hi all. Im doing a few sketches of a middy project i have lined up. Base on a sierra track of 54 inches, i work out from the 1.6 rule that the car wants to be around 86 inches wheelbase. Unfortunately, my sketches come out at 114 inches long, about 2 and a half feet over. this allows 12 inches for the front bones, 72 for the cockpit, 30 inches for the longtitudinal bike engine and another 12 for the back wishbones. The cockpit is this long due to the reclined driving position, as a result the car is only 30 inches tall, from floor to rollbar/roof (it has a full roof built in).

so, as i need to reduce the length a bit, am i best off shortening the cockpit area, or just moving the front wishbone back so that the pedals are infront of the springs? the cockpit might go down to 60 inches, infact ive just measured it on the floor and i think i would manage, with tidy pedals.

so that takes me to 102 inches, from the centers of teh wheels. Still 18 inches over the target, or if left, a length-width ratio of 1.9.

any thoughts anyone?

ps the bike engine has to be longtitudinal cos there will be two, side by side. chain driven to the diff.

It's a bad idea having your feet ahead of the front axle line. In a frontal collision you won't be walking away from it... This is bad on the track, and worse on the street. If this is for the street, I'd say 30" is bad since you'll be virtually invisible in people's mirrors and you'll be "squeezed out" often. 40" minimum would be good. OTOH if it's for the track then yes, the lower the better.

You can move the front wheels as far back as where your knee's are if you're not running into width problems though.
You can also pinch something from the engine bay 'cause 30 inch seems more than enough.
All in my very humble opinion though.

thanks for the comments so far guys.

kb. it will be a mix of track and road, probably more road though cos its free! you comments about feet make sense, thanks.

cita. im off to measure the zx9 lump now. I need to leave a little extra room for the gubbins required to make the engines work together. Might flip one around, so the exhausts are both on the outside, one engine chained and one cogged to reverse the spin.

more comments welcome.

[Edited on 16/8/04 by JoelP]

Just an idea:why not place the engine's in tandem on top of each other?
It may seem stupid at first but it will save a lot of fiddling around with the power supply to the diff or axle.
The bottom engine can be placed real low in the frame so the CG will be not that bad.

I read a book about the original 750MC racers. For some of their middy layouts they have the engine basically where the passenger sits, but if you require it to be a 2 seater you can forget that!
All the best

About the 30" for the engine and 12" for the back wishbones, can't those overlap some?

Since it's for the street I'd really consider "scrunching it up" some and making it taller, 45" or so. Getting taken out by an SUV is no fun, they have a hard enough time seeing out as it is...

TextOrangecolor=White]TextWhite[/color]
best wishes
Iain

KB are you talking about length or height?

Thank you very much Ian

TextTextOrange
I am just wondering how you are going to syncronise two engines and seperate gearboxes ? And have you considered the transmission losses in your proposed set up? seems like a wrong headed aproach to me that looses lots of the virtues of a bike engine in a car . or is it a desire to have a bigger lot of whirring bits than any one else on the road? Any way if you stick to one engine there is always the posibility that as the cylinder head and carbs/ injectors would be on the left that you could have an asymetrical cockpit and have a smaller/ shorter space for your passengerand have the shorter wheelbase you desire.
best wishes
Iain

well, heres my advances and changes.

from the centre of the rear wheels to the bulkhead in front of the engines, is now 36 inches. the engine is about 20 inches long. i have spun one round, i figure if im gonna work out a chain drive for one i may as well work out a pair of cogs for the other! plus, the off side engine (uk drivers side) would've needed the cog extending out from the engine to clear the block, as the chain would head the wrong way to usual. so that that bit sorted. PLus the exhausts will both be ouside, and the carbs both (all?) inside.

