M20 Dreaming

[Leon]

Hi Jack, 13.75" at the pedal face and 15.75"at the hip position in the seat area and the same on the passenger side. I'm 5' 8" and pretty solid Build and there won't be a lot of padding on the sides of the seat and you don't drive this in work boots if you get my drift. The other thing is there is only 10" height in the foot well, with my race shoes (size 9) I can operate the pedals but there is not a lot of spare room above my toes, also the steering rack goes through the same space about 6" back from the pedals (just above your ankel) so sliding in and out is an art.

Hi Russ, you could be right?? I sort of copied the Tilton pedals so time will tell, as you may notice the brake pedal has not been painted as I still have to weld the balance bar in so I may take your advice and box the the front. thanks for the positive coments. I'm pretty happy with how its coming together so far and once the dash is done and the steering rack and suspension it should look pretty close to the original.

Cheers Leon

 

[Jack Dunn]

Thanks for the dimensions Leon: I've been in a lot of sports racers and I'm interested in the room the designers allow for the driver

Jack

 

[Mick Ridley]

Hi Leon.


your car is looking great....

have you seen these rivets... They are very strong, and their blind side looks good.You wont need to use washers, on the blind side. They are used and recomended by Kit plane manufactures. They cost about £30 per thousand

Avdel Global :: Avex®

Aircraft Construction, Riveted Joints

mick

 

[Terry Oxandale]

Hi Jack, 13.75" at the pedal face and 15.75"at the hip position in the seat area and the same on the passenger side. Cheers Leon

Now I don't feel so bad. I've the exact same dimensions in the tub, and with the seat inserted, it will be about a quarter inch less at the hip. So I've got to watch any weight gain, if nothing else then to be able to easily fit in the seat.

Ox

 

[David Sturch]

Terry & Leon,

I was thinking of making up a couple of large shoe horns. Or a little Mazola to help the slide in.
Dave

 

[Terry Oxandale]

Haven't seen much on the Chevron lately...any progress pics?

 

[kiwi ka]

Leon
Did i read further back that you were thinking of using fibre glass for your tank lining, that is pretty common in marine situations so for better info try HIGH MODULAS SYSTEMS OR EPIGLASS and they have specialist info that makes the task easy.
I have used resin for both marine exhausts and tanks before so its really easy to make custom shapes.
Love the work done so far and will get to see it one of these days.
Russell

 

[Leon]

HI , Had a break from the alloy fabrication and made the engine tripods. These are the tube frame's that extend from the rear bulkhead back to the bellhousing. they are mounted in the same box section as the rear trailing arms and from the outside pod and with the front engine plate and the rear stays for the roll bar mount the whole rear section of the car. I used 1'' tube and 3mm plate for the attach point on the bellhousing, the rodends give fine adjustment for alignment of the engine/trans to the tub. Will continue on with the front suspension and dash this week. Cheers Leon

 

[Leon]

Hi Guys, Just had 5 months at home waiting for a new posting so got a bit done on the car, the front suspension and the dash top are nearly complete and have been playing around with shocks, the big thing I progressed with was making the die for the rear wheels. Again the use of custom wood is the main building product and what I have done is cut out rings of 25mm customwood and glued them together, once set I then put them in the Lathe and turned them down to the correct shape, leaving enough meat to allow for the alloy srinkage. At this point I have made it in 3 parts, the outer shell, the centre and the iner shell. I will then talk to the Casters and see if they can cast the wheel in 1 peice the other option is to cast the centre and iner as 1 and then the outer can be either bolted or welded later. the rear wheel is 19" wide and the centre and iner are the same for the front so I only have to make a smaller outer for the front which is 11" wide. I do have some photos but I don't have access to them as I'm at work now untill 22nd March. Will post some pics of the finished items when I'm Home. Cheers Leon.

 

[Terry Oxandale]

Looking forward to seeing more progress!

 

[Leon]

Back to working on the car, This time I have worked on the wheel mould, the front suspension and dash. The wheel mould is starting to look good now and I only need to finish a bit of machining on the centre and then get some paint on it and assemble it up and get it to the Foundry and see if they can cast it in one piece. The dash is just more sheet fab work, I have made the mock up from cardboard then used the patterns to make the alloy panels. I will complete the top in one piece and then fit the steering rack before nailing the dash down for good as there isn't a lot of room to work in under the dash. The front suspension is taking a bit of working out as it is the one part of the car I don't have a lot of photos of, so I'm pretty much going on some very basic info and my own ideas. Here are some pics so you can see where i'm heading. The pics of the front suspension are set at 4" ride height with 23" tyres. Cheers Leon. And I did some work on the mould for the bellhousing, just need to do a bit of finish sanding and painting.

