Home       Aeronca    Stinson                                                                                                               ... by John Baker

Stinson ELT Installation
This page created  4/10/99
Updated 6/6/99
Click on images for larger photo.

 

Installing an Emergency Locator Transmitter in the Stinson is not difficult and it is possible to complete an attractive installation without an external antenna.

Ameri-King AK-450 ELT Installation in Rich Tweedie's  108-2, N175C.
Notes and photos by Rich Tweedie

    "The Ameri-King was mounted with three D type clamps to the supplied mounting tray. It was mounted immediately behind the baggage compartment.  The antenna installation was complicated by the poor looks and excessive flexibility of supplied ELT antenna. The solution we have chosen is to mount the antenna horizontally inside the fabric.  It is mounted longitudinally, from the middle top of the fuselage bulkhead immediately aft of the baggage compartment, to the next bulkhead aft of that. To prevent the antenna from whipping around in the fuselage, I made a bracket for the antenna top to fit into at the rear bulkhead. It was fabricated from ¾ inch linen phenolic (Micarta) rod, with a hole for the antenna top to slide into, and drilled and tapped for an 8-32 screw at the other end.
    Concerned that there might be too much end plate effect (capacitive top hat loading) with the end of the antenna near the bulkhead and stringers, I ran an SWR test with an MFJ-259B meter. Results were a nearly perfect 1.1 to 1 Standing Wave Ratio."

ACK ELT Installation in NC6197M
Notes and photos by John Baker

I chose an ACK model E-01 ELT for my Stinson, and like Rich Tweedie, installed it behind the baggage compartment. Access to the ELT is gained by unsnapping the canvas flap on the back of the baggage compartment.  I located the ELT close to the fuselage centerline as advised by ACK, but was careful to offset it to stay clear of the elevator cables.  A birch ply "platform" is attached to the fuselage tubing with Adel clamps and the ELT aluminum ELT tray is mounted to that.  The annunciator for the ELT is located on a subpanel below the main instrument panel next to the intercom.  I have installed the antenna in the same location that Rich used, but  fabricated a different support for the antenna tip, since the ACK antenna is too short to reach aft to the next bulkhead.  I fabricated a small aluminum bracket that spans the two center stringers and holds a small plastic snap bushing from Aircraft Spruce to "trap" the antenna tip.  Photos of the antenna installation are below:

The photo on the left shows the ELT antenna installation, looking forward toward the baggage compartment.  The one on the right is looking aft.  The antenna is mounted on the former above the aft end of the baggage compartment and the tip is trapped by the bracket added between the stringers.  The upper stringer assembly is almost ready for priming with epoxy primer prior to final installation on the fuselage.

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