Angle of attack and stick position - Page 2 - ED Forums
 


Notices

Reply
 
Thread Tools Display Modes
Old 07-12-2017, 10:10 PM   #11
Yo-Yo
ED Team
 
Yo-Yo's Avatar
 
Join Date: Apr 2003
Posts: 13,159
Default

Quote:
Originally Posted by Icaro_07 View Post
Do you know Whee i can get more info about this? And hay is more complex?
At different Mach numbers the critical AoA is different. And it starts to be noticable from relatively low M - 0.3...0.4. As the trimmed AoA is quite constant up to M > ~0.7 you see the effect you mentioned.
__________________
Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів
There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.
Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me
Yo-Yo is online now   Reply With Quote
Old 07-13-2017, 09:44 AM   #12
Vatikus
Member
 
Join Date: Aug 2016
Location: Slovenia
Posts: 481
Default

Here is a nice article wrt AoA and what is effecting it ...
http://www.boeing.com/commercial/aer...ack_story.html
Vatikus is offline   Reply With Quote
Old 07-14-2017, 07:09 PM   #13
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 3,807
Default

Quote:
Originally Posted by Icaro_07 View Post
...but the elevator can not stall if you hold a constant position = constant AOA,..
In reading your comments, I get the impression that you are confusing pitch with AoA. The two are not identical. At any particular pitch angle, your AoA will vary with speed even though your nose (and consequently your wing) is pitched up or down by the same amount throughout.

EDIT:
Quote:
Originally Posted by Icaro_07 View Post
Does any one knows if for every trim setting a stick position corresponds to an specific AOA because if it's that way it stalls at different AOA
So to answer your original question, no. Not until you take your airspeed into consideration. At a given airspeed, a given stick position will yield a particular AoA. Or inversely, a particular AoA (not pitch) with a particular stick position will give you a specific airspeed. But you can only calculate the inverse, if you know your wing's AoA. Otherwise you're missing part of the equation.
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.

Last edited by Ironhand; 07-14-2017 at 07:28 PM.
Ironhand is offline   Reply With Quote
Old 07-17-2017, 07:00 PM   #14
Icaro_07
Junior Member
 
Join Date: Jan 2016
Posts: 18
Default

Well is just that simplistic, fly the f-5 and for every position the stick moves corresponds to specific AOA
Icaro_07 is offline   Reply With Quote
Old 07-17-2017, 10:31 PM   #15
Yo-Yo
ED Team
 
Yo-Yo's Avatar
 
Join Date: Apr 2003
Posts: 13,159
Default

Quote:
Originally Posted by Icaro_07 View Post
Well is just that simplistic, fly the f-5 and for every position the stick moves corresponds to specific AOA
Different planes have different Mach-dependant trim curves. F-5 wing is a very different thing comparing to the conventional airfoil high-aspect non-swept wing of WWII planes. Moreover, even WWII planes had very noticable differencies either in CLmax(M) or trim curves vs M.
For example, P-51 CLmax(M) had very distinctive "shelf" at moderate M, though other planes had constantly decreasing dependance. Spitfire was more preferrable regarding high-M trim changes than P-51 and P-47, tc.
__________________
Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів
There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.
Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me
Yo-Yo is online now   Reply With Quote
Old 07-17-2017, 11:08 PM   #16
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 3,807
Default

Quote:
Originally Posted by Icaro_07 View Post
Well is just that simplistic, fly the f-5 and for every position the stick moves corresponds to specific AOA
Are you saying that, if you hold the stick in one position, the AoA will not change even when your airspeed changes? If so, I'm not buying it. Whether in the F-15, F-5, P-51, Dora, or any other aircraft, the AoA will get smaller as your speed increases and larger as your speed decreases, if you do not change the stick position.

EDIT: But, of course, I reserve the right to be wrong...
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.

Last edited by Ironhand; 07-18-2017 at 12:22 AM.
Ironhand is offline   Reply With Quote
Old 07-18-2017, 11:35 AM   #17
acdelta57
Member
 
acdelta57's Avatar
 
Join Date: Apr 2016
Location: Texas USA
Posts: 560
Default

AoA is the same principle for all aircraft. AoA is the angle between the wing chord line and relative wind. This has nothing to do with speed, pitch, roll or whatever. Each wing has a Critical angle of attack. This critical aoa will remain the same, but the factors causing the wing to reach that critical aoa may differ. Speed, bank, pitch just to name a few. This is why a wing will stall at any speed.

So to answer the OPs question, no, "stick position" has nothing to do with critical AOA. The relationship between the wing and relative wind are the only thing that will impact the aircraft and its stall. Now what you do with the stick to place the wing at its critical aoa is a different story.
__________________
1000 miles of road will take you around town, a 1000 feet of runway can take you around the world...unless your in a Huey, you can go anywhere with no runway in a Huey!

multiplayer name ''DustOff=3=6''
acdelta57 is offline   Reply With Quote
Old 07-18-2017, 04:52 PM   #18
Yo-Yo
ED Team
 
Yo-Yo's Avatar
 
Join Date: Apr 2003
Posts: 13,159
Default

Quote:
Originally Posted by Ironhand View Post
Are you saying that, if you hold the stick in one position, the AoA will not change even when your airspeed changes? If so, I'm not buying it. Whether in the F-15, F-5, P-51, Dora, or any other aircraft, the AoA will get smaller as your speed increases and larger as your speed decreases, if you do not change the stick position.

EDIT: But, of course, I reserve the right to be wrong...
Your statement is right only if you add "for the same lift" or "for 1 g level flight" as a part of this conditions.

Generally, for the STABLE airplane you need to push the stick forward as the speed increases to maintain this constant lift. By the way, for the neutral stability for fixed stick its position remains the same, but, anyway, you need to decrease AoA with double movement (push, then return to the same position to hold new AoA).
__________________
Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів
There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.
Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me
Yo-Yo is online now   Reply With Quote
Old 07-18-2017, 06:43 PM   #19
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 3,807
Default

Quote:
Originally Posted by Yo-Yo View Post
Your statement is right only if you add "for the same lift" or "for 1 g level flight" as a part of this conditions.

Generally, for the STABLE airplane you need to push the stick forward as the speed increases to maintain this constant lift. By the way, for the neutral stability for fixed stick its position remains the same, but, anyway, you need to decrease AoA with double movement (push, then return to the same position to hold new AoA).
Yes, I had 1G flight in mind. Should have stated that. I assumed that was the case, since the OP was asking about trim settings.
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.
Ironhand is offline   Reply With Quote
Old 07-21-2017, 03:58 AM   #20
Icaro_07
Junior Member
 
Join Date: Jan 2016
Posts: 18
Default

Well don't believe to me, check the F-5 trim the stick and check the AoA regardless of speed portion etc holds constant AOA
Icaro_07 is offline   Reply With Quote
Reply

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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 08:07 AM. vBulletin Skin by ForumMonkeys. Powered by vBulletin®.
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.