Oil on the windshield. What would you do?

[Tony Cox]

Here's a question that anyone with a single
engine, constant speed prop might have to
deal with sometime.

You're cruising along happily when suddenly
oil drops start appearing on the windshield. There
is no "bang" or anything else to indicate catastrophic
failure. The nearest airport is out of gliding range.
What do you do?

I'd assume symptoms were caused by some prop seal
failure. I'd go to fine pitch (to minimize further oil
loss) & then reduce RPM to where I could still maintain
altitude (to further minimize oil loss, and to minimize
structural damage if the prop were about to disintegrate)
while heading for the nearest airport.

Can anyone think of a better response?

[Robert M. Gary]

On Jan 27, 8:28 am, "Tony Cox" > wrote:
> I'd assume symptoms were caused by some prop seal
> failure. I'd go to fine pitch (to minimize further oil
> loss) & then reduce RPM to where I could still maintain
> altitude (to further minimize oil loss, and to minimize
> structural damage if the prop were about to disintegrate)
> while heading for the nearest airport.

I'd probably avoid touching anything and head towards the airport.
Could a prop seal really leak enough oil to make drops appear on the
windscreen? Usually prop seal leaks show up as moisture under the
prop.

-Robert, CFII

[Tony Cox]

On Jan 27, 9:01 am, "Robert M. Gary" > wrote:
> On Jan 27, 8:28 am, "Tony Cox" > wrote:
>
> Could a prop seal really leak enough oil to make drops appear on the
> windscreen? Usually prop seal leaks show up as moisture under the
> prop.

As it happens, this is what happened to a friend of mine
yesterday (although on approach, not in cruise) and we were
debating what might be the proper response had an airport
not been within easy reach. The oil was more like filthy black
streaks, rather than "drops". Still, it was obvious what it was.

[Grumman-581[_1_]]

On Sat, 27 Jan 2007 08:28:13 -0800, in
om>, Tony Cox wrote:
> Can anyone think of a better response?

Get out your bottle of windex and paper towels, pull back the canopy, and
clean the windshield?

[Jon Kraus]

That is just a stupid response and you know it... You should declare an
emergency and pull the ballistic parachute... :-)




Grumman-581 wrote:
> On Sat, 27 Jan 2007 08:28:13 -0800, in
> om>, Tony Cox wrote:
>
>>Can anyone think of a better response?
>
>
> Get out your bottle of windex and paper towels, pull back the canopy, and
> clean the windshield?

[Grumman-581[_1_]]

On Sat, 27 Jan 2007 12:47:44 -0500, in
>, Jon Kraus wrote:
> That is just a stupid response and you know it... You should declare an
> emergency and pull the ballistic parachute... :-)

Awh 'ell, I've got a canopy, so obviously all I need to do is just pull
the ejection seat firing handle... <grin>

[Bob Fry]

Pretend nohing is wrong and stay the course. Don't cut and run!
--
Go, and never darken my towels again.
Groucho Marx

[Bob Noel]

In article om>,
"Tony Cox" > wrote:

> You're cruising along happily when suddenly
> oil drops start appearing on the windshield. There
> is no "bang" or anything else to indicate catastrophic
> failure. The nearest airport is out of gliding range.
> What do you do?

head for the nearest suitable airport (taking into consideration
terrain that I'd overfly)

--
Bob Noel
Looking for a sig the
lawyers will hate

[george]

On Jan 28, 8:09 am, Bob Noel >
wrote:
> In article om>,
> "Tony Cox" > wrote:
>
> > You're cruising along happily when suddenly
> > oil drops start appearing on the windshield. There
> > is no "bang" or anything else to indicate catastrophic
> > failure. The nearest airport is out of gliding range.
> > What do you do?head for the nearest suitable airport (taking into consideration
> terrain that I'd overfly)

Yup. I'd be examining the ground near me for a forced landing area
while asking the nearest airfield to put the kettle on for my surprise
visit.
A friend who had this occur in a Percival Proctor was unaware of the
oil loss. However the tower told him that he had smoke.
Fastest 180 and downwind landing they ever saw :-)

[Roy Smith]

In article m>,
"george" > wrote:

> On Jan 28, 8:09 am, Bob Noel >
> wrote:
> > In article om>,
> > "Tony Cox" > wrote:
> >
> > > You're cruising along happily when suddenly
> > > oil drops start appearing on the windshield. There
> > > is no "bang" or anything else to indicate catastrophic
> > > failure. The nearest airport is out of gliding range.
> > > What do you do?head for the nearest suitable airport (taking into
> > > consideration
> > terrain that I'd overfly)

I've always figured I would start to climb (and, of course, head for the
nearest airport while doing that). If I've got a fixed amount of time that
the engine is going to continue to run, I'll use that time to store up as
much energy as I can in the form of altitude.

