Hi All
This engine type is saying a few things. First that you have a turbocharged engine with peak output at 115 HP. (914)
The F is a bit more complex. In the beginning any engines as Bill pointed out that were not in compliance to a TC, type certificate, they are designated as a UL. They are not accompanied with the documentation that would satisfy EASA or FAA to be used in a type certificated aircraft. the letter "F"was used as that model did comply with the FAA FAR 33 standard for certified use.
So the question of what is different...well not much. At birth the engine has a data plate assigned and all fits, tolerances, serial number of component parts and approvals are recorded on a master filemaker system at the factory. If it is certified, or an F engine, the tag background will be red and the serial range is different from the UL brother. A few components that are optional on the UL version, like the overload clutch, are mandatory to comply with the TC. So if you have an F version it will always have a clutch. Paperwork the certified is to be maintained to certified standards to retain its TC. it is my understanding that that would mean that you need to be an A&P or equivalent to do the work and sign the log. If however you have it fitted in your experimental then thats a different story. So we understand,, certified and maintenance of certified standards also means certified parts. While you would not recognize the difference the parts for certified must be accompanied by a Form 1 tag or country specific equivalent. Yes that means even spark plugs and bolts and screws. Otherwise it suggests your not maintaining it to standard.
One step more. The 80 HP 912 has a UL version, not certified. They additionally had a 912A version for motor gliders (Day VFR only to JAR Part 22H) and they have a certified version 912F (FAA part 33) With the introduction of the 912 100 HP engine they wanted to brag a bit, so the certified version is 912S (believe it or not the S stands for "super") and the uncertified is a 912 ULS....it gets worse.
The injected engine tossed a curve at us. the 912 (100 HP) iS, injected super. For certified they changed tune and it is a 912 iSc, injected super certified....and on we go. 915 iS, 915 iSc...now you get the pattern?
Cheers
