Your fancy schmancy dream machine

(Corrie) wrote in message . com...
Problem is, there's already a category for inline twin. Cessna beat
you to the punch. (Actually, Dornier beat Cessna, but the FAA didn't
type-certify the Do-335.) I wish you well in convincing the Feds that
an inline twin should be type-certified as a single.

I guess we'd have to pull the 337 and its variants into that same
"like a single" catagory unless you want to impose some restriction
such as not requiring engine 1/2 fuel management to make it simpler
for the guy with already too much to keep track of.

If your car brake system didn't have 2 parallel and independant
circuits you'd have more regular service required, but since its a
cross coupled redundant system, you can get away with all sorts of
abuse and neglect and still hardely ever have a total brake failure.
Its the same idea here with the in-line twin, since you have a fail
soft condition, you can afford to spend less money inspecting and
reinspecting your known working system.

The way in which the system is arranged has everything to do with its
composit reliability.

The comparison to Christmas lights oversimplifies things. We're
talking engines, not light bulbs. Lots of moving parts, hoses,
clamps, wires, etc. Two engines means twice the number of things that
can go kablooey, no matter where they are on the airplane.

I was making an over the top analogy to illustrate my point. What did
ya think of the car brake system analogy though? Brakes are pretty
important in a car, only dual redundant, and everybody ignores them
until they make noise or the car "pulls to the right" (Like when one
hydraulic circuit fails).

By the "string of lights" argument, the B-36 Peacemaker should have
been easier to maintain than a Fly Baby. Six recip engines, four jets
- LOTS of redundancy there! And yes, you could lose several engines
and still complete the mission. (While the public catch-phrase was,
"six turning and four burning", the crews were more familiar with,
"two burning, two turning, two smoking, and two joking.")

Thats a funny saying. Are the 2 joking part of the crew?

Thats overboard redundancy, and they didn't have 2 engines big enough
to do the job. 2 is kind of the magic number in that buisness. I've
seen 4 in my work on the Spirit. 3 dissimilar systems voting in
flight controls for commercial jets. The mission that needs to be
completed in our case is making it back to a real runway to get a
repair.

Redundancy has a price - the airplane spent 90 hours in maintenance
for each hour of flight.

Ya, I guess there is a real price required to haul tons of bombs
thousands of miles. Good thing thats nothing like what we're trying
to do here.

Redundant, fail-safe (or gracefully degrading) systems increase
confidence, yes. But it's a BAD idea to encourage complacency.
"Neglect not thy maintenance, lest the ground rise up and smite thee."

Its also a bad idea to discourage people from participating in sport
aviation because its dangerious or too costly. How many people can
afford to fly as much as they'd like to? Instead, many fly just
enough hours to keep current.

Yes, the laws of physics mean that for a given weight and stall speed,
there's a limit to the top speed. I expect you could build a
lightweight 40-to-400kt. variable-geometry wing out of carbon fiber,
but who could afford it?

So what you're saying is that its not practical with the state of the
art to build a 40-to400kt plane with the other sport limitations, so
why the law then?

But I suspect there's another reason for the speed limitation, though
I hesitate to bring it up. The Sport classification seems to be aimed
at, erm, uh, ok, I'll say it - dilletantes. Folks who want to fly,
but who don't want to (or can't afford to) spend a whole lot of time
and money doing it.

That would seem to be an admirable goal if it can be done relatively
safely. (Relative to driving a car to the airport)

A low-performance pilot in a high-performance
airplane is an accident looking for a crash site. The speed limit may
simply be an attempt to save lives.

Its a misguided attempt that restricts innovation. A plane that can
fly 150kts in a straight line but still land at 40kts isn't all that
much more dangerous. You might argue that having a wider speed
evelope is actually safer for the pilot.