[G. Sylvester]

Grumman-581 wrote:
> On Sat, 27 Jan 2007 08:28:13 -0800, in
> om>, Tony Cox wrote:
>> Can anyone think of a better response?
> Get out your bottle of windex and paper towels, pull back the canopy, and
> clean the windshield?

Do what John Belushi did in the Blues Brothers, take out the napkins,
lean out the window and clean the passenger side window.

"Tower. This is Cessna N12345. We're in a field."

Gerald

[M[_1_]]

Of course, there's always a chance that a higher power setting used in
a climb would make the catastrophic failure occur sooner.

On Jan 27, 11:50 am, Roy Smith > wrote:
> I've always figured I would start to climb (and, of course, head for the
> nearest airport while doing that). If I've got a fixed amount of time that
> the engine is going to continue to run, I'll use that time to store up as
> much energy as I can in the form of altitude.

[Duncan (NZ)]

In article om>,
says...
> Here's a question that anyone with a single
> engine, constant speed prop might have to
> deal with sometime.
>
> You're cruising along happily when suddenly
> oil drops start appearing on the windshield. There
> is no "bang" or anything else to indicate catastrophic
> failure. The nearest airport is out of gliding range.
> What do you do?
>
> I'd assume symptoms were caused by some prop seal
> failure. I'd go to fine pitch (to minimize further oil
> loss) & then reduce RPM to where I could still maintain
> altitude (to further minimize oil loss, and to minimize
> structural damage if the prop were about to disintegrate)
> while heading for the nearest airport.
>
> Can anyone think of a better response?

One of our club planes (a C-172) blew a frost plug in flight - they
continued flight to reach the field (10 minutes), landing with no oil
found in the engine. (Can't recall the bill for the engine rebuild but
it was tens of thousands).

Saving grace may well have been topping up the oil before departure -
what is it? 6.5 quarts? I'm sure they were glad of every drop.

I'd do what you have sugggested, and make for the nearest field.

--
Duncan

[[email protected]]

A "frost plug" in an aircooled motor????? Geez I can see a oil line
plug but most of those are the screw in type, not press fit ...

On Jan 27, 5:14 pm, Duncan (NZ) > wrote:
> In article om>,
> says...
>
>
>
>
>
> > Here's a question that anyone with a single
> > engine, constant speed prop might have to
> > deal with sometime.
>
> > You're cruising along happily when suddenly
> > oil drops start appearing on the windshield. There
> > is no "bang" or anything else to indicate catastrophic
> > failure. The nearest airport is out of gliding range.
> > What do you do?
>
> > I'd assume symptoms were caused by some prop seal
> > failure. I'd go to fine pitch (to minimize further oil
> > loss) & then reduce RPM to where I could still maintain
> > altitude (to further minimize oil loss, and to minimize
> > structural damage if the prop were about to disintegrate)
> > while heading for the nearest airport.
>
> > Can anyone think of a better response?One of our club planes (a C-172) blew a frost plug in flight - they
> continued flight to reach the field (10 minutes), landing with no oil
> found in the engine. (Can't recall the bill for the engine rebuild but
> it was tens of thousands).
>
> Saving grace may well have been topping up the oil before departure -
> what is it? 6.5 quarts? I'm sure they were glad of every drop.
>
> I'd do what you have sugggested, and make for the nearest field.
>
> --
> Duncan- Hide quoted text -- Show quoted text -

[G. Sylvester]

Duncan (NZ) wrote:
> One of our club planes (a C-172) blew a frost plug in flight - they
> continued flight to reach the field (10 minutes), landing with no oil
> found in the engine. (Can't recall the bill for the engine rebuild but
> it was tens of thousands).
>...
> I'd do what you have sugggested, and make for the nearest field.

it depends on what kind of field is below. It might be better to spend
$20k on the engine and making the field than crashing in the field,
wrecking the plane and killing yourself.

As for the money aspect, in a club plane, the maintenance of the plane
is entirely up the club (or owner on lease back). They charge a renter
are fee for renting the plane which includes the maintenance on the
plane. As a renter, I expect to get a plane that will not have any kind
of failure. If it fails, I am not going to risk my life nor my
passengers lives to save the owner some money. Much of the reason I say
this is because the head of MX at my club also owns or owned ~8 a/c
online. They were known to have serious MX issues that this head of MX
and owner conveniently wrote off as fixed. Most CFI refused to fly them
yet plenty of renters rented them. Yea, conflict of interest the club
refused to fix. I fly the only a/c online that is not maintained by the
club. it's older but in excellent condition and everything works nearly
every time. And I would love to join a different club or own my own
plane but so far sticking to this one airplane is the best choice for
me. So back to the original question, the cost of the repair of a club
plane will not affect my decision whatsoever. In return, I treat the
aircraft that I rent as though it was my own. I fully clean up the
interior afterwards often nicer than the way I received the plane and
treat the engine and avionics like they were my own. I also give
frequent PIREPS to the owner. Oh, and of course make the most gentle
of landings every single time. ;-)

Gerald

[BT]

touch nothing, divert to the nearest airfield,
monitor oil temperature and pressure, low oil levels will cause temperature
to increase,
you already know you are loosing oil but at what rate?
low oil pressure might mean the oil sump is about empty.
it would take a lot of oil for that to happen, you may not be able to see
out the front then
but remember that not all the oil will be on the windshield, some will be on
the belly etc
remain high for glide if the engine does quit

if there is a tower where you are going, call them early and request
priority, tell them you suspect an engine oil loss problem.
if it is only a uncontrolled field, call and let them know early, just in
case you have to land in that field one mile short, they will be looking for
you

the oil will "streak" in the slip stream
changing power prop settings "even to fine" will cause the seals in the prop
hub to flex, why move them more than you have too.

BT

"Tony Cox" > wrote in message
ups.com...
> Here's a question that anyone with a single
> engine, constant speed prop might have to
> deal with sometime.
>
> You're cruising along happily when suddenly
> oil drops start appearing on the windshield. There
> is no "bang" or anything else to indicate catastrophic
> failure. The nearest airport is out of gliding range.
> What do you do?
>
> I'd assume symptoms were caused by some prop seal
> failure. I'd go to fine pitch (to minimize further oil
> loss) & then reduce RPM to where I could still maintain
> altitude (to further minimize oil loss, and to minimize
> structural damage if the prop were about to disintegrate)
> while heading for the nearest airport.
>
> Can anyone think of a better response?
>

[Duncan (NZ)]

In article om>,
says...
> A "frost plug" in an aircooled motor????? Geez I can see a oil line
> plug but most of those are the screw in type, not press fit ...

heh - I'll see if I can find the write up - I think one was done in a
newsletter. But yer right, it obviously wasn't a frost plug.

--
Duncan

[B A R R Y]

On Sat, 27 Jan 2007 18:25:05 -0800, "BT" > wrote:

>touch nothing, divert to the nearest airfield,

I've heard a statistic tossed around at Wings seminars stating that
most engine failures occur during a change or adjustment. Guest
engine experts seem to always agree not to touch anything if it's
still running and high confidence of the exact problem isn't
available.

I wish I could find the detailed information. Has anyone else heard
this?

[Ash Wyllie]

BT opined

>the oil will "streak" in the slip stream
>changing power prop settings "even to fine" will cause the seals in the prop
>hub to flex, why move them more than you have too.

Because the governor is constantly changing the blade angle, and thus
aggravating the leak. Going to fine pitch means that the blades will move
only once more for the rest of the flight.



-ash
Cthulhu in 2007!
Why wait for nature?

[Ron Natalie]

Robert M. Gary wrote:

>
> I'd probably avoid touching anything and head towards the airport.
> Could a prop seal really leak enough oil to make drops appear on the
> windscreen? Usually prop seal leaks show up as moisture under the
> prop.
>

If the engine is running a prop seal will most definitely throw
oil on the windshield. I can related two different props. In
the case of the old Hartzell bladder controllable props (like
many 50's era Navions, Bonanazas, Commanches) the bladder will
start to fail and throw a small amount of oil. It does this
right before you get around to replacing that bladder (it's
supposed to be replaced every three years, but I usually did
it every other year).

