I was a Titan II engineer. I noticed a trivial mistake. The start cartridge is like a shotgun shell. It explodes to create the gas that causes the turbine to start spinning. The sound you hear is the turbine spinning up. That starts the APU (using the hypergolic combustion) which pumps the fuel and oxidizer into the combustion chamber. The APU is like a small rocket engine and, if you can find a high quality video or picture, you can see the exhaust from the APU as the rocket rises.
Thats not correct. An explosion is generally defined as a rapid expansion in volume of any kind. If the expansion is supersonic its regarded as a detonation, if its subsonic then its deflagration.
I am 67 years old and grew up watching and closely following each launch, I still retain that interest. I love your videos, and especially like the one explaining the sound that the Gemini-Titan II first stage engine turbo-pumps made. I always loved that sound! Keep up the good work!!
I worked for Aerojet for many years and had the opportunity to sit 700 feet from a Titan first stage at the test stand in Sacramento and when the engine fired we heard a big bang then the engine rumbled to life a few seconds later. It was amazing to experience it in person and in proximity to the engine. I saw many tests over the years there at the Sacto plant and trust me, nothing compares to a big engine or motor firing.
As a historic plane nut, I immediately recognised the cartridge sound from watching Canberra bombers in both the US and UK types start-up. They still use cartridges, but have much smaller and lighter turbines, so they have a much higher noise.
I love your channel! I was a boy of 6 during the Gemini days. In fact, we lived in Houston! I can never look back to my early years without Gemini and Apollo showing very prominently. Sure miss those days! I never was a a sports fan. The Astronauts were my team! To a young boy, they were 9' tall and bullet proof. I can't agree more with you about Pete Conrad. I'll bet he was a real cool guy to hang around with! Never a dull moment around him, eh?
I watched every manned Gemini launch as a kid, and remember hearing that sound several times. I always thought it was the sound of air being pushed through and out of the tower exhaust deflection tunnel (notice the blast exhaust goes to the left side in this video). I've thought this for 50 years and finally found out the correct answer!
I love how the space shuttle sounds when it's main engines fire. At first it's just a mess of a noise but a few seconds in it changes into a consistent more pleasing whooshing sound as the engines stabilize moments before the booster ignition.
That sound is very similar to tractor trucks that use an air motor to start their engines. It sounds almost exactly like the air impact-wrenches you hear at a tire service center.
robyrobyroby12345 I'm not sure it was the same combination but yes, it was hypergols. I think the SPS engine on the CSM was as well. When I'm not in New Horizons mode I'll look into it and maybe do a video on what fuel/oxidizer combinations were used where. Not the sexiest topic but interesting!
robyrobyroby12345 Yes that was the same fuel. It was also used by the Descent Propulsion System of the LM and the Service Propulsion System of the CSM.
Amy, I have two comments. The first one is simple....I am so glad that you make these videos, you are pleasant to listen to, you explain things in a form that non-engineers can follow and you always seem to be having fun. My second comment is a bit irrelevant but here goes...I think you are cute as a doll. As a 50 year old man, having grown up entirely in the "Space Age", the topic can get really dry and technical. You brighten up the topic with a lovely smile, a sweet personality and a very attractive appearance. I can always look forward to your videos and know I will enjoy them on many levels! Keep up the great work!
I was in kindergarten when we watched the launch of Apollo 7 in class here in Houston, Tx. First manned Apollo flight, of course. I doubt if you were around then, but I sure can appreciate your knowledge of our space program history!
Not sure what you mean by 'popping' sounds dude. But the bangs you hear before it lands are sonic booms. The only sounds I could generally hear after shuttle landings were the orbiter's auxiliary power units.
Yeah I always thought they were the APU's. In a night landing you could sometimes see flames coming out of the exhausts underneath the tail. But I'm no expert on the Shuttle. My strength is Apollo.
Starter cartridges have been used in aviation for many years. Watch a typical 50s jet such as a Canberra (or its American version, the Martin B-57) start up and you'll see and hear the cartridges light up. They produce a lot of thick black smoke although in a rocket launch the smoke would be overwhelmed by the much thicker rocket exhaust.
I did knew about cartridges for jet engines startup, but i've never think of them for starting a turbopump and making this funny noise. hahahaha Thank you, for another excellent video, Amy!
