Tuesday, October 28, 2014

Getting Lost at a Scout Camp

On a wonderful recent fall Saturday I was invited to observe model rocket launching and pumpkin chunkin. The scouts had two different types of rockets, very tiny ones with tumble recovery and a slightly bigger rocket with a streamer that slowed it down, making it a little easier to see also. They were also setting up for a “pumpkin chunkin” competition in the afternoon.  I did get to see a couple of pumpkins get launched and it was amazing the distance the pumpkin was hurled through the air.

While at the camp I decided to take a hike on a trail that went into a wooded area, I had heard there was a reservoir lake somewhere in the area that radio control gliders had been flown from. I walked the winding trail that had been cleared noticing the orange plastic ribbons that were found along the path. Any moment I expected to come to the end of the trail but at some point it appeared to follow a half circle and I thought sure I was headed back to where I had started. When I thought I was getting closer I moved off the trail so people riding mountain bikes could get through. At this point it appeared like there was an opening in the woods ahead.

As I left the wooded area there was a big valley with an earth dam at the other side. I crossed a small stream on wood planks spanning the water. Someone else was walking a road up to the top of the dam; I followed them and looked out over the beautiful small lake.  Next I headed down the path I came up and followed a dirt road that two guys were coming my way on with fishing poles. They asked me how fishing was but I said I had no idea and this was the first time I had been here. As the trail went around some trees there was the parking lot for the reservoir with plenty of signs but no trail maps.

Leaving the parking lot was a crushed rock road, but which way to go, right or left? If I would have been a good scout I probably would have used an old fashion compass but I had Google on my smartphone. Turns out it wasn’t so smart but it gave me a warning it was a beta version. It had me going up the hill to the left but was showing the address I was looking for several miles away. On top of the hill I didn’t spot the camp headquarters so I went down the hill. Looked at Google again and it had me going the other direction up another hill. Spotted an exit off the road to what looked like many vehicles, I thought that must be where I came from. When I got to the driveway I could see that it was a farm place not the scout camp. So I went down the hill again and up again. Finally I got up nerve to flag someone down and asked which way to the scout camp, they pointed the other direction and quickly took off.

It was a wonderful day for a walk but this was getting to be a bit much. At the bottom of the hill in the parking lot I spotted a guy getting a bike ready to ride. I asked him if there was a shortcut to the boy scout camp, he didn’t know and his smartphone wasn’t coming up with anything useful either. I continued up the hill past the farm place and spotted the road on top of the hill that goes by the boy scout camp. I certainly didn’t want to walk that far but then I spotted the camp across a field, so walked across tall grass but it was shorter than following the road.

View Across the Field

Almost Back

Pumpkin Chunkin Testing When I Got Back

According to my pedometer I had put on 6 ½ miles that day so I would guess 6 of the miles were my trail adventure. It was now lunch time; I stayed to see a couple of pumpkins flung from a giant wooden contraption and then headed back to the city.

Happy Trails

Bill Kuhl

Monday, October 20, 2014

Fall Flying Fun

Last weekend was great for a variety of flying activities; Saturday was our monthly glider get together with no contest but still a good turnout for thermal duration flying.  The wind was light and thermals were available if you could find them and stay in them.  One of the flyers also has an interest in solid fuel model rockets and did several launches, I brought some water rockets to demonstrate also.

The glider I was flying was with a Hyper – DL  a discus launch glider.  I was finding some lift but seemed to  be able to climb only so high before losing the thermals.  Other people were having difficulties staying up for extended duration too.

I brought out my newly repaired Cessna 150 electric RC for another test flight after ripping the wings off in flight last time out. The cabin area was reinforced and carbon rods were put into the wing halves, problem was I had almost no dihedral. I found out with only rudder control for steering, controlling the plane was impossible. Broke another wing off in a crash but now I am fixing with the needed dihedral.

After This I am Fixing the Cessna Right

My friend George took a break from sailplane flying to launch his rocket, wow that was cool.  I launched some simple bounce water rockets and then tried my new water rocket with side deploy parachute. This idea had worked well on another rocket but I don’t think I wound the rubber band that wraps around the spring mechanism enough. The rocket went up real straight but came down that way also, it appeared undamaged because of all the foam in the nose area. It might have loosened the fins as on the next launch two of the fins ripped off before the rocket could get very high.

George Launching 

Water Rocket Ready for Launch

After this I chatted some with Dean who is an excellent sailplane pilot, he had landed after flying his Supra for 47 minutes and came down to charge the batteries.  Dean said that fall thermals can be strong but are normally small in diameter. I started launching my Hyper DL again and hit some lift that I could have taken out of sight. Having flown so much previous I too was worried about my battery and landed.

Dean with Supra and DLG 

Sunday the wind came up and I flew my Super Scooter EPP slope plane from a bigger hill for the area.  When the wind really started blowing the Scooter really came alive. On one pass close to myself I noticed this big bird, and then I saw it again, it was a hawk coming after my glider. After about three passes and no contact it flew away.  I got braver with the flying and was easily doing loops and rolls further out from the hill.

Super Scooter

 Bill Kuhl

Monday, October 13, 2014

Guillows Cessna 150 Flies

After building as many model airplanes as I have, one would think I would be pretty confident that each new plane will fly but there seems to be a little shred of doubt. The Guillow’s DHC-2 Beaver I converted to radio control is flying well after some initial glitches and I learned much from that project. For my next stick and tissue rubber model conversion I selected the Guillow’s Cessna 150 partly because the wing was thicker with a wider chord, this should provide more lift.

