X-106 "Christa", the Hyper Dart

[mlorrey]

I've been refining my Blackhorse/RASCAL class design built out of an F-106B airframe with image and data below.<br />What is important is that I know where to get some F-106 airframes for approximately $24,000.00. This alone is a huge savings. The F-106 airframe was built to handle 9+ G's, and its wing is a super thin hypersonic airfoil delta, already with a 60 degree sweep. Adding a carbon-carbon 75 degree strake and other stuff to it would be rather easy.<br /><br />For those who missed my commentary in another thread on this, here is the idea: take an F-106, dump the J75 engine. Using RASCAL-type MIPCC on it might be easily possible, as one group proposed, but is IMHO insufficiently ambitious for the degree of proven technology sitting on the shelf out there.<br /><br />Instead, put a composite LOX tank in most of the engine bay. Seal up the air intakes, front and back, with a streamlined plug in front, and fill them as additional fuel tanks. Mount in the bottom of the engine bay, behind the wheelwells, a ramjet capable of mach 5-6 operation, minimum, with active cooling. Mount a SpaceX Merlin engine in the upper rear engine bay. Former weapons bay will be an additional fuel tank, and the wing tanks will be converted to holding H2O2, hydrogen peroxide, to be used for cooling the ramjet and as coolant/oxidant in an MIPCC rig used to extend the flight regime of the ramjet up to mach 7-8. There will likely be no need of any supersonic combustion, but it might become a possibility.<br /><br />We are not going to screw around with LH2. It is a terrible fuel for any vehicle with any significant aerodynamic flight regime, as the Suntan project amply demonstrated. Given the limits of todays materials, we are not going to need to operate in air breathing mode above mach 8, so the use of LH2 to fly any extensive supersonic combustion at higher stagnation temperatures is not needed. At Mach 6, the Merlin will ignite at a low thrust level to augment the ramjet, and MIPCC cooling wi

 

[j05h]

I really like the idea of using decommisioned aircraft for spaceflight. If rocket-racing takes off, I can definitely see converted fighters in a high-altitude class. For the vehicle you described, everything except the ramjet is off-the-shelf. A small-sat launcher could be designed using your F-106 and a small upper stage, all with existing components. A second vehicle could be designed around a standard jet engine and Merlin for airport-to-LEO, like the Blackhorse it would use aireal refuelling. This kind of converted fighter might be a good candidate for the aerospike "ramp" nozzles.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[mlorrey]

Read the details. This should be capable of SSTO RLV flight.<br /><br />Oh, btw, the grey areas of the vehicle are all specifically converted to carbon-carbon/Si-C materials. All underbody skin should be of such materials. This will save a significant amount of weight in the conversion process and provide sufficient TPS for skip-diving and reentry.<br /><br />I would also suggest that such vehicles may want to develop more extensive skipping maneuvers than that of the Shuttle. <br /><br />The predecessor design to this was my Lorrey Ballistijet simulation in X-Plane, which I've flown many a time on mach 23 skip-diving missions around the Earth on several orbits.

 

[spacefire]

have you done a Wt&B yet? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[mlorrey]

A weight and balance? No, not yet, that is what I'm planning to do next. As the LOX tank has scaled with the increase in the fuel tankage, I'm not expecting any huge shifts in CG, but the calcs will of course tell the tale. <br /><br />If the CG is too far forward, I can increase the area of the strakes significantly. I'm not too concerned with it shifting aft, as the 106's CG was pretty far forward, such that the A model's acceleration and peak speed were actually limited by the standard down nosing tendency of the tailless delta at top speed, thus the B model could accelerate and go faster than the A, since its CG was further back.<br /><br />At this point, the increase in the wing area the strake provides is offset by an increase in the area of the flaps and aelerons I built in to increase high AOA maneuverability, esp during reentry, so I'm not too concerned about changes in center of lift.<br /><br />An additional point: the design as it is has a mass fraction of 0.78. I am estimating an average effective Isp of about 660 secs, significantly above the 500 secs minimum necessary to make a .78 mass fraction vehicle orbital. At 660 secs, it can tolerate a .70 mass fraction, so there is an immense amount of payload and/or cross-range built into this design, provided that the propulsion systems perform as expected. This also means I can significantly increase strake area without the weight penalty damaging the SSTO status of this. With larger strake area it should have a shorter take-off and lower takeoff speed, as well as lower landing speed, due to lower wing loading.

