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05-23-2015, 05:46 PM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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I've been looking at the intake/sump on my IO-540-D4A5 for the Rocket with a critical eye. From a design standpoint it's a mess, and there seems little hope of feeding 6 cylinders an equal slug of air. I like the tuned tulip induction tubes on the angle valve engines so I have purchased a few of these sumps for experimentation. I intend to install one on my engine and play with runner length to move the torque curve around to better align with my typical cruise profile (altitude and RPM).
I thought I was pretty clever installing a tuned angle valve sump on my parallel engine until I discovered that Robinson helicopters do exactly that. Interestingly, this hybrid engine retains the same 260 HP of the "straight" parallel sump.
Short of a CNC porting and flow balancing the heads, I'd think the use of a Lycoming "tuned" sump would be the most effective method of getting all six cylinders fed the same amount of air.
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Michael Robinson
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Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Last edited by Toobuilder : 05-24-2015 at 09:41 AM.
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05-23-2015, 07:14 PM
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Join Date: Dec 2012
Location: Brooksville, MS
Posts: 745
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Quote:
Originally Posted by Toobuilder
I intend to install one on my engine and play with runner length to move the torque curve around to better align with my typical cruise profile (altitude and RPM).
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Keep us informed!!! i would be interested in some data on this
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Weasel
RV-4 715hr Sold 
RV-10 "School Bus" -   +1600hr counting
Fisher Classic Cassler Power VW sold
RV-10 N7631T 820hr Sold
RV-8 700+hrs
Carbon Cub 200 hr Sold
One-Off Super Cub 100 hr
SERFI AWARDS
http://weaselrv10.blogspot.com/
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05-23-2015, 07:54 PM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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You bet. Success or failure, it will be documented here.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Michael Robinson
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Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
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05-23-2015, 11:54 PM
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Join Date: Apr 2014
Location: Wichita, KS
Posts: 8
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EFII GAMI Spread
I'll post more of my thoughts and experiences with the EFII system after I've had a better chance to tweak everything and then get some substantial time behind it. But for now, since folks are obviously interested and I have it handy, here are some data from a low-power flight a couple of weeks ago.
8000'
20.5"
2200 rpm
EGT 4 peaked at 9.5
EGT 2 peaked at 9.1
EGT 6 peaked at 9.0
EGT 1, 3, & 5 peaked at 8.5
GAMI spread 1.0 gal
EGT 4 peaked at 1288 deg and was at 1245 when the last EGTs peaked (43 deg LOP)
My AFR sensor showed between 16.0 and 18.0 from first to last peak, respectively (though since I created the sensor definition, I can't vouch for its absolute accuracy--it seems high).
When the last cylinders peaked (at 8.5 gph) I was doing 154 KTAS.
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Chris G.
RV-10 w/EFII
Wichita, KS
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05-24-2015, 06:29 AM
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Join Date: May 2005
Location: X35 - Ocala, FL
Posts: 3,679
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Chris, what was your percent power reading at that setting? I'm guessi about 45-50. That's amazing economy.
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Jesse Saint
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05-24-2015, 07:49 AM
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Join Date: Apr 2014
Location: Wichita, KS
Posts: 8
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Dynon was showing 47-50%, I believe. Skyview's lean function was showing GAMI spreads between 0.8 and 1.1 at those low power settings.
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Chris G.
RV-10 w/EFII
Wichita, KS
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05-24-2015, 08:39 AM
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Join Date: Oct 2005
Location: 08A
Posts: 9,500
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Quote:
Originally Posted by cmgolden
..here are some data from a low-power flight...
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Thank you Chris. Could you (or Jesse) tell us which engine model and intake manifold system is installed on this airplane?
Jesse, was the 1.4 GAMI spread at some higher power setting?
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Then for cruise we could set it at 16.5 or so for lop economy at 2250, which would work up to 2375.......For economy, pull back to 2370 or lower and it automatically goes to economy.
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Gentlemen, we realize that you're dialing the mixture knob to see GAMI spread, but let's return to a previous question regarding operation based on programmed mixture.
Is the system in fact stable enough that you can pull the prop knob to any RPM below 2370 at any altitude, and have every cylinder end up comfortably LOP, without touching the mixture trim knob? Or are you finding it necessary/prudent to tweak mixture manually?
Quote:
Originally Posted by Jesse
Chris, what was your percent power reading at that setting? I'm guessi about 45-50. That's amazing economy.
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154 KTAS at 8.5 GPH sounds pretty good for an RV-10. However, let's remember that the ability to run very lean is an ignition function. There are several brand choices available in high energy ignition, all of which can be installed with a mechanical injection or a carburetor for pretty much the same result. That includes EFII-branded ignition (SDS ECU + Subaru coil) without the fuel injection option.
If all six cylinders had a tight AF ratio spread, economy would be even better. Instead of some being near the lean limit, and some being just under peak, they would all be near the lean limit.
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Dan Horton
RV-8 SS
Barrett IO-390
Last edited by DanH : 05-24-2015 at 08:41 AM.
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05-24-2015, 09:58 AM
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Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,544
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I have been following this thread with interest, as I am really hopeful that a reasonably priced non mixture knob system can be made available. In 1998 I started balancing my injectors so that I could run my Rocket LOP. This was based on the work done by the folks at GAMI. Don Rivera was able to get me some inserts that would allow me to do this rather then use the expensive GAMI nozzles. I am not sure if anyone else had been doing this at that time. Since then I have balanced all my airplanes using this method. They run better at all fuel flow settings if they are balanced as close as you can reasonably get them.
And so after all these years, how do I fly my airplane?
If I am in cruise, at altitude, 65% power or less, I run my engine using the best power Lycoming charts.
If I am trying for an economy cruise for maximum range then I will go LOP. It is more efficient but I do lose at least 5% of my speed, 210 down to 200 or less knots. BTW at 65% power or less going from best power to LOP is about one gallon of fuel flow, which is an easy number to remember for the 540.
But what I do get with that loss of speed, is 5% MORE engine tach hours because I am in the air longer.
That is 5% more of more wear and tear on the engine. If one gets 2000 hours on an engine, then running LOP will meant that you get there 100 hours sooner then if you were running at best power.
I have not calculated what the savings in fuel LOP are vs the extra TBO engine costs because by the time everything is said and done, I don't care, I just want to go faster!
__________________
Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger
Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
Last edited by Tom Martin : 05-25-2015 at 08:10 PM.
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05-24-2015, 01:00 PM
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Join Date: Oct 2014
Location: WA
Posts: 70
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Quote:
Originally Posted by Tom Martin
I have been following this thread with interest, as I am really hopeful that a reasonably priced non mixture knob system can be made available. In 1998 I started balancing my injectors so that I could run my Rocket LOP. This was based on the work done by the folks at GAMI. Don Rivera was able to get me some inserts that would allow me to do this rather then use the expensive GAMI nozzles. I am not sure if anyone else had been doing this at that time. Since then I have balanced all my airplanes using this method. They run better at all fuel flow settings if they are balanced as close as you can reasonably get them.
And so after all these years, how do I fly my airplane?
If I am in cruise, at altitude, 65% power or less, I run my engine using the best power Lycoming charts. This puts me in the 50 to 100 ROP area, which as I understand it is quite safe.
If I am trying for an economy cruise for maximum range then I will go LOP. It is more efficient but I do lose at least 5% of my speed, 210 down to 200 or less knots. BTW at 65% power or less going from best power to LOP is about one gallon of fuel flow, which is an easy number to remember for the 540.
But what I do get with that loss of speed, is 5% MORE engine tach hours because I am in the air longer.
That is 5% more of more wear and tear on the engine. If one gets 2000 hours on an engine, then running LOP will meant that you get there 100 hours sooner then if you were running at best power.
I have not calculated what the savings in fuel LOP are vs the extra TBO engine costs because by the time everything is said and done, I don't care, I just want to go faster!
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Interesting thought about engine life. I run efii dual ignition on my Murphy w the io-540, . I fly much slower than an rv-10, but what I really like about LOP is my CHT temps are 40 degrees lower(360f)when LOP. I would guess for my application on a slow airplane where cooling can be a challenge, this probably more than makes up for the engine tach hours /life. I will use the efii system in my rv8, I am very happy with it.
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05-25-2015, 07:05 PM
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Join Date: Jan 2005
Location: Shorewood, WI (Milwaukee area)
Posts: 1,066
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Dan ? I'm sorry that I missed your reply. Thanks for getting back. My injection is mechanical. The figures were for the rich side of peak, probably about 100-150?. Thanks in advance for your thoughts... P.S. I have not been sure if my engine is completely broken in, and I've also been not sure how to lean with the 10:1 compression and what detonation dangers exist. At any rate I've been very tender with my leaning. With previous certified aircraft/engines I was used to operating (the leanest cylinder) at peak EGT (below 75% power) which seemed to give good results. Then learned that the richer cylinders might be operating in a bad area about 40-50 degrees ROP. Now am like the robotic character in "Short Circuit" - I need input... Thanks.
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Bill Dicus
Shorewood (Milwaukee) Wisconsin
RV-8 N9669D Flying 12/4/14!
Flying Pitts S-2A, Piper Lance
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