Thanks Amy. The Lance missile I worked with in the US Army also used a hypergolic fuel system. We used unsymmetrical dimethyl hydrazine ( UDMH ) as our fuel and inhibited red fuming nitric acid ( IRFNA ) as our oxidizer. We did not make any BWOOP noise when we launched haha. we used something called a SPGG ( pronounced speegee ) , which was a Solid Propellant Gas Generator. After the Safe/Arm switch was thrown and then the Safe/Fire switch ignited the SPGG which created great presure forcing the fuel and oxidizer to meet in the engine. And Boom.....combustion. Actually it was really 2 engines. We had one engine inside another engine. The main engine was the booster engine which burned was more powerful and got the missile off the ground and going mach 3 before it cleared the launcher. Then after the booster cut itself off the sustainer engine at the core of the booster would continue as long as the monitor programmer had programmed it to in order to reach the target. No, we didn't have a BWOOP at launch but she sure did give a mighty ROARRRRRRR.
The Cape engineers called it "the Titan screech." As a kid, watching each launch on black and white TV, this exuberant whoop was unmistakable -- and somehow appropriate for the hypergolic engine start of a big, bruising ICBM designed to carry thermonuclear warheads. My friends and I would try to imitate it. Also interesting was that some of the Gemini launches took place exactly on the hour... meaning the Titan screech would morph into a loud "BEEP" tone from the local TV station at liftoff. Beyond cool, Ms. Amy !
+Amy Shira Teitel (Vintage Space) It's one reason they finally went with solid fuel ICBMs, even hypergolics have to many moving parts that can fail. Still hard to beleive that the nation's deterrent once hinged on the Atlas. "Yes, Mr Soviet President? Can you give us at least half an hour warning before you launch an attack?"
As a kid, I followed many of the launches and missions of NASA, from the early Mercuries to the Apollos. Nostalgic to think how much was accomplished and achieved in such a short time. Great video.
Hi Amy! Do you even upload new Mercury/Gemini/Saturn Apollo videos anymore? Just wondering, cuz you did a great job and will be missed if you've quit. Anyway, I always loved the Gemini's Titan rocketships. Their engines looked and sounded cool, the whole rocket did. But can you or anyone else answer this question for me? What did the red Insignias on the upper porcelain (looking) portions of it's first stage engines stand for? Does anyone know? I tried to find out via Google about who made the engines and it just says Martin. But the Insignia looks like two letters overlapping in red. Just one of those things that's driving me crazy right now. LOL ? 🤔🚀 ?
I served in the US Air Force at Patrick Air Force Base, just south of Cocoa Beach, from November 1963 until mid 1966. I was the driver and aide to the Commander, 6555th Aerospace Test Wing and as such I attended all of the Gemini-Titain launches at Cape Kenndy. I also got to meet most of the astronauts.
Thanks for the videos. I am glad that I found them. I grew up watching all of these space adventures. I did a quick search of your videos and did not see one about how Gordon Cooper lost all of his instruments while in orbit and had only his watch and manual control to bring him down safely. Could you research that flight and do a video?
bit late to the party for this one, but thanks for the video Amy. I've watched a lot of old launch videos over the years and wondered exactly what that obnoxious noise was. I used to have an old beat up chevy that made exactly the same noise when i turned the motor over. thought it was a slipping belt but now i know it was the start cartridge.
You explained it well. I recall hearing that odd sound in several Gemini Titan launch videos and though I was a Titan troop in the military (1980-83), I never got to witness a Titan II launch and here that noise live. I recall the start carts as we used to call them. But I was mainly electronics and guidance (E-lab) and didn't work on propulsion systems.
I always subconsciously noticed that Titan II missile ignition sound, but somehow attributed it to being the result of relatively primitive rocket engine technology. Another great informative video from Amy!
Found this while searching for Hot Staging, but I have wondered what that sound was for decades... just didn't know how to to describe it... I thought it was more of a Fwoop than a Bwoop... but Thank You.
