Notices
Part 135 Part 135 commercial operators

Caravan crash in Ohio

Old 12-20-2007, 06:42 AM
  #31  
Line Holder
 
Joined APC: Dec 2007
Posts: 27
Default

Originally Posted by lzakplt View Post
Why can't a conventionally configured airplane have a lifting tail, because your Jeppeson private pilot manual said so?
Geeze, if I did not know any better, that sounds a bit disrespectful.
I don't know you, you don't know me, or my education and experience. So instead of an off the cuff remark like that, how about explaining how what I posted is wrong?

"This is generally true but you have to distinguish between the center of lift as being that of the forward main wing, or taken as a combination of the main wing plus the aft-mounted tail. If the center of lift of the sum of the lifting surfaces is behind the center of gravity, then stability is maintained despite the possibility CG is behind the center of lift of the fore-mounted main wing.

As far as Caravan is concerned, what the tail does and when is beyond the scope of information currently available. A quick look at the approved CG range suggests it may have an uploaded tail at certain times. But one cannot know without access to tests and specific data. As far as I know the stability data for Caravan is not publicly accessible. Yesterday 08:38 PM"

The center of lift is always just that, the center of lift. I am not sure how you can include the stabilizer in the picture - the center of lift will show up somewhere about the MAC of the wing. I would LOVE to know how you can look at cg range and come up with the remark that at some point the *stabilizer* is responsible for some of the total lift force required.

Let me ask, do we agree that most (I say all) of the time, the stab is producing a down force? If yes, and you think at some point it produces a load supporting up lift, what happens right at the point where it transitions? Explain what you think stability will be like at that point? Or, what stability will be like if at any point in the flight will be like if the stab is actually lifting in the same direction of the wing? That would be one tough airplane to fly. I would think it would need a computer.

Your concepts of stability and control are far different than mine, and I am just asking for your explanation.

And no, thanks, I did not pick that up in a Jep Private pilot course, I got it by other means.
Lost is offline  
Old 12-20-2007, 08:52 AM
  #32  
Moderator
 
Cubdriver's Avatar
 
Joined APC: May 2006
Position: ATP, CFI etc.
Posts: 6,056
Default

Originally Posted by Lost View Post
...the center of lift is always just that, the center of lift. I am not sure how you can include the stabilizer in the picture - the center of lift will show up somewhere about the MAC of the wing. I would LOVE to know how you can look at cg range and come up with the remark that at some point the *stabilizer* is responsible for some of the total lift force required.

Let me ask, do we agree that most (I say all) of the time, the stab is producing a down force? If yes, and you think at some point it produces a load supporting up lift, what happens right at the point where it transitions? Explain what you think stability will be like at that point? Or, what stability will be like if at any point in the flight will be like if the stab is actually lifting in the same direction of the wing? That would be one tough airplane to fly. I would think it would need a computer.

Your concepts of stability and control are far different than mine, and I am just asking for your explanation...
This is an interesting and valid discussion, but I vote we move it to another thread out of respect for what started this one. I'll start one called "stability and control" later in Technical if no one else does.
Cubdriver is offline  
Old 12-20-2007, 10:00 AM
  #33  
Gets Weekends Off
 
Joined APC: Dec 2005
Position: pilot
Posts: 111
Default

you are right
not many caravan guys read technical how about a different thread here
185flier is offline  
Old 12-20-2007, 10:36 AM
  #34  
Gets Weekends Off
 
Joined APC: Feb 2006
Position: Master and Commander of Pipers and Cessnas
Posts: 126
Default

I don't think 185flier just made those transcripts up. They agree with information I've received. That information did make me scratch my head because it disagrees with what I learned in private pilot ground school.

I think that in the process of retracting t/o flaps the force on the Caravan tail switches from a down force to a lifting force. Under the wrong circumstances (low airspeed for example) the tail will stall at the point when tail force is switching from down to up. I think that's why Cessna's POH has revised the flap retraction speed significantly upward in the last 6 years.

