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Propeller Efficiency



 
 
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  #21  
Old April 15th 08, 08:56 PM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Propeller Efficiency

On Apr 15, 2:33*pm, B A R R Y wrote:
On Tue, 15 Apr 2008 12:21:07 -0700 (PDT), Le Chaud Lapin

wrote:
On Apr 15, 1:21*pm, B A R R Y wrote:
Le Chaud Lapin wrote:


26. Elimination of rudder control with foot pedals. Computers should
make this unnecessary, right?


How does the computer know when you *want* to slip?


When you move the controls in such a way to indicate that you want
slipping.


If you flew, you'd know how silly that comeback is.


I have flown, though never slipped.

I received 3 responses to my imaginary-flying-car, and one thing they
all have in common is that they presume that the basic design of such
a vehicle would be, more or less, a Cessna, tweaked to add the
features I listed. As I mentioned before, I would not do that.

-Le Chuad Lapin-



  #22  
Old April 15th 08, 09:31 PM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Propeller Efficiency

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-
  #23  
Old April 15th 08, 10:11 PM posted to rec.aviation.piloting
Benjamin Dover
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Posts: 292
Default Propeller Efficiency

Le Chaud Lapin wrote in
:

On Apr 15, 2:33*pm, B A R R Y wrote:
On Tue, 15 Apr 2008 12:21:07 -0700 (PDT), Le Chaud Lapin

wrote:
On Apr 15, 1:21*pm, B A R R Y wrote:
Le Chaud Lapin wrote:


26. Elimination of rudder control with foot pedals. Computers
should make this unnecessary, right?


How does the computer know when you *want* to slip?


When you move the controls in such a way to indicate that you want
slipping.


If you flew, you'd know how silly that comeback is.


I have flown, though never slipped.

I received 3 responses to my imaginary-flying-car, and one thing they
all have in common is that they presume that the basic design of such
a vehicle would be, more or less, a Cessna, tweaked to add the
features I listed. As I mentioned before, I would not do that.

-Le Chuad Lapin-





The car you want was designed and built by Francisco Scaramanga many years
ago. He started with a car, specifically an AMC Matador, and modified it
so it could be flown as well as driven.

  #24  
Old April 15th 08, 10:47 PM posted to rec.aviation.piloting
[email protected]
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Posts: 316
Default Propeller Efficiency

On Apr




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 motor is angled to give better geometry to the drive train,ie the
U joints, constant velocity joints, rear end posiotion. The reason it
is obvious is that SUV's sit up higher and the angle is steeper. Even
cars have the motor tilited slightly.. Look close ol buddy........

Ben
  #25  
Old April 15th 08, 11:08 PM posted to rec.aviation.piloting
Le Chaud Lapin
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Posts: 291
Default Propeller Efficiency

On Apr 15, 4:50*pm, Nomen Nescio wrote:
-----BEGIN PGP SIGNED MESSAGE-----

From: Le Chaud Lapin

I'm an engineer


Most pilots can talk with someone. who claims to be a pilot. for 2 minutes
and know if they really are.
Most engineers can talk with someone. who claims to be an engineer. for 2 minutes
and know if they really are.

I'm both.
You're neither.


Thanks for afternoon laughs. )

-Le Chaud Lapin-
  #26  
Old April 15th 08, 11:45 PM posted to rec.aviation.piloting
B A R R Y
external usenet poster
 
Posts: 517
Default Propeller Efficiency

On Tue, 15 Apr 2008 12:56:21 -0700 (PDT), Le Chaud Lapin
wrote:


I have flown, though never slipped.


That's right, PC sims don't have crosswind. My mistake.
  #27  
Old April 16th 08, 12:02 AM posted to rec.aviation.piloting
Orval Fairbairn[_2_]
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Posts: 530
Default Propeller Efficiency

In article
,
Le Chaud Lapin wrote:

On Apr 15, 10:17*am, Tina wrote:
Not trying to *invalidate the point you're making, but sometimes we
simply get lazy or our brain goes asleep. I got some useful help here
after having asked what turned out to be something easily found had I
been better at searching.


That's actually what happened in my case.

However, trom a technical perspective *going from an 80% efficient
prop to 100% will most likely not do much to change a design from
fantasy to 'realizable'. *There's a hierarchy of problems associated
with design, and this particular one, prop efficiency, would be pretty
far down on most designers' *lists if they were looking to design an
innovative GA airplane that converts to a car.


A hieararchy indeed. One would have to solve many problems at once.
I'm already spending too much time thinking about this, but if I were
to have a go at it, right now, I would aim for:

1. One seat-only, initially.
2. Structural symmetry throughout, whenever feasible.
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].'


Replace the ICE with what???


6. Even weight distribution. Ideally, the aircraft would have a box-
like structure.
7. Glass-cockpit everything with marginal cost of $1000 for
commodity CPU. *No more* Garmin.
8. Pressurized cabin.


