The other day I accidentally cut deeply into my index finger. After the heavy bleeding had stopped I was left with a gaping cut that hurt for two days. But soon after the wound started to close and to heal. It always amazes me how the body “remembers” what cells to grow when healing a wound. It’s a miracle to me. After just one week the cut is completely closed and pain free. How does the body do that? Engineering hasn’t managed anything as remarkable as the self healing capabilities of our bodies.

This week-end we finally had a calm day with almost no wind that enabled me to fly my model airplane – a very light styrofoam park flyer with two electrical engines. I fly this 90cm wing span plane from the water retention pond in our neighborhood. That is big enough to fly big circles and get it down to land.

I had charged the batteries and was quite excited about the flight. After take-off there even was a turkey vulture soaring right above me. So I flew the little plane over and we started thermalling together. How exciting, I thought to myself. I could shut down the engine and the plane stayed nicely in the turn, climbing with the bird. The wind picked up with altitude and the bird was drifting away in the thermal bubble – along with my airplane. So I decided to fly back towards my location, but every time I levelled off to fly towards me I was hit by a huge gust at the boundary of the thermal. The plane kept climbing and I already had a hard time judging its position half of the time. I eventually became a little more desperate, realizing that the wind and time were working against me and the little plane kept climbing with no power.I banked it hard and it gyroed violently in the sky, descending in big dives. I stabilized it over the tree tops, barely able to see the plane, that must have been 1/4 mile away by now. I applied cruise power and took a guess of the flight direction. It turned out to be the wrong direction, and shortly after that realization the plane disappeared on the horizon. My spirits sunk, realizing that I had just lost my model airplane. I listened quietly for about 2 minutes, trying to hear the “landing” to no avail. After a short deflated moment, I picked myself up, telling myself what a cool flight this has been for the last 15 min while walking back to the car. I figured I’d drive the neighborhood in the hope that I would find the plane – what are the odds?. So I cruised around for ~10 min. and just before I wanted to quit, I come around a corner with a lot of kids playing in front of their house. And sure enough there was my model airplane sitting in the front yard. They had recovered it from their neighbors roof, were it “landed”. I was so happy that I had found the plane again, and it wasn’t broken at all. Just some scratches – nothing serious. So I packed it into my trunk, said a thank-you and drove away with a big smile on my face. What a Sunday!

Yesterday I thought about how we use the freedom we get from building and flying experimental airplanes. Most designs have pushed the performance envelope in some way and have traded off flying characteristics of the plane – many times stall speed. But it occurred to me that not many people are actually pushing the design of the cockpit very much. Sure, we install non-TSO’ed flat panels and such, but most of the experimentals pretty much still look like work in progress from inside. I have yet to come across an airplane that looks and feels like the latest generation Lexus or BMW from inside. Why is it that we put so much effort into squeezing out the last bit of performance, weight, while neglecting creature comfort? I’ve been dreaming about parting out a state of the art luxury car and using all its refined interior parts in an airplane. How would that power seat feel? Or those eight vents? Or that wood accent (OK, the Beechcraft crowd knows that one). And how cool would that instrument cluster look with that integrated fit and finish? Sure it’s heavy and of course it will slow down the airplane and hamper climb performance. But flying such an airplane would be a so much more indulging experience.

in my job I work a lot with cross site teams together on big projects. In this setting it happens at times that you collaborate with some people at the East or West coast that you’ve never met in person. Over the weeks, months, and sometimes years, a mental image of that person emerges in your head from all the interactions that you’re having on a daily basis: Emails, phone conferences, presentations contribute to the mental image you’re building. Then eventually you get to know that person face to face and so far every single time I’ve gotten a big surprise, because the mental image you’ve build never matches the looks of the actual person. Only if you force yourself to not look at that person, the voice is familiar. In some strange way the person that you had in your head gets replaced with its real person. The first couple of days it still conflicts with the mental image you had before, until it slowly fades away. This is a very strange experience every time it happens.

