X-106 "Christa", the Hyper Dart

[annodomini2]

<blockquote><font class="small">In reply to:</font><hr /><p>Quite so. Modern health management software is a lot better than it used to be, and most sensor modules today can be IP network addressable devices with self diagonostics. Rutan developed a pretty good system for SS1 based on the X-Plane sim software. Essentially, though most all of the electronics is stuff that will be totally unnecessary for us. <p><hr /></p></p></blockquote><br /><br />Ethernet is no good for space.<br /><br />Its not a fault tolerant network, there are space specific network controllers, but they are $50,000 a unit (stupid money really).<br /><br />Better option would be a standard known as CAN (Controller Automotive Network) and is used in all modern cars with electronics. <br /><br />It is a fault tolerant network designed for the harsh environment of car engine bays (ok so its not space grade, but its better than ethernet).<br /><br />A lot of newer low cost satellites are using this system for sensors as controllers are very cheap, $2-3 in bulk and microcontrollers are available with it built in.<br /><br />Top speed is 1MBit/sec (same as most broadband connections) and so will be fine for sensors, just don't try using it for p2p in flight! <img src="/images/icons/wink.gif" /><br /><br />Be nice to see some drawings if you get this off the ground. <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

If that is what OCR stands for my scanner software has that capability, don't know if it can be used after the photo was scanned however would be worth a try if you wanted to send me a pdf. Also the new products (asphalt milling machines) we are designing at work are using CAN systems. All of the EE's at work rave about the system. Personally I don't have any expirence since I really only touch the current production products.

 

[mlorrey]

Okay, cool. My scanner here is an HP PSC2410 3 in 1, but it didn't come with OCR that I can find. I should have my website up this weekend, and will have files for you to download (the weight and balance report, zipped, is like 44 megs, so emailing isn't going to work).<br /><br />

 

[mlorrey]

Annodomini2:<br />Why isn't ethernet, using shielded coax, not a viable networking protocol? Automotive wiring systems are unshielded, as well as exposed to lots of dirt and grime, which is why they need lots of fault tolerance. I doubt one would want to use any signal wiring that would not be shielded against radiation related transients and interference. <br /><br />CAN is actually Controller Area Network, and while it is used for automotive applications, I am concerned that it may not be a fast enough protocol to deal with hypersonic propulsion issues. The amount of time one deals with in sensing and responding to impending ramjet unstart conditions may be too fast for a mere 1 Mb network speeds.

 

[annodomini2]

<blockquote><font class="small">In reply to:</font><hr /><p>Annodomini2: <br />Why isn't ethernet, using shielded coax, not a viable networking protocol? Automotive wiring systems are unshielded, as well as exposed to lots of dirt and grime, which is why they need lots of fault tolerance. I doubt one would want to use any signal wiring that would not be shielded against radiation related transients and interference. <p><hr /></p></p></blockquote><br /><br />It's not just the protocol, its the electronic hardware and the wiring configuration, CAN uses a differential twisted pair configuration, which actively compensates for interference by design, given the usage intended for you're application additional sheilding may be prudent.<br /><br />Ethernet was designed to link PC's together, not for harsh enviroments, 99% of CAN hardware is adaptive to fault conditions inherently, with ethernet you would have to code a specific additional protocol to support this functionality, taking up a lot of bandwidth and significantly increasing your processor loading. <br /><br />Even then you would probably not support some of the features inherent in CAN and other fault tolerent networking systems.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>CAN is actually Controller Area Network<p><hr /></p></p></blockquote><br />Sorry yes you are correct!<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p> and while it is used for automotive applications, I am concerned that it may not be a fast enough protocol to deal with hypersonic propulsion issues. The amount of time one deals with in sensing and responding to impending ramjet unstart conditions may be too fast for a mere 1 Mb network speeds. <p><hr /></p></p></blockquote><br /><br />Depends on your operating frequency of the controller you are using to control you're engine, if the engine required its own bus, then seprerate the buses for different systems, if more bandwidth is required, then there are really two options;<br /><br />1. Multipl <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Only the shuttle uses three computer systems. None of the military aircraft I ever worked on had triple redundancy in anything.

