Archive for the ‘Finish Stages’ Category

Canopy Cover, Certificate Display, HSR Fly-in

Taking inspiration from my friend with the Sidewinder, I decided I needed a snap-on canopy cover for overnight trips. I had an old grey Evolution II car cover up in the attic from a Saab 900T I sold about 15 years ago. It was in reasonably good shape, so my Mom and I cannibalized it and fabricated a canopy cover. My Mom’s been sewing for 60 years so this is well within her comfort zone. I know more about sewing and sewing terms than any straight guy should ever know simply from listening to my mother talk about it for almost 42 years!

The regs require the Airworthiness Certificate to be “displayed.” The original builder of my airframe installed a manual trim system that required 4 holes in the side of the fuselage for the trim lever mechanism. Since I switched to electric trim as part of my refurbishment, I had 4 extra holes in the side of my fuselage that weren’t being used for anything. I purchased a scrap piece of plexiglass, cut it to size, beveled the edges and then attached it using the pre-existing holes and a few acorn nuts. Looks pretty danged clean if I do say so myself.

This is the famous and always-entertaining Larry Vetterman of Vetterman exhausts. Larry’s company supplies exhaust systems to a large majority of the Van’s Aircraft community. He hosted a fly-in at his home airport in Hot Springs, SD on the weekend of September 10th. I hoped to talk him into doing an exhaust system for my Midget Mustang, but he doesn’t have any of the tooling to work with the 1-1/2″ pipe on an O-200. Bummer.

The winds in Hot Springs (KHSR) were predicted to be a factor so I made it a point to get up there early on Friday. I was the first to arrive and scored a free T-Shirt from last year’s fly-in! There were 50-something RV’s in attendance and a whopping 3 “other” flavors of aircraft. I felt a bit like a turd in a punchbowl! The Midget Mustang made the RV’s look like they are huge aircraft. Speaks more to the size of the Midget Mustang, not the size of the RV’s.

There is a huge archeological Wooly Mammoth dig going on in Hot Springs. They are constructing this statue to honor the Wooly Mammoth at the top of a hill as you head out of town towards the airport. It reminds me of something you’d see in a Monty Python movie! Makes me smile every time I see this picture.

Larry came up with this self-guided aerial tour of South Dakota for the fly-in participants. Pilot briefings were held every 30 minutes or so most of the day on Saturday and folks took off in groups of 3-5 airplanes to follow the trail. After visiting Mt. Rushmore, Crazy Horse, Devil’s Tower and Sturgis, the group landed in Wall, SD and went to Wall Drug for lunch. After that, they cruised through the South Dakota “badlands” area before returning to Hot Springs. My allergies were killing me so I left early and didn’t do the tour.
I’ll probably head back up to HSR some nice day to do the aerial tour. It looked like fun.
As I departed HSR to head back to Loveland, I experienced a drastic loss of oil pressure. It was a cool morning with a short taxi so I had to wait for my oil temperature to get above the minimum 75 degrees for takeoff. I took off when the temp was showing approximately 90 degrees.
A few minutes later as I was circling overhead trying to decide if I wanted to go fly by Mt. Rushmore before heading home, I noticed that my oil pressure had dropped to 15psi. Ruh roh.
I made an immediate landing. It wasn’t pretty, but I was back on the ground and the engine was at idle. With the help of all the great people at the fly-in, we removed my oil screen and the pressure relief valve. I found a small aluminum shaving in the pressure relieve valve housing that must have kept the valve from sealing when the oil temperature got above 100 degrees or so.
We didn’t find anything at all in the screen so everyone agreed that I was safe to fly it home if it made pressure.
This is the second time I’ve found aluminum shavings in my pressure relief valve housing. I’m about 95% certain that the aluminum shavings are entirely the result of my own stupidity in not making it a point to plug my spark plug holes when I was installing and drilling the sidewalls of my engine baffling. I thought I was being careful, but these shavings look suspiciously like shavings from a #40 drill bit making holes in .032″ aluminum!
I took off from HSR and circled overhead until the oil temperature was at 180 degrees. The pressure was holding rock steady at 45-50psi so I headed for home.

