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The Energiya booster is configurable to 400,000 lbs, and that exceeds the 285,000 lbs orbital lift capacity of Saturn V. This is not surprising, given that Energiya was designed decades later and was using the latest technologies.

There were only two flights of Energiya, compared to 32 of Saturn V, and it is not manufactured any more. However its technology is not only up to date, it is being actively used in other boosters. So if anyone wants to lift 175 tons to the orbit, it can be done. It only costs money. See here for available configurations.

If you really need to launch anything that heavy, it would be cheaper and smarter to pay for manufacturing of Energiya rather than for redesign and manufacturing of Saturn V, and you get more bang for the buck at the same time. Engines of that power that are time-tested and proven to be OK are invaluable.

Turbo-Jet (same turbo jet power as turbo-prop, but little or no "bypass" air. The main purpose of the intake fan is now to pressurize air at intake for combustion with jet fuel. Thrust comes from) can provide substantial power at high velocites. TurboJets are the big muscular loud as hell engines used on fighter planes.

Turbojet engines don't have any fans, so there is no bypass at all. They only have compressors and turbines. Probably the only aircraft the Air Force still flies with turbojets are T-38s and (maybe) some KC-135s that haven't yet been retrofitted with turbofans. (I thought the B-52 was still flying on turbojets, but this page and this page say otherwise...you learn something new every day.)

Turbofan engines have been used in fighters for at least the past 40 years. Fighters don't get the same high-bypass engines that you'll see on an airliner due to size constraints, but turbofan engines with smaller fans go back in fighters to at least the F-111, if not earlier. Current fighters powered by turbofans include the F-15, F-16, F-22, and F-117. The F119 engine used in the F-22 is even capable of supercruise.

Okay......your math here sounds good, but I think that you overlook a few points.

Your formula uses an arbitrary value of 400mph to get the horsepower from. The top speed of an F-16 is mach 2, or about 1524mph at sea level. Less at high altitudes. Using this speed we would get almost four times the power output.

However, given the nature of a jet engine, its thrust will decrease as airspeed increases, since it's thrust is based on throwing air out a nozzle. So we can assume that the engine will not be putting out maximum thrust at maximum speed.

From the Pratt and Whitney site, the thrust range of an F100-PW-220 engine is 23,770 - 29,160 lbs of force. Assuming (and this is a big assumption) that at top speed the engine is putting out minimum thrust, then solving the equation we get:

(23,770 x 1524)/550 x 1.47 = 96,821

So we get 96,821 HP at top speed. I do find it hard to believe that this much power is needed to overcome drag on an f-16 at mach 2, but who knows.....

If this did not happen and the tank completely emptied, he said that it could cause major damage to the shuttle's main engines.

The engine bell itself probably doesn't care, but it needs to cut off on low fuel because of these suckers:

http://www.pratt-whitney.com/prod_space_turbopumps .asp

At 36,000 RPM and a whole hell of a lot of horsepower in a small package, it could fail in a bad exploding-turbine way if it suddenly went from full load (pumping LOX or H2) to no load.

Not quite true - the engines for the F-22 Raptor are F119 Turbofans (http://www.pratt-whitney.com/prod_mil_f119.asp)
which enable the aircraft to achieve supersonic flight without afterburner (quite an achievement).

It's completely true. I didn't say you couldn't have turbofans that operated at supersonic speeds. I said that turbofans:

a) cannot reach really high supersonic speeds
b) are less efficient than turbojets at some mach number

This is all the result of the fact that airflow through the fan must be kept subsonic, or else there is a drastic loss of efficiency. If you look at supersonic turbofans like on the F-22, you'll notice the intakes I mentioned that slow down the flow to subsonic speeds before the air hits the fan blades.

A turbofan and turbojet are both turbine engines with a set of fan blades as the first thing the incoming air "sees" after the inlet. These aren't like propeller blades

Turbojets have no fan, they just have a compressor before the combustor. And the solidity ratio doesn't make that much of a difference, fans can be treated using the same theory as propellors. Like propellors, they suffer a drastic loss of thrust as the incoming air approaches sonic speeds.