 

[annodomini2]

<blockquote><font class="small">In reply to:</font><hr /><p>Only the shuttle uses three computer systems. None of the military aircraft I ever worked on had triple redundancy in anything.<p><hr /></p></p></blockquote><br /><br />All commercial aircraft are required to run triple redundant systems, most run 4. Military aircraft obviously come under different rules and the new space orientated systems obviously require different regulations due to 'other' risk factors involved.<br /><br />However with regards to your system, I would question what regulations it would come under.<br /><br />I'm guessing you're in the US, but it wouldn't be a military aircraft as the military isn't operating it, I'm guessing you would have to check with the FAA with regards to that.<br /><br />Although it could give you at least some peace of mind knowing there's a backup in place in case of a problem. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

I also know that small aircraft don't have this requirement, either. It appears to only be a requirement for large passenger airliners.<br /><br />The X-106 would be classified as an experimental aircraft or experimental spacecraft, because it would not be under mass production on a production line, nor a kit airplane.

 

[mlorrey]

Okay, based on the weight and balance data I got from Convair archives people, I've reworked the numbers. I've added a LOX tank to the dorsal fin stub which is used for takeoff up to ramjet speed. I've expanded the main LOX tank. New GLOW (higher, more propellant), lower dry weight (better airframe numbers from the source).<br /><br />Given up on the vert stab for payloads, the vacated radar/avionics bay and nose cone is large enough to accomodate 500 lb in cargo easily. I've added 1,000 lb to the airframe for TPS (going from low density aluminum skin to denser metal matrix, titanium, and lower density C-C with dense inconel anchors). TPS will be buffered from aluminum parts of airframe by ceramic and/or lexan blankets under TPS panels.<br /><br />Vehicle is now still lighter than expected empty, with more fuel, so the mass fraction is now up to .84, quite generous for plenty of cross range in orbit.<br /><br />Launch wing loading is now about the same as the STS orbiter is ON LANDING, which is about 7 lbs/ft^2 higher than a Learjet 60. Reentry/landing wing loading of X-106 is now less than half that of the X-33, or about equal to a Cessna 172's wing loading. This puppy is going to float home. She'll be really sweet skipping off the upper atmosphere till the cows come home, she might not ever want to come down... <img src="/images/icons/wink.gif" /><br /><br />Specs:<br />Length:75.8 ft.<br />Wingspan: 38.5 ft<br />Height: 15.7 ft<br />Wing Area: 1030 ft^2<br />Fuel, Main:12529 kg (27622 lb)<br />.........Belly: 2313kg (5100 lb)<br />LOX: 15,785 kg (34,801 lb)<br />........ Dorsal: 2267kg (5000 lb)<br />H2O2: 5,000 kg (11,000 lb) max<br />Tot. Prop.: 37,894kg (83,423 lb) <br />RCS Fuel: 100 lb<br /><br />Thrust, Ramjet: 75,000 lb<br />Ramjet mass: 1,500<br />Avg Isp, Ramjet: 1500 sec.<br /><br />Thrust, Main: 80,000 lb<br />Avg Isp, Main: 450 sec<br />Main engine mass: 700 lb<br /><br />Airframe Mass:11,000 lb<br />TPS: 1,000 lb<br />Gross dry mass: 14,200 lb<br />Passenger Mass: 400 lb<br />Max Payl

 

[rocketman5000]

so far is it just you working on this project?

 

[mlorrey]

So far, yes, though I've got some people interested.<br /><br />I just talked to some folks today on this with a company that can produce the LOX tank and the RCS system. I'll be talking more with them tomorrow.

 

[rocketman5000]

They wouldn't happen to be the same people that you developed X plane software for would they?

