CAV WEB Site Updated w/Mono
- Thread starter JayT
- Start date
Hi Jay
Well I for one expected the new monocoque to follow the lines of the original GT40 in
the same way as the ERA. It looks to me like a compromise so that the old GTD front
suspension arms will still fit. It also looks therefor that the footwell space will still be
very small unlike some of its competitors.
I do not think that this is a true monocoque either as I can still see tubing forming the
rear bulkhead. It looks as though the steering rack is now in the right place, so bump
steer should be eliminated.
They have kept the images very small are they trying to hide the detail?
What a missed opportunity to make an authentic looking monocoque, ERA are still
streets ahead of the field in my opinion.
Chris Melia
[ March 23, 2002: Message edited by: Chris Melia ]
Well I for one expected the new monocoque to follow the lines of the original GT40 in
the same way as the ERA. It looks to me like a compromise so that the old GTD front
suspension arms will still fit. It also looks therefor that the footwell space will still be
very small unlike some of its competitors.
I do not think that this is a true monocoque either as I can still see tubing forming the
rear bulkhead. It looks as though the steering rack is now in the right place, so bump
steer should be eliminated.
They have kept the images very small are they trying to hide the detail?
What a missed opportunity to make an authentic looking monocoque, ERA are still
streets ahead of the field in my opinion.
Chris Melia
[ March 23, 2002: Message edited by: Chris Melia ]
G
Guest
Guest
Chris
You may be right, but one thing is for sure,
$ 63k for a fully assembled and painted
monocoque is a good value. An ERA KIT
will set you back $ 55k and that doesn't include the trans, exhaust, etc.
FYI it appears that like ERA, CAV uses a seperate, fibreglass roof. I believe
John Hester's monocoque will not only be
closer to the original GT40 form, but also
have a steel roof.
MikeD
You may be right, but one thing is for sure,
$ 63k for a fully assembled and painted
monocoque is a good value. An ERA KIT
will set you back $ 55k and that doesn't include the trans, exhaust, etc.
FYI it appears that like ERA, CAV uses a seperate, fibreglass roof. I believe
John Hester's monocoque will not only be
closer to the original GT40 form, but also
have a steel roof.
MikeD
I remain amazed that a modern "monocoque" does not have the roof and windscreen pillars as coherent structural parts of the chassis.
The strength and safety issues are obvious..
What was ok 30 years ago may not be now..especially if modern racing tyres are being used!
To have a mono that finishes at hip height may be closer to the original design, but why ignore all those decades of learning and thinking?
The strength and safety issues are obvious..
What was ok 30 years ago may not be now..especially if modern racing tyres are being used!
To have a mono that finishes at hip height may be closer to the original design, but why ignore all those decades of learning and thinking?
Ron Earp
Admin
Chris,
I took at look at the photos as well and it appears to be a carefully sheeted space frame. Not all of it mind you, but certainly in the firewall area and some of the scuttle frame around the dash. The photos are too small to really tell, but it looks like a modified space frame chassis. Hard to tell, I hope to visit those folks next time I'm in CA so I can see what they really look like.
Ron
I took at look at the photos as well and it appears to be a carefully sheeted space frame. Not all of it mind you, but certainly in the firewall area and some of the scuttle frame around the dash. The photos are too small to really tell, but it looks like a modified space frame chassis. Hard to tell, I hope to visit those folks next time I'm in CA so I can see what they really look like.
Ron
As I am near the point of purchase I have studied the pictures closely. I agree with the comments that it appears to be a sort of hybrid. The boxed sections in the dash area, cabin hoop, and rear suspension/endinge support. One thing I noticed that is of particular concern is that the coolant pipe (on the left front) is unprotected and runs just along the front wheel. The chance of damage is high.
G
Guest
Guest
Robert,
""I remain amazed that a modern "monocoque" does not have the roof and windscreen pillars as coherent structural parts of the chassis.""
actually the original design does incorporate the A pillars and roof into the monocoque, but it does not get much rigidity from them due to the cut of the doors into the roof.
I think the reason that the kits don't use steel A pillars and roof is that constructing them is very labor intensive and difficult due to the compound curves. This is the only place the original chassis coincides with the outer body so the compound curves are necessary. And the fact that it doesn't give much to the rigidity anyway so isn't worth the extra effort, hence the easier material, fiberglass.
the roof is one of the weak points of the original chassis design although it is very adequately compensated by the side (rocker) torsion boxes. Even with a full steel A pillar/roof you don't get much roll protection. This may be why they added roll bars to some racing GT40's.
to illustrate the door problem with the GT40 here's a pic of a saleen race car (thanks Chris Melia) that has a similar door and what they did to compensate(not pratical for the road) Note the tubing from the top of A-pillar too top of B-pillar
and to illustrate my point of previous discussions about tube frames and triangulation (once again thanks to Chris).
