Quote from: wannamoonbase on 12/29/2017 02:09 pmI think the probability of success is pretty high, but not as high as a F9 of course.I think 50-50 is about right. That's what Elon suggested, if I recall correctly. There are certainly some untested aspects of this vehicle, especially base heating, max-q transonic aerodynamic stresses, pogo, etc. History is a guide. The first Delta 4 Heavy failed, as did three of the first six Titan IIIC missions and one of the first two Saturn 5 launches, though only one of those five combined failures was an outright Fail to Orbit.As Elon said, we'll all be happy if this thing gets off the pad and over the Atlantic without mishap. I believe that the odds of at least that happening are pretty good. - Ed Kyle
I think the probability of success is pretty high, but not as high as a F9 of course.
If you watch the the liftoff of the first Falcon 9, it clearly rotates. For a single stick, that's not really a big deal. But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.
Due to thrust torque (a thrust-induced rotation)...I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.
I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.
Due to thrust torque (a thrust-induced rotation)...I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.
So, how close is this beast to the "final" FH?
Quote from: edkyle99 on 12/29/2017 04:05 pmQuote from: wannamoonbase on 12/29/2017 02:09 pmI think the probability of success is pretty high, but not as high as a F9 of course.I think 50-50 is about right. That's what Elon suggested, if I recall correctly. There are certainly some untested aspects of this vehicle, especially base heating, max-q transonic aerodynamic stresses, pogo, etc. History is a guide. The first Delta 4 Heavy failed, as did three of the first six Titan IIIC missions and one of the first two Saturn 5 launches, though only one of those five combined failures was an outright Fail to Orbit.As Elon said, we'll all be happy if this thing gets off the pad and over the Atlantic without mishap. I believe that the odds of at least that happening are pretty good. - Ed KyleI'm amazed that people continue to not understand the expectations game that Elon plays - all the time.If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.
Quote from: mme on 12/29/2017 04:15 pmIf you watch the the liftoff of the first Falcon 9, it clearly rotates. For a single stick, that's not really a big deal. But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.I'm sure that would be a problem if SpaceX was trying to launch three of the very first Falcon 9 1.0 rockets together... given that none of the 45 subsequent Falcon 9's have done this, I'd have to think it isn't a factor today.
I'm amazed that people continue to not understand the expectations game that Elon plays - all the time.If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.
Things can happen but I don’t think there are many unknowns and that SpaceX will be conservative on this first one, as much as they can be anyway.
I have a question that I don't think I've seen addressed yet: Has a 2nd Falcon Heavy core been produced at this point? As we know the FH core is considerably different from the standard F9, and I'm assuming they take longer to build than a standard core. I haven't seen a mention of the status of a second core at this point in time.
Perhaps it's time we had a poll.Example:1. Flight complete success, with all 3 first stages landing intact.2. Makes it past first stage separation and lands at least 2 first stages.3. Makes it past max Q.4. Does not make max Q.