 

[gunsandrockets]

If your prefered propulsion is not available or unworkable the suggested GLOW is low enough for alternative methods. Perhaps towed air launch and use of the South Korean rocketplane's 25,000 lb thrust methane rocket engine.<br /><br />http://www.candspace.com/

 

[mlorrey]

Methane requires cryogenic pressurized tanks. We don't have the space for two such tanks, we'd have to turn the LOX tank into a methane tank and use the fuel tanks for peroxide, which would give poor Isp. I don't know if we'd be able to use peroxide (the Korean engine is regen cooled). <br /><br />On the flip side, its nozzle diameter is small enough that we could fit four engines would fit in the same space as the Merlin, but the mass of just under 200 kg would mean more than doubling the engines mass over the Merlin, ergo T/W ratio would be half that of the Merlin.<br /><br />

 

[mlorrey]

Here's the latest iteration. I've added several possible ramjet concepts: rocket ejector cowling, double underbelly, and double underwing. The underwing concept can be combined with the single underbelly, double underbelly, or the rocket ejector cowling concept.<br /><br />The underwing ramjets can be either parachute recovered, or deploy swing wings and control stabs after being dropped, to return to base for a controlled landing. Parachutes are a quick and easy method that will incur large operational costs recovering the engines from the ocean, while the winged recovery mode would take more development capital but would cost less operationally in the long run. Landing in the ocean is less likely to damage the engines from impact, though corrosion is an issue. Landing on a runway runs risks of crashing, control failures, etc. though if near the ocean, a controlled ditch in shallow water is always an option.<br /><br />I've included a slightly unsymmetrical LOX tank that may fit the airframe ribbing at the front of the engine bay a bit better than the prior version. The LOX tank has been lengthened.<br /><br />I've also added a droppable LOX tank to the center stab point, which is parachute recoverable. Payload bay is the purple area up in the nose. RCS tank has been moved to the under-cockpit avionics bay and thrusters mounted in the sides of the payload bay. Payload dimensions are 2.6' x 2.6' x 7.0'. As noted previously, empty weight is significantly less than previously predicted, allowing replacement of aircraft aluminum skin panels with denser materials capable of contributing to TPS, as well as extension of leading edge structure for a considerable strake of RCC.<br /><br />With low wing loading, the TPS should be more than sufficient for the flight regime this vehicle will experience, skip diving off the upper atmosphere repeatedly, cooling off between skips, dropping speed each time. This will be a much more gradual reentry than the STS Orbiter experiences, and eve

 

[rubicondsrv]

you may want to consider using aerogel for the insulation undes the TPS. it would be much lighter than the other options. it also is a better insulator. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

I've been considering it for areas not under compression from fasteners, and possibly to fill honeycomb structures, given its a better insulator than air. If there were an aerogel that could handle significant compressive loads, I'd even consider it for the fastener's insulating washers. As it is, insulating washers and RCC to airframe bushings will likely be something like hafnium diboride, which is dense, so I'd like an alternative.

 

[rocketman5000]

Taking a quick look at your photos, I had an idea that may or may not work depending on aerodynamic loads/dynamics. if you are dropping recoverable ramjets it could be possible to increase the size of the pod so that it would include fuel and be shaped into a lifting body eliminating the need for swing out wings that don't do anything on the launch except count for excess mass. You could have the ship (ramjets) glide down to a reasonable speed deploy a paragliding chute and airbags for landing. This could allow landing on dry land and decreased cost of recovery of the units. Additionally this could allow the pods to flyback to the launch sight of a designated recovery zone. Possible the area where they would be refit.

 

[mlorrey]

I thought of that, but there are issues, such as getting in the way of the landing gear, as well as the lifting body interfering with the wing of the plane. The hardpoint is pretty close to the LG, and I'm already concerned about packing more weight on this thing.<br /><br />Using a parachute recovery might be useful if we recover in the air, like with a C-130 or similar aircraft.<br /><br />An alternate idea is to just ditch em. Make some plain jane Bomarc style round ramjets, simple simple, and just have them mass produced with a simple MIPCC system built into the nose cone, and fly the hell out of them till they burnout, drop em, and go to pure rocket. I haven't calculated what the benefit of dropping the ramjet mass would be, but offhand it would reduce empty mass by 10%, so the mass fraction should go up to about .855 or so for the rocket phase of flight.<br /><br />Ramjets are very simple things: once you have the design down and the tooling made to produce them, they are very cheap things to make.<br /><br />Might just do that, along with a rocket ejector cowling for the rocket engine on takeoff, which could also be used as a ramjet after takeoff with the rocket engine off. We've got to keep the KISS principle here, we are shooting for 'good enough' not perfect.<br /><br />

