Post by: Mark Underdown on 31 Oct 20, 06:42 pm
Just checked out some of the cars suggested and found a Frazier Nash that looks interesting.
Front axle and suspension would be an interesting challenge!
Post by: Marek.Z.N on 31 Oct 20, 10:17 pm
Post by: StefanN on 31 Oct 20, 11:13 pm
Post by: RhysN on 01 Nov 20, 10:55 am
Post by: Mark Underdown on 01 Nov 20, 04:18 pm
The second problem is scaling it off, I haven't got any wheels yet, Honda wheels seem popular and I took a guess at the outside diameter of these being 530mm and then scaled the picture/drawing to suit.
Could anyone confirm the outside diameter of a 17 inch Honda tyre.
Based on the 530mm OD wheel, it gives a wheel base of 1880mm is this about right?
Thanks.
Post by: RhysN on 01 Nov 20, 05:16 pm
Post by: StefanN on 01 Nov 20, 05:53 pm
Here's some thoughts in case they're helpful:
As Rhys says, remember to leave enough space for a full-size person when scaling.
Get your body weight low and forward - to that end you can push the front of the ck body forward without losing the look and compress the scuttle (Bill's trick).
Don't make the cockpit too wide - sitting in other people's ck's will give you the best feel for that.
Think about the packaging of pedals and steering when planning your body construction - it can end up quite busy at that end!
Post by: Mark Underdown on 01 Nov 20, 07:24 pm
Although the cars are not exact replicas, I really need to draw something up before I start cutting metal. I have found with other projects if I don't have a decent plan I spend ages in the workshop scratching my head!
I will try and scale the body and then alter it to accommodate the Honda engine and driver etc. I think if I try a more free style approach it will end up looking a bit silly! It sounds like people alter the length of the bonnet and rear tub to make things fit.
Post by: ChrisS on 02 Nov 20, 07:59 am
Post by: StefanN on 02 Nov 20, 08:29 am
Pitbike wheel with 3.25 tyre. Diameter 600mm
Pitbike wheel with 2.50 tyre. Diameter 570mm
Post by: Marek.Z.N on 02 Nov 20, 09:08 am
Post by: Marek.Z.N on 02 Nov 20, 09:10 am
Post by: Marek.Z.N on 02 Nov 20, 10:24 am
Post by: TheGiantTribble on 02 Nov 20, 05:29 pm
A couple of comments/suggestions re scaling.
Your height, width, and length can all be scaled, but remember they doesn't have to be to the same scale as each other. A bit like models trains bod is to one scale but the tracks can be to something else.
I found the scuttle, or rather leaving it off all together can make a big difference to the fitting the human in problem.
Probably the most important measurement is the height of the waist bulkhead/instrument panel because of entrance and exit, my first go at a CK involved being able to get in but not out!
Good luck and go for it.
Post by: Mark Underdown on 02 Nov 20, 09:52 pm
I will push on with some drawings and see how it ends up!
Thanks
Mark
Post by: Mark Underdown on 08 Nov 20, 07:11 pm
Following a visit to see Stefan’s very nice Bugatti and several attempts at scaling the chassis for my build I took the plunge and welded a chassis up.
I figure if it’s wrong I can soon cut and shut it etc!
Front axle next,
Post by: Marek.Z.N on 08 Nov 20, 09:01 pm
Post by: jim on 09 Nov 20, 06:20 am
Post by: Mark Underdown on 09 Nov 20, 06:11 pm
I think to try and weld 1.6mm ERW box I would of had to buy 0.8 mig wire, tips etc.
Welding 2mm steel with 1mm wire was not the easiest!
Post by: RhysN on 09 Nov 20, 06:50 pm
Post by: Mark Underdown on 09 Nov 20, 10:24 pm
Thanks Mark
Post by: RhysN on 10 Nov 20, 08:04 am
Post by: Mark Underdown on 10 Nov 20, 08:33 pm
can anyone advise what size springs work well on the front, width, thickness length would be handy.
I was contemplating having a go at making some springs myself, this might prove tricky though.
Post by: StefanN on 11 Nov 20, 12:23 am
http://www.cyclekartsgb.com/where-to-get-stuff/leaf-springs-eternal/
Post by: RhysN on 11 Nov 20, 12:17 pm
Post by: Mark Underdown on 11 Nov 20, 09:01 pm
I am investigating making some as it is going to get expensive to buy 4 springs.