The hum she talks about was the APU turbines that were used to jam fuel and oxidizer into the combustion chamber. I can tell you a little known story about this APU. I was an Electrical Engineer in the Titan II from 69 to 73. Around 73 the AF sent one of our rockets to Vandenberg Air Force Base for a test launch. But the APU's turbo exploded in the silo. What happened was that a train crossed the rocket's trajectory and the commander selected an abort during a critical point in the launch sequence. Now, there are two pre-valves that held the oxidizer and fuel from passing into the turbines of the APU that she is talking about. There are two relays involved with the pre-valves (1) a motor driven relay actually opening the pre-valve and (2) a relay that sends the signal to the launch console saying that the pre-valves were open. The two relays were expected to operate simultaneously. But there is a very short window where they are not because the relay that opened the pre-valves was motor driven and the one that sent the "ok" signal was not. When the abort was given the pre-valves were not opened because the motor driven relay could stop right in its tracks but the relay that sent the signal to say they were open continued to close. When the launch was continued the start cartridge that she is talking about fired and the turbo (without fule/ox) spun up to many-many times it's design speed and exploded.
Just one note, around 1:00 you say "if the tanks are pressurized the sheer force of gravity will actually feed those two fuels". There are a few problems here. Some hypergolic systems (for example, the Apollo Lunar Module Ascent Stage engines, if I'm not mistaken) use pressurized fuel and oxidizer tanks specifically so that no turbo pump is needed. The tanks are pressurized with an inert gas and the pressure of that gas is what pushes the fuel and oxidizer out into the mixing chamber. That's it, no pump and works independently of gravity. Extremely reliable - the only moving parts are the valves and aside from that it's all just pressure and chemistry. Very robust. As to gravity-fed, you could conceivably get away with using a gravity-fed system to kickstart a turbo pump with no separate starter charge and no tank pressurization, though I don't know if that's actually used in any system (would be a bit how-ya-doin). Aside from that, all sounds right to me. Nicely done.
I was a kid living on Cocoa Beach next toe Cape Canaveral during the Mercury-Redstone and Mercury-Atlas missions, but we moved away before the Gemini-Titan missions. But my father was present at at least a couple early Titan launches (not sure if they were civilian launches at the Cape, or Air Force lanuches of the ICBM version of the Titan) and he used to recall to me that the "bwoop" always made in impression on him. Very distinctive to the Titan. I have a pretty good collection of videos showing Titan launches, and most have the "bwoop" but usually not too clearly recorded. I KNOW that somewhere I have a video that make the "bwoop" clearly audible. I visited the Titan Missile Museum in Arizona, and was surprised that they were not happy with their own collection of sounds from Titan launches because they though the "bwoop" was not easy enough to hear. I painstakingly went through my entire video collection, but could not find that one video with the really good "bwoop", so I was not able top help them out. Still one of my favorite sounds, along with the B-36 engines, etc.
It wasn't the start cartridge but mainly the turbo pumps winding up to speed which made the noise. I heard plenty of them on Titan IIIB launches at Vandenberg. In real life it sounded like a jet engine starting up super fast. BTW the start cartridge was like a small solid fuel rocket.
Great explanation! I've watched nearly every watch video from Mercury through Apollo (several times) and never noticed this sound on Gemini. And now, thanks to this video, I can't help but notice it. Thank you for unclogging my ears, lol.
I am an hydroelectric engeneer and an enormous fan of rockets. And thusly, for a men like me, that whistle is as satisfying as mindblowing, if I think at the crazy revs these Gemini-Titan turbines were used to spin before the ignition in order to produce such a noise!! ❤💪🏻✨️
The start cart "bwoop" was not due to the combustion, the sound itself was the gear-train spooling up the Roots-type impellers of the rocket engine pumps and auxiluary burner (that continued the engine pump pressure for the burn) to operational pressures and burn.
The RD-180/181 makes the blooping sound too, just with a much lower pitch. (Both of them are derived from RD-170, which is used on the Energiya launcher designed to launch Buran, the Soviet version of the Space Shuttle)
@Vintage Space - 2 questions about Apollo missions. 1 - How did the crew access the equipment stored in the Service Module? (The reentry shield prevented the astronauts from directly - THRU the shield. ) 2 - Where was the Lunar Module stored (in the Commands Module?) and how was access to it attained?
It's probably worth mentioning that we don't see that kind of system on most rockets because the Titan Gemini was derived from a liquid-fueled ICBM that needed to be able to start up very quickly and reliably with minimal prep time, whereas purpose-built launch systems have plenty of time to ready non-shelf-stable ignition systems. I would bet the start cartridge system is almost identical to the one used to kick-start the engines of a B-52 for scramble.
have you done/will you do a show on the F-1 engine from the saturn V. Some of the engineering stories from its development are astounding, especiall when you consider that they had essentially no computer modelling to help them figure it out...