Why? Most light aircraft do not fly high enough to require
pressurization -- just an added expense/weight/complexity.


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


Again -- why? Anybody competent rnough to fly has to be competent enough
to navigate. Added expense/complexity.


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


Bad engineering! KISS = Keep It Simple, Stupid! Light aircraft are
designed for stability/controllability. Adding another system to enable
it degrades reliability and adds expense/complexity.

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



KISS!


14. Convenient means of entry an exit. Grandma should not have to
mount the wing.
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.
15. Leather seats.
16. Luxury sound system including digital radio.


Detracts from flying.

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


Absolutely NOT!


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


It is called a "radio."

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


KISS!

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


A simple water bottle suffices.


21. Air conditioner.


Nice, but KISS!


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


KISS!


23. USB camera mounts around the aircraft


KISS!


24. Electronic megaphone for voice communication to those in immediate
vicinity of aircraft.


KISS!


25. Real-time capture of all flight data in minutest detail onto
sealed hard disk for when it crashes.


KISS!

26. Elimination of rudder control with foot pedals. Computers should
make this unnecessary, right?


WRONG! Necessary for handling crosswind takeoffs/landings.


27. Significant reduction in sound pollution.


KISS!


28. Rear-mounted fuel-tank.


??????

29. Trash bin.


??????

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



??????




It would be nice to save 20% of one's fuel, though.


Sometimes those not skilled in the art make breakthroughs, most times
not. If you saw the potential cancer treatment talked about on 60
Minutes last weekend you were were treated to something that most
likely will fall into the "not" group.


What do you think of Steve Moller? I have seen respectable
commentators laud his work, but...


I think that he is a fraud and a scamster. His design contains numerous
errors and demonstrates a complete ignorance of aviation, aerodynamics,
controllability, engines and reliability.

--
Remove _'s from email address to talk to me.
  #28  
Old April 16th 08, 12:12 AM posted to rec.aviation.piloting
[email protected]
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Posts: 1,130
Default Propeller Efficiency

On Apr 15, 2:31 pm, Le Chaud Lapin wrote:

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


Tractor. If you are going to design an airplane you should be a LOT
farther along than that.

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.


So you can't tell the difference between a 172 and a 177. Take
a much closer look. Just because it has a high wing and the prop on
the nose doesn't mean it's the same design. It's an entirely different
airplane.

I was thinking of plastic in cabin, for exmaple.


Well, now. Maybe you should actually climb into a light
airplane and see what the interior is lined with. They beat you to it
back in the 1950s.

Dan
  #29  
Old April 16th 08, 12:49 AM posted to rec.aviation.piloting
Le Chaud Lapin
external usenet poster
 
Posts: 291
Default Propeller Efficiency

On Apr 15, 6:02*pm, Orval Fairbairn
wrote:
*Le Chaud Lapin wrote:
5. Elimination of conventional ICE and prop. [Biggest impediment to
flying car, in my not-sufficiently-educated opinion].'


Replace the ICE with what???


That's the part I am working on. Note that I don't necessary mean a
new type of egine. I mean the ICE/prop combination. If we could get
rid of this somehow, it would solve several problems at once.

An associate of mine and I were out not long ago flying a DA-20. It
actually overheated. I was thinking.. "Why is it that we are sitting
here on the ramp, waiting because our engine wasted energy? So we're
basically sitting here because it couldn't waste energy fast enough,
and now we're waiting for it to waste even more energy."

Why? Most light aircraft do not fly high enough to require
pressurization -- just an added expense/weight/complexity.


The computer system. It would allow the owner to be able to use
inexpensive COTS components (generic, $100, 1TB hard disks).

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


Again -- why? Anybody competent rnough to fly has to be competent enough
to navigate. Added expense/complexity.


Software is weightless, and the material cost is essentially zero, so
it would be a nice-to-have. Additionally, as mentioned, I would
increase the number of moveable airfoils on the aircraft dramatically,
each controlled by the computer.

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


Bad engineering! KISS = Keep It Simple, Stupid! Light aircraft are
designed for stability/controllability. Adding another system to enable
it degrades reliability and adds expense/complexity.


As I've mentioned several times, there would have to be a change in
how the pilot thinks about flying. Right now, the pilot is a very
active participant in seeking balance. Much of this could be done
automatically by computers, if the pilot uses the controls instead to
indicate desired results instead of steps toward that result.

And there are things that a computer can do that a pilot cannot do,
like auto-stabilization in present of noise (light turbulence) based
on sophisticated filters from estimation theory.

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


KISS!


14. Convenient means of entry an exit. Grandma should not have to
mount the wing.
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.
15. Leather seats.
16. Luxury sound system including digital radio.


Detracts from flying.


