Showing posts with label Lewis Gun. Show all posts
Showing posts with label Lewis Gun. Show all posts

Sunday, January 19, 2020

Moved Lewis Gun Forward 3 inches


 While I've been waiting for better weather I fixed a problem I've had getting in and out of the cockpit.  I had remade the mount for the Lewis Gun to remove the clutter from the upper surface of the center section.  I thought it completely wiped out any lift in the center section, with all the tubes. 
Unfortunately I moved the gun back about 1 1/2" making it harder in my old age to get in and out of the cockpit.  I kept hitting my head on the gun. 
I remade the mounts to move the gun forward 3" and to shorten the rear handle about 1 1/2".  It's now very easy to get in and out.  You don't even notice the gun is there.


 I made longer rear mounting brackets to move the gun forward and still use the brackets in the center section.

 I moved the forward mount back along the barrel.  It made the clamp around the barrel a little more complicated but it works.  I had to re-bend the tall brackets slightly to make everything fit. 
I like the look better with more of the barrel sticking out past the mounting.

Saturday, May 7, 2016

Lewis Gun Mount on Center Section


 Some time after the plane flew with the biplane wings Dad built a fake Lewis gun and mounted it on the wing center section.  Rather than take the plane apart and uncover the center section he built a mount for it which could be bolted on to the assembled plane.  The tubes support the light weight gun.  The wires prevent the propwash pushing it back.  It works fine.


 I got to thinking that the tubes and wires are probably disturbing the air flow such that there is little or no lift from the center section.  As a result I decided that while I had the center section uncovered I'd make a different mount.  I have no interest in something as complicated as on the SE5 since the gun doesn't work.  I would like to make one that fires acetylene gas some day.

I decided to mount the gun to the spars with little "A" shaped mounts.  The forward mount picks up the old clamp around the barrel and the aft mount picks up the bolt hole in the gun, from the old mount.  As a result the idea is the same for both mounts but the forward mount is taller than the aft mount.

I bent the brackets with 30 degree and 60 degree bends.  to get the mount hole on each half the same height I made the hole in one, clamped them to the work bench, and punched the second hole.  Then the second can be cut to length and the end rounded like on the brace wire clips in the prior blog post.


The gun sets nice.  I made "L" shaped brackets for each side of the center rib.  They are riveted to a piece of aluminum using the rivets which hold the nut plates to the bottom of the supports.  The aluminum gives the brackets some stability and a place to attach the fabric covering.

The nut plates allow the mounts to be screwed on after covering.

The supports are the same, forward and aft, except the bend angle is slightly different because of the rib contour.


The supports are each bolted to the spar with a 3/16" bolt.  On the rear spar they go all the way through the trailing edge with a little counter bore so they don't show through the fabric covering.

For the forward spar 2 small holes were sawed into the aluminum leading edge to get to the nuts, and then covered with aluminum duct tap.

The finished mount should work fine and may even be slightly lighter, a nice bonus.