Board logo

Trike Build Update... Again, All Thoughts Welcome.
scootz - 25/6/11 at 11:16 AM

My last trike-build thread meandered about a bit as I changed direction more often than I changed my under-crackers (which is once a week for those with an interest in these things... and that's whether they need changing or not).

I started with a Formula Rolon single seater with an Aprilia engine and Hayabusa rear-end. Then I moved onto a BMW K1200 engine and R1200 rear-end. Then I sold the lot and bought a Swift DB1 single-seater and another Aprilia engine. And now they are going to be sold as I have (hopefully) settled on a master-plan and neither figures in it!

Anyway, I now have this:







It's a carbon-fibre single-seater monocoque that was designed for use in Formula Vee. Unfortunately the regs were changed and CF chassis were banned. Their loss... my gain!

This is what a finished car looked like (minus the nosecone / rear cover):



Like all Vee's, the running gear came from the VW Beetle. The front uses the H-Beam assy (the finished race-car had a fairly trick set-up):





Despite being as old as the hills, I plan to stick with a Beetle beam as the car was designed for one, they're as strong as an ox, easily maintained and relatively cheap. I also see that some US companies do ali beams for lightweight baja-bugs, so that would hopefully deal with the weight penalty.

The rear bulkhead has an ali honeycomb insert between the CF layers to provide extra strength. I'm thinking that my rear subframe will attach via top-hat inserts (so as not to crush the CF / ali honeycomb panel) and clevis-mounts. This is similar to how the VW engine was hung on the race-car:



Engine!? I always wanted to use a BMW Boxer twin as it lends itself to a simple installation (no radiator / plumbing), they're light (and that weight is all low-down), and it has a shaft-drive (low maintenance). That said, the 60-100bhp figures were rather underwhelming. So I searched high and low for the 120bhp R1200S engine only to find that they're few and far between and when one did pop-up, the prices were just ridiculous. And then came a miracle, not an R1200S lump for sale, but the holiest of holy's... the even more elusive HP2 Sport engine! What's more, it was sensibly priced! Get-in... 130bhp, 85ft/lbs and only 45kg! Game-on!



Like last time, I guess plenty of you will be wondering why am I taking a 4-wheeled race-car and making it into a trike? Firstly, I want something 'different', secondly, whatever I have must be road legal and whilst I would love to IVA a single-seater race-car, the test is just too restrictive. A trike comes under MSVA regulations and the test is comparatively simple (particularly the emissions regs).

I've done a conservative guesstimate of weights involved and it will comfortably come in under 300kg. Hopefully, as low as 260kg so I can hit the 500bhp per ton mark.

It's unlikely I'll get the thing on the road before the bad weather comes in, but I'd be sorely disappointed if it's not finished this year.

All thoughts / opinions welcome!


v8kid - 25/6/11 at 11:49 AM

Now you are really on the right track! Looks like this idea is a real go-er.

Light, easy to get high front roll stiffness, easy engine install. You will need to watch wheelbase don't get too long but I'm sure you will overcome that.

Keep us informed of the progress - I'd like to pop over to see it sometime when I'm not press-ganged on the boat!

Cheers!


scootz - 25/6/11 at 12:11 PM

Cheers David.

I'll give you a shout when the front and back has been joined together and it's back up the road.


blakep82 - 25/6/11 at 12:14 PM

what happened to the windle chassis/frame then?


scootz - 25/6/11 at 12:20 PM

Windle have the Swift frame just now, but we worked out that by the time they did the necessary work (particularly widening it for my fat ass... sorry, manly shoulders!), then it would be better to just change it over for a chassis in which I already fit!

They will be getting the CF tub down early next week and will still be doing the engine subframe work.

PS - if anyone is looking for good fabricators, then I can't praise Windle's workmanship highly enough. Good lads too.


blakep82 - 25/6/11 at 12:25 PM

i'd love one of their F1 chassis lol
when i u2u'd u a while back i thought it was all being done by them already, that was a few months ago now, but i hope it works out this time!


scootz - 25/6/11 at 12:32 PM

I'm in a queue and they're busy!

Not a problem though as I made it clear when I asked them to do the work that there was no rush on my part. I figured they will have their core-customers who need quick service to go racing, so as far as I'm concerned they should deal with their needs first and then fit my weird little project in when it suits. TBH, I'm glad of the wait as I'd have been kicking myself if it was all built on the Swift chassis and then the CF tub and HP2 engine popped-up for sale!


TheGiantTribble - 25/6/11 at 12:56 PM

WOW that's going to be fast
500 horses per tonne....sounds a blast
But with only three contact patchs are you going to get as much smile/cornering performance as you would if you leave it as a four wheeler?


