Efficiency and Model Aviation - II

In February of 2015 I had written a blog post entitled “Efficiency and Model Aviation”; the article placed emphasis more on simpler rubber powered free flight although it did mention the super-efficient F1D indoor free flight competition models. As the comfortable outdoor flying season is winding down where I live I am thinking about some of what I learned about model airplane efficiency. Much of this is related the radio control glider flying I do but I am now thinking about more efficient outdoor free flight models also.

My Allegro Lite RC Sailplane Efficient but Not Compared to Larger Sailplanes

Recently I watched a NOVA program entitled “Making Stuff Faster”; it can be watched online at this link http://video.pbs.org/video/2365099550/ . Of particular interest to me in this program was the Oracle sailboat which is capable of top speeds over 50 mph and the Velox 3 bicycle that set a world record of 83.1 mph.  New technologies made possible by new lightweight materials made the high-speeds obtained possible.

Foam Super Scooter Not Real Efficient

Fiberglass Shadow More Efficient

Radio Control sailplanes I fly stay aloft because of lift from deflected air created by the wind blowing against a slope or from rising thermal air currents.  For the slope flying I have been moving away from gliders made mainly from foam to gliders that are more rigid built from fiberglass and other rigid materials. Flying from the same slope with the same conditions on a particular day the difference in performance is amazing.  At times the foam gliders will not stay airborne for more than 30 seconds while with the more efficient fiberglass gliders I can fly easily for several minutes. The reason for this goes back to my first article where Lift / Drag were discussed. 

Xplorer Sailplane Very Efficient

Circling in Thermal Lift

This summer I also flew in some thermal duration sailplane contests. Compared to other sailplane pilots my sailplanes did not perform very well. Much of this was piloting skill but still I was at a disadvantage flying smaller sailplanes in competition against sailplanes with twice the wingspan. There are aerodynamic factors of why these larger gliders are more efficient in using the available lift from thermal air currents than my smaller sailplanes.

Electric Starduster Climbs Steep 

Pearl E202 Construction

Electrical Components Texas Timers

Looking ahead for 2016 I plan to do more flying of larger, more efficient outdoor free flight models. A big factor in outdoor free flight competition is how high the model will climb before going into the glide. I am building the Pearl E202 E36 electric powered free flight but to test the electric components it will use, everything was installed in a larger glow powered airplane. The power system of brushless electric motor and a lithium battery that provides current at a very fast rate allow this plane to climb darn near vertical.  

Lidberg NJAPF P30 Model

Brought out from collecting dust in the basement recently is a rubber powered P30 competition class model. With old rubber strands for a motor, the climb rate was not too impressive on some trim flights. I have been given much advice on the strand make up of a rubber and how much to wind it. No doubt the airplane will give much longer flights in the future when flying more efficiently.  The previous summer I had experimented with a free flight discus launch glider. I went through phases of learning how to launch it without breaking, getting more consistent high launches, and then adjusting for a longer glide. Next year I plan to finish another glider as the first one flew away in a thermal air current.


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


Vendors Mentioned

Texas Timers – electrical components for E36 free flight 

PearlFreeFlight  - E36 free flight kits  

AA Lidberg Plan Service – NJAPF P30 rubber power free flight kit 


Xplorer RC Sailplane 


Related Blog Articles

Efficiency and Model Aviation

Slope Soaring a Heavy 2-Meter Glider on a Small Slope

My Small Slope Soaring Webpage

Allegro Lite Finished and Flying

Watching the Super RC Sailplanes on Saturday



Unwinding With Free Flight Discus Glider

Free Flight Glider Discus Update

Tip Launched Glider Slow to Come Down

Goodbye to My First Tip Launched Free Flight Glider

How Do Fish Get into Small Ponds

I have been fishing for largemouth bass in one particular pond fairly often and someone had asked me how did the fish get into the pond?  That is a question I have pondered also, sorry bad pun opportunity. Searching the Internet it seems like many people have asked that same question. Probably the most popular answer is fish eggs attach to the feet of water fowl and travel with them to be deposited in new bodies of water. Some people really questioned how often that actually happens but other people replied it only has to happen rarely and fish multiply quickly. Times of flooding are another opportunity for the fish to travel to new areas.

