"break-in" props  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       


11mm BIG BORE CONVERSION CARBURETOR WALBRO WT324 with STACK 26.65
Seller:  bat.guy
Details:   $26.65   |  11/22/2008   |  Classified Ad
We will rotate YOUR AD in this spot if you select "Forum Featured" when placing or editing your ad!

All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Gas Engines >> "break-in" props
Page: [1]

Login
Message << Older Topic   Newer Topic >>
"break-in" props - 4/5/2008 2:52:38 PM   
Josey Wales



Posts: 4699
Joined: 7/27/2003
From: **, NJ, USA
Status: offline 		Are break in props really necessary ? why cant you just pick an appropriate size for the engine you have and just fly ?

_____________________________

Joe
       Post #: 1

RE: "break-in" props - 4/5/2008 4:02:52 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		You can
It's more important not to let the engine overheat like from running it on a bench, long uplines ,or hoverbatics.
Once things have a chance to heat cycle a few times by flying it easy for a gallon or so to lossen up leter rip.
Look at the breakin for a weed whacker oh there isn't any and they live a life of torture.
If an engine isn't machined correctly no amount of brealkin will fix it.

_____________________________

land of the FREE: you're free to get a JOB not a handout.
home of the BRAVE: they paid for it and you're enjoying it

(in reply to Josey Wales)
       Post #: 2

RE: "break-in" props - 4/5/2008 4:04:01 PM   
RTK


 

Posts: 4040
Joined: 4/20/2003
From: CENTRAL , CA, USA
Status: offline 		Ditto

(in reply to skiman762)
       Post #: 3

RE: "break-in" props - 4/5/2008 4:16:30 PM   
altavillan


 

Posts: 1206
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Depends on the type of rings and cylinder wall lining. Sorta of speculating, and a bit from experience, but I think if your engine has twin or one smallish ring, more care is needed to allow seating to take place. Putting to large of a load might cause excessive amounts of hot gasses to leak past the rings and then all sorts of bad things happen. Larger single rings or duals from my experience tend to not need as much tender treatment. It's taking more than 12 gallons of fuel to get the rings seated in my currant engine. Two small rings. I've kept trying to put the larger prop on but only recently has it not lost compression when switching to the larger prop.

_____________________________

I didn''t put the bullet in the fire and you quit talking about my mother! "Cosby, Shop Class, 1968 or so"

(in reply to RTK)
       Post #: 4

RE: "break-in" props - 4/5/2008 5:07:13 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		So what event or measurment to you use to say the rings are seated
and how did you determine the engine lost compression with a larger prop
do you do a cranking compression check or a leak down check
just curious you never can learn enough in one lifetime

_____________________________

land of the FREE: you're free to get a JOB not a handout.
home of the BRAVE: they paid for it and you're enjoying it

(in reply to altavillan)
       Post #: 5

RE: "break-in" props - 4/5/2008 8:54:43 PM   
altavillan


 

Posts: 1206
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Just by feel. After the engine is all cooled down its was very easy to pull the prop through compression after running the 28x10 prop. Then I'll put the 27x10 back on and it will rebuild the seal. About the last 6 flights have been on the 28x10 and it is holding compression. Still not quite as good as with the 27x10 and I'll watch by feel to see if more time is needed on the 27" prop.
I have a 3W56, it has one big ring. It has built and maintained compression from day 1. Using straight syn oil it took some time to get there. But it never fell off from having too large of a prop.

_____________________________

I didn''t put the bullet in the fire and you quit talking about my mother! "Cosby, Shop Class, 1968 or so"

(in reply to skiman762)
       Post #: 6

RE: "break-in" props - 4/5/2008 11:25:32 PM   
Tired Old Man


 

Posts: 12041
Joined: 2/25/2002
From: Central, CA, USA
Status: online 		A leak down test is the most accurate. It provides a more accurate idea of the ring condition. A basic compression juts shows that the rings are maintainting a seal over a few revolutions. As for the break in prop thing, it's all about heat. Load an engine too much and it gets hot. That can be done with either a prop, too low or too high rpm, or all three combined. Keeping an engine within a "safe" temperature zone and load will not be a problem. A smaller prop than required for flight is the easiest way to avoid "loading" an engine, but keeping a new ringed engine too cold doesn't do it any favors.

For me, once an engine has lost compression I've never got any back. But that's just me. I have to replace the ring at minimum when it happens. Better to replace the entire top end but that gets pretty expensive in a hurry.

_____________________________

If you can''t fix it with a hammer, you have an electrical problem.

(in reply to altavillan)
       Post #: 7

RE: "break-in" props - 4/6/2008 2:21:04 AM   
altavillan


 

Posts: 1206
Joined: 10/24/2004
From: Altaville, CA, USA
Status: offline 		Fire up that engine thats been sitting all a lonesome in your Suk for a year and a half and learn a new 1 or 3 new ways to break in the worlds most PITA engine.

_____________________________

I didn''t put the bullet in the fire and you quit talking about my mother! "Cosby, Shop Class, 1968 or so"

(in reply to Tired Old Man)
       Post #: 8

RE: "break-in" props - 4/6/2008 4:05:09 AM   
Tired Old Man


 

Posts: 12041
Joined: 2/25/2002
From: Central, CA, USA
Status: online 		That's coming very soon. Prolly need a breaker bar to break the ring loose from the cylinder wall.... Btw, it's a Yak

_____________________________

If you can''t fix it with a hammer, you have an electrical problem.

(in reply to altavillan)
       Post #: 9

RE: "break-in" props - 4/6/2008 5:48:01 AM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		I had chainsaw given to me that was frozen I poured about an once of wt40 in put the sparkplug back in and hit it with a heatgun did the heat and cool thing 4 times and put a strap wrench on the flywheel and she came free and seems no worse for wear

_____________________________

land of the FREE: you're free to get a JOB not a handout.
home of the BRAVE: they paid for it and you're enjoying it

(in reply to Tired Old Man)
       Post #: 10

RE: "break-in" props - 4/6/2008 5:56:17 AM   
mmattockx


 

Posts: 2256
Joined: 4/28/2005
From: Calgary, AB, CANADA
Status: offline
quote:

ORIGINAL: skiman762

I had chainsaw given to me that was frozen I poured about an once of wt40 in put the sparkplug back in and hit it with a heatgun did the heat and cool thing 4 times and put a strap wrench on the flywheel and she came free and seems no worse for wear


ATF is pretty good at this, as well. It takes patience and persistence a lot of times, not brute force.

But I bet Pat already knows that...


Mark

_____________________________

Waco Brotherhood #4

(in reply to skiman762)
       Post #: 11

Page:   [1]
All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Gas Engines >> "break-in" props
Page: [1]





Jump to:


Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine |