RV-6 Tailwheel Measurement

Anyone have plans or an RV6 handy?

I reweighed my 6 but I used the Tailwheel this time instead of the socket where the tail spring bolts in (first time I did this I had it sitting on a post at the socket.)

So, I need the distance from the socket to the axel of the Tailwheel. And/or the typical arm of the Tailwheel. Actually, I wonder how much variation there is between builders of the Tailwheel arm? What would cause a variation of the Tailwheel arm from one builder to the next if the plans were followed? Hum?

I wanted to plug in the new numbers but without that difference I don't know the new arm for the Tailwheel.

Jim

With my Bell fork it is 20". However, that is not the Arm. You would need to measure perpendicular to the datum line and the tail spring is not when measured along its length. The Tailwheel Arm is 236.75 from datum.
Since the tail spring socket isn't a known reference to datum, all you could do is estimate without re weighing.

For me and anyone following along,

Is there a problem with dropping a plumb bob down from the socket and measuring that distance? And, do I actually need to weigh it again? Wouldn't it be okay to simply put the tail back up to level and drop the plumb bob from the tail wheel and measure that? (I guess if I knew the angle created by raising the tail to level for weighing, I could use geometry to find the arm from the measurement you gave me.)

Not trying to be difficult, I just know half the time I end up saying "oh, ya, now it makes sense..." And I understand the actual length from the socket to the wheel axel would be slightly different from the line on the hanger floor from the two points defined from a plumb line off those two spots.

Thanks for the post!

Jim

Ok Jim, I am just trying to follow along here. I take it you only re-weighed the tail.? Otherwise you would have what you need to redo your W&B. Confused....

No, I weighed the mains and tail all at the same time with three digital scales while it was level (tail up in flying attitude).

The problem I ran into was when I did this the first time before the first flight 8 years ago, I used the socket and not the Tailwheel location for the aft point.

What I forgot to do this time was drop a plumb bob down from the tail to find the arm for the Tailwheel versus the socket.

As I scrounge the internet I find the published arm for the Tailwheel in the old original construction document. But, on vans website under the downloads for rv6 W&B that form they actually do NOT show arms, which I suspect they changed to reflect the fact that they can't seem to get most of us home builders to follow the plans.

I think the reason I made the initial post was that I didn't realize I was going to find a published number for Tailwheel arm.

I'm using 236.9 for tonight and tomorrow at the hanger I will confirm that on my airplane with the tail up. I still have all my marks on the floor from the first W&B.

Well, this is dragging on, I hope someone besides me will get something out of my rambling.

If you got this far, thanks!

Jim

Jimd said:

...As I scrounge the internet I find the published arm for the Tailwheel in the old original construction document. But, on vans website under the downloads for rv6 W&B that form they actually do NOT show arms, which I suspect they changed to reflect the fact that they can't seem to get most of us home builders to follow the plans. ...

Click to expand...

It wouldn't have occurred to me to look for a published arm. I think that is for reasons other than not following the plans. For instance, my airplane was supplied with a tailwheel spring that was bent down at the end and a non-swiveling tail wheel. During the build, the swiveling tailwheel became available and I thought that was a much better choice so I had to cut off the spring and machine down the end to a smaller diameter. My arm for the tailwheel may be unique in the world as may many other builders tailwheel arms.

I wasn't trying to not follow plans, I was just trying to keep up with modern improvements.

My tailwheel is at 236” aft of datum.

Nothing wrong with leveling the aircraft again and measuring the arms, it doesn't have to be on the scales to do that.

I would suggest you just re-measure all the arms using the wing LE as your reference instead of just from the socket to the wheel.