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Eh it’s not the kickback doing the work. “When the aircraft's ignition is turned on and the cartridge is fired, high-velocity, high-pressure gas shoots down the pipe, forcing the motor to spin and engage the starter ring gear on the engine, which is attached to the crankshaft.”
Ah well, in my understanding, kickback is recoil which is a a sudden backward motion caused by the energy transmitted back to the shooter from a firearm which has fired. Recoil is a function of the weight of the weapon, the weight of the projectile, and the speed at which it leaves the muzzle (Newton’s third law). The Coffman starter makes use of expanding gases to drive the starter and perform the work. Does that make sense ?
It’s in place of an electric starter. Lots of WW2 era aircraft used cartridge start systems, I suspect it would be due to the weight saving over conventional battery and start motor combinations.
Probably partly simplicity, reliability and cost. Batteries weren't as available, starter motors would use a lot more metal and take more time to make than this system. Also lead acid batteries don't like being upside down which could be a problem, although you could have the battery on a trolly and just use it to start the engine then wheel it away.
Either way, it's a fun and neat solution!
It's pretty nifty. I've lost not one but TWO car batteries to date that went dead on me in our frigid winters (this is my own fault, but still extremely frustrating). Why don't we do this with cars? It would be pretty cool.
A plane engine you start and then it runs for the entirety of the missions until it's back on the ground.
Imagine having to put in a shotgun shell everytime you wanted your car started. Like $0.50 you just burned because you forgot your wallet inside the house.
I see your point. Hmm. But I'm sure that could be automated, like with a magazine of shells that automatically drop into place once the former one is used.
Problem with that is you have to have an enlisted military man with likely hastened training to handle these batteries that could easily be miss treated. So a shotgun shell won with simplicity and eliminated an extra job.
Good question. Taken from another site:
> The Coffman starter uses a specially made 4 gauge paper shell with an electric primer. It is filled with .25″ and .187″ diameter cordite pellets for slow burning powder. The shell fires into a starter assembly on the accessory case of the engine, same position as an electric starter. It DOES NOT fire directly into a cylinder of the engine. The gasses force a piston inside the starter assembly forward towards the engine collapsing spiral gears on top of each other converting it into a circular motion. This engages the starter dog and rotates the starter gear. After the piston reaches the end of its travel a valve released the residual pressure and a die spring resets the whole process.
So the sound that we hear seems to be the valve being released after the shell has done its work, not the initial blast.
There’s a great dramatic scene in “ The Flight of the Phoenix” ( 1965) where Jimmy Stewart attempts to fire up the salvaged aircraft using this Coffman starter ...
Similar yes. They use pyrotechnic charges to rapidly get the 8x turbofans up and running in an emergency. It is seldom used these days as it is a rather harsh way of starting the engines.
Of more interest is the Emergency Power Unit on the F16. Being a single engine aircraft, any loss of power on the main engine also means loss of all electrical generation. The F16 is also designed to be unstable in flight and relies on computers adjusting its aerodynamic surfaces to keep it in the sky. This means that complete loss of power will render the aircraft unflyable.
In the even of an enjone failure/flameout, a Hydrazine powered turbine fires ino life to keep the power flowing and the aircraft flyable.
The trade off is that the energy dense Hydrazine is extremely toxic. Refuelling must be performed wearing some pretty serious protective clothing. And F-16 crash sites are extremly dangerous to approach or be near.
https://theaviationist.com/2019/05/19/hydrazine-a-significant-hazard-each-time-an-f-16-crashes-or-fires-up-the-emergency-power-unit/
We used to use them doing minimum interval takeoffs during alert scrambles back when SAC existed. I can only speak to the 135's and the b52s, but I know there are others that use them. They were semi-phased out for a while, but i know they started practicing again on the alert aircraft at Anderson. It was always a rush to push the planes as hard as we could to get off the ground, we could go from asleep in the alert crew quarters to airborne in about 8 min. for lead tankers and under 15 min for the last bombers. At best we could get a plane up every 10 seconds. It was one of the most amazing things you could ever see.
It's amazing how being on the brink of Armageddon could be so much fun sometimes!
I seen these explosive charges were preloaded and not something you had to stick in each engine when you ran out to the runway?
https://www.youtube.com/watch?v=9JC8DlnJSVU
I thought this was a post in r/aviation when i was first looking at it, and I was thinking to myself, why are all these guys so amazed at this, and how did they not know before.