a couple of weeks ago I got reminded why you’re not supposed to rely on the engine in a powered glider.  I was flying cross country, but wasn’t feeling well. After 150km I got low and needed the engine. Close to the chosen airfield I fired up the engine on base and climbed away. Since it was the middle of the afternoon, I soon found another strong thermal and climbed back to cloud base. The flight back home was no problem and I started my final glide from way below glide path, hoping to gain some 2000ft on the way (we had streeting). 60km later I was on glide path for McCready 0 and I decided to press on, leaving behind a 5kts thermal (2.5m/s). Sure enough I hit lots of sink thereafter and found myself 1000ft below glide path soon after. With enough fuel on board I wasn’t worried and I was ready to put it to use should the need arise. The terrain on the last 8 miles to the glider port is almost unlandable, so you always want to carry enough energy into the final glide. Since it appeared that wasn’t going to happen that day I decided to motor home from the last private landing strip. I lifted the engine, turned on the ignition and hit the starter: nothing. Check-list, engine full out, ignition on, throttle closed, choke, starter. Again silence. Now only 600ft AGL my heart started pumping. Gear down, airfield is to the left, stay in glide range. Voltage check: 11.2V. Wow, this should read at least 12.6V, 11.2 is awfully low. But there’s enough power to run the ignition and fuel pump, just not the starter. I decide to dive and try to windmill the propeller to a start and use this maneuver to make my base leg. When I push the nose over to gain airspeed my altitude drops to 250ft AGL – not very comfortable. Phubb, phubb, phubbbububbbb, and the engine fires! I pull up, control my airspeed carefully to not stall and at the same time to not overspeed the engine under full power. When everything is stable I turn left on final and fly along the runway under power to climb away. Another voltage check reveals that the alternator is not working. I now run fully on battery power. I decide to motor the last 8 miles to my home field, as I cannot be sure to have enough battery power left to retract the engine after shut down. In that case my glide ratio deteriorates to 16:1. After a couple of tense minutes I reach the field uneventfully and am still able to stow away the motor. Upon closer inspection I later find out that one of the copper cables from the alternator had disconnected from corrosion and therefore the alternator didn’t produce any current. That was easy to fix and now everything is back to normal. Nevertheless this incident served as a reminder to never completely rely on that metal thermal in the back. One day it might just not be there for you to bail you out…

Murphy is watching: just as we get ready to fly out to California over Labour Day week-end this year, things get a bit crazy. Both my cars have been acting up and I had to fix the Explorer last night to be able to drop the dogs off this morning. Checky-mark.

Last night we had to pack, but friends from CA flew into town and we wanted to meet and greet them, since we hadn’t seen them in a while. That pushed out our other activities that night and we only got to bed by 1am. 5hours of sleep should suffice for one night.

It was my night to watch over RoRo (we take turns) – usually not a big deal. Normally he sleeps through the night and wakes up around 6am, which is when I wanted to get up anyway. But the baby had different plans this time. He woke up at 3:30a and refused to go back to sleep until 4:50a. I tried every trick in the bag and nothing worked. That has never happened before. I went back to sleep and delayed my alarm to 6:40a, but getting up in the morning was torture nevertheless. With the leftovers of cold that I’ve been battling over the last three weeks I was in everything but good spirits this morning. But the dogs had to be dropped off and I had to go to work.

When I showed up at our friends place who’ll watch the dogs I rang the door bell of their neighbors – they weren’t too happy. On the way to work my check engine light on the Explorer came on again, but I made it to work – clunker, clunker!

And it’s only Friday morning. Let’s see what the rest of the week-end will bring. Go with the flow …

This post is written on a netbook computer – an Asus EeePC 900A. I got this machine this week from Woot! for the incredible amount of $179 + tax and shipping. It comes with a 4 GB SSD hard drive and is completely quiet. But the best part (and the main reason why I’ve bought it) is that  I’ve actually designed the floating point adder for the Intel Atom CPU in this machine. It makes me smile to know, that every time I open a menu, my little adder has to go to work.

Today, I participated in an engineering week event, that was sponsored by Intel. It’s intended to expose teenagers to engineering.  This gave me an excuse to visit a middle school and see it from inside. Having gotten all my education abroad, I actually have never been inside of a US school. I only “knew” it from TV. It’s quite different from our schools in Germany – lockers everywhere!