 

[mcbethcg]

I like it.<br /><br />I don't think the ramjet will provide as much power as you predict here though.

 

[space_dreamer]

Mlorrey – I don’t have time for a longer post tonight, but I have to say that this looks like one most promising threads I’ve seen on these boards in ages!

 

[larrison]

We all don't agree on the "best" way to get into space. But none of our ideas really matter if that's all they are.<br />Has anyone thought about government grants or other funding to test some of these ideas (and frankly<br />I think are more impressive than some of the ones I've seen NASA propose.)

 

[mlorrey]

mcbethcg,<br />Okay, do you have some calculations to back up that belief? And are you talking peak thrust, or average thrust? Ramjet thrust does vary with mach number, all else being equal. And are you calculating with numbers for boronated RP-1, or just normal Jet A? Lets put some real math on the table here.<br /><br />For calcs, this image is 60 dpi, with a scale of 5' per inch. <br /><br />I'm very interested in serious discussion on this.<br /><br />As for gov't grants, the RASCAL program was cancelled, and Bush nixed all NASA RBCC programs. Unless someone knows of a black projet out there in need of help, I'm not optimistic there. Getting funding from angels, though is a possibility.<br /><br />I'd like to get a hold of 2-4 106 airframes to work on as the core project of what I'd like to get going here in NH, as the McAuliffe Space Academy. Get the "Alan Shepherd Space Port" opened at Pease Airport (formerly an FB-111 airbase) in Portsmouth, with the academy there sponsored by a college with an aviation/aerospace program like Daniel Webster College in Nashua does.<br /><br />There's plenty of money folks in this region who would back this sort of project (heck, Christa McAuliffe's husband is one of the most powerful lawyers in the state).

 

[gunsandrockets]

You mention the added RCC, but what of the thermal protection system for the rest of the craft? What is the total weight of all the TPS?

 

[gunsandrockets]

What is the power source, fuel cells? And how much mass?<br /><br />What is the mass of the life support system? What is the flight endurance?

 

[gunsandrockets]

Your vehicle has a rocket and a ramjet engine.<br /><br />"At Mach 6, the Merlin will ignite at a low thrust level to augment the ramjet..."<br /><br />So what propells your craft up to the airspeed that the ramjet would function?

 

[gunsandrockets]

Since your vehicle will gross about twice as much as the orginal F-106, won't the landing gear need replacing?

 

[mlorrey]

I expect takeoff to 450 kt would be accomplished either by launch sled, tow-launch (as Kellyspace demonstrated with the 106 already), airlaunch (a la WK2 or An-225) or through use of the Merlin engine at takeoff as well, or possibly just using some JATOs.<br /><br />The 106 has a preexisting 1950's era environmental control system to pressurize the cockpit and provide oxygen to crew up to very high altitude. This will likely be replaced with either a newer system, possibly something borrowed from the Russians, or else just augmented by peroxide surplus providing both O2 and power for the ECS. I have budgeted sufficient surplus peroxide (500 lb) for use in reentry cooling and orbital ECS.<br /><br />It is definitely something I'll be looking at myself, as ECS was one of my specializations in the USAF. <br /><br />Landing gear will likely need to be replaced with titanium in place of the steel structures currently used. This should provide sufficient additional strength for the added load.

 

[mlorrey]

I expect to strip the aluminum and steel sheetmetal skin of the airframe and replace it with CC/SiC on leading edges and underside, and Ti/Li on upper surfaces, possibly with boron carbide or boron nitride surface treatment. <br /><br />As the wings are wet wings, and will be holding peroxide, this should act as a thermal sink (the extra 500 lb) for the wing surfaces prior to it being used as a coolant by the ramjet during reentry.

