Stall Horn - Easy Fix?

OkieAviator

OkieAviator

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OkieAviator
I have a pneumatic stall horn and to be honest not sure in the 6 hours I've flown the plane if it's ever worked. But after doing stall the other day and then before flying today having someone blow directly into it, it's clear it doesn't work. You can hear the air coming through the channel and out the horn, just no sound.

Are there any troubleshooting things I can do before engaging an A&P? I'm in the process of redoing the interior so it's feasible that I may have knocked something around, who knows.
 
He's right. You need vacuum on the stall horn port to make it sing. And if it's a Cessna, it is adjustable to make it squeal at the proper speed. If you get up there make sure spider webs and bugs are cleared before you inhale. :)
 
Okay that would be problem 1... easy fix. I'll give it a good suck tomorrow... :)
 
Stewartb said:
He's right. You need vacuum on the stall horn port to make it sing. And if it's a Cessna, it is adjustable to make it squeal at the proper speed. If you get up there make sure spider webs and bugs are cleared before you inhale. :)
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Mostly we use a light hanky or rag to suck through unless you need additional protein in your diet :yes:

Jim
 
Okay, doesn't matter which way the air is going, no sound. Guess it's time to get an A&P to check it out.
 
If it is a Cessna you just need to pull the door pillar plastic on the left side. Be careful not to crack it as it may be brittle. Near the top of the pillar and near the air vent will be the stall horn. It simply attaches VIA a hose clamp. The horn slides into a piece of hose. Any insulation in there will just pull out and you can access the hose clamp to release the horn. A replacement horn will be around $30.00. Sometimes you can clean the horn and clear any debris that might stop the reeds from vibrating thus producing the sound. Mine old Stall Horn is sitting on my desk. :)

Check with your A&P, he might let you do most or all of the work, which he will then check and sign-off if it meets the requirements.

These are the best pictures I have. The stall horn is behind the air vent in this picture. I had to remove the metal cover on the aluminum panel on the exterior of the plane. Good luck.
 

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Just so happens I'm redoing the interior now so the door pillar is already off. Yesterday I pulled the horn out to look at it. It didn't have any type of reed in end of it so maybe that's the issue. I thought maybe the reed was further down towards the wing, but if it's not and it's supposed to be at the end of the horn before the clamp then it probably fell out. I guess the fact that I was able to hand pull the horn out fairly easily means the clamp is loose.

Thanks!
 
The reed is inside my horn and is visible with a flashlight. My reed appeared to be a tad corroded so I replaced the horn. I don't like my new horn as it is too squeaky. I like the old one that is more masculine and easier for me to hear. LOL

My old horn works and I use it to annoy the dogs. :)

Good Luck !!
 
Thanks again for the input. When I go in tomorrow I'm going to look to see if it's stuck somewhere in the wing. If it's not I'll see if the A&P has an extra one or I'll buy a new one.
 
Your wing port for the stall horn is not close to the door post. Are you sure you aren't looking for the stall warning reed in the cockpit air vent intake? The stall horn port is a horizontal opening approx 5/16" tall and 3/4" wide that is positioned outboard of the air vent intakes. In the case of my 180 the horn port is right in front of the strut-wing attach. I don't recall that being different from other Cessnas.
 
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Correct the port on the leading edge of the wing is a few inches from the strut. In the cabin the horn is about an inch up and to the left from the air vent. That horn is what I pulled out.
 
Just in case you don't have a service manual, here's a page out of my 180 manual.
 

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I looked in the service manual I had and all that was in there was a paragraph about pneumatic stall horns. I pulled off part 2 (horn) the other day and it lacks any type of reed.

Whats the adjustable plate?
 
Okay the reed was about 4 inches into the hose. I had to drill it out and then dig the little pieces out with a screw driver and a shopvac. Going to order a new reed and hope it doesn't get sucked in there again.

Edit: New reed from Aircraft Spruce was 75 cents... so I ordered 2... then as usual I start ordering more things, ordered some new flap buttons because the painters didn't put any on... and an external screw kit because it saves me from having to search around a hardware store for them.
 