The class format allows the students to design a puff-mobile (a vehicle propelled by your breath) from a set of simple parts that are provided: sheet of paper, three straws, four ring sized cough drops (Life SaverTM), two paper clips and some tape.
The kids split up in teams of four to design and build their own vehicle. After 30min they compete against each other. They have to explain their design and then race it against the other team.
The ingenuity of the kids surprised me. Not one vehicle looked like the other. And the results of the race were even more unpredictable. We managed to get the crowd going and in the end the 25 students were standing around the race track table cheering each other on. We managed to talk about some engineering concepts as well and left the class after one and a half hours.
This was definitely fun and I will repeat this next year!

Despite my restrictive diet, I enjoy a juicy steak on rare occasions. Yesterday was such a day. We stayed at home and cooked. I made two juicy high quality beef fillet steaks and cooked mine rare, MrsM.’s medium. Along with garlic mashed potatoes and red cabbage and onion rings it made for a perfect dinner. Hmmmm – yummy!

Reading a recent article about premature termination of an aero-tow reminded me of a downwind landing I performed more than 15 years ago at Lachen-Speyerdorf, Germany. That day we had very strong SW winds that created a local wave. We departed in a ASK-21 on aero tow on runway 30 to release in the rotor. There were plenty of clouds from a cold front that had just passed and the grass runway was still soaking wet from the last showers. The wave window had nicely formed with a 5 mile wide window of blue sky in the lee of the mountains. On tow we climbed out slowly against the strong headwind in very turbulent cold air. The light was bright and the contrast from the cloud shadow just to the side of us made for a spectacular view. Andreas and I were flying together in the club’s ASK-21, trying to reach the rotor and then climbing into the wave. We released 5 miles away from our take-off destination at 2500ft AGL. The vario was dancing violently but we soon managed to circle in strong turbulent lift of 5 kts (2.5m/s). This produced a big smile on our faces, and we were already thinking about the best strategy how to jump into the wave from here. We didn’t even finish our thought before our 5kts lift turned into 8kts sink. I tried to stay calm and search for the lost rotor upwind. Accelerating the glider in sink is a daunting task. The needle of the altimeter moves at the same speed as the airspeed indicator increases. We were falling out of the sky. After one or two search S into the wind it was clear that we had lost the rotor and probably our chance to fly in wave for the day. We switched gear into “getting home” mode and pointed the nose towards the airport. With 45kts tailwind I wasn’t too concerned to reach the airfield. The terrain right below us was unladable with vineyards, but farmers fields would start half way home. The trouble was there was water everywhere. The sink was brutal. We were beaten down from the lee with 10 kts sink. The ASK-21 isn’t a particularly fast glider either. With a strong tailwind we weren’t supposed to fly super fast either. But the strong sink dictated fairly high speeds anyway. So we pressed on. Andreas was very quiet in the back. I told him that we could turn into the wind any time now and land on any of the wet fields below us, if the sink continued. I called on the radio for a straight in on runway 12 – well aware of the 25 kts tailwind on the ground. Our runway is 1000m long and I figured that would be enough if I touched down early enough. Going all the way for a pattern to 30 wasn’t an option any more. I kept my field landing option until the last mile and then committed to a straight in for 12. How fast are you supposed to fly your approach in this turbulent air? I opted for 130km/h because of the tree we had to overfly with the wind from behind. We made the tree, full flaps, made the runway and flew, flew, coasted coasted, floated, floated and floated, eating away runway at an alarming speed. We finally touched down shortly after the half mark of the runway, where I used full brakes. That’s when I learned about my biggest oversight. The runway was wet and friction for braking power from the main wheel wasn’t available. We skidded down the runway with 80km/h, 300m to go. Shortly after I lost all roll control from the ailerons because of the tail wind. The right wing dropped at around 40km/h ground speed and we were still skidding despite pumping the brake. Thanks to the wet ground the glider never ground looped and we luckily overran the end of the runway by a mere 50m. There weren’t any obstacles in the path. Then it was quiet. I was shaking. My heart was pumping. Our camarades came running towards us and a quick look at the glider confirmed that nothing had happened to the sailplane. I was very shaken and will never forget about the downwind landing wind speed limits and loss of traction on a wet grass runway.