Armed Polite Society
Main Forums => The Roundtable => Topic started by: 230RN on August 11, 2017, 03:35:08 PM
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https://youtu.be/65qrzgbTTcQ
(Watch your sound level.)
A lot of engines, including for tractors, etc. were started this way.
I always wondered what the details of that shotgun starting operation was, and this video shows it.
Terry, 230RN
MORE (Old diesel with "glow plug." Orange hammer is a prerequisite):
https://youtu.be/vb0-br7hTw0
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Prop driven fighters had a shotgun starter as a backup if
when the electrics failed out on some godforsaken Pacific island. Pretty darned effective, actually.
For more oddball starter history..
Air
https://www.youtube.com/watch?v=R6Lg4xHHkd8
Inertia
https://www.youtube.com/watch?v=3zXkVQnVmuo
Pony Motor
https://www.youtube.com/watch?v=drAgUv41CNI
And just for grins, a really neat sound during an industrial electric motor soft start
https://www.youtube.com/watch?v=vWwiLOdkCgc
Brad
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Some jets used cartridge start too.
Sent from my SM-G955U using Tapatalk
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Cool stuff, gents. Thanks for sharing.
Went to Planes of Fame in Chino one time in '77 just before I finished my hitch in the service. A buddy and I stumbled across an airshow there on our way to LA for the weekend. We never made it to LA.
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I'm wondering if the pellets get blown out the exhaust, or do they just rattle around in the cylinder.
=D
Edited to add big grin.
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I'm wondering if the pellets get blown out the exhaust, or do they just rattle around in the cylinder.
I'm guessing it'd be a special shell.
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Prop driven fighters had a shotgun starter as a backup if when the electrics failed out on some godforsaken Pacific island. Pretty darned effective, actually.
For more oddball starter history..
Air
https://www.youtube.com/watch?v=R6Lg4xHHkd8
Inertia
https://www.youtube.com/watch?v=3zXkVQnVmuo
Pony Motor
https://www.youtube.com/watch?v=drAgUv41CNI
My Dad's old John Deere model 70 has a pony motor.
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I'm guessing it'd be a special shell.
It is indeed. Reading up on it the shell was filled chock full of slow burning powder.
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I'm gonna go back and put a smiley in there.
It is indeed. Reading up on it the shell was filled chock full of slow burning powder.
Any more details on that? Link? I was kinda wondering how they sealed it with that shiny stuff --- combustible cellulose nitrate "overshot" wad?
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I'm gonna go back and put a smiley in there.
Any more details on that? Link? I was kinda wondering how they sealed it with that shiny stuff --- combustible cellulose nitrate "overshot" wad?
https://en.wikipedia.org/wiki/Coffman_engine_starter
"large blank cartridge loaded with cordite"
has diagrams -
http://oppositelock.kinja.com/dont-like-hand-cranking-your-engine-use-a-shotgun-1662680233
Looks like it's completely filled with powder, just has a cardboard cap to keep everything in.
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^ Very interesting, especially the Canberra jet start.
Boomhaur noted that: "Some jets used cartridge start too." Interesting to see the actual operation.
Muy Danke !
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^ Very interesting, especially the Canberra jet start.
Boomhaur noted that: "Some jets used cartridge start too." Interesting to see the actual operation.
Muy Danke !
The B52 is capable of cartridge start. Turns an operation that takes nearly an hour to get all the engines started into a 10 minute operation.
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An hour to start a B-52? Wow. For that matter, how long does it take to start a modern commercial jet?
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An hour to start a B-52? Wow. For that matter, how long does it take to start a modern commercial jet?
Turns out that I remembered more conservatively, it's actually MORE than an hour, then less than 10 minutes with the cartridges.
https://www.youtube.com/watch?v=anFdf5aYtIA
"The charges basically jumpstart the engines, removing the need to bring out the aerospace ground equipment used on normal launches," said Tech. Sgt. Andrew Poole, 36th EAMXS crew chief. "By removing these steps we increase the aircrafts startup time from more than an hour to less than 10 minutes."
The plane has 8 engines. Once one is started, it's capable of starting the rest itself, but starting a further 7 engines takes time, even if it's only a few minutes per. With the cartridges, they basically start every engine at the same time.
As for commercial airliners, I don't really know. What research I've done says that you could be started up somewhere between 5-30 minutes. 30 minutes proper, 5 minutes 'The army is coming for you and you need to leave the country ASAP'.
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Kinda dramatic. B-57 cartridge start, both engines simultaneously.
https://youtu.be/gAtZh58JFDU
Boy, when you know what to look for, all kinds of stuff shows up, don't it?