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OkieAviator said:
Okay the reed was about 4 inches into the hose. I had to drill it out and then dig the little pieces out with a screw driver and a shopvac. Going to order a new reed and hope it doesn't get sucked in there again.

Edit: New reed from Aircraft Spruce was 75 cents... so I ordered 2... then as usual I start ordering more things, ordered some new flap buttons because the painters didn't put any on... and an external screw kit because it saves me from having to search around a hardware store for them.
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We used to give owners a discount on their annual if they went down and bought a screw kit for their plane. It saves a bunch of time not trying to salvage marginal screws and then having to go through coffee cans of hardware to find the ones you inevitably have to replace. It was your option for me to replace them all (painting the heads cost extra) or just the ones that needed it and you take home the left overs. I used to just keep a drill with bit collared for depth and this little twisted volcano looking extractor in a 1/4" drive speed wrench. With that I can remove any screw in under 10 seconds regardless how stripped.
 
In the end it was a pretty easy fix. Reed came in yesterday so I went out this morning, reclamped the horn back to the hose, pushed the reed into the horn and then put the plastic plate back over. Took some pictures so when I meet the A&P to get some of my latest interior work inspected he doesn't have to pull the plastics and the plate off.

For fun here's some before and after pictures. If people are curious I used Vantage Plane Plastics and their Ventube kit. I reused the temp guage and that collar piece. Also it's not completely screwed in, so that's why there's about a 1/2 inch gap on the top left. I'll do that tomorrow when I get the headliner all secured.
 

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Henning said:
Nice, are you looking to do the whole interior in that color?
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Yes the plastics. The vinyl and carpet are slate and flint. Here is a picture of the right side door panel and.. whatever that front panel is called. I'll wait till I have the seats and carpet done before I put the door welt in... which is that slate color as well.
 

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OkieAviator said:
Yes the plastics. The vinyl and carpet are slate and flint. Here is a picture of the right side door panel and.. whatever that front panel is called. I'll wait till I have the seats and carpet done before I put the door welt in... which is that slate color as well.
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Nice, that's called the kick panel BTW.
 
OkieAviator said:
Thanks and Thanks. I'm enjoying the process and am learning a lot about the plane in doing this work myself.
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Yeah, as you're seeing, there's nothing particularly difficult about working on a plane, they are basic machines at the end of it all. They are not particularly accepting of inattentive work though. Just continue on to do good work and you'll find that aircraft ownership doesn't have to be hugely burdensome. When you do a lot of the nickel and dime work yourself, you save a lot of money to have available for the more expensive things.
 
My method is throw a rag over it, give it a good 1 second suck and call it a day.

On a side note today was the first time for me to go up since fixing it. Worked like a champ. With the STOL kit you really have to get slow and pitched up to get it to make noise.
 
OkieAviator said:
My method is throw a rag over it, give it a good 1 second suck and call it a day.
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True, but with the Sporty's toy you don't have to get on a step stool to get high enough off the ground to suck on the thing. Just a thought...
 
I think you have to buy the whole party horn. Wentworth had a box of them at Oshkosh. I'd call them.

Frankly, I think having one of these unfurl into the cockpit would be a good warning device:
party-horn.jpg
 
flyingron said:
I think you have to buy the whole party horn. Wentworth had a box of them at Oshkosh. I'd call them.

Frankly, I think having one of these unfurl into the cockpit would be a good warning device:
party-horn.jpg
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Especially for those wearing noise canceling headsets, having a visual indicator is a good idea.
 
BigBadLou said:
Um, guys, this is a family-friendly forum, mmmmkay? ;)
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Last I checked, "family friendly" meant someone had to have sex. Just sayin'. That's the typical way to have a family, anyway. :)

This is the joke that goes through my head when I hear someplace is "family friendly".

Wow. They let folks do that there?! You'd think that making families wouldn't be allowed in a place that handles food. ;)
 
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