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  #11  
Old 09-06-2010, 01:00 PM
mfshook62 mfshook62 is offline
 
Join Date: Sep 2008
Location: Windsor, Ca
Posts: 130
Default Maniford Presssure

What role does manifold pressure have on the advance curve? What is the interaction between manifold pressure, rpm, and advance curve, or does anyone have a pmag look up table which shows this interaction?
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Mike Shook, RV-9A, Dynon HDX,
CPI-2 Ignition, Catto Prop, EAA 124

Last edited by mfshook62 : 09-06-2010 at 01:16 PM.
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  #12  
Old 09-06-2010, 02:55 PM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

Quote:
Originally Posted by mfshook62 View Post
What role does manifold pressure have on the advance curve? What is the interaction between manifold pressure, rpm, and advance curve, or does anyone have a pmag look up table which shows this interaction?
Mike,

The timing crave is proprietary to Emag, and I can only guess what the relationship between RPM and MAP are.

We just added the advance numbers to the EICommander's Timing Divergence Alarm screen:


The green indication on the left side of the display indicates the timing difference between the two ignitions, 2.0 degrees or less in this example. The chevrons indicate the current advance for the right (green) and left (red) ignitions. The vertical bars on the right report the health of the coil packs, wiring harness and plugs. Too low a number and you have a short or fouled plug, too high a number and you have an open lead or broken wire.

Flying with the above screen, our Beta tester found the following during a recent test flight:
Engine: 180 hp IO-360, CS Prop, and dual P-mags

Take off
RPM: 2700
MAP: Full throttle
Advance: ~ 27 deg

High Speed Cruise
RPM: 25
MAP: 25
Advance: ~ 29 deg

Low Speed Cruise
RPM: 2400
MAP: Unknown but lower than above
Advance: ~ 33 deg

This indicates that when the engine is working its hardest, the EPIs limit max advance but when it slows down and is lightly loaded, it can call up more advance. That is working as it should.

For those of you flying with the EICommander, this software update will be made available shortly.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html

Last edited by N941WR : 09-07-2010 at 08:42 AM.
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  #13  
Old 09-06-2010, 07:46 PM
fstringham7a fstringham7a is offline
 
Join Date: Mar 2005
Location: St. George
Posts: 973
Default RE:Hot Start ??

I have a Titan ECI IOX-360 in my RV7A with ram air induction. I am also running with dual 113 PMags. I am using the jumpers / with the MAP from the mags not coneccted to the MAP sensor. The engine has 100hrs on the hobbs and at ROP the cylinders are running with 1 the coolest, 4 next with 2 and 3 the hottest (365/385/395/400+ @ 8500 msl and 70 OAT @ 10.9 GPH LOP they nearly always break with 4 first then 3 then 2 then 1 (335/355/358/360 @ 8500 msl and 70 OAT) @ 6.8 GPH.

Cold start are flawless. Engine runs smooth all the way through taxi/run up / climb / cruise / landing / taxi to hangar / and shut down.....

Now for the hot start that is another question. (this is the only way I have found that will start the engine and I have nearly ????( there maybe one that I don't know about) tried them all).

1. Mixture full Rich
2. Master on
3. both PMags on
4 "clear prop"
5. turn on high pressure fuel pump
6. hit start

prop will turn maybe 10 times and the engine will begin to show life.

7. Let go the start bottom.
8. The engine will run rough ...but if I shut the fuel pump off to soon the engine will stop.
9. At a point in time about 5 seconds the fuel pump will be turned off.
10. Engine will still run but a bit rough and on a few occassions has back fired.
11. By the time run up is completed / and ready to launch the engine will finally run smooth but not as smooth as from the cold start.

NOW THE QUESTION..... Could this hot start problem be a PMag timing-set up problem? Or................