 

[rocketman5000]

I agree with the good enough principle. It takes good engineering to keep a design simple and consequently cheap. If these ramjets were made well enough. Being essentially an empty tube it could be possible to land with parachute and not damage anything important on them. throw away the tube and keep the things like pumps and any sensors it might use. The peices that would be expensive, but highly reuseable. If the tube was made of steel it could asorb a lot of impact energy and allow a minimal parachute

 

[mlorrey]

gunsandrockets said: "Magic fuel - RP sprinkled with boron dust. <br /><br />In a different thread I asked you to produce any information with links about the use of such a fuel in a rocket engine and any test results. To date I have heard nothing in response and my own searches have been fruitless. "<br /><br />Check out the latest Aviation Leak: the Blackstar military space shuttle used boron gelled fuels, just like I plan on using. I have been vindicated by this.<br /><br />http://www.aviationnow.com/avnow/news/channel_awst_story.jsp?id=news/030606p1.xml<br /><br />"WORK ON THE ORBITER moved at a relatively slow pace until a "fuel breakthrough" was made, workers were told. Then, from 1990 through 1991, "we lived out there. It was a madhouse," a technician said. The new fuel was believed to be a boron-based gel having the consistency of toothpaste and high-energy characteristics, but occupying less volume than other fuels. "<br /><br />There you have it, folks. <br /><br />It also appears that top people at NASA were aware of the program:<br />"In 1994, NASA sources confirmed that two of the C-5s (Tail Nos. 00503 and 00504) were listed on NASA's inventory--although the aircraft did not "officially" exist, according to the agency's public records. Both transports apparently were deployed only upon orders from the administrator's office. The third oversized C-5 once had a red "CL" on its tail, and supposedly was used by the Central Intelligence Agency. All three C-5s may have been retired in recent years, according to a NASA contractor. "<br /><br />Thus I would take any criticism of this concept by NASA people and NASA contractor people on this forum as disinformation.<br />

 

[tomnackid]

I'm not sure I would assume "boron-based gel" is the same thing as your kerosene/elemental boron slurry. I don't think anyone disagreed with the concept of boron spiked fuel increasing isp--that's established in the literature. I myself disagreed with the idea that just dumping elemental boron powder into a tank of kerosene and feeding it through a rocket engine would solve your isp problems. I think I said something like "If it were that easy everyone would be doing it." Unless there is a massive "disinformation" program that reaches into every aspect of propulsion research we have to assume that a boron gel fuel/engine system is a complex piece of chemistry and technology that people probably won't be cobling together in their basement workshops for a while yet.

 

[shoogerbrugge]

It seems somebody has the same idea as you have. Well, not the fuel, just the air launched concept, recently revieled, more info overhere

 

[mlorrey]

Well, not the same concept. They're keeping the jet engines, air dropping an unmanned rocket with satellite. It is a good concept, though the unreusability of the rocket stage will keep its payload price up in current-market-price range. If they can recover and reload the rocket, that may be interesting. I suspect its orbital payload won't reach what we're planning.

 

[gunsandrockets]

"Check out the latest Aviation Leak: the Blackstar military space shuttle used boron gelled fuels, just like I plan on using. I have been vindicated by this."<br /><br />First off Aviation Week isn't certain this vehicle really exists. Secondly the boron-gel fuel is a guess. Thirdly there is no information in the article quantifying the performance of the gel.<br /><br />So go ahead and claim 'vindication'. By myself I have finally found some data on boron additives and borane propellents for rocket engines, and that data does not support the scale of improved performance you claim.<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=missions&Number=459022&page=0&view=collapsed&sb=5&o=0<br /><br />