Cessna 182 Cowl Flap

Those cowl flaps take a long time to fail. It would have been very apparent at the last annual, but was overlooked.

Everything around an engine vibrates. Cowl flaps are often mounted with piano hinges, and the vibration causes wear between the hinge halves and the pin. The pin gets thin. The hinge segments get thin. Then the forces pull it apart. On this particular airplane, there should have been some damage aft of the cowl flap, caused by the flap whacking around against the belly while still restrained by the control cable. But that cable, or the attachment bracket on the flap, or the cable clevis, had to have failed when the hinge let go. So they were completely shot, too.

Look at the flap on the other side. See that smoking rivet ahead of it? The one with a black ring around its head and a dark smear behind it? Loose rivet. More problems in the making.

All of that adds up to expensive repairs that are normally avoided by replacing stuff before it reaches that stage. Cheap annuals are false economies.
 
Dan Thomas said:
Look at the flap on the other side. See that smoking rivet ahead of it? The one with a black ring around its head and a dark smear behind it? Loose rivet. More problems in the making.
Click to expand...

Heh. We've got one of those. It's our "oil leak detector". Ha. (Our mechanic is watching it. But it really is a mess when we spill a little oil. LOL!)

That cowl just vibrates like hell up there. It's why on our model with the cowl mounted landing lights we were replacing two a year, until we went LED. That was soooooo worth it.

Also going to have to upsize a couple of the -- ahh, what the heck are the twist lock cam things called that hold the cowl halves together and the top cowl on... name escapes me right now. But if wiggled right, a couple of those can be popped out of the cowl when it's off the airplane.

And we have had some screws in the inspection plate under the rudder that would disappear after being replaced a couple of years ago, so those had to be upsized also.

It's always a job maintaining something that's nearly as old as I am! A car from that era would have needed a complete restoration by now. So it's pretty normal dealing with all this stuff.

We're probably overdue for a dynamic balance, too. That'd be nice.
 
Last edited:
Haha! Yeah that "smoking rivet" is where I spilled oil and it has found a place to slowly seep out. And yeah, I don't clean it as much as I should. Sue me.

I could use a balance myself. Also need some rigging work done.
 
OkieFlyer said:
Haha! Yeah that "smoking rivet" is where I spilled oil and it has found a place to slowly seep out. And yeah, I don't clean it as much as I should. Sue me.
Click to expand...

The "smoke" is aluminum oxide, a byproduct of relative movement. The rivet is getting smaller and the hole bigger, and whatever it's holding (flap hinge, in this case) is also wearing and placing more stress on adjacent rivets. Leaving it adds $$ in repair bills later.
 
Dan Thomas said:
The "smoke" is aluminum oxide, a byproduct of relative movement. The rivet is getting smaller and the hole bigger, and whatever it's holding (flap hinge, in this case) is also wearing and placing more stress on adjacent rivets. Leaving it adds $$ in repair bills later.
Click to expand...

Yep, just a matter of time before it "suddenly fails"..............
 
Very kind.

But I live in reality. A part fell off your airplane due to negligence, and the same part on the other side is heading in the same direction, yet you want to ignore that as well. And due to the negligence you are finding out just how expensive it's about to become.

Sorry the truth bothers you. May I suggest while you are looking for that expensive cowl flap buy both of them. Eventually your, ahem, "oil stained rivet" will work it's way loose on the other one and it will depart as well....."suddenly".

Mr. Thomas above stated it well:

Dan Thomas said:
All of that adds up to expensive repairs that are normally avoided by replacing stuff before it reaches that stage. Cheap annuals are false economies.
Click to expand...
 
Easy way to tell if its a smoking rivet. Take a felt tip marker, draw a line across it on to the body. The rivet will probably rotate a little as it rattles around, and you'll be able to see if with the line. No harm in checking it out. Also no harm in replacing that rivet. But easier to use the marker to see if its moving.
 
OkieFlyer said:
The "smoke" is oil. No ifs, ands, or buts. Moving on.
Click to expand...

There's oil in that smoke because the rivet is loose and leaking. Tight rivets, like those next to the smoking one, don't leak like that.

How much do you expect your airplane to be worth when you are ready to sell it? Too many guys find that their economies have cost them a whole lot of equity.
 
Guys, the question was about procuring a replacement cowl flap. I'm sure that if any of you individuals questioning the integrity of Andrew's aircraft wanted to go to Oklahoma and provide a free annual inspection (this would include travel expenses and all parts/labor for the repairs paid for by said individual performing the inspection) that he would consider accepting the offer. Personally I'd recommend he decline it, since it smells like a false economy.

In the mean time you've made your points that he should check the other side. Let's stop beating the dead horse. We want members to feel comfortable asking for help when needed, not worry that they come in with a maintenance question and have the forum attempt to perform an annual inspection via keyboard.
 
Last edited:
Well, shucks. If I were looking for torsional stability, I sure as hell wouldn't use a die-formed piece of soft aluminum. More probably some sort of small low-profile box structure made from stiff aluminum L-bracketry. Stronger, lighter, better.