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Kinda dramatic. B-57 cartridge start, both engines simultaneously.
https://youtu.be/gAtZh58JFDU
Boy, when you know what to look for, all kinds of stuff shows up, don't it?
You realize that's from a video game, right ??
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^ No. How do you tell? (I've been fooled before.)
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^ No. How do you tell? (I've been fooled before.)
There's lots and lots and lots of clues with that. I'd start with "everything", but that's not very helpful.
So, to start with stuff I can express:
The color and texture of the pavement, ground, and such.
The buildings in the background are too similar, too flat.
The shadings of the plane, the pixelation, etc...
The way the shadows lay on things
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Well, even full screen, it looks legit to me. The red "US Air Force" and no other insignia is odd, though. Is Strike Fighters 2 a known game? To me, it could be any aero or "ten best" type of site.
ETA
You added some clues after I posted this, but, like, you know, "too flat" and "too that" aren't too definitive. I thought airfields were supposed to be flat.
I guess I'd better start taking a second glance at some of these things. On the other hand, I'm no forensic video analyst.
So thanks.
Did anyone else take it at face value?
Terry
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Sorry, Terry, it's obviously from a video game. If you don't play them much, it can easily fool you.
The smoke plumes from the cartridge starters are one clue. They're identical plumes, exactly identical.
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Yep, the buildings and tower in the background look "fake". The concrete ramp is one solid piece, Concrete is poured in squares (more or less), and after any amount of use, looks "dirty" from fuel and oil leaks and drips. Aircraft (and ramp equipment) Tire marks. There is none of that here. If you look carefully the aircraft wings have pixelated (stepped) edges, not smooth like a real aircraft.
Those were just a few of the clues...
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I kind of thought it was odd that both plumes came out at the same angle, but I figured, you know, wind. and the same waste gate placement for both engines.
I didn't try to analyze each individual puff and boil in their characteristics, though.
As I said, I've been fooled before, so "shame on me."
Looking at it now, of course, it's "Elementary, my dear Watson."
Terry
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It's a pretty decent video game clip man, which is the point of games. No one would be into them if they had shitty, unrealistic graphics ;)
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It's a pretty decent video game clip man, which is the point of games. No one would be into them if they had shitty, unrealistic graphics ;)
Thank you. I feel much better now. :) Really.
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Well, even full screen, it looks legit to me. The red "US Air Force" and no other insignia is odd, though. Is Strike Fighters 2 a known game? To me, it could be any aero or "ten best" type of site.
https://en.wikipedia.org/wiki/Strike_Fighters_2
Yes, it's a known game.
You added some clues after I posted this, but, like, you know, "too flat" and "too that" aren't too definitive. I thought airfields were supposed to be flat.
I'm not a video analyst either, I've just seen lots of computer graphics. Really, saying things like "too flat" is because there's probably some specific term for the effect, I just don't know it and "too flat" is the easier way to tell. If I was an analyst I'd probably be able to express the differences more.
Here's a real picture:
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fwww.aviastar.org%2Fpictures%2Fusa%2Fmartin_b-57.jpg&hash=537a860e2867fa9f2f9b3938629f272126d32fb8)
Note how different sections of the pavement look, well, different. Different shades, different imperfections, etc... The pavement in the video is a constant 2 colors, really, and those 2 colors are pixelated. The bubble screen, now that I look at it, is a constant diffuser, not a variable one like curved glass with the sun hitting it would be. The smoke looks painted in. Same deal with the buildings in the background - not enough detail for the resolution, what details are there are too sharp, the rest is too flat. By 'too flat' I mean that there's not enough variance. It's like somebody supposedly painted a popcorn ceiling with matte paint, but when you look, they painted a flat ceiling with high-gloss paint. You get the exact same shades across a wide area - when if you look at real images, there's a small but constant difference.
Same deal with the plane itself. No tail number, no AF symbol, not enough different colors on it, etc...
No offense intended, but it's really freaking obvious to those of us 'in the know' that it's computer graphics, not a real life video.
As Andiron said, it's pretty good graphics though I've seen much better.
I didn't try to analyze each individual putt and roil in their characteristics, though.
At least for me, I didn't need to. At least for me, there's enough clues that it pretty much slaps me in the face. All the bullet points I listed is me going back and trying to express *HOW* I could tell.
Look at the pavement in the B-52 video I posted. It has an uneven patch and other imperfections. The smoke travels different paths, and even color shifts a bit. The clouds move. Things like that.
