> Paul,
>
>
> I've been looking through the Kinsler catalog and they have
everything
> you need to put together a dead simple, reliable mechanical fuel
> injection system for not much money -- maybe less than an Ellison
carb.
>
> Constant flow fuel injection is used on aircraft piston engines
and
> works just like it sounds -- there is a constant spray of fuel
coming
> out of the injector nozzles, unlike the timed EFI and some
mechanical
> systems for cars.
>
> Constant flow is not great for cars, but perfect for airplanes,
because
> you are running at steady-state rpm and power most of the time.
>
> Have a look at the attached Kinsler Fuel Flow Diagram. The system
works
> like this: a mechanical fuel pump driven off the engine supplies
more
> fuel as rpm increases. It sends the fuel to a barrel valve that
> distributes the fuel to the individual nozzles at the intake
ports.
>
> The barrel valve is kind of like a spider in aircraft FI systems,
but it
> is directly linked to the throttle, so as the throttle is opened,
the
> barrel valve is opened as well, allowing more fuel to flow to the
ports.
>
> Fuel metering is accomplished upstream of the barrel valve by
putting a
> restrictor jet in a return line that goes back to the tank. So
the fuel
> coming from the pump has two places to go, the barrel valve that
leads
> to the engine nozzles -- and the restrictor jet. The more fuel
that
> flows through the restrictor jet, the less fuel goes to the
engine.
> Leaning is accomplished by varying the size of the restrictor jet.
A
> bigger jet means a leaner mixture because it allows more fuel to
circle
> back to the fuel tank and less to the nozzles.
>
> Kinsler has a cockpit adjustable mixture control that lets you
dial
> different jet sizes, as shown in the attached pictures. However,
the
> same thing could be accomplished with a simple ball valve, like
the Home
> Depot valve that Paul is implementing. It would be controlled by a
> Vernier control cable. This way no fuel has to go through the
cockpit.
>
> The barrel valve is available with a minimum of four ports, so
you can
> either put two nozzles on each P-port runner, one on each
four-runner
> manifold, or block off two of the ports and use one nozzle on each
> P-port runner. I would use two nozzles per runner to get better
> atomization. Also the fuel flow from two nozzles should be about
right
> for a single rotor. Same thing with the fuel flow of the 4-port
barrel
> valve.
>
> You could use Paul's slide throttle with this system or you could
use
> Kinsler throttle bodies which already have the bosses for
attaching the
> nozzles. If you roll your own you have to weld up some nozzle
bosses
> onto the runners. Btw, the Kinsler bosses can accept both the
> constant-flow and EFI injectors.
>
> This system can be used with a turbocharger or supercharger
because you
> can run it with high pressure. You could get significant
evaporative
> cooling effect by placing the nozzles close to the engine and
spraying
> the fuel right at the rotor. I would guess that you could
probably run
> 10 psi of boost without having to go to an intercooler.
>
> In a normally aspirated engine you can run it at lower pressure.
It also
> doesn't need heat, since icing is not possible. It provides all
the
> advantages of fuel injection in terms of precise metering and
mixture
> distribution.
>
> This should make for a very dependable, completely mechanical
system
> that is not dependent on electrical, control boxes or computers.
If you
> implement the flywheel magneto as well, you will have a real
aircraft
> engine.
>
> You can download the Kinsler tech catalog here:
>
> http://www.kinsler.com/catalog.htm
>
>
> Regards,
>
> Gordon.
>
Gordon
Very interesting. Good going.
One minor point though.
Please be advised that a ball valve is good as a shut off valve but
makes a
terrible leaning valve. For example the flow curve is like a J
curve. It's
design merit is in the low flow resistance when all the way open and
the
ability to shut the flow off quickly. A good use would be the
emergency shut
off valve. For metering you need a metering valve or commonly called
a
needle valve. The needle come down perpendicular to the flow and into
a
tapered valve seat. Excellent fine adjustment for gas or liquid
flows.
I have lots of experience using both of these valves with corrosive
gas and
liquid flows.
Doug Fir
Have you used them with a vernier leaning cable?
No problem. Just get a control cable you can twist
to adjust the needle valve. Do you have any
brands you can recommend or do we have to make one?
Paul Lamar ...No rotor no motor.
Doug,
Thanks for the scoop on the ball valve. Right after I posted this I
started thinking about the ball valve and began to suspect that it
might not be very good for leaning. A great shut off valve though.
A needle valve sounds like just the ticket -- hopefully there are
off-the-shelf items that will fit the bill. If not, you can always
use the Kinsler jet selector. Not as precise because it is stepped
rather than infitely variable, but still will work.
Regards,
Gordon.
I think the ball valve is not any more nonlinear than the round hole
in the slide throttle. One may get the impression it is hard
to adjust because the lever only moves 90 degree from full
on to full off while a threaded needle valve takes many turns
from full on to full off. The vernier push pull leaning cable to the
rescue. What the vernier does is allow super fine adjustments
by turning the knob. Much like a needle valve. I know some
of you have flown airplanes without vernier mixture knobs. Once
you have used one you will understand how well they work to
adjust the mixture to a fair the well.
IMHO the answer is lengthen the lever arm on the ball valve
until it travels 3 inch's on the end for a 90 degree
angular change. A lever about 2 inches long should do the
job.
However I am still open to using a needle valve if
somebody can come up with a practical design supplying a
3D drawing of same. A 2D sketch will suffice. If it looks
good and looks like it will work I will do a 3D.
------------------------------------------
OK I had an idea. We can make this out of aluminum tubing.
Three inch long needle. The valve seat is pressed in from
one end and the intake and outlet fittings are welded
or bonded on with JB Weld. Make two. One for each rotor.
The only draw back is the leaning knob works backwards.
push for shut off. Pull to richen and push to lean.
Paul Lamar ...No rotor no motor.
Cut threads on the cable attach end of the needle. Install a stop nut on
the threaded needle. Fabricate a small right angle arm (3/8x3/8x 3/4 or
whatever). Drill and tap a hole to match the threaded needle. Toward the
other end drill a hole to accept the ball of a Ball Joint assembly (ACS PN
05-07500). Thread the fabricated aluminum block onto the threaded needle
valve, thread a second stop nut onto the needle. Install a cable
grip/attachment near the end of the mixture tube where the inlet/outlet is.
Run the mixture control cable parallel to the needle valve assembly and
attach the ball joint assembly to the aluminum block.
PUSH now becomes OPEN, PULL now becomes CLOSED.
Since a picture is worth a thousand words - examine the AeroCarb to see that
this is how they actuate the throttle slide. The cable for the throttle
attaches right at the air inlet with a set screw clamp and runs parallel
with the slide throttle. A push on the cable pushes the throttle plate
open.
Terry Adams
Thorp T18C
Dragonfly MKI
The problem with that is it puts a bending load on
the needle. Might work but inelegant :)
Makes me a bit uncomfortable. Depends too much
on the friction of the seals.
Paul Lamar ...No rotor no motor.
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