Your description of turbofans versus turbojets is correct, but you have to consider why turbofans are more efficient. Basically, it's a result of the following two equations describing the jet exhaust:

Thrust = mass-flow-rate * velocity
Kinetic energy = 1/2 mass-flow-rate * velocity^2

As you can see, thrust increases linearly with both thrust and velocity, but the kinetic energy of the air increases quadratically with velocity and only linearly with mass. Any kinetic energy imparted into the exhaust air is basically wasted from the engine's point of view, so its desirable to minimize this residual energy. As you can see, you can double thrust by either doubling the mass-flow-rate or doubling the velocity. Both give you the same thrust, but the latter approach leaves twice as much residual energy in the exhaust.

Turbofans work on the principle of maximizing mass flow rate and minimizing exhaust velocity. Instead of moving a little bit of air at high speed through the core, they extract most of that core energy at the turbine, and use it to drive a fan that moves a lot of air at low speed through the bypass ducts. The result of this is that in a high-bypass ratio turbofan, the fan provides the vast majority of your thrust.

Now, it becomes obvious why turbofans don't work well at high supersonic speeds. The closer the flow through the fan gets to sonic, the less efficient the fan becomes at providing thrust. Since the fan provides most of the thrust of the engine, the engine suffers a drastic thrust loss.

>Fans, like all propellors, drastically lose efficiency...

Not quite true - the engines for the F-22 Raptor are F119 Turbofans (http://www.pratt-whitney.com/prod_mil_f119.asp)
which enable the aircraft to achieve supersonic flight without afterburner (quite an achievement).

A turbofan and turbojet are both turbine engines with a set of fan blades as the first thing the incoming air "sees" after the inlet. These aren't like propeller blades - the solidity ratio is much higher for the turbofan (unless you are talking about the unducted fans, which were really super-turboprops, and still didn't have that many blades compared to a typical turbofan).

The difference between a turbofan and a turbojet is that a turbofan has some air that bypasses the "core" of the engine (the combustors and turbine section). This (generally) results in a more efficient design, depending on altitude, conditions, etc. Overall, turbofans and turbojets are very similar in concept - the turbojet is really a turbofan with zero bypass air.

Don't take my word for it - here's a good explanation of the differences (with illustrations).

What is the air-speed velocity of an unladen A380 ?

(hint: you can't waffle on this since there is only one type!)

What? With Pratt-Whitnet engines or Rolls-Royce engines?

I for one live in Connecticut, and i know that we are a target for terrorists. For we have major plants for kaman areospace http://www.kamanaero.com/ , Pratt & Whitney http://www.pratt-whitney.com/, Sikorsky http://www.sikorsky.com/, a Navel base in New London http://www.subasenlon.navy.mil/, a nuclear sub http://www.allsands.com/History/Places/grotonconne ctic_tz_gn.htm, and finally, the company that makes all your viraga http://www.pfizer.com/

Unlike P&W's previous engines, however, this engine is not a jet, and is powered by Nuclear Fission.

P&W rocket engines like the RL-10 are not jets, they are pump fed rocket engines. Jets are air breathing by definition. The main differences between a nuclear engine and a traditional combustion engine is the source of the heat (nuclear vs. chemical) and single exhaust fluid source.

And, lest we should forget, there's also Pratt & Whitney.

Pratt & Whitney in East Hartford has a decent surplus store. The Web site ai'nt much, but the shop is intersting. Prices arent' that great on old PCs ($180 for 450MHz PII w/ 64MB RAM, $75 Ultra10 w/o hard drive), but they have tons of office equipment, odd aircraft engine tools, and other sundries.

That is pride fuckin' with me

I must point out that my employer, the American company, Pratt & Whitney, has been very involved in the development and manufacture of the RD-180; the RD-180 is the product of collaboration between P&W and the Russian company NPO Energomash. It is derived from the entirely Russian RD-170 though, read more about it here.

• Vibration: You're going to have to insulate the smeg out of the equipment
• Batteries: R/C planes use a bunch of battery juice as it is. Adding a `fly by camera' interface would probably double the battery requirements.
• Flying: Unless you're going to put in four cameras (along with instruments (altitude, artificial horizon, pitch/yaw/roll rate, etc)), you're going to have a cast iron bitch of a time controlling the beast. Think about how much information it takes for a real pilot in a real plane to fly - 360 degree vision, a dozen instruments, and his sense of equlibrium(sp?). To duplicate that in a {quarter|fith|tenth} scale model that flys at a simulated speed of 1000 mph (200 mph ground speed in a fifth-scale model) would be very, very expensive and very difficult to control. Not only that, but you'd likely need a friend watching the plane to tell you when it was about to pancake into the runway...