The International Cessna^® 170 Association

Just came across this Youtube video showing how to get a Lionel horn to work. The 170 stall warning horn is exactly the same though slightly smaller. I haven't found a Lionel horn that would fit in a stall warning inclosure.

https://youtu.be/3LsDKsNBBKQ?si=YWUjUI6SedInyAVH

An avionics tech commenting on Mooneyspace.com recommended the Mallory Sonalert SC628 buzzer as a replacement.

While the Mallory SonAlert may cause an iA to “pass’ an inpsection…. it will NOT be heard in-flight due to it’s diminutive volume.

I have some experience with Mallory SonAlerts and they may fool an IA during inpsection whle it’s sitting and being tested in the hangar….but it will not likely be loud enough to be reliably heard in-flight except perhaps in a power-off stall and no headsets.

GAHorn wrote: ↑Thu Jan 11, 2024 11:46 pm I have some experience with Mallory SonAlerts and they may fool an IA during inpsection whle it’s sitting and being tested in the hangar….but it will not likely be loud enough to be reliably heard in-flight except perhaps in a power-off stall and no headsets.

George, I wonder if the Mallory SonAlerts install you are familiar with was installed inside a Bakelite enclosure? If so, I wonder if it might be an acceptable alternative installed in the open behind the instrument panel.

Bruce Fenstermacher wrote: ↑Fri Jan 12, 2024 1:45 pm

GAHorn wrote: ↑Thu Jan 11, 2024 11:46 pm I have some experience with Mallory SonAlerts and they may fool an IA during inpsection whle it’s sitting and being tested in the hangar….but it will not likely be loud enough to be reliably heard in-flight except perhaps in a power-off stall and no headsets.

George, I wonder if the Mallory SonAlerts install you are familiar with was installed inside a Bakelite enclosure? If so, I wonder if it might be an acceptable alternative installed in the open behind the instrument panel.

That may be a good alternative. I don’t know what the route toward approval might be to substitute that for the original….. If I were the authority…. I’d approve it based upon a Sound Level Meter comparison. **

Frankly, I’m surprised that FAA hasn’t required audible warning systems such as stall horns to be incorporated into headset-audio-systems, as a prerequisite to use of headsets…. just as they did with larger/transport-category and more modern aircraft. (but don’t let anyone over at FSDO read this comment.).

** I actually installed a SonAlert in the panel of my tractor to warn me I’ve set the parking-brake. It’s annoyingly loud in the open-air….but it’s an “intermittent-beeper” type. After leaving the parking brake applied with the engine idling one day….and then driving the tractor for almost a mile with the brakes applied…(it’s a 50 hp Kubota which easily masks the brakes)… I added a flashing Warning-Lamp system to remind me when I’ve set the brakes. This lovely solution…. doesn’t work if the steering wheel spokes hide the lamp….so after repeating the experience, I also added a SonAlert…which is astoundingly loud and obnoxious…. so I learned to turn the key “off” while the engine is deliberately left idling while disembarked. It’s a diesel so the engine keeps running….but the electrical system is dead thereby killing all warning lamps and the SonAlert. Thusly, I’ve managed to complicate my life by adding TWO warning systems which I can ignore.

I suppose we'd have to dig up the reg in CAR3 that required an audible stall warning and see what sound requirements, if any are there. If any a test would have to be conducted by the installer to show the piezo horn met the requirements. Otherwise I's say the Mallory horn meets the requirement of standard hardware just as well as the original horn.