Humbug - 25/6/11 at 01:03 PM

Looks like a winner! Keep us updated on progress

btw, the picture of the c/f tub in the first pic (without many scale references) makes it look like a lightweight prop tunnel/centre console


ceebmoj - 27/6/11 at 12:11 PM

As other have said looks like a very interesting project keep us up to date with the progress.

also with out wanting to be crass how much was the tub. I ask because its such a lovely thing to look at I would put one on the wall.


scootz - 29/6/11 at 04:04 PM

Cheers guys!


scootz - 29/6/11 at 04:05 PM

quote:
Originally posted by ceebmoj
also with out wanting to be crass how much was the tub. I ask because its such a lovely thing to look at I would put one on the wall.


Not cheap, but not as much as you would think.


scootz - 29/6/11 at 04:15 PM

Just back from a trip down south to fetch the Beemer engine (Leicestershire, then Nottinghamshire to drop it off and then back to East Lothian). Been on the road since 4am... knackered.com!

Got to sit in the carbon tub and make 'broom-broom' noises! Loads of room in there... even for an adonis like me!

Not had a chance to weigh it yet, but I can lift it with one hand!

First time I've seen all the bits together and I'm really pleased. The engine may be an airhead, but it sure looks swish!





scootz - 1/7/11 at 05:33 PM

Got my rear shock and brake caliper today!




Kwik - 1/7/11 at 09:12 PM

just...

this will be amazing... what are you going to do about a roll hoop though, you are missing a wheel remember

[Edited on 1/7/11 by Kwik]


scootz - 1/7/11 at 09:35 PM

Cheers!

There are ali honeycomb panels sandwiched between most of the CF layers in the back-end to add strength and rigidity. The roll hoop bolts through one of these.


russbost - 1/7/11 at 10:09 PM

First dibs when you change your mind!


scootz - 2/7/11 at 10:57 AM

quote:
Originally posted by russbost
First dibs when you change your mind!




I'm keeping it!


scootz - 16/7/11 at 05:43 PM

Thinking about the roll-hoop assy.

I'm going to have a stainless plate with a T45 hoop welded onto it. Can anyone suggest a thickness for the plate and a wall thickness for the hoop?





The plate will be fitted using 8 bolts (yellow dots) and 2 harness bolts (red dots).



alistairolsen - 17/7/11 at 09:49 AM

either 45x2.5mm or 50x2mm as recommended by the MSA.

I wouldnt use stainless for the plate and have a mixed metal weld on the base of my roll bar hoops either, do it all in steel and powercoat it.


eddie99 - 17/7/11 at 09:50 AM

Definitely does look good, second dibs when both you and Russ change your mind


T66 - 17/7/11 at 11:21 AM

I knew once you had sent me the picture of the tub , you were wavering on the other chassis.



Its a valid point avoiding all the Windle Welding, its going to look (and go) very well Scott.....






matt_gsxr - 17/7/11 at 11:56 AM

Why not duplicate the lovely CF thing in your previous photo?



Steve Hignett - 17/7/11 at 12:29 PM

quote:
Originally posted by matt_gsxr
Why not duplicate the lovely CF thing in your previous photo?

It wouldn't be a 2 second job, but it could be done


scootz - 17/7/11 at 04:15 PM

I could, but I want it road-registered and IVA would be a PITA!!!

Besides, I want something completely different, so 3 wheels it is!


scootz - 17/7/11 at 04:18 PM

quote:
Originally posted by T66
Its a valid point avoiding all the Windle Welding, its going to look (and go) very well Scott.....



Yup, the fabrication work to get the Swift chassis triked would have been mega-expensive.


Minicooper - 18/7/11 at 10:22 AM

quote:
Originally posted by scootz
Thinking about the roll-hoop assy.

I'm going to have a stainless plate with a T45 hoop welded onto it. Can anyone suggest a thickness for the plate and a wall thickness for the hoop?





The plate will be fitted using 8 bolts (yellow dots) and 2 harness bolts (red dots).





You have may of already mentioned it, but is there any bracing of any sort? If not or it's not possible, how about running the main hoop legs through the plate and brace them lower down on the vertical

Cheers
David


scootz - 18/7/11 at 10:26 AM

Hi David

There are aluminium honeycomb panels sandwiched between the CF in various parts of the chassis (mainly front / rear).

These provide the strength for mounting points, roll hoop, etc.


Sam_68 - 18/7/11 at 06:40 PM

quote:
Originally posted by scootz
Hi David

There are aluminium honeycomb panels sandwiched between the CF in various parts of the chassis (mainly front / rear).

