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  #1  
Old 05-04-2018, 09:41 AM
polkaking27 polkaking27 is offline
 
Join Date: May 2017
Location: murray
Posts: 31
Default Newb question: Aileron inputs and Mag check

Hi all,

I just bought me a beautiful rv-8 from another member on here. I'm loving it, but have a couple of questions.

During run-up I'm noticing a couple of things.
1-When I have my brakes applied and I check to see if my controls are free and correct I can feel some resistance in the ailerons. When I release the brakes everything is fine and there is no resistance. Is there some sort of interference between the brakes and the aileron controls? Is this normal or something I should look further into?

2- When I do a mag check I get no/very little RPM drop on either right or left mags. I've looked up other threads on this so I tried to troubleshoot myself. I don't see an appreciable rise in EGT on either mag, and when I turn it to off the engine will shut down. Is it possible that the mags are so well timed that I'm not seeing a drop in rpm or rise in EGT, or is one of my p leads bad?

Thanks so much for your help. I feel like I'm at a huge disadvantage to all of you guys because you built your airplanes and know them in and out. Hopefully I can get as comfortable with the mechanical workings as you guys are after my first condition inspection.

Thanks
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  #2  
Old 05-04-2018, 09:49 AM
jabarr jabarr is offline
 
Join Date: Sep 2008
Location: Fayetteville, Georgia
Posts: 183
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Resistance is not normal. There is no tie between brakes and ailerons. Suggest you investigate before further flight.
What type ignition are you running? If 2 electronic ignitions, very little drop is normal. If running mags, it could be a sign of timing being too advanced.
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  #3  
Old 05-04-2018, 10:30 AM
jump4way jump4way is offline
 
Join Date: Sep 2008
Location: Coolidge, AZ
Posts: 294
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I wonder if the interference is actually the rudder cables interfering with the aileron push rod? It might be worth pulling the floor beneath the pilot seat and check that out.
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  #4  
Old 05-04-2018, 11:09 AM
polkaking27 polkaking27 is offline
 
Join Date: May 2017
Location: murray
Posts: 31
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Okay thanks, I didn't think there should be any correlation between the brakes and ailerons. I'll pull the floor boards and look into it a little bit.

As far as the ignition goes, I am running dual mags. Everything else that I have flown has had dual mags and I always see at least a small drop in rpm. With these, if I'm trying to be picky I maybe see a drop of 10 rpm. I run it up to 1800 rpm to do my mag check. Is that standard or do I need to go to 2000?
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  #5  
Old 05-04-2018, 11:12 AM
jabarr jabarr is offline
 
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Location: Fayetteville, Georgia
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You need to have the mag timing checked. No drop is not good.
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  #6  
Old 05-04-2018, 12:35 PM
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Mike S Mike S is offline
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
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Quote:
Originally Posted by polkaking27 View Post
Hi all,

I just bought me a beautiful rv-8 from another member on here.
First off, congrats on the new plane

Do you have the adjustable rudder pedals or not? I have no idea if there is any connection to the problem, but might be??? Someone who knows the design better might be find the info useful to help diagnose the issue.
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  #7  
Old 05-04-2018, 01:45 PM
jibby212 jibby212 is offline
 
Join Date: Oct 2014
Location: Sarasota Fl
Posts: 120
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Could one mag have a broken ground circuit therefore never turning off?
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  #8  
Old 05-04-2018, 01:46 PM
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RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,005
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Quote:
Originally Posted by polkaking27 View Post
Okay thanks, I didn't think there should be any correlation between the brakes and ailerons. I'll pull the floor boards and look into it a little bit.

As far as the ignition goes, I am running dual mags. Everything else that I have flown has had dual mags and I always see at least a small drop in rpm. With these, if I'm trying to be picky I maybe see a drop of 10 rpm. I run it up to 1800 rpm to do my mag check. Is that standard or do I need to go to 2000?
Quote:
Originally Posted by jabarr View Post
You need to have the mag timing checked. No drop is not good.
IF your carb idle mixture is too lean, you can also get a low or no mag RPM drop. IF you do a mag check on an airplane with dual mags that has the carb set correctly, one can pull the mixture out some (lean the engine) and get very little to no mag drop on a lean mixture.
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  #9  
Old 05-04-2018, 02:08 PM
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keen9a keen9a is offline
 
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Location: St. Louis, MO
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When you are on the brakes are you compressing the seat cushion into the stick? Or even your leg (its amazing what we don't notice when focused on something else!)?
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  #10  
Old 05-04-2018, 02:09 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,331
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Start simple. Put an ohmmeter on the ignition switch (engine and power off) and confirm that on L the right mag is grounded, and vice versa on R.
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