11-Dec-18 - 04:08 PM

Thermal Circle Text - Thermal Circle 21

Written by Hayden Daley - 13 October, 2009.
Welcome to this edition of the Soaring Circle. Firstly, I would like to apologize to the Silent Flight Network, its owners Henryk Kobylanski and Neil Spencer. I also wish to take this opportunity to apologize to the members of Scale Soaring Australia and also the Model Flight company. In the previous Soaring Circle column, I have wrongly stated in one of my captions that the sponsored tug was donated to members of the Scale Soaring Association by Model Flight. This caption is in fact not true, this particular model has nothing to do with the Scale Soaring Australia and it was constructed by members of the Silent Flight Network and is partly sponsored by Model Flight. This error was accidental and will not occur again. I would also like to state that two photos were published in the previous edition courtesy of the Silent Flight Network, and I would like to thank the network for their assistance in regards to the photos in the previous column. I did not mean any harm to, or to incriminate the Silent Flight Network, the Scale Soaring Association or Model Flight in the previous column. Through my error in the previous column, Scale Soaring Australia is not within its rights to expect use of, or control of this aircraft, the Silent Flight Network own this tow-plane and it is their prerogative to do with it as they wish. In this edition I have two aircraft to review from the Lanyu model aircraft company that is based in China. Model Flight are the distributors of these aircraft and have supplied the models for review. The first aircraft is the Lanyu 3B, a composite fully molded slope soarer. The second is a very large traditionally constructed 5.3 meter Minimoa.

I hope that this is just the beginning of affordable molded and Scale models in Australia. Personally I believe construction that was used in the S2G style of scale models could lead to affordable 1/3 scale or bigger models under $1400.00. in Australia. The Chinese model construction company’s have proven that they have the technology to construct both scale models and to construct good quality molded models. The models I have been provided with for these two review’s have proven this as being fact. Aerotowing is becoming more popular in Australia and when aerotowing, larger model's mean higher tows due to better visibility and it leads to longer flight’s. Personally, I prefer modern scale models of modern aircraft but can understand why people are attracted to vintage sailplanes. This is only the beginning of large aerotow models in Australia, as people become more interested in the relaxing flying that occurs at these events. In the United States aerotowing is getting a lot more popular. The U.S market generally dictates the trends and so on in that occur in Australia and as the requirement for large affordable models in the United States occurs, this will lead the way to these models making their way to Australia..

With the new giant scale model laws that have recently been passed by the MAAA this is an exciting time for scale soaring. These laws will allow construction of massive aerotow models due to the weight limit being doubled and paves the way for many ½ and 1/3 scale models to be constructed.

The Lanyu 3B

Introduction

The Lanyu 3b is new molded slope soarer that has just landed in Australia. It utilizes the MH32 wing section and its wingspan is just a fraction over two meters. It utilizes a cross tail for elevator that incorporates an all moving tailplane, so no wing to tail incidence problems. It has flaps for landing and a towhook could be added for winch or bungee launch, however this model is not designed for full on f3b launches. This model is not overly heavy for its size; weight and strength on this model is not an issue. This model has a fantastic, visible color scheme with stripes on the bottom and airbrushed on top and is also available in other colors.

Construction

For the radio installation, in the forward fuselage I marked out the radio gear with a felt tip pen and then proceeded to to cut the appropriately marked out area with a rotary tool and finished with sandpaper to neaten up the edges. The front of the fuselage has to be glued to the rest of the fuselage. This separation in componetry allowed a very easy start to the model, it was easier to work on a separate component rather than a whole fuselage. I used JR Nes 331 servos for the forward fuselage rudder and elevator controls and I used a small square 800mah, 4 cell battery pack to provide power. For the rudder control I made a carbon pushrod for this control and used a printed circuit board horn. Pc board is available from electronic stores and can be cut on a scroll saw if you are not concerned about blade life. The front fuselage was then complete and epoxied in place with 30 minute epoxy.

For the wings all that was involved in construction was the installation of servos, wiring and to attach control horns to the surfaces. This model has flaps and ailerons taking the servo count to four. I used JR Nes 331 mini servos that have approx 3.3kg of torque. It sounds scary but I have found that if a small amount of epoxy is used the servos can be glued in and removed using a pair of plyers and twisting the servos. The servos where then glued in place. I choose to have equal up and down movement on the ailerons and flaps as this provides the most programming option’s things like crow, full span aileron and flap to aileron mix are easily taken care of with this set up. The only downside is that it is dificult to get 90 degree flap on landing due to the aileron horn not being offset, however I am not competing in competition’s and don’t mind. I used threaded rod as pushrods and sheathed them with carbon fibre tube.To do this cut the threaded rod to size, cut the carbon fibre tube to the required length and attach with nuts on each end. Put clevices on the reinforced pushrod and the reinforced pushrod is complete. Sheathing can also be acquired by running cyano on the appropriately cut to size threaded rod and slide the carbon tube over the rod.

