C172 Magneto question

[NYCPilot]

This formula usually yields an approximation if not an accurate figure, so don't rely entirely on it.

I do have a question though, the difference between the late model 172R and 172S is the HP, 160 and 180 respectively. Although the aircraft are exactly the same, what is the main difference in the engine that causes the increase in HP from 160 to 180?


Redline is pretty low, maybe 2400.
I flew mostly Pipers in training and they usually go to about 2700, so it was surprising that these newer 172's were redlined at a much lower RPM.

 

[TrafficInSight]

This formula usually yields an approximation if not an accurate figure, so don't rely entirely on it.

I do have a question though, the difference between the late model 172R and 172S is the HP, 160 and 180 respectively. Although the aircraft are exactly the same, what is the main difference in the engine that causes the increase in HP from 160 to 180?


Redline is pretty low, maybe 2400.
I flew mostly Pipers in training and they usually go to about 2700, so it was surprising that these newer 172's were redlined at a much lower RPM.

RPM limit and prop are what they usually use to de-rate an engine, so it's not your imagination.

 

[avbug]

There is no "I" in "Magneto"...it's all in the "O"!

Perhaps you meant to say "There is no "I" in "Team Magneto"...it's all in the "O!"

 

[FN FAL]

Perhaps you meant to say "There is no "I" in "Team Magneto"...it's all in the "O!"

Actually, you got a point there and I'm not talking about the one on your head ...aren't most GA magneto assemblies run off a singe drive?

 

[erj-145mech]

aren't most GA magneto assemblies run off a singe drive?

No, there are no TCM engines with dual mags, and only the Lycoming engines with the letter "D" in the model suffix (ie, TIO-540-J2BD, or O-540-E1A6D)have the dual mags.

 

[Vector4fun]

No, there are no TCM engines with dual mags, and only the Lycoming engines with the letter "D" in the model suffix (ie, TIO-540-J2BD, or O-540-E1A6D)have the dual mags.

?????!

Are you refering to new engines only?

 

[erj-145mech]

Everything built between 1970 and now. Including the TCM Tiarra series engines.

 

[Vector4fun]

OK, we're (I'm) getting terms confused here. (I think) If by "dual mags" you mean two mags on one drive, then my Lycoming O-320 E2D most certainly has two, separate, individualy driven Slick magnetos.

If by "dual mags" you did mean two, separate, individualy driven mags, well, there sure are a lot of O-200s, O-300s, and O-470s etc. around with those thingys...

 

[Gutenberg]

The R has a higher pitch on the prop
The S has lower pitch

The R does 90 at 1600 or so rpm (but climbs like an old man on one of those inclined treadmills), the S needs about 1900 for the same speed, but climbs better.

 

[erj-145mech]

OK, we're (I'm) getting terms confused here. (I think) If by "dual mags" you mean two mags on one drive, then my Lycoming O-320 E2D most certainly has two, separate, individualy driven Slick magnetos.

If by "dual mags" you did mean two, separate, individualy driven mags, well, there sure are a lot of O-200s, O-300s, and O-470s etc. around with those thingys...

I guess I wasn't clear on the "D" suffix, its in the 4th or 5th position. Thats basic knowlege in engine model designation. The 76 series engine that came standard on the 172N (1977-1980) was an O-320-H2AD, and it has a D4LN-2031 magneto. The "D" means that its a dual mag, that means it has one rotating magnet and two pole shoes and two distributors. The "4" means that it is for a four cylinder engine. The "L" means left hand rotation (for the mag, not the engine). The "N" means that it has a base type mount, vs, a base type mount. The 2031 is the series magneto.

A dual mag is either a D-2000 or D-3000 series Bendix, now TCM magneto. Thats also basic engine knowlege.

I'm sorry that I didn't elaborate more fully, I just assumed you had more working knowlege of a reciprocating aircraft engine ignition system.