Back years ago one of my professors from college was restoring
a Taylorcraft. A bunch of us aviation minded folk headed out
to the airport with him. Two guys got assigned to hold the
tail and I was inside the cockpit on the throttle and switches
while the prof swung the prop. Right after the engine start
and in the seconds before I got it shutdown the prop seal
blew. The prof was fine as he was in front of the prop.
I was OK because I was inside the aircraft...but the two
guys holding the tail got nicely greased.

[Frank Barchi]

"Duncan (NZ)" > wrote in message
. nz...
> In article om>,
> says...
>> A "frost plug" in an aircooled motor????? Geez I can see a oil line
>> plug but most of those are the screw in type, not press fit ...
>
> heh - I'll see if I can find the write up - I think one was done in a
> newsletter. But yer right, it obviously wasn't a frost plug.
>
> --
> Duncan

I think maybe he means the crankcase breather. If that freezes, it'll blow
the oil overboard pretty quickly.
Having flown several thousand hours towing banners, a leaky prop seal is
quite common, and pretty much a non- issue in the airplanes I fly (PA-18/
J-3 with lyc o-360 and fixed pitch propeller). Depending on the condition of
the seal, usually they leak about 1-2 qts. over a 5-6 hour day. It's more of
a hazard to visibility than to the engine. It may be different for an
airplane with a constant speed prop. I haven't nor would I ground an
airplane for it, then again, your results may vary.

Frank

[Capt. Geoffrey Thorpe]

"Robert M. Gary" > wrote in message
oups.com...
>
<...> I'd probably avoid touching anything and head towards the airport.
> Could a prop seal really leak enough oil to make drops appear on the
> windscreen? Usually prop seal leaks show up as moisture under the
> prop.
>
> -Robert, CFII
>

A blown seal (just about anywhere) can result in oil on the windscreen. My
brother blew an oil pressure sending unit that is under the cowl and ended
up with the greasy windshield syndrome (T-18).
If there is an airport within gliding range, sure, pull back the power - it
might save you an overhaul. I wouldn't shut down the engine unless you have
a glider rating and are skilled at real life dead stick landings. Otherwise,
just point towards the nearest airport - no need to panic. Depending on what
kind of seal blew out, it can take a few minutes to actually pump all the
oil overboard. And, even without any measurable oil pressure an engine will
keep running for five to fifteen minutes. Easing off a bit on the power can
help it last longer. The big problem is going to be making the approach and
landing with an oil covered windshield. If you are accumulating a lot of oil
on the windscreen you won't be able to see out - this is a real problem for
an off field landing where you won't be able to see obstructions like wires.


--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[Jim Macklin]

Prop seals leak because people use the blades as tow-bars on
the ground. Front crankcase seals leak because of blocked
case vents.

In-flight, centrifugal forces make the pressure on the seals
at right angles, does not cause leaks.


"Ash Wyllie" > wrote in message
...
| BT opined
|
| >the oil will "streak" in the slip stream
| >changing power prop settings "even to fine" will cause
the seals in the prop
| >hub to flex, why move them more than you have too.
|
| Because the governor is constantly changing the blade
angle, and thus
| aggravating the leak. Going to fine pitch means that the
blades will move
| only once more for the rest of the flight.
|
|
|
| -ash
| Cthulhu in 2007!
| Why wait for nature?
|
|

[Doug[_1_]]

One thing to consider. You may have a choice of airports. The closest
one has no mechanic and the further one has a mechanic.

I would pick up flight following. I might file a flight plan if I
wasnt on one, if there was time.

[BT]

I've heard the same thing Barry.. don't know where the stats are found
BT

"B A R R Y" > wrote in message
...
> On Sat, 27 Jan 2007 18:25:05 -0800, "BT" > wrote:
>
>>touch nothing, divert to the nearest airfield,
>
> I've heard a statistic tossed around at Wings seminars stating that
> most engine failures occur during a change or adjustment. Guest
> engine experts seem to always agree not to touch anything if it's
> still running and high confidence of the exact problem isn't
> available.
>
> I wish I could find the detailed information. Has anyone else heard
> this?

