A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Soaring
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

final glide estimates



 
 
Thread Tools Display Modes
  #1  
Old March 11th 06, 08:57 PM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.

Rough air speed is generally set so that a certain limit of turbulence
will not over stress the aircraft.

Todd
3S

  #2  
Old March 11th 06, 10:55 PM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

toad wrote:
This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.


Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.

Shawn
  #3  
Old March 12th 06, 02:56 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?


Shawn wrote:
toad wrote:
This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.


Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.

Shawn


This is true, at lighter weights the maneuvering speed goes down, since
the airframe is only strong enough for X g's.

Toad

  #4  
Old March 12th 06, 04:28 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

Shawn wrote:
toad wrote:
This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.


Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.


So, for gliders, the flight manual figure only applies if you are
carrying full water ballast, and you are supposed to guess at what is
when the glider is unballasted?

--
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

www.motorglider.org - Download "A Guide to Self-launching Sailplane
Operation"
  #5  
Old March 12th 06, 05:31 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

Eric Greenwell wrote:
Shawn wrote:

toad wrote:

This is the basic method to set maneuvering speed:

The Maneuvering Speed is the minimum speed at which the wing can
produce lift equal to the design load limit. (in positive G's) Below
this speed the wing can not produce enough lift to overstress the
aircraft, no matter what angle of attack is used.



Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.



So, for gliders, the flight manual figure only applies if you are
carrying full water ballast, and you are supposed to guess at what is
when the glider is unballasted?


No, just calculate it by taking the square root of the mass/max gross
and multiply that by Va, in the cockpit, in rotor, while dropping below
glide to the nearest safe field.
Simple!

The physics argument for Va decreasing with lower mass makes sense.
However, the legal argument for what maneuvering speed should be used
would support the notion of a constant Va at all weights.

Shawn
  #6  
Old March 12th 06, 10:33 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

Are you sure they would not use a worst case scenario?

Paul

Shawn wrote:


Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.

Shawn

  #7  
Old March 12th 06, 10:33 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

Are you sure they would not use a worst case scenario?

Paul

Shawn wrote:


Maneuvering speed assumes max gross weight. If you're flying lighter
the wing can make enough lift to break.

Shawn

  #8  
Old March 11th 06, 09:19 PM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

John Galloway wrote:

A quick scout through the BGA datasheets seems to show
a trend that for modern single seaters the rough air
and manouevring speeds are the same


Yes, but I don't believe it's really for technical reasons. I rather
suspect that the manufactorer defines it deliberately that way to keep
things simple for the pilot. (Quick test: Do you know whether the green
arc defines maneuvring speed or rough air speed?)

Stefan
  #9  
Old March 12th 06, 12:24 AM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

In article ,
Stefan wrote:

John Galloway wrote:

A quick scout through the BGA datasheets seems to show
a trend that for modern single seaters the rough air
and manouevring speeds are the same


Yes, but I don't believe it's really for technical reasons. I rather
suspect that the manufactorer defines it deliberately that way to keep
things simple for the pilot. (Quick test: Do you know whether the green
arc defines maneuvring speed or rough air speed?)


Manouevring.

Rough air places lower loads on a structure than do extreme control
deflections, so rough air speed will always be the same as or higher
than manouevring speed, never lower.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------
  #10  
Old March 13th 06, 12:45 PM posted to rec.aviation.soaring
external usenet poster
 
Posts: n/a
Default Rough air limit - how is it set?

On Sun, 12 Mar 2006 00:24:17 UTC, Bruce Hoult wrote:

: Rough air places lower loads on a structure than do extreme control
: deflections

Surely that depends entirely on just how rough the air is?

Ian
--

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Final Glide: Edward "Ted" Pearson [email protected] Soaring 1 December 4th 05 04:44 PM
Roger Ruch - Final Glide [email protected] Soaring 2 November 25th 05 09:12 AM
Final Glide - Allan MacNicol Roy Bourgeois Soaring 3 July 9th 05 06:53 PM
Australian Shareware Final Glide Calculator Neptune Soaring 0 September 6th 04 01:53 AM
Final Glide for Don Dorrell JJ Sinclair Soaring 2 December 2nd 03 02:56 PM


All times are GMT +1. The time now is 08:19 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 AviationBanter.
The comments are property of their posters.