540HP NA 7L V12 3 seater
Discussion
LaurasOtherHalf said:
What do you expect the handling of the car to be like with the two outboard engines? Obviously you'll be achieving a very central CoG from front to rear but the weight will be quite uniquely spread across the chassis from side to side, do you anticipate any issues with roll centres?
Scary at first! There are so many suspension parameters which will require adjustment to give a stable and benign driving experience, I think that is one of the most challenging aspects of the project, given I don't have a calibrated butt. The engine masses each side are equal distance from the COM of the vehicle, so using the parallel axis theorem (thanks for getting me to dust off my old textbooks!) they have the same mass moment of inertia as an engine twice the size at the same distance. I hope the picture below helps, since the radius from the center of mass is the same for both engine types the equation shows that 2 engines of mass m equals one engine of 2m at the same radius - i.e. 2(mr^2)= 2mr^2 - in the horizontal plane (Yaw).
Yazza54 said:
Roll centres are a function of suspension geometry and ride height not where the weight is placed.
agreed, and the center of mass distance to the roll axis gives the roll moment that the vehicle is subjected to in cornering. I need to examine if the center of mass of 2 equal engines symetrically either side of the centerplane is the same as having one big lump in the middle - have not looked at the S70/2 com to roll centre as I have no data. However I think LaurasOtherHalf is right in that the lateral roll inertia of the 2 engines in the vertical plane might be greater than a centralised lump. So the twin engine layout may be slightly more resistant to roll if its lateral inertia is higher.... It will be not be that different from an F1 carrying a couple of passengers, interesting to see if they reduce the roll response - time to ask Flemke.
Edited by F1natic on Tuesday 29th December 19:41
Just having a catch up of your thread.
I recall on the Flemke thread you asking about throttle body control, I was reading recently about how the V10 BMW engine manages its 10 units, thought this may be of interest to you
https://www.rcnmag.com/garage/moon-shot
Currently visiting my partner over the holidays, and having a drive around her area so had a cheeky visit to Mr Murrays place
I recall on the Flemke thread you asking about throttle body control, I was reading recently about how the V10 BMW engine manages its 10 units, thought this may be of interest to you
https://www.rcnmag.com/garage/moon-shot
Currently visiting my partner over the holidays, and having a drive around her area so had a cheeky visit to Mr Murrays place
Edited by PAUL500 on Friday 1st January 16:09
Appreciate the link, hadn't seen the SLC using a BMW V10 and USD$11K graziano before, will be a very quick car.
The walkaround video clearly shows the old Lotus Europa vunerability, where the expensive gearbox is exposed to damage if you were careless enough to reverse into a kerb
https://www.youtube.com/watch?v=SXhkFQzSnss&t=...
The rear plexiglass looks too close to the rear cylinder inlets, good example of how compromise has to be accepted when doing things unconventionally.
Maybe the next drive could be out to Dunsfold?
The walkaround video clearly shows the old Lotus Europa vunerability, where the expensive gearbox is exposed to damage if you were careless enough to reverse into a kerb
https://www.youtube.com/watch?v=SXhkFQzSnss&t=...
The rear plexiglass looks too close to the rear cylinder inlets, good example of how compromise has to be accepted when doing things unconventionally.
Maybe the next drive could be out to Dunsfold?
Edited by F1natic on Friday 1st January 20:55
That's on the list for my next visit 
I was secretly hoping Gordon would turn up, and give me a guided tour, but it was deserted as it was New Years eve.
However we did find the famous wooden workshop at Tyrrells old factory, and I was blown away by how big Brooklands is, and its just sat there next to the road opposite a shopping centre.
Anyway I am still harbouring an F1 inspired build and have found an ideal base chassis, which is why I have started looking for an S85 to slot in the rear again, but I really must finish my other projects first
Keep those updates coming
I was secretly hoping Gordon would turn up, and give me a guided tour, but it was deserted as it was New Years eve.However we did find the famous wooden workshop at Tyrrells old factory, and I was blown away by how big Brooklands is, and its just sat there next to the road opposite a shopping centre.
Anyway I am still harbouring an F1 inspired build and have found an ideal base chassis, which is why I have started looking for an S85 to slot in the rear again, but I really must finish my other projects first
Keep those updates coming
F1natic said:
Appreciate the link, hadn't seen the SLC using a BMW V10 and USD$11K graziano before, will be a very quick car.
The walkaround video clearly shows the old Lotus Europa vunerability, where the expensive gearbox is exposed to damage if you were careless enough to reverse into a kerb
https://www.youtube.com/watch?v=SXhkFQzSnss&t=...
The rear plexiglass looks too close to the rear cylinder inlets, good example of how compromise has to be accepted when doing things unconventionally.
Maybe the next drive could be out to Dunsfold?
I can't imagine how much power the filters will be costing.The walkaround video clearly shows the old Lotus Europa vunerability, where the expensive gearbox is exposed to damage if you were careless enough to reverse into a kerb
https://www.youtube.com/watch?v=SXhkFQzSnss&t=...
