The weight should be greatly reduced with the main fuel burnt. I think they would leave the desent speed high to get maximum effect from the aerodynamic speed brakes, needing less fuel for final braking and landing. I think drag goes up logarithmically with speed, maybe Paddy knows better?
Speed of sound is roughly 740 mph (depending on air temp / humidity). Sound of rockets firing immediately follows the shock wave, which suggests to me the boosters are still supersonic when the engines are re-lit…but I might have that wrong.
I think this is correct, they were just above or below Mack 1 when the rockets fired, but I think their terminal velocity would have been much higher without the air brakes, and they would work best in the denser air at low level.
Happy “Scary Tree Thursday”, Wheelizens!
Some good amateur footage of the Falcon Heavy boosters landing -- with sonic booms. Gave me a better sense of how “hot” those things come in.
http://digg.com/video/simultaneous-landing-spacex-sonic-boom
That was great. Thank you.
Hi, Mac!
I’m even more impressed with SpaceX’s technology after seeing that video. (Especially given the Falcon 9’s size.)
I wonder how much kinetic energy those things have right before the landing burn starts.
The weight should be greatly reduced with the main fuel burnt. I think they would leave the desent speed high to get maximum effect from the aerodynamic speed brakes, needing less fuel for final braking and landing. I think drag goes up logarithmically with speed, maybe Paddy knows better?
Speed of sound is roughly 740 mph (depending on air temp / humidity). Sound of rockets firing immediately follows the shock wave, which suggests to me the boosters are still supersonic when the engines are re-lit…but I might have that wrong.
I think this is correct, they were just above or below Mack 1 when the rockets fired, but I think their terminal velocity would have been much higher without the air brakes, and they would work best in the denser air at low level.
Drag is proportional to the square of the velocity (holding everything else constant).
I thought you would know more than I did. Thank you. Always the straight scoop.
Sure Happy It’s Thursday, Gerbil Nation!
Good morning, Fatwa, and Mac!
Great video, Fatwa! Thanks!
Heya, Paddy!
Glad you and Mac enjoyed the video; we’re such geeks ’round here. 😉
Thanks for the clarification re drag.
I didn’t want to do this, but with the above picture, you’ve forced me to.
You want yer drag? I’ve got yer drag right here!
Heh.
That sounds rather Frischian.
Frisian?
Neigh, you varlet!
It’s been a while since I’ve been called a varlet.
*Thinks to self*
“I’ve still got it; yay!”