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Discussion in 'Fred's House of Pancakes' started by cwerdna, Jan 31, 2012.
This is a photo of a model, not a real aircraft.
Airport Kid's explainations about gliders are pretty much on the money.
Gliders are considered an aircraft "category." Other categories would be: airplane, rotorcraft and lighter-than-air.
Glider ratings on a pilot's certificate used to be geared to the way the aircraft was able to get airborne; e.g., aerotow, ground launch and self-launch, (motor glider). A few years back the FAA dropped the requirement to have those airmen certificate limitations; instead, all one needs is to have an endorsement in their logbooks from an appropriately rated instructor in order to be legal.
Ultralight aircraft, by FAA definition, are:
used for recreation or sport purposes only
weight less than 254 lbs.
fuel capacity of 5 gallons
stall speed of 24 kts or less
maximum speed of 55 kts (approx 58 mph)
No pilot training nor a pilot's certificate is needed in order to operate an ultralight.
Exceeding any of these parameters will put the aircraft into an "experimental" category which requires the aircraft must be inspected, registered and have an "N-number," and the pilot must be certificated to at least a sport or private pilot rating.
Unfortunately, in my job as a FAA inspector, I do see a lot of "heavy" ultralights involved in accidents. These are due to lack of pilot training and unairworthy craft. Because they are operated out of pastures and fields in rural areas, most flights go unoticed--until we're called to an accident site.
It's not even that. It's an X-Plane creation, a virtual entity that exists only on computer screens. The version depicted was never built; what was built and flown was something quite a bit smaller with fewer than half the number of engines.
Giant multi-engined aircraft of that period suffered a serious problem: their propellors were fixed pitch, which in the event of an engine failure caused crippling drag from the windmilling prop, in some cases drag so severe the airplane couldn't hold altitude. As the number of engines increased, and the technology of the time what it was making engine failure a common occurrence, more engines increased the certainty that any flight would lose one, and probably drive the airplane to the ground.
It was for exactly that reason that Lindbergh deliberately made his Spirit of St. Louis a single engine airplane; it gave him the greatest probability of a successful flight. Any engine failure would have put him into the water; and adding engines only increased the likelihood that he'd have an engine failure.
It wasn't until the fully featherable propellor got perfected that multi-engine aircraft became truly practical.
interesting, I always thought NTSB handled accident investigation and FAA just handled pilot punishment (flight standards in OkC)
I think this was the technique Charles Lindbergh taught to US pilots in the Pacific theater to extend their range.
Lindbergh taught them to run leaner, lower RPM and higher manifold pressure. It put the engine in the sweat spot on the BSFC map for the power required for cruise. Much like a Prius does automatically.
Charles Lindbergh and the 475th Fighter Group
I don't know how this slipped by me. Sorry, Hyo, this is dead wrong. If it were true all commercial flight would be at altitudes just barely high enough to keep the noise level tolerable, but no higher.
Instead all commercial flying is conducted as high as possible, and not just to get atop the weather or catch favorable jetstreams (although those things are a bonus). Flying high reduces drag because the air is thinner, and efficiencies multiply as a result. Fuel consumption goes down and airspeed goes up.
Even my Cessna 180 improves 2gph between sea level & 10,000 feet, and that's with a simple unboosted carburetor. Boost (supercharging) improves things even more.
Time to climb does burn more fuel, but the length of time spent in climb is a fraction of the time spent in cruise, and high altitude cruise efficiencies more than compensate for the extra consumption of climb. And you get some of it back in descent as well.
The curve does bend back for air breathing engines once you've gotten into air so thin not even boost can keep the thing running, so nobody's flying commercial craft in outer space. 30,000 to 40,000 feet is about the best range for jets, 20,000 to 30,000 feet for boosted reciprocating engines.
Flat hatting just off the deck is fun, but it'll empty your tanks faster than any other mode of flight.
Don't be sorry. Thank you for the correction.
My initial assumption was that the Ekranoplan would use large amounts of fuel because it flies so low. When I read that it uses only half (maybe that was the part I should have questioned) I assumed my first thought was wrong.
Do we have a good idea what the 'mileage' of these monsters is? If it's significantly different from conventional aircraft, do we know why?
Lindbergh taught them to lean their engines. I am friends with one of the P38 pilots that he taught, so I have heard this story many times firsthand.
A flying aircraft expends energy to overcome two factors: 1)Creating lift, and 2) Overcoming drag.
Aerodynamic drag is non-linear. It goes up exponentially with speed. If you want to fly fast, you need to fly high in thin air. Low altitude isn't much of an issue if you keep to a modest speed.
WIG aircraft develop lift more efficiently due to ground effect. This is the whole reason for flying in ground effect. Otherwise we might as well build a real airplane and get up to cruising altitude. So when we look at the efficiency of a WIG aircraft, we see a trade off between increased lift efficiency with an increase in aerodynamic drag due to the low density altitude. Because of this, WIG aircraft generally fly at modest speeds.
The ekranoplane was built to replace ships. By flying in ground effect it goes faster and cannot be torpedoed. An airplane could do the same, but would need to be bigger for the same payload, and would burn more fuel. On the plus side, a conventional airplane would be faster.
Don't forget in addition to going faster and not cannot be torpedoed, a WIG craft cannot be boarded by pirates!!