The rear plexiglass looks too close to the rear cylinder inlets, good example of how compromise has to be accepted when doing things unconventionally.
Maybe the next drive could be out to Dunsfold?
Edited by F1natic on Friday 1st January 20:55
I finally got around to listening to the Chris Harris podcast with GM from a few months back, it was really interesting to hear his path through life. I really admire his ability to stick with a vision and get the result across the line - I actually learned a lot from doing the virtual tour of the other vehicles on display in the exhibition. It's said you "should never meet your heroes", which for me is easy as the majority are deceased (John Britten, Peter Brock, Bruce Mclaren, Denny Hulme) so Gordon and Greg Murphy are the only real chances on my list. GM's willingness to help look for a lost cat is an excellent indicator of true character.
Thanks for posting those shots Paul, I like the humble shed that Tyrrell used, reminds me of the old wooden workshop bench that Ferruccio Lamborghini first used, that used to be on display at the factory showroom in St Agata.
Thanks for posting those shots Paul, I like the humble shed that Tyrrell used, reminds me of the old wooden workshop bench that Ferruccio Lamborghini first used, that used to be on display at the factory showroom in St Agata.
Edited by F1natic on Saturday 2nd January 22:51
August 2019 I was hoping to get the design detailing to the stage where I could get the build approval from the NZ low volume vehicle association (4B). It is not mandatory but is highly recommended for a straight run through compliance inspections. The more upfront design that has been reviewed and passed by the technical committee the easier it is for my certifier to rubber stamp the build. Things changed a bit on the design front too, now using the C7 gearbox and diff. I was only expecting the work to take a few months but then 2020 happened and priorities shifted.
Over the next few weeks I am using the summer holidays to finish the appendices for the application, hence the dummy wheels to check proposed geometry. A lot of adjustment is built in, but everything has limits.
This is a tight budget build so it will take a long time to complete, however should see some real progress over the next few months and the test mule rolling early next year.
Over the next few weeks I am using the summer holidays to finish the appendices for the application, hence the dummy wheels to check proposed geometry. A lot of adjustment is built in, but everything has limits.
This is a tight budget build so it will take a long time to complete, however should see some real progress over the next few months and the test mule rolling early next year.
normalbloke said:
So, can anyone summarise? We’ve got 12 pages on the thread, has the o/p started it yet?
This is a bit of a douchey comment. This isn't a hit and run project thread with no details, this is an amazingly detailed build thread and one of the best on PH in my opinion.No-one is obliged to summarise for you, F1anatic updates this thread constantly, either read the posts or GTFO
PAUL500 said:
Watched that last night, the normal VR10 would be beautiful in a Lotus 49 type replica.Very interesting development, thanks for the link. The BRM H16 is a classic cautionary tale to learn from, complexity can multiply design faults.
I often reflect on why the hell am I doing all this work when it could end up being another expensive failure. I really enjoy the design side of the project, but the overall goal is to have a reliable, safe and fun road car that is reasonable to maintain and run, so why do I need 2 engines? And it always comes down to the throttle response. There is no replacement for cubic displacement, and huge torque is what will make the car feel breathtaking to drive. I have always preferred a deep bellow to a high pitch wail from a roadcar engine.
I am very mindful that the cost of development should not exceed the cost of a decent "sensible" sports car like a 911 or an Elise (both ideal for NZ conditions) or the new corvette C8. Overcomplication is a big trap and goes counter to the project goals, anything too extreme or untested has the potential to open multiple cans of expensive worms, which is typically what stalls progress.
It helps to stay focused on the end goal, the final day at the compliance office in 2024. Initially I know driving the car will not be enjoyable, because every noise will be new and I will hypersensitive to anything odd sounding. But once some miles are under the belt and it proves to be trustworthy I will be able to relax and clock up some big miles on it, it is a car I expect to put in my will. I will be very happy if it can accelerate faster than is comfortable, corner in a balanced and stable manner regardless of road surface, stop telepathically and be a comfortable long distance experience for driver and passengers - a true supercar.
I am contemplating once the car is certified to offer it for hire as a driving experience in the south Island, as hopefully by that time the world can get back on its feet and international travel will not be so restricted. We could all do with something to look forward too, don't you think?
I often reflect on why the hell am I doing all this work when it could end up being another expensive failure. I really enjoy the design side of the project, but the overall goal is to have a reliable, safe and fun road car that is reasonable to maintain and run, so why do I need 2 engines? And it always comes down to the throttle response. There is no replacement for cubic displacement, and huge torque is what will make the car feel breathtaking to drive. I have always preferred a deep bellow to a high pitch wail from a roadcar engine.
I am very mindful that the cost of development should not exceed the cost of a decent "sensible" sports car like a 911 or an Elise (both ideal for NZ conditions) or the new corvette C8. Overcomplication is a big trap and goes counter to the project goals, anything too extreme or untested has the potential to open multiple cans of expensive worms, which is typically what stalls progress.