These provide the strength for mounting points, roll hoop, etc.


You mean solid aluminium hard-points/plates sandwiched between the CF, hopefully? Honeycomb isn't strong enough to bolt anything to!?

The other solution is to use threaded 'top hat' inserts that are screwed-and-bonded into one another from either side of the honeycomb panel, allowing you to bolt on steel brackets/flitch plates. The advantage here is that you can add them later (if you know what you're doing and ensure that the loads are spread across a sufficient skin area on the panel), whereas moulded-in hardpoints obviously have to be moulded in at the outset. This pic shows an example (actually a front suspension mounting bracket, but you get the idea):




Rather than using a big, flat steel plate to mount your roll bars and harness to, as you show on your photographs above, you'd be better using smaller angled plates that wrap around the corners of the monocoque; that way, no matter what the direction of the loading, you'll ensure that it is fed into the carbon fibre skin in shear (good) rather than tension/compression (bad). The photo below should hopefully illustrate what I mean. 1/8" thick steel should be more than adequate if you design it correctly, though the roll bar on the car in the photo is actually aluminium, for lightness:





[Edited on 18/7/11 by Sam_68]


Uphill Racer - 19/7/11 at 12:29 AM

I agree with Sam regarding hard points.
Ian Scott ran the roll hoop down the back of one of his carbon tubs plated to the side too. The rear sub frame hung off of it as well. If your hard points are in the tub as in your pics I would use them to do both jobs at once.


scootz - 19/7/11 at 06:28 AM

Cheers fellas.

I'll take some screen shots of the cad drawings showing the hard points. IIRC, they are 'L' shaped to connect vertical faces to horizontal faces.


scootz - 19/7/11 at 06:49 AM

CHASSIS CAD DRAWING - SIDE PROFILE

Inserts are in purple...





scootz - 19/7/11 at 06:52 AM

CHASSIS CAD DRAWING - REAR BULKHEAD

Inserts are in purple...






DRAWINGS OF MOUNTING HARDWARE

Mainly clevis style...






ENGINE AS HUNG ON ORIGINAL FORMULA VEE



scootz - 19/7/11 at 06:56 AM

CHASSIS CAD DRAWING - FRONT PROFILE

Inserts are in purple...





FRONT AXLE AS HUNG ON ORIGINAL FORMULA VEE

I won't be running the trike anywhere near as low as the race-cars, so plan to shift the torsion-beams down a few inches so all mounting points are flat to the face of the front bulkhead.



scootz - 19/7/11 at 07:03 AM

CAD DRAWING OF ROLL-HOOP

This was the roll-hoop as used on the race car. It was approved by the regulatory body. Note that it bolts directly onto the chassis from underneath the top-chassis panel.



matt_gsxr - 3/9/11 at 11:07 PM

I just noticed that there were a couple of tubs that look (to me) identical to that which scootz is building up.

These are advertised as new in http://www.trackdriver.com/

http://www.motorsportads.com/race-cars/single-seaters/21521.html

Just thought it might be useful for someone who wants to go down the same route as Scootz (but hasn't got the time to wait for him to sell-up )

Matt


scootz - 4/9/11 at 09:10 AM

Yup... that's the same one. He's cut and paste his old advert though and there's actually only one left. I thought about buying the two of them in case I had an accident with one, but the funds just wouldn't allow.


scootz - 8/10/11 at 10:19 PM

Latest progress:






HowardB - 9/10/11 at 05:02 AM

wow! Would the bmw engine make a good BEC?


scootz - 9/10/11 at 02:49 PM

quote:
Originally posted by HowardB
wow! Would the bmw engine make a good BEC?


Not really Howard. The BMW engines need to have their cylinders out in the airflow (air-cooled), they're not very powerful at 110bhp (typically), and they tend to be expensive.

The HP2 Sport engine that I'm using is a step above the normal BMW 1200 boxer-twin (it has fancy internals and has been ported and polished to within an inch of its life at the factory). It should hit 140bhp with a good airbox, exhaust and mapping, so plenty powerful for a sub-300kg (hopefully) reverse-trike! Unfortunately they are like hens-teeth and fetch around £3k for a complete one (with gearbox). I lucked-in when I found mine at the time I did... and the price I was offered! It's not often that happens to me


ceebmoj - 9/10/11 at 06:33 PM

Some nice, fabrication there cant weight to see the progress.


T66 - 9/10/11 at 07:15 PM

Scott - You need to give the guys at Mansfield a big up , not for the smoked trout ,chips & hospitality, but their big big talent with bits of tubing and a welder.