Why? On trek to Bahamas from Florida, certainly it would be more
pleasant to have a bit of entertainment. I would also use USB ports
for headsets, like the high-quality $30 USB model from Logitech I
bought not long ago.

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


Absolutely NOT!

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


It is called a "radio."

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


KISS!

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


A simple water bottle suffices.

21. Air conditioner.


Nice, but KISS!

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


KISS!

23. USB camera mounts around the aircraft


KISS!


Hmm...this "KISS" I cannot let go. These things are not just for
frills. They would actually make flying easier (and maybe safer).
Since we're on this subject, I have noticed that there is creepage/
hysteresis/hypocrisy in the aircraft gadget industry:

1. Someone proposes some gadget.
2. Pilots complain that it is too complicated, to dangerous, will
never work, unnecessary, etc.
3. Some aircraft company does it anyway.
4. Some periodical writes about it.
5. Pilot's "oooh...ahhh" about it.
6. Repeat, except topic changes to some other gadget.

I imagine that, 100 years from now, when aircraft contain most of the
things I have mentioned plus much more...

24. Electronic megaphone for voice communication to those in immediate
vicinity of aircraft.


KISS!


Not too hard to do.

25. Real-time capture of all flight data in minutest detail onto
sealed hard disk for when it crashes.


KISS!


Would be incremental step from fly-by-wire control anyway.

26. Elimination of rudder control with foot pedals. Computers should
make this unnecessary, right?


WRONG! *Necessary for handling crosswind takeoffs/landings.


27. Significant reduction in sound pollution.


KISS!


Sound reduction would be natural side-effect of propulsion system I
have in mind.

28. Rear-mounted fuel-tank.


Ahem..I should not have mentioned this. It turns out that, for my
propulsion system, this is optimal location of fuel tank, and it is
not because of balance.

29. Trash bin.


??????


To throw away hamburger wrapper.

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


??????


Four-wheel drive.

The situation we have now is that the aircraft all have a particular
shape. I don't know what this shape is called, be we all know what it
is. The pilot has to actively think about CG so that it balance is
achieve. The location of wings, extent of fuselage, etc, are not
arbitrary. Design choices made earlier heavily influence set of
choices later. The moment it is decided that a huge, ICE engine+prop
is to be mounted at front of plane, many other things follow
necessarily. The design I am thinking about (very early..don't even
know if it will work) does not have ICE+prop., and the pieces are much
lighter and can be distributed better. The aircraft would not need a
long fuselage, etc. But there would be many more control surfaces.
Naturally, the pilot isn't going to have 40 yokes in cockpit
controlling alll these surfaces, plus talking to ATC, plus eating,
plus playing Flight Sim...so i would use a computer to effect that
which s/he desires.

It would be nice to save 20% of one's fuel, though.


Sometimes those not skilled in the art make breakthroughs, most times
not. If you saw the potential cancer treatment talked about on 60
Minutes last weekend you were were treated to something that most
likely will fall into the "not" group.


What do you think of Steve Moller? I have seen respectable
commentators laud his work, but...


I think that he is a fraud and a scamster. His design contains numerous
errors and demonstrates a complete ignorance of aviation, aerodynamics,
controllability, engines and reliability.


He's been at it so long. When I first hear dabout him..how long ago he
started, it was discouraging. But after taking a look at the Skycar
and the steel cable suspending one of his prototypes (I think the
insurance excuse is just an excuse..)...made me start wondering
exactly what it is he wants. This whole flying car business seems
seductive. One can easily fall into the trap of wanting to be the
first to make a flying car, rather than wanting to know how to make a
flying car, to distinct philosophies, one potentially yielding fruit
with patience and tenacity, the other unforgivingly destructive.

-Le Chaud Lapin-
  #30  
Old April 16th 08, 12:56 AM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 1,130
Default Propeller Efficiency

On Apr 15, 5:49 pm, Le Chaud Lapin wrote:
On Apr 15, 6:02 pm, Orval Fairbairn
wrote:

Le Chaud Lapin wrote:
5. Elimination of conventional ICE and prop. [Biggest impediment to
flying car, in my not-sufficiently-educated opinion].'


Replace the ICE with what???


That's the part I am working on. Note that I don't necessary mean a
new type of egine. I mean the ICE/prop combination. If we could get
rid of this somehow, it would solve several problems at once.

An associate of mine and I were out not long ago flying a DA-20. It
actually overheated. I was thinking.. "Why is it that we are sitting
here on the ramp, waiting because our engine wasted energy? So we're
basically sitting here because it couldn't waste energy fast enough,
and now we're waiting for it to waste even more energy."

Why? Most light aircraft do not fly high enough to require
pressurization -- just an added expense/weight/complexity.


The computer system. It would allow the owner to be able to use
inexpensive COTS components (generic, $100, 1TB hard disks).

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


Again -- why? Anybody competent rnough to fly has to be competent enough
to navigate. Added expense/complexity.