I then proceeded to balance the model using lead shot glued in with slow cure epoxy, this can be drilled out if the model is nose heavy. The batteries where cycled and checked and the model was prepared for flight.

Radio Programming

After setting the end points and setting sub trim, I programmed 70% differential on the Ailerons. Aileron 1 and Aileron 2 where mixed to provide Aileron control. Flaps were mixed together to provide flap/ crow braking.Crow was set with maximum down flap, as much movement as was physically possible. I mixed elevator to full span camber change, 2ml down at the trailing edge across the whole wing that is switchable on and off. I also mixed elevator to full span reflex on a switch, 3 ml upward at the trailing edge, this provides fast but not sharp turns by reducing drag. I also mixed crow to elevator to prevent pitch up on landing. I felt aileron to rudder mixing was not necessary. The last switchable mode was full span ailerons but this was not really required.

Flying

I went to a local slope and was not disappointed. I spent over an hour, in approximately 15 knots pushing this model as hard as possible, and did not come close to flutter or having any other problems. The model performs aerobatics well and with crow braking is easy to land. This model is fast and has no bad manners. Overall a good performing slope soarer with excellent, strong , molded construction.

Conclusion

This model flew well, was fast and was very easy to fly. Its minimal construction is a god send and it an excellent slope model. It uses a modern F3B wing section the MH 32, that has been very successful on larger models F3B models and did not disappoint with this model. It also utilises a cross tail that defeats any chance of incidence problems. I have no problems with recomending this aircraft as a high performance, high quality molded slope soarer, that is priced well when compared to other molded models of a similar size.

Lanyu Minimoa 5.33m

Introduction

The Minimoa is one of the most famous and well known vintage sailplanes of the era. This model is a fairly accurate replica of this aircraft. There is still several Minimoas flying around the world and the internet will provide details on these full size aircraft. This model is traditionally constructed utilizing fabric covering and laser cut componetry. This model is not greatly detailed in regards to scale fittings however the scope is there to detail these models. This model is large and heavy and has to pass inspection before flight, please contact your nearest large model inspector if you have any problems or queries during construction. MAAA inspectors can be found on the internet. You must also have the inspector at the model certification flight. This model is very large and if transport is an issue Lanyu models also make a smaller size Minimoa.

Construction

The first thing I did with model was to iron down the fabric with a covering iron and tautened the fabric as much as possible with a model heat gun. I gave the model a very light coat of thinned dope to seal the fabric. If you plan to do this only a very light coat is needed or you may have problems with excess shrinking damaging the airframe, also do not brush dope on to the painted surfaces, you must be selective with process, or, spray the thinned dope on painted surfaces with an airbrush keeping the airframe level so there is no runs. The fuselage was next and I cut appropriate tray for batteries and tow release servos, these were epoxied in place with an epoxy/qcell mix to allow for sanding of fillets that looks very neat when completed. The photos show the fillets unsanded. I used a dual battery backing system on the model for power to the radio gear and these items were mounted with cable ties available from your local electronics shop and epoxied in position. I chose to make my radio installation as low as possible to allow for a scale cockpit that will be added in the future. During construction of the wings I had my first minor drama. I accidentally cut the spoiler bay fabric out of the wing instead of using the area of fabric to cover the airbrake installation. After this disaster I made the choice to use large commercially available Graupner spoilers. This took time and recovering but worked out ok in the end. The spoilers fit into the model and work well on the bench. I then proceeded to mount the servos and to run long length leads down the wings to the fuselage. I also wired extension leads to the tip panels for aileron control. I used 11kg torque servos for the aileron controls, more torque is better on these large aileron surfaces, I wouldn’t use servos of less torque on this control. I used NES 517 servos for the spoilers, there is not a great load on the spoilers. The hatch covers for wing servos were then screwed in place to cover the servos. I used large Du-Bro plastic horns designed for large models which can be ordered from your local hobby store, these are made of very strong plastic and I have used them for a couple of years without a single failure. These horns were used on aileron, rudder and elevator. These horns are designed for large power models. The elevator requires a servo mounted in the elevator, one of the good things about this scale model is the use of servos on all except the rudder mounted close to the surfaces, this live control allows for very little slop in the controls and provides better accuracy for the controls. Also down the back is the rudder and I used a Hi Tec jumbo on this control, this surface is large and I wanted a strong gear train on this particular surface. For the aerotow release I used a commercially available Graupner release, available from Model Flight. I drilled the mounting in the nose and epoxied the release in place. I used a Hi Tec servo for the Aerotow release. I used two 5 cell Sub C, 2500mah soldier battery pack's for this particular model and these large custom batteries are available from Model Flight. Also available from Model Flight is the dual battery switch control. These large batteries will provide long flights and another battery in case of failure. I prefer redundancy on large models for safety, and I also prefer to add more batteries instead of lead. For the receiver I used a JR RS770s synthesized receiver which does not use crystals, lessening the chance of a failure due to problems with the crystal. It is now deadline day and I have this model very close to completion, I have to make wing root covers that I intend to make from light ply and spruce and cover with fabric. I also need to make a canopy frame, and cover the spoiler bays. Unfortunately the model is not ready for its initial test flight. Flying the Minimoa and radio setup will be in the next issue, from all accounts this model flys well. Rod Watkins from Victoria flew this sailplane at the Jerilderie Aerotow and was very happy with the model.

