[FPSPACE] Soyuz LV question

[Nicolas PILLET]

Dear friends,

Since this discussion is very fruitful, I am going on with a little question concerning the ignition sequence of the Soyuz family launchers.

In the Boris Chertok's book, Volume 2 (page 301 of Asif's English version), it is written :

"First only the strapon boosters would fire. They would be allowed to
build up sustained thrust to an intermediate stage that was less than the weight of
the entire cluster. Here, the destabilizing moment resulting from the thrust variation
at the intermediate stage would be counteracted by the reactions of the launch
system supports. The central sustainer would be permitted to build up to full thrust
after the stable operation of all the strapon booster engines had been electrically
monitored. As the central sustainer engine gained thrust, the missile would begin
to lift off and it would safely separate from the launch system. In flight, the strapon
booster engines would build up to full thrust nominal mode."

Is it still true ? I mean, this was true for the first R-7 launches, but does the present launcher still use this sequence ?
If yes, do you have some detailed chronology of the ignition sequence (which seems a bit complex) ?

According to the acceleration ("peregruzka") scheme availble on this page :
http://www.forum-conquete-spatiale.fr/russie-f9/lancement-soyouz-tma16-30-septembre-t7833-75.htm
there is some event at about T+60s... Do you know what is it ?

Last question : I had some reliable informations which stated that first stage separation occurs at T+118.03s. But on the TsUP website (http://www.mcc.rsa.ru/sojuztma16/start.htm), they write sep occurs at T+117.80s.
Could you clarify this ?

Thank you very much for your precious help !!

Regards,

Nicolas

Date: Mon, 28 Sep 2009 11:54:35 +0200
From: agzak at optonline.net
Subject: Re: [FPSPACE] Soyuz LV question
To: nikolai39 at hotmail.fr; fpspace at friends-partners.org





Re: [FPSPACE] Soyuz LV question


Yes, there is a  valve and, no, there are no attachments to the “tulip”, which opens up by gravity as soon as the thrust of engines is sufficient to lift the rocket and it is no longer presses on the launch structure. To clarify, I published an old Soviet drawing illustrating the process of stage separation here:



http://www.russianspaceweb.com/r7.html



Anatoly  Zak 





On 9/28/09 11:45 AM, "Nicolas PILLET" <nikolai39 at hotmail.fr> wrote:



The picture is here :



http://www.kosmonavtika.com/strap-on.jpg



So I repeat my question : is it the valve which throw LOX after the burn completion ?



Concerning the "tulip" : before liftoff, the launcher is just laying on the arms ? There is no mechanism to attach it ?



> From: kirin at hippo.ru

> To: fpspace at friends-partners.org

> Date: Sun, 28 Sep 2008 00:03:55 -0400

> Subject: Re: [FPSPACE] Soyuz LV question

> 

> On Sunday 27 September 2009 08:54 am, Nicolas PILLET wrote:

> > Thank you very Sergei, this is very clear now !

> Bon soir collegue!

> 

> > It confirms some informations written in Asif Siddiqi's Bible !

> 

> > Two more questions :

> > - at the moment of liftoff, how are separated the four arms ("tiulpann") of

> > the launch complex from the lateral blocks ?

> only by gravitation. When weight of lanceur spatiale become less than thrust 

> the vehicle begin the motion and nothing stop tulip opening.

> 

> 

> > - see the picture I've joined : is it the valve which throw LOX after the

> > burn completion ?

> Je regrete beacoup mai il y a pas de image!

> 

> 

> 

> > Thanks again !

> > Nicolas

> 

> Sincerely yours

> Sergey V. Andreev

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