Request Combined rocket jet booster

[jaydog]

I remember reading about a booster idea that was supposed to be ultra cheap and very safe. It was a vertical booster with 8 to 12 F15 Jet Fighter engines in a circle around a small solid or liquid center stage. The F15 engines can be optimized to operate to 60,000 Feet where it approaches mach 2 or 1500 mph, the rocket booster then fires and gets the payload up to around 4,000 mph or faster at 150,000 feet and drops off. A drouge chute then opens and reorients craft so that the engines which are off act as air brakes., at 40,000 feet 4 f15 engines fire up and reorient craft to allow for a STOL LANDING...
Any ideas or someone who would be into that sort of design? In reality I think its an ingenious idea, and could be a cheap and easy small payload booster..

 

[RisingFury]

Booster to send stuff to orbit? Because 4000 mph at 150 000 feet ain't anywhere near orbital velocities.

Sounds pretty ridiculous to me, especially the "cheap" part.

 

[Urwumpe]

There is an add-on, which implements a similar concept, but I have forgotten it's file name... is not too old, but I had not the time to fly it often...ah thanks to the visual browsing feature, there it is:

[ame="http://www.orbithangar.com/searchid.php?ID=2817"]GTX Trailblazer version 0.81[/ame]

 

[jaydog]

A booster stage...

Sorry, Its not meant to get payload to orbit, its meant to get a second and possibly third stage out of lower atmosphere where they can then take over and boost into orbit.. Akin to a first stage like on apollo...

Cheap? Almost everything is off the shelf. And it runs on kerosene for most of its launch. F15 engines are pretty cheap, considuring you will get a huge amount of reuses out of one before teardown, say 300 hours? And theres plenty of them around along with mechanics trained in thier maintenence. The center rocket could be a castor or hybrid that is vectored. Its the electronics and structure that need to be custom designed and could raise the cost.


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Yep allready have the GTX, but its mega expensive to build... we talking about a heavy lift booster thats more or less a can with fans


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The design study said, most of a launch vehicles cost are in the first stage or booster section. Over 50 percent in fact. Also turbines are fully throttleable. Many rocket motors are not, and the ones that are become more costly. Besides why carry oxidiser for the first 60,000 feet when you can get it free?

 

[Andy44]

Sounds like a neat idea. You can run on umbilical kerosene for the engine start, too, and switch to internal tanks when the hold down bolts blow, for maximum performance.

I wonder about the landing, though, where is it going to land? In the Atlantic ocean? Unless you're launching over land, and there are no overland ranges in the US.

 

[jaydog]

How to land

As the booster gets descends into thicker air side panels deploy and retract much like speed brakes (used on x33) to adjust trajectory. this allows craft to execute a turn back to base which may be Im guessing 50 to 100 km distant. Upon descent to 40,000 the engines start and oddly enough start a gentle then almost verticle climb to point its forward speed drops to 0 at about 60,000 feet... intake redirector shrouds (much like airline thrust reversers) then activate allowing air to be injected into downward thrusting engines as booster descends to base. Note this vehicle doesnt need or use wings. In many ways its operation is like the X-33.
This is my theory, and its subject to screwing up bad...
:rofl:


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It may be easier just to turn the booster back to base and when it gets over base flip the thing 180 degrees and let the engines slow it down and gradually tip the craft for vertical landing.


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umbilical before launch is good idea because they can start all engines and wait till they settle down and are all working b4 throttle up. Original designer of this idea said to use a kerosene / lox rocket in the center, so you could use same fuel as jet engines. But I figured if your going to go thru that why not just use a solid motor. I guess whichever would be the least weight.

 

[AstroCam]

Probably for landing use solid-fuel retro rockets. Shutting down and restarting 4 jet engines in flight is a wee bit risky.....

Yak-38: Proof of the fact

 

[Andy44]

Doing an RTLS recovery suddenly makes this a whole lot more complicated and expensive than it started out as.

 

[AstroCam]

Get some jet engines that are about to be scrapped anyway, add solid fuel boosters, duct tape the lot together.... This >could< be a good way to recycle flight hardware near the end of it's life - IMHO, launching from a site in the Nevada desert might be a good idea - if the boosters just going straight up, you wouldn't need much of a retreival system, just a GPS beacon, speed brake flaps and a parachute

 

[jaydog]

Back from doing research

After doing 3 years of research hsnap: I figured SR-71 engines would do the trick as they go into ram mode at higher speeds and they could simply parachute back as they only weigh 6,000 lb. each Of course the thought of them being augmented by hot lox might help them work better at higher altitudes. I put a photo of a falcon 9 (gliders, who I hope doesnt mind) with the engines installed, in my albums. I have a message out to moach as hes done some accurate calculations for air engine operation. Maybe we can get this thing flying.

