Sunday, December 14, 2008

We are nearing Christmas and things have been busy for our family. The only activity on my Midget Mustang has been to explore the spin characteristics of the plane by corresponding with another Midget flyer who regularly spins his plane, as well as doing other aerobatics. His experience will help me greatly when I finally get back into the air. As it turns out, the plane enters spins easily using standard spin entry techniques, but the recovery is a little different. Instead of using full opposite rudder, the Midget requires just enough opposite rudder to stop the rotation. Full deflection will flip the plane into a spin in the opposite direction. In addition, spinning over 3 turns is not recommended because the spin gets very fast. Our weather here is fine for this time of the year, but we have about 7" of snow on the ground and runway. There will be no flying for awhile. I couldn't even get to the runway to take a picture, but you can see what our house looked like.

Wednesday, November 5, 2008

Yesterday I finished up my required 40 hours. I could sign off the Phase I and II requirements if I choose, but I still have a few other things to do. I also worked thru some aerobatics. Earlier I had done aileron rolls, which require little except raising the nose and then applying aileron (and rudder to center the ball) to roll the plane all the way around. As the plane rolls about the longitudional axis, the nose falls. To lessen this effect, I go to about .5 G as the airplane starts into the inverted portion of the roll.

Loops, Cuban Eights, Barrel Rolls, the Split S and Immelman Turns are more fun. For several flights I explored the vertical capability going up and down, but I never did a good vertical figure. Yesterday I finally put it all together and did some good loops and other figures by diving to 200 mph, pulling up wings level at about 3 G until the airspeed died away, going over the top inverted with about 85 mph. For loops, it was easy to just continue down the other side increasing backstick pressure to create a little over 2 G as the plane accelerated to about 180 mph. The whole thing happens fairly quickly. I was surprised at how well behaved the plane was thru the whole thing. It seems to like to do this stuff and does it without straining.

Sunday, November 2, 2008

Now I have a little over 38 hours on the Midget, and must get to 40 hours to meet the minimum FAA certification requirements. Most of the problems have been minor and were solved. There were only 2 problems which required any amount of time to work thru. The first was that it seemed like the plane required too much runway for the takeoff. My static engine rpm was 2200 rpm with my original prop. I installed a slightly larger carb, but that only improved things incrementally. Eventually I installed a different prop and that enabled the engine to run at 2500 rpm. The performance may have improved, but not a lot. Well, in the end, it appears the engine was doing what was expected from day one. Part of the problem was poor technique on my part and the other part was unrealistic expectations. I still can't get the plane off in the distances others claim, but I am getting closer. Most say it should get off the ground in less than 1000'. My best is about 1000', but in general it takes me about 1200'. Maybe I will get better, who knows...

My takeoff technique is to line up on the runway center line with 1 notch of flaps (15 degrees on a grass runway), make sure the tailwheel is centered, release the brakes, go to full power, let the tail remain on the ground until the airspeed reaches 40 mph, then raise the tail. If I raise the tail more quickly, it is sometimes difficult to overcome the tendency of the prop wash to force the plane to the left. As the plane accelerates I set the takeoff attitude and wait for the plane to flyoff the runway. It normally leaves the ground at about 60 mph indicated and accelerates fairly quickly to 75 mph. I raise the flaps at 80 mph and climb at 100 mph indicated with full available power. The plane is well behaved, but definately needs managed during the takeoff roll. Cross winds from the left are naturally more troublesome.

The second problem was that my oil temperature runs higher than I would like. This is fairly common for homebuilts that are tightly cowled. My Midget Mustang is tightly cowled, so after determining that I would need to deal with high oil temperature, I added an oil cooler. After some tinkering, I have managed to get enough air flowing thru the cooler to enable it to cool the oil by up to 16 degrees F. Generally I see at least 10 degrees F of cooling thru the oil cooler. I will continue to work thru this problem. At the current time I pipe air from the cowl inlet directly to the oil cooler thru a 1.5" scat tube. The exhaust of the oil cooler is directed into the cockpit for heat as the fall days are getting cooler and I need some heat in the cockpit. The exhaust hose is 2" scat tubing. The temperature of the air exiting the oil cooler is about 10 to 20 degrees F below the oil temperature. Thus the air entering the cockpit is about 160-180 degrees. The temperatures are measured via termisters and thermocouples and are fairly accurate. I will continue to work on this situation.

Some of the minor things I have worked on include: brake o-ring replacement; a transponder that works ok in Mode A, but will not do Mode C; the failure of the regulator in my standby B&C SD-8 alternator system; a minor fuel leak in the header tank, and a minor adjustment to my cable actuated starter system.

Stalls are uneventful if you ease into them slowly. There is a warning at about 2 mph before the stall. I would describe the warning as a high pitched vibration that I more hear than feel. The plane may fall off on either wing during the stall, but it is not all that excuiting. I generally loose about 200-300 feet of altitude. Pulling into the stall more agressively means the stall will be much sharper and the nose will fall further during the recovery. Speed builds quickly when the nose falls, so stalls with flaps down require some care. I have not done accelerated stall yet.

