The larger missiles have more powerful rocket engines and therefore larger and hotter exhaust plumes that do “BAD” things to rather sensistive things like aircraft skin panels.

Some of the earlier aircraft missile systems, (Genie, FALCON, and RASCAL come to mind) where launched using an extending rail system to place the missile at a slight distance from the aircraft to lessen the exhausts plume effects while still retainaing “positive” launch control of the missile during firing.
It should be noted that for a NON-COMBAT airframe you can add such things as spray-on ablative to ward off damage but you still want at least SOME distance between the airframes when the rockets light because of the interactions between the airframe slipstreams and the exhaust plume can have the hot exhaust following the slipsteam in some weird directions.
(This is a major reason you can’t ‘fire-up’ a rocket INSIDE an airframe like a C-141/5/17 because the slipstream around the open cargo bay tends to funnle the exhaust into a nice recirculation plume back into the cargo bay :::bleH:::)

The current “lanyard-and-trapeze” system of the AirLaunch/T-Space paper on choosing a carrier aircraft seems about the best system since it reveals how modifications to the 747-200 carrier aircraft are very similar to those need for conversion to an airial fire-tanker leading to a possilbe “triple-income” between launches with using the carreir aircraft as a fire-tanker, air freighter or launch carrier.

I should mention that both Glenn Olson and Dani Eder both proposed using a jet-powered VTVL (Olson) and jet-launch-assist (Eder) to enhance the abilitiys of launch vehicles. AS soon as I can unearth my information on the concepts I’ll post the summeries here.

Randy

The Mig-25 also reached Mach 3 and IIRC it did not use a lot of titanium. They used nickel steel instead. Heavier but cheaper. Nickel alloys are used in turbine blades so they can withstand a lot of heat. However going at that speed destroyed the engines. SR-71 had a hybrid turbojet/ramjet, not a turbojet.

It is a shame they destroyed the tooling for the SR-71. Perhaps we would have less sedate fighter planes now. There was a kind of regression on fighter speed since then, although thrust-to-weight ratios in jet engines got so much better.

”
Mike said:
“I’ve witnessed them returning from flights on multiple occasions with the mach meters pegged over mach 3. Significantly over.”

I have not heard this before, but it does not surprise me! I know ex-A-4 pilots who flew them beyond Mach-1 on occasion. Getting certified to do this regularly on a commercial operation is another matter, perhaps!

I wasn’t considering titanium; I would consider that a material for thermal resistance if not thermal protection. It’s use would drive up costs significantly anyway, wouldn’t it? (compared with say, aluminium or conventional composites) No doubt it could be used, if the cost wasn’t a concern.”

Titanium isn’t that expensive a material. Especially not today. My father, before he retired, was an engineer at Sturm Ruger, who, in addition to firearms, made Calloway’s Big Bertha golf club heads, in investment cast titanium. Smith & Wesson and Taurus both make pistol frames from titanium in a few models. Theres plenty of consumer products that use the metal today, from watches to golf clubs and beyond. The Russians in particular have some serious expertise in manufacturing with it. Once the cold war ended the cost of titanium material and knowledge about its manufacture dropped in cost in the west significantly.

You do have to know how to machine it, tooling for that can be a little more expensive, but really, the cost of materials and mill bits is hardly a percent of a percent in the grand scheme of a development project. Personally in my experience, composites are the expensive items.

If launching to an equatorial space station, it could potentially do so every say three hours from one launch site without any range.

The rocket equation makes for a good start, but the economic equation makes for a better finish.

I wasn’t considering titanium; I would consider that a material for thermal resistance if not thermal protection. It’s use would drive up costs significantly anyway, wouldn’t it? (compared with say, aluminium or conventional composites) No doubt it could be used, if the cost wasn’t a concern.

That said, titanium skin and frame with SHARP leading edge and nose cone materials allows for mach 7 flight at 100k ft.

Or weren’t you counting titanium as a traditional aerospace material? (and SHARP has been in use since the early 70′s in some ‘cough’ aerospace applications, so thats a pretty good tradition too)