The F-1 engines on the Saturn V used propellant cartridges to start the turbopumps, then after that the combustion cycle of LOX and RP1 kept her running. You don't hear them kick over like the Titan-II's, for all Hell is breaking loose with the F-1s firing. You can hear a dramatized startup in the movie APOLLO 13 during launch, it sounds like water hammer. The nice thing about the F-1s is that they are self-dampening. Meaning, if an combustion instability event happens, they actually self-dampen and stabilize themselves, even with external events (eg, test explosive devices going off inside the engine bell).
I was a Titan II engineer. I noticed a trivial mistake. The start cartridge is like a shotgun shell. It explodes to create the gas that causes the turbine to start spinning. The sound you hear is the turbine spinning up. That starts the APU (using the hypergolic combustion) which pumps the fuel and oxidizer into the combustion chamber. The APU is like a small rocket engine and, if you can find a high quality video or picture, you can see the exhaust from the APU as the rocket rises.
Actually, it deflagrates (burns); it does not explode (which is detonation).
Thats not correct. An explosion is generally defined as a rapid expansion in volume of any kind.
If the expansion is supersonic its regarded as a detonation,
if its subsonic then its deflagration.
That makes sense, it sounded more like a mechanical cranking, i.e. the turbine starting, than an electronic "bloop".
Geez how old are you
I like Amy's explanation better even though yours might be correct. She looks so cute making the rocket noise.
The Titan II "bwoop" is one of my favorite sounds ever.
We need a Titan II bwoop compilation
Me too
It is the Titan's way of saying "It's showtime!"
@@navelriver 🤘
Because that is the sound a happy rocket makes! :)
Or a turbo on a internal combustion engine
*"BWOOP, LET'S GO!"*
Happy rocket!!!! I actually giggled when I read this!!
I don't know how you pull it off; rapid, informative, straight to the point and still entertaining! Well done, thanks!
I am 67 years old and grew up watching and closely following each launch, I still retain that interest. I love your videos, and especially like the one explaining the sound that the Gemini-Titan II first stage engine turbo-pumps made. I always loved that sound! Keep up the good work!!
At my age, I sound like that when I wake up too.
lol!
Lol! It does sound like a kid whining about something they don't want to do.
I had forgot all about that noise. When you made the noise I snickered, but as soon as you showed the clip I remembered. Thank you for the memories.
Love your videos, Amy. I am 62, and remember all of this, but it never ceases to amaze me what more I learn from watching your work. Awesome.
I worked for Aerojet for many years and had the opportunity to sit 700 feet from a Titan first stage at the test stand in Sacramento and when the engine fired we heard a big bang then the engine rumbled to life a few seconds later. It was amazing to experience it in person and in proximity to the engine. I saw many tests over the years there at the Sacto plant and trust me, nothing compares to a big engine or motor firing.
As a historic plane nut, I immediately recognised the cartridge sound from watching Canberra bombers in both the US and UK types start-up. They still use cartridges, but have much smaller and lighter turbines, so they have a much higher noise.
I love your channel! I was a boy of 6 during the Gemini days. In fact, we lived in Houston! I can never look back to my early years without Gemini and Apollo showing very prominently. Sure miss those days! I never was a a sports fan. The Astronauts were my team! To a young boy, they were 9' tall and bullet proof.
I can't agree more with you about Pete Conrad. I'll bet he was a real cool guy to hang around with!
Never a dull moment around him, eh?
I watched every manned Gemini launch as a kid, and remember hearing that sound several times. I always thought it was the sound of air being pushed through and out of the tower exhaust deflection tunnel (notice the blast exhaust goes to the left side in this video). I've thought this for 50 years and finally found out the correct answer!
You should definitely demonstrate that sound a few more times!
Love that sound. Also the LR-87 was one of the coolest engines of it's time. Could run on three different fuels with modification.
I love how the space shuttle sounds when it's main engines fire. At first it's just a mess of a noise but a few seconds in it changes into a consistent more pleasing whooshing sound as the engines stabilize moments before the booster ignition.
That sound is very similar to tractor trucks that use an air motor to start their engines. It sounds almost exactly like the air impact-wrenches you hear at a tire service center.
