Re: Re: Multiple engines (was RE: Liquox)

Hans Ulrich Ammann wrote:
> HS> That particular problem can be reduced, for single-axis gimbaling, using
> HS> the technique used for the British peroxide engines:  put the gimbal axis
> HS> at roughly the engine center of mass, rather than up above the engine.
> HS> (The Brits took this one step farther and ran the propellants in along
> HS> the axis, one from each side, so that they could use rotary seals rather
> HS> than flexible hoses.)
> 
> If memory serves there are also Russian examples of single- axis hinged vernier
> engines running on LOX/Kero, where the propellants go through the hinges and
> tightness is achieved by rotary seals.
> A good and inexpensive solution compared to restrained metallic bellows especially
> if it comes to higher pressures.

That were/are the RCS-engines of the Soyus RD-107/108:

http://www.spl.ch/temp/RD-107/RCS_RD-107_1.jpg

http://www.spl.ch/temp/RD-107/RCS_RD-107_2.jpg

1) Combustion Chamber, 2) Fuel Supply Line, 3) Shield, 4)
Movable Fuel Supply Port, 5) Drainage, 6) Oxidizer Pyro-Vale,
7) Pyro-Charge ,8) Oxidizer L, 9) Cable, 10),11) Heat Protection
Layer, 12) Movable Oxidizer Supply Port, 13) Protection
Cover, 14)Throat Plug, 15) Protection Cone (removed before flight)

It can be gimbaled +/- 6°

A cross section of the bearing with the integrated LOX-supply:

http://www.spl.ch/temp/RD-107/RCS_RD-107_3.jpg

1) spigot join, 2),11),20) bearing, 3),16),28),29) ring, 4) screw nut,
5),26) housing, 6) plate (disk), 7) fixation, 9) cover, 10) screw, 12) screw 
for fixation of the split washer, 13),25) split washer, 14) drainage, 15) 
seal, 17) seal ring, 18),19),20),30) plain washer, 21) bushing, 22) supply 
line, 23) bushing with diaphragm, 24) spring for pre-press of the seal
rings, spring for press of the seal (15), 30) dust protection seals

Dito for the Kero:

http://www.spl.ch/temp/RD-107/RCS_RD-107_4.jpg

maybe not that easy to implement :-)

Bruno

-- 
Bruno Berger
Swiss Propulsion Laboratory
E-Mail: [email protected] (HTML-Mails will be dropped!)
WWW:    http://www.spl.ch
HAM:    HB9RSU