Another belly tanker, QLD

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sammj
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Another belly tanker, QLD

Post by sammj » Thu Jun 10, 2010 11:47 am

Hi all.
Long time reader, first time poster :)
I have finally found a mate mad enough to commit to helping out in the build of a salt lake racer, as I know two heads are better than one and it keeps thing motivated.
In true Aussie style we want to do things cheaply and simply and go from there (famous last words).
As we both has VW experience having had a host of Beetles and Bajas, and the fact that we have heaps of bits lying around we want to use mainly VW running gear.

The basic plan. Use and air cooled VW motor and box mounted mid engine stlye (like a formular vee) and use a modified VW front beam, seal it all up in a fibreglass belly tank. Simple :)
Obviously its not going to be lightning but should be fun enough.

I have been reading all the other belly tank builds and have a list of questions already and have downloaded and printed a rules book so thats a start.

The first question - Is suspension neccesary in such a lite construction? I have noticed a few dont seem to have any at all.

I'll throw up a few pics of some toys ive already made cause basically the build, at this stage, is a pile of parts, an engine and some chaulk drawings on the shed floor.

David Leikvold
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Vee!

Post by David Leikvold » Thu Jun 10, 2010 1:06 pm

Welcome to the forum Sam, anyone who wants to build a Vee style lakester is all right by me! You could do a lot worse than follow the example of the Doctor Goggles / Reverend Hedgash car, there isn't too much to argue about with a car that goes so well with a Commode door engine :wink: .

If I was designing a VW lakester I'd also be looking hard at the current crop of Formula Vees. If you can get to Morgan Park in Warwick on 3 & 4 July you'll come home with a million ideas. Take lots of photos. There are plenty of Vee websites that will also be very useful. I'd be keen to use a swing axle gearbox with the 4.125 diff with leading arms instead of trailing arms. The standard rear drum brakes will suffice unless you already have a disc brake setup just lying around. In fact just copy the whole back end of a winning Vee and you won't go wrong. Use proper suspension front and rear, there's no advantage to running without it other than avoiding the cost of a few springs and shocks. It will also reduce the risk of bending and breaking things from running without it. Ditch the fan housing and generator and run a pair of cooling fans over the cylinder heads instead. For the front end I wouldn't use an H-beam unless you had one lying around as they're a bit aero-draggy. If you have a link pin one handy use that with the drum brakes, they'll be fine. Ideally I'd use ball joint front uprights with the OE 4 stud disc brakes and Formula Ford style wishbone arms made from oval section furniture tube. The current ball joint Vee front end with bell cranks to inboard shocks is probably a good compromise.

Somewhere else on this forum Rob (I think it was) posted dimensions of a P38 belly tank. The tank is 12.5ft long, which is about 22" longer than a Vee. Here are the diameters at 1ft intervals. 0: 0", 1: 18.5", 2: 25.5", 3: 31.0", 4: 34.5", 5: 35.5", 6: 35.5", 7: 34.0", 8: 30.5", 9: 25.0", 10: 18.0", 11: 12.5", 12: 7.5", 12.5: 0". If you stick as close to that as possible you'll have a very slick shape and probably enough headroom too. You'll notice that most Formula Vees are only about 24" wide at the firewall so, again if it was mine, I'd stay with those listed diameters for the profile view but keep it as skinny as possible to minimise the frontal area. The car does not need to be that extra 11.5" wide. You have to remember that belly tanks were designed to carry fuel efficiently, not race cars. Let the cylinder heads hang out in the breeze a bit, they'll thank you for it. I'd also consider putting a small flat bottom section under your seat, as Dik and James did, that will help lower the car a few more inches.

You could scale all that down if you wanted to keep the car a bit shorter but a bit more length than a Vee would be handy for getting in and out of the lakester with a full roll cage. That's enough for now. Good luck.

Cheers
Dave :D
Good, Fast, Cheap, pick any two!

