Mailing List flyrotary@lancaironline.net Message #38621
From: Thomas Jakits <rotary.thjakits@gmail.com>
Subject: Re: [FlyRotary] Carb and EFI was: [FlyRotary] Re: carbs vs efi
Date: Sat, 21 Jul 2007 11:15:40 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Damn,
 
I didn't get when Buly was pulling out!!
This is a serious loss, as he was really close!!
 
TJ

 
On 7/21/07, Ed Anderson <eanderson@carolina.rr.com> wrote:
Good Response, Bill.
 
Whether EFI or Carb, the fuel system is one of the two crucial systems in an aircraft - the other being ignition.  If either is not done carefully and attention to detail and good workmanship, problems will come - sooner or later, but, they will come. 
 
The EFI system produced by Tracy with its redundancy, many tuning modes, etc, is one I feel very comfortable flying.  Having had an after-market EFI fail completely (fortunately) on the ground, the comfort of redundancy with the RWS EC2 and its well thought out design has made the last 8 of my 10 years of rotary flight a pleasure.
 
  My personal perspective is that EFI simply gives me more insight and control over the engine's fuel parameters (note - that is not always  a good thing as it gives more opportunity to screw things up also) than a carburetor.  Having said that, once you get a carb tuned in then you can pretty much forget it.   
 
But, the very design features that permit the EC2 to be twixed and tuned to achieve the optimum fuel feed conditions are also those that can frustrate some.  It is clear that  some folks do not take the time to read (or perhaps having read it just don't  understand some aspects) Tracy's instructions - if you intend to vary from them then you better know as much (or more) than Tracy about EFI design and tuning.
 
  If you don't understand some aspect of the instructions - ask Tracy or even post it to this list - who knows, somebody may know {:>).  If you deviate from Tracy's instructions - then you have designed a new system with unknown (until tested) features {:>)
 
Either approach (carb or EFI) will fly the rotary just fine.  There are (as with most everything) some pros and cons to each and some folks simply feel more comfortable with one than the other.  Hey, that what this is all about - you get to do it you way.  Just do it with knowledge, experience (if you don't have any find someone who does) and eye to examining each component/connection with the attitude of if this should fail - what happens?  If you don't like what happens, then take the time, get the knowledge to minimize the probably of that component failing or the consequence of failure.
 
Well, back to my coffee
 
Ed
 
Kevin, not heresy at all. There are several factors here. First Tracy is doing some development work, but offering a very inexpensive EMS. Once you get everything right it should give great service. Ed Anderson is a good indicator that the system will run for a long time once dialed in. Some guys are doing fully redundant alternators AND batteries and not just because of the engine, rather a fully electrical panel. Go with what you feel secure with, and fly accordingly. I have posted before that mags can have trouble with high RPM engines. So unless you have an early front cover and are willing to run POINTS, you will still need an ignition.
 Most of the carb inquiries have been on account of George and Richard going with single rotors. I believe Richard may have a modified stocker ignition and a carbed P-port. He has done us all a great service building, and now testing a hybrid end plate. mostly aluminum, with a steel insert. (GOOD LUCK RICHARD!)  Lynn and I have both grafted old mopar EI ignitions on to other engines. These require battery power but are otherwise unkillable. Available for next to nothing from J.C. Whitney but you must do the set up and wiring yourself.
Tracy's system looks to be a good one, but you must realize that wiring and plumbing ABSOLUTELY MUST BE DONE PROPERLY. This is equally true of a Lycoming install, but more of the FWF or FWB (Canard) is available to you off the shelf. We lost Buly to some mistakes that he made with the wiring, not a complete failure, but intermittently causing him fail to start problems out of the blue. Buly is a good builder too and the troubles drove him and Tracy crazy. Only when he finally pulled his control box for an update could Tracy find the problem. He is putting in a Lyc. clone. This is a terrible loss for us. The problem was self generated, (he re-soldered a connector to gain clearance rather than re-do the panel), and that connector had the classically difficult to diagnose intermittent problem. Bully and family made the tough decision to forgo any further pioneering. To bad too, his plane would have been a great addition to the conversion "fleet."  The point here is, like flying a cross-country, plan the install and then stick to the plan. If you run into a bind do the needed rework and don't "make do."
 You can go with carbs or EFI, there are several, Tracy's is aviation redundant, and the cheapest though. You must be able to understand the needs of digital electronics to install ANY EFI or EMS. Troubleshooting wiring is always the toughest job!
This is a super long post already but I must tell you about a failure I had back in the days I did mechanics work to pay for school. I was doing a tune-up on a Kawasaki 175 single. Mag ignition 2 cycle, came in running for a regular service. I did points, timing, plug, carb adjustment, the works... After finishing my labors, THE DAMM BIKE WOULDN'T START! I checked spark with a test plug on the cylinder head and drained the float bowl to check fuel it was clean. This is the simplest engine in the world, a 2 stroke single! To cut to the chase the brand new SPARK PLUG was bad. I broke it apart later to check and found someone on the production line had left out the copper core connecting the top of the plug to the center electrode. The point is no matter how simple you think a job is it still requires logic and perseverance to be SURE everything is correct. And even "simple" stuff can fail.
 
Bill Jepson




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