This T70(copy?) chassis is what's known as "fully" triangulated http://www.gt40s.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=000256&p=2
another little note about the original chassis. The original windshields were triple laminate (as opposed to the common double). Made by a company called Triplex(?). They built(build?) windscreens for boeing. I believe the triple laminate windshield was incorporated as part of the chassis structure to increase rigidity.
as I was typing this reply my flywheel/clutch/starter arrived from KEP, yeee haaa! 600 ft/lb torque custom aluminum pressure plate. 1/2 the weight of a stock porsche unit. SWEET. KACHUNK, uh oh, large piece of wallet is now missing.
[ March 26, 2002: Message edited by: Kalun D ]
""I remain amazed that a modern "monocoque" does not have the roof and windscreen pillars as coherent structural parts of the chassis.""
actually the original design does incorporate the A pillars and roof into the monocoque, but it does not get much rigidity from them due to the cut of the doors into the roof.
I think the reason that the kits don't use steel A pillars and roof is that constructing them is very labor intensive and difficult due to the compound curves. This is the only place the original chassis coincides with the outer body so the compound curves are necessary. And the fact that it doesn't give much to the rigidity anyway so isn't worth the extra effort, hence the easier material, fiberglass.
the roof is one of the weak points of the original chassis design although it is very adequately compensated by the side (rocker) torsion boxes. Even with a full steel A pillar/roof you don't get much roll protection. This may be why they added roll bars to some racing GT40's.
to illustrate the door problem with the GT40 here's a pic of a saleen race car (thanks Chris Melia) that has a similar door and what they did to compensate(not pratical for the road) Note the tubing from the top of A-pillar too top of B-pillar
and to illustrate my point of previous discussions about tube frames and triangulation (once again thanks to Chris).
This T70(copy?) chassis is what's known as "fully" triangulated http://www.gt40s.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=000256&p=2
another little note about the original chassis. The original windshields were triple laminate (as opposed to the common double). Made by a company called Triplex(?). They built(build?) windscreens for boeing. I believe the triple laminate windshield was incorporated as part of the chassis structure to increase rigidity.
as I was typing this reply my flywheel/clutch/starter arrived from KEP, yeee haaa! 600 ft/lb torque custom aluminum pressure plate. 1/2 the weight of a stock porsche unit. SWEET. KACHUNK, uh oh, large piece of wallet is now missing.
[ March 26, 2002: Message edited by: Kalun D ]
I think you might be referring to the Triplex "ten twenty" glass laminate?
It was revolutionary at the time, although the details are lost in my grey matter.
Further to triangulation for strength, take a look at the latest Subaru World rally Car www.src.com
Rob
It was revolutionary at the time, although the details are lost in my grey matter.
Further to triangulation for strength, take a look at the latest Subaru World rally Car www.src.com
Rob
G
Guest
Guest
Chris, I'm going to have to side with Bob Lacey on this one. Added tubing doesn't necessarily mean it's not a monocoque. The originals and the ERA have tubing in numerous places.
Looking at Dave Warren's ERA pics I see tubing in the front and rear bulkheads and inside the rocker torsion boxes.
The rocker torsion boxes (a critical piece) on the GTD look even more substantial than the ERA. And I've always liked the look of the GTD uprights.
I think this is good competition for ERA, and that always leads to better more affordable products for the consumer.
ERA may be the industry leader, they do have a considerable head start. But now they won't be able to rest on their laurels.
[ March 26, 2002: Message edited by: Kalun D ]
Looking at Dave Warren's ERA pics I see tubing in the front and rear bulkheads and inside the rocker torsion boxes.
The rocker torsion boxes (a critical piece) on the GTD look even more substantial than the ERA. And I've always liked the look of the GTD uprights.
I think this is good competition for ERA, and that always leads to better more affordable products for the consumer.
ERA may be the industry leader, they do have a considerable head start. But now they won't be able to rest on their laurels.
[ March 26, 2002: Message edited by: Kalun D ]
Hi kalun
I would have preferred to have the cooling tubes running through the central tunnel
instead of under the wheel arches. It sounds as though the old GTD foot well may
have been increased in dimension, but I still think that it still will not match its
competitors.
Yes some strengthening tubes are necessary when manufacturing a GT40 monocoque
but if too many are employed then you might as well stick with a space frame.
I do not see a problem with a carbon fiber roof section to help with rigidity.
I just wish that it would have followed the style and arrangement of the original tub
especially at the front with larger foot wells and floor mounted pedals and anti-dive
suspension layout.
The arrangement for the rear roll bar on the ERA I think is ideal and looks very authentic
so why not employ this type of design.
I do not condemn the new CAV semi monocoque but feel that it could have followed
the original layout, instead of being limited to the constraints force on the new design by the use of components from the old space frame .
I would like to see some better photographs.
Chris
Does CAV = GTD? do they still work together?
I would have preferred to have the cooling tubes running through the central tunnel
instead of under the wheel arches. It sounds as though the old GTD foot well may
have been increased in dimension, but I still think that it still will not match its
competitors.
Yes some strengthening tubes are necessary when manufacturing a GT40 monocoque
but if too many are employed then you might as well stick with a space frame.
I do not see a problem with a carbon fiber roof section to help with rigidity.
I just wish that it would have followed the style and arrangement of the original tub
especially at the front with larger foot wells and floor mounted pedals and anti-dive
suspension layout.