It helps to stay focused on the end goal, the final day at the compliance office in 2024. Initially I know driving the car will not be enjoyable, because every noise will be new and I will hypersensitive to anything odd sounding. But once some miles are under the belt and it proves to be trustworthy I will be able to relax and clock up some big miles on it, it is a car I expect to put in my will. I will be very happy if it can accelerate faster than is comfortable, corner in a balanced and stable manner regardless of road surface, stop telepathically and be a comfortable long distance experience for driver and passengers - a true supercar.
I am contemplating once the car is certified to offer it for hire as a driving experience in the south Island, as hopefully by that time the world can get back on its feet and international travel will not be so restricted. We could all do with something to look forward too, don't you think?
The 4B document requires clear detail of the engine mount brackets, complicated in this case by wanting to have the subframe easily detached. Design goal is to have good loadpaths from the engine mount to the spaceframe that do not induce undue torsion into the tubes, reducing canterlevered offsets helps significantly. Some tube relocation on this front allowed fuel tank capacity to grow 2 litres (67 total).
The pictures below show the layout of the central main bracket which has to withstand 20G loading in the case of a frontal collision - i.e. withstand 88KN without failure. The brackets can yield (but must not shear off), as the vehicle is not expected to be driveable after a 20G crash but the engines must not shift towards the occupants.
The engine assembly remains fixed to the rear subframe tubing after the main bolt is removed due to the sleeve shown. The transaxle is retained on the OEM mounts at the rear crossbeam of the subframe.
Spaceframe side;
Subframe side:
The pictures below show the layout of the central main bracket which has to withstand 20G loading in the case of a frontal collision - i.e. withstand 88KN without failure. The brackets can yield (but must not shear off), as the vehicle is not expected to be driveable after a 20G crash but the engines must not shift towards the occupants.
The engine assembly remains fixed to the rear subframe tubing after the main bolt is removed due to the sleeve shown. The transaxle is retained on the OEM mounts at the rear crossbeam of the subframe.
Spaceframe side;
Subframe side:
F1natic said:
Very interesting development, thanks for the link. The BRM H16 is a classic cautionary tale to learn from, complexity can multiply design faults.
I often reflect on why the hell am I doing all this work when it could end up being another expensive failure. I really enjoy the design side of the project, but the overall goal is to have a reliable, safe and fun road car that is reasonable to maintain and run, so why do I need 2 engines? And it always comes down to the throttle response. There is no replacement for cubic displacement, and huge torque is what will make the car feel breathtaking to drive. I have always preferred a deep bellow to a high pitch wail from a roadcar engine.
I am very mindful that the cost of development should not exceed the cost of a decent "sensible" sports car like a 911 or an Elise (both ideal for NZ conditions) or the new corvette C8. Overcomplication is a big trap and goes counter to the project goals, anything too extreme or untested has the potential to open multiple cans of expensive worms, which is typically what stalls progress.
It helps to stay focused on the end goal, the final day at the compliance office in 2024. Initially I know driving the car will not be enjoyable, because every noise will be new and I will hypersensitive to anything odd sounding. But once some miles are under the belt and it proves to be trustworthy I will be able to relax and clock up some big miles on it, it is a car I expect to put in my will. I will be very happy if it can accelerate faster than is comfortable, corner in a balanced and stable manner regardless of road surface, stop telepathically and be a comfortable long distance experience for driver and passengers - a true supercar.
I am contemplating once the car is certified to offer it for hire as a driving experience in the south Island, as hopefully by that time the world can get back on its feet and international travel will not be so restricted. We could all do with something to look forward too, don't you think?
Aaargh! Noooooooo! It wouldn't last a month. I often reflect on why the hell am I doing all this work when it could end up being another expensive failure. I really enjoy the design side of the project, but the overall goal is to have a reliable, safe and fun road car that is reasonable to maintain and run, so why do I need 2 engines? And it always comes down to the throttle response. There is no replacement for cubic displacement, and huge torque is what will make the car feel breathtaking to drive. I have always preferred a deep bellow to a high pitch wail from a roadcar engine.
I am very mindful that the cost of development should not exceed the cost of a decent "sensible" sports car like a 911 or an Elise (both ideal for NZ conditions) or the new corvette C8. Overcomplication is a big trap and goes counter to the project goals, anything too extreme or untested has the potential to open multiple cans of expensive worms, which is typically what stalls progress.
It helps to stay focused on the end goal, the final day at the compliance office in 2024. Initially I know driving the car will not be enjoyable, because every noise will be new and I will hypersensitive to anything odd sounding. But once some miles are under the belt and it proves to be trustworthy I will be able to relax and clock up some big miles on it, it is a car I expect to put in my will. I will be very happy if it can accelerate faster than is comfortable, corner in a balanced and stable manner regardless of road surface, stop telepathically and be a comfortable long distance experience for driver and passengers - a true supercar.
I am contemplating once the car is certified to offer it for hire as a driving experience in the south Island, as hopefully by that time the world can get back on its feet and international travel will not be so restricted. We could all do with something to look forward too, don't you think?
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