Author: "Luethi, Matt" <mluethi@...> Time: Wed Aug 22, 2001 4:03 pm PDT Link
Robert, what happens to the torque on the prop flange after the rpms have
been reduced by about half through a reduction drive?
Matt
-----Original Message-----
From: robert@p... [mailto:robert@p...]
Sent: Thursday, 23 August 2001 10:54 AM
To: RV7and7A@yahoogroups.com
Subject: [RV7and7A] Subaru EJ25 power curves
TWIMC and Larry,
I posted the EJ25 power curves on my builder's site at
http://protekperformance.com/rv7
Under : "Choosing an Engine"
Thanks for the data Al,
Robert Paisley (RV-7 underway)
Van's Air Force - World Wide Wing
www.vansaircraft.net
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Author: robert@... Time: Wed Aug 22, 2001 4:10 pm PDT Link
Matt,
Whenever you have a gear ratio inline you multiply the crankshaft
torque by the reduction ratio to calculate the final torque. I.e. if
engine torque is 160ft lbs and the reduction ratio is 1.81, the final
torque is 160 x 1.81 = 297ft lbs. (horsepower is unchanged)
Robert Paisley
--- In RV7and7A@y..., "Luethi, Matt" <mluethi@e...> wrote:
> Robert, what happens to the torque on the prop flange after the
rpms have
> been reduced by about half through a reduction drive?
>
> Matt
Author: "Luethi, Matt" <mluethi@...> Time: Wed Aug 22, 2001 4:26 pm PDT Link
Thanks for this Robert. So the torque will be greater after the reduction
drive. I am wondering what kind of torque a Lycoming engine with 160hp
developes... If say the Subaru has a higher torque force then that would be
a benefit for take-off and climb performance for the same prop if it were
fitted to a Lycoming engine? Maybe I am a little confused but we all discuss
horsepower but no torque and there is almost no mentioning about the
reduction drive and what it does to the final power which makes the prop
spin. I mean the reduction drive is one other obvious difference to the
setup with a traditional aircraft engine and it hardly gets any mentioning.
Matt Luethi
-----Original Message-----
From: robert@p... [mailto:robert@p...]
Sent: Thursday, 23 August 2001 11:11 AM
To: RV7and7A@yahoogroups.com
Subject: [RV7and7A] Re: Subaru EJ25 power curves
Matt,
Whenever you have a gear ratio inline you multiply the crankshaft
torque by the reduction ratio to calculate the final torque. I.e. if
engine torque is 160ft lbs and the reduction ratio is 1.81, the final
torque is 160 x 1.81 = 297ft lbs. (horsepower is unchanged)
Robert Paisley
--- In RV7and7A@y..., "Luethi, Matt" <mluethi@e...> wrote:
> Robert, what happens to the torque on the prop flange after the
rpms have
> been reduced by about half through a reduction drive?
>
> Matt
Van's Air Force - World Wide Wing
www.vansaircraft.net
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Author: eaainc@... Time: Wed Aug 22, 2001 5:35 pm PDT Link
In a message dated 8/22/01 7:05:26 PM Eastern Daylight Time, mluethi@e...
writes:
what happens to the torque on the prop flange after the rpms have
been reduced by about half through a reduction drive?
(end of quote)
Multiply the torque by the reduction ratio of 1.82
Jan
Author: eaainc@... Time: Wed Aug 22, 2001 7:35 pm PDT Link
In a message dated 8/22/01 8:51:46 PM Eastern Daylight Time,
robert@p... writes:
Bottom line, the Subaru 165 horse motor should perform very similarly
to the 160 horse Lyc.
Robert Paisley
(end of quote)
And it does exactly that in the Glastar :)
Jan
Author: eaainc@... Time: Wed Aug 22, 2001 7:42 pm PDT Link
In a message dated 8/22/01 8:51:46 PM Eastern Daylight Time,
robert@p... writes:
The Subaru (with Jan's drive) will turn 4914 rpm with the
prop at 2700rpm and make 162 ft lbs of torque at the crank. This will
yield 295 ft lbs at the prop.
(end of quote)
The Lycoming is Maxed out at 2700 propeller RPM. The initial power setting
in the Subaru airplane is 2900 propeller RPM to get you off the ground in a
hurry. Then the propeller automatically (after 40 seconds) reduces the RPM
to 2700
Jan Eggenfellner