Author Topic: Australian Belly Tank  (Read 3171224 times)

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Offline Rex Schimmer

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Re: Australian Belly Tank
« Reply #4140 on: December 22, 2013, 02:26:18 PM »
Looking at your concept drawings of the conversion to a streamliner reminded me of Bob Herda's liner from the 60-70's, and it has a tail fin! Bob ran as high as the 340 mph range before his tragic death. Another thought would be doing something like the Frank Lockhart car which is really just a lakester with wheel covers. This car was calculated to be able to go over 300 with the supercharged V16 Miller engine it had. Tires were the problem and what eventually caused the accident that killed Lockhart. One of the things that probably would need to not be copied from the Lockhart car would be the front wheel covers turned with the wheels, I would think this could be a problem over 200. Probably best to make them wide enough to be able to turn the front wheels inside them. Just some thoughts. Pics attached.

BTW if you want to see lots of pics of streamliners go to: https://www.google.com/search?q=bonneville+streamliner&rlz=1C1GGGE_enUS387US391&espv=210&es_sm=122&tbm=isch&tbo=u&source=univ&sa=X&ei=HDa3UqXmCdLzoATy14CwCg&ved

Lots of neat pics of many liners new and old and lots of insperation.

Rex
Rex

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Offline Reverend Hedgash

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Re: Australian Belly Tank
« Reply #4141 on: December 23, 2013, 06:52:37 AM »
....I am still intrigued by the double fin behind the wheels as you say....

The only advantage I'd see with two vertical stabilizers would be if there was a wing between them for your added downforce.  Otherwise there is more aero penalty to be accrued with no real gain in center of pressure with two over one.  A vertical stabilizer is going to have more effect on CP than a canted one.  Then again you would need two along with their added drag.  Saying that properly designed verticals and a wing for downforce don't necessarily need to add a lot of drag.  They both can have Cd's down under .1 and very little frontal area.

On Hooley's Stude we have added no weight behind the axle and considerable weight ahead of it but then also more weight further ahead to keep the CG forward.  So you end up with a lot of weight that is doing nothing for traction but still needed for safety.

I guess I missed it but are you converting the tank to a streamliner or is this a whole new car?  Also you coming this way at all?  We'd love to see you.  Ruth said to say hi to you guys, me to  :-),

Sum



Hey Sum great to hear from you, its been a while.

The idea is simply a different body to the car so we can be in streamline class. We will still run both bodies and improve both as we go.
the issue for me is I am out of the game a bit, firstly living in the UK means I cannot do the weekend assists on the build and as it is mostly mechanical that is Dr G and the Colonel's forte not mine. So I want something new to design and play with!  I expect it to take awhile to get right but if you keep chipping away and surround yourself with smart people and ask a lot of questions (hence here) we should see progress and one day hopefully have something on the car.

Your comments as always are spot on. You might be back on the scene but certainly not slow! I am very keen to use an under body ground effects system with a diffuser at the back to assist it in downforce for minimum drag. This is where two tailfins can help create the endplates to help pull air out of the tunnels under the car increasing the air speed and hence lowering its pressure (benouli effect). This is my favourite sort of design where everything is working holistically to create one great solution but I need to know the pros and cons of each element to see how best they go together to cancel each others cons and promote the pros.

Why use ground effects? Well the trend for streamliners has been to be narrower and more dart like. We don't have this option as we will be using the existing setup but that means we have both pros and cons. The cons are wider frontal area but one pro is that that gives us space to use ground effects tunnels either side of the car which can give us more downforce for cheap if designed correctly (and admittedly this is a big if). I have a design hunch that the simple solution of a dart is not necessarily the fastest solution for a wheel driven car. It's fine for a rocket, Bloodhound SSC, Aussie invader etc, but they want to be as neutral as possible. Wheel driven cars need to get that power to the ground and the options are weight or aero downforce. Weight is part of the solution but there is a limit, for example, you still need to be able to get up to speed in the 7 miles and if you are two heavy for your power that is simply not going to happen in that distance. Being lighter means you can accelerate quicker (if you can get the power to the ground) which means you should be able to go faster over a given distance given the right circumstances. What I am trying to figure out is what those circumstances are and design our car for that gap in the market!

