Oxygen bottle mount in RV-10

[fehdxl]

Thanks for the pictures.

I'm leaning towards something like this (not proportioned correctly):



Thinking I'll move it one bay aft, along the aircraft right side.

I'll attach the for/aft facing 3/4 x 3/4 angle to the stringers and the left/right facing angle to mount the brackets.

What do you all think? Strong enough? Not going to hurt anything?

P.S. Now that I think about it some more, I'd have to mount those brackets a bit higher else the bottle will hit the left/right angle... there's only about 1/4" clearance from the mounted surface with those brackets. Hmm....

Thanks!

-Jim

[Lan Vinh Do]

mine has been installed like this.

https://picasaweb.google.com/lh/phot...eat=directlink

lan vinh do

[Mike S]

Originally Posted by fehdxl

Thinking I'll move it one bay aft, along the aircraft right side.

What do you all think?

Thanks!

-Jim

Watch out for C/G issues, steel tanks are heavy

Alum/composite tank is a lot lighter, but still that is a long way back of the C/G.

[flion]

Originally Posted by Lan Vinh Do

mine has been installed like this.

https://picasaweb.google.com/lh/phot...eat=directlink

lan vinh do

Do you have some structure supporting the tank underneath? The spec sheet for the brackets show that there is very little G tolerance in that orientation.

Edit: Whups! My bad; I was remembering the 2-4G axis as lengthwise for some reason. So you only have to worry about fore/aft forces in your installation. Jim, I think your proposed installation will be fine. Indirect heating should not be that much greater there than a few inches lower in your original proposal. Just be sure it doesn't interfere with any dorsal antenna locations you may be planning on.

[fehdxl]

Thanks everyone for the ideas and inputs. After spending a couple hours with an -8A builder brainstorming different locations and orientations, I think I've almost convinced myself where to put it....here:



I don't believe it will interfere with anything; even though it's closer to the skin that will be warmer from the sun, there is about 3" of clearance there; and I'll be able slide it fore and aft (even aft of the bulkhead) a bit depending on how large the regulator is. I do still have to add triangle braces to strengthen it laterally.

We figured that the stress under 4 G's is the same at the top as the bottom. Probably 9 pounds there...so that's 36 pounds divided by two brackets--18 pounds each. The rivets that go through the skin will be in tension (not the best technique) so I'm going to put two rivets through laterally as well.

So what are your thoughts? Good? Bad? Ugly?

Thanks!

-Jim

[fehdxl]

BTW, here is the documentation showing the designed G forces in all three axis.

http://www.mhoxygen.com/attachments/132_CMKOhmega-1.pdf

-Jim

[DanH]

Originally Posted by fehdxl

BTW, here is the documentation showing the designed G forces in all three axis. http://www.mhoxygen.com/attachments/132_CMKOhmega-1.pdf
-Jim

Pro engineers....question please. 10G is easy enough, but what is the meaning of "@ 1G./125 ms. sin." ?


10 G. Down @ 1G./125 ms. sin.
9 G. Forward @ 1G./125 ms. sin.
2-4 G. Side to side @ 1G./50 ms. sin

[dpansier]

Originally Posted by fehdxl

Thanks everyone for the ideas and inputs. After spending a couple hours with an -8A builder brainstorming different locations and orientations, I think I've almost convinced myself where to put it....here:



I don't believe it will interfere with anything; even though it's closer to the skin that will be warmer from the sun, there is about 3" of clearance there; and I'll be able slide it fore and aft (even aft of the bulkhead) a bit depending on how large the regulator is. I do still have to add triangle braces to strengthen it laterally.

We figured that the stress under 4 G's is the same at the top as the bottom. Probably 9 pounds there...so that's 36 pounds divided by two brackets--18 pounds each. The rivets that go through the skin will be in tension (not the best technique) so I'm going to put two rivets through laterally as well.

So what are your thoughts? Good? Bad? Ugly?

Thanks!

-Jim

A few things to consider:
With any type of frontal impact the cylinder could break loose from the mount and only have the back of your head to slow it down.
Mounting it down low places the seat backs and some metal between you and the cylinder dissipating some of the energy should it come forward.

[krw5927]

Originally Posted by DanH

Pro engineers....question please. 10G is easy enough, but what is the meaning of "@ 1G./125 ms. sin." ?


10 G. Down @ 1G./125 ms. sin.
9 G. Forward @ 1G./125 ms. sin.
2-4 G. Side to side @ 1G./50 ms. sin

Dan, that's a vibration design/test limit. A constant 10G is one thing, but a fast sinusoidal (sin.) vibration from 0-10G is quite another. It's saying if you're going to subject the O2 bottle to a 10G downward acceleration, you better take at least 1.25 seconds to get there, starting from zero (actually you're starting from 1G down in level flight, but that's in the details). Not gonna happen in our planes when you think about it in terms of pushing the stick around, but vibrations throughout the airplane structure complicate matters a bit. Still though, without some accelerometers mounted to the airplane in flight, and in that particular location, there's no way for us amateur builders to know what's really happening. That would have to be one heck of a vibration though, not sure the airplane would survive it...

The only analogy I can come up with off the top of my head (and admittedly not a very good analogy at that) is an impact driver. A small constant force will not get those lug nuts on your car wheels to budge. Alternate between applying that same force and applying zero force every few seconds, still nothing. Start applying that same force in a quickly-repeating manner and suddenly the lug nuts break free.

[flion]

It's been said before but I'll say it again: this forum is amazing. No matter what the question, it seems someone has the answer. I learn so much here. Maybe we should call this 'RVU'.