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  #1  
Old 10-14-2012, 08:16 AM
Bill.Peyton's Avatar
Bill.Peyton Bill.Peyton is offline
 
Join Date: Sep 2009
Location: St. Louis, MO
Posts: 1,885
Default First flight and CHTs

Wednesday was the first flight of N37CP. Everything went well. I have now flown 5 hours since then. The only issue I have are high CHTs. During climb I see 420 on number 5, with the remaining at 400. In cruise at 3000 ft @ 75% I see 360 on the coolest and 400 on the hottest. They have slowly been coming down with time. Number 5 continues to run the hottest , with 1&2 right behind. I decided to remove the left side vertical air dam. I saw a drop of 20 deg on number 2! It did not have any noticeable affect on 4&6. My plan is to remove the dam on the right side today.
Any suggestions on number 5? It's sealed up tight. My cowl is cut even with the firewall per the plans. Any other experience with the front dams. I see that Tim Olson has his trimmed down

Graph after left air dam removed



Graph prior to removal of air dam

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Bill Peyton
RV-10 - 1285 hours
N37CP
First Flight Oct 2012
Aviation Partners, LLC


WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.

Last edited by Bill.Peyton : 10-14-2012 at 09:02 AM.
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  #2  
Old 10-14-2012, 09:30 AM
Wayne Gillispie Wayne Gillispie is offline
 
Join Date: Apr 2009
Location: USA
Posts: 1,499
Default Congratulations on your first flight!

At 4 hrs, 125F ROP, 5468' DA, 68%, 55F OAT, OT 185F mine were running 347-388F. If running full throttle and takeoff EGT's, I would have been hotter. Air dams factory height. All built per plans with all new Van's supplied components. My #1 and #2 have always been the hottest, but the difference between them all have became closer with time.

Now at 88 hrs, 40F LOP, 8677' DA, 68%, 55F OAT, OT 200F(because I partially closed oil cooler damper as temps were not getting above 170F then snapped a pic as I always do. Normally try to keep them 180-185F) yesterday we were running 290-314F. No changes to air dams, but did cut slot out about 1 1/2" farther back. The slot did get my 90F climbs over 400F if I did not maintain 115 KIAS or better this summer. I plan on cutting my air dams down a little.

Check your air seals with a flashlight and mirror. With heat and air pressure they should be conforming good by now. I have more written data. These two flight numbers were from pics taken.
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  #3  
Old 10-14-2012, 09:43 AM
aerhed aerhed is offline
 
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Location: Big Sandy, WY
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Default

You'll find that #5 has the same baffle problem that the 360 guys have with #3. A washer or a dent giving a little space behind #5 may well drop you 10-20 degrees on #5. Although I can't prove it drops overall head temp as opposed to just lowering temp at the probe.
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  #4  
Old 10-14-2012, 10:05 AM
AaronG AaronG is offline
 
Join Date: Sep 2009
Location: Hartford, CT
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Your temps are about what I saw on my first flight. Now my hottest runs 360 rop and 330 lop in cruise, and just breaks 400 on a 80 degree day climbing out at 110 kts. I have vans standard setup with new engine.

Items that worked for me.

1). Let the engine break-in and rings seat.
2). Make sure all the holes in baffles are sealed with rtv
3) Cut back both air damns significantly which made big difference reducing #1 and #2 temps. Rest of cylinders did not change much.
4) installed wheel pants and leg fairings. This was worth the most, due to the higher speed of the plane.

Bottom line, I wouldn't worry too much for the first 100 hours and until all pants and fairings are installed. If the front 2 cylinders are running hotter than the back 4, you could start slowly removing air **** material to get them better matched.

Aaron
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  #5  
Old 10-14-2012, 10:08 AM
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Bill.Peyton Bill.Peyton is offline
 
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Aerhed,
Where would the washer be installed to open the gap?
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RV-10 - 1285 hours
N37CP
First Flight Oct 2012
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WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.
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  #6  
Old 10-14-2012, 10:13 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by Bill.Peyton View Post
Where would the washer be installed to open the gap?
Picture, 1000 words, etc:

http://www.vansairforce.com/communit...ght=hammerform
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  #7  
Old 10-14-2012, 10:20 AM
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Bill.Peyton Bill.Peyton is offline
 
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Location: St. Louis, MO
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I see! I will try the washers on next flight, if it works, then a removal and a mod to the rear baffle....
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RV-10 - 1285 hours
N37CP
First Flight Oct 2012
Aviation Partners, LLC


WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for their use.
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  #8  
Old 10-14-2012, 10:33 AM
David-aviator David-aviator is offline
 
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Location: Chesterfield, Missouri
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Congrats on the first flight, Bill. You will get the CHT's under control and if nothing else, it will run cooler as the engine breaks in.

PS I saw this airplane a few days ago and it is very, very nice. Bill does great work!!
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  #9  
Old 10-14-2012, 11:27 AM
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Mike S Mike S is online now
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,100
Default Congrats!!

Congratulations of getting her in the air

I also have high CHT issues with my 10.

What I have found helped most of all is increasing my climb airspeed, second was pulling the RPM back. After I get past the end of the runway, I pull back to 2300, or less, depending on where I am at, and how much of a hurry I am to get to cruise altitude. I try to maintain 140 mph in the climb.

Also, check the area between the cooling fins on the head, the location is below the spark plug, between the valves.

Look to see if there is any obstruction in there from casting flash. This has been a problem for many folks. The air passage between the fins must be clear.

Last, you are nowhere near being broken in, with only 5 hours.
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  #10  
Old 10-14-2012, 11:48 AM
N427EF N427EF is offline
 
Join Date: Oct 2005
Posts: 1,564
Default Congratulations!

Bill,
Congratulations on your first flight!
By the looks of your charts and description you are well within the borders of other RVs on their first flights.
What's different is, that you have all the advanced engine and data collecting tools at your disposal.
I wouldn't over analize the results at this point before you have accumulated 20 to 30 hours.
Plus 1 for the washer installation behind Cylinder #5 and cylinder#2 it makes a huge difference. I did this on my 8 after initial temps where a little high and installed spacers from the beginning on my 10. I have an MVP-50 engine analizer displaying and collecting data. Looking at the resulting graphs is my favorite thing besides flying.
I don't ever see cylinder temps over 400 and most of the year not even close.
My airdams are all in place just as the baffle kit provides and the only installation difference is the spacers behind #5 and in front of #2 cylinder.
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