+Edward Cabaniss Right you are! That sound is the venting of the drive gases.
Was that the same fuel/oxidizer combo as the LM ascent stages?
Your "bwoop" impression was spot on, of course.
robyrobyroby12345 I'm not sure it was the same combination but yes, it was hypergols. I think the SPS engine on the CSM was as well. When I'm not in New Horizons mode I'll look into it and maybe do a video on what fuel/oxidizer combinations were used where. Not the sexiest topic but interesting!
robyrobyroby12345 Yes that was the same fuel. It was also used by the Descent Propulsion System of the LM and the Service Propulsion System of the CSM.
Love your 'bwoop' impression, AST, but on most videos it sounds to me more like a skidding automobile just before the crash!
It was said it be, but the Apollo 17 ascent module left no flame or smoke. Riddle me that?
@@marynollaig4124
It was operating in a vacuum.
And I thought that noise was a rope starter all these years...
lol!
NipkowDisk Titan II for sale, lightly used. Cash only, fully vaccinated. Starts first pull every time.
Derek Pierce SOLD lol
LOL imagine being that guy.
LMAO!
The start cartridge sort of reminds me of the Coffman starters that were used to start large piston driven aircraft engines.
Didn't they use Kaufman starter in the film " Flight of the Phoenix. "?
Are they like a big shotgun shell?
Yup, they're Coffman starters though, OP is right on this one
Fastest way to get the engine spinnin' :D
I recently read that there were also smaller versions of the shells used to start up diesel engines in tractors such as the Field Marshall.
That's exactly what it is! It's a gas cartridge,fired to initially spin up the fuel pump turbine.
Amy, I have two comments. The first one is simple....I am so glad that you make these videos, you are pleasant to listen to, you explain things in a form that non-engineers can follow and you always seem to be having fun. My second comment is a bit irrelevant but here goes...I think you are cute as a doll. As a 50 year old man, having grown up entirely in the "Space Age", the topic can get really dry and technical. You brighten up the topic with a lovely smile, a sweet personality and a very attractive appearance. I can always look forward to your videos and know I will enjoy them on many levels! Keep up the great work!
I grew up during those space days! Never missed a launch on TV or a splashdown! So much fun!
I was in kindergarten when we watched the launch of Apollo 7 in class here in Houston, Tx. First manned Apollo flight, of course. I doubt if you were around then, but I sure can appreciate your knowledge of our space program history!
Bwoop! I think that was pretty good! Do you do any other impressions? Lol! Great video Amy!
mvglackin Just a lot of impressions of my cat chirping. He's a good little chirper!
You did nail it! Can't wait till you do the the sound of Gemini 6A shutting down too! You'll have to put the two together.
Not sure what you mean by 'popping' sounds dude. But the bangs you hear before it lands are sonic booms. The only sounds I could generally hear after shuttle landings were the orbiter's auxiliary power units.
Yeah I always thought they were the APU's. In a night landing you could sometimes see flames coming out of the exhausts underneath the tail. But I'm no expert on the Shuttle. My strength is Apollo.
It scared the crap out of me first time I saw it during a night landing because I thought the orbiter was on fire. But it's normal.
Please say "Bwwooopp" again!
Starter cartridges have been used in aviation for many years. Watch a typical 50s jet such as a Canberra (or its American version, the Martin B-57) start up and you'll see and hear the cartridges light up. They produce a lot of thick black smoke although in a rocket launch the smoke would be overwhelmed by the much thicker rocket exhaust.
Nice sound effects! Very nice job explaining how hypergolic fueled rockets work.
All those years ago watching Gemini launches and never asked why the noise. Thanks, Amy!
I did knew about cartridges for jet engines startup, but i've never think of them for starting a turbopump and making this funny noise. hahahaha
Thank you, for another excellent video, Amy!
ALWAYS happy to be enlightened by Amy Shira Teitel !
You did a great job explaining the starting sequence on the Titan 2. Thanks!
For like two and a half years my text notification sound was your “bwooooop!” noise. 😆
1:44 Bwoop....best sound ever. I need a t shirt made that just says Bwoop on it. Favorite episode of Vintage Space.
You explained it superbly !
Thanks Amy. The Lance missile I worked with in the US Army also used a hypergolic fuel system.
