October 23, 2006                                                                                                 HOME
What Engine?        See the engine being built.

      

 

 

 

 

 

 

  
 I left all the decision making stuff below, but I decided on a 180 hp XP-360 and it will be built at the Eagle Engines facility in Redding, California.  First a bit about the final engine selection:
Compression - will be standard 8.5 to 1.  I want a wide range of future fuel options and keeping the compression standard keeps the few limited options open.
Roller tappet engine - for less camshaft wear because the cam is a common failure point on the opposed engines.
Heads will be flow-matched - even though it delivers only a slight improvement in smoothness and horsepower, I like knowing that each cylinder is getting an equal chance to breath.
It will be precision balanced - well, even though I've been behind nearly identical engines (one balance and one not) and I couldn't tell the difference, balancing just seems a reasonable thing to me.  I'm allowed a data-free decision now and then.
Aerosance FADEC - because I've spent many hours reviewing data, thinking and reasoning what works and what doesn't and it always comes back to FADEC being the right choice.  I considered Eagle EMS, but it has that awful fuel flow divider that is so common, fixed timing, an awkward battery charging arrangement and little or no real field data.
 
 
   
 

      This may be the only engine I can afford when I'm finished getting everything ready and buying all the tools!

Seriously, I've been going round & round about engines.  Here are some engines and engine providers that I have looked at with varying degrees of seriousness.

But First:     A few points about the engines I considered

Horsepower:   I ruled out the respectable 160 hp 320-series engines early in the game.  Part of why I decided on an RV, and particularly an RV-7, was performance.  So, an RV-7 performs well with 160 hp, but I know I want more.  Additionally, my airplane will be a little heavy.  I will have an autopilot, strobes, junk in the panel and probably stuff I haven't thought of yet.  Yep, I need the horsepower to make me happy!  But how much?  I'll stay within the design limits of the aircraft.

Experimental vs Certificated:   Hmmm, certificated, of course -- BUT WAIT!  What does that mean?  And, why?  Well, basically I decided it will be an engine designed for flight.  I am willing to take some experimental risk, just not too much.  Understanding how much risk is acceptable is not a clear cut step.  I do know that certified engines are fairly predictable.  Some experimental engines are, perhaps, equal or better.  After much reading and debate, I have concluded that there isn't any absolute truth around all this beyond the obvious point that the farther you get from tried and proven (in aircraft) the greater the risk.

Fuel Injection vs Carbureted:   I have made up my mind here.  Fuel injected it is.  The problem is, it isn't that simple.  I am still grinding through the fuel injection options.  It seems that most builders don't belabor this point too long, yet there are interesting options.  There's the typical system that uses a fuel flow divider to route fuel to each cylinder.  It simply pumps the fuel down one tube and into a small "divider" with one tube running out of it for each cylinder.  That means equal pressure to each injector, but not necessarily equal fuel flow.  Other systems pressurize separate lines for each cylinder.  There's an advantage in that a blockage in one injector will reduce it's flow, but it won't overly richen the other cylinders as would happen with a fuel divider.  Ah yes, then there is FADEC.  It manages both fuel and ignition (and sometimes the prop).  There is much to be said about this sophisticated system -- too much for me to get into it.

Normally Aspirated vs Turbocharged (turbo-normalized):   I really like the idea of maintaining performance to higher altitudes.  I am not sure I am willing to deal with the extra work it takes to manage a turbocharged engine in flight.  I also don't like the extra heat, weight and mechanical wear associated with turbocharging.  At this point, I think my engine will just have to breath naturally.

Constant Speed vs Fixed Pitch:  Constant speed, of course!  I'm leaning toward the Hartzell Blended Airfoil prop.  I am not thrilled with the operating limitations, but the performance is still better than even the considerably more expensive options.  But then, there are the RPM restrictions.  So, it's the blended airfoil aluminum MT.  It costs slightly more than the Hartzell, but without RPM restrictions.

Mags vs Electronic Ignition:  It will be all electronic.  I will have 2 independent (yes truly independent) electrical systems.  Not only will it be electronic, but will likely be FADEC.

 
  The Engines:   

DeltaHawk's engines don't represent a new principle, just a somewhat new approach.  It's a two-stroke water cooled diesel with expected performance that should make it a great airplane engine.  In August of 2004, I gave the engine serious consideration.  Only one had flown at that time and it simply wasn't ready for market.  It was clear it was a little too experimental for my tolerance, but they told me it would easily be available within a year.  As I came back to building and at the time of this writing a full 2 years later, it still isn't there.   It's a big risk to be someone's engine tester and that's what everyone who buys a DeltaHawk today will be.  It probably will be a fine engine.  I'll consider one when it has proven itself.  It rates a 3 on my 10-scale, but I look forward to seeing it flying successfully. 