Frank @ 1L8 ...RV7A... Flying and Tracken MT-RTG
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  #14  
Old 09-06-2010, 09:00 PM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

Quote:
Originally Posted by fstringham7a View Post
I have a Titan ECI IOX-360 in my RV7A with ram air induction. I am also running with dual 113 PMags. I am using the jumpers / with the MAP from the mags not coneccted to the MAP sensor. ...

Now for the hot start that is another question. (this is the only way I have found that will start the engine and I have nearly ????( there maybe one that I don't know about) tried them all).

...

NOW THE QUESTION..... Could this hot start problem be a PMag timing-set up problem? Or................

Frank @ 1L8 ...RV7A... Flying and Tracken MT-RTG
My first question is, when did you have them last upgrade? If you haven't had them upgraded since Emag fixed the lost timing issue, get them in before your next flight.

By plugging the MAP line to the P-mags you force them to "retard to an operable, but much less efficient range."

The P-mags have a "shower of sparks" starting mode. This works below 200 RPM, IIRC.


I have suggested that people running injected set the RMSD (Run Mode Start Delay) on the left mag but leave the right RMSD set to 0.

The RMSD is the setting that keeps the E/Pmags from firing until X number of revolutions.

The thing to keep in mind is that the RMSD works for the first starting attempt only. Meaning that if your engine doesn't start and you have to use the starter a second time, there is no RMSD for the second attempt. To rest set this feature, you have to power cycle the E/P-mags.

On a cold start, use both mags and the right one will fire on the first revolutions.

On a hot start, use just the left ignition which will allow the engine to turn over a few times before firing the ignition.

Give that a shot and let us know how it works.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html

Last edited by N941WR : 02-09-2013 at 06:45 PM.
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  #15  
Old 09-06-2010, 10:18 PM
fstringham7a fstringham7a is offline
 
Join Date: Mar 2005
Location: St. George
Posts: 973
Default RE:Updates !!!

Bill

Thanks for the info.... My updates have all been complete...

Next time I have the cowl off I will give your suggestions a try. Plus I wished I was flush with more beans the EICommander looks like a great instrument to have for diagnositics

Frank @ 1L8 ...RV7A... Flying/Tracken MT-RTG
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  #16  
Old 09-07-2010, 07:10 AM
David-aviator David-aviator is offline
 
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
Default

Quote:
Originally Posted by N941WR View Post
Mike,

The timing crave is proprietary to Emag, and I can only guess what the relationship between RPM and MAP are.

We just added the advance numbers to the Timing Divergence Alarm screen


The green indication on the left side of the display indicates the timing difference between the two ignitions, 2.0 degrees or less in this example. The chevrons indicate the current advance for the right (green) and left (red) ignitions. The vertical bars on the right report the health of the coil packs, wiring harness and plugs. Too low a number and you have a short or fouled plug, too high a number and you have an open lead or broken wire.

Our Beta tester found the following during a recent test flight:
Engine: 180 hp IO-360, CS Prop, and dual P-mags

Take off
RPM: 2700
MAP: Full throttle
Advance: ~ 27 deg

High Speed Cruise
RPM: 25
MAP: 25
Advance: ~ 29 deg

Low Speed Cruise
RPM: 2400
MAP: Unknown but lower than above
Advance: ~ 33 deg

This indicates that when the engine is working its hardest, the EPIs limit max advance but when it slows down and is lightly loaded, it can call up more advance. That is working as it should.

For those of you flying with the EICommander, this software update will be made available shortly.
I have had EI (Electroair & Subby) with a timing advance meter of some sort. At WOT on take off timing always was around 24 degrees. What is the advantage of running at 27 degrees? I would be concerned about heat at that power setting.
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RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
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  #17  
Old 09-07-2010, 07:22 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

I corrected post #14. It is the RMSD that gets reset with a power cycle of the E/P-mags.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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  #18  
Old 09-07-2010, 07:33 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

Quote:
Originally Posted by David-aviator View Post
I have had EI (Electroair & Subby) with a timing advance meter of some sort. At WOT on take off timing always was around 24 degrees. What is the advantage of running at 27 degrees? I would be concerned about heat at that power setting.
David,

Under heavy load, such as at full power takeoff, most EI's limit the advance, 24 degrees in your example, to preclude pre-ignition.