Hopefully will be visiting this September Sum! Would you believe that Alice, our daughter who Amber was pregnant with when we visited you, is now in primary school???!!! It's been way too long. Please say hi to Ruth too, I still can taste in my mind her delicious dish she cooked for us.

Dik





Offline Reverend Hedgash

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Re: Australian Belly Tank
« Reply #4142 on: December 23, 2013, 07:46:13 AM »
Looking at your concept drawings of the conversion to a streamliner reminded me of Bob Herda's liner from the 60-70's, and it has a tail fin! Bob ran as high as the 340 mph range before his tragic death. Another thought would be doing something like the Frank Lockhart car which is really just a lakester with wheel covers. This car was calculated to be able to go over 300 with the supercharged V16 Miller engine it had. Tires were the problem and what eventually caused the accident that killed Lockhart. One of the things that probably would need to not be copied from the Lockhart car would be the front wheel covers turned with the wheels, I would think this could be a problem over 200. Probably best to make them wide enough to be able to turn the front wheels inside them. Just some thoughts.

Rex

Thanks Rex, yes it looks a lot like it but I hope it doesn't end up looking like it as I want to design something new! Some excellent looking form making going on in that selection though but it is hard to see some of the science and whether it works.

What our design has slowly evolved into now though is closer to the Beast III. This was designed by a very clever aero guy Rod Schapel for Chet Herbert. What a great looking car and apparently very stable too so very happy to have found this even though I actually arrived at this look from a different angle. They extensively wind tunnel tested models so some good science in there too so that gives confidence.

The reason for the change in ours at the moment is I have been thinking about the salt leaving the tyres of the car and its impact on the car itself. Depending how wet the surface there is there can be quite a rate of projectile of salt giving the rooster tail behind that we know and love. But this salt is exiting the tyre at quite a speed backwards relative to the car and so if it is hitting the inside of the car's body then it is transmitting its energy to the car and slowing it down. This might not seem like much but if you have seen how much damage a sand gun can do then that is only the start. At travelling over 300kph the sand has a kinetic energy of 1/2mv2 (m in kg, v in ms-1). If a grain of sand weighs about 0.0026g then the grain has a kinetic energy of 117kj hitting the body of the car in the wrong direction and given how many grains will be hitting the body from four wheels that quickly adds up! Given its a square law the faster you go the more significant it is like aero.

So I have been looking at sculpting the rear section behind the wheels out in a smooth way has led back towards the twin teardrop shape of the Beast III!

Every little bit counts and close enough is simply not good enough in LSR so trying to cover the small and the bi ticket items, also I am looking for those rational design devices that lead to a new concept and who knows where it might come from?

Dik
« Last Edit: December 23, 2013, 08:12:35 AM by Reverend Hedgash »

Offline superleggera

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Re: Australian Belly Tank
« Reply #4143 on: December 23, 2013, 01:43:30 PM »
Question: does your proposed new design taper in width from front to rear -- or fixed width?
- me: Mark - home: Dry Heat, AZ USA - build: motorcycle streamliner

Offline SaltPeter

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Re: Australian Belly Tank
« Reply #4144 on: December 23, 2013, 06:42:22 PM »
I know Land Speed designs usually require very different to other forms of motorsport,

however in this case would Le Mans Prototype designs be worth a look, especially LMP2 Class Cars Underbody and Rear Diffusers?

Some basic info http://www.symscape.com/blog/secrets_of_diffusers

Pete 

And Merry Christmas to all :cheers:
The Mission is to go as fast as possible along on that old Road Less Traveled.

Offline tauruck

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Re: Australian Belly Tank
« Reply #4145 on: December 24, 2013, 01:45:29 AM »
Here's what I came up with/found by accident. :-D

Maybe a similar version and using the bits that work for you?.
« Last Edit: December 24, 2013, 01:47:07 AM by tauruck »

Offline Reverend Hedgash

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Re: Australian Belly Tank
« Reply #4146 on: December 24, 2013, 04:47:59 AM »
Question: does your proposed new design taper in width from front to rear -- or fixed width?


Our existing wheels run behind each other at a normal axle width. The front wheels will need to be able to turn which is something to behold when they have 30 degrees angle and castor, they sort of flop over left and right rather than turn like a normal car. Although we need minimum turn for racing we still need useful turn for getting around the pits etc so it will be designed for maximum lock.