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No one would be into them if they had shitty, unrealistic graphics ;)
Ahem, from the mid 1970's to the early 1980's, I, and my buddies, put a lot of quarters into video arcade games that had some pretty shitty and unrealistic graphics...Tempest and Galaga...
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https://youtu.be/5xO3lYa1bEc?t=44s
B-52 cartridge start.
ETA... Make that *multiple* B-52 cartridge starts.
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https://youtu.be/5xO3lYa1bEc?t=44s
B-52 cartridge start.
ETA... Make that *multiple* B-52 cartridge starts.
Looks fake to me.
:rofl: >:D
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One of the things I thought was interesting was as the engines spooled up, you could see just how much air those engines suck in as the smoke was pulled in from quite a ways away.
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I noticed that too.
A "typical" engine pulls in about 100 lb of air a second, according to NASA.
https://www.grc.nasa.gov/www/k-12/airplane/Animation/turbtyp/ettp.html
That's a cube of air of about 11 feet on a side. Per second.
Terry
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https://youtu.be/5xO3lYa1bEc?t=44s
B-52 cartridge start.
ETA... Make that *multiple* B-52 cartridge starts.
That's got to be some of the best CGI I have ever seen! ;) =D
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Re B-52 video:
That's got to be some of the best CGI I have ever seen! ;) =D
:rofl:
Jes' fer grins, I did some rough numbers as to how much "pull" on a jet engine the partial vacuum it's creating in front of it might be if the plane were standing still but spooled up.
Assuming a 6 foot diameter intake and a 1 psi pressure drop in front of it and neglecting everything else, there would be a pull of about 4000 lbs just due to the vacuum (partial pressure, technically) created by the compressor.
Assume a 6' diameter disc with 14.7 psi on one side and 13.7 psi on the other side.
6' = 72" diameter
(72/2)2 X pi = 4072 square inches of engine inlet opening.
Times 1 psi of "suction" (pressure differential) = 4072 lbs of "pull."
A pressure drop of only 1 psi seems kind of light, but it's scalable, that is, a 2 psi drop would yield an 8000 lb pull on the engine.
And neglecting everything else.
Jes' noodling it around.
Some folks do pushups before their coffee in the morning. :D
Terry, 230RN
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Re B-52 video:
:rofl:
Jes' fer grins, I did some rough numbers as to how much "pull" on a jet engine the partial vacuum it's creating in front of it might be if the plane were standing still but spooled up.
Assuming a 6 foot diameter intake and a 1 psi pressure drop in front of it and neglecting everything else, there would be a pull of about 4000 lbs just due to the vacuum (partial pressure, technically) created by the compressor.
Assume a 6' diameter disc with 14.7 psi on one side and 13.7 psi on the other side.
6' = 72" diameter
(72/2)2 X pi = 4072 square inches of engine inlet opening.
Times 1 psi of "suction" (pressure differential) = 4072 lbs of "pull."
A pressure drop of only 1 psi seems kind of light, but it's scalable, that is, a 2 psi drop would yield an 8000 lb pull on the engine.
And neglecting everything else.
Jes' noodling it around.
Some folks do pushups before their coffee in the morning. :D
Terry, 230RN
Hrm. Now you got me thinkin'..... I wonder what fraction of a jet (or turbofan) engine's thrust is due to "blow" (air and exhaust gases being blown out the rear) and how much is due to "suck" (as Terry so nicely calculated for us).
(insert obligatory Spaceballs reference here)
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Yeah, I started to think about those high-bypass engines, and then how thrust is developed in the combustion chambers of the engine. I personally think jet planes are actually just propeller planes, with the "propeller" being just a big-assed many-bladed ducted fan up front. =D :rofl:
Then I started to think about how afterburners and ramjet engines worked thrust-wise and I decided to just have breakfast and let it go. [popcorn]
Rockets? Hey, simple. You've got a hole in one side of a pressurized chamber, and no hole in the other side.
Voila ! Thrust !
https://youtu.be/9-f5zfMH7QI
(CGIed, but effective.)
Just hacking at it, figuring a 1/2" hole with the valve busted off and 2400 psi in the tank, that's about 471.23889803846898576939650749193 lb of thrust for the first instant of the valve breaking off if my arithmetic is correct.
NAP TIME !
Terry, 230RN
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which begs the question. Does a prop push or pull?
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Ahem, from the mid 1970's to the early 1980's, I, and my buddies, put a lot of quarters into video arcade games that had some pretty shitty and unrealistic graphics...Tempest and Galaga...
Unfair comparison, Galaga was awesome and cutting edge then. Now it's just awesome.