Chips are on me next time round, and if they want an apprentice tx me.


HowardB - 9/10/11 at 08:48 PM

quote:
Originally posted by scootz
quote:
Originally posted by HowardB
wow! Would the bmw engine make a good BEC?


Not really Howard. The BMW engines need to have their cylinders out in the airflow (air-cooled), they're not very powerful at 110bhp (typically), and they tend to be expensive.

The HP2 Sport engine that I'm using is a step above the normal BMW 1200 boxer-twin (it has fancy internals and has been ported and polished to within an inch of its life at the factory). It should hit 140bhp with a good airbox, exhaust and mapping, so plenty powerful for a sub-300kg (hopefully) reverse-trike! Unfortunately they are like hens-teeth and fetch around £3k for a complete one (with gearbox). I lucked-in when I found mine at the time I did... and the price I was offered! It's not often that happens to me


Was just interested to see, I guess it looked interesting, but as you say is not the best option, but looks awesome on your kit!! Look forward to seeing it when it's complete,..


scootz - 9/10/11 at 08:56 PM

quote:
Originally posted by T66
Scott - You need to give the guys at Mansfield a big up...


Thats coming!


welderman - 10/10/11 at 07:54 AM

I must say it's looking very good there mister


scootz - 10/10/11 at 11:20 AM

Cheers fella... how's the pro-turbo-blade-comp thing coming on?


kipper - 10/10/11 at 11:32 AM

WOW, looking great Skootz, makes mine look like a HGV
Denis.


welderman - 10/10/11 at 11:42 AM

quote:
Originally posted by scootz
Cheers fella... how's the pro-turbo-blade-comp thing coming on?


Comin on a little. Brake lines next


scootz - 10/10/11 at 06:40 PM

quote:
Originally posted by welderman
quote:
Originally posted by scootz
Cheers fella... how's the pro-turbo-blade-comp thing coming on?


Comin on a little. Brake lines next


Which silly bugger took them off in the first place!?


scootz - 10/10/11 at 06:40 PM



MikeCapon - 10/10/11 at 06:53 PM

Well Scootz, the blunt end looks excellent.

What are your plans for the pointy end?


scootz - 10/10/11 at 07:28 PM

I'm betwixt and between!

I've been wondering if it would be possible to make a front-subframe to attach to the face of the front bulkhead. Then use top rockers like the FVL type and have the dampers inboard...



The bottom would be a similar design to the top rocker, but cut at the red line...



I'm worried that I'd be putting too much stress through the rockers and the front-subframe though as I see that the FVL car uses a traditional wishbone on the bottom.



Mind you, that might just be because they didn't want to use another heavy arm on the bottom!!!??? As always... all thoughts welcome!

Also worth noting that the trike will weigh less than half of a FVL at 275-ish kg and wouldn't be subject to the same punishment.


clairetoo - 10/10/11 at 07:42 PM

Well , most of JP's cars (Fury , Striker etc) use a very similar top wishbone so I dont see a problem there - maybe a reversed Sylva-style lower `bone , and take the loads from in front of the axle line ?
If anyone can draw a Fury suspension setup with the lower `bones reversed this would make sense......?


scootz - 10/10/11 at 07:45 PM

Cheers Claire... I'm off to google some Sylvas!


Proby - 10/10/11 at 07:47 PM

Scootz,

I've never been a fan of trikes, but this has got me interested. Looks a great project and can't wait to see it progressing further. Well done!


scootz - 10/10/11 at 07:48 PM

Found a pic... makes perfect sense! Ta!


Sam_68 - 11/10/11 at 05:41 AM

quote:
Originally posted by scootzMind you, that might just be because they didn't want to use another heavy arm on the bottom!!!??? As always... all thoughts welcome!


Yep, the only reason FVL and other rocker-arm suspensions use a 'traditional' wishbone on the bottom is simply 'cos they don't need to take the big bending loads of the upper rocker (there's no spring resisting the movement of the bottom wishbone), so there's no point making it any heavier than it needs to be.


scootz - 11/10/11 at 05:45 PM

Cheers!

Sounds like it might be a go-er then!

I get the chassis back up the road on Friday, so I can see what's possible with the space available.


Sam_68 - 11/10/11 at 06:27 PM

One thing to watch if you're intending to use a bottom wishbone that resembles the top 'rocking' wishbone:

You'll notice that the conventional bottom wisbones on most rocker set-ups have a much wider 'base' (ie the distance between the fore and aft chassis pick-ups is much greater than the length of the rocker shaft on the top rocker wishbone). This is to make them stiff enough and stable enough to resist braking loads.

