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I built my own thermocouples for my EGT's and they are still in great shape after a 100 hours. There are 2 of them less than an inch from each exhaust port and another a few inches further at the turbine inlet. A fourth one is about 24" downstream of the turbo. I regularly expose them to 950C (1750F). I recently removed them for inspection and only one needed a light tap to free it up for removal, so they don't jam up and get stuck or melt and bend. They don't show any signs of wear. They were easy to make and long ago I wrote up a full description on how to do it. Unfortunately I didn't include pictures but the description is quite thorough. I was fortunate to have all the materials on hand so it didn't cost me anything, but I can't imagine the supplies would cost that much then you could make as many as you need for cheap, and likely not have to replace them again. It is own my google drive and can be viewed here
Andrew,
yeah, my probes were only 2 inches from the port
and melted quite nicely. All with the microtech ECU which was a
fair "illegitimate" to tune. I tend to suspect that the min dist
should be 4 inches or more. That turbo you suggest -- it was
fitted to nearly all IH machinery, even the old 1480! Does that
go back! Do you have any idea as to its weight? Neil.
Neil. others will know lots more than me as I'm still
trying to work this engine out.
I don't really have enough data to quote reliable
numbers, But last flight the data recorder showed egt
850-950c upto 1030c all at same rpm's 2200-2300 prop rpm
(2.85:1 reduction), seems the egt's are more a factor of
Afr's than rpm with the cooler temps when afr <12.5,
mid range when afr > 16, high temps afr between 13-16:1
Have now lost 3 egt sensors, originally all placed 50mm
from port. just too close me thinks. next lot will be
further away but this will place them in the tube where
gas from both rotors are mixed so not sure if I'll get
individual rotor temps or if that really matters anyway.
Andrew
Andrew, Just what EGTs do you see at what revs? Neil.
Neil, In Aus I’ve found
Justraceparts.com in Qld good for quality sensors,
their Egt sensors are $26 rated to 1300c. Have not
tried their instrument display though as I just
connect to my Efis & Em2.
Andrew
Who
was it on the list that was using a Maximite for
instrumentation? Shouldn't be too difficult to
add a temperature reference & order Chinese
probes from ebay.
Charlie
Bobby,
Only reason for an
addition to the fueltech is neatness, but at
that cost a stand alone EGT is
attractive.Currently investigating as
freight is the killer from the USA. Need a
local supplier,
Neil.
Neil,
I
have flown an Eaton MP90 4th
gen super charger for a little over
500 hours. No intercooler with the
super charger. Turbo FWF is in the
works and will have an intercooler. I
needed a wider compressor map at a
lower PR for takeoff than the TO4-50 .
I ended up purchasing a Garret GT3076R
w/ Tial 1.06 SS housing. I would have
preferred a journal bearing turbo but
this one is ball bearing.
Do
you have a reason for added EGT’s to
the fueltech vs an aircraft engine
monitor / efis?
Bobby
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Saturday, December
08, 2018 2:47 AM
To: Rotary motors in
aircraft
Subject: [FlyRotary] Re:
Hey Neil,
Bobby,
Yes I have the wide
band 02, but when I used the microtech
which was the reason I ditched it it was
to me impossible to tune properly. Then
Microtech refused to answer phone calls
or were gone to a drag race somewhere---
all queries were to be done by
internet. With microtech as I said
before the mixture knob did nothing
except occupy another hole in the dash.
EGTs in excess of 1850 degrees were
easily reached.
Long story short I left Microtech and
bought the fueltech. Much easier to
tune and actually have backup as
required. Did not add an EGT as nothing
seemed to change with the microtech, so
simply slept better not knowing what the
EGT's actually were.
Can add EGT to the fueltech but another
$1000 AUD. May have to go that way as
intend to get to 8000 RPM if required
Today at low 30's degrees my water was
on the thermostat at 95 degrees C and
oil around 90. Saw your temps and had a
heart attack until I realised you are
farenheit.
What turbo do you run and have you an
intercooler?
Will get to check out the ag turbos
shortly as there are hundreds of them
around here. Will get to weigh one
shortly.
Neil.
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.
--
Homepage: http://www.flyrotary.com/
Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
--
Regards Andrew Martin
Martin Ag
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