The arrangement for the rear roll bar on the ERA I think is ideal and looks very authentic
so why not employ this type of design.
I do not condemn the new CAV semi monocoque but feel that it could have followed
the original layout, instead of being limited to the constraints force on the new design by the use of components from the old space frame .
I would like to see some better photographs.
Chris
Does CAV = GTD? do they still work together?
G
Guest
Guest
Robert,
yes my knowledge of the triplex is incomplete also. What I do know is that it's 3 layers of glass and 2 layers of plastic, it does add to torisional rigidity and that nowadays it will set you back $1800.00.
Chris, agree on most of your points.
During my design phase I never considered putting the coolant pipes outboard although it's crowded were they come into the bottom/center of the engine compartment. I did compromise by locating the shifter on the left outboard side (LH drive) as this considerably symplified the shifter mechanism and relieved crowding/complexity in the center tunnel area. Maybe a consideration in the GTD design. I do think that something that appears to be a disadvangtage may have an advantage in other areas.
I also favor the angled chassis were the front arms mount although you can achieve anti-dive without it.
I definitely would like more/better pics from all the manufactures (although that has improved). Being sort of isolated in the pacific NW I don't get a chance to look at a lot of different makes in person. Dave's ERA pics are the first I've seen of an ERA bare tub.
I do have to admit a bias I usually root for the underdog.
yes my knowledge of the triplex is incomplete also. What I do know is that it's 3 layers of glass and 2 layers of plastic, it does add to torisional rigidity and that nowadays it will set you back $1800.00.
Chris, agree on most of your points.
During my design phase I never considered putting the coolant pipes outboard although it's crowded were they come into the bottom/center of the engine compartment. I did compromise by locating the shifter on the left outboard side (LH drive) as this considerably symplified the shifter mechanism and relieved crowding/complexity in the center tunnel area. Maybe a consideration in the GTD design. I do think that something that appears to be a disadvangtage may have an advantage in other areas.
I also favor the angled chassis were the front arms mount although you can achieve anti-dive without it.
I definitely would like more/better pics from all the manufactures (although that has improved). Being sort of isolated in the pacific NW I don't get a chance to look at a lot of different makes in person. Dave's ERA pics are the first I've seen of an ERA bare tub.
I do have to admit a bias I usually root for the underdog.
Kalun, I too am constructing a left hand drive,left hand shift replica. At this point I have not designed/installed my shift mechanism. I have not identified a domestic shifter that I can modify to suit the requirements. Would you care to share some thoughts on your approach? Thanks, Brian
Kalun D,
The pics I posted of my ERA chassis have no tubing on them...yet. The pieces you think are tubing are fabricated out of sheet stainless. Correct me if I'm wrong Bob P., but the only tubing on a completed chassis are the pieces added that stick out in front of the front bulkhead to support the radiator and front body bodywork, and like pieces that extend beyond the rear suspension hoop that support the rear bodywork. Here'a picture of an ERA car taken 2 years ago that shows the front support tubing.
and another of 2 bare chassis laying one on top of the other, also taken 2 years ago
The stiffner pieces you see in the rocker panels are not tubing.
You may be able to get a little better look if you go to the "album" where I have the pictures. I beleive you can view them full screen from there.
]http://www.clubphoto.com/reward.php?id=694033&mid=members7_dave539245&pwd=]
Dave
[ March 26, 2002: Message edited by: DaveWharran ]
The pics I posted of my ERA chassis have no tubing on them...yet. The pieces you think are tubing are fabricated out of sheet stainless. Correct me if I'm wrong Bob P., but the only tubing on a completed chassis are the pieces added that stick out in front of the front bulkhead to support the radiator and front body bodywork, and like pieces that extend beyond the rear suspension hoop that support the rear bodywork. Here'a picture of an ERA car taken 2 years ago that shows the front support tubing.
and another of 2 bare chassis laying one on top of the other, also taken 2 years ago
The stiffner pieces you see in the rocker panels are not tubing.
You may be able to get a little better look if you go to the "album" where I have the pictures. I beleive you can view them full screen from there.
]http://www.clubphoto.com/reward.php?id=694033&mid=members7_dave539245&pwd=]
Dave
[ March 26, 2002: Message edited by: DaveWharran ]
A possible shifter to use is a 911 or 914 as short shift kits are available and they already have the correct throw for a porsche transaxle
Jim Rosenthal
Supporter
If you look at the chassis from the Safir Mk5 cars, I think you will see that similar adaptations were made to suit the changes in construction- essentially the difference between a chassis made completely of welded-up stampings, and one simplified so that many of the sections could be fabricated on a brake and then welded together. (if my terminology is wrong, I apologize, I am no metalworker). The sponsons, or whatever they are called, on a Safir chassis look similar to what I see on the ERA monocoque, and I think they are made of metal sheet sections folded and welded into place.
Didn't all the GT40s have some areas in the monocoque which have tubing sections welded in, or am I mistaken?
Didn't all the GT40s have some areas in the monocoque which have tubing sections welded in, or am I mistaken?
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