Oil Cooler and More Photos

I test-flew the oil cooler installation on 07-16-10 to get an idea of how well this setup was going to work. It lowered my oil temps by a solid 25-30 degrees! Success, as far as I’m concerned. I still needed to plug the gap between my diffuser box and the oil cooler fins. I applied vinyl tape and some Part-All mold release to my diffuser box.

I then attached the diffuser box to the oil cooler and applied some black RTV to fill the voids.

The next morning, before flying the plane again, I took it all apart and removed the tape. What was left was sort of a crude-looking custom gasket. I think I can make this look prettier, but that will have to wait until I do the finish work on the plenum itself. I’m having too much fun flying to make stuff like this look real purty.

After a fantastic 1.2 hour flight on 07-18-10, I decided it was time for a few photos. This is one of my favorite viewing angles for the Midget Mustang. I just love the shape from an overhead view. I’ll have to find a little better lighting the next time I do this.

I think this is the first time I’ve posted a picture of my panel with all the labels applied. Aerographics made the labels for me. I think they did a fantastic job. If you look on the GPS, you can see my track line for the first 5 flights. Lots of laps over the top of the airfield!

As I mentioned above, today’s flight lasted 1.2 hours on the Hobbs meter. The temps were under control and I finally felt confident enough to leave the pattern long enough for some steep turns and a few stalls. I’m very happy to say that it stalls clean, power off at 70 mph indicated. Each notch of flaps lowers the stall speed approximately 3-4 mph with the full-flaps stall occurring at 58 mph indicated. MUCH better now than before the rebuild.

The stalls also broke straight ahead with plenty of warning in the form of reduced control effectiveness and a gentle buffet. Recovery was immediate by reducing back pressure and applying power. I also did a few 90 degree banks and rolled rapidly from 90 degrees left to 90 degrees right. Wow! This thing is wicked quick in roll. I banged my head on the first one. I’ll have to work hard to learn to NOT introduce a pitch input when rolling left/right. The elevator is very sensitive.

I wanted to put in a plug for these nav lights. I’ll have to update this post to include detailed information about manufacturer, but I’ve been really happy with these little lights. They’re obviously LED and also have a strobe light. There’s a single power pack for the strobes which I have mounted under my baggage floor. The wingtip lights are VERY lightweight at something like 11 ounces. I modified the wingtips to include a mounting base for the lights.

I’ve probably already got a picture of this somewhere, but here’s a shot of my cockpit lighting installation. The row of blue lights on the canopy provides just the right glow to see the instruments at night. The good news is that there’s a lip of plexiglass from the canopy that shields the pilots eyes from the strip lights themselves. All you see from the pilot’s perspective is the glow from the lights, not the lights themselves.

I’m away from home at work this week from Monday through Wednesday. I’m hoping to fly again this Thursday and Friday. I’d like to do some touch and go’s to make sure I can land this thing in a reasonable distance. I made 4 landings this morning using an over-the-fence speed of about 90 mph. I think with a little more confidence, I’ll drop that to 80-85 mph. The plane was very controllable at that speed and still had plenty of energy for a flare and a little float. I did 2 wheel landings and 2 3-point landings. They were all very controlled and the plane showed no signs of darting in any particular direction.

If all goes well, I’m planning to fly up to Mitchell, SD this weekend to hang out with the Air Venture Cup racers. I’ll spend the night in Mitchell on Saturday, watch the race start on Sunday morning and then head home before noon on Sunday. I’ve got a little bit of vacation time at the end of this month that I had planned to use for an Oshkosh visit, but since that’s not going to happen, I’ll probably just get to work installing wheelpants and fabricating my aux. tank. I’d like to participate in a few of the SARL races this year.

Oil Cooler

Here is the assembly with the front half of the tubing bonded in place and sanded lightly. I’ll install it and test fly it before doing any finish work.

Here it is installed on the engine. I’ll need to plug some holes at the oil cooler with a little RTV, but other than that, it fits perfectly. I’d rather not have the air change directions so much and so abruptly, but everything’s a compromise so we’ll just see how this works.

You can see how the oil cooler ducting has a separate intake within the cowling intake. I haven’t measured it, but my highly-calibrated eyeball says it’s a little over 1 square inch of intake area.

I re-routed the 1/8″ copper line for my manifold pressure transducer to go under the oil cooler hoses rather than over the hoses. There was clearance before, but I was afraid the heavy hose might sag in time and put pressure on the copper tubing. Copper tubing has a tendency to crack anyway. No since in irritating it unnecessarily.

