Engine designator question

[jharper aaatttt cisco dddooottt com]

I know what *most* of the letters that show up in engine designators
mean (e.g. TSIO-540, AEIO-540), but there are two I can't figure
out and can't find any information about, viz S and E. They seem to show
up with T (turbo) and A (aerobatic/inverted) respectively, but that
do they actually mean?

Thanks,

John

[Jim Weir]

The "S" associated with T (i.e. TSIO-540) means supercharged. Turbo is not the
only method of supercharging. There have been engines built with the
supercharge compressor being engine-driven, electric motor driven, and
wind-driven. Turbo (driving the supercharger off the exhaust gas stream) is
just the currently popular way of doing it.

"E", so far as I know, is just an archaic way of designating "Engine" before we
had the current "O" for opposed and other minor variants. However, I am not
absolutely sure on this one.

Jim




"jharper aaatttt cisco dddooottt com" <"jharper aaatttt cisco dddooottt com">
shared these priceless pearls of wisdom:

->I know what *most* of the letters that show up in engine designators
->mean (e.g. TSIO-540, AEIO-540), but there are two I can't figure
->out and can't find any information about, viz S and E. They seem to show
->up with T (turbo) and A (aerobatic/inverted) respectively, but that
->do they actually mean?
->
->Thanks,
->
-> John


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Peter Duniho]

"jharper aaatttt cisco dddooottt com" <"jharper aaatttt cisco dddooottt
com"> wrote in message news:1092845688.169721@sj-nntpcache-5...
> I know what *most* of the letters that show up in engine designators
> mean (e.g. TSIO-540, AEIO-540), but there are two I can't figure
> out and can't find any information about, viz S and E. They seem to show
> up with T (turbo) and A (aerobatic/inverted) respectively, but that
> do they actually mean?

The "S" is actually part of "TS", which stands for "TurboSupercharged". I
believe, but am not certain, that the "E" is similarly part of "AE", as in
"AErobatic".

Pete

[Bob Moore]

"jharper wrote

> I know what *most* of the letters that show up in engine designators
> mean (e.g. TSIO-540, AEIO-540), but there are two I can't figure
> out and can't find any information about, viz S and E. They seem to
show
> up with T (turbo) and A (aerobatic/inverted) respectively, but that
> do they actually mean?

Nomenclatura

Lycoming's specific convention for post-WWII aircraft piston engine
designation is as follows. Note that this convention is fairly standard
and applicable to many other manufacturers.

C-D-M

Where:
C Letters indicating the engine's configuration:
I Fuel injected
O Opposed type (pancake-style)
X X-type engine
R Radial type engine
G Engine is geared
T[S] Engine is turbocharged
S Engine is supercharged, EXCEPT for
most Continental TURBOcharged engines. These
are designated "TS". See below.
L Engine is liquid-cooled or left-turning (ugh!)
A Engine is designed for aerobatics (DRY SUMP)
AE Engine is designed for aerobatics (WET SUMP)
M Engine is designed for unmanned drone
H Engine is designed for helicopter installation
V Engine is designed to have the crankshaft in
the vertical, not horizontal, plane.

D The engine's displacement in cubic inches.

M The manufacturer's "data" - often indicating
what types of accessories or engine revisions.


Bob Moore