I admit, reading "Aerodynamics for Naval Aviators" makes my eyes gloss over. A canard flies around with first a lifting horizontal stabilizer, followed by center of gravity, followed by center of wing lift. Why can't a caravan fly around with first center of wing lift, then center of gravity, then a lifting horizontal stabilizer?

Last edited by lzakplt; 12-20-2007 at 11:11 AM.
lzakplt is offline  
Old 12-20-2007, 10:41 AM
  #35  
Gets Weekends Off
 
Joined APC: Feb 2006
Position: Master and Commander of Pipers and Cessnas
Posts: 126
Default

A new thread is fine with me.
lzakplt is offline  
Old 12-20-2007, 01:21 PM
  #36  
Gets Weekends Off
 
Iflyfr8's Avatar
 
Joined APC: May 2005
Position: LJ35 PIC
Posts: 139
Default

Thanks guys, this is why I still like this forums over that "other" forum.
Iflyfr8 is offline  
Old 01-04-2008, 09:27 AM
  #37  
On Reserve
 
Joined APC: Mar 2006
Position: Former Freight Doggy
Posts: 17
Default

Hey IflyFr8,
How are things at LCK? Any new info on what happened? Has anybody mentioned weather the inertial seperator was open or closed on the Castle bird? I hope things are going well up there. Any word on the new turbo prop? The former starcheckers out here are pulling for you guys.


CMI
FlyCMI is offline  
Old 01-04-2008, 10:15 AM
  #38  
Gets Weekends Off
 
Iflyfr8's Avatar
 
Joined APC: May 2005
Position: LJ35 PIC
Posts: 139
Default

For the most part same old, same old.

I don't know if we will ever really know all the how's and why's, but it's very quiet and nothing new at the moment. It's just all around sad and very confusing.

Management has publicly said that there will be a new airplane on the property at the end of this new year. As far as I can figure out, it seems the (right now) conversation is focused on the BAE31 and SAAB340.

And that "drive" that we talked about so much before you left seems to have died!

Enjoying your new gig?
Iflyfr8 is offline  
Old 01-04-2008, 10:54 AM
  #39  
Line Holder
 
Joined APC: Dec 2007
Posts: 43
Default

Here is some of the other testimony, and it's not made up either, I ask why he (Dr. Kolman) would he say this statement about the tail if you are going to keep the uploaded tail theory going? Izakplt? 185flier?

It just does not make sense that a plane with that many years of service and over 20 million TO's and LDGs to have an issue that has been seen on one plane that you are referring to from the testimony When the lawyer for the plaintiff that sued Cessna admitted that ice was on the plane. I'm asking Why and given the testimony below.

Thanks for your time

14 Q So your assumption that he wasn't at 90 knots at 90 knots because
15 he stalled, right?
16 A That is correct
17 Q And you disregard the tail stall?
18 A The tail did not stall
19 Q Right, Circular logic?
20 A No, not at all. I think I've proved conclusively, not by
21 circular logic, but by objective engineering flight
23 tests, that the tail can not stall. It is physically
24 impossible for it to stall in that flight condition.

Last edited by Amigo; 01-04-2008 at 11:03 AM. Reason: added 185flier?
Amigo is offline  
Old 01-04-2008, 11:17 AM
  #40  
Line Holder
 
Joined APC: Dec 2007
Posts: 43
Default

Try going to www.cessnaelearning.com that site has a lot of information about the Caravan in Icing conditions.

Try it and see.
Amigo is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
LeoSV
Hangar Talk
2
07-19-2007 05:02 PM
ToiletDuck
Hangar Talk
1
07-18-2007 07:04 AM
RockBottom
Cargo
9
10-28-2005 12:56 AM
Gordon C
Hangar Talk
2
08-03-2005 05:35 PM
Gordon C
Hangar Talk
0
06-28-2005 05:19 AM

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
Trackbacks are On
Pingbacks are On
Refbacks are On


Thread Tools
Search this Thread
Your Privacy Choices