Unwinding With a Free Flight Discus Launch Glider

For me the model aviation hobby stays interesting if I take on new types of projects which present new challenges.  This past winter I built a discus launch free flight glider known as the Maxima 30 designed by Len Surtees. I have flown radio controlled DLG gliders before but I found out that it is more of a challenge when you have no control of the glider when it leaves your fingers.  Launching a glider by spinning around while holding one wing tip can give tremendous launch height, but can also result in plane-breaking crashes as the glider hits the ground at high speed. 

Construction of the wing uses solid sections of balsa that require shaping but there are large sections of the wing which use balsa ribs. Carbon fiber strips run the length of the wing both top and bottom and the dihedral breaks are reinforced with fiberglass. Covering was with a material known as Polyspan which worked well and appears to be very tough.

As of yet I had not installed a dethermalizer (DT) in a model plane which presented a new challenge that I have much to learn about. The Smoothie MK III was included with the kit but I have had trouble gluing the arm to the rotary damper part of the timer. I ended up building by own arm out of tubing. In testing using a rubber band pulling on the rotary timer I could not get it to run for more than 30 seconds. If less tension was used it would stop. Switching to tiny springs I had purchased for this purpose worked much better and would give a much longer time before the DT would pop up.

DT Set

DT Popped Up

Learning to launch the Maxima has been more difficult than I expected, even after watching a DVD I purchased from the National Free Flight Society about DLG and Catapult gliders. The crashes normally are because you let go of the glider wrong and it curves the opposite direction it should and crashes shortly after launch or it stalls and does not recover before hitting the ground. Luckily the ground has been fairly soft lately because of all the rain. Still I have broken the glider the glider several times either at the balsa and carbon boom pivot point joint or in the nose where it is cut out for the DT. One time the DT broke free from the nose and was lost in the grass, will have to install a new one.

DT Broke Free and Lost

The last time flying I did not have to make any repairs hopefully my launch technique is improving. Transition at the top of the launch could be better; either it goes downward too fast or into a series of stalls.  There is an adjustment screw under them boom that can be tweaked to adjust the glide. Any type of model free flight glider is more difficult to launch and adjust than one would think because it flies in two entirely different speed modes, high speed for launch and then a slow glide. 

Dive Too Steep

Soaring High

Hopefully I will have a future updated report on this where I can brag of many long flights without crashing.

5/12/2014 Update

Many times tips from someone that has had success can make all the difference. I found this thread on Hip Pocket website that was very helpful "TLG Beginner's Launch Guidance". The one thing I notice was the glider should be launched with very little angle upwards and the glider climbs upwards naturally. I was launching at a rather steep angle. With this knowledge I tried flying again but the recovery at the top of the launch was still poor.

Another idea I had was to give the glider more right turn to help it recover. I increased the  rudder shim with some masking tape wadded up.  This really helped and with a little adjustment of the pitch trim the glide recovery was much better. Too good in fact for the small field in the breeze, it drifted diagonally across the entire field and landed in the road. 

This time I called it enough before I lost the glider. That evening I installed another balsa rudder shim and replaced the DT.  Think I am making some real progress now.

5/12/2014 Update

New post on my progress.

Bill Kuhl

http://www.ideas-inspire.com

2 Years 20,000 Miles on Prius Report

The 2011 Toyota Prius I purchased new in 2012 now is just over two years old and has very close to 20,000 miles on it. So far I still think it was a very good decision to purchase a hybrid car. As of yet there have been no problems with this car and the expected fuel mileage has been good. Average for summer driving is slightly above 50 mpg and during winter it dips into low 40 mpg range. It has handled fine for me when driving on slippery roads.

There still seems to be much confusion by most people on how a hybrid car functions. First of all unless you have a plugin hybrid, you do not charge the car from an external electrical source. The batteries are charged by the kinetic energy of the car when coasting or braking or by the gasoline engine. It is rather complicated how this all works but so far it has worked perfectly for me. Some of the time the engine is completely off such as when coasting or while the car is stopped.

This Might be Typical at 70 mph Highway

For the Toyota hybrid system the car can be powered entirely by the electric motor at lower speeds, powered entirely by the internal combustion engine, or a combination of electric and gas, this is controlled by the computer system in the car. Other hybrid systems may work slightly different. Your driving style and route can have much to do with the gas mileage results. The car begins moving first by electric to overcome the inertia, remember Newton's First Law of Motion?

Under Some Conditions Mileage is Really High

The internal engine in the Prius is an efficient design which helps greatly with the gas mileage. There are no belts on the engine for water pump, power steering, etc. The intake cycle of the engine is longer making for an engine than is more thermally efficient, that is more energy is converted from heat to useful mechanical energy. The claim is that this engine is 38% thermally efficient compared to around 20% average for typical gas engine. Without an electric assist for this type of engine the performance would be slow which is why it works well with the hybrid concept.

