Rocket Powered Blimps?

[BrianSlee]

<p>I am working on a concept that I think has merit.&nbsp; It attempts to insert LTA systems into the launch cycle for orbital insertion.&nbsp; a brief white paper is available at the following URL:&nbsp;&nbsp; http://www.escape-velocity.biz/LTA_Orbital_Launch_Systems.html</p><p>&nbsp;all feedback is welcomed.</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[drwayne]

<p>You probably want to take the time, when joining a new forum, to get the lay of the land before posting.&nbsp; This is particularly true when posting something that is basically an ad for something, in this case an idea.&nbsp; When you just post something in a section that "sort of looks right", then if comes across as a "hit and run, just want to get my link out there, spammish" sort of thing.&nbsp; Actually, having your *very first* post be a link to someplace else gives it that spammish feel.</p><p>This forum has a user announcements section, which is where something like this should go.</p><p>Wayne</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You probably want to take the time, when joining a new forum, to get the lay of the land before posting.&nbsp; This is particularly true when posting something that is basically an ad for something, in this case an idea.&nbsp; When you just post something in a section that "sort of looks right", then if comes across as a "hit and run, just want to get my link out there, spammish" sort of thing.&nbsp; Actually, having your *very first* post be a link to someplace else gives it that spammish feel.This forum has a user announcements section, which is where something like this should go.Wayne&nbsp; <br />Posted by drwayne</DIV><br /><br />Apologies and point taken <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[qso1]