You know what they say about guys with big feet… They don’t fit too well in little, tiny airplanes. The sneaker on the left is my standard work at the shop shoe. I purchased the Simpson racing shoes on the right because they are far less cumbersome when flying my little plane. It’s amazing how much difference a quarter inch here and there can make when fumbling for the rudder pedals.

Oil Cooler Intake

Through a strange twist of events at work today, I ended up with the evening off. I have to go back to work first thing in the morning, but I took a little field trip out to the hangar this evening before bed and removed all the masking paper from yesterday’s fiberglass session.

Here’s the assembly looking at it from back to front. I haven’t separated the new piece from the original cylinder plenum pieces, yet. I’m thinking I may use industrial strength velcro to attach the oil cooler tubes to the cylinder plenum pieces. It’d be secure, yet removable when necessary.

The new piece separated from the plenum. You can see the clay and the PVC pipe through the translucent fiberglass.

I trimmed a few of the sharp, pointy edges and then cut the part down the middle, lengthwise. I’ll dig out the clay and remove the pipe sections which should leave a fairly clean piece.

Here are the two halves laying on a work table. They’ll need a fair bit of clean-up and several more sessions of glass before I’m ready to join the two halves permanently. When I did the initial fiberglass layup, my intention was not to achieve final thickness or strength. My goal was to get enough glass on the mold so that it would hold a shape and allow me to put the finishing touches on from both the inside and the outside. It is turning out very well as far as I’m concerned.

I’m excited to move on to the next stage of layup on this piece, but I have to go to work tomorrow morning, early, until Thursday afternoon. I’m off from Friday through Sunday this week so I’ll try to make a bunch of progress at that time. Now that I’ve flown the airplane, I can’t stand the thought of NOT flying it again very soon!

Oil Cooler Intake Air

I removed the cylinder plenum covers along with the new oil cooler intake plumbing as a single piece. I used mold release between the new fiberglass and the cylinder plenum, but I did my best not to separate the parts in hopes of glassing the underside of the oil cooler intake today with the whole thing turned upside down on my workbench. It’s a whole lot easier to apply resin to fiberglass cloth when gravity isn’t working against you!

There were a few drips of resin on my clay mold leftover from yesterday’s layup. I picked them off with my fingernail and applied a little additional clay and a little additional mold release. I also noticed a few spots where I could have done a better job with my clay work so I futzed around with that a little, too.

Here’s the way I left the part when I was finished working today. I laid up 3-4 layers over everything. I did my best to smooth out the edges so there wouldn’t be any jaggies, but I’m sure it’ll take some sanding before it’s smooth. My plan is to split the intake in two pieces to break it free from the mold. I’ll then bond the pieces back together using a combination of resin, flox, and a few strips of glass cloth. I’m sure I’ll also be doing some finish work around the edges from the inside of the intake before I glue it back together. There is a bunch of work left to be done.

I’m headed to work tomorrow morning at Oh-dark-thirty. I really should be in bed asleep right now, but the noise from all the fireworks is keeping me up anyway so I figured I’d make this post. I live in a neighborhood full of 60+ year-old, wealthy retired folks. I can’t believe the fireworks these crazy old buggers have! They must have made a bootleg run up to Wyoming because most of the stuff I’m hearing and watching from my back porch is illegal in Colorado!

Good for them, I say. We are supposed to be celebrating INDEPENDENCE day, right? Life, liberty and the pursuit of happiness, right? Freedom? Seems like there’s less and less of all of the above every day.

More Oil Cooler & Fresh Air Intake

I finished fabricating the oil cooler hoses this morning. I read an internet post recently where someone said he considered the orange fire sleeved hoses ugly. I think they look pretty cool, actually. I think it’s worth it to buy the proper stainless steel bands and the banding tool rather than using safety wire. I also whip up my own firesleeve dip by mixing high temp RTV with lacquer thinner. I made a post showing how to do this a few months ago. It works great, looks great and costs a fraction of the real deal dip.

The hoses installed looking from the right side of the engine. I did a brief engine run with my EAA tech counselor standing by to watch for any leaks. Good news. No leaks. I’ll need to spend a little time tying the hoses down and doing a little chafe protection before I fly the airplane again.