Guillow's Cessna 150
Cessna in Flight

 For this conversion I decided to use better equipment than the equipment that came out of a wrecked Parkzone Champ used in the Beaver. To start with I selected a brushless electric motor for more thrust and a 2 cell lipo battery. For servos the Spektrum A2010 servos were used that have a plastic case around the electronics. All of these components and the Cessna kit were found at my local hobby shop Everything Hobby.

Electric and Electronics
Balsa Structure

 Guillow’s has been selling the Cessna 150 kit forever but this was a new laser-cut version. Normally the wood in Guillow’s kits is rather heavy but all the wood in this kits was rather light, even the stringers. More than once I broke some of the structure while building, in most cases I replaced with heavier wood. Mounting the electric motor and the servos was done in manner more like larger airplanes but I needed to provide access to the battery and power connectors. My decision was to build a framework around the battery from toothpicks and create a side hatch on one side below the windows.

 Another departure from my previous conversion was to use a plastic iron-on film known as “Microlite” instead of tissue covering. For the most part the covering works well but it can be a bugger to separate the plastic backing from the covering. It also tends to stick to itself and can be impossible to separate if that happens. Shrinking to the structure works well but the fuselage structure was not rigid enough and it looks like a starved horse, at least someone called it that.

 After putting so much time into this plane I was getting anxious to fly it, even without a side hatch or wheels, struts, or trim. Saturday was a relatively calm day so I decided to give it a test flight. On launching it was immediately apparent motor/battery combination provided plenty of power, flying at half throttle or less should be a good cruise speed. The airplane was climbing too much and seemed a little wobbly in the air so I landed. Put in more down trim and flew again keeping the speed down because I did have concerns with the wing attachment. 

 Then coming by fairly low I saw one wing half rip off the airplane and amazingly I landed it pretty well as the other wing half was ripping off also. There was no other damage. I could see that the cabin structure and wing attachment would need additional reinforcement and now I would not have to cut off the wing halves. Wings are now attached again and the structure has been reinforced including some carbon rods. I will install the hatch and the struts before attempting another flight. This plane definitely has potential.

 Bill Kuhl

Related Articles

Guillow's DHC-2 Beaver Flies and What I have Learned

DHC-2 Beaver Conversion

Cessna Flies and Cessna Dies - I am afraid not a happy ending to this story.

Monday, October 6, 2014

Making My Dynamic Soaring Goal

In model aviation there are a few types of flying that seem like magic to me; one is the super lightweight rubber powered free flight airplanes that fly for over 30 minutes at a walking pace, then there are the walkalong gliders that fly in deflected air just in front of a board pushed by someone at a walking pace, and then there is the dynamic soaring of radio control gliders. 

 Dynamic Soaring or DS is flying a glider in a circular path behind a slope with a sharp ridge and using the boundary layer of air between the windy and still air to gain energy as the glider passes quickly through on each circle. The speed record for this type of soaring was 498 mph in 2012, maybe it has been surpassed.  Update 505 mph in 2014

My JW Glider Flown by Pat Bowman in DS Circuit

On several slope soaring trips I was able to observe dynamic soaring and one day was able to successfully fly some DS circuits with my JW glider. In the video embedded in this article you see Pat Bowman who sold the JW glider through his company flying my JW through some DS circuits. Pat made it look easy but I found it stressful but fun. For whatever reasons I was away from slope soaring of any kind for several years until a couple years ago I was slope soaring from smaller hills closer to where I lived.

Some of these small hills had slopes on both sides and I tried making some DS circuits without any luck. After a sharp turn at the bottom of the circuit, the glider just lost all the energy to keep coming back up. One of these slopes had a flat road on top which I found out reduces the efficiency for DS. I kept practicing trying to make circuits on the back side of the hill, just to get more comfortable with diving the glider over the backside of the hill. I even tried electric gliders and adding power to make the circuit upwards along the backside.

The Ridge I Used for DS

There was another hill that had a sharper ridge on the top and I thought with a more efficient glider it should be possible to make some DS laps. Finally a week ago everything came together, the wind was coming into the hill fairly straight and I had a DLG glider that was much more efficient than my foamie gliders. First I started on a lower portion of the ridge making circuits around the backside of the hill and out into the wind, just to get more comfortable with the process.

The Backside of the Slope

Soon I moved to the highest part of the ridge and went for making more than a single DS circuit. After getting the glider fairly high on the windy side, I dived it across the top of the ridge down along the backside. This time I did not pull it back as quick as normal but did more of a round circle and the glider came back up the hill shooting upwards with speed. I pulled on the elevator and sent it diving down the backside again; I was really doing the DS circuits now.  After a few circuits I let the glider fly over to the wind side maybe I could have kept going but I needed to calm my nerves.

Flying Super Scooter on Front Side Earlier

In the current issue of Model Aviation magazine is an article in the Sky's the Limit column by Jennifer Lilley, “The Magic of Body English for Flight Perfection”.  Maybe that was why I was successful with the dynamic soaring this time because I was really into the body English on each lap of DS.  I was able to repeat doing several laps a couple of more times and then quit because it was starting to get dark and my glider was still unbroken.  What a thrill!

Dynamic Soaring Weekend   about my next chance to try DS

Bill Kuhl

2003 Video of DS Flying

Dynamic Soaring technique by Glidingvideo