![]() ![]() Time will tell which one of these PoV's is accurate. I'll need to update my ways-to-guarantee-project-failure list. I had never considered the possibility that they also selected a project leader who belief in themself could have vastly outstripped their ability to execute. I had always thought the X33 failed due to LM's over-promising undercooked technology and staffing the programme with b-team engineering talent to ensure failure. Of course they may be choosing to show off that aspect of the design with investors without making any public references to it, although I've never seen any other startups I'm aware of do this. Such a development would be a major breakthrough and would be valuable IP, and would truly be "disruptive." The patent makes no reference to any such material or technique. a)That Radian have acquired (or developed) in total secrecy a structural architecture that makes much more efficient use of existing materials, or they have developed structural materials that are radically better than CFRP, or any other known materials*. The implication of this (which a freshman aeronautical engineering student should have been competent to do) are. Boeing really did know what they were talking about when they designed RASV. ![]() There really is Hydrogen and everything else. And we haven't discussed the mass of the escape pod or the TPS yet. Rerunning the calculation with Dunns value for LH2 gives you 18.34%. This gives a structural fraction (for everything, vehicle, landing gear, all payload) of 12.25% That's 1.75% below the best ever achieved structural fraction for a winged vehicle. Using Dunns figure for Methalox of 368.3sec using a 20MPa (2900Psi) chamber pressure and 100:1 expansion ratio and run the rocket equation. Assume the sled removes 200m/s that leaves 7585m/s. So all you need to work out the mission is to dial in the altitude, subtract sled speed at seperation, and that's the target delta V. So arguably the best design/build team in the industry for one-off aircraft, lead by a designer who'd spent his lifetime acquiring (and using) the best techniques for composite construction available gets you a design that packs everything into 14% of GTOW Let's suppose however that between the sled launch and the wings aerodynamic lift all launch losses are cancelled. With more than a decade more experience SC got the GF up to 86%. Not having to cope with re-entry heating helped the mass as well, as did no major concessions for repair/maintain/oper-ability. The GF had very low stress margins, a very low thrust to weight ratio and a cruise speed of about M0.5 (roughly 1/46 of orbital velocity at 200Km), so no transonic buffeting or drag rise to deal with. It was built by Scaled Composites who also beat the previous 2 person aircraft to do this flight, Voyager. Aircraft don't really seem to have a "mass fraction" but they do have a "Fuel fraction" AFAIK the best of these ws for the Virgin Atlantic Global Flyer which Steve Fossett used to circumnavigate the world. In chemistry, g/cm 3 is more commonly used.Quote from: john smith 19 on 09:45 am I've been offline for some time but I did crunch some numbers for this. The density of water is about 1000 kg/m 3 or 1 g/cm 3, because the size of the gram was originally based on the mass of a cubic centimetre of water. 1 kg/m 3 ≈ 0.1604 oz/ imp gal (approximately).It is defined by dividing the SI unit of mass, the kilogram, by the SI unit of volume, the cubic metre. m −3, or kg/m 3) is the unit of density in the International System of Units (SI). ![]()
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