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View Full Version : This is the result of too much free time and a wild imagination



Al_C
11-16-2022, 09:40 PM
I'm going to regret this, but what the heck. Thanks to another time-waster on facebook, I found a youtube video about some guy in Michigan who put a Westinghouse J34 turbojet on a pontoon boat. A part of me thinks he's nuts, but another part of me thinks this is really cool. So I got to thinking, has anyone ever tried to put a jet engine in a cobra? I wasted another 30 minutes looking for that. No luck.

But why not? Why couldn't you put a Westinghouse J34 or a Pratt J57 or some other early jet engine on a Cobra? First thought is fit. It might be tight. So, while I'm driving around town, I'm thinking about this. Darn near missed a turn!

Bottom line: there are folks who will think I am certifiably crazy. There are others who will think I have too much time on my hands. Then there are others who will say "why not!" and take up the challenge. The ones I'm really looking for are those who have the time, money and skills to pull this off...

The issues I see are fit-related. An early stage (i.e. 1940s-1950s) jet is roughly 2.5 feet wide and more than 6 feet long. Where is that going to go in a cobra? Passenger seat? No, we need that. But..... what if we separate the jet so the compressor section is in the traditional engine bay and the burn cans and turbine are behind the cockpit? You'd have to break apart the jet and do a lot of custom plumbing to get the compressed air through the cockpit, you'd have to have a compressor drive shaft running through the cockpit, but it, conceptually, is feasible. Or not. You tell me.

A small turbojet would be more than sufficient to power one of these cars. OK - it's nuts. But why not? Anybody want to comment?

Namrups
11-16-2022, 09:51 PM
What about a turbine like the one Chrysler used in its turbine car? Basicly the same thing.

racingandfishing
11-16-2022, 09:54 PM
Seems relevant to both the post and the time of year!

174989

J R Jones
11-16-2022, 10:33 PM
A J57 is excessive. This is the engine used in the B52 with water injection and in fighters with afterburner.
The J57 is over 3 feet in diameter, 17.5 feet long and weighs 5052 lbs.
It develops 10,000 lb thrust at full military and 16,500 lbs thrust in afterburner.
One would not have to corner to challenge the anti roll bars.

Getting serious you could install the J58 from the SR71 Blackbird.
4 feet in diameter, 15 feet long and weighs 6000 lbs.
It develops 32,500 lb thrust.
The variable cone inlet is happiest at 3.2 mach which would challenge MK IV Roadster aerodynamics.
jim

rthomas98
11-16-2022, 10:35 PM
Hey why not. Some crazy put a jet engine in a smart car. https://www.youtube.com/watch?v=h6hAoAvdZjY

Al_C
11-16-2022, 10:51 PM
OK, my bad on the J57. But if you can put a jet in a smart car...

Enough of this nonsense. Thanks for humoring me. Or, just carry on with the conversation!

Nigel Allen
11-17-2022, 03:51 AM
I could imagine Shelby would be rolling in his grave, but it would only be to face you with a big grin and a thumbs up.

john42
11-17-2022, 07:41 AM
Heh.... I was thinking a Bugatti W16 would be a cool pick for a Cobra engine as well :-)

J R Jones
11-17-2022, 12:44 PM
Hey why not. Some crazy put a jet engine in a smart car. https://www.youtube.com/watch?v=h6hAoAvdZjY

I did not see an actual speed run in that video, but he did have numbers. Beyond power and RPM sitting next to a 900F engine is intimidating.

In my former development life I did an engine mount project with Lord in Erie PA. Having beers after work the Lord guys described a jet engine mount project that went catastrophic.
They were running a 747 airliner engine in a vertical dyno cell, ducted inlet and exhaust out the top. Test monitor cells were stack/staged along the sides.
At high operating RPM an engine failure imposed load transfer from the spinning bits to the stationary bits. The engine mounts tore loose and the outer housing started spinning, severing all connections.
Despite the exhaust the engine climbed the dyno cell and exited out the top. The energy was still substantial as it spun into the parking lot taking out 20 cars and a couple of buildings.
I expect that the toilet paper rolls were spinning after that.
jim

Dgc333
11-17-2022, 01:31 PM
Take a trip to your local drag strip when they are having a "Jet Cars Under the Stars" show and then decide if this makes sense.

drewr
11-17-2022, 02:17 PM
You could use a Pratt and Whitney Canada PT6 turboprop engine like the Lotus 56.175024

Ducky2009
11-17-2022, 04:06 PM
Honda makes a small corporate jet plane. You could easily pick up the engine, 400 lbs without the blades on it. Problem would be, you'd need a direct drive attachment... and it turns an extremely high RPM.
HF120 = 2,000 lbs of thrust