I thought I would do a little experiment on my own and check out a small man made pond that was created by Apache Mall in Rochester Minnesota. After purchasing some red worms at the Scheels sporting goods which is just across the highway from this pond, I threw out a worm on a small hook with a bobber. The bobber had barely touched the water and it started to go under. I pulled back and started reeling but there wasn’t much resistance, it was a tiny bluegill about 3 inches long. About this time circling vultures started to come closer, probably just to see what this crazy guy was doing by the small pond.

In the process of maybe 20 minutes I caught three more bluegills that were all the same tiny size. I also tried fishing in a small lake in Rochester where I caught only the more silver colored sunfish, these were somewhat larger. I have heard there are largemouth bass in the lake. In the pond I do not know, maybe without a predator fish the bluegills remain stunted in the pond.

More research no doubt could be done on these observations. 

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

Related 

Low Investment Bass Fishing

Fantastic Foam Flyer

It is amazing how sometimes with the right combinations of factors something that appears so simple can perform so well.  I received a kit for a simple all-balsa rubber powered model airplane known as the Blue Ridge Dart. I assembled it in less than an hour and was testing it outdoors even with snow on the ground. I was amazed at how stable it flew and the duration was good. My thoughts soon went to designing a similar model using foam plates instead of thin sheet balsa as the primary building material, the fuselage is still balsa. As the amount of flat material is limited in a foam plate, I built a 3-piece wing with flat center section instead of a 2-piece wing, the tail surfaces are slightly smaller too.

College for Kids Class

The prototype airplane was assembled using low temperature hot glue as this would not destroy the foam and is a quick method to build.  First flights were very promising; this plane really climbs on 1/8” wide rubber. It has a long fuselage which makes for easy winding by hand if there is no slack in the motor loop yet still gives a pretty long motor run. I wanted a very stable flying foam airplane for kid classes that I teach and previous design ideas didn’t seem stable enough in some cases.

Fantastic Foam Flyer

This past summer for the Engineering Through Models class which is part of College for Kids at WSU I introduced this plane to the kids. I had built the simple balsa fuselages and traced out the parts on foam plates, this way they only needed a scissors and low temp hot glue gun to build the airplanes. Construction went well and they flew the planes indoors because it was rather hot outside. The planes flew well and survived many hits to the walls and floor pretty well, I was impressed. On the last day of class I showed the students how one of these planes could fly outdoors when really wound up. It was a calm day and the plane flew very high over the campus but landed close to where it was launched, they were impressed.

Flying High over WSU Campus

3-Panel Wing

My longest flight outdoors ended up in me losing sight of the model after close to 3 minutes as it became a tiny spot hoisted aloft in a thermal air current. An online friend of mine that built one of these planes had a similar experience and lost his on the first flight after watching it for over two minutes.

Denny Dock and Grandsons built planes for camping trip

Paul L. Built a Gull Wing Version Too

Propeller from Sky Streak Worked Well

The article on my website has very detailed construction steps and the flying surface templates can be downloaded in PDF format. Propeller assemblies can be taken from other all-balsa planes such as the ones sold by the Guillow company.

Construction Article Link   - Fantastic Foam Flyer

FFF at 30 Second Film Festival

Blue Ridge Dart 

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

Videos

Glue Plane Quickly

Flying High Over WSU

30 Seconds Construction Video

Flight Phases Shows Over Minute Flight

Observing the Total Lunar Eclipse September 27, 2015

Last Sunday evening there were a bunch of factors that came together when I viewed the total lunar eclipse from the Mayo High School parking lot with the Rochester Astronomy Club. This was a rather special lunar eclipse in that the moon was unusually close to the earth causing it to appear both larger and brighter this combination only happens every 30 years. It was a clear and warm evening plus I was already in Rochester Minnesota so when I heard the astronomy club was hosting a public viewing I couldn’t pass up the chance to look through some really nice telescopes operated by knowledgeable people.