Software is weightless, and the material cost is essentially zero, so
it would be a nice-to-have. Additionally, as mentioned, I would
increase the number of moveable airfoils on the aircraft dramatically,
each controlled by the computer.

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


Bad engineering! KISS = Keep It Simple, Stupid! Light aircraft are
designed for stability/controllability. Adding another system to enable
it degrades reliability and adds expense/complexity.


As I've mentioned several times, there would have to be a change in
how the pilot thinks about flying. Right now, the pilot is a very
active participant in seeking balance. Much of this could be done
automatically by computers, if the pilot uses the controls instead to
indicate desired results instead of steps toward that result.

And there are things that a computer can do that a pilot cannot do,
like auto-stabilization in present of noise (light turbulence) based
on sophisticated filters from estimation theory.

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


KISS!
14. Convenient means of entry an exit. Grandma should not have to
mount the wing.
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.
15. Leather seats.
16. Luxury sound system including digital radio.


Detracts from flying.


Why? On trek to Bahamas from Florida, certainly it would be more
pleasant to have a bit of entertainment. I would also use USB ports
for headsets, like the high-quality $30 USB model from Logitech I
bought not long ago.



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


Absolutely NOT!


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


It is called a "radio."


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


KISS!


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


A simple water bottle suffices.


21. Air conditioner.


Nice, but KISS!


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


KISS!


23. USB camera mounts around the aircraft


KISS!


Hmm...this "KISS" I cannot let go. These things are not just for
frills. They would actually make flying easier (and maybe safer).
Since we're on this subject, I have noticed that there is creepage/
hysteresis/hypocrisy in the aircraft gadget industry:

1. Someone proposes some gadget.
2. Pilots complain that it is too complicated, to dangerous, will
never work, unnecessary, etc.
3. Some aircraft company does it anyway.
4. Some periodical writes about it.
5. Pilot's "oooh...ahhh" about it.
6. Repeat, except topic changes to some other gadget.

I imagine that, 100 years from now, when aircraft contain most of the
things I have mentioned plus much more...

24. Electronic megaphone for voice communication to those in immediate
vicinity of aircraft.


KISS!


Not too hard to do.

25. Real-time capture of all flight data in minutest detail onto
sealed hard disk for when it crashes.


KISS!


Would be incremental step from fly-by-wire control anyway.

26. Elimination of rudder control with foot pedals. Computers should
make this unnecessary, right?


WRONG! Necessary for handling crosswind takeoffs/landings.
27. Significant reduction in sound pollution.


KISS!


Sound reduction would be natural side-effect of propulsion system I
have in mind.

28. Rear-mounted fuel-tank.


Ahem..I should not have mentioned this. It turns out that, for my
propulsion system, this is optimal location of fuel tank, and it is
not because of balance.

29. Trash bin.


??????


To throw away hamburger wrapper.

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


??????


Four-wheel drive.

The situation we have now is that the aircraft all have a particular
shape. I don't know what this shape is called, be we all know what it
is. The pilot has to actively think about CG so that it balance is
achieve. The location of wings, extent of fuselage, etc, are not
arbitrary. Design choices made earlier heavily influence set of
choices later. The moment it is decided that a huge, ICE engine+prop
is to be mounted at front of plane, many other things follow
necessarily. The design I am thinking about (very early..don't even
know if it will work) does not have ICE+prop., and the pieces are much
lighter and can be distributed better. The aircraft would not need a
long fuselage, etc. But there would be many more control surfaces.
Naturally, the pilot isn't going to have 40 yokes in cockpit
controlling alll these surfaces, plus talking to ATC, plus eating,
plus playing Flight Sim...so i would use a computer to effect that
which s/he desires.

It would be nice to save 20% of one's fuel, though.


Sometimes those not skilled in the art make breakthroughs, most times
not. If you saw the potential cancer treatment talked about on 60
Minutes last weekend you were were treated to something that most
likely will fall into the "not" group.


What do you think of Steve Moller? I have seen respectable
commentators laud his work, but...


I think that he is a fraud and a scamster. His design contains numerous
errors and demonstrates a complete ignorance of aviation, aerodynamics,
controllability, engines and reliability.


He's been at it so long. When I first hear dabout him..how long ago he
started, it was discouraging. But after taking a look at the Skycar
and the steel cable suspending one of his prototypes (I think the
insurance excuse is just an excuse..)...made me start wondering
exactly what it is he wants. This whole flying car business seems
seductive. One can easily fall into the trap of wanting to be the
first to make a flying car, rather than wanting to know how to make a
flying car, to distinct philosophies, one potentially yielding fruit
with patience and tenacity, the other unforgivingly destructive.

-Le Chaud Lapin-


Mx in disguise, for sure. The more you post, the more we realize
you don'y fly.

Dan
 




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