Engine Designations

For reciprocating engines:

 VLHGATSIORL 550F
 ||||||||||| |  |
 ||||||||||| |  .->  FADEC (Full Authority Digital Engine Control)
 ||||||||||| .---->  The Engine displacement in cubic inches
 ||||||||||.------>  Liquid cooled engine
 |||||||||.------->  Radial engine
 ||||||||.-------->  Opposed engine.  Other valid letters are:
 ||||||||            I (Inline), V (V-engine), R (Radial), X (X-type)
 |||||||.--------->  Fuel injected
 ||||||.---------->  Supercharged (Engine can operate at manifold
 ||||||              pressures above 29.92)
 |||||.----------->  Turbocharged (Engine can maintain rated power
 |||||               at altitude (up to a certain maximum)
 ||||.------------>  A: Aerobatic engine (inverted oil system, dry sump)
 ||||                AE: Aerobatic engine (inverted oil system, wet sump)
 |||.------------->  Geared engine
 ||.-------------->  Helicopter engine
 |.--------------->  Left turning engine
 .---------------->  Vertical mount engine (for Opposed engines)

For turboprop engines:

  TP 500 ---->  500 shp turboprop

1. How are rotary engines specified, how about wankel engines?
2. Are there more variations for turboprop engines?
3. How are jet engines specified?

Aerobatics website
Soaring website
Landings Aviation Server