Well, the dimensions I thought would be easy to get aren't.

For starters, the horizontal component of the thrust line is not
specified. The vertical is. It appears to be 5.5 in. below the top of
the longeron. See drawing 17a. I have looked at all the drawings and
this appears to be the only one the thrust line is shown on.

I measured the mounting points on the "as built" firewall. There are six
hard points. The four corners are easy to locate because there are
tooling holes (1/4") there. The two low center ones that support the
nose gear are more difficult because no dimensions are given. From
drawing 46A it appears that they are close to the intersection of
F-601N(L/R) and F-601D(L/R) stiffeners. The note there says "DRILL IN
ASSEMBLY WITH ENGINE MOUNT (2 PLACES)"  My best guess as to the
locations are shown on the sketch. Notice that they are asymmetrical,
i.e., they are 1/8" closer to the left side of the fuse. This sketch is
looking at the firewall from the spinners point of view, i.e., left is
right etc. Since the thrust line is only half specified it is impossible
to locate the points relative to the thrust line, so all dimensions are
relative only to each other.

To make matters worse, I can find no specification or drawing showing
the distance from the prop flange to the firewall.

This is an unsatisfactory situation.

I will contact Van's to see if I can get the "official" specifications.

I am attaching scans of drawings 17A, 19 and 46A and my crude sketch.
You might notice that drawing 46A bears the title "ENGINE/NOSE GEAR
MOUNT"  and below that "RV-6A, 7A, 9A." Apparently one mount would fit
all three airplanes.

Will let you know as soon as I hear from Vans.

Hope your day went better than mine :-)

Doc

Doc can you borrow a mount from Van's ?
The attachments did not make it here.


Paul Lamar

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