Just read in a Swedish Magazine that Kirkham are building Cobra Chassis in Aluminum in the Polish city of Mielec. The same factory also makes Black Hawk helicopters. Both 289 and 427 street and race cars are being built.
Texas Swede
Oh Boy! "Vintage" racing Cobras will show up with a lighter chassis to go with their "in period" 363cid engines, Jerico gears and aluminum Salisburys. Gotta preserve that history. LOL
Where have you been? This "news" is as old as the Kirkham itself. Now to really burst your bubble the Shelby Cobra continuation cars are from Kirkham. It's amazing how much a little CSX tag adds to the asking price.
Quote from: 98SVT - was 06GT on May 14, 2021, 05:24:25 PM
Where have you been? This "news" is as old as the Kirkham itself. Now to really burst your bubble the Shelby Cobra continuation cars are from Kirkham. It's amazing how much a little CSX tag adds to the asking price.
Yes but not in aluminum chassis ;) . Aluminum bodywork yes . Aluminum chassis not so much. Vern has a Kirkham with a stainless steel chassis in his shop to sell now.
Other than the coolness factor, does the stainless provide any benefits over regular steel, in a Cobra?
Quote from: Side-Oilers on May 14, 2021, 06:15:29 PM
Other than the coolness factor, does the stainless provide any benefits over regular steel, in a Cobra?
I would think it's a disadvantage. The reason being, stainless is on the brittle side and doesn't like to flex. As a result in an area of the chassis where mild steel would flex, stainless will eventually crack.
I haven't heard about aluminum chassis before? When did this come about? A Cobra is already at the 2,300 pound level, the aluminum bodies weighing in at 30 pounds or so according to some analytic journalists in the past.
Aluminum is not the material of choice for a chassis.
Quote from: shelbydoug on May 14, 2021, 06:42:39 PM
Quote from: Side-Oilers on May 14, 2021, 06:15:29 PM
Other than the coolness factor, does the stainless provide any benefits over regular steel, in a Cobra?
I would think it's a disadvantage. The reason being, stainless is on the brittle side and doesn't like to flex. As a result in an area of the chassis where mild steel would flex, stainless will eventually crack.
I haven't heard about aluminum chassis before? When did this come about? A Cobra is already at the 2,300 pound level, the aluminum bodies weighing in at 30 pounds or so according to some analytic journalists in the past.
Aluminum is not the material of choice for a chassis.
+1. At the very least you would have to substantially beef up the tube wall thickness to maintain the same strength of steel.
The aluminum chassis is "Billet", not aluminum round tube rails.
Yes, been at it for a long, long time. David and crew are the tops
Bill
I think the stainless chassis is about the coolness factor . Kirkham is always doing engineering exercises if a customer is willing to pay. Bronze or Copper bodywork, billet aluminum control arms etc.
Shelby did the Series I chassis in aluminum.
Well if you are talking solid aluminum shapes as "billet", I'd have to see the weight savings over steel tube. I don't see where that's possible.
I suppose it depends on the alloy used?
I can also show you strength of materials properties of aluminum v. mild steel that makes an aluminum chassis questionable and basically for show. However, that is purely academic anyway.
If you told me titanium, then I'd believe that.
The Mk IV GT40's had a honeycomb chassis (tub) that were "epoxied together". The car weighed more then the MK II's. The welds on the aluminum outriggers were a work of art.
I only saw one close up. The one that George Stauffer had. Very labor intensive of a build but admittedly very seductive and hypnotic to ogle at. ;D
I would think a carbon fiber "tub" like the Alfa 4c uses would be the way to go but I don't see how that could apply to a "Cobra" chassis but maybe I'm short of imagination?
Maybe the aluminum billet chassis is built like an airplane wing which supports in some cases over 100 ton loads?
Interesting subject.
Quote from: shelbydoug on May 14, 2021, 08:18:45 PM
The Mk IV GT40's had a honeycomb chassis (tub) that were "epoxied together".
The J Car was held together with just epoxy and broke up. After the death of Ken Miles the new chassis for the MKIV was epoxied and riveted together with plates at the junctions. The honeycomb aluminum is some neat stuff but hard to work with. I have some left over from when the BD10 jet project got scrapped and have used it for a few little projects. You need to drill through both sides insert and epoxy a tube in for the bolts to go through or you'll crush it.