Post by: Mark Underdown on 25 Nov 20, 07:15 pm
The springs are quarter elliptic on the Fraser Nash.
After quite a few failed attempts with some old mild steel flat bar I managed to get a very poorly made jig to bend the eyes with a degree of repeatability.
I then managed to roll 4 springs, 2 fronts and two backs to the same shape using the correct steel.
I think I will make some standard leaf springs with eyes at both ends and some helper leaves to help carry my weight after Xmas!
It was a bit more difficult than I anticipated but I got there in the end. I am not going to heat treat them until I have them fitted to the chassis as I can still change the radius at the moment.
Post by: synthpunk on 25 Nov 20, 09:58 pm
Post by: Applejack on 26 Nov 20, 08:56 am
Post by: Mark Underdown on 26 Nov 20, 09:04 pm
Post by: Mark Underdown on 12 Dec 20, 10:47 pm
Post by: jim on 13 Dec 20, 07:44 am
Post by: RhysN on 13 Dec 20, 10:48 am
Post by: Mark Underdown on 13 Dec 20, 05:48 pm
I will get it welded up this week.
Post by: Marek.Z.N on 14 Dec 20, 04:29 pm
Post by: Mark Underdown on 11 Jul 21, 07:18 pm
Hopefully I will be able to get some more workshop time soon.
Post by: RhysN on 11 Jul 21, 08:41 pm
Post by: Marek.Z.N on 12 Jul 21, 07:55 am
Post by: StefanN on 13 Jul 21, 10:11 am
Post by: Mark Underdown on 13 Jul 21, 11:06 pm
Hoping to get it running by the end of August, seems to take awhile though. The diff turned out to be a pain as the shafts are 1 inch and everything else is 25mm so all the hubs etc needed reaming in the lathe to fit.
I need to finish the front axle next!
Post by: jim on 14 Jul 21, 06:23 am
Is the lay shaft there so you can get the drive ratios you want without having big sprockets and allowing the seat back to be closer to the rear axle?
The diff should give you very nice handling in tight corners. I'm glad I fitted one to my kart.
Post by: Mark Underdown on 14 Jul 21, 07:15 am
Yes I put a lay shaft in to help keep the sprocket small but mainly so it’s very easy to achieve a much greater range of gear ratios.
With the sprockets I have it is currently set to 7.5-1 not including the Torque converter but by changing one small sprocket I can get anything from 6-1 up to 10-1
Obviously not having finished the kart I have no idea what the best gear ratio is but I know from using Honda engines at work they like to run at the top end.
Post by: Mark Underdown on 21 Nov 21, 07:51 pm
Hoping to get this running by Christmas so I can get on with the body.
Using the pearless diff has proved to be a bit of a pain, all the hubs etc are standard 25mm where the diff is 1inch so I have had to bore everything out to fit.
Having done that I have machined the slots in the axle and lay shafts for the key ways today.
Small jobs but I think I can now assemble the backend now and not take it to bits again until it needs painting.
Post by: Mark Underdown on 24 Dec 21, 02:13 pm
A few smaller jobs to do but finally finished machining and welding and can start the bodywork!
Post by: Marek.Z.N on 26 Dec 21, 04:40 pm
Post by: Mark Underdown on 27 Dec 21, 04:14 pm
I was going to make a grp body but I really want to get this finished now ready for 2022, so I have opted for aluminium panels which I think will be a faster approach.
The front nose cone and engine cover may still end up being grp, I’m not good enough at panel beating to make these from aluminium.
I made the first two panels up today.
Post by: Marek.Z.N on 27 Dec 21, 04:33 pm
aslo... GRP? is that a different name fore fibreglass or is that a different material. not heard of it before.
Post by: Mark Underdown on 27 Dec 21, 06:03 pm
The other folds where done using a lump of 40mm square steel as a dolly and a hammer.
I will take some pics when I make the next two panels.
Trying to keep it as close to the original as possible within reason.
The Louvers are going to be a problem to form and unfortunately the original has an awful lot of them!
I think GRP is fibreglass to anyone without any knowledge of the subject. There probably is a difference?
