Top Coat on the engine cowling

Today I decided it was time for the engine cowling to go blue.  I finished up the final sanding on the cowling to 320 grit.  The cowling didn’t need primer any where except for where I expanded the left cowling out to fit the engine.  I have been filling and sand for several weeks now on and off.   So I shot a final primer coat on to those parts and then let them dry.  While those parts were drying I shot a first coat of eko-fill on the gear leg fairings.  This really highlighted the pin holes in the leg.  I nearly had to sand most of it off and I will need to re-shoot them.  On Thursday I worked on the turtle deck by sanding the latest batch of clear coat in hopes of filling in some of pin holes.  It sort of works but its a real PITA.  I think I got it good enough and will use primer from here on out.    Anyway back to the cowling.  Once the primer was dry I sanded it down with 320 and then wiped everything real good with 91% alcohol loaded them in to the booth mixed paint and started shooting.  41 min later they looked like this:

The next day I took them out for a photo shoot:

And for all you video folks:

Time spent today 8 hours

Total Time spent 1268 hours

Spraying the 2nd cross coat and priming the left cowling extension

Tonight I cleaned off the upper wing and re-hung it in the paint booth and shot the 2nd cross coat. I also shot the lower left cowling extension with the white primer. Not much to else to say.

Time spent 2 hours
Total time spent 1200 hours

Spraying the Upper wing and body filler on the cowling

Today I spent a bunch of time working on each cowling. I spent most of the time on the cowling that needed an extension to fix the engine (left side) it took several iterations to get the cowling as smooth as I wanted but I eventually did. I also prepped the upper wing by wiping it with 320 sandpaper to get the bumps off from the brush coats of Eko-fill. I then hung it in the paint booth and sprayed it. I found that one cross coat of the upper wing with the 1.3mm tip 23-25 psi at the gun takes approx 2/3 of the hopper of paint. After it was done and dried I did the initial sanding with my orbital sander and scotch brite pad.

Time spent today 8 hours
Total time spent 1198 hours

3rd X coat on the Istruts, stabs, rudder and elevators starting cowling prep

Today I took the morning to go flying with my buddy to work on my instrument rating. This afternoon I started prepping the left side cowling for paint. It will need a bit of body filler as this is the side that I had to widen for the engine to fit. It also has some areas that need some filler to fill in some voids after the molding process. I started by sanding all the gel coat down with 320 to give it some grit for the paint and to also clean it up since it had bugs and other things on it. The sanding worked really well the cowling looks great. After that I re-installed the ladder back into the paint booth and hung the I-struts, right stab, rudder and elevators for their 3rd cross coat.

Time spent 5 hours
Total time spent 1190 hours

New cowling oil temp issue, conditional inspection ect.

This a a roll up of about a weekends worth of work done over a month (due to school consuming all my time)  Now that the temp have been increasing and summer is here I have have been having problems keep the oil temp down to a reasonable level.  It has been slowly increasing from 220 deg to back in Late April  on a particularly hot day it hit 240 degrees flying aerobatics.  This was the final straw that caused me to figure this out.

It turns out that my front baffle is seeing some rather high pressures at normal flight speeds and really high pressures flying aerobatics.  It was blowing the baffle back about 1.5 inches braking the seal between the silicone baffle seal and the cowling and allowing air under my motor.  This caused really poor airflow to my oil cooler and to my cylinders thus causing the high temps.  I also had problems with the silicone baffle seal to staying forward.

I  relocated the oil cooler back to the front on the right side of the cowling just in front of the #1 cylinder.  I beefed up the baffle to accept the cooler and then added a bracket back the engine sump bolts.  Now the entire right side of the forward baffle is rigid.  The left side was stiffened up by installed a 3/4″ by 3/4″ 0.32 angle riveted diagonally from the air intake to the top of the forward baffle.  I then installed another bracket off the injection servo to the lower lip of the baffle to support the baffle and keep it rigid.  Finally I took a 3 inch by 3/32 silicone baffle seal and caused it to conform to the elliptical shape of the forward baffle I made a 3/4″ by 1/2 ” 0.32 angle and stretch the outside edge of the 3/4″ angle to make the shape of the curve.  This acts like a long washer and allows the baffle seal to conform to the shape without puckering where it attaches. Here are some pictures…

I went out a flew the plane for a 1.1.  in 75 deg day and the highest temps I saw was 193 degrees flying nothing but Aerobatics.  Cruise flight I see 183-185 deg oil temp.