The billet aluminum chassis still isn't news Larry Ellison bought the first one many years ago - all it took was cubic dollars. http://www.kirkhammotorsports.com/book_aoe/
You can download the whole book in PDF and see what a major undertaking it was. Or if you prefer ante up some bucks.
Amusingly, the entire process was carefully documented and collected in a book, but not just any book. The documentation of such a car should have a certain craftsmanship to it as well, cue 35 lbs of aluminum billet being machined into book form, the back covered in leather and presented to the owner along with the car. While it's available in extremely limited supply, the $4,500 price will keep most away.
As far as aluminum strength goes there are many torch welded 1960s aluminum tube frame race cars still running around England. If you take a look under any newer Ford GT or Corvette and many other cars you'll see aluminum control arms, drive shafts etc. Also stainless is not brittle unless it has been heat treated to that state. There are many alloys of it for various jobs - some of it will even rust depending on it's content of alloys. It's easy to cut and weld but a PIA to machine.
When we built the Pantera Mega Buck we used Titanium for the control arms and even the roll bar. It was for showing that the owner had money no other reason. Same reason that we spent $40,000 buying a sheet of Inconel and having it made into tubing for the exhaust system. We even got a visit from the feds wondering what we were using, what at the time was, a restricted material for.
Hall Pantera has been selling "billet aluminum" Pantera suspension a-arms for years. Two mentions of note on that. 1) they are heavier then the original steel tube arms 2) they are known to bend and crack through the "bends". I don't know what alloy he used, so don't ask please.
They are beautiful to look at but I wouldn't do endurance racing with them.
It really isn't a criticism by me. Engineering can be aimed at a solution to a specific "problem" but is limited sometimes by the vision of the criteria that is set. BUT if plan A doesn't work then go to plan B, whatever that may be? ;)
Some solutions when examined can be questionable but don't blame the finished product, blame the criteria. The Soviet Mig 14 Mig-25? that defected to the West (Japan?) years ago is somewhat of an example.
It was a plane that had Western military analysts "concerned" about and when it showed up constructed of sheet steel rather then titanium there was some relief. Not being an analyst (anal being the significant root of that word) I can't state how relieving that all was?
Again, I'm not arguing because it isn't my field of expertise. I find the subject intriguing and I don't want the FBI or even the ATF pushing in the door to see why the neighbors are complaining about me?
I found it "concerning" that I received a waiver certificate with my first set of titanium Cleveland valves years ago. I don't see them coming with that any more and my shotguns are all at least 18" long.
Is this a picture of you with the Iconel Pantera? "Contour Mike" is son #1 as Charlie Chan might say. It looks just like him and I used to tease him about where he would go at night? ;)
As far as the J car/Miles goes, it's my understanding that the most recent speculation of the "Incident" is that the rear locked up. People that I know that worked for Holman-Moody all say NO ONE knows what happened with that car because it completely disintegrated, so while the honeycomb coming apart is a highly educated guess, it's still speculation scientifically.
Nick Soprano, Classic Motor Cars, then in North White Plains, NY, owned I think "chassis" J-6. When I saw it, it was already in MK IV configuration and in the showroom.
With a car like that, who is left alive that can tell me what is original and what is fictional? That was 20 years ago and he moved to Mt.Kisco. I haven't been there since.
Here I am, at Nick Soprano's with the GT40 inside, window shopping for his Mangusta at the time. It was only $25,000. Who knew? No pictures of the "MkIV that day. Place was locked up.
See, being a fly on the wall with a camera makes some interesting life highlights?
;D
Don't talk about welding to me. I still have nightmares about welding 6" hull plates together and setting myself on fire? I had a friend who's father worked for Grumen on LI in the '70s. I don't know how big his lunch "pail" was but if I needed -32 Aeroquip, I'd call him. The stuff that he had as "scrap" was amazing...and probably illegal, but...
Personally, I'd stay with the original concepts of the chassis. If I wanted something "Star Wars", there are a bunch already made and field tested as "reasonably safe" even if by some "nutzie Formula 1 drivers" on the street. 8)
I don't care that the Polish guys were Soviet Mig builders in a past life. They built that steel Mig. Vodka is popular in Poland too.
I "ain't Chuck Yeager"!