so that 30 inches used. By raising the cockpit/rollbar bit to 36 inches, and making the pedals almost touch the steering rack, ive managed to get the centre of the front wheels to 54 infront of the engine bulkhead. hence total wheelbase is now 90 inches, the ratio is 1.66

the cockpit is 48 inches wide at the back of the seat, but it narrows continually to 24 inches wide at the front, which is the width between the two top front bone pivots. this is wider than book dimensions (i guess 'book' dimensions went out of the window hours ago though!), but this allows some space for feet near the rack. the drivers feet will point into the middle of the car a little, and the passanger will have no footwell. or at least, the driver has priority!

the reason for the odd cockpit layout is that i never liked the way that book chassis have a kink in the side under the scuttle. its a pet hate. seems to be unbraced and as such will add a little flex to the chassis. My way it ends up like a 2 part chassis, namely a front suspension box, the cockpit with straight sides, and the engine/diff area on the back.

Rear drive is via a simple LSD, probably freelander origin, and a de dion rear axle. Its easy to link it up to the chassis.

Having an integral roof will allow a much stronger roll bar, or a thinner/smaller one, however i decide. plus the chassis will benefit from the extra bracing.

it does look very odd in profile, being 36 inches high and only 90 long, but i guess bodywork will cover that.

seats will be foam on the floor, shaped to be supportive. Fuel tank will be squeezed wherever it will fit, ideally between driver and passanger, but maybe not. The wheels will be 13 inch ally ones (maybe magnesium if funds allow) and cut slicks for road.

i feel motivated now! just need to wait for the remortgage (litereally!) in a few weeks.

there will be a few posts coming up soon about the correct use of bearings on the prop, as the drive will be transmitted from the engines to a prop via the chain and cog, and the prop to the diff as usual. bearings will be used to hold the free ends in place.

oh yeah, rosejoints all round i think. Anyone know how wide the brackets will need to be roughly to take 1/2x1/2 roses?

more input welcome of course, ridicule too if you feel the need!

cheers iain, the real reason behind the choice of drivetrain is twofold. One, to see if i can. And two, linked to that, one day it will be a pair of turbo'd busas. Hence this car is 'proof of concept' sort of stuff.

i appreciate what you are saying, about the main bike advantage (weight) being squandered. Still, it will be a laugh, unique, and like poo off a wet shovel!

[Edited on 16/8/04 by JoelP]

best of luck you guys in blighty have MUCH MORE SCOPE than us residents of the antipodies to build something out ragious for the road . here we are much more restricted , all of our cars have to meet Current emission and design requirements and bike engines are forbiden in a car.but the othe side of the coin is our weather is better most of the time , at least where we live in Queens land
best wishes
Iain

horses for courses!

Hi JoelP

Have you seen how Z cars use twin engines in their mini ? Looks very compact

http://www.zcars.org.uk/mini/mini_twin_rl.htm

Adrian

theres some interesting jiggery pokery going on in that transfer box! looks complex. shame i cant make that sort of thing...

You could save a lot of aggravation if both your engines had the output shaft pointing rearwards. Then you could have the LH engine mated directly to the driveshaft and the right one could use a chain drive to transfer power over to the driveshaft.

Kinda like this (except longer so you can fit the driveshaft onto the output of the other engine):


What do you think? That way you wouldn't have to revese the rotation of the right side engine via a secondary gearbox.

thats exactly what i was going to do in the first place! i decided to switch one engine round to save the length of the sprocket extension, as shown in your picture. it would also put both exhausts on the outside of the car. Maybe this isnt such a problem. I had initially decided use a chain drive to link each engine to a central freespinning prop, with the diff at one end and a bearing at the other. I like the idea of having one engine straight onto the prop, however on a UK car this would put the engines over toward the drivers side, and a less favourable weight distribution.

im gonna go out and measure the block, and imagine two side by side. I've only got one engine so far...


cheers for the input!

Do the halfshafts need to be the same length exactly? Theres no steering back there after all so you shouldn't get noticeable torque steer effect. If you can shift the differential and both engines over to the right side by say 10-20cm you can shift the weight balance to the center better. It seems like that packaging should work...