[Dave[_5_]]

"What to do about it" depends entirely on how much oil. In addition to
the prop seals, it could also be the front crankshaft seal or the oil
filler gasket. I have had both - and neither was casuse for panic. The
former I had my mechanic attend to, and the latter I fixed myself.
I've never had leaky prop seals in 29 years of flying behind a CS prop
- but my former mechanic had a prop that leaked a bit on his own
plane. He chose to live with it for awhile - apparently a little was
not much cause for concern.

The incident that got my attention happened many years ago when I was
in a partnership that owned a Cessna 150. One fine day I went for a
flight, and soon streaks of oil started working their way up the
windshield. I of course headed for the nearest
airport. An inspection revealed nothing apparently amiss. I had a
mechanic wash down the engine compartment with solvent, then look into
the access door while I ran it up to
a pretty high RPM. Nothing. Took off again and all was well - but I
went home anyway.

The truth came out later when I related the incident to my partner. It
seems that he had committed the sin of leaving the dipstick unsecured
- and, of course, got oil all over the place when He took off. Even
worse, he wiped up all the oil he could see - and failed to tell
anyone or leave a note. So my day had been spoiled for nothing.

David Johnson

[Doug[_1_]]

You do realize that the govenor changes blade angle when you change
power settings don't you?

On Jan 28, 7:02 am, "Ash Wyllie" > wrote:
> BT opined
>
> >the oil will "streak" in the slip stream
> >changing power prop settings "even to fine" will cause the seals in the prop
> >hub to flex, why move them more than you have too.Because the governor is constantly changing the blade angle, and thus
> aggravating the leak. Going to fine pitch means that the blades will move
> only once more for the rest of the flight.
>
> -ash
> Cthulhu in 2007!
> Why wait for nature?

[Ron Natalie]

Jim Macklin wrote:
> Prop seals leak because people use the blades as tow-bars on
> the ground. Front crankcase seals leak because of blocked
> case vents.
>
That's a gross oversimplification. As I said, the old
Hartzell prop seals go because they are life limitted to
a few years. They aren't even anywhere near the blades.
While there's grease up there in the blade hubs, there
ain't any engine oil.

Had a crankcase seal blow out because the case was misassembled.
Had nothing to do witht he vents.

> In-flight, centrifugal forces make the pressure on the seals
> at right angles, does not cause leaks.

What?
>

[Ron Natalie]

BT wrote:
> I've heard the same thing Barry.. don't know where the stats are found
> BT

No supporting stats. Lycoming has researched it and it's a myth.
You can find the info in their tech briefs on their website.

[Ash Wyllie]

Doug opined

>You do realize that the govenor changes blade angle when you change
>power settings don't you?

Yes, but if the prop is in in fine pitch, it can't get any finer.

>On Jan 28, 7:02 am, "Ash Wyllie" > wrote:
>> BT opined
>>
>> >the oil will "streak" in the slip stream
>> >changing power prop settings "even to fine" will cause the seals in the
>> >prop hub to flex, why move them more than you have too.Because the
>> >governor is constantly changing the blade angle, and thus
>> aggravating the leak. Going to fine pitch means that the blades will move
>> only once more for the rest of the flight.
>>
>> -ash
>> Cthulhu in 2007!
>> Why wait for nature?



-ash
Cthulhu in 2007!
Why wait for nature?

[Margy Natalie]

Robert M. Gary wrote:
>
> On Jan 27, 8:28 am, "Tony Cox" > wrote:
>
>>I'd assume symptoms were caused by some prop seal
>>failure. I'd go to fine pitch (to minimize further oil
>>loss) & then reduce RPM to where I could still maintain
>>altitude (to further minimize oil loss, and to minimize
>>structural damage if the prop were about to disintegrate)
>>while heading for the nearest airport.
>
>
> I'd probably avoid touching anything and head towards the airport.
> Could a prop seal really leak enough oil to make drops appear on the
> windscreen? Usually prop seal leaks show up as moisture under the
> prop.
>
> -Robert, CFII
>
We used to have an old diaphragm prop. I invited my teaching attendant
to go flying with us (in his younger years he flew P-51's and then flew
for Phillipine air). About halfway home the diaphragm started to go and
I mentioned it to Ron in the backseat as a way to make sure Jim (flying
in the right seat) didn't get concerned. It took him about 10 seconds
to transition to the instruments (it threw a bunch of oil on the right
side, but the left was ok).

