News:



  • July 05, 2025, 04:44:43 PM

Login with username, password and session length

Author Topic: Line III  (Read 1880 times)

Offline RC Storick

  • Forum owner
  • Administrator
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12567
  • The finish starts with the first piece of wood cut
    • Stunt Hangar
Line III
« on: November 15, 2006, 03:36:05 PM »
Line III now available from Stunt Hangar download section or at this link

http://www.stunthanger.com/temp/LineIIISetup.exe
AMA 12366

Offline Bill Gruby

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1488
Re: Line III
« Reply #1 on: November 15, 2006, 05:14:00 PM »
Robert;

Without sounding to illiterate, what pray tell is "Line III". Is it something that I really need?

I know in this computer age it's difficult, but in giving your reply could you keep it kind of simple. I'm still trying to get to level  2 with this thing.

Bill Gruby n~ n~ n~
Bill Gruby
AMA 94433
MECA 5393-10

Offline RC Storick

  • Forum owner
  • Administrator
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12567
  • The finish starts with the first piece of wood cut
    • Stunt Hangar
Re: Line III
« Reply #2 on: November 15, 2006, 06:31:12 PM »
Line III will help you set your initial line rake for bench trimming.
AMA 12366

Offline Bill Gruby

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1488
Re: Line III
« Reply #3 on: November 15, 2006, 06:50:44 PM »


Thanks Robert--------Sounds simple enough--------Will take a peek.


Bill Gruby y1 y1 y1 y1 y1 y1
Bill Gruby
AMA 94433
MECA 5393-10

Offline Bill Smith

  • 21 supporter
  • Trade Count: (0)
  • Commander
  • *
  • Posts: 256
Re: Line III
« Reply #4 on: July 15, 2008, 07:55:50 PM »
Thank You
 
 Tried it and compared it to two planes that I think are setup right and they are a close match. So from now on I will use this for the initial setups and save myself some guessing.

Offline Bob Disharoon

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 448
Re: Line III
« Reply #5 on: July 16, 2008, 01:34:14 PM »
Robert;

Without sounding to illiterate, what pray tell is "Line III". Is it something that I really need?

I know in this computer age it's difficult, but in giving your reply could you keep it kind of simple. I'm still trying to get to level  2 with this thing.

Bill Gruby n~ n~ n~


"BG.".I can't believe you actually said that.Is there anything YOU really don't need ?H^^....lol..."HD"

Offline Peter Germann

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 403
Re: Line III
« Reply #6 on: July 23, 2008, 02:57:41 AM »
Line III will help you set your initial line rake for bench trimming.

Related to LineIII, two questions I wish to clarify are:

1.) On may latest airplane the location of the C.G. varies approx. 1/2 in between full and zero fuel. IF, as I assume, LineIII's "Leadout position behind C.G."  is calculated from on the in-flight C.G. (with fuel), is it correct to use 3/4 fuel load when defining the airplane weight and the location of its C.G.?

2.) With LineIII giving the leadout position for level flight (with 3/4 fuel on board), what can I do to get the proper leadout position when flying overhead through the top of circle with only 1/4 fuel left?

rgds  Peter Germann

Peter Germann

Offline Bob Reeves

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3414
    • Somethin'Xtra Inc.
Re: Line III
« Reply #7 on: July 23, 2008, 11:04:01 AM »
Hi Peter,

The best person to answer your questions would be Pete Soule but he doesn't hang out here. My answer is to do what everyone else does, use LineIII for a starting point and fine tune from there.

Offline Peter Germann

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 403
Re: Line III
« Reply #8 on: July 24, 2008, 06:13:27 AM »
Hi Peter,

The best person to answer your questions would be Pete Soule but he doesn't hang out here. My answer is to do what everyone else does, use LineIII for a starting point and fine tune from there.

Thanks, Bob.
Trying to simulate the overhead situation, what I did was playing with input numbers (airplane weigth) until Line III returned a line pull figure being equal to the line pull in level flight minus the weight of the airplane. (-1G) Resulting was a leadout position approx. 1/2 in rearward from the number for level flight. Assuming that this setup leads to accurate tangency of the fuselage when flying through the top of the circle, I would hope to prevent drag caused by yaw in a place where I cannot afford to have it. Yes, I do realize that a line leadout position "optimized" for overhead flying will lead to a bit of yaw to the outside in level flight, but I believe this is a trade-off I can accept in exchange against better line tension where it counts more...
Considering the substantial difference of leadout positions between "level flight with full fuel" and "overhead  flight with min. fuel" I would really like to know whether my assumptions are correct. When you are mentioning Pete Soule, does this mean he is the author of LineIII?
Peter Germann

Offline Bob Reeves

  • 2016 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3414
    • Somethin'Xtra Inc.
Re: Line III
« Reply #9 on: July 24, 2008, 09:09:04 AM »
Pete was the brains behind the math, I put a user interface on his work and out came LineIII. The LineIII download should have included a couple pdf files written by Pete that go deep into the mechanics of his work.

Never really thought about the overhead situtation but what you are saying sorta makes sense. The only issue that comes to mind is that we typically start moving the leadouts forward if we have overhead line tension problems. Maybe someone that really understands this stuff will chime in. Sure is a great question...

Offline Mark Scarborough

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 5918
Re: Line III
« Reply #10 on: July 24, 2008, 01:05:21 PM »
what Bob says is true, typically to enhance overhead line tension (all other things being trimmed close) you move the leadouts forward, which decreases the speed you scrub off overhead, the speed is what maintains line tension overhead more than anything else. a couple other things to think about, I have had problems with fuel feed if the airframe is yawed out to much, I am talking moving the leadouts less than a 1/4". had it quit in the clover, ie low speed and corner g forces. Before comments are made, my tanks have a offset in them so the pickup is outboard to begin with. The other issue that would concern me is the yaw introduced in square manuevers by having the leadouts trimmed intentionally "off" normal position.
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Offline phil c

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2480
Re: Line III
« Reply #11 on: July 24, 2008, 01:46:31 PM »
As somebody said someplace else, the calculation is a tentative place to start, not an unchangeable design feature.  Set the initial position via Line III and then trim as necessary.  I believe most people find themselves moving the leadouts forward for better overhead tension, once they fly the plane, but it all depends on how the thrustline, balance point, wing offset(if any), rudder offset, and other little vagaries balance out in the air.
phil Cartier

Offline FLOYD CARTER

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 4503
    • owner
Re: Line III
« Reply #12 on: July 24, 2008, 03:46:44 PM »
What Bob Reeves said, and the usual practice of having the lines exit about 3/4" behind the CG is really all you need to know.  The smart trick is installing an adjustable leadout gadget.  It only takes a couple flights to get the leadouts in exactly the right place.

I know some people spend a lot of time writing some computer programs for a procedure which is so very easy to zero-in, with only a flight or two.

Floyd in OR
91 years, but still going
AMA #796  SAM #188  LSF #020


Advertise Here
Tags: