Sideways engine?

[ORLANDO FRETS]

Don't forget the engine is rotating. A one cylinder engine is not balanced. Throw the firing cycles and what do we have????????


ORLANDO FRETS
ojfrets at earthlink.net



----- Original Message ----- 
From: george kennie 
To: discussion at nsrca.org
Sent: 1/15/2004 5:27:45 PM 
Subject: Re: Sideways engine?


Just a little additional input here. This off-set to the left thing doesn't seem to me to be as pronounced as many seem to be implying. My Hyde type mount is 1/2"off center on the firewall, but the buggar is almost  an inch thick and the engine doesn't sit up against the puck to allow line clearance, so at that distance from the firewall the off-center distance is less than 3/8" which puts almost 2&3/4" of the shaft to the right of center. Now I grant you that the segment to the left of center is heavier, but by how much? The whole shaft weighs 5.6 ounces.If we say that 3/4 of the weight is to the left of center, then there is 4.2 ounces left of center and 1.4 oz. to the right of center.Don't forget that this monster has a spinner and a prop bolted to it's long end and they total somewhere in the neighborhood of 7 ounces. Let' see now 7 plus 1.4 equals 8.4 ounces right of center and 4.2 ounces left of center.Hmmm,....Oh yeah, lets not forget that there's a header contributing to the picture also. Its hanging off  the left side of  the aircraft and it weighs 1.2 ounces, so now we have 5.4 on the left and 8.4 on the right, so we've narrowed it down to only a 3 ounce differential.Now I really don't know if it affects our execution of snaps or tight high-G corners, but I think that the  aircraft  is still in a state of dynamic imbalance. I think that I can come awfully close by statically balancing, but is it perfect? I don't think it's even close.And I also think that if you could fly an aircraft that was in perfect dynamic balance, you would really be able to tell the difference and it wouldn't take someone with the ability of a Troy to be overwhelmed with awe. 
I remember when setting up my first Heli that the instructions emphasized balancing the blades, and they didn't want you to just hook up the blades to the blade holders and the shaft and balance the whole thing as a unit, but the individual blades were to be balanced against each other to be absolutely certain that the balance point was at exactly the same distance out on each blade. Otherwise the dynamics would be off, even though the head, as a unit, was in balance. 
Just a little more grist for the mill. 
Georgie 
Bob Pastorello wrote: 
Nat, I'd tend to agree - the moment arm of the mass offset is so minimally-different from a conventional inverted motor.  Actually, some mass moment would actually move CLOSER to longitudinal centerline with a side-mounted motor, thus reducing the dynamic imbalance.  As someone else pointed out, we statically-balance with a mass offset left of center.    How little difference could there actually be?    Maybe tenths of an ounce in moment?  
Bob Pastorello, Oklahoma 
NSRCA 199, AMA 46373 
rcaerobob at cox.net 
www.rcaerobats.net   
----- Original Message -----
From: Nat Penton
To: discussion at nsrca.org
Sent: Wednesday, January 14, 2004 9:02 PM
Subject: Re: Sideways engine?
 If lateral balance is attained with assymetric weight distribution then the plane would be dynamically unbalanced, that is there would be assymetric forces during accelerated roll . I suppose this might be noticeable with significant assymetric weight distribution, but probably not with what we are talking about. Mike Nauman where are you ?
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