Margy

[Grumman-581[_1_]]

On Sun, 28 Jan 2007 12:31:51 GMT, B A R R Y
> wrote:
> I've heard a statistic tossed around at Wings seminars stating that
> most engine failures occur during a change or adjustment. Guest
> engine experts seem to always agree not to touch anything if it's
> still running and high confidence of the exact problem isn't
> available.

Which would seem to indicate that if you can consistantly fly with
just two engine settings (full power and idle) you are less likely to
get unwelcome engine related surprises... <grin>

[Doug[_1_]]

On Jan 28, 6:59 pm, "Ash Wyllie" > wrote:
> Doug opined
>
> >You do realize that the govenor changes blade angle when you change
> >power settings don't you?
>
> Yes, but if the prop is in in fine pitch, it can't get any finer.

The above is incorrect on a constant speed prop, if what you mean is
the prop knob is all the way in ('fine"). There is really no way of
knowing exactly how fine the prop is currently running, but just
because you push the prop knob all the way in does NOT mean the prop
is all the way to the fine stops!!! It COULD be, but not necesarily.

If you push the prop knob in, he govenor makes the pitch as fine as
necesarry to get redline rpm, or until it hits the stops, whichever
comes first.

It is a mistaken belief that just because the prop knob is all the way
in, on a constant speed prop, that you are all the way to the stops.
Not true.

[B A R R Y[_2_]]

Grumman-581 wrote:
> On Sun, 28 Jan 2007 12:31:51 GMT, B A R R Y
> > wrote:
>> I've heard a statistic tossed around at Wings seminars stating that
>> most engine failures occur during a change or adjustment. Guest
>> engine experts seem to always agree not to touch anything if it's
>> still running and high confidence of the exact problem isn't
>> available.
>
> Which would seem to indicate that if you can consistantly fly with
> just two engine settings (full power and idle) you are less likely to
> get unwelcome engine related surprises... <grin>


Like the WW1 guys? <G>

[Peter Dohm]

> > I've heard the same thing Barry.. don't know where the stats are found
> > BT
>
> No supporting stats. Lycoming has researched it and it's a myth.
> You can find the info in their tech briefs on their website.

I heard it "around the airport" c1980. If there are stats, they are old.

About all I can add is that one of the locals had the engine drop to idle at
the first power reduction--probably at the crosswind turn--the clevis
connecting the throttle to the carburetor came loose. IIRC, he made a
successfull landing on the airport.

[Roger[_4_]]

On Sun, 4 Feb 2007 03:07:27 -0500, "Peter Dohm"
> wrote:

>> > I've heard the same thing Barry.. don't know where the stats are found
>> > BT
>>
>> No supporting stats. Lycoming has researched it and it's a myth.
>> You can find the info in their tech briefs on their website.
>
>I heard it "around the airport" c1980. If there are stats, they are old.
>
>About all I can add is that one of the locals had the engine drop to idle at
>the first power reduction--probably at the crosswind turn--the clevis

You sure it wasn't the "Deadly downwind turn?".

>connecting the throttle to the carburetor came loose. IIRC, he made a
>successfull landing on the airport.


>
>
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Roger[_4_]]

On 27 Jan 2007 08:28:13 -0800, "Tony Cox" > wrote:

>Here's a question that anyone with a single
>engine, constant speed prop might have to
>deal with sometime.
>
>You're cruising along happily when suddenly
>oil drops start appearing on the windshield. There
>is no "bang" or anything else to indicate catastrophic
>failure. The nearest airport is out of gliding range.
>What do you do?
>
>I'd assume symptoms were caused by some prop seal
>failure. I'd go to fine pitch (to minimize further oil
>loss) & then reduce RPM to where I could still maintain
>altitude (to further minimize oil loss, and to minimize
>structural damage if the prop were about to disintegrate)
>while heading for the nearest airport.
>
>Can anyone think of a better response?

Clean the windshield?

I had one that did that. landed, cleaned, wiped prop down, went
around the pattern, no more problem.

I know it was the seals as you could see the streaks down the blades.
Apparently they just didn't seat. That was something like three years
ago and no problem since. OTOH I haven't flown in 6 weeks due to the
weather so I'll have to pay close attention next time out. Bout time
for a couple hours of just practice.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com