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Dr Goggles
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you beaut

Post by Dr Goggles » Thu Jun 10, 2010 2:44 pm

If you're determined to use VW bits so be it. The most important thing is that you have fun, what anyone else thinks is secondary. I have a warning though. Once you get the thing up and running you will be a lost cause for this game,you will want to go faster, and faster .A car that is built around an aircooled/transaxle may limit your scope to really indulge yourselves.

I wrote this as advice toanother Aussie who was kicking off...

I've got a couple of suggestions and they are by no means aimed at you personally.I'm going to put them down line by line because I'm not(for once ) up for an essay right now.

It has been said many times here , everything has been thought of , lots of it done, some of it worked.....so find as much LSR history as you can...the good the bad and the ugly, the bold and the beautiful,look at 'em and read what they did.Some very clever people have been at this game, there have also been some mad ones and some very rich fools, learn from their experiences.

If you're going to be true to what you wanted when you started you first have to finish.This can be horribly expensive, if you bite off too much you'll have a half finished thing that has sent you broke.

This game is a battle between power and drag, you need to convince traction to be your friend. Power you can get at the shop,most people have more than enough.Drag is something your design will dictate and your design is prey to thousands of different factors.Keep it simple , have a reason for everything you do, not a hunch.

The rules. There are very specific minimum requirements related to safety, learn them off by heart and begin your design there. They dictate the smallest possible area you can sit in.

Learn the basics of aerodynamics, it's not likely you'll ever get to a wind tunnel so apply the knowns, the unknowns are bad science .

There are a lot of records up for grabs in the DLRA, but you're not the only person building something........have a really good look at the Budfab motorcycle streamliner, something along those lines is conceivable, aiming for 300 is a serious step for a self confessed newbie.

Go for it brother. If it wasn't for a shipload of naivete we would never have finished our car but that said I feel like the blind bloke who just walked across the freeway, I survived but I dunno what I was thinking when I started.


Having two heads is a good start, don't kid yourselves you can do it cheaply.

When you build a "salt" car it is different to everything else, if you just adopt something it will be a compromise.

Treat it like a tender. What are the requirements? Aim for the basics and keep it as simple as you possibly can.

Good to see you come out of the woodwork, welcome. :wink:

Dr G

Ps. Just in case you missed it...

http://www.landracing.com/forum/index.p ... 862.0.html
...few understand what I'm trying to do , but they vastly outnumber those who understand why..

David Leikvold
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feedback already

Post by David Leikvold » Thu Jun 10, 2010 4:53 pm

Well, there you have it Sam, wise words indeed from the Good Doctor who's already been there, done that, gone 193mph. As he said, don't be discouraged by the people who don't understand the lure of the people's car. It's like flatheads or postie bikes, you either get it or you don't. The SCTA rules are designed to suit almost everyone with an interest in speed, whether that be 100mph or 400mph. Make sure you take the time and care to build a car that you can be proud of, something that impresses everyone who sees it and something that breezes through scrutineering all the while getting envious looks from those people who do none of the above.

Doc, any lakester that can fit a driver and a VW flat four will also be able to fit any number of other engine/gearbox combinations if the engine bay is well thought out. If they chose to upgrade later on to a turbo Subaru (for example) and converted the Subi gearbox to 2wd they could probably give you a run for your money and still sound like a Volkswagen :wink:

Cheers
Dave :D
Good, Fast, Cheap, pick any two!

sammj
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Post by sammj » Thu Jun 10, 2010 7:50 pm

Heres a few picks of my current cars.

The ute is a HQ which was modifird by the previous owner to look like a elcameno, notice the rear of the cab. I added a worked 308 and automatic gearbox, changed to white wall tyres and put it back to bench seat and column shift. Currently has 3.55 diff gears which are too much so going back to 3.08s soon.