I assume you will run the 2 headers into one centralized resonator and then out the back from there? That would probably sound incredible anyways! I can see that you will probably have to bespoke the headers/ exhaust anyways...

steve, thats an awesome idea, moving the diff over to one side.... why didnt i think of that?!

back to the twin bike transfer box again
unless i am missing something there is nothing crazy or complex about it in fact if it is this one



i was amazed at how simple it was!
linky thing

as ever i am pleased to be proven wrong
please if someone could tell me what is special about it
it costs £2500

[Edited on 17/8/04 by liam.mccaffrey]

steve.

moving the diff over affects the de dion bar, but this isnt the end of the world.

Liam, any idea how that thing gets oiled? Would a splash system work, with say an inch of oil in the bottom? seems to be simple cogs, bearings and machining involved.

if you could throw a diff into this transfer box, then you would have an excellent piece of kit

[Edited on 17/8/04 by JoelP]

i think it has its own seperate oil system, this is implied on the website


all the gears are off the shelf, bearings no probs, machining no probs lathe and miller, only thing would be the casting not too difficult if you are in a serious mood.

if the worst comes to the worst you could fabricate something and tidy it up by machining. stuff £2500 i bet i could make that for £800

please someone tell me i am talking through my arse(tell us why it can't be done)

[Edited on 17/8/04 by liam.mccaffrey]

leave it a day for any experts to comment. Id bet a lot less than £800 too. The housing wouldnt need machining i think. the two end plates i would outsource to someone competent. simply flat steel, maybe just 10mm, with large holes drilled to take the bearings. Maybe 50mm? stick bearings in, weld cogs to thinner bars, maybe 25 or 30mm, stick these into the inner race. make a triangular housing out of 10mm by 100mm bar, grind it nearly flat, and fill the gaps with gasket sealant. Tap holes to hold it all together. I would weld mountings onto the end plates. not sure how to seal the outputs and inputs, but it cant be rocket science...

i have asked this question before more than once, and have not got any answer.

i'm thinking this conversation is sounding like a plan/challenge

great! we can both add this project to the LIST OF IMPORTANT THINGS TO DO SOON.

i'll let you know within 10 years how it goes...

heres a link for bearings:

http://www.rmbearings.co.uk/zkl/contents.htm

i think a suitable one would be the single row deep groove ball bearings, 13mm thick, 30 shaft diameter and 55 outside diameter. Rated up to 3000 pound feet and 12000 rpm.

any thoughts on this, anyone?

also, anyone know what rs stands for on these diagrams:

http://www.rmbearings.co.uk/zkl/B2_15.PDF



[Edited on 17/8/04 by JoelP]

I believe rs has something to do with the sealing of the bearing(side flanges)
Could be miles off though

quote:

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Originally posted by JoelP
anyone know what rs stands for on these diagrams:

2RS and 2RKdenote contact type seals, ZZ denotes shielded type and 2RD denotes light contact seals.

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TheGecko - 18/8/04 at 06:37 AM

quote:

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Originally posted by JoelP
also, anyone know what rs stands for on these diagrams:

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Joel,

I suspect it's the shoulder radius - on the second page it's ra and the dimensions list shows abutment and fillet dimensions. That's why it's shown where it is on the diagrams and why the numbers are so small.

Could be wrong too

Dominic

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JoelP - 18/8/04 at 06:59 AM

good point dom. i might just buy one and see!

[Edited on 18/8/04 by JoelP]

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pbura - 18/8/04 at 11:05 AM

Isn't the Sierra track 57"? That would give you 91" for the wheelbase for 1.6:1.

Job done

Pete

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JoelP - 18/8/04 at 05:35 PM

umm... possibly. i was measuring fron the center of each wheel, which would explain the difference!

