Finally: The right-sized Thielert

("Aaron Coolidge" wrote)
They also expanded the STC for the 135hp unit to include a larger number
of PA28. Unfortunately on the PA28-180 the MGTOW is reduced from 2400 to
2150 lbs.


250 lbs!

Because of:
The engine swap weight difference?
A power difference?

....or a combination of the two?

Also, is there a rule of thumb to compare the new 135hp Diesel to 160hp or
180hp AvGas engines? On the face of it, it looks like 25-45 fewer hp with
the Thielert.


Montblack

On 2006-06-09, Montblack Y4-NOT wrote:
Also, is there a rule of thumb to compare the new 135hp Diesel to 160hp or
180hp AvGas engines? On the face of it, it looks like 25-45 fewer hp with
the Thielert.

The difference is I think the propeller that comes with the Thielert -
it's constant speed, so all things remaining equal you get more takeoff
thrust per horsepower.

--
Yes, the Reply-To email address is valid.
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de

In article ,
Dylan Smith wrote:

On 2006-06-09, Montblack Y4-NOT wrote:
Also, is there a rule of thumb to compare the new 135hp Diesel to 160hp or
180hp AvGas engines? On the face of it, it looks like 25-45 fewer hp with
the Thielert.

The difference is I think the propeller that comes with the Thielert -
it's constant speed, so all things remaining equal you get more takeoff
thrust per horsepower.

And you keep that power to a higher altitude (diesel is TURBO after all)
versus losing HP the moment you leave the ground (or the moment your
density altitude goes up)

On a 100dF day at any altitude, the difference would likely be in favor
of the thielert (especially with CS prop)

--
Chris Schmelzer, MD

Chris Schmelzer wrote:
: In article ,
: Dylan Smith wrote:

: On 2006-06-09, Montblack Y4-NOT wrote:
: Also, is there a rule of thumb to compare the new 135hp Diesel to 160hp or
: 180hp AvGas engines? On the face of it, it looks like 25-45 fewer hp with
: the Thielert.
:
: The difference is I think the propeller that comes with the Thielert -
: it's constant speed, so all things remaining equal you get more takeoff
: thrust per horsepower.

: And you keep that power to a higher altitude (diesel is TURBO after all)
: versus losing HP the moment you leave the ground (or the moment your
: density altitude goes up)

: On a 100dF day at any altitude, the difference would likely be in favor
: of the thielert (especially with CS prop)

The CS prop helps at takeoff so that the engine can make rated power at
zero airspeed. When moving at cruise speed, it makes no difference if the
engine has a CS prop or a FP prop if the RPM is the same (the FP prop
has the advantage here, because it's lighter).

Cruise power from the O-360 180 HP engine is 75% or 135 HP, obtainable
up to 7500 foot DA. I wouldn't expect to see any performance advantage
at or below this altitude.

The real advantage of the diesel seems to be the vastly reduced fuel flow,
which lets the standard Cherokee tankage get over 9 hours of flying time
(this is the application we're talking about here).
--
Aaron C.