The International Cessna^® 170 Association

Installing a new interior in 50V and was wondering if anyone has ever removed the old overhead speaker? I never use the thing and it sure would be nice to get rid of the bulge in the new headliner.

Yes you can BUT the speaker housing holds the bows for the headliner and the speaker holds the speaker housing in place. SOoo if really want to do this you need to find a bow of suitable material that is long enough to go from side to side and that isn't as easy as it might appear. Others have looked for the elusive rod of the right length, most available are short.

Obtaining new bows are nearly a impossibility, but have found using fibreglass fishing rod blanks works well. You can cut them to your size and they do not corrode either. You could also go hi-tech and use carbon fiber fishing rod blanks .

Thanks for the input guys. I’m going to call Airtex tomorrow for their ideas.

BTW, bet you didn't know the speaker was an OPTION. It was optional before the '52 B model and then again after 26996 and on.

Though I can't say I ever noticed a 170 that didn't have a speaker. Can't say I ever looked specially for it though. I'd bet a 170 that never had a speaker wouldn't have the two holes in the overhead sheet metal for the speaker which would be a clue it never had a speaker. (Or someone did some serious sheet metal replacement)

But as it was an option, bet Cessna must have sent some of them out of the factory with no speakers, AND the illusive long bow required.

Oh and one more thing. If you have an original speaker, DO NOT THROUGH IT OUT. That is a special size speaker with the magnets drilled and tapped to secure it to the roof. You CAN NOT find a replacement and originals are worse then hens teeth to find.

And then you might say, but the speaker is shot. It's garbage. WRONG. Son long as you have the frame and magnet the coil and speaker cone can be replace and the cost was/is very reasonable.

Louie,
I'm needing a speaker for my project. Let me know if you want to get rid of yours.

Bruce Fenstermacher wrote:Yes you can BUT the speaker housing holds the bows for the headliner and the speaker holds the speaker housing in place. SOoo if really want to do this you need to find a bow of suitable material that is long enough to go from side to side and that isn't as easy as it might appear. Others have looked for the elusive rod of the right length, most available are short.

Bruce,
It's interesting that Cessna doesn't show an alternative full length headliner bow for aircraft following s/n 26995. The '56-'62 C-172's continue to have the two half bows but don't have the speaker housing. They only have the speaker bolted to the roof. I think what they do on these later models without the speaker housing is mount the inboard end of the wires in a clip or angle which attaches to the roof. The inboard end of the headliner bow wire is not left hanging; it is supported. Note item 47 from the early 172 IPC. It's described as an "angle" —- there’s a left and right angle. I'm guessing it's purpose is to secure the inboard ends of the half-bows.Adding two of these clips to the roof's longitudinal hat sections to secure the inboard ends of the half bows would be quite easy.

You know Gary I was actually going to look in the IPC to see if Cessna called out a longer bow when the speaker was not used and got distracted. They do call out a different bow for the A model when the speaker is not installed than the two shorter "wires" used with the speaker.

No, do not delete the speaker - If for nothing else retaining Originality.

Retain the Slight Hump inside the cabin. Iconic reasons. There is a retiring Heavy A/C w a more pronounced exterior Top hump.

I will start another Post detailing the consumption of my original C170B speaker in S.N. 24633.

Yes it was meece.

The speaker is useful when visiting the aircraft while "on the ramp" and quickly listening to ATIS/AWOS/ASOS or local ground/air traffic either as a pre-flight activity, obtaining a pre-clearance, or anytime when not intending to immediately start the engine, without having to don a headset and/or also sharing broadcast info with another person. The reason the speaker was an "option" was because radios in-general were "options". In the time-period, cabin aircraft which had radios used speakers more than headsets (which were more common in open-cockpits. In fact, the speaker was seen as an additional advantage of "modern cabin aircraft", and the use of a headset w/mic required (by reg) there be a speaker and a hand-held mic in case the headset failed.* It was a selling-point of Narco radios (which had audio amplifiers incorporated) that they were capable of driving a speaker without an additional audio-amp.
Removal of the speaker may be considered a major alteration by some inspectors and that alone justifies it's retainer, IMO, but if so, may also require a 337, especially if on the original equipment list.

* Regardless, I personally consider it an important point to have a hand-held microphone in the aircraft for back-up should the headset or audio-panel fail.

gahorn wrote:* Regardless, I personally consider it an important point to have a hand-held microphone in the aircraft for back-up should the headset or audio-panel fail.

My backup mic and speakers in my 170 is the same as it is in the helicopter I fly for a living which has no speaker or microphone. It's another headset.

My aircraft speaker had been removed during a “restoration ‘’ and placed in a box that got very wet which wrecked the speaker. However on replacement it was noted the original speaker “impedance “ was very different from the ones you buy at the local electronics shop. The cost of a new speaker was eye watering from Cessna and the wait was 3 months . I picked up one from the aircraft grab yard at the airport for a can of beer . [it was surposed to be “graveyard” but not grab yard but the meaning is correct].

Bruce Fenstermacher wrote:

gahorn wrote:* Regardless, I personally consider it an important point to have a hand-held microphone in the aircraft for back-up should the headset or audio-panel fail.

My backup mic and speakers in my 170 is the same as it is in the helicopter I fly for a living which has no speaker or microphone. It's another headset.

The reason helicopters are equipped with dual headsets instead of backup speakers is because speakers are inaudible because helicopters make so much NOISE and VIBRATION that the EARTH REJECTS THEM.

(I'll bet your work-ride also uses dual/seperate audio panels/amps. Helicopters also require more "hands-on" the controls so less free time for hand-performed communications such as a hand-held microphone... a major reason dual headsets are standardized for them.) Certainly similar logic can be applied to fixed-wing aircraft but it's a design-change for our airplanes which may complicate the task as I inferred.

Many, many moons ago my original speaker quit working. Upon removal, I found that the paper cone had been chewed off right down to the magnet by a mouse, the remains of which were still in the vicinity. I didn’t throw the speaker away, but I didn’t know you could have a speaker re-coned either, so I replaced it with one out of an old 8-track home system I had as a teenager. I attached the speaker by gluing a 3/4” thick block of maple to the magnet with construction adhesive, then attaching that assembly to the cabin roof with wood screws and bevel washers through the original holes. The outer frame of the replacement speaker had the same footprint as the old one, so attaching the original baffle wasn’t a problem. There was most likely an impedance mismatch from the old speaker, but neither the old Narco MK12A, nor the later King KMA24 audio panel seemed to have a problem with it. That lasted 20+ years until the adhesive let go of the wood block.

I’m honestly not sure if Mountain Airframe replaced the speaker during the recent restoration, but the baffle is there, creating the requisite “hump” in the headliner, and (I think) a place to attach the original instrument and courtesy light panel. With 3 headsets, a handheld radio, and the iPad for preflight weather, I see absolutely no reason for an operational speaker, though out of habit I do keep a hand held microphone in the glove box, but I’ve lost track of how many decades it’s been since I’ve used it.

I have been carrying around a hand held mic for years and never used it. Then the other day on a clean up in the aircraft ,the mic was found under the back seat . So a quick inspection to,see if ok and to my surprise I found the end fitting was totally incompatible with the aircraft system. This was after many 100hrlys and a number of ramp checks.