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Matched engine speed - 1/22/2003 5:25:36 AM   
WLJ



Posts: 414
Joined: 1/2/2002
From: Enfield, NC, USA
Status: offline 		First Twin, C-160, OS46 2 strokes. How close in RPM do engines need to run, and do you turn INTO or AWAY FROM engine out? Thanks, WLJ
       Post #: 1

Matched engine speed - 1/22/2003 5:42:10 AM   
Flyfalcons



Posts: 6100
Joined: 7/27/2002
From: Bonney Lake, WA, USA
Status: offline 		Turn away from the dead engine.

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Ryan Winslow

Cub flying - the new EXTREME SPORT!!! (evarrr)

(in reply to WLJ)
       Post #: 2

Matched engine speed - 1/22/2003 6:48:07 AM   
JohnBuckner



Posts: 3935
Joined: 12/23/2001
From: Kingman, AZ, USA
Status: online 		Also Rudder into the good engine for the remainder of the flight untill power reduction for the landing.

John

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"Keep your controllines tight"

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       Post #: 3

Engine RPM - 1/22/2003 9:09:05 AM   
jamesg33


 

Posts: 63
Joined: 1/26/2002
From: Saint Peters, MO, USA
Status: offline 		I try to get the engines on my Duelist (OS 46's) within 300-400 RPM of each other at about 2/3 throttle. Even a 500 rpm difference is barely noticeable in the air. I have flown it with as much as a 1000 rpm difference, which definitely made the plane pull to one side, but a little rudder trim took care of it.

Once I accidentally flew it with a 10-8 prop on one engine and a 10-7 on the other. I was amazed at how noticeable that was! Even though I'd sync'd the engines pretty good the plane really wanted to turn on me once airborne.

I got hung up on trying to sync my engines when I first got the plane (even bought a tach that I now barely use) but soon realized that it's more important to get them running good and reliably (usually on the rich side). I then just stand in front of the plane and listen to the sound as I run the engines up - if you get a "warbling" sound instead of a constant "drone" they're too far out out of sync and need adjusting.

Good luck with your twin!

Jim

(in reply to WLJ)
       Post #: 4

Thanks - 1/23/2003 3:50:15 AM   
WLJ



Posts: 414
Joined: 1/2/2002
From: Enfield, NC, USA
Status: offline 		I really appreciate the information. I think i'm going to like twins. Got my eye on a OV-10. WLJ

(in reply to WLJ)
       Post #: 5

Matched engine speed - 1/23/2003 7:44:58 PM   
mulligan



Posts: 1147
Joined: 4/14/2002
From: Sanford, FL, USA
Status: offline 		Before matching engines, don't forget to match props!! Otherwise, matching engine RPMs is meaningless.

Take a few props (of the same size, Jim ), and run them on the same engine at full throttle. Match the props in pairs that have the closest RPMs.

- George

(in reply to WLJ)
       Post #: 6

Matched engine speed - 1/24/2003 4:06:07 AM   
DICKEYBIRD



Posts: 2668
Joined: 4/8/2002
From: Collierville, TN, USA
Status: online 		[QUOTE]Originally posted by mulligan
Before matching engines, don't forget to match props!! Otherwise, matching engine RPMs is meaningless.

Take a few props (of the same size, Jim ), and run them on the same engine at full throttle. Match the props in pairs that have the closest RPMs. [/QUOTE]
I go one step further on my small engine powered twin. If they just don't sound right in the air, I have swapped props from one side to the other and got a "sweeter" sounding match.

_____________________________

"He who dies with the most good Cox engines wins!"

(in reply to WLJ)
       Post #: 7

Matched engine speed - 1/24/2003 4:10:06 AM   
mulligan



Posts: 1147
Joined: 4/14/2002
From: Sanford, FL, USA
Status: offline 		Cox-a-holics???

Sheesh, you'd think they'd come up with something a little different

- George

(in reply to WLJ)
       Post #: 8

Matched engine speed - 1/24/2003 4:20:40 AM   
DICKEYBIRD



Posts: 2668
Joined: 4/8/2002
From: Collierville, TN, USA
Status: online 		Say what?? You lost me.

_____________________________

"He who dies with the most good Cox engines wins!"

(in reply to WLJ)
       Post #: 9

Matched engine speed - 1/24/2003 4:35:16 AM   
mulligan



Posts: 1147
Joined: 4/14/2002
From: Sanford, FL, USA
Status: offline 		I'm reading your Avatar COX logo, wherein it states, "Cox-a-holics Anonymous"

Seems, ahem, provocative.

- George

(in reply to WLJ)
       Post #: 10

Matched engine speed - 1/24/2003 4:49:51 AM   
DICKEYBIRD



Posts: 2668
Joined: 4/8/2002
From: Collierville, TN, USA
Status: online 		[QUOTE]Originally posted by mulligan
Seems, ahem, provocative.[/QUOTE]
Naah, I just love the little bastids. That's what I started the hobby with uhhh, 44 years ago: Cox .049's. I have gone full circle, all the way up to 1/3 scale with biggie engines and now have nostalgically reverted back to Cox; where I started!

There's a group of us that have learned how to tame them and make reliable runners out of them. I just call it "Cox-a-holics Anonymous" and whimsically made up the logo and use it as my avatar. I guess those with a perverted side might read something else into it but hey, check the spelling!

_____________________________

"He who dies with the most good Cox engines wins!"

(in reply to WLJ)
       Post #: 11

Matched engine speed - 1/24/2003 5:13:37 AM   
JohnBuckner



Posts: 3935
Joined: 12/23/2001
From: Kingman, AZ, USA
Status: online 		Naaww Don,t listen to em Dickeybird, I love the logo and there are still plenty of us lovers of the finer mechanical things in life left.

John

_____________________________

"Keep your controllines tight"

(in reply to WLJ)
       Post #: 12

Matched engine speed - 1/24/2003 6:08:12 PM   
DICKEYBIRD



Posts: 2668
Joined: 4/8/2002
From: Collierville, TN, USA
Status: online 		[QUOTE]Originally posted by JohnBuckner
there are still plenty of us lovers of the finer mechanical things in life left. [/QUOTE]
Amen brother!

_____________________________

"He who dies with the most good Cox engines wins!"

(in reply to WLJ)
       Post #: 13

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