As far as the rear mounts go- I was thinking of having a cross
brace from the upper left firwall attach point to the upper
right engine mount point. I can't fit one going from the upper
right firewall attach point to the upper left engine mount
point- it interfers with the water pump belt. I can't( or
shouldn't) have a cross tube going from the upper right firewall
attached to the tube that goes from the upper left firewall to
the upper left engine mount, about the midway point in the upper
left tube, correct?(Anyone follow that?)
The upper right engine mount bracket is pretty close to what
Mike Wills is using, but he has lightening holes in his. I made
mine and then saw that it was just about identical to his.
The distance from the firewall to the water pump housing is 14"-
so firewall to prop flange should be 44".
So Paul, I think I'll take your advise and cross brace the upper
mount points. Any more input is apprciated. Brian Trubee
Redmond,Wa
Brian,
Is this the distance to the water pump housing or the pump shaft
flange? My 10" measurement is to the face of the water pump shaft
flange. If you are 14" out, your CG should still work out. I was
amazed at how far forward the engine could be moved and still stay
in the CG range. I have attached the results of my calcs.
Ken P.
Here are the results of my CG calcs. These assume a 110 lb pilot,
no fuel and 35 lbs of baggage. This should be the worst case
scenario for a RV-4. The calcs are based on the CG of the engine,
not the location of the prop flange.
2" forward - 70.63
4" forward - 70.11
5" forward - 69.85
6" forward - 69.59
7" forward - 69.33
8" forward - 69.08
9" forward - 68.81
Note that the allowable range is 68.7 to 77.4, and with the Lycoming
the CG was at 71.18. The CG of my engine is 4" forward of the
Lycoming.
Ken Powell
You are a tiny guy Ken. You sure looked heavier than 110 pounds the
last time I saw you :-)>
Paul Lamar
Paul,
Yeah, I weigh just a little more than 110 lbs (try 180). I just used the 110 lbs as a
worst case. However, my wife and youngest daughter weigh between 110 lbs and
120 lbs and who knows, maybe I'll get lucky and one of them will decide to fly
someday (but I'm not holding my breath). Thankfully, my oldest daughter really
likes to fly and she is 130 lbs so the W & B does have some personal relationship.
Anyway, I hope that she will eventually get her PPL and fly a lot with me (she is 21
and graduates in May with a MIS degree, another big relief for Dad!).
Boy, I can see that my girls will kill me if they read this message!
Ken Powell
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