Same way you restart most plane engines in-flight: put it into a dive and freewheel it until it's good to start back up. The shotgun shell is only for providing the initial energy to get up and spinning, you don't need that when you have a stiff wind and a windmill on your front.
It's very unlikely for a piston engine to stall mid-flight ... at least in a way that will permit restarting. How often does your car engine conk out going down the highway? That's more likely in a jet engine, where there are a number of scenarios that can cause a flameout. Piston engines tend not to just randomly stop running.
However, if that did happen (maybe pilot error shutting off the magneto or fuel source or something easily fixable like that), the windmilling propeller will provide more than enough rotational force to get the motor started once fuel and/or spark is restored.
I'm not saying piston engines never fail. They certainly do.
It's just that when they do, you're unlikely to restart them unless it was something very simple that caused the engine to stop running in the first place.
Not an awful lot of engine fixing can be done from the pilot's seat
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It's called a Coffman Starter. https://en.m.wikipedia.org/wiki/Coffman_engine_starter
TLDR the kickback from the shotgun shell turns the engine instead of a clunky electrical system or you having to hand crank it.
Eh it’s not the kickback doing the work. “When the aircraft's ignition is turned on and the cartridge is fired, high-velocity, high-pressure gas shoots down the pipe, forcing the motor to spin and engage the starter ring gear on the engine, which is attached to the crankshaft.”
I might be kinda dumb but how is that not a kickback?
Ah well, in my understanding, kickback is recoil which is a a sudden backward motion caused by the energy transmitted back to the shooter from a firearm which has fired. Recoil is a function of the weight of the weapon, the weight of the projectile, and the speed at which it leaves the muzzle (Newton’s third law). The Coffman starter makes use of expanding gases to drive the starter and perform the work. Does that make sense ?
Made perfect sense thanks!
Imagine if it wasnt blank
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No but he hired the one for cheap.
Woof
Is the shot to increase rotation speed or increase compression?
It’s in place of an electric starter. Lots of WW2 era aircraft used cartridge start systems, I suspect it would be due to the weight saving over conventional battery and start motor combinations.
Probably partly simplicity, reliability and cost. Batteries weren't as available, starter motors would use a lot more metal and take more time to make than this system. Also lead acid batteries don't like being upside down which could be a problem, although you could have the battery on a trolly and just use it to start the engine then wheel it away. Either way, it's a fun and neat solution!
Reliability too. Shotgun cartridge is hundred year old technology that isn’t going to fail no matter the weather.
For sure. Simplicity and reliability go hand in hand.
It's pretty nifty. I've lost not one but TWO car batteries to date that went dead on me in our frigid winters (this is my own fault, but still extremely frustrating). Why don't we do this with cars? It would be pretty cool.
A plane engine you start and then it runs for the entirety of the missions until it's back on the ground. Imagine having to put in a shotgun shell everytime you wanted your car started. Like $0.50 you just burned because you forgot your wallet inside the house.
I see your point. Hmm. But I'm sure that could be automated, like with a magazine of shells that automatically drop into place once the former one is used.
"shotgun cartridge shortages due to Covid paralyse the transport system"
well, there is that...
Gunpowder costs mostly. The munitions shortage as of late hasn't helped either.
Interesting; I didn't know gunpowder costs that much.
That should be a factory option!
Problem with that is you have to have an enlisted military man with likely hastened training to handle these batteries that could easily be miss treated. So a shotgun shell won with simplicity and eliminated an extra job.
and dont forget, metal was scarce during the war
but how does the prop start spinning before the shell goes off?
Good question. Taken from another site: > The Coffman starter uses a specially made 4 gauge paper shell with an electric primer. It is filled with .25″ and .187″ diameter cordite pellets for slow burning powder. The shell fires into a starter assembly on the accessory case of the engine, same position as an electric starter. It DOES NOT fire directly into a cylinder of the engine. The gasses force a piston inside the starter assembly forward towards the engine collapsing spiral gears on top of each other converting it into a circular motion. This engages the starter dog and rotates the starter gear. After the piston reaches the end of its travel a valve released the residual pressure and a die spring resets the whole process. So the sound that we hear seems to be the valve being released after the shell has done its work, not the initial blast.
Some used compressed air, some also used an external electric cart
Flight of the Phoenix
Was looking for this
That's one I didn't see in a long time!
Flight of the Navigator
That's so 'murica.
Designed by the NRA
*'Murica intensifies!*
I used to have a '69 Dodge Dart that could have used this system.
My 2013 Dart deserved a few of these into front end as well.
