Apollo 8 Launch

ugowar Says:

Aug 11, 2009 - Quite right, you gotta love what reduced atmospheric backpressure does to your performance! I also always find it fascinating to watch rockets go up and their exhaust plumes expanding and interacting with each other if there's more than one engine. I was long puzzled by images of Saturn V's aft end being engulfed by flame around 2 minutes into the flight. Fluid dynamics sure are tricky stuff...

bc1969214 Says:

Aug 11, 2009 - I was watching to see when the plume really spreads out but the angles switch so often and many are closeups that it's hard to see when that starts. Very cool around 2:29 how it has two tails almost like a little rocket is following the Saturn V. Do any Saturn V launch videos get to the point where you can see the escape tower jettison? I was also hoping to see footage of Apollo 4 where Walter Cronkite's studio gets shaken big time and he's excited like a kid. Only heard audio for that.

ugowar Says:

Aug 11, 2009 - This isn't a good angle to see the plume and engulfment, see the Apollo 15 tracker footage I posted, it shows it a bit better. I believe the "two-tails" part is a complicated and larger scale (lower atm pressure) version of the "Mach diamonds" you see with supersonic exhaust interacting with the atmosphere. You can see it in Delta II videos after the solids burn out. There are videos showing tower jettison, "In The Shadow Of The Moon" has footage showing interstage and tower jettison nicely.

bc1969214 Says:

Aug 11, 2009 - Thanks for the heads up on the Apollo 15 footage, that's what I was looking for with the plume. I didn't realize the flame actually goes in front of the engines when there isn't atmospheric pressure to blow it back. It cooks the lower part of the S1C, always though it was just the way the angle made it look. That tower jett I don't think my eyes are good enough for. I did see Shadow sometime back. Was the tower jett from an onboard camera or airborne tracker? I'll rent it again soon.

bc1969214 Says:

Aug 11, 2009 - Question on that flame engulfing the lower part. The shuttle SRBs burn about as long as the Saturn V first stage but don't seem to advance up the vehicle. Is that due to propellants used in S1C vs. SRBs? I assume that's part of it since the shuttle main engines also don't pull a Saturn V.

ugowar Says:

Aug 12, 2009 - I actually think it's not high vacuum that makes the exhaust move *forward* but low (but present) atmospheric pressure there behind the supersonic shockwave of the rocket body that makes a lower pressure (lower than surrounding) suction effect there around the aft end. In complete vacuum, the exhaust would just move away from the rocket, not stick close to the body. The "Shadow" footage is an aircraft camera. You don't see the actual jettison in the movie, but slightly after as it falls away.

ugowar Says:

Aug 12, 2009 - It has to do with the configuration of the vehicle and the nozzle arrangement. The effect is prominent if you have two nozzles close so their exhausts collide and move outward at higher pressure. Shuttle SRBs are far apart so this isn't such a strong effect. Look up "STS-51 launch" video by user mianbentley and see how at 1:55 SRB exhaust starts to get sucked up the base of the ET. A similar thing to Saturn V flow dynamics - there's no airflow to keep the exhaust down so it recirculates up.

bc1969214 Says:

Aug 12, 2009 - Oh yeah, I see that on the shuttle as well. In case anyone want to see it: watch?v=vQ7LCK8AE_g

KERNY86 Says:

Aug 13, 2009 - Very nice video! Thx for uploading :)

youvebeenthunderstru Says:

Aug 14, 2009 - Yes, but with all due respect to you, the astrounauts were trained professionals as well.

BeebeCh1972 Says:

Sep 3, 2009 - Very nice sound of the rocket roar considering the 60s through early-70s was when this mighty rocket ran.

ugowar Says:

Sep 4, 2009 - It's very, very likely that's *not* the authentic Apollo 8 launch sound, but a generic overdub so take it for what it's worth.

stegatops Says:

Oct 8, 2009 - Yes...........that gave me a touch of heartburn too, watching the flames lapping underneath the exhaust outlets.............shades of 1986...........yet this didnt seem to bother the Saturn V rocket at all.

an147 Says:

Oct 9, 2009 - I hope man goes to the moon again.

givemetoast Says:

Oct 10, 2009 - Awesome!

llandudnoboy Says:

Oct 11, 2009 - He will but sadly not in one of these monsters where the entire rocket bar the lunar capsule was destroyed during the mission. Where 99% of the rocket was wasted and never reused again would prove far too expensive today. I'm 47 and can just remember some of those 1969-72 launches. Very exciting.

grbosss Says:

Oct 12, 2009 - During our lifetime

artwleb Says:

Oct 17, 2009 - The RP-1 has carbon in the mixture and hence the yellow opaque color that obscures the inner nozzle............alcohol and peroxide are two additional propellants that produce transparent jets.

ugowar Says:

Oct 20, 2009 - All vehicles, especially ones with more than one engine have heat shields around the engines because at altitude the different plumes will collide and recirculate up, heating the engine section. Even nominal shuttle launches experience this, the SRB exhaust recirculates to the base of the ET so that's why it's always charred and burned out at the bottom after you see it separate.

stormrider62033 Says:

Oct 21, 2009 - there planing on ditching the shuttle and going back to a rocket like this for future missions,also unlike the shuttle these rockets were cleared for almost any weather launches

kingspunkbubble Says:

Oct 24, 2009 - The shuttle looks so seventies. Rockets are timeless.

clayzee001 Says:

Oct 26, 2009 - the shuttles first launch was 1981 ( i think i know it was in the 80s)

clayzee001 Says:

Oct 26, 2009 - the new ares rocket test launches tomorro! :D cant wait!

markzzxx Says:

Nov 1, 2009 - um..apollo 12 got struck by lightning..lookup SCE to AUX

l33tpow3rz Says:

Nov 1, 2009 - the BEST Apollo launch video I've seen... A+