>> This is a VERY simple system. No computer, no sensors, no
>> floats, no venturi, no fuel injectors, no nothing. Just very
>> low pressure fuel. The fuel orifice area simply increases with
>> the air passage area increase. Bigger fuel hole bigger air
>> hole. There is another simple series valve that controls leaning.
>> Paul Lamar
>>
>> Paul,
>> FWIW I believe the Aero-Carb violates the Lectron patents, if
>> they are still active. The Lectron I worked with used a square
>> slide like a slide throttle, but were built on a single bore
>> using a return spring and pull cable.
>> Bill Jepson
>>
>> http://www.aeroconversions.com/carb_specs.html
>>
>>
>> Times up.
>> Here it is. Super simple. A series of progressively larger
>> feed holes in the Teflon slide communicating a with a fixed
>> larger fuel hole in the aluminum spacer.
>>
>> Patent applied for :)
>> -- Paul Lamar ...No rotor no motor.
>>
>> Paul,
>> Sorry for not getting back yesterday, went to bed. The hole idea
>> is ok but you will have some problems. Kind of like a digital
>> drive for an analog circuit? An alternate idea would be to have a
>> single feed hole and a shallow tapered wedge connected to the
>> feed on the end. easier to make too. (some of the holes would be
>> reeeeeelly small) Tell me what you think.
>> Bill Jepson
>>
>> Good idea Bill. Cheaper than my system. Less cost to make.
>> Will work better. With an NC mill program you could vary the
>> slope of the ramp.
>>
>> Paul Lamar ...No rotor no motor.
>>
>> Here is the $7 mixture control valve from Home Depot.
>>
>> This is a major break through in aircraft fuel systems.
>> Simple systems like this work because the aircraft
>> engine has simple requirements. The load is fixed
>> and the RPM is constant. The only real reason for a complicated
>> carb or EFI system is automatic mixture control.
>> Since pilots are used to setting the mixture manually
>> it makes no sense to have an automatic mixture control
>> as well.
>>
>> With an EFI system you are in a world of hurt if your
>> alternator fails. You have a limited amount of time
>> before your EFI system stops as well as your engine.
>> That is due to the high current requirements of high
>> pressure fuel pumps. In this case you could use a hand
>> pump to keep fuel supplied to a small sump tank mounted
>> up under the cowl.
>>
>> The cost of this system everything included is less
>> than about $200. The cost of an EFI system everything
>> included is well over a $1000.
>>
>> Not to mention the intrinsic high power of a slide throttle
>> P-port engine.
>>
>> Klause Savier has run his O-200 with something similar as a back
>> up to a Posa Carb.
>>
>> BTW the Wright brothers used something similar.
>>
>> Paul Lamar ...No rotor no motor.
>
> I think it would be great as a redundant system (no offence). I
> can't see it
> running as efficiently as EFI but when it all goes to hell in a
> hand basket
> it sure would be nice and there is no real weight penalty to pay.
>
> John
>
> Why not as efficiently as EFI?
>
> Paul Lamar
Well perhaps with a flight engineer you might come close. Your
system will not be easy to adjust to the finite amount a computer
could. The HD $7 valves work great as on/off but I think you would
find it very difficult to adjust for economy cruise of say 9 gph or
if your fancy adjusting two valves to 4.5 gph (or X egt). A small
tap might be easier (especially if it is bumpy) or some sort of
needle valve. You might also have a time lag issue between your
adjustment and the engines reaction. You also have to fly the
airplane, with EFI your computer can check the fuel a hundred times
a second and it doesn't care if it is dark, bumpy or if some
controller is yacking at you.
I would see your system as being initially set to a happy medium
mixture setting and then shut off except for testing and for when it
get very quiet. Then you just crack open the shut off valve and sit
back and say a little prayer of thanks to PL.
I also don't know that the power failure
mode or EFI failure is that common. I see the merit in your proposal
and as a redundant system it is one with with very little failure
mode and very little additional weight. Your most likely failure
mode would be the additional in cowl fuel connections and I would
guess that connectors are probably more failure prone than the EFI.
I might be biased here as I have had 9 incidents that have had me do
precautionary landings, and only one that was a forced landing and
that was a fuel fitting coming off just after T/O. Luckily it came
of then, ten seconds later and I would have had to change my name to
Bob if I had survived (I hate cold water).
John
Ever fly a carb aircraft piston engine? Lots of mixture
adjustments are required. Most of the pilots successfully flying
them are not flight engineers.
The high quality ball valve shown has a one inch circumferential
travel. If you lengthened the lever to 3 inches, which
is a stock mixture control cable travel, fine adjustments are
possible. Mixture controls have vernier adjustments.
We have had several problems with EFI systems. There is a lot more
to fail. We had one total electrical failure crash that would not
have happened if they had a carb and mag. We had another in flight
fire that burned the wires going to the electrical fuel injectors
causing the engine to quit. Fortunately the guy was on short final.
I had a boost pump fail in a Mooney and the injection engine quit
with a bang. Parts of the vanes made it to the mechanical pump and
caused it to fail. Fortunately I was over an airport and got it back
on the ground dead stick.
AN fuel plumbing is very reliable.
Dual alternators and batteries are heavy and costly.
My guess is the most reliable aircraft engine is the simplest and
equipped with carbs and magnetos not counting turbines. They are
also easy to maintain, inspect and fix by non computer gurus.
Paul Lamar ...No rotor no motor.
This carb is impressive IMHO. But is it not the case that modern Jet
& Gas turbine engines have digital control with system redundancy
factored in - ?
Who else on here has had the frighteners with mechanical fuel
injection ?
Fly & Build Good - Bryan
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