Other aspects of the car that contribute to efficiency are the transmission which constantly varies for the load. Tires that are designed for higher-mileage with pressure monitoring valve stems.  The design of the body is more aerodynamic than most cars also.

I look forward to when full electrical cars are practical for most people.
  

http://www.ideas-inspire.com
Bill Kuhl

Zip Wing Electric Free Flight Plane Available Where Toys are Sold

Passing through the toy isle at a department store I decided to see if there any actual flying model airplanes any longer. Not much of a selection but they did have the Air Hogs Zip Wing electric free flight model. I remember people discussing this on a free flight forum.  The performance is not wonderful but it is about perfect for a school yard or park. Like most toy store model airplanes it is not real stable out of the box.  The electric motor is powered by two AAA dry cell batteries which doesn’t give a rocket-like climb but it is adequate.

What I like about this plane is that it makes it so easy to get repeated flights without having to charge, pump, or wind up the plane before flying again.  The airplane has a built-in timer that cuts the power after about 10 seconds, the propeller folds back for the glide.  Not a real good glide however but for school yard flying that is probably a good thing.

Wing Needs More Dihedral

Like any free flight airplane, some adjustments might be needed to get the airplane to fly correctly. On the first launch of my Zip wing it nosed to the ground, it needed some up trim from the elevator surface. The airplane does not have enough dihedral, the instructional video on the Air Hogs website shows how to bend the wing to create some dihedral which is what I tried to do. I want to try find a better solution, the plane tends to fly one direction and then another.

I ran across a video someone posted on Youtube where they could not get the plane to fly, it always turned to the left and crashed.  This is the challenge and the fun of free flight airplanes, you MUST learn how to do the adjustments to correct the problem. Do not keep launching the airplane when the flight path is wrong. When I got my plane adjusted I was able to give it a fairly hard throw and it gained more altitude. What I did do wrong was not use a decal to hold the vertical fin in place and I lost it; a new fin was created from some foam I had.


Watch for more ideas on how to improve this plane as I try more modifications.

5/16/2014 Update

I added extra dihedral by bending the wing tips up and taping with clear tape. This might be more dihedral than needed for stability but I thought if the tape was removed maybe some of the bend would remain. The airplane did seem more stable in flight but I think maybe the wing was not lifting as well. My next idea is to add foam material to the trailing edge of the wing to increase wing area.

Description on Air Hogs Website

Bill Kuhl

http://www.ideas-inspire.com

Video of Airplane That Needs Adjustment

Related Article

Trying to Add More Zip to Zip Wing

Join My Facebook Group for Simple Foam Free Flight Airplanes - click link

Nickel Metal Hydride Battery Story

This is another story about how trying to be cheap cost more in the long run.  Several years ago I purchased this heavy fiberglass, foam, and obeche wood 2-meter glider. It seemed so heavy I did not get very excited about installing radio equipment until last year. Fall of last year I finally made some flights with it and was amazed how well it flew, especially in windier weather.

Shadow 2 Meter Glider

For this year I upgraded to a Spektrum DX9 transmitter from the DX6xi, learning to re-program the glider was a challenge but I figured out most aspects.  Luckily I did tests glides instead of trying a hi-start launch from the start. The radio seemed to be shaky and the elevator control was not that responsive. I took the plane home and installed a longer arm on the elevator servo, feeling confident the next time test glides would be better.

Cells I Soldered in Front With Date Battery Put in Service

Next outing control was not any better and the radio took a long time to connect up, I should have recognized that as a bad sign.  I had charged the battery again before flying and the battery was only a little over a year old. On the last glide I threw the plane a little harder, it went up and it went down hitting the ground rather hard. One wing suffered damage that I fixed to be strong again but it is not very pretty. I also checked the battery condition and was shocked to find it was really low.

Sanyo Eneloop Battery

If the battery was charged, putting it on the expanded voltmeter would drag the needle to the left in a couple of minutes. I decided it was time to do some research, my inquiry on the Facebook Sailplane and Soaring group brought several suggestions as did some emails to someone that had just mentioned they had battery failures on batteries less than a year old.  This person like me had soldered the cells together instead of buying a pack that comes put together. Further research pointed to the possibility of soldered cells having a shortened life span because of damage from the heat.

I ordered 2 Sanyo Eneloop nickel metal hydride battery packs because I am going to replace another pack I soldered even though it appears to be working good for now. Battery monitoring will be done more frequently as well.  With the new battery in place the radio seems more solid, the servos are faster and do not make noises when not moving. 

Checking Voltage

Lesson learned; it could have turned out much worse if I had crashed from a high altitude, no doubt the glider would have been totaled. Looking back to last season the radio equipment did not work as fast or as smooth like it does now but I am not real experienced in the 2.4 systems yet.