We used unsymmetrical dimethyl hydrazine ( UDMH ) as our fuel and inhibited red fuming nitric acid ( IRFNA )
as our oxidizer.
We did not make any BWOOP noise when we launched haha.
we used something called a SPGG ( pronounced speegee ) , which was a Solid Propellant Gas Generator.
After the Safe/Arm switch was thrown and then the Safe/Fire switch ignited the SPGG which created great presure
forcing the fuel and oxidizer to meet in the engine. And Boom.....combustion.
Actually it was really 2 engines. We had one engine inside another engine.
The main engine was the booster engine which burned was more powerful and got the missile off the ground and going mach 3
before it cleared the launcher. Then after the booster cut itself off the sustainer engine at the core of the booster would continue as long as the monitor programmer had programmed it to in order to reach the target.
No, we didn't have a BWOOP at launch but she sure did give a mighty ROARRRRRRR.
Love the giggle after describing and making the "bwoop" sound.
"I'm not a rocket scientist, but I talk about it on RUclips." That reminds me of an old pain reliever ad. :) BTW, excellent sound effect. :D
The Cape engineers called it "the Titan screech." As a kid, watching each launch on black and white TV, this exuberant whoop was unmistakable -- and somehow appropriate for the hypergolic engine start of a big, bruising ICBM designed to carry thermonuclear warheads. My friends and I would try to imitate it. Also interesting was that some of the Gemini launches took place exactly on the hour... meaning the Titan screech would morph into a loud "BEEP" tone from the local TV station at liftoff. Beyond cool, Ms. Amy !
+Russell S I love "the Titan screech!" I wonder what it would have sounded like in a missile silo... Hmm.
+Amy Shira Teitel (Vintage Space) It's one reason they finally went with solid fuel ICBMs, even hypergolics have to many moving parts that can fail. Still hard to beleive that the nation's deterrent once hinged on the Atlas. "Yes, Mr Soviet President? Can you give us at least half an hour warning before you launch an attack?"
+Amy Shira Teitel (Vintage Space) The sound of imminent total annihilation. The Whoop of Death, if you will.
As a kid, I followed many of the launches and missions of NASA, from the early Mercuries to the Apollos. Nostalgic to think how much was accomplished and achieved in such a short time. Great video.
This is the kind of spaceflight trivia I love to learn about!
Nope, you did a wonderful bwoop! I had never heard it before until you did one yourself. Now I'm going to listen for it every time.
A question I never even thought to ask, thank you and thumbs up on the video.
Great to know what that sound was. I remember hearing that when I watched the Gemini-Titan launches as a kid. A great memory!
My new favorite YT channel!!!!!
Hi Amy! Do you even upload new Mercury/Gemini/Saturn Apollo videos anymore? Just wondering, cuz you did a great job and will be missed if you've quit. Anyway, I always loved the Gemini's Titan rocketships. Their engines looked and sounded cool, the whole rocket did. But can you or anyone else answer this question for me? What did the red Insignias on the upper porcelain (looking) portions of it's first stage engines stand for? Does anyone know? I tried to find out via Google about who made the engines and it just says Martin. But the Insignia looks like two letters overlapping in red. Just one of those things that's driving me crazy right now. LOL
? 🤔🚀 ?
I served in the US Air Force at Patrick Air Force Base, just south of Cocoa Beach, from November 1963 until mid 1966. I was the driver and aide to the Commander, 6555th Aerospace Test Wing and as such I attended all of the Gemini-Titain launches at Cape Kenndy. I also got to meet most of the astronauts.
Thanks for the videos. I am glad that I found them. I grew up watching all of these space adventures. I did a quick search of your videos and did not see one about how Gordon Cooper lost all of his instruments while in orbit and had only his watch and manual control to bring him down safely. Could you research that flight and do a video?
You did fine. I already knew about the reason for the sound and your explanation was excellent. An onboard start cart.
bit late to the party for this one, but thanks for the video Amy.
I've watched a lot of old launch videos over the years and wondered exactly what that obnoxious noise was.
I used to have an old beat up chevy that made exactly the same noise when i turned the motor over. thought it was a slipping belt but now i know it was the start cartridge.
Some aircraft used starter cartridges to get their engine running when conventional starting equipment wasn't available.
Say my name...
