:

We had a lot of fun with that car...  :cheers:
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline Stainless1

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Re: Bockscar 2.0
« Reply #363 on: November 01, 2018, 11:59:30 AM »
No, I'm not too good with photo edit, but I think this is what Rex is suggesting and it would be a lot easier than duplicating the original...
Still need to talk to a couple of aero folks.
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline Lemming Motors

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Re: Bockscar 2.0
« Reply #364 on: November 01, 2018, 12:28:07 PM »
That was very good editing! I have read the thread and could see both photos and it still took several times back and forth to see the difference. I like the look of the edited version but function is more important so it will be interesting to see what results.
A Bonneville Lakester please barman.
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Offline Sumner

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Re: Bockscar 2.0
« Reply #365 on: November 01, 2018, 12:33:26 PM »

Sum, We try to limit the amount of air going under and give the air under a place to go.  Nose down, tail up

The 'Porkpie' influence and a good one.....

Also like the 'Rex' idea to go with it..
Sum

Offline PorkPie

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Re: Bockscar 2.0
« Reply #366 on: November 01, 2018, 05:13:35 PM »
.....really........
[/quote]

The 'Porkpie' influence and a good one.....

Sum

[/quote]
Pork Pie

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Offline Milwaukee Midget

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Re: Bockscar 2.0
« Reply #367 on: November 02, 2018, 08:07:20 AM »

The 'Porkpie' influence and a good one.....


Best in the business.  :cheers:
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!

Offline Stainless1

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Re: Bockscar 2.0
« Reply #368 on: November 03, 2018, 11:26:21 AM »
Well it looks like the up swoop will stay... the narrow rear track requires a place for the turbulent air between the wheels to go.  A wide track rear and the change makes sense.... and if I get a chance at the wind tunnel that will be one of the things I check for improvements. 
I wanted to wind tunnel the old car, and was planning that during the 2017 racing season... unfortunately the car did not survive SpeedWeek
I should hear back from my Chute tube material quote Monday.... Looking at 5.5 or 5.75 x .065 or .083 304 stainless for the tube.  If it comes in too expensive I guess I hit plan B and try to roll and weld a tube.  Yep the old tube was bent and dented in the crash... already thought about reusing it  :|
Sometimes I wish I was rich instead of good looking...   :roll: :cheers:
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline Rex Schimmer

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Re: Bockscar 2.0
« Reply #369 on: November 03, 2018, 05:20:42 PM »
Stainless,
In all of the many configurations that you have ran the old car in did you ever run the rear tires in a wide track configuration? I am thinking 10-12 inches between the body and the tires.  I cannot see the logic of running the tires close to the body as in my thinking they interfere with what we hope is the smooth and attached air as it flows down the side of the car. I have seen on many cars, specifically lakesters, that run the tires close to the body, an arch of salt build up on the body just in front of the rear tires. It is most prominent on flat sided cars, like the your car but I have also seen it on round section cars where the body comes close to the tire, such as Seth Hammon's car. Pretty good indication of the air being turbulent and un-attached. This makes any type of converging rear body work almost a waste of time.

Rex
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Offline Stainless1

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Re: Bockscar 2.0
« Reply #370 on: November 04, 2018, 06:02:05 PM »
Rex, the original streamliner was designed by Lynn Yakel, when we refitted it to a lakester Lynn gave us front axle position on the body and track, and rear axle position and track.  He specified the narrow rear track for the car, so that is what we did.  It has never had a wide rear track. 
I guess when it is no longer competitive or I get some tunnel time I can investigate using a wide track in the rear... and fairings for the axles.  Some of the other things I thought about are being incorporated due to roll cage size, and the way I'm building it.
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline tortoise

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Re: Bockscar 2.0
« Reply #371 on: November 04, 2018, 06:59:32 PM »
I cannot see the logic of running the tires close to the body as in my thinking they interfere with what we hope is the smooth and attached air as it flows down the side of the car.

"Logic" won't answer this question. Maybe putting the tires right up close to the body prevents them from generating a big turbulent wake on the side near the body. Maybe the tires would be partially in a slower moving boundary layer. Maybe tire drag is a bigger thing than body drag. Maybe.

Offline Lemming Motors

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Re: Bockscar 2.0
« Reply #372 on: November 05, 2018, 07:41:22 AM »
When I started thinking about building a Lakester in the UK and was perusing the Bonneville results I kept coming across something called Bockscar. I admit to a small amount of awe but really struggled to find many pictures in the public domain so was thrilled to see it in the flesh in 2017 (albeit on its last start line).

Clearly whatever Bockscar was doing was right for Bockscar - I am pursuing a different design thingy (philosophy is too strong a word), obviously in the hope that it will be righter  :-D

Wheels out in the breeze are the big (Lakester) aero drag component and to my mind the influence of wheel wake on the streamlined body (wide track vs. narrow) is probably 'the' question of our time (for Lakesters) but is probably entirely dependant on the body shape - curved floor or sides, ground clearance, rear overhang etc. I gather there is limited data.

Is the narrow track design more about an 'enclosed' frontal area I wonder.

I assume F1 have car bodies in plan inspired by an iconic beverage bottle to give the wake somewhere to go (that they can then control to diffusers, wings etc.)
A Bonneville Lakester please barman.
Certainly sir; a lick of salt, a sip of gas and a twist of Lemming. More Lemming sir?
Just a squeeze.

A Squeeze of Lemming it is sir.

Offline ggl205

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Re: Bockscar 2.0
« Reply #373 on: November 05, 2018, 08:07:56 AM »
I was always a proponent of very narrow track, both front and rear. My first lakester was such a car and was very long and very angular. By most accounts, that car should not have gone as fast as it did. Today, my better idea for the second car may or may not prove faster but one thing the wind tunnel did hint at was wider front track. As rear suspension is stock Reynard Formula Continental, track is wide at 55". Front track has been widened to 50" so I will have to wait until next year to see if these changes (and many others), improve speed. 

Rex, I posted a short YouTube video of my car in the Darko wind tunnel and you can clearly see smoke trails of turbulent air coming off front wheels all the way back. So, all that nastiness from the front stays with you for the entire length of the car. Many years ago, I investigated barge boards in an attempt to deflect front wheel wakes so they do not affect aero the entire length of the body. I still think these have merit but now that I have changed front track, I have no idea where to place them.

John   

Offline Rex Schimmer

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Re: Bockscar 2.0
« Reply #374 on: November 05, 2018, 01:50:06 PM »
John,
Thanks for the vid of your car in the wind tunnel! Pretty informative. The link to the vid is: https://www.youtube.com/watch?v=kPPkEQ3wOos

Several things are of interest to me in this vid: 1. How well the Moon disc work, the air flow around the front tires is very informative. 2. How the disruption of the front wheels carries down the side of the car pretty much making all of the air turbulent and un-attached. 3. The transition from the body to your tail mach-up at some points appears to not re-attach, i.e. high drag. If you do made your rear body in this configuration you should probably use some sort of vortex generator to get the air to attach to your rear body. 4. Attention to detail around places where things protrude from the main body. Really important to address these, especially any toward the front of the car as any turbulence generated by them will disrupt air flow towards the rear of the car.

Duke and I do have in our future plans a trip to the wind tunnel but this year it is the motor on a good dyno is the target. I am also planning to do several detail aero improvements around both the front wheels/axle and improve my rear axle fairing also.

Back to the Bockscar build!

Rex 
Rex

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