Pictures from Cosmos TV Event

I had first learned of the Rochester Astronomy Club when I had shared a table with Everything Hobby of Rochester with some of my project material from my website at an event for the Cosmos: A Spacetime Odyssey TV program hosted by Fox 47 TV. That evening it was not good for outdoor viewing but the astronomy club had an impressive display of telescopes and other related materials.

The next factor in my interest in astronomy was when I received a DVD from Astronomy Magazine, after I watched the DVD it seemed really interesting and I purchased a bunch of their DVD’s after this. More recently I had purchased a small telescope and have been learning how to use it.

For the lunar eclipse viewing there was a really a good number of people of all ages present and members of the Rochester Astronomy Club were very helpful in helping the public view the eclipse through their telescopes. Several people including myself were trying to take pictures with a smartphone focused through a telescope lens, this was not easy but one of the members took a really impressive picture for me using my phone.


I had written previously an article about the “Blood Moon” and why the moon had the red color during the eclipse.

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

Related Links

Rochester Astronomy Club

Blood Moon Basics

Everything Hobby

Fox 47 TV

Astronomy Magazine

Taking the RC Dart Glider to the Backside

Sometimes taking a risk is a good thing, other times maybe not but this post is not about the stock market. I had put together a RC sailplane with some modifications with the intent to slope soar it and to use it for dynamic soaring. I had added ailerons and stiffened an already strong wing with carbon fiber and Monocote covering. After the first session of flying it on the slope there was a minor crack in the fuselage so I added additional fiberglass, a hard crash with this glider probably would not be good.

My last flying session started with flying the foam Super Scooter which can take some real hard knocks without damage. I try to DS this glider and find it difficult to get more than about three laps. My feeling is this is like using training wheels; chances are I will not wreck the glider with a mistake. To make it work at all the flying has to be really smooth and close to the backside of the hill. Foam gliders will DS better on larger hills but a small hill was what I have to work with.

After struggling to stay up on the front side of the hill and a few of the 3 lap backside circuits I decided to fly the Dart again. What a difference, it was flying high over the front side; I tried a loop; that was easy. Finally I got up my nerve and made a pass around the backside; that was really easy. I tried it again but with more circuits and letting it go farther out over the front side.  It was like flying a controline model doing the nice round circuits. It sure was easier than the flying the foam glider.

I was flying with a friend who agreed to get video of my flying but now the conditions were not as good. Even on the front side I was struggling to keep the Dart up, it seemed windy enough but the lift just wasn’t there.  On the early DS flight I was able to dive from a good altitude with really good speed and that made it easy. Now I came into the back slower and the speed remained slower. It was getting time to leave and the wind appeared to be really gusty at times. 

Foam Super Scooter

Looking back I was glad I took the risk of trying DS with the fragile glider.  One cannot ride their bike with training wheels forever and I need to fly gliders that will work better with the hill I have available.  If I could go out there again and fly 50 DS circuits consecutively I have to believe my skill would improve.

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

Related 

Multiplex Dart DS video   new

Small Slope Webpage

Multiplex Dart Hits the Slope

Dynamic Soaring Goal Raising the Bar

Placing Last in RC Soaring Not so Bad

This past Saturday I entered a thermal duration contest knowing full well that my chances of placing well in the contest were very slim. What was more important to me was enjoying the wonderful weather for soaring with other soaring enthusiasts, learning, and flying a glider that had belonged to a member of the soaring club that passed away. The glider which flies well is at a big disadvantage being smaller with only a 2 meter span when the other sailplanes are at least 3 meters. I was not finding very strong lift and what little wind there was seemed to really hold my glider back when landing.

What I found so interesting was watching the other sailplanes flying in thermal lift, noting where they were flying relating to the field and features on the field such as trees and cornfields. One of the members mentioned that he does a great deal of practice flying and always has a plan before he launches as to where to fly.  I started thinking about my sport flying in that I might launch a dozen times and then hit thermal lift strong enough that I can fly it to a good altitude for a 6 minute flight. Contrast this to the contest where I only had 6 launches, and it is apparent that my odds for getting a good flight are not real good.