You explained it well. I recall hearing that odd sound in several Gemini Titan launch videos and though I was a Titan troop in the military (1980-83), I never got to witness a Titan II launch and here that noise live. I recall the start carts as we used to call them. But I was mainly electronics and guidance (E-lab) and didn't work on propulsion systems.
Bwooop there it is!
I thought you explained it very well and very precisely. Made perfect sense to me and I am FAR from a rocket scientist. Well done Amy!
I always subconsciously noticed that Titan II missile ignition sound, but somehow attributed it to being the result of relatively primitive rocket engine technology. Another great informative video from Amy!
Although this was very interesting, the best part of the video is your facial expression after imitating the sound.
That was an excellent impression!
I've always wondered what that sound was! Thanks for telling us!
Great channel!!! So cool to find another vintage space geek like myself.
Perfectly explained, and now I can't miss it!
I love your videos. Great job explaining this. Hope you start posting more videos soon.
I always just figured they turned the key while the engine was already running. My Buick makes that sound when I do it.
Great stuff: not enough info around on this fascinating subject or the brilliant people involved except for some Appollo and shuttle. Keep it up.
Found this while searching for Hot Staging, but I have wondered what that sound was for decades... just didn't know how to to describe it... I thought it was more of a Fwoop than a Bwoop... but Thank You.
The hum she talks about was the APU turbines that were used to jam fuel and oxidizer into the combustion chamber. I can tell you a little known story about this APU. I was an Electrical Engineer in the Titan II from 69 to 73. Around 73 the AF sent one of our rockets to Vandenberg Air Force Base for a test launch. But the APU's turbo exploded in the silo. What happened was that a train crossed the rocket's trajectory and the commander selected an abort during a critical point in the launch sequence. Now, there are two pre-valves that held the oxidizer and fuel from passing into the turbines of the APU that she is talking about. There are two relays involved with the pre-valves (1) a motor driven relay actually opening the pre-valve and (2) a relay that sends the signal to the launch console saying that the pre-valves were open. The two relays were expected to operate simultaneously. But there is a very short window where they are not because the relay that opened the pre-valves was motor driven and the one that sent the "ok" signal was not. When the abort was given the pre-valves were not opened because the motor driven relay could stop right in its tracks but the relay that sent the signal to say they were open continued to close. When the launch was continued the start cartridge that she is talking about fired and the turbo (without fule/ox) spun up to many-many times it's design speed and exploded.
Very clear. I have wondered about that since I was a child. Thank you.
Just one note, around 1:00 you say "if the tanks are pressurized the sheer force of gravity will actually feed those two fuels". There are a few problems here. Some hypergolic systems (for example, the Apollo Lunar Module Ascent Stage engines, if I'm not mistaken) use pressurized fuel and oxidizer tanks specifically so that no turbo pump is needed. The tanks are pressurized with an inert gas and the pressure of that gas is what pushes the fuel and oxidizer out into the mixing chamber. That's it, no pump and works independently of gravity. Extremely reliable - the only moving parts are the valves and aside from that it's all just pressure and chemistry. Very robust.
As to gravity-fed, you could conceivably get away with using a gravity-fed system to kickstart a turbo pump with no separate starter charge and no tank pressurization, though I don't know if that's actually used in any system (would be a bit how-ya-doin).
Aside from that, all sounds right to me. Nicely done.
I was a kid living on Cocoa Beach next toe Cape Canaveral during the Mercury-Redstone and Mercury-Atlas missions, but we moved away before the Gemini-Titan missions. But my father was present at at least a couple early Titan launches (not sure if they were civilian launches at the Cape, or Air Force lanuches of the ICBM version of the Titan) and he used to recall to me that the "bwoop" always made in impression on him. Very distinctive to the Titan.
I have a pretty good collection of videos showing Titan launches, and most have the "bwoop" but usually not too clearly recorded. I KNOW that somewhere I have a video that make the "bwoop" clearly audible. I visited the Titan Missile Museum in Arizona, and was surprised that they were not happy with their own collection of sounds from Titan launches because they though the "bwoop" was not easy enough to hear. I painstakingly went through my entire video collection, but could not find that one video with the really good "bwoop", so I was not able top help them out.
Still one of my favorite sounds, along with the B-36 engines, etc.
Your a natural at this girl!
Now that you mention it, it makes perfect sense. The sound is almost identical to that made by a diesel engine equipped with compressed-air start.