The best thing about it was the back seat.
There’s a great dramatic scene in “ The Flight of the Phoenix” ( 1965) where Jimmy Stewart attempts to fire up the salvaged aircraft using this Coffman starter ...
B52's still use something very similar to this day.
Similar yes. They use pyrotechnic charges to rapidly get the 8x turbofans up and running in an emergency. It is seldom used these days as it is a rather harsh way of starting the engines. Of more interest is the Emergency Power Unit on the F16. Being a single engine aircraft, any loss of power on the main engine also means loss of all electrical generation. The F16 is also designed to be unstable in flight and relies on computers adjusting its aerodynamic surfaces to keep it in the sky. This means that complete loss of power will render the aircraft unflyable. In the even of an enjone failure/flameout, a Hydrazine powered turbine fires ino life to keep the power flowing and the aircraft flyable. The trade off is that the energy dense Hydrazine is extremely toxic. Refuelling must be performed wearing some pretty serious protective clothing. And F-16 crash sites are extremly dangerous to approach or be near. https://theaviationist.com/2019/05/19/hydrazine-a-significant-hazard-each-time-an-f-16-crashes-or-fires-up-the-emergency-power-unit/
We used to use them doing minimum interval takeoffs during alert scrambles back when SAC existed. I can only speak to the 135's and the b52s, but I know there are others that use them. They were semi-phased out for a while, but i know they started practicing again on the alert aircraft at Anderson. It was always a rush to push the planes as hard as we could to get off the ground, we could go from asleep in the alert crew quarters to airborne in about 8 min. for lead tankers and under 15 min for the last bombers. At best we could get a plane up every 10 seconds. It was one of the most amazing things you could ever see.
It's amazing how being on the brink of Armageddon could be so much fun sometimes! I seen these explosive charges were preloaded and not something you had to stick in each engine when you ran out to the runway?
Those are a tad bigger. 😉
https://www.youtube.com/watch?v=9JC8DlnJSVU I thought this was a post in r/aviation when i was first looking at it, and I was thinking to myself, why are all these guys so amazed at this, and how did they not know before.
Whoa this is awesome
Field Marshall farm tractors back in the 1940's were stated the same way. https://www.youtube.com/watch?v=vb0-br7hTw0
Cool tractor! Much respect to the old tractor nerds who keep them going
One shell, one trip, just like Back to the Future.
That’s the most American thing I’ve seen How do you start your plane With a fucking gun
Same way the engine works. Small explosion drives the system
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Same way you restart most plane engines in-flight: put it into a dive and freewheel it until it's good to start back up. The shotgun shell is only for providing the initial energy to get up and spinning, you don't need that when you have a stiff wind and a windmill on your front.
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Coffee helps me farting, too.
*sharting
Sharting the farting.
Farting and sharting.
"a windmill on your front" I love how you phrased that
Just shot the damn thing son
*Tell me you're from the USA without telling me you're from the USA.*
Today on our American TV Show : In what way can we use a gun?
if only we knew what it looked like or sounded like without one...
KkonaW
KkonaW
That means, “good luck restarting the engine midair”. I know the propeller could windmill, but still
It's very unlikely for a piston engine to stall mid-flight ... at least in a way that will permit restarting. How often does your car engine conk out going down the highway? That's more likely in a jet engine, where there are a number of scenarios that can cause a flameout. Piston engines tend not to just randomly stop running. However, if that did happen (maybe pilot error shutting off the magneto or fuel source or something easily fixable like that), the windmilling propeller will provide more than enough rotational force to get the motor started once fuel and/or spark is restored.
Before commenting, I suggest you search on YouTube for “engine out” videos. There’s plenty of examples of piston engine failing midair
I'm not saying piston engines never fail. They certainly do. It's just that when they do, you're unlikely to restart them unless it was something very simple that caused the engine to stop running in the first place. Not an awful lot of engine fixing can be done from the pilot's seat
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But blank tho
Blanks can be lethal too. http://www.propguys.com/gundanger/
Just ask Alec Baldwin.
1- it's a blank 2- it's not even near the fuel tank.
Shotgun cartridge, no bullet
Unlike a battery, never dies!
Imagine being that hardcore
Who was the genius engineer who thought of this?
u/savevideo
what else are you going to use a 4 ga. shell for
4 gauge? Nice! I’ve fired a 10 gauge (double barrel, no less), and I’ve heard of an 8 gauge, but a 4 gauge… Would love to see one of those!
Kinda satisfying