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!

No Action Lately Update on TPS

Sorry Folks but Test Pilot School has gotten crazy lately with a Calculus Test, Airborne Systems Test, Dynamics Test and 5 Difficiency Reports coming due all in one week.  I haven’t flown in a few weeks as it has been cold here and the winds have been whiping.

I also haven’t gotten to fly very much for school yet the pilots are still getting their NATOPS Qualifications completed in the T-38 and the T-6A so until that happens the chance of getting on the schedule is slim.  I did however finally get my T-38C Introduction flight a few weeks ago.  One thing to say about that aircraft is that it is every bit of a lawn dart.  Final approach is flown absoultly no slower than 160 Knots they are mostly flown at 170 to 175 knots depending on weight.  Shit happens fast at that speed.  5 mile final approaches happen in 2 minutes on the nut no time for mistakes.

The most interesting data point yet I did was asked to do a loop in the T-38 we started at 7K ft and 500 Knots and a 5 g pull holding the resultant AOA.  The top of the loop was at 17,000 Ft and we finished off right back again at 7,000 ft! yes folks it takes 10,000 feet to do a properly executed loop without over g’ing the aircraft.

We also went Super Sonic 1.05 Mach to be exact.  That sounds exciting but to tell the truth I wouldn’t have even known I done it with out looking at the Mach gage in the cockpit.  There really isn’t much if any decernable difference between sub sonic and super sonic flight in that aircraft no shockwaves no buffet, nothing at all.

The jet rolls pretty good but doesn’t roll much better then a hot Pitts S-2C or Extra.  It has nothing on the Edge 540 or Giles.

The climb out from the airport was pretty exciting as we went from 4500 feet to 41,000 feet in a few minutes. I want to remember something like 3 minutes with after burn clicked in.  Oh and by the way we climbed no slower than .87 Mach and spent most of the time at .95-.97 mach.

I will keep you updated as time allows. Right now I am pretty busy but I will fill you in with some more flight info hopefully soon.  Some upcoming flights will be in the C-12(King Air 200), and U-6 (Dehav – Beaver) for Handling Qualities Demo

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

Nick Nack Clean up

So Now that I have completed major construction on my cowl i have a bunch of nick nacks to clean up to finish this project. Today I installed the 2 1/2″ SCAT flange in to the #4 cylinder baffle for the oil cooler. I cut the old oil cooler lines down to the new size and reinstalled them. I removed the old 90 deg + 45 AN fittings in the oil cooler and re-placed them with a 90 deg flare to NPT fitting. I drilled a new hole for the #2 and #4 cylinder ignition wires since the 2 1/2″ SCAT flange took the place of the old ignition wire hole. I drilled all the holes for the screw that hold the baffle seal on. I installed a hose clamp for the intake SCAT duct. I permanently installed the exhaust and I re-routed some wires. I have some more things to get done like build a hood for the oil cooler, install the baffle seal material. Permenently install the prop and make an oil cooler access door. But there is no reason why I couldn’t get that done this week and try to fly this sucker this weekend if the weather is good enough.

Time spent today 5.5 hours total time so far 75 hours.

Riviting the Cowling Piano Hinge

Tonight I finished up the major construction on the cowling by riviting the piano hinges to the cowling.  I started by setting up the countersink and countersinking the fiberglass.  I borrowed a friends pneumatic squeezer to squeeze the rivits.  That helped a ton and my hands thanked me for not having to hand sqeeze all those rivits. I re-installed the cowling and it looks great.  Just before I installed the cowling I made a template to mark the location of the dipstick door.  I traced it onto the cowling after install and when I have some time I will cut it out and install an aluminum door using some spare piano hinge.  All in all a good day

Time spent 2.5 hours total time spent 69.5 hours

Mounting the Cowling Permenently

Today I started off by trimming the spinner back about 3/16 – 1/4″ to help leave a gap between the cowling and the spinner.  I then set off to mount the cowling permanently.  I already have nut plates and holes drilled on the firewall so I needed to transfer them to the cowling.  The only way I can do with is all at once.  So I made 31 transfer tools out of aluminum strips with a rivit on each end and holes drilled on the other side.  I then used a flush screw to hold the transfer tools in each nut plate and use the top side of the transfer tools as a guide for my drill.  I drilled all 31 holes and then countersunk each of them for the tinnerman washers.  This took quite a while once completed the cowling was nice and strong and sitting perfectly where it should with the perfect gap between the spinner and the cowling.  In the last picture I have some paint touch up work to do taking this cowling on and off 100 time I had scratched the paint a little.  Lets be honest with my cowling to paint, my wheel pants to paint, gear legs to paint.  I have some painting projects .

Time spent today 7 hours total time spent 67 hours