Long Nose, Forward CG, Aft leadout position - why

[Ken Culbertson]

This is one that has been thrown around before and I read all I could find, but my question is not the how, which there is plenty written here but the why.  The long nose forward CG and aft leadout position that is being used by some of our top fliers.  Are the three linked?   My latest ship displays some unusual antics on the tops of squares, both inside and outside.  It is not dramatic, just irritating and momentum robbing.  I am wondering if the lines whipping may be causing it.  Right now I have a rather forward leadout position.  1/2" behind the CG.  I am going to try a huge jump to about 2" to see what happens.  THe reason for seeking input is that I have a new ship on the "bench" (my office desk) and giving it the capability to have such an aft position requires changes to the inboard wing that simply can't be made later.

Thanks for any input - Ken

[Istvan Travnik]

Dear Ken,
The common sense is to direct 3° backwards from the CG, to the mid point of the leadout. (It is very simple to count, because sin and tg3° is right .05 or in other words: 5%, or 1/20.
Naturally this is a good measure, when you use your fullsize plane on fullsize line with 0.015" dia lines.
Ifyou feel yourself being enforced to use .018 lines, maybe this 3° can be not enough, try more (maybe 4°), as default. 
(I am so uncertain, because we in Europe practically never used .018 lines)
Istvan

[Mike Alimov]

Istvan - you should really try the 0.018" lines; after that the 0.015" lines will feel like rubber bands...

Ken - maybe the aforementioned top fliers could explain the "why", because there must be some other "secret sauce" here that everyone else is missing.  We've tried the forward CG + extreme leadout sweep combination and (predictably) got the same effects as one would expect from a plane flying in a very crabbed attitude (right yaw), i.e. weird stuff in corners etc.  Ended up coming back to normal CG (say, 25%) and normal sweep (about 1" behind CG for 0.018" lines). 
My question back to you - how does one find a job where an office desk becomes a building bench?  :-)

[Ken Culbertson]

Istvan - you should really try the 0.018" lines; after that the 0.015" lines will feel like rubber bands...

Ken - maybe the aforementioned top fliers could explain the "why", because there must be some other "secret sauce" here that everyone else is missing.  We've tried the forward CG + extreme leadout sweep combination and (predictably) got the same effects as one would expect from a plane flying in a very crabbed attitude (right yaw), i.e. weird stuff in corners etc.  Ended up coming back to normal CG (say, 25%) and normal sweep (about 1" behind CG for 0.018" lines). 
My question back to you - how does one find a job where an office desk becomes a building bench?  :-)

#1 That is precisely why I am asking the "Why" question.

#2 Your shop burns down and you own the company!

Ken

[Motorman]

Why? because it's all disinformation.

[Istvan Travnik]

Mike,
Briefly: tried but not loved...
In details:
-my models never exceeded 1800 grams (63.5 ozs)
-I never fly faster than 5.3 ÷ 5.4 sec/laps
-my fist is really not a Hercules-like...
Furthermore, I never felt the control being unprecise, since I use my exponential elevator mechanism for almost 40 years.  (It is 2-3 times slower around the "0" related to the end position.