Neil,
Do
you have a wideband O2? I have to run in the low 11’s at
full power and under boost for takeoff. 7000 rpm / 30-48” MP
to keep egt’s around 1600F. Typical cruise between 4800 –
5200 rpm / <30 “ MP with F/A 15.8:1 brings EGT’s into
the 1500’s. With an intercooler I would expect F/A in the
12’s will keep egt’s below 1600 but that’s just a guess. I
have seen EGT’s at or below 1475F on cold days at altitude.
The only time I run stoichiometric is in the pattern and low
MP.
Information
from Pro Formula Mazda
Engine Vitals: Exhaust Gas Temperatures
Exhaust Gas Temperatures (EGTs) are the second most
important tuning and troubleshooting channel next to Lambda.
EGTs reflect on the injector balance between the front and
rear rotor Reflects misfires through high readings accompanied
by normal lambda Decline in engine performance can be
evidenced by the rate of temperature acceleration between the
rotors during a long pull – gapping Emphasis needs put on the
condition of the EGTs – low reading sensors are beginning to
fail. In order to have an accurate assessment of the
performance, EGT sensors must be replaced often. Generally,
one EGT sensor is used per rotor. One sensor bung should be
welded on the each the outer exhaust pipes 3” from the header
flange (the center pipe usually does not receive a sensor).
The sensor depth should be enough to where the tip of the
sensor is in the centerline of the exhaust flow. Operational
Range: Front Rotor: 1450F – 1600F, Rear Rotor: 1400F – 1550F
Engine Vitals: Lambda
Lambda is the measure of the amount of oxygen
in the exhaust stream. The value expressed is a percentage of
the stoichiometric air/fuel ratio 14.7:1.
Air/fuel ratio can be calculated by
multiplying the lambda value monitored by data system by 14.7
(ex: .90 Lambda translates as (.9 x 14.7 =
)13.23 Air/fuel ratio
Operating Range = .87 - .91, aim for .90
Bobby
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
Sent: Tuesday, December 04, 2018 1:30 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Hey Neil,
Ok, interesting stuff, but how do you keep the exhaust temp
below 1600 degrees without losing a lot of power? I no longer
have an EGT as it just worried me with 1800 degrees and the
cost of burnt off egt probes. From memory 1600 degrees goes
out the window at about 6000 rpm or less?
Neil.
Hi
Andrew, I know next to nothing about turbo technology so
have stayed clear of them; IIRC this is the first time
I’ve heard of using a turbo from the agricultural industry
and advice to stay clear of the automotive type ... seems
to make sense – tractors use turbos that last for decades.
Jeff
(13B, RD1-C, 144 hrs)
From:
Sent: December-03-18 5:14 AM
Subject: Re: [FlyRotary] Re: Hey Neil,
Neil, Type Turbo selection
Into search of flyrotary archives, you’ll get about 30
posts from 2002 to 13 that are worth reading, other
searches will give more.
Basically you want something the size
of a T04 60-1, keep the A/R >1, something like 1.15 or
1.30
T04’s are plentiful from all the older
diesels like 2wd tractors from last century. you probably
got a few parked up around you that will still be
servicable. If you can find one without a intercooler on
it, chances are that it might have the right compressor.
Otherwise they are easy to change.
Steer clear of automotive turbo’s, they
will overspeed at altitude & disintegrate, need waste
gates & blow off valves. Stuff thats not required on
an aeroplane.
When installing. Put a normally open
solonoid valve in the oil supply line. Allows you to close
the oil supply if the turbo blows its seal.
Always bugged me why turbo shops charge
so much for such a simple part.