So, as of yesterday I have 11 flights since rebuild. Yesterday's was only a half hour.
I have several issues to address, but the most pressing is high oil temps. For years, I was a happy camper with oil temps and I strongly felt that a properly cowled and baffled O-200 would not need an oil cooler. Unfortunately, that changed with my new setup and I think the primary issue is with the new composite sump. The old oil tank was a big bulky piece of steel that was a marvelous heat sink.
My new sump doesn't conduct heat for beans and it is more much compact. Now, I get about 20 minutes of flight before the oil is dancing around 225F. (OAT of 57F).
I tried installing one of those finned heat sinks over my oil filter, then built a cooling shroud for it with a 1-1/2" hose leading up to it. Unfortunately, when I flew yesterday, it didn't seem to help a bit.
So now, I guess I'll be exploring the oil cooler option.
Rats.
Saturday, August 22, 2009
Monday, August 03, 2009
A Stuffed Engine Compartment
I was fooling around with the camera and photo editing program to see if I could make some ghost images of the engine compartment. This will help allow me to see where I might have extra room. I found that using Picase Web Albums, I could upload the photos and present slideshows. So here they are. If it seems to bog your computer down, let me know and I'll pull them off. Click of the photos for a larger view.
Looking at the right side of the cowling...
Here is the front view...
And looking at the left...
Looking at the right side of the cowling...
Here is the front view...
And looking at the left...
Baseline Measurements
Today I talked to my friend Harry Hinckley about my plane. Harry is the chief pilot and engineer for Greg Zimmerman's very fast SX300. In this past AventureCup race Harry turned a blistering 298 mph, so when Harry talks, I listen.
When I was talking about where I was in the project, Harry asked me about my baseline numbers. As a Six Sigma Black Belt, I know all about data collection, I just get lazy and don't practice what I know I should do.
So after talking to Harry, I went out and made a ground static run, short test flight, and gathered a little more data.
Total cowling inlets: 22 sq. in
Total cowling outlet 28 sq. in. (kind of estimated)
Static & ground runup
ATIS Temp/dew: 27/16 C = 80/61F
Baro: 30.03"
Dynon Outside Air Temp (OAT) sensor: 84F = 29C
Static RPM 2,400, MAP 30"
Test Altitude: 5,500'
OAT: 59F = 15C, Dynon Density Altitude: 6,700 ft.
WOT RPM: 2,850 - 2,900 RPM MAP 24.5"
IAS: 170 mph, TAS: 188 MPH
Oil temp: 215F
I found some test data from May 23, 2005, also flown at 5,500 feet. At that time, I was able to get about 3,000 RPM and had a corrected airspeed of 199 mph.
I'll refer back to this post, to see what effect my changes make.
When I was talking about where I was in the project, Harry asked me about my baseline numbers. As a Six Sigma Black Belt, I know all about data collection, I just get lazy and don't practice what I know I should do.
So after talking to Harry, I went out and made a ground static run, short test flight, and gathered a little more data.
Total cowling inlets: 22 sq. in
Total cowling outlet 28 sq. in. (kind of estimated)
Static & ground runup
ATIS Temp/dew: 27/16 C = 80/61F
Baro: 30.03"
Dynon Outside Air Temp (OAT) sensor: 84F = 29C
Static RPM 2,400, MAP 30"
Test Altitude: 5,500'
OAT: 59F = 15C, Dynon Density Altitude: 6,700 ft.
WOT RPM: 2,850 - 2,900 RPM MAP 24.5"
IAS: 170 mph, TAS: 188 MPH
Oil temp: 215F
I found some test data from May 23, 2005, also flown at 5,500 feet. At that time, I was able to get about 3,000 RPM and had a corrected airspeed of 199 mph.
I'll refer back to this post, to see what effect my changes make.
Saturday, August 01, 2009
A Few More Flights
I am now up to six flights since the big rebuild. I had a big one yesterday - up for over an hour, which is a lot for someone who is expecting (fearing) the engine to quite any minute. Actually, I'm getting a little more confidence and think this may work out.
Much of the time has been spent fine tuning the mixture mapping for the EC3 and that is getting better. I also took care of the roll trim issue, by adjusting the length of the elevator push rods.
Here is what the mixture mapping looks like. As you can see, I have more tweaking to do. Click on it for a larger image. Get it?
I bounced the first three landings, but the last three have been better, so I am coming along. C-Rod says, even though any landing you can walk away from is a good one - you get extra points if you can reuse the airplane.
I am generally tooling around at lower throttle settings, around 2,300 RPM, since I'm not in a hurry to get anywhere. The oil temperature seems to be holding around 200-205F and I need to work on that.
Today, at wide open throttle (WOT) I got about 2,800RPM. I flew my last AirVenture Cup race at 3,050 RPM, so I have big work there. I am going to try all other means, but I believe the handwriting is on the wall to change back to a straight in-line induction system. Of course that means more design and more fiberglass and more painting. Yeauch.
As far as speeds go, I think I may not be too bad. Today at 3,100 feet, I briefly held 2,620 RPM with 26" MAP and got 159 mph IAS. The Dynon's displayed TAS was 167. I still need to check airspeed calibration, but I think those figures might be a little better than before.
I really need to get the RPMs over 3,000 to see what I have wrought.
Much of the time has been spent fine tuning the mixture mapping for the EC3 and that is getting better. I also took care of the roll trim issue, by adjusting the length of the elevator push rods.
Here is what the mixture mapping looks like. As you can see, I have more tweaking to do. Click on it for a larger image. Get it?
I bounced the first three landings, but the last three have been better, so I am coming along. C-Rod says, even though any landing you can walk away from is a good one - you get extra points if you can reuse the airplane.
I am generally tooling around at lower throttle settings, around 2,300 RPM, since I'm not in a hurry to get anywhere. The oil temperature seems to be holding around 200-205F and I need to work on that.
Today, at wide open throttle (WOT) I got about 2,800RPM. I flew my last AirVenture Cup race at 3,050 RPM, so I have big work there. I am going to try all other means, but I believe the handwriting is on the wall to change back to a straight in-line induction system. Of course that means more design and more fiberglass and more painting. Yeauch.
As far as speeds go, I think I may not be too bad. Today at 3,100 feet, I briefly held 2,620 RPM with 26" MAP and got 159 mph IAS. The Dynon's displayed TAS was 167. I still need to check airspeed calibration, but I think those figures might be a little better than before.
I really need to get the RPMs over 3,000 to see what I have wrought.
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