I bought this nifty little tool from Harbor Freight for less than $40. it cuts through fiberglass like butter and because it vibrates rather than spinning, it hardly throws any dust at all. Wish I would have discovered this much earlier in my project. I cut a block of foam and glued it to a flat 3-ply sheet of fiberglass I had laying around from a previous project. This will be the starting point for my oil cooler cold air inlet plumbing.

I rounded the corners of the foam block and then attached it to the face of my oil cooler. I bought a 1-1/2 foot length of 1-1/2″ PVC pipe from Home Depot. I’ll use the pipe as a mold for my fiberglass cold air intake system.

I used modeling clay to make the transitions from the PVC pipe to the foam block and to my cylinder intake plenum. I put a thin coat of clay over the foam block. With a little mold release on the clay, it leaves a very nice, smooth finish after the layup cures and the clay is removed.

A birds-eye view of the cold air intake system. If necessary, I can add a few vanes inside the plenum intake to direct air to the cooler. I think it’ll get there without the vanes, but I guess it’ll be a matter of degree–as in how many degrees the setup lowers my oil temperatures!

I covered all the clay and the PVC pipe with Part-All wax/mold release. I then laid up 2-3 layers of 6 oz. cloth over the mold. Since it would be somewhere between difficult and impossible to layup all sides of the mold with it still attached to the engine, I decided to do what I could and then finish the layup with the parts on my workbench. I’m hoping I did enough glass work today to solidify the shape so that I can remove it from the engine and finish the layup tomorrow.

Oil Cooler Installation

Here is the Stewart Warner 5-row oil cooler I purchased used. I’ve installed the AN6 right-angle fittings in this picture. I picked up the cooler from the local radiator shop earlier today. They cleaned and leak-checked it. The guy said there was a little debris, but not much at all. It passed the leak check with no problems. The guy commented that he’s not used to seeing a small cooler built so stout! Since they’re a radiator shop, they used coolant to flush the oil cooler. I didn’t want to take a chance of contaminating my engine oil so I first blew the cooler out with compressed air and then I filled it and flushed it with Phillips X/C three times to make sure the only thing left inside was oil! I’ve been very careful to keep it plugged to avoid contamination after the oil flushing process.

I removed this piece from the engine case to install a special bracket in its place to give an in-out port for the oil cooler hoses. This is also where an oil cooler adapter or remote mount kit would be installed.

This is the special adapter to allow for oil cooler in and out ports for the oil cooler hoses. I was told this piece was manufactured by Ib Hansen of Cassutt fame in the Denver area. I haven’t seen Ib in more than 10 years so I haven’t asked him if this is really his part.

Here are the new oil cooler hoses nearing completion. I’m using Aeroquip 303 hose with the 491 ends and Aeroquip firesleeve held in place with stainless bands. These things weren’t cheap, but I’ll feel better knowing I’ve taken all reasonable precautions against an engine compartment fire. I’m thinking the oil cooler setup will probably add 5-7 pounds to my empty weight. The oil cooler itself only weighed 1lb.13oz., but these hose assemblies aren’t light! In all honestly, I could probably use a little more weight forward of the CG anyway, so I’m not too upset at the additional weight.

I’ll probably finish the hoses and install everything tomorrow for a quick engine run to confirm that everything is flowing and not leaking. I may or may not fly the plane again to see if I see any improvement with just the oil cooler installed and no fresh air ducting blowing through the cooler. I’m still waffling on doing this because it’s probably a waste of time. It stands to reason that I need to duct some cool, fresh air through the cooler or it’s not gonna do much. Maybe if I can find a time when the OAT is cool and the winds are calm…

Oil Cooler

I spent what little time I had available on Monday fabricating mounting brackets for the oil cooler. It’s crazy how much time this little stuff can take. Here are the brackets installed temporarily to check the fit. I’ll need to visit the aviation aisle at Ace to pick up some slightly longer case bolts to accommodate the thickness of the new brackets.

This is the front side of the cooler. I mounted nutplates in the new brackets and used 8-32 panhead screws to hold the cooler in place.

