On Apr 15, 2:15*pm, wrote:
On Apr 15, 12:08 pm, Le Chaud Lapin wrote:
* * * * Symmetry often means simple which in turn often means heavy.
Bridges are complex affairs to save weight so they don't collapse
under their own mass. The lightest and most useful airplanes are
usually rather complex structurally.

I do notice that many of them follow the basic model, even model
airplanes. Engine in front, long wings, long fuselage, little
empannage with controls, careful attention to balance, primarily due
to engine and other heavy components. I would probably break away
from this model.

3. Inexpensive USB-based COTS sensors everywhere.
4. Inexpensive USB-based COTS controls everywhere.
5. Elimination of conventional ICE and prop. [Biggest impediment to
flying car, in my not-sufficiently-educated opinion].

* * * * So, electric, which is really heavy and has short range, or a
turbine, which makes the money saved using COTS sensors look tiny
indeed. Or were you maybe thinking nuclear?

Right now, hybrid electric, but yes, the final part of drive system
would undoubtedly be electric.

6. Even weight distribution. Ideally, the aircraft would have a box-
like structure.

* * * * Drag, big time. Corners, even corners aligned with the flight
path, create drag. Even weight distrubution will mean CG problems, or
spin recovery issues.

Assuming the engine-mounted-foward model, etc. What does one call this
model anyway?

7. Glass-cockpit everything with marginal cost of $1000 for
commodity CPU. *No more* Garmin.
8. Pressurized cabin.

* * * * *Weight. Lots of weight. The systems to control it weigh more,
too. A fuselage strong enough for pressure is considerably heavier
than its non-pressurized counterpart.

Agreed.

9. Computer assisted take-off, computer assisted approach, computer-
assisted stabilization, computer-assisted tracking.

* * * *Might as well leave the pilot on the ground. Why bother
learning to fly? Besides, there are already too many people driving
airplanes that know too little about flying.

Who knows...it's 2008. I'm an engineer, and I like numbers,
caculations, etc. But frankly, I'd get more pleasure sometimes from
flying if I could just get in and go. Not all pilot's feel this way,
but many common people do. Might be time to start thinking about
accommodating them. It would expand GA considerably.

10. Ultralight components (no pun intended). I see no fundamental
reason that a 100kg man should ride in 1000kg vehicle. Use plastic and
other frilly components if doing so does not compromise structural
integrity or pilot safety.

* * * Already been done. Leeon Davis designed a single-seat airplane
that weighed 177 lb and was powered by an 18 HP Briggs industrial
engine. Clocked well over 100 mph.

Nice.

12. Abnormally-scary dependence on fly-by-wire. If it can me made
electronic instead of mechanical, make it so.

*What are you saying? Fly-by-wire is scary but we'll make it so
anyway?

I'm saying that the scary might not be as hairy as the wary claim it
to be. I have been in an uncountable number of situations where
experts in completely different fields were mutually intimidated/
suspicious of the the other's profession. They are confident in their
own, but the idea that the other might do his part right seems
somewhat absurd. Universities now have program where the actively
attempt to break down this mindset. Not sure how well it's working.
I think in case of fly-by-wire, yes, it is being done, but the way it
is being done is not the way a "conventional" software/electrical
engineer would do it. This is why incremental improvements are so
painful. Someone will take an existing 30-year-old actuator, decide
that it could be controlled electronically, leave in the 90% of the 30-
year-old component, and add 10% electronics, and charge a hefty
premium for the design over what a conventional electrical engineering
firm would charge, for various reasons. This is painful. A systemic
approach is necessary, IMO.

13. Basic safety features (parachute, auto-oxgen, auto-extinguisher,
auto-pilot when computer senses that pilot is incoherent)

* * * * * Parachutes weigh something and take up considerable room.
Oxygen tanks are heavy, too and take up more room. Where is the pilot
supposed to go in this little airplane? And what is he doing in it
when he's incoherent? And what happens if the computer incorrectly
decides he's incoherent and takes over just when the pilot, who sees a
danger approaching, decides to avoid that danger and the computer
decides NO?

Pilot override? All these are policy questions, not mechanism.

* * * *The Piper Arrow had an automatic gear-extension system to
prevent the pilot from landing gear-up. It sensed pitot pressure and
dropped the gear below a certain airspeed. Trouble was that this
"safety feature" killed a few folks when the pitot tube iced up and
the system thought airspeed had dropped, so it lowered the gear,
adding drag and another ice-catcher just when the pilot was struggling
to stay airborne long enough to get out of the ice. These automatic
systems sound nice until the unforeseen occurs. Those unforeseen
things are why it's harder to get a pilot's license than a driver's
license. You have to know what's going on.