Post by: Marek.Z.N on 27 Dec 21, 06:20 pm
Post by: RhysN on 28 Dec 21, 06:53 am
Post by: Mark Underdown on 28 Dec 21, 10:43 pm
Bent on the bench as before, a sheet metal folder would definitely help with this job!
I think I may have to find a Louvre tool, my tig welding isn’t up to welding in pre formed panels, I suspect the distortion would be a nightmare.
Post by: jim on 29 Dec 21, 06:52 am
Post by: StefanN on 29 Dec 21, 08:57 am
I’ve used pre-made air vent louvres and also have made them with a simple die. Not much to choose between them. With a die you get to choose the shape, length and spacing. Pre-made are pretty cheap and low risk
The simple die I copied from someone in the US:
http://www.cyclekartsgb.com/build-journals/bugatti-type-37-build/msg811/#msg811
Post by: RhysN on 29 Dec 21, 09:50 am
Post by: Mark Underdown on 30 Dec 21, 04:40 pm
I don’t think I will be able to bend the bonnet very easily so I am going to make a plywood former up to bend it around which will slow things up a bit.
I am not going to worry about any details like louvres until it is up and running, really keen just to get it to the stage it can be used and refine it after that otherwise there is a very real danger this could run into 2023!
We use Tiger seal at work a fair bit and it is amazing stuff, the only downside is once it’s used you can’t take things to bits again. We also use Sikaflex which comes in various grades and is probably stronger than Tigerseal for some applications. I might use some Tigerseal on the body rather than having too many rivets showing.
Post by: Mark Underdown on 29 Jan 22, 10:41 pm
Does anyone know off a good source of leather bonnet Fastners that doesn’t involve me learning to be a tanner and leather worker. Looking for more of an Amazon Prime solution!
Post by: Seven racer on 29 Jan 22, 10:58 pm
The buckle and fittings are already done for you, you just might need to fabricate ally plates where the ends attach to the body.
Peter
Post by: Mark Underdown on 30 Jan 22, 09:25 am
Thanks Mark
Post by: RhysN on 30 Jan 22, 01:27 pm
Post by: Mark Underdown on 26 Feb 22, 06:45 pm
It’s nice to be bolting items to it that hopefully wont have to be removed again, I have lost count of the number of times the back axle has been put on and taken off again!
Post by: RhysN on 26 Feb 22, 08:47 pm
Post by: Mark Underdown on 26 Feb 22, 09:02 pm
I’m not sure what gear ratio other people are running?
Post by: RhysN on 26 Feb 22, 09:08 pm
Post by: RhysN on 26 Feb 22, 09:11 pm
Post by: Mark Underdown on 26 Feb 22, 09:23 pm
I have a 10 tooth sprocket on the tav driving a 40 tooth,
This then drives a 13 tooth to a 30 tooth on the diff. Giving 1 to 9.23
If I change the 13 tooth to 16 it should bring it to 1 to 7.5
I put the idler so I could achieve different gear ratios easily.
I guess the question is how hard is everyone revving the engines at the moment?
(I really hope my maths is correct now) :)
Post by: Mark Underdown on 13 Mar 22, 05:51 pm
I spent an afternoon welding the chassis up because most of it was tack welded up to this point.
At long last I am bolting things in place for the final time, so hopefully within a week or two it will be running and driving.
Weighed it today as well and all up it is 103kg which is probably heavy but less than I thought it would be.
Biggest worry now is how the steering will behave.
Post by: jim on 13 Mar 22, 06:31 pm
I am looking forward to seeing it at a meeting soon.
Post by: Mark Underdown on 13 Mar 22, 06:53 pm
As a man who needs a deadline to finish any project when is the first meeting likely to be where we can drive these cars.
Post by: StefanN on 13 Mar 22, 09:37 pm
Post by: Mark Underdown on 13 Mar 22, 10:20 pm
The steering box is from some kind of industrial food processor, it has a 2:1 ratio, I don't think a 1:1 ratio would work very well the steering would be very heavy. I'm trying to find a 1:3 ratio to make it a bit lighter.
Also being a T drive angle gearbox it can be flipped over to get the direction of rotation correct, saves a lot of head scratching!
I got lucky and found it on Ebay for £14.00 including postage, I have tracked down a company that sell them new from the markings on the case which I can forward to you when I find the email.
