 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
elmar.hegenauer(at)telus.
Guest
|
 Posted: Sun May 04, 2008 9:59 pm Post subject: > Re: would a full feathering propeller help? |
 |
|
Thanks Brian, I've meant
in a case of emergency
with a dead engine and
a windmilling propeller.
cheers
Elmar
--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
 |
netmaster15(at)juno.com
Guest
|
| Posted: Mon May 05, 2008 1:50 am Post subject: > Re: would a full feathering propeller help? |
|
|
Elmar, Of course it would cut the drag of the windmilling prop; the problem is that a full feathering prop would be so heavy that it would significantly alter the CG by its forward moment. Remember , with a "dead"engine there has to be an electrical motor to drive the blades into the feathering range. This adds to the weight of the full feathering prop. If it were so simple it would have been done already. Full feathering props are both heavy and more expensive
Cheers,
Cliff Umscheid-- "Elmar Hegenauer" <elmar.hegenauer(at)telus.net> wrote:itsforward moment
--> Yak-List message posted by: "Elmar Hegenauer" <elmar.hegenauer(at)telus.net>
Thanks Brian, I've meant
in a case of emergency
with a dead engine and
a windmilling propeller.
cheers
Elmar
--
Using Opera's revolutionary e-mai================================================================================================================================================sp; -Matt Dra=========================================
_____________________________________________________________
Ultimate Travel Deals - Click Now!
[quote][b]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
cjpilot710(at)aol.com
Guest
|
| Posted: Mon May 05, 2008 5:51 am Post subject: > Re: would a full feathering propeller help? |
|
|
In a message dated 5/5/2008 5:51:57 A.M. Eastern Daylight Time, netmaster15(at)juno.com writes:
The drag of a wind milling prop is enormous. A B-17 with just one wind milling prop can just barely maintain altitude at gross weight. With the prop feathered, its almost a "non issue". On the B-24 it is a serious situation at any weight. The old Piper Apache was the same (in actuality you really got a decent glide out of it with one engine feathered).
In reality yes, a full feathering prop would be heavier but not that much. One only need to look at the feathering systems on the light twins. The difference in the prop hub would not be so much as to mass but to the gearing inside. A feathering pump might add 10 lbs. I am willing to bet that there is already a full feathering prop for the M-14p out there somewhere. I believe Yak built a high wing twin that used M-14p engines. You are correct - full feathering prop can be more expensive.
There are some hangar stories of how some who have lost an engine, had the presents of mind, to pull up to near a stall and be able to get the prop stopped and "soar" their airplane home. Well maybe, but I have seen it done at airshows and it is surprising the vast difference in gliding ability of the airplane. You might want to conceder doing that if you are already high and want more time and distance before the inevitable.
The full feathering prop was designed because of the advent of the multi engine airplane. Multi engines were first put on aircraft to increase payload. It was recognized early that engines quit and besides the asymmetrical trust the drag of the wind milling engine was enormous. Hence the full feathering prop. Can you imagine try to coats a Goliath bomber of WW1 to fly with an engine wind milling?
So the question is - if the out come is no different - why put expensive and complicated system on the airplane?
Jim "Pappy" Goolsby
| Quote: |
Elmar, Of course it would cut the drag of the windmilling prop; the problem is that a full feathering prop would be so heavy that it would significantly alter the CG by its forward moment. Remember , with a "dead"engine there has to be an electrical motor to drive the blades into the feathering range. This adds to the weight of the full feathering prop. If it were so simple it would have been done already. Full feathering props are both heavy and more expensive
Cheers,
Cliff Umscheid-- "Elmar Hegenauer" <elmar.hegenauer(at)telus.net> wrote:itsforward moment
--> Yak-List message posted by: "Elmar Hegenauer" <elmar.hegenauer(at)telus.net>
Thanks Brian, I've meant
in a case of emergency
with a dead engine and
a windmilling propeller.
cheers
Elmar
|
Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food.
[quote][b]
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
elmar.hegenauer(at)telus.
Guest
|
|
| Back to top |
|
|
brian-1927(at)lloyd.com
Guest
|
| Posted: Mon May 05, 2008 8:53 am Post subject: > Re: would a full feathering propeller help? |
|
|
On May 5, 2008, at 2:46 AM, netmaster15(at)juno.com wrote:
| Quote: | Elmar, Of course it would cut the drag of the windmilling prop; the
problem is that a full feathering prop would be so heavy that it
would significantly alter the CG by its forward moment. Remember ,
with a "dead"engine there has to be an electrical motor to drive the
blades into the feathering range. This adds to the weight of the
full feathering prop. If it were so simple it would have been done
already. Full feathering props are both heavy and more expensive
|
Electric motor? Not since the 40's. Try one with a simple hydraulic
accumulator. There just isn't that much difference in weight.
Brian Lloyd 3191 Western Drive
brianl AT lloyd DOT com Cameron Park, CA 95682
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