The plane is well behaved in the landing pattern. I generally fly the downwind leg at 100 mph. Abeam the touchdown point, I lower the flaps 2 notches (out of three total) and slow to 85 mph. I hold 85 until I turn final, where I go to full flaps and 75 mph. Crossing the threshold at 70 works well, but 75 is good too. Once the plane is slowed to 75 mph on final, the runway is no longer visible. My best landings are when I gently over-rotate to touch the tailwheel first. In that case the mains come down softly and stay on the ground. If I touch down in a three point attitude, the plane is not done flying and tends to bounce a little. Touchdowns at 60 mph work out well. Once the tail is on the ground I bring the stick to its aft limit. The plane seems to roll out straight with small rudder inputs during the initial landing roll. As the airspeed decreases, it passes thru a band where more attention is required.

As a summary to this post, the plane and I are getting along well together. It is fun to fly and the freedom to be inverted is great. I had forgotten how good it is to sit on the centerline. My canopy does not have a canopy bow, so the view is absolutely wonderful. It is not my intention to sign off theFAA certification until I complete the aerobatics on my list. At this point, I am extremely impressed at how well everything works. There have been very few failures and everything is working as designed.

Thursday, July 10, 2008

Background Info

My airplane building career started back in the early 1960's while I was in the Navy and stationed in the San Diego, CA area. I sent away for the plans to build a Midget Mustang The plane was designed by David Long following WWII. At that time the plans were maintained and sold by Bob Bushby. I started making small parts and completed all the wing ribs and welded fittings before I left the Navy. At that time there were no kit planes available, so everything was built from plans.

After I left the Navy, life got busy. I started a new career working as an engineer with a pretty wife, two great children and all the associated responsibilities. The airplane parts ended up in a corner of the basement. Except of one small venture, that was the end of my aircraft building. The venture was that I learned about Jim Bede's BD-5. Jim was selling a completed airplane and I thought it would be a great plane to own and fly so I put a deposit down and hoped for the best. My hopes were in vain and Jim was never able to deliver on his promise, although there are several jet powered versions of the BD-5 flying today.

Aviation was deep in my blood. I rented planes and bummed flights with friends. I flew a hang glider and several of the earliest ultralights, but when my daughter said she wanted to learn to fly ultralights, I thought it was time to go a different route. I bought an old Cessna 150 in 1982 and flew it for more than 2 years thinking it would be a great plane for her to learn to fly. In the mean time, she discovered boys and lost her interest in flying. I wanted to sell the 150 and buy a Pitts Special, but my family thought a Cessna 182 would be a better choice, so I purchased a half share in a Skylane. That was one of the best moves I ever made. We still own and fly that fine plane and after good experiences with three partners, we now own it solo.

Now fast forward to the fall of 2002. My son was interested in finding a plane to build and eventually settled on the Midget Mustang. He suggested I finish mine and that's how my plane building project was restarted. Thanks Brad... :-)

Construction started in the summer of 2003. The plane was built from a kit supplied by Mustang Aero, which is operated by Chris Tieman. They do a great job and are as helpful as can be expected. The building process was challenging, fun and satisfying. The plans covered the metal part of the plane and some of the systems, but I set out to build a high-tech aircraft so I was sort of on my own for all that stuff. The construction phase took about 4 years of calendar time and about 2200 hours of build time. The plane was moved from our house to the airport on July 23, 2007 (my wedding anniversary).

The plane I had built was equipped with a tailwheel. All the other planes I had flown had nose wheels. Planes with nose wheels are much easier to takeoff and land than planes with tailwheels. I prepared as best as I could to fly a tail dragger. I got certified in the famous old yellow Piper Cub. That was important, but the Cub was too easy to fly to enable me to fly the Midget. I got training in a Citabria, but it too was too easy. I flew a Pitts Special, but it was way to hard to learn enough with the money I had available for training. Lastly, I flew a Piper Pacer for an hour or so. All in all, I had a good idea of what had to be done, so I started running the Midget up and down the runway with the tail in the air. Eventually, after 100+ runs, I got the "hang of it". After that, it was time to find a day with good weather and light winds.

The first flight was October 4, 2007 (10/4 is the way I remember that date). It was executing flying an airplane that I built with my own two hands. I was sure it was going to fly, but at the same time, I wondered if I had done everything correctly. And then there was the nagging problem of would I be able to land the plane. I had done lots of runs up and down the runway, but I had never really landed it. As it turns out, everything went well and the plane flew fine. It was much more sensitive than my Cessna 182 (which most people say flys like a truck), but it was fun. A friend on the ground kept me focused on things like oil pressure and temperature and other stuff like that. I entered the landing pattern with the idea that I would make a couple of practice approaches, then try a landing. As I entered the landing flare everything looked so good I just landed and rolled out. I smiled for two days.

So far I have 14 hours of flight time logged and things are going as expected. I am still debugging problems, but everything is moving forward nicely. I'll tell you more about the building process and the flight testing in future posts.