Detailed update on Falcon Heavy static fire test set for later today
Link here. The article has a lot of good information not only about the test but about the launchpad and how it will be used in the future.
One take-away that I came off with however came from the picture of the Falcon Heavy on the launchpad. It made me realize how far apart the two side stages sit from the core stages, as the rocket is now reconfigured. My impression of most strap-ons today is that they are placed very close to the core, and they generally have aerodynamic cones that slope away from the core, so that the air is directed away from the space between the stages. Falcon Heavy however has all that space, and the side strap-ons have rounded cones.
I wonder if this is one of the rocket’s most worrisome unknowns, as it travels through Max Q, the period shortly after launch when the stresses created from its speed and the atmosphere are the highest. As designed, a lot of atmosphere will travel between the stages. While this isn’t entirely unique (the shuttle had a somewhat comparable gaps between its various parts), I do wonder.
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Link here. The article has a lot of good information not only about the test but about the launchpad and how it will be used in the future.
One take-away that I came off with however came from the picture of the Falcon Heavy on the launchpad. It made me realize how far apart the two side stages sit from the core stages, as the rocket is now reconfigured. My impression of most strap-ons today is that they are placed very close to the core, and they generally have aerodynamic cones that slope away from the core, so that the air is directed away from the space between the stages. Falcon Heavy however has all that space, and the side strap-ons have rounded cones.
I wonder if this is one of the rocket’s most worrisome unknowns, as it travels through Max Q, the period shortly after launch when the stresses created from its speed and the atmosphere are the highest. As designed, a lot of atmosphere will travel between the stages. While this isn’t entirely unique (the shuttle had a somewhat comparable gaps between its various parts), I do wonder.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
The aerodynamic issues are certainly a concern, I believe it was one of the things Elon Musk mentioned in that interview where he talked about complex Falcon Heavy turned out to be and how risky this first launch really is. On the other hand, comparing to Delta IV Heavy, the gap and shapes are very similar.
Static fire today in doubt (dated today – 1/16/2017).
https://spaceflightnow.com/2018/01/09/falcon-heavy-demo-flight-preparations/
The gaps between the side cores and the center core look to be roughly a foot wide. I’m not sure this constitutes an aerodynamic problem, especially beyond Mach 1. Long ago, I heard the late Jerry Pournelle tell a story about how Boeing lost the B-70 contract to North American back in the 60’s. Seems Boeing spent a lot of money inventing fabrication processes that would result in a super-smooth outer mold line for their prototype. North American had discovered, via its supersonic fighter and X-15 programs, that the laminar flow boundary layer moved out from an aircraft’s surface quite markedly at supersonic Mach numbers. The North American B-70 was not ultra-smooth all over and was, thus, a lot cheaper to build. This would suggest that the boundary layers of the side cores and the center core of FH will meet along their loci of closest approach pretty early in flight and will obviate any supersonic shock stresses between the cores.