Falcon 1 Staging Recontact - Engine Burp

richard schumacher wrote:

Barring some assembly error the odds of success for the 4th
Falcon 1 flight should be pretty good.

That's what everyone said after the first.

And the second too.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Pat Flannery wrote:

Jeff Findley wrote:
On another list Henry Spencer pointed out that, when they developed the
Saturns, Von Braun's team was pretty much the only team on the planet who
had real experience designing large rockets.


No, Korolev had some good sized ones, like the R-7 (built with some
German input), and Chelomei was working on the UR-500 "Proton" super
ICBM of the Saturn 1 class, a entirely home-grown Soviet design.

Henry has always been able to generate a good spin when he wants to,
but this is a bit much even for him.

Von Braun's team's only real experience was in drawing big rockets, not
building them prior to Saturn I. Up till that point the largest thing
they had actually built was Jupiter, which wasn't even a ICBM.
Their multistage experience consisted of clustered solids atop the Juno
1 and 2 boosters, based on the Redstone and Jupiter respectively. I
don't know how much input they had on the V-2/WAC Corporal tests.

Ayup. Not to mention the Titan -II and -III that were getting going
about the same time as the Saturn program was.

If anything, vB and team were held back for years because they
belonged to the Army who worked mostly on smaller missiles/launchers.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

richard schumacher wrote:

:In article ,
: Fred J. McCall wrote:
:
: :Those are methods for cutting the stages apart. Then you need something
: :to ensure that they continue moving away from each other: thrusters on
: :the first stage to slow it, or firing the second stage just before
: :separation.
: :
:
: Or maybe just some strong springs compressed between the stages and
: some pop-out drag brakes on the first stage. Not much air up there,
: but you're already moving pretty fast so maybe just a little drag is
: enough...
:
:A potential problem with single-impulse separation methods such as
:springs arises if the first stage continues to generate thrust, because
:it can then catch up with the second stage. This is exactly what
:happened with the 3rd Falcon 1 flight.
:

That's sort of the point of the drag brakes I mentioned...

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

On Aug 7, 11:59*pm, Fred J. McCall wrote:

That's sort of the point of the drag brakes I mentioned...

They wouldn't work due to low air density. Also would add extra
weight and unnecessary complexity.

The best and easiest solution is to add a delay. Delta-IV is a larger
vehicle and it only has springs. No ullage or retro motors, no drag
flaps, etc

Jeff Findley wrote:
On another discussion forum, Henry Spencer said this is almost exactly what
nearly happened during Apollo 15's S-IC separation, so naturally I went
digging for details.

http://history.nasa.gov/alsj/a15/a15mrp6.pdf

Quote from above:

Four of the eight S-IC retromotors and all of the S-II stage
ullage motors were removed for this flight; therefore, the
S-IC/S-II separation sequence was revised. This sequence change
extended the coast period between S-IC outboard engine cutoff
and S-II engine start command by one second. The S-IC/S-II
separation sequence and S-II engine thrust buildup performance
was satisfactory.

From what I understand, the above deleted motors were added back for
subsequent flights, but I can't find a PDF online to confirm this.


No, they stayed off on all Apollo J-series flights IIRC (15, 16, 17).

Pat

"Pat Flannery" wrote in message
telephone...


Jeff Findley wrote:
On another discussion forum, Henry Spencer said this is almost exactly
what nearly happened during Apollo 15's S-IC separation, so naturally I
went digging for details.

http://history.nasa.gov/alsj/a15/a15mrp6.pdf

Quote from above:

Four of the eight S-IC retromotors and all of the S-II stage
ullage motors were removed for this flight; therefore, the
S-IC/S-II separation sequence was revised. This sequence change
extended the coast period between S-IC outboard engine cutoff
and S-II engine start command by one second. The S-IC/S-II
separation sequence and S-II engine thrust buildup performance
was satisfactory.

From what I understand, the above deleted motors were added back for
subsequent flights, but I can't find a PDF online to confirm this.


No, they stayed off on all Apollo J-series flights IIRC (15, 16, 17).

Actually, the PDF's that Jorge found (see his recent post in this thread)
clearly state that they went back to eight retromotors for the S-1C stage on
Apollo 16 and Apollo 17 (twice the number on Apollo 15).

Perhaps the ullage motors on the S-II stage weren't added back for 16 and
17?

Still, it's clear there was a bit of tweaking going on with the Saturn V to
eek out a bit more performance on later flights. The other point I wanted
to make was that even von Braun's team cut back too far at times, as was the
case with the S-1C retromotors.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

wrote:

:On Aug 7, 11:59*pm, Fred J. McCall wrote:
:
: That's sort of the point of the drag brakes I mentioned...
:
:They wouldn't work due to low air density. Also would add extra
:weight and unnecessary complexity.
:

If that's so, then it seems that a simple accelerometer would work.
Wait until you see acceleration go to zero and then fire separation
devices.

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

Derek Lyons wrote:

Ayup. Not to mention the Titan -II and -III that were getting going
about the same time as the Saturn program was.

If anything, vB and team were held back for years because they
belonged to the Army who worked mostly on smaller missiles/launchers.


In fact, the Atlas was a lot more sophisticated concept than Jupiter,
despite dating from the same time period*.
His Army team also never seemed to realize the advantages of solid or
hypergolic liquid fuels for military missiles, despite the fact that the
Germans were planning to switch to to hypergolics for improved versions
of the V-2, as transporting the LOX around was a pain in the rear due to
evaporation.
Neither Redstone or Jupiter really had the portability of the V-2
either, so in some ways his team was moving backwards in regards to
missile technology from what was done in WW II.

* Convair did have Krafft Ehricke working for them though, and he had
some very advanced ideas in regards to rockets.
Pity we didn't build this thing:
http://website.lineone.net/~geowood/convair2.jpg
http://website.lineone.net/~geowood/convair1.jpg


Pat

Fred J. McCall wrote:
:A potential problem with single-impulse separation methods such as
:springs arises if the first stage continues to generate thrust, because
:it can then catch up with the second stage. This is exactly what
:happened with the 3rd Falcon 1 flight.
:

That's sort of the point of the drag brakes I mentioned...


At that staging altitude they are going to have to be fairly large to
have much effect.

Pat

Pat Flannery wrote:

From what I understand, the above deleted motors were added back for
subsequent flights, but I can't find a PDF online to confirm this.


No, they stayed off on all Apollo J-series flights IIRC (15, 16, 17).

Well, I was half right...they stayed off of the interstage at least. :-[

Pat