 

[Howard Jones]

One sugestion kindly made. You picture of the front suspenssion shows the forward lower A-arm mount in in single shear. This suspension pickup point is under pretty heavy loading, especially under breaking. I thing if you did something like you did on the top in double shear it would be stronger and better.

Your project is really cool, The M20 is my favorite of all the Canam cars. Really nice work, keep it up.

 

[Terry Oxandale]

Somewhat related, what angle will you end up with relative to the horizontal on the shock/spring assembly?

 

[Andrew Robertson]

Back to working on the car, This time I have worked on the wheel mould, the front suspension and dash. The front suspension is taking a bit of working out as it is the one part of the car I don't have a lot of photos of, so I'm pretty much going on some very basic info and my own ideas. Here are some pics so you can see where i'm heading. The pics of the front suspension are set at 4" ride height with 23" tyres.

Hi Leon, awesome progress - those wheels are going to be wicked.

On your front end - I offer a couple of thoughts: the expedient approach of using the same axis to mount top inner link and top of shock creates a reducing rate suspension, where spring rate steadily reduces under bump - the opposite of what is required, and as has been pointed out I think the inclination is a bit severe too. I think you need to mount the top of the shock higher and outboard of the inner top link mount (at a super-wild-arsed guess I'd say 2 inches higher and 2 inches outboard). Someone here will no doubt have the science and the photos to help you get it spot on.

Keep it up.

Cheers, Andrew

 

[Terry Oxandale]

All of these latest posts sort of blend together in my mind. With the apparent angle (the photograph may be distorting the angle though) of the assembly, the first thing I wondered was how much this lower angle increases the shear loading on the single shear point (queried earlier).

 

[Leon]

Hi guys, I appreciate your in put so will answer the Questions by Name.
Andrew, I hear what you are saying re the suspension geometry but I'm trying to replicate the M20 and all the photos I have of the McLarens from the M6a to the M8F Have the top link and shock on the same mounting bolt. The reading I have done says the M20 suspenion was a carry over from the M8F, same uprights, arms, links and shocks the only difference being the discarding of the steel bulkhead in the front of the tub and using steel brackets mounted to the alloy tub insteed.

Howard/Terry, The shock position was still under review when I took the photo and I have since repositioned the bottom eye below the arm as it is in the M8F, this gives me an angle 50deg to the Horizontal. As for the single shear, I have been debating this with myself and after more study of the M8F photosand a drawing of the M20 will change this and put a alloy box section through the bottom which will make them double shear. I was just being lazy as it also meens I have to lenghten the push rods on the pedalbox as the master cylinders have to move forward and mount on the box section as well. There is a pic of the shock position below, Cheers Leon

 

[Terry Oxandale]

I felt so uncomfortable saying anything because I so highly respect what you've done and are doing.

It has been so highly emphasized by experienced designers (away from this forum) about the impacts of low angle on the joints as well as reducing-rate issues, I just had to ask. My upper attachment point (granted, my interpretation of the McLaren is going to be a LOT looser than yours will be) is within 3mm of the bodywork just so I could get what I consider a fair angle (60º from the horizontal). I think a lot of my concern was more from photographic distortion in your images than from actual angles though.

 

[Leon]

Hey Terry, Feel free to coment mate, Thats what this forum is for and we all learn from each other. It has made me re think the front end and the result will will be a better finish and more authentic. Cheers Leon

 

[Mesa]

I'm with you Terry - Personally it's kind of hard for me to comment when Leon's build is way out of my league. I do enjoy seeing what he is doing and how it gets done, very educational. I tune in to this thread whenever something is posted, like he said we all learn form each other ... and class is in session here (and in your thread) for me.

 

[Leon]

Last post for a while as I'm back to work tomorrow. I have been working on the front suspension and dash, I haven't done the double shear on the bottom link yet But have spent time on getting the angle on the shock to 55deg. I moved the top mount out 1" and the bottom mount back in and lower in the "A"arm. I also fitted the foot vent, The dash is almost done, Will mount the steering rack next time home and do the other side and that will be the front almost complete. Well thats it, here's some photos
Cheers Leon.