Rocker arm suspension designs that don't have adequate fore-aft stiffness can have problems with distortion under braking that causes judder and weaving and all sorts of nasty side-effects.

Admittedly, we're usually talking about slick-shod single-seat racing cars, but you might want to take care that the length of the rocker shaft is enough to impart plent of stiffness, just to be on the safe side.


Triton - 17/10/11 at 09:07 AM

Hey Scootz any more pictures?


scootz - 17/10/11 at 09:11 AM

Nothing new to report just now Triton.

I'm just trying to get the back end finished completely before starting on the front.


Triton - 17/10/11 at 11:09 AM

Okey doke I will keep coming back to look then.. It's got to be the best thing I have seen in ages


scootz - 25/10/11 at 03:09 PM

Back home... and gathering dust until the bank balance recovers!



scootz - 2/11/11 at 05:36 PM

I'm not liking the K1200 wheel that you see in the pictures (it runs the wrong way), so am on the lookout for a new rear.

Whilst I would love to get an HP2 Sport forged rear, I just can't afford the £900 it will cost.

I've a feeling that shiny spoked wheels would be a nice contrast... what do we think?




l0rd - 2/11/11 at 06:16 PM

Nope

I don't think it will look right


scootz - 2/11/11 at 06:16 PM

So you're undecided then!?


HowardB - 2/11/11 at 06:29 PM

in my humble opinion it needs a big flat topped car tyre on a matt black 3 spoke on the rear, hope that's not too specific for you.



can't wait to see it running!


franky - 2/11/11 at 06:52 PM

I agree, it looks aweful. it'll weight 10000000.5kg too.


scootz - 2/11/11 at 06:53 PM

Let's can that idea then!!!!


TheGiantTribble - 2/11/11 at 10:45 PM

Don't can it.
I like the shinny spiky wheel idea.
Kinda a olde meets new theme thingy going on

I'll shut up now :)


kipper - 3/11/11 at 08:00 AM

Hi Scootz.
I think the spoked wheel would look wrong alongside the carbon tub, for my tuppence worth it needs a car type rim with a flat treaded tyre.
Denis.


lewis - 3/11/11 at 08:16 AM

i quite like the wheel you have fitted,will look like a cutting wheel going round


scootz - 3/11/11 at 08:44 AM

Cheers guys... whatever wheel I go for will get a car tyre in the long term.

I'll use the bike tyre (it is pretty new) that came with that wheel for the MSVA and the odd few miles it takes for me to destroy it!


scootz - 3/11/11 at 08:45 AM

quote:
Originally posted by lewis
i quite like the wheel you have fitted,will look like a cutting wheel going round


I know what you mean, but I think it would look 'faster' if it was going the right way round


scootz - 12/11/11 at 05:03 PM

LOL... I've done a complete 360!!! I'm now liking the BMW wheel spinning the 'wrong' way! ... that's that sorted then!

I'm also getting quite fond of the black / yellow contrast as it stands just now! Think I may powder-coat the frame and 3 wheels to match the yellow nose-cone!


scootz - 12/11/11 at 05:12 PM

Been thinking of instrumentation and switches. As I've already mentioned a dozen times - the cockpit is tight!!!



It looks in the photo as if there is sufficient mounting space on the panel behind the steering wheel for the display / controls. Unfortunately it's just an illusion - there is no space!

Sooooo, was thinking of putting the switches on the steering wheel, and the display / tell-tale lights on the 'lip' at the front edge of the cockpit...



The blue oval being the display (wired to also act as the position light tell-tale).
The green circles either side being the indicator / hazard tell-tales.

On the wheel:
The two green circles being the indicator switches.
Red oval being the hazard switch.
Yellow oval being the dip / main switch.
Blue oval being the horn switch.


scootz - 11/2/12 at 01:00 PM

Still skint, so no progress

Lots of thinking going on though... mainly about the front-end (still)... and most of it nuts!

The main problem with building a front-subframe to take double wishbones (in my circumstances) is that the wishbones would need to be narrow, and they would have to be pretty long to make the 'magic' 1:6 ratio.

The other issue is that they would have to be shaped something like the following pic so that the wheels weren't sitting right at the front end of the vehicle (it would make the wheelbase / track insanely long and would look awful).



I'm thinking that such a long / narrow wishbone would have to be made of kryptonite or cast iron to prevent it flexing (snapping!) under load??? Can anyone offer any opinions?

I think I previously mentioned that a Formula Vauxhall Lotus uses an upper wishbone that's about the required shape, but it would need the rocker 'section' cut-off as I couldn't go inboard with the shocks and I would need to use them for top AND bottom of the trike...



