A friend has a Piper Cherokee (four place) made in 1964. He is in the brown jacket. I am wearing the blue jacket.
(Many of the photos in this Instructable are from Google Images. I do not have access to the airport and to his airplane. During this project we did not have a lot of time for making photos.)
Step 1: His New GPS
He also has a new GPS unit for his airplane. It is quite large compared to a GPS for an automobile--almost 6 inches across.
Step 2: Cherokee Cockpit and Instrument Panel
This is a newer Cherokee cockpit and instrument panel. It is already rather crowded. Finding a place for a large GPS and still maintaining good visibility is not easy.
Step 3: The Factory Mount
Garmin provides an attachment for mounting the GPS on the pilot's yoke. My friend wants his mounted on the top of the instrument panel. Sometimes he has me fly the plane while he attends to other things. Mounted at the top center of the instrument panel, the GPS is visible to both of us and I can check to make certain we remain on course.
Step 4: Hand Hold
My friend's Cherokee has a Hand Hold to give the pilot some leverage for pulling himself in an out of the airplane. It is a piece of extruded aluminum 3.5 inches long. It mounts to the top of the instrument panel with two screws.
Step 5: Location of the Hand Hold
In my friend's airplane, the Hand Hold is located where you see the yellow box. It is just forward of the rounded black plastic edge of the instrument panel that surrounds the instruments. My friend's airplane does not have a compass mounted on the windscreen brace, as in this graphic.
Step 6: Make a Paper Pattern
My friend and I were returning from a Sunday afternoon church service I conduct 100 miles away one Sunday a month when we began talking about a good mount for his GPS. I needed some angles and dimensions, so, after we landed, I made a paper pattern on the only thing I had available, which was some of the pages from the Sunday church bulletin.
The blue line highlights the edge of the paper. The green arrow points to the location of the mounting screws for the Hand Hold. The pen line at 27 degrees marks the angle of the window brace off of the instrument panel's top surface.
Step 7: How to Mount the Mount
The space between the windscreen and the top of the instrument panel does not allow room for a drill to make holes for a mount. I decided to use the existing Hand Hold device as part of the mount. In addition, I would not need to remove it from the airplane for my friend to store indefinitely in a safe place. If I did it might become lost by the time my friend eventually sells the airplane after he no longer flies. I did remove the Hand Hold so I could fit it on my workbench.
This is a view of the Hand Hold from its end. Notice the rounded top edge. I used a caliper to determine its diameter and matched it to one of my drill bits.
Step 8: A Piece of Pine
I chose a piece of 3/4 inch pine 1 1/4 inches wide and about 4 to 5 inches long. About 1/2 inch from the end I held the Hand Hold over the wood and marked the center for the rounded edge at the top of the Hand Hold. I drilled a hole that is just a little on the small side for a firm fit.
Step 9: Cut a Slot for the Hand Hold
The Hand Hold will slide into an opening cut for its profile. I marked the wood with a square to match the end view of the Hand Hold and cut a slot with my bandsaw.
Step 10: Trim the Slot for Rounded Areas
The actual extruded Hand Hold has some rounded areas in the corners. I expanded the slot where you see the yellow arrows to accommodate the rounded areas on the extrusion.
Step 11: Trim for the Window Brace Angle
I used my paper pattern to trim the end of the wood at 27 degrees to match the angle of the window brace. The wood will rest under the window brace so it will not pivot or move from the weight of the GPS when the mount is finished.
Step 12: Slide the Hand Hold Into the Slot
This graphic shows the Hand Hold inserted into the slot cut for it. The fit should be a little on the tight side, but not so tight that you cannot move the Hand Hold without a hammer. Paint the wood any color that suits you.
Step 13: Add Sheet Metal
Add a piece of sheet metal about 3 inches wide and 6 inches long. It can be aluminum or steel. Attach it with screws as shown. Put the Hand Hold back into the airplane and screw it down.
You are now ready to use double stick foam to mount the GPS base to the sheet metal. One corner is clipped in the graphic because I did not allow enough room when making the graphic. Run the GPS cable from a power source. Snap the GPS into its base. Connect the power cable and you are ready to fly.
Step 14: The GPS Mounted
This photo was taken while the plane is still in the hangar. The GPS is mounted and ready to fly. You can see how the piece of pine rests under and against the window brace. Under one corner of the sheet metal you can also see the end of the Hand Hold. The GPS rests in a space that is almost made for it. It is visible for both seats, no matter who is flying. That is not possible with a mount on the pilot's yoke. Being close to the plexiglass, the GPS's antenna also has good access to all available satellites. The mount is plenty sturdy, too.