Redundancy. And an emphasis on electronics.

Frankly, if someone approached me with a component that they claimed
to be "electronic", but was actually an old mechanical control that
was "enhanced" with an electronic actuator, I'd be extremely nervous.
I'd have multiple, redundant, advanced, inexpensive controls using
modern materials.

14. Convenient means of entry an exit. Grandma should not have to
mount the wing.

*Good luck. Structural nightmare. The Cessna Cardinal successfully
addressed this back in 1968, but the weight penalty was significant.

Just took a look at Wikipedia. That aircraft looks very much like a
Cessna single-prop plane.

The aircraft I have in mind would look nothing like that, so I wonder
if there would be added weight.

15. Efficiency - all that heat lost by ICE, plus 20% loss due to prop
twisting air, plus unnecessary weight from all those mechanical
components that could just as well be made of plastic actuators.

* * Fantasy. Like I said, find those new technologies. As far as
plastic goes, the Boeing 787 is mostly plastic but its control are
metal. Plastic does not do well handling hot hydraulic fluid.

I was thinking of plastic in cabin, for exmaple.

15. Leather seats.

* * *Weight.

Really?

16. Luxury sound system including digital radio.

*More weight. And a distraction. Stay at home in your living room.

17. Video-games (including Microsoft Flight Sim).

* * * * Now there's an intelligent thing. Flying while pretending to


18. Inter-aircraft communication using WiMax (or something similar).
Proximity detectors, etc.

* * * * Weight. Complexity. Expense.

My Dell laptop can provide these features. I bought it for $1000.
Bring it on board the airplane should not down it. It's mass is less
than 3kg.

19. Pre-heating and pre-cooling of cabin.

* * * * *With what? Heaters and air conditioners weigh a lot.
Especially air conditioners.

Heating coil and blower for heater. For AC, i'd have to do research.
The cabin, being for 1 person, would be tiny.

20. Three-liter water tank with spigot on dash.

* * * * *Another eight or nine pounds.

21. Air conditioner.

* * * See above.

22. Integration of all instruments into computer monitors with few
exceptions (backup compass, backup altimeter, backup etc.)

* Been done.


23. USB camera mounts around the aircraft
24. Electronic megaphone for voice communication to those in immediate
vicinity of aircraft.
25. Real-time capture of all flight data in minutest detail onto
sealed hard disk for when it crashes.
26. Elimination of rudder control with foot pedals. Computers should
make this unnecessary, right?

* * * Someone is lazy.

Yes indeed. My boss once told me that he likes to hire "lazy smart
people", because they'll find the most efficient way to get something
done to avoid working.

27. Significant reduction in sound pollution.

* Mufflers. More weight.

Assumes conventional ICE, etc. I do admit that I do not know what to
power electric system with, but under assumption that electric power
is available, there is something I am exploring that would be a lot
quieter than ICE-mounted prop configuration.

28. Rear-mounted fuel-tank.

* * * *So fuel splashes forward over everything when the airplane
ccrashes, and so that the CG wanders all over the place as fuel is
burned.

I thought about this. My Jeep Cherokee V8, and many SUV's have engine
mounted at slight angle so that, if you rear-end someone hard, the
engine will drop down and not come into the passenger area. Might go
with something similar for aircraft, so that, on crash, engine has
tendency to detach. The tank would have to be extremely sturdy
though, adding weight.

29. Trash bin.

* * * *The whole design should go into this trash bin.
Hah.

30. Order of magnitude more control over the orientation of
aerodynamic surfaces. [IMO, this represents and *enormous* opportunity
reduce requisite skill in flying aircraft].

* * * * * * OK. Design an "airplane" with all those goodies, and see
just how heavy it will be. It'll have a stall speed in the range of
120 MPH. *Even the 1000 kg airplane that carries the 100 kg man, the
airplane you think is inefficient, already exists and has some of the
above goodies. That's why it weighs so much and can carry so little.

I'm probably going to focus just on the propulsion system, since, if I
turn out to be wrong, there is no point in continuing with anything
else, as all improvements thenceforth would be necessarily tweakage of
the basic aircraft model: engine, prop, balancing, etc.

* * * * You forgot de-icing systems.

-Le Chaud Lapin-