 

[grooble]

Are you actually going to build this for real? Why not contact scaled composites with your idea? They might give you a grant or something, or NASA or the air force.

 

[mlorrey]

I'd really like to do this, though I'm not, as they say, capitalized to start doing it alone at the moment. As I mosey along refining the design and working out the numbers, I may shop the concept around. Mitchell Clapp would be a good guy to contact about this. Does anyone else have any suggestions?

 

[rocketman5000]

Work up a good design proposal. One that can state the finacial benefits to having this design. Write a business plan, there are plenty of free resources to get you started with this on the internet. Try to have answers for any questions that an investor might have for you. By posting here you can flush out a lot of those questions and come up with solutions for them. Try to be able to nail down a preliminary budget for materials and manpower. Your company would be a startup so likely you'll be working for room and board.<br /><br />Contact potential suppliers of parts that you'll need. Since the Ramjet is one componet that you can't purchase off the shelf spend time proving out the design. Figure out the materials you'll need flow rates of fuel etc. <br /><br />Get several partners to help you out. Some with techincal expertice and some with money. You'll want some preliminary testing done on scale models or computer simulations of the heating of the airframe during reentry. The biggest single hitch to a viable SSTO is the TPS. It consumes vast quantities of the dry mass fraction. <br /><br />Finally start to contact anyone you know that could get you money or could point you in a decent direction. State politicans are a great place to start asking for money. They like to bring businesses into their districts and or state in general and maybe able to get you breaks on facilities to house your plane. or Grant money for begining stages to attract more investors.

 

[spacefire]

common sense states that your spaceplane will end up much heavier than anticipated when you get to the detail-design stage. I suggest you make provisions for some sort of high-altitude inflight refueling procedure. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[mcbethcg]

"mcbethcg, <br />Okay, do you have some calculations to back up that belief? And are you talking peak thrust, or average thrust? Ramjet thrust does vary with mach number, all else being equal. And are you calculating with numbers for boronated RP-1, or just normal Jet A? Lets put some real math on the table here. "<br /><br />Nope. I am not a math guy.<br /><br />But I will say this. For some reason, NASA and the space agencies of China, Russia, Europe and a dozen other countries have sought ways to put things into space as cheaply as possible. <br /><br />Each country has assuredly looked at ways to build SSTO vehicles. Ramjets have been around about as long as liquid fuels rockets.<br /><br />I feel that something is probably wrong with your math, because your craft looks drastically undersized as far as fuel capacity goes.<br /><br />There have been several recent attempts to design SSTOs using combinations including ramjets, rockets, hybrids, etc. <br /><br />None of them had much hope of practical use.<br /><br />Your design does not appear particularly radical, so I simply think your math is wrong somewhere. I dont know where.<br /><br />But by analogy, imagine that someone showed you a design of a chevy vega with a turbocharged engine, and told you it would do 600 miles an hour. Assume the designer was some guy on the internet who claims to know the math. But YOU don't know the math regarding automobiles, but you know it looks underpowered even compared to cars that do half the speed. You would probably come to the conclusion that the proponent had made some error, somewhere. <br /><br />In your example, I assume it is in your estimation of the capabilities for the ramjet, because I know that ramjets have not been used sucessfully for this purpose even though they have been around since at least 1941. In addition, in the recent test of the X43, the thing was only able to accelerate for a few seconds after it had been boosted to very high altitude (IIRCC 300,000 feet)

 

[mlorrey]