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BenRelle - 19/8/04 at 08:30 AM

You might want to get down to the Brighton speed trials later this year. Last year there was a twin 'busa engined car with a mid mounted config driving rear wheels. He had both the engines driving a common shaft via their normal sprocket and chains, and then another sprocket and chain to the diff and so to the wheels. It was an awesome machine. From the look of that car and the times it posted, you won't need those turbos.

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kb58 - 19/8/04 at 02:32 PM

Know where we could see pictures of this? Sounds very impressive... and very expensive. Two dry-sumps?

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sgraber - 19/8/04 at 02:52 PM

quote:

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Originally posted by kb58
Know where we could see pictures of this? Sounds very impressive... and very expensive. Two dry-sumps?

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I did actually once see a photo of this car. But it wasn't a very good angle, all you could see were the two engines... I wish I could remember where I saw it. Some hillclimb page... This was about a year ago.

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BenRelle - 19/8/04 at 03:29 PM

I'll look, but 2 dry sumps shouldn't necessary as the engines were mounted the same orientation as in the bike. I think you're right on the expense side - not a cheap build....

I've had a quick google and nothings coming up. I can't believe that nobody's got a picture. You'll know it, it's a 'clubman' type car, like the one below, and it's burgundy in colour.

http://sports.racer.net/chassis/oms/gallery4.htm

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JoelP - 19/8/04 at 05:01 PM

thanks for the pointer ben, sounds like an ok idea. i take it he used a chain to the crown pinion in the diff, rather than to the flange? mine will have a prop off the flange, and this turned by a pair of longtitudanally mounted enignes via sprocket and chain.

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kb58 - 19/8/04 at 05:10 PM

quote:

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Originally posted by BenRelle
I'll look, but 2 dry sumps shouldn't necessary as the engines were mounted the same orientation as in the bike.

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Except the bike leans, keeping the local "gravity" always straight down, so the oil doesn't slosh from side to side. But in a car.....

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BenRelle - 19/8/04 at 07:37 PM

Not sure I follow your 'gravity' thing, Kurt. If the bike is leant over to one side, and gravity points down, the oil will be on the side of the engine nearest the inside of the turn, won't it? Only looking for where I'm missing something.

OOI, Fisher are using accusump with their latest Blackbird motor'd Fury. They report that they don't need a dry sump with this system.

On the drive for the 2 engined hayabusa car that I can't find pictures for, the engines drove a shaft with a sprocket for each engine on it and a sprocket in the middle that went to one of the chain driven diffs that quaife make for that type of car. Jedi's and OMS's and the like use them.

Cheers,

Ben

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Alan B - 19/8/04 at 08:05 PM

ah but....

gravity pointing down + centrifugal force outwards = ("local gravity"..right KB?)=sloping oil level...approx parallel with sump base...

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kb58 - 19/8/04 at 08:14 PM

Exactly. In a bike the oil will always be very close to parallel to the bottom of the sump (when cornering.) If the bike is leaning it means it is cornering, hence the side force. Gravity is straight down, while the cornering force is straight off to the side. The net force through the oil will always be perpendicular to the pan.

Think of it this way. When you corner on the bike, do you fall off the seat? Is there force throwing you sideways? No, the combined forces push you deeper *straight down* into the seat.


[Edited on 19/8/04 by kb58]

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JoelP - 19/8/04 at 10:01 PM

yup, im with Kurt here. unless the rider is hanging off, the oil will be level. When the rider is off on side, the bike is more upright, but their compined centers of mass combine with the centrifugal (centripedal?) force to balance, but the oil will slosh to perpendicular to the combined centre of mass, rather than just the bikes!

simple, yes?!

NOW GET BACK ON TOPIC YOU GITS!!!!

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Alan B - 20/8/04 at 12:31 PM

Erm...remind me what the topic was...

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JoelP - 20/8/04 at 06:05 PM

ah... good point alan! its been OT for 4 pages!

did i tell anyone about the dead spider i found in my postbox?!

