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Having a Good 912ULS Run….

Piper J3

Well Known Member
I bought my RV-12 from original builder with 48TT in October 2015. I just completed 75 hour oil change at 700TT. Airframe is early SN 120058 and engine was manufactured in Feb 2009.

Timeline and Observations:

  • Using Mobil1 4T 10W-40 synthetic motorcycle oil and genuine Rotax filter
  • Oil consumption is < 1L / 75 hours with lots of TO / Landings and engine at full power climb
  • Run 100% Mogas 93E10 from Costco (Tier 1 supplier)
  • I occasionally mix Marvel Mystery Oil @ 2 oz/10 gallons fuel for top-end lubrication
  • Magnetic plug in gearbox is clean with no ferrous metal fines
  • Differential cylinder compression test 87/84ish
  • Gearbox overload clutch and drive dogs feel/sound like new when burping engine
  • Always cruise just shy of 5500 RPM redline – 115 knots
  • Engine runs smooth – haven’t done dynamic prop balance yet
  • Engine is pre-heated at 40F and below
  • Replaced sparkplugs ~400TT
  • Replaced sparkplug caps ~400TT
  • Replaced voltage regulator with John Deere @ 100TT
  • Replaced broken front support bracket for CDI ignition modules
  • Cleaned carbs and replaced all rubber parts
  • Replaced one EGT thermocouple probe
  • Replaced fuel pressure sender per SB
  • Replaced oil hoses with conductive braided Teflon
  • Replaced carb floats with Bing at ~300TT
  • Now installing Marvel-Schebler Epoxy floats
  • Cleaned and re-oiled air filters twice – I operate off grass runway
  • Installed banjo-fitting hose at crankcase drain to increase muffler clearance
  • Replaced fuel hoses with conductive braided Teflon
  • Replaced coolant hoses with high-performance silicone heater hoses
  • TIG welded chromoly sleeve to repair cracked engine mount
  • Removed fiberglass cylinder cooling shroud per Van’s latest approval
  • Added two layers foil-lined fiberglass over fire sleeve on all fuel lines FWF
  • Original green-label CDI’s with no soft-start feature
  • Battery always on charger when plane is in hanger which allows fast cranking and no kick-back
  • Starter motor sprag clutch continues to work well
  • Now use cooling fan at open oil door to extract heat prior to engine restart

Engine is incredibly reliable – starts and runs like automobile engine. I only had one instance of partial power loss which I attribute to fuel vapor lock - it was a learning/pucker experience and I have taken steps and changed operating procedures to reduce recurrence.
 
Thanks Jim, great list of observations and I find it very encouraging. I am only at 230 hours, but still very impressed with this airplane and engine (912ULS).
 
Nice Post!

Nice post Jim! Forums tend to bring out the squeaky wheels as is natural because folks need help (myself certainly included).

While I'm only about 155hrs TT on my RV12/Rotax 912ULS, it's been such a great experience.

The Rotax 912ULS is a revelation. Gone are the days of worrying...---> will it start? Do I need to prime? How about I exercise the throttle? Carb Heat? Lean for best power? Lean for taxi? Hot start boogaloo? $6 AVGAS? Mag Timing? Fouled Plugs?

NONE of these issues. Turn the key, plane starts. Just like my car. NICE. It's SMOOTH. Premium Car Gas with Ethanol? No problem.

Sure you may need to occasionally carb balance, but it's really easy to do and quick once you get the 'gist'. I'll take that trade off for the benefits anytime. Maybe that's my only wish: 912is engine for fuel injection and increased range.

BUT the 912ULS (and RV12) does exactly as advertised. Tough to complain about that!
 
Another way to “look” at the 912ULS is it is mechanical FADEC with single-lever control. Mixture is self-adjusting via diaphragm in carburetor and no carb heat required with RV-12 installation. Couple that with liquid cooled heads, and shock-cooling is not a worry either.

If I were to build a RV-12 now I would go with simplicity, reliability, and weight saving of carb installation.
 
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