Quote from: shelbydoug on May 15, 2021, 07:13:54 AM
Some solutions when examined can be questionable but don't blame the finished product, blame the criteria. The Soviet Mig 14? that defected to the West (Japan?) years ago is somewhat of an example.
It was a plane that had Western military analysts "concerned" about and when it showed up constructed of sheet steel rather then titanium there was some relief. Not being an analyst (anal being the significant root of that word) I can't state how relieving that all was?
Actually, that MiG was a MiG-25, Foxbat. And yes, it was it did land in Japan on September 6, 1976, piloted by Viktor Belenko who was defecting to the West. When the US got a look at it, they were surprised to find that it was largely made of stainless steel. When it was returned to the Soviet Union, it was in a state of disassembly. The concern was that the Mig-25 was fast enough to intercept the hordes of B-70 bombers and F-12 interceptors the US would be sending over the Soviet Union. Of course only two XB-70s and three YF-12s were ever built. So much for the hordes.
Quote from: shelbydoug on May 15, 2021, 07:13:54 AM
As far as the J car/Miles goes, it's my understanding that the most recent speculation of the "Incident" is that the rear locked up. People that I know that worked for Holman-Moody all say NO ONE knows what happened with that car because it completely disintegrated, so while the honeycomb coming apart is a highly educated guess, it's still speculation scientifically.
Basic aluminum honeycomb is incredibly strong. The actual core (the honeycomb) has a sheet of aluminum skin bonded to either side of it. A one inch cross section has very little weight. In order to fasten anything to it and make it removable, a threaded insert is bonded into the honeycomb. It is unlikely that the honeycomb itself failed by disintegration (e.g the faces peeling away from the core). Rather it would be more likely that the failure occurred where the honeycomb was joined to some other part.
Well, I got 90% of it right? That's still an A. After all it was only 45 years ago and meant little to me?
Now if I can only remember where I left my car keys?
Quote from: shelbydoug on May 15, 2021, 09:31:26 AM
Now if I can only remember where I left my car keys?
Uh, right next to the toothpaste?
The Mega Buck Pantera has a twin turbo SOHC Cammer. Last I heard it's in a private collection on the eastern seaboard. I forget what Shelby American it's in. The engine compartment was the back cover.
Nobody knows if the J Car broke up before or during the crash - only that the epoxy connections failed. The MKIV also had a steel roll cage added to it.
The YF12 was basically an armed 2 seat SR71. They still fly a SR71 modified with 2 seats (it was the trainer for pilots with an instructor) at Edwards as a chase plane for really fast experimental stuff. A guy I know had them fly a wing section he designed on it to watch the air flow. They have a pylon on the plane and mount a scale section of the wing to it. It's painted with some magic paint that changes color as the pressure on it changes. They film it at speed and watch the pressure wave flow along it. The A 12 was the prototype of the design and had an aluminum skin. The extreme heat that the friction of the air caused ruined the temper in the aluminum skin. They went to a titanium skin because it would take the heat. All the parts for those planes were tracked at each step by Lockheed. One of the forgings was cracking. They found the ones that cracked had been machined during the summer and traced it to the fact that Burbank water had more chlorine in it during the summer. They started using distilled water for their cutting tool coolant. There is an A12 and SR71 at Blackbird Park in Palmdale CA. The sole remaining YF12 is at Wright-Patterson. https://www.google.com/maps/search/spy+plane+park+palmdale+ca/@34.6030021,-118.08684,177m/data=!3m1!1e3?hl=en
BTW: The B2 was built in the Ford Pico Rivera, CA assembly plant. Northrop bought the place from Ford and built all the parts there then trucked the pieces to Palmdale for assembly. Today it's a shopping center.
Billet will never have the pound per pound strength of a forging. When you forge something you force the grain structure into alignment. When you cut something out of a block you end up cutting through the grain structure and building in weak points. Casting a part will help the grain structure align but still isn't as strong/dense as a forged part.
When someone tells me the chassis is aluminum on a Cobra, I'm not thinking of suspension components like a-arms, forged or not. I'm thinking that the main tubes are aluminum.
Forged aluminum a-arms are nothing new. They've been around since the '60s.
I'd suspect that Kirkham sourced them from something like Porsche or Corvette and just built chassis uprights to accept them.
289 Cobras with their 3" mild steel tube frames were often tweaked or twisted by the torque of the engine. 4" tubes were ordered for the 427 coil spring chassis.