The "rip off" buggy I brought as a project in 2008. The only thing left of the original is the main hoop and fibreglass. I basically paid for rust :) But it was easier than starting from scratch. It apparently is an early, 1970, sportsman class offroad racer. This photo was taken just prior to completion.

The "blues mobile" is a HQ sedan which was built to use in the standard class of mud racing such as the roma mud derby. It too has a worked V8, 3500 stall and I welded up the diff for good measure. It unfortunately hasn't seen the mud yet but get regularily driven on our bush track.

Image
Image
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Dr Goggles
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Re: feedback already

Post by Dr Goggles » Thu Jun 10, 2010 10:30 pm

David Leikvold wrote:Well, there you have it Sam, wise words indeed from the Good Doctor who's already been there, done that, gone 193mph. As he said, don't be discouraged by the people who don't understand the lure of the people's car. It's like flatheads or postie bikes, you either get it or you don't. The SCTA rules are designed to suit almost everyone with an interest in speed, whether that be 100mph or 400mph. Make sure you take the time and care to build a car that you can be proud of, something that impresses everyone who sees it and something that breezes through scrutineering all the while getting envious looks from those people who do none of the above.

Doc, any lakester that can fit a driver and a VW flat four will also be able to fit any number of other engine/gearbox combinations if the engine bay is well thought out. If they chose to upgrade later on to a turbo Subaru (for example) and converted the Subi gearbox to 2wd they could probably give you a run for your money and still sound like a Volkswagen :wink:

Cheers
Dave :D

The main problem with transaxles is available final drive ratios but if you can build a motor that'll rev over 8 grand it won't be an issue.......but building those sorts of things or getting gears cut is expensive....hmmm, that's what makes this interesting....
...few understand what I'm trying to do , but they vastly outnumber those who understand why..

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T-34
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Post by T-34 » Fri Jun 11, 2010 1:44 am

Hey guys, great to see someone else taking the plunge with some VW power. Personally I think that as a power plant the VW base is fine - but then I'm a little biased ;)

VW style transmissions can be a bit tricky - there isn't really that many ratios available from the stock VW range, BUT there are a more or less unlimited range available from aftermarket sources, but unfortunately you will have to part with some $$$'s for the privilege.

For the ultimate, take a look at Hewland gearboxes, the early versions were based on the VW box, but they now have bespoke cases. Complete boxes / ratio sets are still available. There is also the possibility of picking up a used unit from a formula three car. These are expensive, but you might get lucky. http://www.hewland.com/svga/mk9.html

Rancho boxes also offer a variety of ratios, although not as many as Hewland. If you go this way, give me a holler, I can put you in touch with a Rancho importer here in SA.

The other option is to use a Porsche box - you can use a 901 (fitted to early 911 / 914) this does not offer too much of an advantage over the stock VW box and has a dog-leg shift pattern (a right PITA IMHO).

Next up is a 915 box from an 80's 911 - these are a 5 speed unit and should be good for what you need. plenty of aftermarket ratios available. Does suffer from stiff shift and overheating when run for extended periods - no issue at all over the distance travelled here tho.

If you've got some extra $$$'s you could go with the G50 - this is the successor to the 915 box and also came in a six speed version - again all the ratios you need to go well over 200 in a road going 911 - so will deffo have some to suit your needs. Very strong box, does not suffer from 915 issues, but is a very spendy bit of kit.

I personally have a 915 from a 911 SC in my project car - this was good for about 150 - 160 in the 911 - Factor in some tyre diameter changes and the stock box might work out good for you. Can't really comment on how successful it is in my car as I wasn't finished in time for this years event. :(

There are already a couple of VW lakesters out there, would be good to see one here in Aus. Was considering building one myself, but need to get one project out of the way first.

As some inspiration, here's a couple of pics

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Been trying to find out more about this one - a VW powered lakester featured in a US magazine.