But would 4 of these last long???

Or could I abandon the 1:6 theory altogether and fit two (very) wide wheels (F1 stylee) up front on short stubby wishbones (narrowing the track) with LOTS of travel, so that the machine leaned lots in corners, but still retained a large rubber contact patch on the outside wheel???



All thought welcome... particularly those suggesting that I should step away from the computer and never think about designing my own build EVER again!


Sam_68 - 11/2/12 at 01:56 PM

Do a Google Images search for 'Frank Costin Protos'.

The Protos suffered big problems with judder under braking, due to the raked suspension arms flexing, and I believe they later fitted additional radius arms to cure the problem, but to be fair that was a slick tyred racing car under racing conditions with a top-notch professional driver: Costin himself reported that he couldn't replicate the problem when he drove the car, 'cos he couldn't drive it hard enough.

But as I've suggested previously on this thread, I think you're getting too hung up on retaining the existing 'hard points' on your tub: it's really not that difficult to bond in additional hard points for the suspension wherever you want them, if you know what you're doing.


scootz - 11/2/12 at 02:45 PM

That's the problem Sam... I don't know what I'm doing, and it seems it will be big bucks to get someone who knows what they're doing to do it!!!

I spoke to a few CF tub makers about it and they recommended making a bulkhead in the region of where my knees will be in the car. (Motorsport Industry) cost = £thousands£.

Will check out the example you raised.


scootz - 11/2/12 at 02:53 PM

Yup... that's the type of wishbone I envisage - but it would need to be top AND bottom.



Unless I could bond a simple metal strut across the ali-honeycomb floor panel at the knee area that could incorporate the left and right rear-most lower wishbone locating points (the forward ones being clevis type mounts attached to the face of the footwell bulkhead)???


Neville Jones - 12/2/12 at 11:07 AM

Stick a USA hotrod type beam axle across the front, with trailing radius rods back to the tub. Single leaf steel spring mounted to the tub front. Job done! And you can get the thing on the road and having fun.

99% 0f people wouldn't know or feel the difference on the road, to the fancy and complicated setup you're thinking about. And does it really matter?

Cheers,
Nev.


Sam_68 - 12/2/12 at 11:22 AM

quote:
Originally posted by Neville Jones
Stick a USA hotrod type beam axle across the front, with trailing radius rods back to the tub.


Part of the problem as I understand it, though, is that Scootz is cautious of providing additional hard-points for suspension pick-ups .... and the radius rods would need such pick ups.

quote:
Originally posted by Neville Jones
99% 0f people wouldn't know or feel the difference on the road.


Hmmm... not sure I agree with that; I've driven a number of beam axle cars (from vintage sports cars to my workhorse Range Rover) and there's a very distinctive feel to them: no matter how well located and damped they are, there's a distinctive 'shimmy' to the feedback you get through the wheel when you hit bumps at speed, due to the gyroscopic forces.

But in any event, if you're satisfied with the compromises of a beam axle instead of tricksy double wishbones then well set-up trailing arms are really no worse (just a different set of compromises), so the sensible solution would be to bolt on the suspension that the tub was designed for in the first place.


scootz - 12/2/12 at 11:34 AM

Thanks again Nev and Sam... your input(s) are much appreciated!

Would I find the handling characteristics of a trailing-arm beam-style set-up to be a problem... probably not!

This piece explains the handling peculiarities for those who are not familiar with it...



The dune-buggy guys have some pretty neat beams with top and bottom thru-rods instead of torsion leafs, and control the arms movement through coil over shocks. I guess I could arrange for a MUCH more discreet and MSVA friendly shock tower to be fabricated and welded to the beam as I only need a fraction of the travel they require.


Sam_68 - 12/2/12 at 11:45 AM

quote:
Originally posted by scootzUnless I could bond a simple metal strut across the ali-honeycomb floor panel at the knee area that could incorporate the left and right rear-most lower wishbone locating points (the forward ones being clevis type mounts attached to the face of the footwell bulkhead)???


As with the roll bar mounts, ideally you want to arrange the way the loads are fed into the monocoque by wrapping them round the corner at the lower edge of the tub, so that you have stiffness in two planes.

Honestly, it's nothing to be scared of - if you don't have access to the necessary software for the FEA, just make sure it's over-engineered, same as most 'Locost' spaceframe projects!

If I get chance, I'll sketch something up tomorrow when I have access to a scanner to post the results, but if I forget, give me a prod though u2u.


Sam_68 - 12/2/12 at 11:48 AM

quote:
Originally posted by scootzThis piece explains the handling peculiarities for those who are not familiar with it...



