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Donnknow about the Ellison not having a regulator. The device on the fuel
receiving end sure looks like a regulator with it's input in the upstream throat
of the unit. Perhaps it is something different.
Below is a reprint from Ellison's catalog.
The problem that Ed's friend had seems to fit into this explanation
perfectly.
Now to the design of the Ellison. It is basically a sophisticated posa type
carb in that as the throat of the unit is opened, it uncovers a series of holes
on a tube, which increase in number (possibly diameter-- haven't seen one in a
long time--. The tube with the holes can rotate 90* to change the mixtue-- if
pointed into the airstream of the throat you get idle cutoff, perpendicular get
full rich and anywhere in between varying mixture.The problem that I had with
mine-- years ago was thatasd the body is opened, the airflow across the tube
gets more fuel vapor and raw fuel from the side that has more holes and thus the
mixture of air/fuel vapor and raw fuel is not consistent over the length of the
tube. The side that has few holes is very lean and the side with most holes is
rich.
In an ideal world, as the mixture progresses through the manifold it
homoginizes, however, I found that not to be the case. With the twists and turns
of the manifold, the mixture was quite different cylinder to cylinder (what are
those).
Ellison suggested an oil heated manifold (which had no effect). I ended up
getting rid of it and going to multipoint injection. Granted this was on a VW
type engine. but the concept holds.
With the aforementioned posa (Much more of a similar problem as all of the
fuel was "dripped" from the same place with a conical needle creating the
increase/decrease) people were using a "swirl plate" in the induction system to
get a better mixing of the fuel/air.
FROM ELLISON WEB SITE...................
Gravity feed may be used with many high wing installations and some
installations which have a fuselage tank. The fuel pressure requirements of each
unit are as follows:
| Model |
Min (PSI) |
Max (PSI) |
| EFS-2 |
2 |
6 |
| EFS-3A |
0.5 |
6 |
| EFS-4 |
2 |
6 |
| EFS-4-5 |
2 |
6 |
| EFS-5 |
2 |
6 |
| EFS-10 |
12 |
15 |
Gravity feed will provide about 1.0 PSI for every 30 inches of head. For
example: The installation of an EFS-2 requires that the bottom of the tank must
be at least 60 inches vertical distance (plus the head loss of the valves,
fittings, lines and filters) above the Throttle Body to provide the minimum
required pressure. Remember that this height must be measured in the steepest
climb attitude for aircraft with engines in front, and in the steepest decent
attitude for aircraft with pusher engines. In this worst case attitude,
the fuel system should be flow tested with fuel flowing through the TBI fuel
inlet finger screen, and demonstrate a flow rate 150% of the fuel flow required
by the engine at it's maximum power output, when operating on the last gallon in
the fuel tank.
A common installation error made by our customers who wish to install the
Throttle Body, but don't want to install a fuel pump, is to try to design a
gravity feed fuel system where only minimum head in available. This is a
dangerous situation because the Throttle Body will meter fuel adequately at low
power settings with fuel pressure well below the specified minimum, but at high
power settings the Throttle Body is unable to meter sufficient fuel. As a
result, the engine will run lean at full throttle.
It is common aircraft practice to design a fuel system which has both an
engine driven pump and a backup pump such as an electrical boost pump, or
mechanical wobble pump. Systems which rely completely on electrical pumps
without any backup system should be avoided.
An excellent article about fuel system design by Lyle Powell
may be accessed by clicking on Fuel Systems
for Homebuilts.
In a message dated 2/26/2013 1:10:33 P.M. Central Standard Time,
res12@fairpoint.net writes:
I am aware of some of the problems with the Elison TB. As far as I know,
Elison did not use a pressure regulator, which is what Rotec added. They also
realized the mixture range problem, and added the reference pressure probe to
the pressure regulator. That is what I am now at, finding the best location to
pick up this reference pressure.
Richard
Sohn
N2071U
http://www.fairpoint.net/~res12/home.html
Sent: Tuesday, February 26, 2013 12:04 PM
Subject: [FlyRotary] Re: O2 Sensor data, Steve
B.
Richard, regarding the Ellison TB
I have a friend who tried an Ellison on his rotary -
never could get the low end and high end to work together. It appeared
that (at least for the size Ellison he was using) that the range of airflow
quantity below idle and WOT was outside the range of the size Ellison he was
using. If he got the idle set right, he ran out of fuel on the top
end. If he got the top end running right, the idle was too
rich.
His engine eventually quit in flight, airframe was
destroyed - he fortunately escaped injury. Just thought I would pass it
on for what its worth.
Most O2 heater voltages are 12 -13 Volts - but, not
certain about the Renesis O2.
Sensor output for narrow band is generally from 0
-1 volt, Wide band from 0 -5 volts.
Ed
Sent: Tuesday, February 26, 2013 12:27 PM
Subject: [FlyRotary] Re: O2 Sensor data, Steve
B.
I am planing to use an O2 sensor from a 2009 Renesis on my test engine.
Does anyone know what the heater supply is? I am measureing 2.4Ohm, cold.
Probably 5V? The connection is coming out of the ECU.
Would appreciate any info on that.
Still having issues with the mixture setting on the Rotec TBI (Ellison).
No real flying yet, just a lot of crow-hopping down the runway.
Richard
Sohn
N2071U
http://www.fairpoint.net/~res12/home.html
Sent: Tuesday, February 26, 2013 8:32 AM
Subject: [FlyRotary] Re: O2 Sensor data, Steve
B.
Forgot to
say, under diog. for RX8 they call both sensors HO2 not AF. ???
David.
From: hoursaway1@comcast.net To: "Rotary motors in aircraft"
<flyrotary@lancaironline.net> Sent: Tuesday, February 26, 2013
9:29:12 AM Subject: [FlyRotary] O2 Sensor data, Steve
B.
Steve,
another update on O2 sensor data,,, for a 2007 RX8 frnt. HO2 sensor is read in
mil. Amps,,, 1.0 mil. amp is center point under accell is looking for
decrease, under deccell looking for increase, did not give
min.-max. for the high & low that I think could have been useful.
David.
From: "Steven W. Boese" <SBoese@uwyo.edu> To: "Rotary
motors in aircraft" <flyrotary@lancaironline.net> Sent:
Monday, February 11, 2013 9:50:49 PM Subject: [FlyRotary] Re:
Crickets & progress
David,
Do you remember ballpark values for the amps and volts?
Thanks,
Steve
From: Rotary motors in aircraft
[flyrotary@lancaironline.net] on behalf of hoursaway1@comcast.net
[hoursaway1@comcast.net]
Sent: Monday, February 11, 2013 7:19
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re:
Crickets & progress
Steve, I'm
not sure why but when diog. the other day on 07 Mazda 3 for a code
P2188, Snap-on scanner shows me amps for pre cat. AF sensor & volts
for post cat. O2 sensor & that is how they describe them in Mitchel
Automotive diog. text. Hope this helps in some way. David R.
Cook RV6A
Rotary.
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