Post by: Tinworm on 13 Mar 22, 10:35 pm
Like this (just quickly cut it onthat is a good idea, Marek!
Post by: David F-R on 14 Mar 22, 08:34 am
Stefan
The steering box is from some kind of industrial food processor, it has a 2:1 ratio,
Please do tell us more.
Post by: Mark Underdown on 14 Mar 22, 09:46 pm
http://www.davall.co.uk/media/59919/2000_series_2___3_shaft.pdf
Unfortunately they are expensive at over £220 plus vat and delivery which is why i went the ebay route for a used one.
The part number for the one I was discussing is: 182011131 this one has a 1:3 ratio instead of a 1:2 ratio which I found used.
If looking on Ebay searching Poggi Gearbox or Bonfiglioli bevel gearbox might help, be warned some have very small shafts 5-6mm which I dont think would be strong enough, they share castings so look pretty similar. Mine has a 15mm diameter shafts which I think is about right for strength and weight.
I don't think the steering would work with a 1:1 ratio very well.
Post by: Tinworm on 14 Mar 22, 11:11 pm
Post by: David F-R on 15 Mar 22, 10:09 am
https://www.ebay.co.uk/itm/284679275374?hash=item424835036e:g:k88AAOSw90piIJ9Z
spec. at https://www.dztrasmissioni.it/en/products/gear-drives/inox-dz-series/size-2-flanges-3-inox/
£100 new on ebay.
Post by: Mark Underdown on 15 Mar 22, 11:12 am
They do come up mine was £14 on eBay new old stock.
Post by: Mark Underdown on 26 Mar 22, 09:18 pm
I went into the workshop at 7am determined to only come out when I could drive out in the Kart.
There seemed to be a huge list of small jobs, welding the exhaust up, quick release steering wheel, fixing the steering UJs, bleeding brakes, putting a floor and seat in, building an accelerator pedal assembly, tensioning chains etc etc.
By 4pm I had it pretty much buttoned up and flying round our gravel yard. The accelerator turned into a bodge that needs reworking when I get the cable clamps but it worked well enough for a test drive.
The steering worked much better than I expected and was much lighter once I pumped the tyres up!
Looking forward to moving on with the body work now, I have started making a plaster buck for the front end.
Post by: Chris L on 26 Mar 22, 09:51 pm
Chris L
Post by: synthpunk on 26 Mar 22, 10:23 pm
Post by: Jimr1999 on 27 Mar 22, 06:11 am
Post by: Tinworm on 27 Mar 22, 12:03 pm
Happy day today, I got to drive my cycle kart for the first time.
That must be an epic feeling! Congratulations, Mark!
Post by: Mark Underdown on 27 Mar 22, 03:20 pm
Post by: David F-R on 27 Mar 22, 07:37 pm
Post by: Mark Underdown on 22 May 22, 03:21 pm
helper springs added at the front the single leaf seemed quite soft on its own.
The exhaust I purchased was ridiculously loud so I spent a bit of time altering it adding internal drilled tubes and baffles and it seems to have worked.
It’s amazing how much time all the small jobs have taken to get it up and running, hopefully now I can get on with some more cosmetic jobs.
The front nose cone is Kubota grey because I was painting some parts at work that colour the other day and it got in the way. Just looked better for now than bare fibreglass.
Hopefully it will be out on Tuesday.
Post by: Jimr1999 on 22 May 22, 03:37 pm
Post by: Mark Underdown on 22 May 22, 03:45 pm
That is looking really sorted on the front end now Mark. I bet you are itching to get it around a track. :)
Very keen! although a little worried what will fall off first. :)
Post by: Mark Underdown on 01 Apr 23, 08:53 pm
I have made the body of the kart 50mm narrower overall to try and make it look a little better, this meant cutting the bonnet in half and making a new nose cone.
While I was at it I have dropped the seat 70mm with an aluminium tray to get the centre of gravity down a bit.
There wasn’t much time to worry about cosmetics last year, so louvres have been added that will hopefully will make it look a little better.
A new rear end was todays grp project, last years bent piece of aluminium fell foul of the endurance race where it fell into one of the rear wheels!
Hopefully next weekend will see some paint applied to the body, ready for the next event!
Post by: Moogie38 (Noel) on 01 Apr 23, 10:04 pm
Post by: jim on 02 Apr 23, 05:21 am