Purpose

This is a blog containing the build history of an experimental home built airplane. The RV-7A is a two place, piston powered, low wing, tractor configuration, tricycle gear, aluminum and composite aircraft. The original purpose of this blog was to document the construction of my experimental category aircraft in order to satisfy the build log requirement for the FAA. Now it's just for the amusement of friends and family as I document some of our aviation experiences. For more information on the RV series of aircraft see www.vansaircraft.com.

Monday, June 9, 2014

Step 11.8, Canopy strut mounts and map box

To lift the tip up canopy, gas struts are employed.  These gas struts are of the same variety as are used in automobiles although they are not nearly as strong as what might be found lifting the hatchback on a PT Cruiser.  The difference, of course, is the difference in the mass of the light weight airplane component and the much more sturdily built automobile hatch back.  Fortunately, airplanes don't have to survive a 5 MPH impact in any direction except through the landing gear.

It occurs to me that another reason for having the gas struts is that they provide a lifting force that is balanced on either side.  Since the canopy is a bit wobbly even with the aluminum frame, it probably really helps to lift from both sides.  Enough with the theory, on to the construction.  Here are the raw materials: The struts and some aluminum bar stock.  I've already laid out the cut line and drill locations.


First thing is to drill the holes while the pieces are large enough to clamp in the drill press.


I cut the bar stock and start tapping the holes for the 3/8" strut bolts.


That wasn't so bad.  After a little time on the Scotch-brite wheel and some counter sinking, here are all of the pieces ready for assembly on the canopy rail.


The next project is the map box.  First, a hole is cut in the bulkhead behind the panel because the map box is longer than the area behind the panel.



Then stiffeners are added to reinforce the bulkhead around the hole.


Now we rivet the map box itself together.  Unfortunately, I failed to take any pictures of the assembly of the map box, but here it is ready to go, sans door.


And from the rear:


Van's wants the box to be attached to the panel, but I don't think so.  There would be no way to remove the panel if at the same time, the map box door is also attached to the fuselage.  Clearly it's an untenable situation, so I used screws on the door instead of rivets.  


And finally, the map box and canopy struts in action :)


Next time we glue the canopy to the frame.

No comments:

Post a Comment