Now, about the piano hinge ... how might we make that stronger, lighter, better?

Don't ever forget that a young engineer fresh out of school has to start somewhere and cowl flaps seem to be about as benign as anything else. I shudder to think that some of the stuffs I did back in those days are still flying around somewhere.
 
If you end up making the part, post pics. I'd love to see the process you go through.
Shouldn't be too hard to find a machine shop that can heat treat parts.
 
weirdjim said:
Now, about the piano hinge ... how might we make that stronger, lighter, better?
Click to expand...

Could do like Robertson did and just replace half of it with a larger one... hahaha... and now that Robertson is gone and some other yahoos own the STC, you get to pay $900 for two halves of a bigger piano hinge you could buy at Lowes... Because... aviation! LOL...
 
weirdjim said:
...
Now, about the piano hinge ... how might we make that stronger, lighter, better?
...
Click to expand...


Cowl off, cowl flaps open, run silicone the length of the hinge, about 2 inches wide and 1/4 thick and let it cure good, I use ultra grey now, oil does not affect it, it just makes the cowl flap not wear out the hinges
 
denverpilot said:
what the heck are the twist lock cam things called that hold the cowl halves together and the top cowl on...
Click to expand...
As in, father of Apollo? Mt. Olympus? Dzus!
 
Ted DuPuis said:
Guys, the question was about procuring a replacement cowl flap. I'm sure that if any of you individuals questioning the integrity of Andrew's aircraft wanted to go to Oklahoma and provide a free annual inspection (this would include travel expenses and all parts/labor for the repairs paid for by said individual performing the inspection) that he would consider accepting the offer. Personally I'd recommend he decline it, since it smells like a false economy.

In the mean time you've made your points that he should check the other side. Let's stop beating the dead horse. We want members to feel comfortable asking for help when needed, not worry that they come in with a maintenance question and have the forum attempt to perform an annual inspection via keyboard.
Click to expand...

Thank you Ted. I was beginning to think this thread had run it's course.

Yes indeedy, I will be checking the LH cowl flap and the rest of the cowling closely. Additionally, the LH cowl flap was repaired a couple years before I bought the plane, about 4-5 years ago if I recall. That doesn't mean it's free of wear obviously, but it has been worked on in the recent past, and is probably not in as bad a condition as the one that fell off. In the meantime, I'll be sure to do a more thorough job making sure I get in there and wipe out any oil that settled in the valleys around the countersunk rivet heads so as not to invite trouble in the future.

weirdjim said:
Well, shucks. If I were looking for torsional stability, I sure as hell wouldn't use a die-formed piece of soft aluminum. More probably some sort of small low-profile box structure made from stiff aluminum L-bracketry. Stronger, lighter, better.

Now, about the piano hinge ... how might we make that stronger, lighter, better?

Don't ever forget that a young engineer fresh out of school has to start somewhere and cowl flaps seem to be about as benign as anything else. I shudder to think that some of the stuffs I did back in those days are still flying around somewhere.
Click to expand...

Thank you WeirdJim. You actually bring up a good idea. My brother is a mechanical engineer. He might have some insight. I believe there are stainless hinges available. There is also some kind of beef up kit for the original cowl flaps. I think the outfit that offers it is Dynamic Propeller.

UngaWunga said:
If you end up making the part, post pics. I'd love to see the process you go through.
Shouldn't be too hard to find a machine shop that can heat treat parts.
Click to expand...

Roger that. Although, should I be parading my homebuilt parts around or keep it on the down low?

denverpilot said:
Could do like Robertson did and just replace half of it with a larger one... hahaha... and now that Robertson is gone and some other yahoos own the STC, you get to pay $900 for two halves of a bigger piano hinge you could buy at Lowes... Because... aviation! LOL...
Click to expand...

I heard that!

James331 said:
Cowl off, cowl flaps open, run silicone the length of the hinge, about 2 inches wide and 1/4 thick and let it cure good, I use ultra grey now, oil does not affect it, it just makes the cowl flap not wear out the hinges
Click to expand...

I'm not sure I follow. Where exactly is the 2 inch wide silicone going? Sorry.
 
Last edited:
OkieFlyer said:
Thank you Ted. I was beginning to think this thread had run it's course.

Yes indeedy, I will be checking the LH cowl flap and the rest of the cowling closely. Additionally, the LH cowl flap was repaired a couple years before I bought the plane, about 4-5 years ago if I recall. That doesn't mean it's free of wear obviously, but it has been worked on in the recent past, and is probably not in as bad a condition as the one that fell off. In the meantime, I'll be sure to do a more thorough job making sure I get in there and wipe out any oil that settled in the valleys around the countersunk rivet heads so as not to invite trouble in the future.



Thank you WeirdJim. You actually bring up a good idea. My brother is a mechanical engineer. He might have some insight. I believe there are stainless hinges available. There is also some kind of beef up kit for the original cowl flaps. I think the outfit that offers it is Dynamic Propeller.