It might be a good idea to identify the components in your graphics so people have a better idea of what they are looking at. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I am working on a concept that I think has merit.&nbsp; It attempts to insert LTA systems into the launch cycle for orbital insertion.&nbsp; a brief white paper is available at the following URL:&nbsp;&nbsp; http://www.escape-velocity.biz/LTA_Orbital_Launch_Systems.htmlall feedback is welcomed. <br />Posted by BrianSlee</DIV></p><p>This ought to be real interesting -- a mach 20 blimp.&nbsp; Any idea what the drag forces look like ?<br /></p> <div class="Discussion_UserSignature"> </div>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>This ought to be real interesting -- a mach 20 blimp.&nbsp; Any idea what the drag forces look like ? <br />Posted by DrRocket</DIV><br /><br />very altitude dependent.&nbsp; Speed is obviously limited in the atmosphere.&nbsp; Form drag is still a first order effect even at an altitude of 100KM.&nbsp; <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p>The idea of lifting the rocket to 30KM altitude with a balloon certainly sounds like something that might reduce launch costs. The balloon should perhaps act as the first stage, that would be discarded altogether, after the required altitude has been reached and the 2nd stage is fired.</p><p>What kind of masses could the blimp or balloon expect to be able to lift to 30KM, where the air pressure is only some 1 - 2% of that of the ground level?&nbsp;</p>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The idea of lifting the rocket to 30KM altitude with a balloon certainly sounds like something that might reduce launch costs. The balloon should perhaps act as the first stage, that would be discarded altogether, after the required altitude has been reached and the 2nd stage is fired.What kind of masses could the blimp or balloon expect to be able to lift to 30KM, where the air pressure is only some 1 - 2% of that of the ground level?&nbsp; <br />Posted by aphh</DIV></p><p>&nbsp;If the system is used as a primary lifter Neutral buyancy should be attained at app 20,000 ft.&nbsp; Using brute power and aerodynamic lift from that point I believe for a rocket powered version using SSMEs it would carry 500 tons to just under 30 KM at a speed of 500 knots</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p>Did I get this right; for orbital operation the first stage would use hydrogen as the LTA component providing lift to certain altitude. 2nd stage would then use the same hydrogen as rocket fuel to propel the vehicle to certain speed. The 3rd stage would be conventional upper stage?</p><p>This is good thinking and a creative approach. Now the problem might be, that the hydrogen is in gaseous form, so force-feeding it to the 2nd stage rocket engine might become a problem.</p><p>Has this kind of configuration been seen before? Using the hydrogen first as the LTA component, then rocket fuel for the 2nd stage?&nbsp;</p>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Did I get this right; for orbital operation the first stage would use hydrogen as the LTA component providing lift to certain altitude. 2nd stage would then use the same hydrogen as rocket fuel to propel the vehicle to certain speed. The 3rd stage would be conventional upper stage?</DIV></p><p>That is correct&nbsp;</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>This is good thinking and a creative approach. Now the problem might be, that the hydrogen is in gaseous form, so force-feeding it to the 2nd stage rocket engine might become a problem.</DIV></p><p>Actually the rocket motor would be fed LH2 and LOX from&nbsp;liquid storage.&nbsp;&nbsp;The gaseous hydrogen is injected&nbsp;downstream of the rocket exhaust.&nbsp;&nbsp;</p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Has this kind of configuration been seen before? Using the hydrogen first as the LTA component, then rocket fuel for the 2nd stage?&nbsp; <br />Posted by aphh</DIV></p><p>Nothing close to my knowledge.</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Nothing close to my knowledge. <br /> Posted by BrianSlee</DIV></p><p>Well, congrats on a completely new idea. I think you're right, when you said the design has merit. You sound like you have already computed the basic numbers for the design, so building a model for the wind tunnel seems like the next step.</p><p>I just read elsewhere that venture capital is hard to come by for new aero-space designs, but I think we need new ideas. Perhaps offer the idea and design to a established aero-space corp?&nbsp;</p>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Well, congrats on a completely new idea. I think you're right, when you said the design has merit. You sound like you have already computed the basic numbers for the design, so building a model for the wind tunnel seems like the next step.I just read elsewhere that venture capital is hard to come by for new aero-space designs, but I think we need new ideas. Perhaps offer the idea and design to a established aero-space corp?&nbsp; <br />Posted by aphh</DIV><br /><br />aphh sincere thanks I consider that to be a high compliment.&nbsp; I think that the next step will entail CFDA and FEA to validate and refine the model.&nbsp; As far as teaming goes, as the paper states I am actively seeking partners wishing to collaborate.</p><p>&nbsp;</p><p>P.S. do you know anyone with a couple of old CRAY or SiliGs just sitting around idle?</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>aphh sincere thanks I consider that to be a high compliment.&nbsp; I think that the next step will entail CFDA and FEA to valiadte and refine the model.&nbsp; As far as teaming goes, as the paper states I am actively seeking partners wishing to collaborate.&nbsp;Posted by BrianSlee</DIV><br /><br />Please explain your acronyms. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Please explain your acronyms. <br />Posted by MeteorWayne</DIV><br /><br />Apologies</p><p>CFDA - Computerized Fluid Dynamics Analysis</p><p>FEA - Finite Element Analysis</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>aphh sincere thanks I consider that to be a high compliment.&nbsp; I think that the next step will entail CFDA and FEA to validate and refine the model.&nbsp; As far as teaming goes, as the paper states I am actively seeking partners wishing to collaborate.&nbsp;P.S. do you know anyone with a couple of old CRAY or SiliGs just sitting around idle? <br /> Posted by BrianSlee</DIV></p><p>Unfortunately not.</p><p>But a suggestion to improve the safety, since hydrogen is such a volatile element, would it make sense to design the blimp so that the LTA components would be divided in two sections, the outer layer would be filled with helium, which would enclose the hydrogen segments completely. This way hydrogen would never be able to get in contact with air to form a combustible mixture?</p><p>I know it would reduce the payload capacity, but so far to my knowledge every hydrogen blimp has eventually caught fire no matter what they did to prevent the fire.&nbsp; &nbsp;</p>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Unfortunately not.But a suggestion to improve the safety, since hydrogen is such a volatile element, would it make sense to design the blimp so that the LTA components would be divided in two sections, the outer layer would be filled with helium, which would enclose the hydrogen segments completely. This way hydrogen would never be able to get in contact with air to form a combustible mixture?I know it would reduce the payload capacity, but so far to my knowledge every hydrogen blimp has eventually caught fire no matter what they did to prevent the fire.&nbsp; &nbsp; <br />Posted by aphh</DIV><br /><br />To my kowledge hydrogen and helium aproximate pretty well for purposes of lift and helium would make an excellent inert barrier.&nbsp; I can also envision applications that would use only helium for safety reasons.&nbsp; E.G. civillian air transport <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>To my kowledge hydrogen and helium aproximate pretty well for purposes of lift and helium would make an excellent inert barrier.&nbsp; I can also envision applications that would use only helium for safety reasons.&nbsp; E.G. civillian air transport <br /> Posted by BrianSlee</DIV></p><p>The outer layer filled with helium would not necessarily need to have large volume. But in the case of rupture in either the hydrogen section or the helium section, no hydrogen/air mixture could be formed.&nbsp;</p>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The outer layer filled with helium would not necessarily need to have large volume. But in the case of rupture in either the hydrogen section or the helium section, no hydrogen/air mixture could be formed.&nbsp; <br />Posted by aphh</DIV></p><p>I would say that type of design feature in combination with slight positive pressure in the envelopes would greatly enhance safety.</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[Mee_n_Mac]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;all feedback is welcomed. <br />Posted by <strong>BrianSlee</strong></DIV><br /><br />If I've understood the concept correctly then what you'd hope to do is raise the launch site to 20,000 ft and give it an initial velocity of maybe 500mph; kind of like launching from a tall mountain. So how much mass does that actually save ?&nbsp; IOW for every kg put into orbit, how many kg of fuel (excluding that for&nbsp;the lifting platform) is needed ?&nbsp; How does this compare to what we now do ?&nbsp; I seem to recall some arguments presented in the M&L forum that most of the fuel is used to get to orbital velocity with only a small % being wasted to fight the drag of going through the lower atmosphere.&nbsp; Mind you "recovering" even a small % might be useful if it could be done cheaply enough. <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If I've understood the concept correctly then what you'd hope to do is raise the launch site to 20,000 ft and give it an initial velocity of maybe 500mph; kind of like launching from a tall mountain. So how much mass does that actually save ?&nbsp; IOW for every kg put into orbit, how many kg of fuel (excluding that for&nbsp;the lifting platform) is needed ?&nbsp; How does this compare to what we now do ?&nbsp; I seem to recall some arguments presented in the M&L forum that most of the fuel is used to get to orbital velocity with only a small % being wasted to fight the drag of going through the lower atmosphere.&nbsp; Mind you "recovering" even a small % might be useful if it could be done cheaply enough. <br />Posted by Mee_n_Mac</DIV><br /><br />Mee_n_Mac&nbsp; you have missed the concept a little but your question is still valid.</p><p>If the system were used to lift a rocket with a wet weight of 500 tons to its release point it would be at 80,000 ft with a velocity of app 250 m/s</p><p>assuming a realistic delta-v of 10K/s for orbital insertion</p><p>first subtract the delta-v of 250 m/s for forward velocity which leaves 9750 m/s </p><p>Using the formula for potential energy</p><p><table border="0" cellspacing="0" cellpadding="0" width="371" style="width:279pt;border-collapse:collapse"><tbody><tr height="21" style="height:15.75pt"><td class="xl25" colspan="5" width="371" height="21" style="width:279pt;height:15.75pt;background-color:transparent;border:#f0f0f0"><strong><font size="2"><font face="Arial">Potential Energy U = mgh = (k<font class="font8">_g</font><font class="font5">)(9.8 m/s</font><font class="font7">²</font><font class="font5">)(h</font><font class="font8">_m</font><font class="font5">) =<span>&nbsp;</span></font></font></font></strong>