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Alan B - 20/8/04 at 06:09 PM

quote:

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Originally posted by JoelP

did i tell anyone about the dead spider i found in my postbox?!

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Not me....do elaborate....

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JoelP - 20/8/04 at 06:23 PM

it was huge and flat, and the next day it came out stuck to some mail... bloody horrible thing

might i take this opportunity to say that this thread has been very fun, inspiring and... er fun. once this beast is finished and OTR, i shall implement some of these plans.

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Stuart Walker - 20/8/04 at 08:55 PM

Theres no such thing as Centrifugal force.... Centripetal

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kb58 - 20/8/04 at 09:30 PM

I hope that's not Rowan Atkinson's real McLaren!

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JoelP - 20/8/04 at 10:00 PM

quote:

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Originally posted by kb58
I hope that's not Rowan Atkinson's real McLaren!

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well he did write his off, so it could be!

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Stuart Walker - 20/8/04 at 10:43 PM

apparently so...

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kb58 - 21/8/04 at 02:40 PM

Sorry for the thread-jacking...

It's a shame regardless who's McLaren it is. That car is at my #1 position of most impressive cars.

What do you do with something like that, wrecked I mean. I can't imagine you'd just have it towed to the junk yard. I suppose McLaren would buy it back and part it out, or rebuild it at amazing expense.

[Edited on 21/8/04 by kb58]

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James - 29/10/04 at 01:30 PM

quote:

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Originally posted by kb58
I hope that's not Rowan Atkinson's real McLaren!

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Huh? Where did that thread suddenly come from?
Has someone been editing their posts so there's now no mention of it?

Cheers,
James

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James - 29/10/04 at 01:32 PM

quote:

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Originally posted by JoelP

quote:

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Originally posted by kb58
I hope that's not Rowan Atkinson's real McLaren!

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well he did write his off, so it could be!

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Sorry mate but no he didn't.

Drove into back of some old dear in a mini IIRC. Mini was flipped, Mclaren was damaged but repairable I believe.

James

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phelpsa - 29/10/04 at 01:47 PM

We were parked next to his purple mclaren in my old school, as I was playing against his son's team at Rugby.

It was very shiny, but obviously used often and hard (quite dirty and Tyres virtually bald on the rear). This was in july.

Adam

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phelpsa - 29/10/04 at 01:50 PM

quote:

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Originally posted by BenRelle
You might want to get down to the Brighton speed trials later this year. Last year there was a twin 'busa engined car with a mid mounted config driving rear wheels. He had both the engines driving a common shaft via their normal sprocket and chains, and then another sprocket and chain to the diff and so to the wheels. It was an awesome machine. From the look of that car and the times it posted, you won't need those turbos.

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I've sat in this car at Gurston Down hillclimb. It wasn't very reliable (kept stalling).

Adam

[Edited on 29/10/04 by phelpsa]

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Ratman - 9/11/04 at 03:04 AM

quote:

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Originally posted by alister667
...they have the engine basically where the passenger sits, ...!

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I am keen to try this with a two seater. I have built a two seater go-kart that has the engine alongside the driver. I thought to just grow this one a bit and use a 1200cc V-twin bike engine (or bigger) for a road goer. I had planned to make the seating slightly tandem, with the passenger's seat about 500mm rearward to the driver, so the cockpit can be made a bit narrower. Honda have a "side-by-side" track car done in a similar fashion. It looks very cute. I'll post a link here if I can find it. Cheers, Brian
http://world.honda.com/news/1997/c970919b.html

[Edited on 9/11/04 by Ratman]

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kb58 - 9/11/04 at 04:37 AM

Sportbike engine in a kart? Here:

http://www.kimini.com/Video/gixxerkart_video.wmv

I don't like the music, but you get the idea how over the top it is...


[Edited on 11/9/04 by kb58]

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