Notices
Control Lines For all you fly-by-wire fanatics!

Too High

Old 10-18-2015, 07:37 PM
  #26  
Thread Starter
 
Join Date: Sep 2013
Location: Baraboo, Wisconsin
Posts: 143
Likes: 0
Received 1 Like on 1 Post
Default

Hmm.., John. I'm at two inches now, but could go down to one-inch separation easily enough. Nice to have another, simpler option.

DaveyMo

PS: What's the PIO abbreviation mean?
D....
Old 10-19-2015, 06:05 AM
  #27  
My Feedback: (1)
 
JohnBuckner's Avatar
 
Join Date: Dec 2001
Location: Kingman, AZ
Posts: 10,441
Likes: 0
Received 10 Likes on 10 Posts
Default

Good morning Davey. No one inch is too big of a jump from two. I would start by simply going down just one quarter inch to one and three quarter inchs at the handle If you do not have a handle that will support that small adjustment just make one they are simple to do. That is a perfectly reasonable handle line spacing when used with the typical sized 1/2A bellcrank.

PIO stands for pilot induced oscillation.

John
Old 10-19-2015, 10:00 AM
  #28  
Thread Starter
 
Join Date: Sep 2013
Location: Baraboo, Wisconsin
Posts: 143
Likes: 0
Received 1 Like on 1 Post
Default

Thanks John, and will do. I'm glad you mentioned the smaller increment for the spacing as I probably would have overdone it!

You've helped a lot already, but I've another question (perhaps others can chime in here): For a future project, I'm thinking of constructing an all-around control line handle featuring adjustments for line length and spacing. Is the all-around feature (as in 1/2A up to size .40-sized planes) too much to ask of one handle? I've seen some designs on-line, but don't want to embark on a fool's errand!

Thanks!

DaveyMo...
Old 10-20-2015, 06:11 AM
  #29  
gcb
 
Join Date: Oct 2002
Location: Port Ewen, NY
Posts: 3,440
Likes: 0
Received 4 Likes on 4 Posts
Default

Davey, a few things to try:

Check the balance (CG) and make sure the plane is not tail heavy.

Check that the wing and stab incidence are the same (probably 0 ).

Check the control movement. About 20 degrees should be good. Also make sure that the amount of up and down are the same.

Make sure that full up or full down are not transmitting excessive force to the elevator.

If you have too much elevator movement, as mentioned above move the lines closer at the handle.

Good luck!

George
Old 10-21-2015, 06:46 AM
  #30  
Thread Starter
 
Join Date: Sep 2013
Location: Baraboo, Wisconsin
Posts: 143
Likes: 0
Received 1 Like on 1 Post
Default

George:

Well-written and great advice. Thanks!

Davey Mo...
Old 10-22-2015, 05:40 AM
  #31  
 
Tom Nied's Avatar
 
Join Date: Feb 2002
Location: Queen Creek, Arizona
Posts: 2,232
Received 22 Likes on 21 Posts
Default

Or a further out hole on the control horn.,
Old 10-24-2015, 10:52 AM
  #32  
 
Join Date: May 2006
Location: Sierra Vista, AZ
Posts: 713
Likes: 0
Received 6 Likes on 5 Posts
Default

...To John B's explanation of PIO, it is worst where the pilot has tried to correct an unwanted response but gets out of phase.

He corrects too late - the pilot has to notice the deviation, then try a correction. That correction is often too large, and when the model eventually responds - (even a fraction of a second can make it too late to steer out of the deviation smoothly) - the correction overdoes it and goes too far the other way. You're back to the original situation, and it can continue to repeat as you try to catch up. The 'divergences' often get worse the harder you try. PIO isn't new.

Republic Aircraft's XP-56 "Black Bullet' (about 1944?) experimental offering to an ARMY Air Corps (pre-USAF) spec was a tailless, delta wing, pusher-prop design. On the initial takeoff attempt, the pilot got into PIO and crash that nearly killed him. The other two experimentals were the Curtiss(?) Ascender, pusher-prop, swept wing with small stabilator up front. The name is a pun: listen to it. The third was a twin boom pusher-prop of somewhat more conventional looking design.

Some modern jet designs, too, had such problems - early flights of some USAF or USN Fighter /or Attack planes with all-flying tails were shown, in newsreels, landing with the tails whipping up and down frantically, trying to find THE right position.

For us, it's "ONLY" a matter of breaking a model airplane...
(edited - phrasing)

Last edited by Lou Crane; 10-24-2015 at 11:04 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 Off
Pingbacks are Off
Refbacks are On


Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.