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  #1  
Old 10-21-2014, 01:39 AM
Hansgiant Hansgiant is offline
 
Join Date: Apr 2013
Location: Johannesburg South Africa
Posts: 14
Default RV-12 Idle speed

Hello 12'ers

I recently had my carbs balanced which has made a huge difference to performance. However when pulling the power on landing my Idle speed is now 1900-2000 rpm.

What should it be? what is your idle speed with throttle closed?

Thanks a bunch

Hans
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  #2  
Old 10-21-2014, 05:51 AM
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f1rocket f1rocket is offline
 
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Location: Martinsville, IN
Posts: 2,342
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Van's recommends setting the idle at 1650 RPM. However, when sitting on the ground, you should idle above 1800. The Skyview will give you a warning below 1800.
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RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
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  #3  
Old 10-21-2014, 07:24 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,216
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There was a recent discussion about idle speed in THIS THREAD
If you do not want to read the whole thread, at least read post 33.
Van's Aircraft specifies on page 12-14 of the "RV-12 MAINTENANCE MANUAL" dated 08/12/13, "VERIFY THE IDLE SPEED AND ADJUST AS NECESSARY TO ACHIEVE 1600-1650 RPM AND SMOOTH ENGINE OPERATION".
The manual does not state the engine temperature, but according to a Van's employee, that idle RPM setting is at full operating temperature. If you want to make very short landings, a lower idle RPM will help.
Joe Gores
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  #4  
Old 11-01-2014, 12:50 PM
sandpiper sandpiper is offline
 
Join Date: Nov 2009
Location: Independence, OR
Posts: 317
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Quote:
Originally Posted by Hansgiant View Post
Hello 12'ers

I recently had my carbs balanced which has made a huge difference to performance. However when pulling the power on landing my Idle speed is now 1900-2000 rpm.

What should it be? what is your idle speed with throttle closed?

Thanks a bunch

Hans
Are you talking about idle speed while on final at normal approach speed? Or is this your idle speed on the ground?
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Independence, OR
LSRM-A, CFII
Rotax Service, Maintenance, and Heavy Maintenance Trained
Building an RV-12, N7878H reserved
Flying a Flight Design CTSW
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  #5  
Old 11-01-2014, 06:37 PM
Loki Loki is offline
 
Join Date: Oct 2014
Location: Marysvale, UT
Posts: 53
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Idle speed on the ground will be very different from in the air on approach. Depending on your nose down attitude rpm on approach may be 300-400 rpm higher than idle sitting on the ground.
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  #6  
Old 11-02-2014, 07:04 AM
Peterk Peterk is offline
 
Join Date: Mar 2008
Location: Texas
Posts: 1,378
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Interesting that so many RV12 pilots want a "correct" RPM speed on approach while refusing to fly a low airspeed. As Van's will tell you, a 50-55 kt final approach speed works great for landing with minimal float. That said, many, many RV12 pilots refuse to fly below 60-65 kts (or higher). Why is that? In most aircraft, approach airspeed can be managed very successfully with pitch. Who flies an approach by RPM?
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  #7  
Old 11-02-2014, 07:26 AM
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f1rocket f1rocket is offline
 
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I don't think the OP was trying to fly the approach by RPM, it was just a question regarding where the idle speed was being measured. I know the last thing I'm worried about is what the RPM is on final.

You are sure right about the fact that most probably don't slow the aircraft down as much as they should. I was sure guilty of that for some time. The reason is that I was used to flying the other RV aircraft at 60-65 kts and old habits are hard to break. The challenge I face on every landing is getting the altitude and airspeed nailed on final so I can keep the airspeed at 55 kts. The airplane doesn't want to slow down and if you are the least bit high, the only option is to lower the nose and pick up speed.

The RV-12 lands much nicer at 50 kts than 60 kts so I try real hard to hit that number. However our field is surrounded by trees and a ridge line off one end and it's only 2100' long, which calls for a little steeper approach than typical.
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Randy Pflanzer
Greenwood, IN

www.pflanzer-aviation.com
Paid through 2043!
Lund fishing Boat, 2017, GONE FISHING
RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
F1 EVO - partially completed, Sold
F1 Rocket - Completed 2005, Sold
RV-7A - Partially completed, Sold
RV-6 - Completed 2000, Sold
Long-EZ - Completed 1987, Sold

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  #8  
Old 11-02-2014, 08:59 AM
sandpiper sandpiper is offline
 
Join Date: Nov 2009
Location: Independence, OR
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How about slipping if you are too high? As opposed th lowering the nose and gaining airspeed.
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LSRM-A, CFII
Rotax Service, Maintenance, and Heavy Maintenance Trained
Building an RV-12, N7878H reserved
Flying a Flight Design CTSW
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  #9  
Old 11-02-2014, 10:06 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by f1rocket View Post
The challenge I face on every landing is getting the altitude and airspeed nailed on final so I can keep the airspeed at 55 kts. The airplane doesn't want to slow down and if you are the least bit high, the only option is to lower the nose and pick up speed.
Actually the way to get it to come down faster is to raise the nose and get slower.

As already mentioned, if the IAS is much above 50 Kts starting the round out for the flair, the airplane will be floating quite a ways down the runway, so I shoot for that unless I am making a landing at rather high weight.
I don't fly the entire final approach that slow though. I usually progressively loose airspeed from the point on downwind abeam the touchdown point so that I don't bog down traffic flow in the pattern, and then turn final at ~ 60 kts. If I find my self high on final, I slow to 50 kts much earlier, that will accelerate the rate of decent. If that is not enough, I add a bit of fwd slip to help.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
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RV-6A (aka "Junkyard Special ")
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  #10  
Old 11-02-2014, 12:48 PM
Mich48041 Mich48041 is offline
 
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Location: Riley TWP MI
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Usually pilots land into the wind. Slowing down takes longer to get to the runway and gives the wind more time to act on the aircraft. I do not look at the airspeed. I watch the AOA. If trying to land as short as possible, I keep the AOA in the yellow just below the red. If the computer voice yells "STALL", I relax the back pressure slightly. Below is a quote from the RV-12 Pilot's Operating Handbook.
Joe Gores
Quote:
Diving the aircraft in an attempt to lose altitude when flying into a headwind will only increase the required landing distance.
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