At risk of stating the obvious, having a system where the front-end grip falls off as roll builds up is not necessarily a problem for a reverse trike.... better that than the other way around!


scootz - 12/2/12 at 12:18 PM

Good point!

Would mighty obliged if you could scribble something down - I find it hard to visualise sometimes.

Thanks again.


Sam_68 - 13/2/12 at 07:51 PM

Fag-packet sketch of a section through the lower corner of your tub (eg. to mount a lower wishbone pick-up) as an example:



The 'top hat' section inserts theaded into each other from either side of the panel and bonded into place with epoxy are the key: you can use these to bolt through/into to mount pretty much whatever bracketry you want to, with a bit of ingenuity (bolts not shown on this sketch 'cos I was too lazy to draw them, but you get the idea?).

Refer back to my earlier photo of the FW400's damper and wishbone mounting brackets to see the sort of thing that can be achieved in practice.


scootz - 13/2/12 at 08:01 PM

Thanks for that Sam. I'm building a better picture in my head of what's possible.


scootz - 22/2/12 at 09:59 AM

Did some measuring and the wheelbase is going to be 293cm. So, I'm looking at a track width around 183cm.


ceebmoj - 22/2/12 at 10:39 AM

I know its not the Scootz way but in the first post you have a picture that shows the set up that others use on this car what's wrong with that? I thought it looked neat and far more compact than I expected it to be.

[Edited on 22/2/12 by ceebmoj]


scootz - 22/2/12 at 12:43 PM

quote:
Originally posted by ceebmoj
I know its not the Scootz way but in the first post you have a picture that shows the set up that others use on this car what's wrong with that? I thought it looked neat and far more compact than I expected it to be.



It is fairly neat, but the VW beam is considered a little antiquated.


ceebmoj - 22/2/12 at 03:53 PM

quote:
Originally posted by scootz
quote:
Originally posted by ceebmoj
I know its not the Scootz way but in the first post you have a picture that shows the set up that others use on this car what's wrong with that? I thought it looked neat and far more compact than I expected it to be.



It is fairly neat, but the VW beam is considered a little antiquated.


I agree, but the tub was designed to take it.


maccmike - 29/2/12 at 05:40 PM

thats awesome and stunning, would love to see it in flesh when its built


maccmike - 3/6/12 at 03:50 AM

any updates?


scootz - 3/6/12 at 09:03 AM

Not really... I've gone full circle a couple of times on the front suspension design, and I'm currently back working on a Beetle style beam for it.

The beam I'm building is 6-inches longer than a standard VW one to give me an increased track-width for stability. I won't be using torsion leafs springs... instead I'm running a 0.750" 4130 anti-roll bar through the bottom axle tube to eliminate as much body-roll as is comfortable (body roll is particularly unwelcome on a beam style front axle as it promotes positive camber).

I'll use coilover shocks mounted between the lower trailing arm and upper beam tube and put a tie rod through the top tube to hold the arms in place.

I'll hopefully have the beam tack-welded together later in the week, so will fire up a few pics when it's ready.


maccmike - 3/6/12 at 11:50 AM

luck forward to it


JC - 30/12/12 at 09:04 AM

Scootz, have you seen this? Links not cheap, but would be a simple bolt on?


scootz - 30/12/12 at 11:39 AM

Cheers JC.

I've been meaning to have a look at the Red Design unit in the flesh for sometime.


scootz - 12/2/13 at 02:33 AM

Bad news... Decided that the VW front end is too much of a compromise, so I'm abandoning the Formula Vee tub.

Good news... I have the whole front end from a Dallara F396 arriving next weekend! Still full of carbon tub goodness and comes complete with roll-bar, steering, pedals, tank and (insert fanfare)... double wishbone suspension!


T66 - 12/2/13 at 03:26 AM

Go to bed....


scootz - 12/2/13 at 03:30 AM

Don't think the docs would appreciate that Ivo. I'm nightshift.


scootz - 12/2/13 at 06:51 AM

A Dallara F396...



snakebelly - 12/2/13 at 08:25 PM

So what's the price of the formula v tub then £150?
:-)


scootz - 12/2/13 at 08:48 PM

£150? Fraid not (but good try ).

I'd need at least a grand for the tub and nose cone.


Sam_68 - 13/2/13 at 01:19 PM

quote:
Originally posted by scootz
A Dallara F396...




Is that monoshock at the front, Scootz?

You appreciate, I hope, that the very long swing axle lengths that are typical of the double wishbone set-ups on wings-and-slicks single seaters actually give not dissimilar geometry (ie. near equivalency of camber to roll angle) to the 'antiquated' VW front trailing arm set-up you've just abandoned?!


scootz - 13/2/13 at 02:24 PM

Yup... monoshock, but I have thew scope to change it to twin-shocks if needs must.


zilspeed - 14/2/13 at 05:44 PM

You have mail etc, re tub.


scootz - 19/2/13 at 12:19 PM

Dallara bits arrived on Sunday. All in pretty good nick, but will still need a little cosmetic TLC.

I'll not get a chance to get going until after I've cleared out th garage properly (and raised some pennies).

On a side note... what a nice bloke Dermot Healy is. I've bought stuff from him in the past, but never met him until Sunday. Very fair, sensible minded and helpful. Highly recommended! :-)


scootz - 21/2/13 at 08:44 AM

Been thinking about the pedal box...

I knew it would be tight, but by god you would need pixie sized feet to be able to use all the pedals cleanly! My size 11's will struggle even with tight race boots.

So... I'm exporting the possibility of keeping the gas and brake pedals down there only, and going for a hand clutch (converting a bike's clutch lever / mc assy to become a dash mounted jobbie).

I'll be running a klicktonic style shifter with up / down blipper, so I should (theoretically) only need to use it for starting and stopping.

Anyone converted a bike clutch lever to a paddle???


ceebmoj - 22/3/13 at 08:57 PM

quote:
Originally posted by scootz
On a side note... what a nice bloke Dermot Healy is. I've bought stuff from him in the past, but never met him until Sunday. Very fair, sensible minded and helpful. Highly recommended! :-)


He is a top bloke. But don't ever go to his house, or lock up. He has so much cool stuff for sale.


scootz - 22/3/13 at 08:57 PM


scootz - 4/4/13 at 07:17 PM

The Rocket engine turned up the other day. It's a big old lump!

Not weighed it myself yet to see if Triumphs claim of 82kg is right enough, but it certainly did't feel as heavy as it looked when we lifted it off the couriers van.

It's dry-dumped so no worries about sump-oil splashing around in directions it was never meant to endure
It has a feather-light cable clutch, so the hand-clutch idea is now super-simple(-ish).
It has double-butterfly throttle bodies, so will be junking the lower ones (the top ones have the TPS on them).

Each piston measures 4-inches across (the same size as those found in a Dodge Viper ).
Apparently (and we'll find out in the fullness of time ), a revised intake, a free-flowing exhaust and a properly set-up aftermarket ECU should see it reaching 180-190bhp and the 180-90 ft/lbs of torque. Plenty of 'go' for a 300-35kg vehicle!

Re-profiled cams (no one sells an aftermarket set ), and headwork should see that rise to 210bhp, and adding a set of high-comp pistons sees it stretch to 240. Maybe something for the future, but no need at this stage!


scootz - 11/4/13 at 08:59 PM

Not done much... just removed the secondary butterflies from the TB's and mocked-up the layout.






ceebmoj - 11/4/13 at 09:06 PM

Sticking with 3 wheels?


Are you going to get the same guys who made the last engine cradle to do this one it looked relay good.


scootz - 11/4/13 at 09:12 PM

Yep... 3 wheels (for no other reason than it's so much easier to MSVA a trike than IVA a car).

I've tried calling Windle, but it's ringing out. I'm also struggling to find them online, so not sure of they are still trading (be a real shame if not, because they are absolutely top-notch!).

I wonder if Andy B would be interested (when he ever finds a quiet spell!).


femster87 - 11/4/13 at 09:25 PM

I see you have cleaned up the garage


scootz - 11/4/13 at 09:51 PM

I was so embarrassed after you visited Femi that I had a mass tidy!

PS - I have a quote of £110 from Shiply... £55 each???


femster87 - 11/4/13 at 10:00 PM

very fair price. Just for the tub?


scootz - 11/4/13 at 10:07 PM

And the bodywork. I'd be inclined to let the Shiply listing continue for another few days t see if that price comes down.


femster87 - 11/4/13 at 10:10 PM

Ok just keep me posted. Dallara is looking tidy


ceebmoj - 15/5/13 at 09:22 PM

have you seen

kit car/ bike/ hayabusa engine only very low miles | eBay


Uphill Racer - 15/5/13 at 10:29 PM

quote:
Originally posted by scootz
Anyone converted a bike clutch lever to a paddle???


I saw this some years ago and thought it was a nice solution, electricery was used via a paddle operating a potentiometer through a weak spring mimicking the clutch lever action.

[IMG]http://i72.photobucket.com/albums/i187/uphill-racer/DSCF0020A.jpg[/IMG ]

[Edited on 15/5/13 by Uphill Racer]