Excelleron Trim and CG

[Dean Pappas]

Oh yeah! Sorry 'bout the omission, Pete.
 
I added two washers (about 0.040" ) between the hardwood beams and the front posts on the soft mount.
That works out to another degree of down thrust, compared to stock.
The right thrust is at 3 degrees ( 3/4" difference in tailpost distances across the 15" prop) because any more made the plane dog-track.
Some right rudder trim was added, and it's a good compromise.
I am anxious to try the throttle/rudder couple: planes with real big chins tend to suffer from the "there is no correct amount of right thrust" syndrome.
I am still cutting back on control throws ... a whole bunch. I think that the high rate elevator will end up at 22 degrees, and the ailerons are at about 15 and are still faster than needed.
The rudder is at 35 degrees.
 
 

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Pete Cosky
Sent: Wednesday, February 02, 2005 10:25 AM
To: discussion at nsrca.org
Subject: Re: Excelleron Trim and CG


Dean,
 
Thanks for the info. It will be a big help as I finish up my Excelleron. 
 
I do have a couple questions though:
 
What right and down thrust do you have dialed in?
 
Are your incidence measurements using the stab at "0" and then measuring the wing?
 
Did you use the manufacturers suggested throws on the control surfaces?
 
BTW - Thanks for all the info.
 
Pete Cosky

----- Original Message ----- 
From: Dean  <mailto:d.pappas at kodeos.com> Pappas 
To: discussion at nsrca.org 
Sent: Wednesday, February 02, 2005 9:43
Subject: RE: Excelleron Trim and CG

Hi Nat, and Hi Terry,
My Excelleron weighs spot on 9 pounds with the Magnum 120 AR and 15-10.
The CG is at 7-1/16" and the total incidence (with the 1/16" positive I added) is 3/32" as compared to the stab.
The plane carried UP elevator trim, until I added the incidence, and the CG had to be about 7-1/4" back to almost get rid of the trim.
I didn't like how the airplane flew, there: it was just marginally tail-heavy and the "lock" in wind suffered.
The plane also hinted at climbing out of a 45 climb or dive.
The snaps are lovely, and high rate elevator will still cause the plane to "bury" in the snap, so it ain't nose-heavy.
The vertical UP line is straight, and the DOWN line only pulls to the canopy after a full 4 Mississippi count.
That's plenty good for anything in the schedule.
The knife edges are dead straight, and there are no electronics used. That was part of my review criteria: entry-level with non-fancy radios.
The plane knife edge loops beautifully, and when you wail on the rudder in the last 1/4 loop, it does proverse roll a small bit,
but this doesn't show at the kind of rudder throw necessary for point rolls.
I think this is the easiest knife edge looping ship I've had my hands on.
I am contemplating pushing the CG even farther forward, to see if I can get it to trim properly.
I think a beginner will benefit from a freight train ... I mean slightly nose-heavy plane.
Regards,
    Dean
 

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