 

Lycoming's certified engines have to be a first consideration.  That leads to the question of whether it should be 180 hp or the 200 hp (angle valve and dampened crankshaft) version.  Twenty more horsepower with the angle valve engine, but an extra 25 pounds or so.  Both are still in the running, but about 6 on my 0-10 scale.  If I were to buy one of these, I would purchase it from Vans.

  
Lycoming's "X" engines are experimental category engines made, of course, for the experimental market.  I have been considering the Lycoming IO-390x (yes, 390) since late 2004.  This is a heavier engine than the 360s (by 5 to 30 pounds or so).  For the extra weight, you get an extra 10 to 30 hp bringing it up to 210 in Lycoming stock form.  If I were to get the 390, it would be from Monty Barrett at BPA Engines.  This one is pulling about 5 on my 10-scale.  
The Subaru automobile engine has gained some popularity and Eggenfellner has done a very nice job in putting together a clean and complete firewall forward package.  They really do mean "firewall forward", delivering a complete engine already installed on the engine mount with almost everything attached.  It all comes together at a reasonable price and Eggenfellner does have a track record with a number that have been flying for a few years.  It's not for me and gets a 2 on my 10-scale all because it's an auto engine.  O. K., there are a few other reasons, but it is out of the running in my application.  
  Yes, it is a turbine!  The Innodyn turbine idea thrills me.  I have watched this engine develop for  a couple of years and I long for it.  At the same time, one has to be practical.  Not that this engine would not be practical.  There is much talk about the high fuel burn, but fuel cost with this engine (for me) would be quite modest.  I'd be happy to explain that, just not here.  This is an engine option with tremendous potential for homebuilders and beyond, if it works out.   The problem is, it doesn't seem to be progressing and the company doesn't communicate well.  They have had a few problems and, to their credit, have been honest about those problems.  When I talked with Innodyn staff at Oshkosh in 2005, they felt the engine deliveries would begin within 6 months.  I could commit to this engine, but as of this writing, the company has not responded to my emails and the engines are still not really available.  This could be an 8 on my scale, but at the moment it rates a 3.  I am too close to my engine decision to gamble further on a non-responsive company.  
The Superior XP-360 is my current choice.  I probably will settle for a 180 hp generic version rather than going for the higher compression.  I make that decision for all the usual reasons like reliability, fuel consumption, fuel costs and options etc.  But one overriding factor influences that decision more than the others.  That is, I want FADEC.  I am really impressed with the integration of FADEC into the engine management scenario and it's overall performance.  The additional fuel economy is attractive also.  One real nagging question about this engine is, "Where do I get it?"  Direct from Superior is one good option.  If I did that, I could assemble it myself at their build school.  On the other hand, I'd like a local provider.  For that I would go to Eagle Engines in Redding, CA.  That is only about 15 miles from home for me and I'd have someone close by to deal with problems should they arise.  There are many other choices, but right now, I'm struggling with wanting the supervised build option and local support, ugh!  The XP-360 hits a 9 on my 10-scale.  
     
I don't know why the Franklin 220 hp six-cylinder is not more popular.  It is a smooth running reliable engine and is relatively light weight for a six.  It would be a good engine for the RV even though it puts out more power than recommended by Vans.  I considered it.  As far as I know, it only comes carbureted and I don't know if any electronic ignitions work with it.  It gets a 5 on my 10-scale mostly because it is over my power limit and has only a carbureted version.  
 

Final Engine Choice:     Is the superior XP-360.  Yep, only 180 hp.

There are a few undecideds though.  First (and no small matter) is the question of who will build it.  I want to do it myself, but that is beyond me.  I want to go to the Superior Build School, but I also want to do business locally with the added advantage of local support.  If I can work out a way to build the engine myself in the local facility (EagleEngines ), I will get my engine there.  If not, it's directly from Superior.   See the engine being built.

 Another Issue is FADEC.  It's an issue because I'm not getting a response from Aerosance (the FADEC people).  Several people have told me they are slow in responding, even on serious maintenance issues.  Another option is the Eagle EMS.  It is FADEC-like, but not the same.  It doesn't meter fuel independently for each cylinder.  That's not the only difference, but I don't want to ramble as usual...

In the end, Eagle Engines was able to get the information I wanted from Aerosance.  It will be FADEC.

 
         
           
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A place for homebuilt aircraft engine or an experimental aircraft engine from Eagle Engines Redding CA.