Archive for July, 2010

Flying Report

I’ve been flying the wings off my Midget Mustang over the past week or so. As of this morning, I now have 12.8 hours on the Hobbs.

I’m starting to get comfortable with light airplane flying again. My approaches are much more consistent and my landings are improving nicely. I can now do a wheel or 3-point landing whenever I want and my landing distance is down to a more reasonable level.

This morning I went out with the intention of getting a baseline for speed improvements. Right now, I’ve got an aileron that’s slightly out of rig–which then brings about a need for a little rudder trim adjustment. I don’t have the wheelpants installed, either. I want to be able to quantify the improvements as I start cleaning things up so I made a few full-power runs at approximately 8000′ density altitude.

I’ve got a spreadsheet where you plug in your groundspeed and track on three different tracks. The spreadsheet does the trig calculations and poops out True Airspeed and the calculated wind direction and speed. I took measurements from 6 different tracks. I let the airplane accelerate as much as it could and carefully held heading and altitude while making sure the airplane was in coordinated flight. I plugged all the results into my spreadsheet and came up with consistent results… I’m doing 175 mph True Airspeed at this time.

I’m bummed because I was really hoping I’d be closer to 200 mph. Oh well, it *is* just an O200, after all. Maybe the wheel pants will work miracles.

I’ve been keeping close track of my fuel burn and the amount added at each fillup. I’m using self-serve fuel farms so the fill-ups have been to a consistent level. I’ve got a JPI fuel flow computer so I’ve been slowly tweaking the “K-factor” to achieve accuracy. As of this morning, it looks like I’m within 3-tenths. I’m really happy with its performance.

I spent $50 updating my Garmin 496 Nav database. I’ve decided I’ll probably just do it once a year. I really like the 496 and its various alert functions. It’s alerted me a couple of times as I approached a few of the widow-maker antennas in the local area. I’m pretty careful about knowing where they are, but it’s reassuring to hear the alerts, too.

I’m a little shocked at how long my takeoff rolls are. It’s taking me about 2500′ before the plane is ready to fly. My latest technique is to get the tail up as soon as I can to improve ground control and visibility. It’s really not ready to fly until about 80mph so I’m holding it on until I see at least 80-85. In fairness, the lowest density altitude I’ve seen is about 6300′. I’m sure my swerving around is soaking up a little takeoff energy!

I may have to do something different with my comm antenna. I’ve got a stainless steel bent antenna under the belly. It’s bent at about a 70 degree angle. I’ll look through the photos section to get an idea of what others are doing, but I’d also love to hear of any sure-fire solutions, too. My XCOM radio is one firmware revision behind, so that may have something to do with my poor radio performance, too. A friend bought me a Zulu headset at Oshkosh yesterday, too, so I’ll get everything else sorted out and then start jacking with the antenna.

All-in-all, I’m enjoying this phase of the game. I’m finally starting to trust the plane and no longer pucker up each time I’m more than gliding distance from the airport. I should have some decent air-to-air photos to share by the end of the week. A friend and his wife took 200 pictures from their RV-6. He left for Oshkosh without emailing the pictures so I’ll have to wait until he gets back to town to see the results of the photo mission.

Yes, my posts are long. I guess that’s what happens when you type 60 wpm and you’re excited about a new toy!

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.

Airport Open House

My home airport in Loveland (Fort Collins-Loveland Municipal–KFNL) had an open house on the weekend of July 10. The Collings Foundation came to town with their B-17, B-24 and P-51. The excitement drew a few of our own local warbird types. It was a great photo op for me. With the permission of their owners, I drug my airplane out of the hangar and posed it with the various airplanes. This is Joe Thibodeau’s Sea Fury. Joe is a tax attorney in the Denver area. He’s also got a P-51, but he can only fly one plane at a time!

This T-6 is owned by a guy from Denver and was being flown by a friend of mine from work. The T-6 isn’t considered a huge airplane, but you can see it’s significantly bigger than a Midget Mustang.

This one really shows the size of a Midget Mustang. It almost looks like a scale RC model sitting between the 2 T-6’s.

The big one and the little one pose for a photo. I imagine opportunities like this won’t come along too often. It was pretty cool to be allowed to do this. This is probably the best picture I have of my airplane so far.

Oil Cooler & Aux Tank

With easy access to the inside of the oil cooler ducting, I used a little clay to radius the corners of the box. This is a pretty simple layout, but it still takes time because once you place the glass, you’ve got to wait a day or so for everything to cure.

Once I was pretty happy with how the diffuser box was going to mount to the oil cooler, it was time to bond the tubes to the cylinder intake plenum. I had originally considered making the tubes detachable from the plenum, but decided this wasn’t necessary.

Since the front half of the assembly hasn’t been bonded into place, I took advantage of the good access and applied a few layers of cloth to smooth the opening.

I decided to continue the tube to the front of the intake plenum to make sure the cooler received plenty of air. I used modeling clay to establish the shape.

It was a little difficult applying cloth and resin to the inside of the cavity, but you can see in this picture with the clay mold removed, it actually came out pretty good.

I made extensive use of my Dremel tool with the cone-shaped grinding stone attachment to smooth the rough edges of the fiberglass layup. With this portion completed, my next goal will be to join the front half of the intake to the rear half.

Keeping in mind that all of the stuff I’ve described above happened over the course of a few days, I’ve always found that it’s good to have something else to be working on while you’re waiting for resin to cure. I decided to start working on my auxiliary/ferry fuel tank. This is the big block of foam I started with.

I cut the big block of foam to the approximate size and shape and then added a few pieces along the edge to minimize the amount of filler I’d have to use to achieve the final desired shape. I glued the block of foam to the seatback so that I could test-fit the seatback to make sure everything fit.

Once the block of foam had been sanded to final size and shape, I applied Bondo to the foam. Bondo sands well and can be painted. My standard practice is to finish the Bondo as if it were going to be the finished piece. I sand and fill all the imperfections and then paint the Bondo so that (a) the fiberglass will release easier from the mold and (b) the finished surface of the fiberglass part will be very nice right out of the mold–minimal, if any, sanding.

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…