Okay, firstly, ramjets have been used in missiles for decades. They don't get used exclusively in people-carrying aircraft primarily because of the issue of getting them going. However, if you consider that every afterburner on every turbojet and turbofan engine in history was essentially a ramjet, particularly the SR-71 engines which entirely shut off airflow to their turbines at supersonic speeds, then your assertion that 'ramjets have not been used' is entirely false.<br /><br />"looking at something" is not valid engineering critique. Go read the dozens of papers on various air breathing and TAV launcher proposals and projects that are available over the internet. I've pretty much read them all, gleaned what I saw to be useful knowledge of things to do and things to avoid, and have learned from the experts what the 'cold equations' of spaceflight dictate are necessary for a valid launcher.<br /><br />Nations like China, the US, etc have historically focused on rocket powered missiles is because missiles are very good at delivering nuclear weapons anywhere very fast, and just so happen to be dual-useful for space launch, so it is easy for a country to hide its WMD development research in an ostensibly "civilian" program, then transfer technology to military uses when it is refined.<br /><br />NASA, even, has done most of the research I've read up on in air-breathing launchers. They were ready to develop some really useful ones to follow-on the X-43A when Bush cancelled it (do a google on "GTX" and "RBCC" and start reading). NASA has developed the quad mode Rocket Based Combined Cycle engine in the wind tunnels to a very high degree of sophistication, and, like so many of their projects, it is essentially dead on the vine. <br /><br />I am essentially trying to crudely replicate what they've done with a ramjet and the Merlin engine.<br /><br />My mass calculations are NOT unrealistic. You are used to the humongous tanks needed by LH2 fuelled vehicles, due to hydrogens terri

 

[mcbethcg]

Well, maybe it would work. Thanks for the GTX info. But I have my doubts, still.

 

[gunsandrockets]

"and have estimated a 20% mass savings to the skin mass by removing the aluminum and steel skin and replacing it with CC/SiC and Ti/Li."<br /><br />I was not aware that steel made up any part of the skin of the F-106, where and of how much weight?<br /><br />As far as I can find the weight of reinforced carbon carbon thermal protection is quite heavy (44 kg/m2), which is partly why it is only used on limited areas of the space shuttle.<br /><br />http://www.centennialofflight.gov/essay/Evolution_of_Technology/TPS/Tech41G2.htm<br /><br /> Plus your own design shows added wing double delta strakes of carbon-carbon, so that is not replacement of original structure it is instead added structure, and therefore added weight.<br /><br />If the rest of the aluminum skin is stripped off and replaced with titanium that is only a partial answer for thermal protection. Even though the titanium might not soften under the heat of reentry the interior of the craft needs insulation from heat transfer from the hot skin. You need thermal blankets for that, and for which you have not made any accounting for that additional mass.<br /><br />In many ways the thermal conditions of your modified F-106 and the Space Shuttle are similar. Both are delta winged gliders with aluminum structure modified with TPS to survive reentry. Yet your design does not show the TPS of the Shuttle or account for the added mass. I suggest you may have seriously underestimated the mass requirements of TPS.<br /><br />http://www.centennialofflight.gov/essay/Evolution_of_Technology/TPS/Tech41.htm<br /><br />

 

[gunsandrockets]

Assuming your modified Merlin engine would achieve the higher ISP you estimate, you can't achieve that ISP with the same rating of 80.000 lb of thrust. A 40% increase of ISP while maintaining the same thrust would subject the Merlin engine to double the energy it normally operates under. Operating under the normal amount of energy plus increased ISP means a thrust reduction of 30% to about 56,000 lb of thrust. <br /><br />It's the pitiless equations of rocketry at work. Higher ISP engines have lower thrust to weight ratios. You yourself noted one such example, "While H2 gets you higher Isp, its thrust is lower for a given engine size." <br /><br /><br /><br /><br />

 

[gunsandrockets]

"I expect takeoff to 450 kt would be accomplished either by launch sled, tow-launch (as Kellyspace demonstrated with the 106 already), airlaunch (a la WK2 or An-225) or through use of the Merlin engine at takeoff as well, or possibly just using some JATOs."<br /><br />The Kellyspace tow launch concept always seemed like an excellent idea to me. <br /><br />You should stop refering to your vehicle as a SSTO however, unless the Merlin gets the vehicle up to ramjet speed. And if you do use the Merlin for takeoff, serious recalculation of performance will be needed. For one thing the Merlin will lose a lot of ISP operating at low altitude and use up a lot of fuel to accelerate the vehicle up to ramjet speed/altitude.<br />