What alloy of aluminum would be needed to replace the steel tube frames?
Considering the Hall Pantera billet a-arms being heavier then the original steel, I can't help but extrapolate that to a Cobra chassis and if that is the case would wonder why anyone would bother?
Quote from: 98SVT - was 06GT on May 15, 2021, 01:14:16 PM
Nobody knows if the J Car broke up before or during the crash - only that the epoxy connections failed.
Agreed.
Quote from: 98SVT - was 06GT on May 15, 2021, 01:14:16 PM
The A 12 was the prototype of the design and had an aluminum skin. The extreme heat that the friction of the air caused ruined the temper in the aluminum skin. They went to a titanium skin because it would take the heat. All the parts for those planes were tracked at each step by Lockheed. One of the forgings was cracking. They found the ones that cracked had been machined during the summer and traced it to the fact that Burbank water had more chlorine in it during the summer. They started using distilled water for their cutting tool coolant. There is an A12 and SR71 at Blackbird Park in Palmdale CA. The sole remaining YF12 is at Wright-Patterson.
Actually, the A-12 was a single seat fully operational CIA spy plane, 13 were built. It eventually evolved into the SR-71. I believe that two A-12s were modified as two seat M-21 motherships for the D-21 spy drone. They lost one testing the drone when it hit one of the vertical fins of the mothership during launch (https://www.youtube.com/watch?v=GMyC2urCl_4). The backseater died when he landed in the water after ejecting and opened his helmet face plate and his suit filled with water. D-21 drones are on display at both Pima Air & Space (Tucson) and Museum of Flight (Seattle). One additional item was that the major supplier of titanium was the Soviet Union. The CIA set up several dummy companies in order to obtain sufficient quantities for the program. Ironic isn't it that the Russians supplied the main material needed to spy on them...
Quote from: 98SVT - was 06GT on May 15, 2021, 01:14:16 PM
Billet will never have the pound per pound strength of a forging. When you forge something you force the grain structure into alignment. When you cut something out of a block you end up cutting through the grain structure and building in weak points. Casting a part will help the grain structure align but still isn't as strong/dense as a forged part.
Yup, that's the secret, aligned gain structure. Everybody is rowing in the same direction.
Quote from: shelbydoug on May 15, 2021, 04:34:51 PM
When someone tells me the chassis is aluminum on a Cobra, I'm not thinking of suspension components like a-arms, forged or not. I'm thinking that the main tubes are aluminum.
Forged aluminum a-arms are nothing new. They've been around since the '60s.
I'd suspect that Kirkham sourced them from something like Porsche or Corvette and just built chassis uprights to accept them.
289 Cobras with their 3" mild steel tube frames were often tweaked or twisted by the torque of the engine. 4" tubes were ordered for the 427 coil spring chassis.
What alloy of aluminum would be needed to replace the steel tube frames?
Considering the Hall Pantera billet a-arms being heavier then the original steel, I can't help but extrapolate that to a Cobra chassis and if that is the case would wonder why anyone would bother?
A Larry Ellison (CEO of Oracle) commissioned the "billet cobra build"
(https://i.pinimg.com/originals/3f/36/25/3f3625bed148549f4a4389bd4568d97d.jpg)
I'd love to know the weight of that chassis. That's billet aluminum alright.
One of the Drones is also at Blackbird Park in Palmdale https://www.google.com/maps/@34.6029467,-118.0854763,3a,42.6y,267.86h,83.87t/data=!3m6!1e1!3m4!1skPXL4B_qd7aSIfqUjg_eLw!2e0!7i16384!8i8192?hl=en
All the answers to the billet Cobra Chassis are here - it's well worth the read: http://www.kirkhammotorsports.com/book_aoe/
Quote from: 98SVT - was 06GT on May 15, 2021, 08:26:39 PM
One of the Drones is also at Blackbird Park in Palmdale https://www.google.com/maps/@34.6029467,-118.0854763,3a,42.6y,267.86h,83.87t/data=!3m6!1e1!3m4!1skPXL4B_qd7aSIfqUjg_eLw!2e0!7i16384!8i8192?hl=en
All the answers to the billet Cobra Chassis are here - it's well worth the read: http://www.kirkhammotorsports.com/book_aoe/
You weren't kidding.Who would have thought.