 

[Sky Captain]

Not sure how effective this would be. Jet engines have poor thrust to weight ratio compared to rocket engines and fueled rocket stages are heavy. Each f15 engine with afterburner on produces 111 kN, suppose you have 12 so it is only 1332 kN total. This contraption could lift only small rockets like Falcon1 or Minotaur. Then there is question why bother with jets when 2 cheap strap on srbs could offer much better performance for liftoff assist.

 

[C3PO]

If you want to do high altitude air launches, stick some wings on the 1'st stage. That will solve your 1'st stage recovery. White Knight on steroids anyone? :lol:

 

[jaydog]

Yep smaller rockets only

Yes it is only for small rockets, but that said it increases launch ability in many ways. Its reusability is what makes it cheaper in the long run than any other technology. Wings cost to much to engineer and build and add many other variables.
Though large a falcon 9 produces 5,000 kN (1,100,000 lb thrust) at sea level. 8 SR-71 Engines produce 280,000 lbs of thrust after you remove their weight from the equation. This is a 25 % increase for say 1-2 minutes of the most critical time of launch.

What it could do for a pegasus is more telling, Stargazer altitude is 40,000 feet, Speed Mach .85 Vector angle of launch horizontal

SR-71 Boost Launch altitude 85,000 feet, speed mach 3.2 , vector angle of launch any you choose, as modulating thrust of engines allows yaw/pitch control.
Pegasus eats a lot of delta v just getting itself turned to a higher inclination.

one other thing... crew and equipment
Stargazer crew etc, 20-30 people. an airliner
SR-Launch crew, probably 10. small concrete pad a truck with a crane for retrieval.

Im not anywhere smart enough to figure out what the extra delta v would do for payload or orbit energy. Someone with calculations know how is needed for that uglyness.

 

[Maquis]

You should take a look at Skylon concept.

 

[Izack]

You should take a look at Skylon concept.

If he's done three years of research on this, it may be safe to assume he's already seen that.

Besides, this is completely different from Skylon.

 

[T.Neo]

I think something like Skylon would be better than this; there, it is horizontal takeoff, with the lift in the jet-powered portion of the ascent provided by the wings rather than the engines.

I don't know why you would try to launch something vertically on jet engines. That's the job for rockets; jets are better, at saving LOX (and fuel) in the lower atmosphere.

 

[jaydog]

on wikipedia they list air launch parameters for pegasus. Altitude is 10% of desired orbit altitude, Speed at launch is 3% of orbit speed. Now my engineers figured this out, with jet booster altitude is over 20 % percent of orbit and speed is now 12% percent of orbit. With these percentage increases in hand it figures to something like 20% payload increase from 1000 pounds to 1200.

With 8 Jet boosters on a Falcon 1E the jets can actually lift the whole vehicle with a 2:1 thrust/weight ratio. Thats packing some power, estimated payload increase to stable orbit is 30%. from 2100 pounds to 2700 pounds. Not to shabby


:thumbup:

 

[jaydog]

Recovery

The engine group or pack could all be hooked together with 2 ring trusses circumventing the rocket body. A kerosene tank and parachute would be attached on the lower center portion. A drogue chute might be needed to stabilize and right the engine pack on the way down, before the big chute opens. It may be good to have an inflatable bag deploy on bottom to absorb ground impact. :rofl:

 

[Urwumpe]

SR-71 Boost Launch altitude 85,000 feet, speed mach 3.2 , vector angle of launch any you choose, as modulating thrust of engines allows yaw/pitch control.
Pegasus eats a lot of delta v just getting itself turned to a higher inclination.

Complaint: The engines are too close to the rocket body and have no chance catching the nose shock wave. Their effectivity will be very poor, not comparable to a normal SR-71.

You would need approximately the same geometry as a SR-71 for that, at least by the position of the engines to the center line.

Maybe you should also think about another option...designing a rocket shape around the inlet geometry of a SR-71. Not scaling the engine up, but practically just wrapping an annular Ramjet around a rocket core. With the position of the surrounding ramjet changing for catching the nose shock.

 

[jaydog]

Good ideas

I think your right. Was wondering does air not move at same speed behind the shockwave? Other ramjet propelled rockets such as Nike (i think it was) did standoff the engine nacelle a bit from body so I guess that would be a requirement. Actually that might not be a bad thing because in the strap on configuration where it goes around the rocket body, that extra girth could be used to house fuel and maybe even the chutes. Also hard turns are bad things in ram mode from what i gather. So pitch adjustments would have to be very slow and smooth. I dont know if orbiter could even emulate that without some serious coding.

---------- Post added at 08:56 PM ---------- Previous post was at 08:52 PM ----------

err emulate engine starving that is.