Search the archive:
 YaBB - Yet another Bulletin Board
 
   
 
  Simviation Forum › Current Flight Simulator Series › Flight School › Prop Feather : How & why?
(Moderators: Mitch., Fly2e, ozzy72, beaky, Clipper, JBaymore, Bob70, BigTruck)
‹ Previous Topic | Next Topic ›
Page Index Toggle Pages: 1
Send Topic Print
Prop Feather : How & why? (Read 891 times)
Jul 7th, 2010 at 8:53pm

ShaneG   Offline
Colonel
I turned into a Martian!

Posts: 10000
 *****
 
I've been flying the FS9 Baron 58 quite a bit,
and I've been messing with the prop feather knob
setting it to what I think it's for,
and now I'd like to actually know why it's there,
and how to use it properly.    Smiley
 
Back to top 
IP Logged
 
Reply #1 - Jul 7th, 2010 at 9:13pm

DaveSims   Offline
Colonel
Clear Lake, Iowa

Gender: male
 Posts: 2453
 *****
 
By prop feather, I'm assuming you mean the prop control lever?  Brett can say it better than I can, and I think this will help answer your questions.

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?num=1212879811
 
Back to top 
IP Logged
 
Reply #2 - Jul 7th, 2010 at 9:17pm

ShaneG   Offline
Colonel
I turned into a Martian!

Posts: 10000
 *****
 
Thanks for that link!  Smiley

I guess I've been doing it right then.  Grin

I figured it was more or less for better control of prop RPM for varying situations. 




 
Back to top 
IP Logged
 
Reply #3 - Jul 7th, 2010 at 9:19pm

DaveSims   Offline
Colonel
Clear Lake, Iowa

Gender: male
 Posts: 2453
 *****
 
I've always heard the comparison to a transmission on a car.  It allows the prop to take a bigger bite of air while turning at a slower speed, thus reducing wear and tear, noise, and increasing efficiency.
 
Back to top 
IP Logged
 
Reply #4 - Jul 7th, 2010 at 9:23pm

ShaneG   Offline
Colonel
I turned into a Martian!

Posts: 10000
 *****
 
That's a good comparison.  Cool

After I reach cruising altitude, I'll set my mixture, and then reduce the prop levers (blue ones) until they're around 2500RPM, and then reduce the throttle to lower the MP.

It 'sounds' right by the pitch of the engine hum, so I thought I was on the right track, and decided I should find out.  Wink
 
Back to top 
IP Logged
 
Reply #5 - Jul 7th, 2010 at 9:40pm

DaveSims   Offline
Colonel
Clear Lake, Iowa

Gender: male
 Posts: 2453
 *****
 
Actually you would want to reduce the throttles before the propellers.  I always think of it this way, you want the propeller control to always be higher than the throttle, so throttle gets reduced before prop, and prop gets increased before throttle.  You want to avoid high MP/low RPM, as it puts a lot of load on the driveshaft and governor, which could cause engine damage.  For most non-turbo engines, it is normal to use the rule of squares, 25' MP/2500 RPM, 24' MP/2400 RPM, etc..  It usually varies slightly between different types of aircraft, but the rule of squares will usually work out on most normally aspirated piston engines.
 
Back to top 
IP Logged
 
Reply #6 - Jul 7th, 2010 at 9:43pm

Brett_Henderson   Offline
Colonel
EVERY OUTER MARKER SHOULD
BE AN NDB

Gender: male
 Posts: 3593
 *****
 
We had a good discussion about this in the flight-training section..  I'll go find the link..

This thread isn't too far off.. it hasn't gone down the path where the prop-control is described as a pilot's means to control blade pitch.

HOWever, on a twin, where actual feathering is possible, it does become a direct control of prop-pitch by forcing (or in the case of most twins, allowing), the blades to feather.

But for normal operations.. the prop control is simply an RPM selector... and then the constant-speed prop applies the blade-pitch needed to maintain that RPM.. where airspeed and MP actually determine blade-pitch..
 
Back to top 
IP Logged
 
Reply #7 - Jul 7th, 2010 at 9:45pm

ShaneG   Offline
Colonel
I turned into a Martian!

Posts: 10000
 *****
 
DaveSims wrote on Jul 7th, 2010 at 9:40pm:
Actually you would want to reduce the throttles before the propellers.  I always think of it this way, you want the propeller control to always be higher than the throttle, so throttle gets reduced before prop, and prop gets increased before throttle.  You want to avoid high MP/low RPM, as it puts a lot of load on the driveshaft and governor, which could cause engine damage. 



That's the kind of tip I was looking for, and probably why I'm still blowing the engines when I use the realengine gauge while in flight.

I've got the settings about right, but it appears my order of procedure is off.  I'll give that a go then.   Smiley
 
Back to top 
IP Logged
 
Reply #8 - Jul 7th, 2010 at 9:48pm

DaveSims   Offline
Colonel
Clear Lake, Iowa

Gender: male
 Posts: 2453
 *****
 
Brett_Henderson wrote on Jul 7th, 2010 at 9:43pm:
We had a good discussion about this in the flight-training section..  I'll go find the link..

This thread isn't too far off.. it hasn't gone down the path where the prop-control is described as a pilot's means to control blade pitch.

HOWever, on a twin, where actual feathering is possible, it does become a direct control of prop-pitch by forcing (or in the case of most twins, allowing), the blades to feather.

But for normal operations.. the prop control is simply an RPM selector... and then the constant-speed prop applies the blade-pitch needed to maintain that RPM.. where airspeed and MP actually determine blade-pitch..


Haha, I knew you would show up.  This thread has Brett written all over it!

*Brett, the un-offical, offical FS flight instructor   Grin
 
Back to top 
IP Logged
 
Reply #9 - Jul 7th, 2010 at 9:51pm

Brett_Henderson   Offline
Colonel
EVERY OUTER MARKER SHOULD
BE AN NDB

Gender: male
 Posts: 3593
 *****
 
LOL   Cheesy

Here's the thread:

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?num=1212879811
 
Back to top 
IP Logged
 
Reply #10 - Jul 7th, 2010 at 9:53pm

DaveSims   Offline
Colonel
Clear Lake, Iowa

Gender: male
 Posts: 2453
 *****
 
Brett_Henderson wrote on Jul 7th, 2010 at 9:51pm:
LOL   Cheesy

Here's the thread:

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?num=1212879811


Yep, I beat you to that link on the second post of the thread.  I remembered the discussion, and figured it would be easier to redirect Shane to it rather than rehash it all over again. Wink
 
Back to top 
IP Logged
 
Reply #11 - Jul 8th, 2010 at 6:46am

ShaneG   Offline
Colonel
I turned into a Martian!

Posts: 10000
 *****
 
And thank you both!

Made it through an entire flight using the realengine gauge, and no blown engine!  Smiley

Flying realistically makes FS so much harder to do, but SO much more rewarding when you pull it off. Smiley
 
Back to top 
IP Logged
 
Page Index Toggle Pages: 1
Send Topic Print
‹ Previous Topic | Next Topic ›
  « Home ‹ Board Top of this page

Simviation Forum » Powered by YaBB 2.5 AE!
YaBB Forum Software © 2000-2010. All Rights Reserved.

Valid RSS Valid XHTML Valid CSS Powered by Perl Source Forge