Roger that. Although, should I be parading my homebuilt parts around or keep it on the down low?



I heard that!



I'm not sure I follow. Where exactly is the 2 inch wide silicone going? Sorry.
Click to expand...

Over the hinge, 2" wide going along the hinge.
 
denverpilot said:
Getting it in the hinge itself? What's it doing, acting like a little bumper between each ring of the piano hinge?
Click to expand...

Think it keeps it from rattling and just dampens it.
 
James331 said:
Think it keeps it from rattling and just dampens it.
Click to expand...

Interesting. I'm tempted to see what our mechanic thinks about doing it. Doesn't sound all that silly, really. And pretty easy to reverse if it's doing something naughty.
 
denverpilot said:
Interesting. I'm tempted to see what our mechanic thinks about doing it. Doesn't sound all that silly, really. And pretty easy to reverse if it's doing something naughty.
Click to expand...

Indeed. That came from some folks in a the skywagon group, but same deals for a 182 I'd imagine.
 
James331 said:
Cowl off, cowl flaps open, run silicone the length of the hinge, about 2 inches wide and 1/4 thick and let it cure good, I use ultra grey now, oil does not affect it, it just makes the cowl flap not wear out the hinges
Click to expand...
Doesn't that make the hinge and flap just a little difficult to operate from a friction and interference point of view?


Jim
 
60, and I've never had a BIT of trouble with my 182 cowl flaps. That's because the A model came out without them. I don't know how the hell Cessna certificated that airplane in Wichita in the middle of summer without them; I'm continuously a needle below redline with summer temperatures.

Jim
 
weirdjim said:
60, and I've never had a BIT of trouble with my 182 cowl flaps. That's because the A model came out without them. I don't know how the hell Cessna certificated that airplane in Wichita in the middle of summer without them; I'm continuously a needle below redline with summer temperatures.
Click to expand...

Because certification requires that you stay within certain limits. It does not require you to attain ideal goals.
 
OkieFlyer said:
Roger that. Although, should I be parading my homebuilt parts around or keep it on the down low?
Click to expand...

Owner produced parts can be just fine. Probably need to be able to show the material is equivalent to the original part. Remember also that owner can remove/replace non-structural stuff.
 
weirdjim said:
60, and I've never had a BIT of trouble with my 182 cowl flaps. That's because the A model came out without them. I don't know how the hell Cessna certificated that airplane in Wichita in the middle of summer without them; I'm continuously a needle below redline with summer temperatures.

Jim
Click to expand...
All test flights were at 5 a.m.? I think Piper did that with the turbo Dakota...
 
weirdjim said:
Doesn't that make the hinge and flap just a little difficult to operate from a friction and interference point of view?
Click to expand...

I wouldn't think so. The handle and cable arrangement exert a lot of force for what little you need to move them. Without air blowing against them, you can move them with a pinky finger.

Agree with the temps and needing them, though. Ours are usually wide open from start all the way to a few minutes into cruise when the CHT needle has moved down a another needle width to something that looks sane.

Probably that puts more stress on the silly piano hinges than anything. If you could actually close them after departure, they probably wouldn't wear nearly as much. But I won't even close them in a cruise climb configuration. Still don't like the look of the CHT gauge doing that.

Pattern work? They just stay open then, too.

O-470 isn't exactly known for running cool. Our oil cooler does a good job though. Oil temps tend to run a little low on ours. One out of two ain't bad, I guess. LOL.
 
Woohoo! Beegles Aircraft Services called me back today to tell me they found a cowl flap that should work. She's a little beat up, but I think we can whoop it back into shape fairly easily. We'll see

$100 plus shipping. Heck yeah!

I think I'm going to build a vacuum forming contraption and make a mold of that sucker.
 
Glad the Beegles tip paid off. They've provided various bits and bobs for our airplane over the years.

I have family in GXY and fly up there semi-regularly, and never thought to check them for our panel cover that was cracking... my two co-owners (when I had two) went up there one day to eat at the restaurant, they walk into Beegles on a whim, ask if they have a panel cover for a 182, and left with it 1/2 hour later. Score.
 
denverpilot said:
Glad the Beegles tip paid off. They've provided various bits and bobs for our airplane over the years.

I have family in GXY and fly up there semi-regularly, and never thought to check them for our panel cover that was cracking... my two co-owners (when I had two) went up there one day to eat at the restaurant, they walk into Beegles on a whim, ask if they have a panel cover for a 182, and left with it 1/2 hour later. Score.
Click to expand...

'Preciate the tip, brother. Honestly, in this day in age, I was surprised to have them call me back a week later and let me know they found one. Seems like a lot of businesses don't provide great customer service anymore, especially first time potential customers. On top of that, they seem like nice folks. I'll do business with them again.

A big thank you to all who gave input!
 
You must log in or register to reply here.
Back
Top