Bill Kuhl
http://ideas-inspire.com

Comparing Two 2-Meter  Gliders

Basic Aerodynamics With a Lesson

Spring Window of Opportunity for Model Airplane Flying

April in Minnesota is normally better for flying kites than for flying lightweight model airplanes powered by a strip of rubber because of the windy conditions. After a rather harsh winter I wanted to try one of my Guillow's Cloud Buster airplanes with the new 3/16" rubber strip I had purchased from Volare Products. Yesterday the wind was low after it stopped raining and I had taken time off from work to see a static display of model aircraft. I managed to get in a few flights in rather low wind conditions after I had made some corrections after flying the day before.

On this particular Cloud Buster I had used a propeller assembly that is designed to slip over the balsa motor stick and it appeared the friction fit had worked loose, this was fixed. The airplane would not fly a consistent circle path and I theorized the side thrust was changing because of the loose propeller mount. I also noticed a slight warp in the wing which I straightened out by wetting the tissue slightly and using a heat gun normally used for covering with plastic film covering.

With the new changes the airplane was flying completely straight which is not what you want unless you have a really long flying field. I experimented with some clay on the right wingtip until I had the circle about the right size. Happy with this I went to the static display which turned out to be cancelled. This gave me time to try flying again with a rudder trim tab in place of the clay which should be a lighter solution.

By this time my window of opportunity for good flying conditions has closed and it was much too windy to fly. That did not stop me from trying, to start with I had too large of rudder trim tab and the airplane did a spiral dive from launch. I removed some of the balsa tab and got one flight where it did fly a reasonable circular flight. By now it was really getting windy, the airplane would just point straight into the wind and hover or it would turn and go shooting downwind.

The last flight it went downwind towards a small pond, I watched carefully to get a good line of sight as the plane went down over the bank of the small pond. This a a brushy area and I had lost a glider there last year because I did not watch closely enough where the airplane had landed.  It did not take too much looking this time and I spotted the airplane just a couple of feet from the water's edge.


 I am slowly learning when not to push my luck and stop flying before I lose a model. It is also apparent further trim flights should be done under calmer conditions.

The first Cloud Buster I had built I reviewed on the Endless Lift blog, a second was built to try to build it lighter. I had drilled holes in the wing ribs but the weight savings was really pretty small, also a larger diameter propeller was used. Another day I plan to compare the flight of the two airplanes.

Bill Kuhl
http://www.ideas-inspire.com

Why I Still Fly Wind Up Airplanes

4-22-2014 Update

Having not really learned my lesson  I flew the Cloud Buster in wind, it landed by water at the bottom of a  steep bank. I managed to climb down to get it without falling in, I did leave my cellphone on top in case I did slide in. The dirt that started falling down the bank which broke the stab off.

With that much luck I decided to fly the other plane but I moved farther upwind. 

The wind was started to slow but the sun was going down also.

Blood Moon Basics

I set an alarm to view the astronomical event known as the "Blood Moon" or "Hunter's Moon" because several weeks ago the topic had come up with a group of guys I have coffee with. The person that started the discussion talked mainly about the connection between the occurrence of this lunar event and events in history.

Picture Taken Without Tripod

Wayne Diercks a relative who is in the group will often further research topics from the gab sessions using the Internet. The next week he brought in the story of how Christopher Columbus used his knowledge of an upcoming Blood Moon to scare the native people where he and his men were to give them food.

Cellphone Picture

The religious connections to the Blood Moon relate this phenomenon to the end times or the return of Jesus. For people of the Jewish faith this cycle of four Blood Moon's known as a " tetrad" coincides with  religiously significant dates.

What Causes the Red Color?

 The sunset red glow that circles the Earth as it blocks the light from the sun is cast upon the moon when the paths of the Earth and Moon are lined up. This would be a monthly event except the the Moon's orbit is inclined about 5 degrees to the Earth's orbit. From 1600 to 1900 the tetrad of eclipses did not happen at all. In the 21st century this is a more common event with nine sets of tetrads.  The next three will happen on:

October 8, 2014
April 4, 2015
September 28, 2015

Sorry for low quality pictures.

Bill Kuhl
Check out my New Website http://www.ideas-inspire.com

The Math of the Viral Sharing

After the large number of views to my new website article Simple Aerodynamics With a Lesson in one day, I thought I would examine the Likes and the shares to better understand how the views had spread. When the Academy of Model Aeronautics had posted a share to their Facebook page it started a large base to spread from. With 21,234 Likes to there page, 40 shares to my article were made with 115 Likes.

                              


The article also was posted to a Facebook group that I am a member of RC Soaring and Sailplane Society and had  19 Likes.  This is just one group I know it was posted to, there could be more. There were some nice comments as well.

My knowledge of social media marketing is rather limited, there are many people that do this as a career. I do see the possibilities.

Previous Article on the Article Sharing

Bill Kuhl
http://www.ideas-inspire.com