VTO launch vehicle with RB545 or Sabre type engines

[pmn1]

Is it possible for a VTO launch vehicle to have RB545 (HOTOL) or Sabre (Skylon) type engines? <div class="Discussion_UserSignature"> </div>

 

[j05h]

<i>> Is it possible for a VTO launch vehicle to have RB545 (HOTOL) or Sabre (Skylon) type engines?</i><br /><br />Have either of those engines been tested in any way? IIRC they are both 100% vaporware. The HOTOL has been talked about for 20+ years with nothing done. The best rocket components are ones that exist, followed by ones that are in active development.<br /><br />Air-breathing engines are best used in the atmosphere, so all that extra hardware in the RB545 only gets used for the first minute of launch. It has a very short amount of time to collect and liquify the oxygen it needs for the rest of the flight. The many proposed rocket-based combined cycle (RBCC) engines have serious practical problems as both launch vehicle and point-to-point engines. The biggest issue is that none have been successfully flown. Ramjets have flown, so have a few scramjets. To my knowledge, no RBCC engine has ever been built, let alone flown. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[annodomini2]

<blockquote><font class="small">In reply to:</font><hr /><p>> Is it possible for a VTO launch vehicle to have RB545 (HOTOL) or Sabre (Skylon) type engines? <br /><br />Have either of those engines been tested in any way? IIRC they are both 100% vaporware. The HOTOL has been talked about for 20+ years with nothing done. The best rocket components are ones that exist, followed by ones that are in active development. <br /><br />Air-breathing engines are best used in the atmosphere, so all that extra hardware in the RB545 only gets used for the first minute of launch. It has a very short amount of time to collect and liquify the oxygen it needs for the rest of the flight. The many proposed rocket-based combined cycle (RBCC) engines have serious practical problems as both launch vehicle and point-to-point engines. The biggest issue is that none have been successfully flown. Ramjets have flown, so have a few scramjets. To my knowledge, no RBCC engine has ever been built, let alone flown. <br /><br />Josh <p><hr /></p></p></blockquote><br /><br />RB545 is classified and so if it was flown we will never know until declassified, i've heard they were possibly bench tested and possibly used for ICBM, although I cannot confirm any source.<br /><br />SABRE is still on the drawing board.<br /><br />They are not totally air breathing, they are air breathing within the atmosphere and a normal rocket out of atmosphere (by concept anyway).<br /><br />The idea being that you increase the ISP of the engine through carrying less propellant during take off, as far as I can decifer from the reactionengines website, they are deliberately winged to allow time to gather and process oxygen into the tanks.<br /><br />So if you were to VTO you may have insufficient time to aquire oxygen negating the LACE benefit somewhat. <div class="Discussion_UserSignature"> </div>