Memories! so many memories. Titan 1 & 2 Engine specialist 1962-1968
This is one I have actually wondered about. Thank you!
It wasn't the start cartridge but mainly the turbo pumps winding up to speed which made the noise. I heard plenty of them on Titan IIIB launches at Vandenberg. In real life it sounded like a jet engine starting up super fast. BTW the start cartridge was like a small solid fuel rocket.
Great explanation! I've watched nearly every watch video from Mercury through Apollo (several times) and never noticed this sound on Gemini. And now, thanks to this video, I can't help but notice it. Thank you for unclogging my ears, lol.
Amy just showed she has yet another potential career as a sound effects voice artist! A very talented lady indeed.
Love how the ignition on a Titan is instantaneous. There's a much longer delay on non-hypergolic fueled engine startups
I love all your videos. I always learn something new.
Good job explaining!
I DID NOT even know that THERE WAS a "BWOOP"...
Thanks for posting this, Amy!
Ok first of all that's one of the coolest rocket sounds I've ever heard. Sounds like a Star Wars turbolaser.
Secondly, thanks.
I like your "Glen" shirt in this video. John called me at my home when he was a Senator. It was nice hearing from him.
I am an hydroelectric engeneer and an enormous fan of rockets. And thusly, for a men like me, that whistle is as satisfying as mindblowing, if I think at the crazy revs these Gemini-Titan turbines were used to spin before the ignition in order to produce such a noise!! ❤💪🏻✨️
The start cart "bwoop" was not due to the combustion, the sound itself was the gear-train spooling up the Roots-type impellers of the rocket engine pumps and auxiluary burner (that continued the engine pump pressure for the burn) to operational pressures and burn.
With some background in aerospace & physics, I say darn good explanation in 2.5 minutes! Keep 'em coming…balls 8!
The RD-180/181 makes the blooping sound too, just with a much lower pitch.
(Both of them are derived from RD-170, which is used on the Energiya launcher designed to launch Buran, the Soviet version of the Space Shuttle)
@Vintage Space - 2 questions about Apollo missions.
1 - How did the crew access the equipment stored in the Service Module? (The reentry shield prevented the astronauts from directly - THRU the shield. )
2 - Where was the Lunar Module stored (in the Commands Module?) and how was access to it attained?
0:30 “Fluids” is correct. Anything that flows is a “fluid”. That includes liquids and gases.
Nice job Amy!
Your videos are excellent!
That bwoooop sound is up there with the Thermite rail track welding sound in my top sound list.
You have an excellent "ear"! Perfectly done Amy. Have you ever considered yet another career in "overvoicing" SFX?
Thank You for this video presentation. I did not know what caused that sound. It made a cool sound ! Thank you again.
It's probably worth mentioning that we don't see that kind of system on most rockets because the Titan Gemini was derived from a liquid-fueled ICBM that needed to be able to start up very quickly and reliably with minimal prep time, whereas purpose-built launch systems have plenty of time to ready non-shelf-stable ignition systems.
I would bet the start cartridge system is almost identical to the one used to kick-start the engines of a B-52 for scramble.
I honestly had never heard the sound before, very interesting.
As i noticed, it's also happens in Atlas V launches (especially without booster ones so you can hear it clearly)
also delta
have you done/will you do a show on the F-1 engine from the saturn V. Some of the engineering stories from its development are astounding, especiall when you consider that they had essentially no computer modelling to help them figure it out...
just found about your channel. Love what your doing ! Thx!
Great explanation.
The F-1 engines on the Saturn V used propellant cartridges to start the turbopumps, then after that the combustion cycle of LOX and RP1 kept her running. You don't hear them kick over like the Titan-II's, for all Hell is breaking loose with the F-1s firing. You can hear a dramatized startup in the movie APOLLO 13 during launch, it sounds like water hammer.
The nice thing about the F-1s is that they are self-dampening. Meaning, if an combustion instability event happens, they actually self-dampen and stabilize themselves, even with external events (eg, test explosive devices going off inside the engine bell).
Love the Glen Coco tank!
Was Gemini named such for the two pilots or the two engines? A little of both?
My father pointed this out to me as a kid - It's like the cow bell in Don't Fear The Reaper - You will never unhear it once you hear it.
Great explanation. Thanks.