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Dick Beiths 36 horse powered 1963 VW lakester record holder of 129mph (record still stands)

And here's what he's hoping to beat it with at Bonneville later this year - an insane beetle based streamliner

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Good luck, and if you think I can be of any help - just give me a holler.

Mick.

PS - If you're interested, there's a great interview I did with Dick Beith in our online ezine - follow the link in my signature - there's also a VW salt racing group there too.
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Post by T-34 » Fri Jun 11, 2010 1:53 am

Ahhh yes - got a couple of contacts for glass lakester bodies in states too - if you decide to go that way.

Mick.
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T-34
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Post by T-34 » Fri Jun 11, 2010 2:04 am

Just a thought. Have you considered how the axle configuration would work out? ie how to keep the axles straight?

Mick.
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sammj
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Post by sammj » Fri Jun 11, 2010 11:35 am

A perplexing problem the rear axle configuration! The torsion tube and spring plates are definately not aerodynamic.
I have been looking at formular vee set ups and found this one www.1302super.com/shrike_bigvee.jpg at http://www.1302super.com/page8.html

So the idea ATM is to replace the function of the spring plate with a coil over shocky and use a leading arm. The problem is getting the front pivots of the trailing arms the same width as the axle tube pivots on the gearbox. Alternatively, could go with trailing arms like this frame
http://www.scottandrew.com.au/art/racing/

This frame also shows the modified VW front end with the shock towers removed and the shocks tucked behind the torsion tubes,

Looking at formular vees frames Im growing in confidence that it will all fit inside a tank!
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David Leikvold
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easy

Post by David Leikvold » Fri Jun 11, 2010 11:48 am

Sam, use the Vee style leading arm setup with a single transverse coilover mono-shock. It's simple, effective and doesn't hang stuff out in the breeze. If you wanted to really tidy it up you could cover the area between the axle tube and the leading arm with an aero-shaped cover made of aluminium or even fibreglass. Go look at some more Vees, they've all got different ways of achieving the same result, the fast ones just do it smarter.

Cheers
Dave :D
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Post by T-34 » Fri Jun 11, 2010 1:39 pm

The rapier setup looks pretty neat, obviously designed with some care too. I especially like the idea of the airbag setup. Wonder if plans are available?

I guess you could also go for a solid setup and simply fix the axle tubes to the frame somehow

For the front, you could fab up something from scratch and get rid of the double torsion bar setup - maybe use a pair of king and linkpin spindles but mount them to a single bar instead of the trailing arms.

IIRC DrGoggles your setup is something along these lines...

Image

Mick.
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Boing

Post by Dr Goggles » Fri Jun 11, 2010 2:34 pm

T-34 wrote: IIRC Dr Goggles your setup is something along these lines...
Image
Mick.
Our set up is so similar to that it's creepy, Oh , hang on that is our set up.......We have two bits of rubber 12mm thick that the axle mounts bolt through onto two little perches on the front of the car.The axle is 44mm 6mm wall CDS tube with EH holden king-pin bosses, steering arms and spindles. and '36 ford bones .We got the tie rods made up and used EH outer ends and Laser ones for the inner because that's what we had.

What you can only see if you are lying on the ground is that it all lines up so the only thing the wind sees is the axle.

For the umpteenth time ( I am talkin here about a metric Umpteen, which is between f***in heaps and more than I could be bothered counting) I will explain our decision to not use suspension. When we looked at cars that were running we found that many had suspension that was screwed down so hard it barely functioned, then when we followed peoples development over time we found they reduced their travel in an effort to increase stability. The real problem in high speed stuff is the rebound( witness prod cars that "backflip"), though not so critical for a tank or any other narrow body shape.

The untidy aero, the lack of space and the complexity were factors against suspension for us. Any suspension travel also need to be built into the ride height and we wanted that to be minimal.The final straw was that we felt unable to decide what would be "appropriate", how to get the spring and damping rates right....in the end it all got into grey areas. A suspension system that has a response rate to handle speeds over 200mph and travels under an inch is out of the realm of a back-yarder despite what many people think.Discuss.