This is the outlet side of the oil cooler. The depth of the oil cooler worked out that in this case, I drilled holes in the brackets and installed a couple of nutplates in the oil cooler flange. There were already holes drilled for nutplates in the flange from a previous installation so all I had to do was clean out the silicone caulking and do a slight touch-up on the machine countersinking.

After the installation, I once-again verified the clearance by installing the upper cowl and using this piece of angle between the firewall and the spinner. Nothing rubs!

I left the hangar a few minutes early this afternoon so that I could drop off the cooler at the local radiator shop before they closed for the evening. I’ll pick it up Friday morning when I get back to town. I figure it’s worth spending a few bucks having it checked out and cleaned. It’d be a shame to have engine problems due to a problem with the oil cooler.

The next big task will be creating a fiberglass diffuser box and tubes to come off the front end of the cylinder plenum. I’ll probably get started with that on Friday. I ordered another few feet of Aeroquip 303 hose and firesleeve to fabricate the additional oil lines. Man, that stuff isn’t cheap! By the time all’s said and done, I’ll have a total of about $150 in 2 30-inch hoses!

2nd Flight & Oil Cooler

After talking with my engine rebuilder, I decided I may have been a little too conservative regarding my oil temperature on the first flight. I decided to try another flight before taking measures to mitigate the “problem.” Yesterday morning provided nearly ideal conditions for a 2nd flight. The winds were calm, the skies were clear and the temperature was a very mild 70 degrees. The airplane flew beautifully, but the oil temperature was even higher. I landed as the oil temp reached 240 degrees. I called a few friends to see if anyone could suggest a local source for an oil cooler.

A friend of a friend had this 5-row Stewart Warner cooler laying around his workshop collecting dust. He agreed to sell it to me at a very reasonable price. After receiving an email from another Midget Mustang builder, I’ve decided to try mounting the oil cooler on top of the case.

I fabricated these brackets using some scrap aluminum angle I had laying around my shop. I’ll need 4 of these in this same basic shape. These will hold the forward edge of the cooler.

With the cooler bolted into place, I installed the upper cowling to check for clearance. I couldn’t feel anything touching even when I banged on the top of the cowling. I also used this piece of aluminum angle to verify the clearance. Looks like I’ll be in good shape.

Unfortunately, I have a few outside commitments this afternoon so I had to quit out at the hangar by a little after noon. Depending on how things go, I may make it back to the hangar later this evening. If not, I should be able to spend most of the day tomorrow working on this project.

First Flight

At approximately 9:15am Mountain Daylight Time on June 20, 2010, N881MM took to the skies. I made about 6 laps around the pattern and called it a day. The oil temperature was creeping higher and higher and I wanted to stop to investigate. After talking with the engine guy, I will do 1-2 more flights before considering an oil cooler. I don’t mind adding a cooler, but don’t want to unnecessarily add weight and complexity if my oil temp issue is simply a matter of breaking in a new engine.
The only other real squawk is that I managed to wire my electric trim backwards so that UP is DOWN and DOWN is UP. Woops. Luckily, the plane has very good control authority and trim is a luxury item, not a necessity. The situation is easily corrected by reversing two wires at the control servo.
I achieved 2100 rpm in a full power static run-up just before launching. I was climbing at 90-95 mph indicated at about 8-900 feet per minute. The density altitude at field elevation was 6400′. It was a relatively cool morning.
I’m not real current in small airplanes or taildraggers so I planned to use all of our 8500′ runway. I pretty much did. Again, more of a luxury than a necessity. The plane seemed to track nice and straight. It was sensitive, but in a good way, not a twitchy way.
I left the power in on one long leg and let the plane accelerate to an indicated 145 mph. I didn’t think to look at my GPS for a ground speed, but a post flight check of the GPS history showed a max ground speed of 167 mph. Given almost calm winds and a density altitude of approximately 7500′, my groundspeed was pretty close to my true airspeed. I’m satisfied that my airspeed indicator is fairly accurate at that airspeed.
I have to go to work this evening, but I’ll be back tomorrow morning. If the weather cooperates, I’m hoping for a second flight tomorrow night before I leave for a 4-day trip on Tuesday morning.
If I don’t have any additional problems, I think I’ll be able to make it to Oshkosh this year. I still need to fabricate an auxiliary fuel tank, install wheel pants and possibly install an oil cooler. I’m sure the next 4 weeks will pass quickly!