Good data. Thank you. Darryl Drummond used to build every one of the Star
Mazda engines.
Note that 1600 degrees is the maximum used in racing. The stock Iron based
seals may over heat and bow out in the center. They will not return to flat once
overheated. Note also that the rear rotor is run at lower EGT. It is cooled by
water already heated by the front rotor.
If you have no EGT gages you are dancing on the pond without knowing how
thick the ice is.
You want to know how effective the combustion process is, and EGT is the
best way to do that.
Timing can change EGT with no changes in mixture. You want peak cylinder
pressure at about 50 degrees ATDC. So the timing changing with RPM would be
ideal. So, late timing may allow mixture still burning to arrive at the EGT
probe. This is not an accurate look at combustion temperatures. So if you see
high EGTs reduce the timing
for a second or so and see if the EGT goes up. Then bump it up a few
degrees and see if it goes down. Simple.
For take off and climb enough timing and mixtures in the 12s, EGTs in the
16s or lower. Once at cruise altitude you can lean quickly through best
power to lean of peak EGT. Best power is too lean and produces the damaged
seals, and a better chance to detonate the engine. So you stay rich of best
power or lean of best power. Once at a stable speed and lean of peak EGT, you
can try adding some more timing, because lean mixtures burn more slowly.
For every RPM and mixture, there is an ideal advance setting. Find it by
watching the tachometer. This changes each day with OAT and barometric. Tuning
errors while lean of peak will not damage the engine. Tuning errors while rich
of peak may damage the engine.
Lean of peak means less fuel being burned.Less power being produced. Lower
coolant and oil temperatures, and lower top speed.
The less fuel being burned is the feature you are looking for.
Think like the engine......be the engine.......................
Perhaps Tracy or Mr.Leonard could publish their procedures?
Lynn E. Hanover
In a message dated 12/10/2013 8:26:01 P.M. Eastern Standard Time,
bhughes@qnsi.net writes:
Neil
This link has really good operating targets for our engine. They measure
EGT at 3 inches.
Bobby
MT electric three blade. I don't know what my peak EGT is at high
power but it should occur at 14.7 F/A. I would be surprised if it was much
over 1700F.
Bobby
Sent from my iPad
Bobby,
Do you know your prop size?? Neil.
Sent: Wednesday, December 11, 2013 11:23 AM
Subject: [FlyRotary] Re: 2 cycle premix
Neil
My EGT is usually around 1660 at 38", 7100 rpm, 12.5 F/A. I
have seen one rotor go to 1700 with an injector imbalance too rich. One
other time with a fouled plug. I think fuel was burning in the exhaust
manifold.
.80 oz per gallon.
Bobby Hughes
Renesis
Sent from my iPad
All,
finally
flying again, but my prop is too big. It is a 70” dia by 90 inch
pitch. Max revs on takeoff is about 6800 and the EGT is pushing
over the 1850 degrees. Obviously the prop is too big as revs are
restricted and the motor is working too hard hence the EGT. What
size props are you people running?? 2 rotor renesis.
Neil.
Sent: Thursday, August 08, 2013 7:12 AM
Subject: [FlyRotary] Re: 2 cycle premix
I use the same mix, but at closer to 1 oz/gal. Why?
That is what Tracy does. Dont think it is very critical over the
short term. I have gone without oil for a tank or two when I
didn't plan well. I have also put multi-weight aviation engine oil
in (at .5 oz/gal) on one occasion when I forgot to bring along any
2-stroke oil at all.
Dave Leonard
On Fri, Jul 26, 2013 at 11:39 AM, Bill Bradburry
<bbradburry@bellsouth.net> wrote:
I use the
same mix as Dennis but at the rate of 3/4 oz/gal in non-ethanol auto
gas. My engine is a Renesis with 70 flight
hours.
Bill
B
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of
Clouduster
Sent: Friday, July 26, 2013 9:17
AM
To: Rotary motors in
aircraft
Subject: [FlyRotary] Re: 2 cycle
premix
I use a 50 - 50 mix of MM and WalMart 2 stroke
@ 0.50 oz/ gal. Mixed in auto gas. My engine is a Renesis with
500 +hrs.
Dennis H.
Sent from my
iPad
For those of you who are
actually flying and have some time on your rotaries and are using
Pre-mix 2 cycle oil:
1) what oil are
you using
3) what
ratios are you using
4
where is the best place to get
it
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.nethttp://RotaryRoster.net