Trimming Question

[Dean Pappas]

Hello Larry,
You should not be trying to trim out the pitch behavior with rudder in level flight, but in the knife edge and/or vertical down. Tail-heaviness makes planes pull to the belly both there and in level flight with rudder. You just might be tail-heavy, based on your statement that you have to make the looping portion of the 1/2 reverse cuban start. You are probably in the very smal adjstments needed neighborhood. Unless your horsepower is spectacular (it should with the combo you have) a normal plane will want to start to at least think of dropping its nose after the 1/2 roll on the 45 up.
 
Check both knife edges and the up and down lines. If three out of four (it's not a vote) pull to the belly, then you are tail-heavy.
Regards,
    Dean Pappas

-----Original Message-----
From: Larry Diamond [mailto:ldiamon at kimball.com]
Sent: Thursday, May 01, 2003 10:13 AM
To: NSRCA
Subject: Trimming Question



I am sorting out an H9 Aresti 40 that I intend to start with Sportsman until I get another plane sorted out. 

CG appears to be very close. It holds a 45 degree upline straight and needs a touch of elevator to start the pull through the 1/2 Reverse Cuban 8. Inverted flight only requires a touch of down elevator.

My tank location was modified from the intended location and is on CG, to be read, "The front of the fuel tank is about 1/4 inch forward of the leading edge. I have mounted a YS 63 and has unlimited vertical after 4 tanks of fuel. CG is currently located at 4" back from the LE per the instructions (aft range). This tank location result in outstanding ground handling on grass. Zero tendency to nose over, not even close...

The problem is in level flight it pitches to the belly with rudder input. Made for an interesting landing when I corrected with a touch of rudder for cross wind. 

Is this an incidence problem? I haven't tried a power off dive yet to check it out due to time. What else could I look for?

Engine - YS 63 New (2 tanks for break in and 4 flights) 
Prop - APC 11x8 
Max RPM - 11,400 (slightly rich still) 

Thanks, 

Larry K. Diamond 
Program Manager, KEG 

Phone:  (812) 634-4286 
Pager:   (877) 575-4163 
Fax:      (812) 634-4007 
E-Mail:  ldiamon at kimball.com 

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