At high altitudes and lower power settings, such as at cruise, most EI's will allow for greater advance settings.

The idea is that there is less fuel & air in the cylinders when operating at lower MAP's and it takes a longer time for the flame to propagate across the entire cylinder, so they can start it burning sooner.

At high power settings (MAP), the fuel/air mixture will burn faster because there is more fuel/air. Thus the EI's delay when to ignite the mixture until closer to TDC (Top Dead Center). If the mixture burns too fast or too far before TDC, the maximum pressure could be well before TDC, which you hear as engine destroying pinging.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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  #19  
Old 09-17-2010, 01:32 PM
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smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,918
Default Ahead of it's time...

Bill/David,

I purchased one of the first Electroair Ignitions from Jeff Rose back in the 90's for my RV4. I did alot of experimentation with my single mag, EI, spark plugs and Mag advance over the 1500 hours I flew my -4. I found that setting my non impulse coupled Bendix mag to 22 BTDC, EI installed standard (TDC) and using REM-37BY plugs for the Mag and Autolite 386 (18MM) plugs for the EI I achieved the best results. Starting was easy, no pre-ignition and always showed 8GPH at 20/2500 at 10,500 feet 165 knots true with 150 horses. EI advance was always around 33. My Rocket has the identical setup as my RV4. With GAMI injectors and the same plugs, Bendix Mag advance I achieve 10.5 GPH LOP at 20/2400 at 10,500 doing 185 knots true. (33 advance) Not bad for SIX cyllinders!

Jeff Rose once told me he set up a Long EZ with two EI's way back in the day. He installed one Hall effect at slightly before TDC and the other slightly post TDC. This gave him a very even burn across the power range.

I always start hot or cold on the EI, then bring the Mag on line when she fires. IO-540 procedure:
Cold: 3 seconds boost with mixture rich, throttle cracked, EI on, CLEAR!
Hot: Mixture lean, no prime, Mag/EI both on, throttle cracked, CLEAR! AS soon as it pops, Mixture rich, boost on.

Electroair still makes a fine system, I like the flexibility and efficiency.

My Dos Centavos...

Smokey
HR2
RVX

Last edited by smokyray : 09-17-2010 at 01:36 PM.
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  #20  
Old 09-17-2010, 04:04 PM
nomocom's Avatar
nomocom nomocom is offline
 
Join Date: Jun 2009
Location: Caldwell ID
Posts: 264
Default EI advance curve discovery

Quote:
Originally Posted by mfshook62 View Post
What role does manifold pressure have on the advance curve? What is the interaction between manifold pressure, rpm, and advance curve, or does anyone have a pmag look up table which shows this interaction?
The only reason we don't have a timing map is no one has taken the time to make one and share it. I only see three or four variables here, and each are controllable by simple tools.

Base timing
RPM
Manifold pressure
Ambient pressure
Could be done on a bench or in the airplane.

The EI commander can show timing advance so this would be easy to do and would be a benefit to the community here.

Why isn't EI sharing data?
In past conversations with Brad, he made it real clear they want to be a hardware seller, not the engine optimizers (the timing curve design/engineer). He stated he would like to see the engine sellers come up with their own timing maps via testing. So... basically they they aren't going to share what is going on inside the unit. My read on this, Brad knows builders want a bolt on solution and that a ignition system with no ignition map wouldn't sell very well. At the same time, they don't feel like they are the "timing experts" and their are other entities better suited to make those decisions. So, we are left to our own devices, but not that hard really, probably hardest thing to do is get the materials and protocol together, the testing might only take a few minutes.
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1990 RV-3 (now apart, upgrades in the works)
1959 C172 O-360
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