With this in mind the width of the car is heading toward being wider at the front than the rear to allow for this movement of the front wheels which ties in with the most aero shape being a teardrop with the widest point about a third down the chord. So to answer your question I am trying to grow and then taper the plan of the car in a way that best opens and closes the air which will be some soft curves.  This will be tested in our software.

Reverend H+

Offline Reverend Hedgash

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Re: Australian Belly Tank
« Reply #4147 on: December 24, 2013, 04:56:03 AM »
I know Land Speed designs usually require very different to other forms of motorsport,

however in this case would Le Mans Prototype designs be worth a look, especially LMP2 Class Cars Underbody and Rear Diffusers?

Some basic info http://www.symscape.com/blog/secrets_of_diffusers

Pete 

And Merry Christmas to all :cheers:

Exactly! Not only different requirements but LSR has different rules which allow what is not allowed on track cars. Skirts were banned on formula 1 because they cornering became dangerous when they failed but that is not an issue for LSR. Also the rules of track racing dictate how high, wide, long etc each element can be yet in Special Construction we don't have such limitations so go for it is what I say. (remembering safety though).

The prototype designs of Le Mans are good fodder to investigate I agree and as mentioned before I do love the long tails.
Thanks for the link.

Dik

Offline Reverend Hedgash

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Re: Australian Belly Tank
« Reply #4148 on: December 24, 2013, 05:01:46 AM »
Here's what I came up with/found by accident. :-D

Maybe a similar version and using the bits that work for you?.

Yeah this is one of the big aero newbies and seems to be doing the job. Good thinking outside the square in this one. I guess we could make an alternated front axle pretty easily and change the track width so it is not out of the question this approach. One alarm bell in my head is narrowing the width reduces the straight line stability as the driving wheels are outside the steering wheels whereas ideally you'd have the steering wheels outside the driving wheels.

Must be hard racing with those rear wheels, like trying to pass a car towing a wide trailer! At least other open wheelers have the front wheels to line up the gap.

D

Offline Dr Goggles

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Re: Australian Belly Tank
« Reply #4149 on: December 25, 2013, 06:20:36 AM »
Happy Christmas everyone from the Spirit of Sunshine Landspeed Laboratory,Possum Park and Idiot Wonderland, and I mean everyone.

I dont care who you vote for, worship or play for, what you ride, run or wreck, take a day off and have yourself a great day, make some people happy and enjoy yourself.

Cheers, :cheers:

James "Dr Goggles" Stewart
DLRA #374
Few understand what I'm trying to do but they vastly outnumber those who understand why...................

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THE LUCKIEST MAN IN SLOW BUSINESS.

Offline grumm441

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Re: Australian Belly Tank
« Reply #4150 on: December 25, 2013, 07:12:51 AM »
Happy Christmas everyone from the Spirit of Sunshine Landspeed Laboratory,Possum Park and Idiot Wonderland, and I mean everyone.

I dont care who you vote for, worship or play for, what you ride, run or wreck, take a day off and have yourself a great day, make some people happy and enjoy yourself.

Cheers, :cheers:

James "Dr Goggles" Stewart
DLRA #374


yep
G
Chief Motorcycle Steward Dry Lakes Racers Australia Inc
Spirit of Sunshine Bellytank Lakester
https://www.dlra.org.au/rulebook.htm

Offline SPARKY

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Re: Australian Belly Tank
« Reply #4151 on: December 25, 2013, 08:40:34 AM »
Well said SIRS    :cheers:
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline SPARKY

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Re: Australian Belly Tank
« Reply #4152 on: December 25, 2013, 08:46:16 AM »
Why would you have 30 degs of castor in a liner?
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline Stainless1

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Re: Australian Belly Tank
« Reply #4153 on: December 25, 2013, 11:51:25 AM »
They don't, they have 30 degrees in a lakester... they are looking to re-body to a liner.... maybe....
Depends on which wild hair is controlling the brains of the participants at the time....  :roll:
 :cheers:
Stainless
Red Hat 228.039, 2001, 65ci, Bockscar Lakester #1000 with a little N2O

Offline Ron Gibson

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Re: Australian Belly Tank
« Reply #4154 on: December 25, 2013, 12:19:35 PM »
Why would you have 30 degrees caster in a lakester?????

Ron
Life is an abrasive. Whether you get ground away or polished to a shine depends on what you are made of.