Recent content by spiralcopter

According to Hunnicutt's book on American heavy tank development, at least one of the prototypes of the T29 heavy tank was fitted with an Allison V1710 connected to a CD-850 transmission. That transmission is interesting because even though it started out as a heavy tank transmission, more...

We have some confusion as what is a cannon and what is a machine-gun. Some countries changed the definitions a bit but in general machine guns were under 20mm and cannon were 20mm and up. 15mm guns are a bit iffy. One problem with using this as a demarcating for what and what is not an...

Yikes, I didn't realize it was that low. So definitely no superchargers!

My point is that reverse-engineering aircraft was not the fastest way to get aircraft into service at all. The practical problems caused by not having access to the original blueprints and engineers are quite significant. Aircraft technology was moving very, very fast in WWII...

Practically speaking? In the 1940s the difference between reverse engineering and license production was huge. To reverse-engineer an aircraft, the factory is going to need a few examples of the plane. They're going to need to measure damn near everything, and they're going to need to measure...

Doesn't the Sabre have a built-in combiner/reduction gear? Meteors have the reduction gear removed if memory serves; the input speed that a tank transmission's gearing needs is quite different than the input speed a constant-speed propeller needs. I'm not sure that aero piston engines are a...

Yes, I am talking about yaw stability. I thought of it when I read an article on the F-35 SWAT weight-reduction program. One of the things Lockheed Martin engineers switched from the X-35 to the F-35 was that on the X-35 the nose landing gear is covered by a single door while on the F-35 there...

Putting the radiator under the engine in a single-engine fighter seems to have a lot of technical merits, such as keeping the radiator and engine closer together. On the other hand, surely having a big, deep chin radiator like on a P-40 or Typhoon increases the side area in front of the CG of...

In your average gas turbine engine, about 60-70% of the energy harvested by the turbines goes straight back into the compressors. So, in the case of, say, an LM1500 industrial gas turbine (basically a J79 but not in an airplane) that 15,000 horsepower is actually a fairly small percentage...

It occurred to me that the Japanese license-built HA-40 engines, being a licensed copy of the DB-601A, should have had fuel injection. Did the Japanese show any enthusiasm for this technology elsewhere? One would think that being given the blueprints to a fuel injected engine would be the...

Interesting point about twin turbines feeding to a common gearbox. As you say, it's quite common in helicopters. I would think that with turbines the vibration problems are much smaller, however, because most of the movement is from rotating components. With piston engines most of the...

The Chrysler XI-2220 sixteen cylinder engine took power to the prop reduction from the center of the engine, essentially dividing it into two V-8s and reducing the torsional loads on the crankshaft. Wright's R-2160 took this one step further, having three separate crankshafts; one per 14...

Thanks all, especially Calum. I had read the enginehistory article on sleeve valves vs. poppet valves, and thought that their assessment was fairly scathing. They concluded that sleeve valves had categorically worse power density, but conceded a slight edge in knock limit thanks to greater...

It occurs to me that at extremely high RPMs, sleeve valves would have the advantage that they do not suffer from valve float, as the valves are positively driven rather than spring-loaded. Ducati motorcycle engines can be revved to over 10,000 RPM in part because they have positively driven...