I sometimes think of some of the earliest radio control competition I was part of, pylon racing. A few guys from the club I was in were going to try the .15 size quarter midget class, starting with sport type .15 engines. Racing against members of a more experienced club sure was a shock; they passed us like we were crawling around the course. Better engines and airplanes were the next step for us and we started to do much better.  Then there was the ½ A class using the Cox TeeDee .049 engines, from what I had learned in .15 class I did really well in ½ A, in fact I never lost a race. That was because other people in this class were really beginners doing well just to fly without crashing. After a while I found it boring winning all the time and went back to racing the .15 size.

On Sunday I decided I would fly my glider in rather windy conditions as one of the expert pilots had said how he often flew in the wind, this year we have been lucky contest days have had rather light wind but often that is not the case.  My two meter glider was getting bounced around in the wind at times but I could tell the air was buoyant.  After several launches I noticed the hi-start was really stretching out, I knew I was in good lift. This time I circled my glider tighter and that is what it took, it was going up at a pretty good rate. The glider was slowly going downwind, a turkey vulture joined it in flight but I knew I better try penetrating the wind back or where it might land could be bad. 

I pushed the nose down and kept coming back as straight as possible. My sailplane was flying over a bunch steel scrap and I was afraid it might land there and really do some damage to the glider. There was an animal clinic on the edge of the field and I thought I could land in the front lawn. Just as my glider started flying over the lawn, a gust whipped it into a small tree. The glider spun around and flipped inverted and crashed. Luckily the only damage was breaking off the vertical fin, an easy fix. It was a pretty good flight actually and a learning experience on pushing the limit a little too far.


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

Sky Bunny Postal Labor Day Weekend

I was finally ready for a model airplane postal contest this past weekend, having built a Peck Sky Bunny from an older kit and not the new laser-cut kit. It was good to have a three day weekend to try to get in some flights, I wanted to try to fly during the better weather but didn't want to wait too long and have the contest ended. Postal contests are where flyers time their own flights and send the results to the contest sponsor, when the idea first started correspondence was by postal mail, now these contests are held over the Internet. Gary Hinze who is a major contributor to the Endlesslift blog did an outstanding job getting the word out on this contest.

The Sky Bunny is a rubber powered free flight model airplane that is not a pure beginners model but might be considered a good second model to build. It can be flown indoors but is normally considered to be an outdoor model, it does not have a dethermalizer as part of the design but it can easily fly out of sight in thermal lift.

I got up early Saturday morning hoping to fly before the wind became too strong. The field I was flying from is small, on my first launch my Sky Bunny circled so close to a row of trees, somehow my plane missed the trees. After changing the launch spot I had a 56 second flight, not wanting to risk trying for a longer flight from the small field I called that enough. Sunday was windy and rainy so no flights were tried.

Monday morning it was overcast but the wind was low and had switched to the north. The first launch of the Sky Bunny ended quickly as the plane had too much right turn and went into a spiral into the ground. I adjusted the rudder tab but now there was almost no turn, I chased it across the somewhat larger field I was flying from. The next flight the turn was about perfect but the rubber motor seemed tired so I switched to a new rubber motor.

Another launch and the Sky Bunny was climbing like crazy from the start, even after the initial steep climb during the power burst the plane just kept climbing as it circled, it had to be in thermal lift. This was just what I wanted but I was wondering if would ever see the airplane again. It did start to come slowly time but this time my stop watch showed 109 seconds, wow was that cool. I considered stopping with that flight but decided to try again since I was getting so close to two minutes. One more try and the plane was again circling so high above, maybe this would be the last flight but no, it did come slowly down but this time was 115 seconds.

After risking the Sky Bunny several times over the weekend I decided I would accept my last time and go home with my Sky Bunny. As good as my flights were they were no where near what it would take to win the contest. I read that  Bill Vanderbeek had a flight of 490 seconds and then lost sight of his Sky Bunny. It certainly is possible I had lost one of my rubber powered foam airplanes after watching it for over 3 minutes at this field before I could not see it any longer.

Second Place

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

Related 

Sky Bunny Postal Endlesslift

Peck Website

Fantastic Foam Flyer   - My design rubber model that flew out of site.