Now I can hear people thinking "well, something is better than nothing!" to them I say , no suspension is better than a set up that bottoms out, or "bounces"............ as always though I'm more than happy to be proved wrong
...few understand what I'm trying to do , but they vastly outnumber those who understand why..

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Discuss

Post by David Leikvold » Fri Jun 11, 2010 7:10 pm

How am I supposed to get any work done today with you posting interesting stuff all the time Doc? :wink: . Discuss I will.

You're right about suspension introducing plenty of variables but Sam does not need to re-invent the wheel, the answer is simple and already well proven. The Formula Vee swing axle rear end works very well in circuit racing around the world and has done for more than 40 years. It would be the ideal solution for a VW lakester. Limiting suspension movement / ground clearance / camber change is dead easy, just run a very hard coil spring with a progressive bump stop almost touching at normal ride height and have a tranverse rod or cable arrangement that does not allow any more droop than zero positive camber (easily checked by jacking the rear wheels off the ground). Every Vee in the country uses this setup. They work so well that Ralph Nader wants them retro fitted to all remaining Beetles! The minimal movement allows for a bit of give in the car and stops things bending and cracking.

The same theory could be used at the front. A sprung beam axle would be a nice compromise between your setup and an aero-draggy VW H-beam. If it was mine I'd probably make a round axle covered with aero tubing that had brackets that bolted to the standard link pin front stubs, that way it uses more of the off the shelf parts that Sam already has. I'd locate it as you did with arms behind it but I'd use short aero section tube that came from the chassis at about 45 degrees and bolted to the axle as close as possible to the wheel with two well spaced bolts to resist braking torque better. These could be adjustable for caster angle changes if required. For lateral location a Watts linkage inside the body would be perfect, although a Panhard rod would probably suffice in the circumstances. As an alternative another longitudinally mounted Watts linkage would provide the resistance to braking torque and provide caster adjustment. A single coilover shock centrally located would hold everything off the salt and a U-shaped sway bar would fit in there nicely because the teardrop shape gets fat fast. There are better ways of incorporating a smaller and neater sway bar into the mono shock setup but I have no idea what machining facilities Sam may have access to.

How might this be better than solid? The compliance that suspension introduces would mean the front axle was not heavily loaded in bending, it would also eliminate any chance of double vision from vibration and make for a less jarring ride. A VW steering box could be mounted in almost the original position so there would be no bump steer either. All of this stuff would fit easily because the P38 tank is 24" longer than a Vee and the engine and transaxle would come no further forward than about where your rear trailing arms bolt to the chassis. Legroom galore!

By the way Sam, don't even consider using that American Vee trailing arm with the bend around the cylinder heads, it's a really BAD idea. Apart from hanging out in the breeze too much, its other fault is flex. Nobody fast in Australia has used that design for 30 years. As the arm flexes with one wheel bumps, the swing axle moves and steers the car. You don't want that. I presume they only use that design because their rules don't allow leading arms mounted at the back of the gearbox, there could be no other reason. Don't use any of their chassis ideas either, Americans just don't understand space frames. That car is essentially a ladder chassis with manifestly inadequate driver protection. If that thing went over at max rate you would be killed for certain. You must look at local Formula Vee (Jacer is good) and Formula Ford (Van Diemen, Mygale, Swift, etc) chassis designs to see what should be done. Look at the winning cars, they're designed properly. There are Vees at Lakeside this weekend. When you design your chassis you just need go a bit bigger in the tube sizes for added strength, and don't forget that for the salt weight is not a consideration.

Cheers
Dave :D
Good, Fast, Cheap, pick any two!

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Post by penny » Fri Jun 11, 2010 7:56 pm

t 34, mick dont even think about buying this paul http://www.racingjunk.com/category/17/A ... gster.html
glengowrie annexe of the Institute of Backyard Studies

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