Furthermore.  Conducted a conditional inspection of the plane  all seemed well.

Total time spent 25 hours.

Happiness is flying inverted!

Absolutely gorgeous weekend logged a 0.6 snapped a photo while I was inverted.   The plane is running great.  Life is good!

More Test flying of the New Cowling

Well this is a roll up of several days flying. I have flown 3 more flights or 1.7 hours since the last post. After the first flight I removed the cowling and checked everything over, all is well. As far as performance goes I pretty much end up at 143.5 MPH True Airspeed at 2700 RPM at 7.0 GPH at 5000 FT. I have tried the numbers now 4 different times and keep coming up with the same numbers. The plane is climbing out 2650 RPM. I may be under propped a bit and a friend of mine has offered to let me borrow his 76″ dia 66″ pitch pitch.

On another subject I have seen good numbers on the CHT’s no issues there however I have seen larger numbers on the Oil temps during Akro I have seen 210 which is 20 deg higher then I am used to at mod OAT’s so at this cold of temps I imagine i have some work to do on the oil cooler hood I already Knew this though.

As far as energy management the cowling really helps it allows me to pick up speed very quickly. I have noticed that if I push over to the 45 or less I will quick past through 170 to 180 which is great when flying out of maneuvers that cap out. I really notice cowling drag reduction during from base to final I am carrying way more speed then I usually do.

All in all I think it is a good mod some day I will try out the a different prop to see it that helps out but I will stick with what I have for now.

Flying time 1.7 hours total time since cowling mod 2.1 hours total time on the engine 87.0

Test Flying the New Cowling

Well this afternoon I as able to catch a test flight with the new cowling. First off everything went very well. Some temporary perf numbers…I say temporary because it was cold as all hell outside and it was pretty late and the sun was going down.

2700 RPM 32 Deg F OAT 3000 FT 143 MPH True A/S which is less then before but my fuel flow is down to 7.0-7.5 GPH from 8.5-9.0 GPH.

Fire walled (the speed was still building and so was the RPM so I backed off) 3300 RPM 195 MPH Straight and level. I will also explore this test point again as I was kinda in a hurry and just wanted to get a ball park figure.

Note: I was just quickly trying these points and I will go out and try them again in the future like I said I was just trying to get a feel for the the new cowling and what it was capable of. I am a little unsure of the true airspeed number and would like to go out and try that again. I can tell you the plane seemed nice and smooth and also seemed to climb well. The RPM seemed to want to run away on my a bit. It liked to run right around 2950 to 3000 RPM with excursion into the 3200 range. The CHT’s were right at 350 deg F. Oil temp was right at 180 deg F.

I will try this again after I take the cowl off to inspect everything make sure nothing is leaking. I will get back with some more concrete numbers as I get them.

Flight time today 0.3 hours Total time on Engine 85.3 hours total time on the cowl 0.3 hours

Finished up the cowling mod

I dug the foam and clay out of the now cured oil cooler hood.  This took a bit I used some acetone to help wipe the clay out of the fiberglass.  I then took some sand paper and sanded down the area where the engine mount could interface and I also sanded down where the SCAT duct attaches since it didn’t quite fit with the several layers of glass was added.   Did some last minute routing and securing of wires and hoses.  I reinstalled the oil cooler with the new hood which took some trimming to get to fit right.   I then double and triple checked everything and I then re-installed the cowl.  As soon as the I got the last screw in the cowl I heard some piter patter on the hangar roof it started raining so no test flight or ground run today.  Tomorrow is supposed to be cold windy and rainy so I guess the flight and ground run will have to wait.  Oh well.

Time spent today 3.5 hours total time spent 87.5 hours

More little things to clean up

I spent the day finishing off the mold for the oil cooler hood.  I was lucky and found the right size foam cylinder for the SCAT duct.  I used some clay to make the radius’s. Most of the time was spent making the oil dip stick door.  I used Tony’s (Wolf Aircraft) advice on utilizing the blank that I cut out for the door for the door itself.  This worked out great.  I added a shim on the piano hinge to make the top of the piano hinge sit flush with the top of the cowl.  I also added a piece of the 0.032 aluminum for the door to rest against and a place for the camlock fastener receptical.  Anyway I am really happy with the door and it is perfectly placed.  I went home later and glassed up the hood with a couple of layers.

Time spent 9 hours total time spent 84 hours