 

[aphh]

<p>I'm still not quite sure if I have understood the concept fully,</p><p>is the blimp stage going to accelerate to orbital velocity or is it merely a launch platform for the rocket stages? Wouldn't it be better if the blimp itself didn't go to orbit, but just the payload?</p><p>As per your calculcations, relatively large 2nd stage could be lifted and boosted. The rocket stages could include a small shuttle type craft with heatshield and OMS to operate and return from the orbit while the blimp would return to the port after lifting and boosting the payload?&nbsp;</p>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm still not quite sure if I have understood the concept fully,is the blimp stage going to accelerate to orbital velocity or is it merely a launch platform for the rocket stages? Wouldn't it be better if the blimp itself didn't go to orbit, but just the payload?As per your calculcations, relatively large 2nd stage could be lifted and boosted. The rocket stages could include a small shuttle type craft with heatshield and OMS to operate and return from the orbit while the blimp would return to the port after lifting and boosting the payload?&nbsp; <br />Posted by aphh</DIV><br /><br />aphh staging will probably be the most efficient method of operation in terms of mass fraction. <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[BrianSlee]

<p>aphh sorry for the shortened reply I was engaged with other activities yesterday.&nbsp;</p><p>More detail&nbsp;</p><p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm still not quite sure if I have understood the concept fully,is the blimp stage going to accelerate to orbital velocity or is it merely a launch platform for the rocket stages? </DIV></p><p>The short answer is that I believe the system, properly operated and configured, would be capable of SSTO operation.&nbsp; </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Wouldn't it be better if the blimp itself didn't go to orbit, but just the payload?</DIV></p><p>&nbsp;That is an answer that will require more detailed analysis to determine the most effective and cost efficient method of operation.&nbsp; </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>As per your calculcations, relatively large 2nd stage could be lifted and boosted. The rocket stages could include a small shuttle type craft with heatshield and OMS to operate and return from the orbit while the blimp would return to the port after lifting and boosting the payload?<br /><br />Posted by aphh</DIV><br /><br />That is definitely a design consideration.</p><p>I would want to do an SSTO version if for no other reason just to prove it can be done ;O)</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[aphh]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I would want to do an SSTO version if for no other reason just to prove it can be done ;O) <br /> Posted by BrianSlee</DIV></p><p>If I may suggest, I'd first try to configure and offer the blimp as a airborne platform for rocket launches or just an alternative method for air travel/cargo delivery. You might get more traction for the idea.</p><p>Even if it was possible to orbit such a large vessel, returning might turn out to be impossible. Heat-shielding that much surface area would be costly and limit the payload capacity. &nbsp;</p>

 

[BrianSlee]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If I may suggest, I'd first try to configure and offer the blimp as a airborne platform for rocket launches or just an alternative method for air travel/cargo delivery. You might get more traction for the idea.Even if it was possible to orbit such a large vessel, returning might turn out to be impossible. Heat-shielding that much surface area would be costly and limit the payload capacity. &nbsp; <br />Posted by aphh</DIV><br /><br />aphh I wholeheartedly agree with your assesment.&nbsp; That is the main reason I split the propulsion section.&nbsp; I classified the rocket powered lift option as being in the middle of the risk profile and called it high simply for the fact that there is no past history to draw upon in this area for comparative analysis even though I am reasonably sure that I could accomplish that as a minimum design criteria.&nbsp; I have thoughts on thermal management for an SSTO version but am not ready to discuss them at the present because I would need a lot more detailed data to draw upon for conclusions.&nbsp; I am already hanging out there pretty far so I will try not to push my luck. <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>