Minor changes to text Hayden Daley March 2009

Welcome to these DVD reviews, I would like to thank Paul Naton from Radio Carbon Art who contacted me by Email from the USA and requested reviews on these DVD’s and also Michael Oreilly from Model Flight for allowing for these products to be reviewed.

F3 Building Clinic

This DVD begins by explaining all the tools needed in the construction of a molded F3B type sailplane, glues, sanding tools and other items needed for construction are well explained. The brands and types of glues and other parts are shown allowing for the purchase of these or similar items before beginning construction. Next is the electrical equipment required before beginning construction, these include a soldering iron, solder and flux; and heat shrink material for wiring of different sizes and widths. Paul Naton also runs through the hardware required for wiring servos, ball links for control surfaces and suitable batteries to be used in these models. Next is a short section on radio gear. This DVD is based on different catergories which are recorded in chapters allowing the catergories to skipped to certain sections easily. V-tail construction and linkages needed for the V-tail are well covered. Next up is fuselage construction, it shows how to mount fuselage servos, how to mount a battery, how to construct V-Tail push rods and where to put switches. Next up is electricals, it shows construction of custom battery packs, what cells to use and what tools are required in construction. Next is testing of the newly constructed battery pack. Servo wire soldering is thoroughly explained; as is the soldering of plugs and fixtures for wing servos and this information is demonstrated with possible errors that can occur and shows how to test for possible poor connections. Diagrams are used to explain the electrical “system” in the sailplane and options available in wiring. Fuselage and wing wiring are thoroughly explained. The next part is the tasks required to finish the fuselage this includes nose weight, tow hook and aerial placement. The wing construction is well covered, servo installation on other tasks are well explained. There is much more to this DVD but you will have to purchase to get the rest, overall an excellent explaination of how to construct an F3B sailplane.

Available from

Radio Clinic

This DVD is an explanation of how to program modern computer radios for sport, as well as high speed performance style models used in competition. It begins with the goals to be achieved when programming models for efficiency and the reasons for the need of efficient setups in RC sailplanes. This DVD shows programming of 2 channel sailplanes right up to high performance molded models. Basic radio controls and there uses is covered. A thorough explanation of flight modes and there uses is explained, and the reason for the need of flight modes in modern soaring aircraft. The basic programming, model select etc are demonstrated and the settings needed for the basic set up or RC sailplanes. All the perimeters available in the radio used for demonstration are explained, sub trim, dual rates, exponential, flight modes and other functions. This DVD contains diagrams and more importantly the reason and needs for a particular setup in the model and how to achieve these settings with computer radios. The mixes like elevator / flap and other mixes are demonstrated and the need for these mixes and the percentages required when using these mixes. Radio clinic shows the set up of different models, essentially this DVD contains all you will need to know when setting up RC models and guides you through the programming sequences required to program modern computer radios. Radio clinic for sailplanes is a clear and precise, logical explanation of modern computer radio programming. There is much more to this DVD but you will have to purchase to get the rest!

Available from

High Performance Thermal Soaring

This DVD begins with the importance of weather and the ability to gauge weather when thermal soaring, this is clearly demonstrated with diagrams and shows how weather can affect the formation of thermals and there size. Gauging of weather forecasts is demonstrated by using information from websites and the ability to use these forecasts to choose the best times to thermal soar. The explanation of ground signs when thermal flying is excellent it explains the signs on the ground when thermals pass through a flying site. This DVD shows the importance of flight modes, the ability to change settings when soaring to allow for different flying conditions including a minimum sink setting flight mode when thermal soaring and the need for speed setting when returning from downwind. Trim settings and there needs when thermal soaring and also other trim settings are demonstrated. CG settings and the affect they have on the models performance and setups required, it explains how to set the CG effectively on high performance sailplanes and to adjust the radio for CG setups. This DVD covers the need for efficient flying, bank angles and the increase of drag that occurs with bank angles and the reduction in efficiency resulting in poor flight times; and the need for smooth efficient flying. All thermal soaring topics are well covered. Next up is David Hobby and he explains how he thermal soars, the techniques, the way the model reacts in lift by using a small model to demonstrate the model reactions in different conditions. David Hobby explains how to thermal downwind but his main demonstrations are based on the importance of staying in the core of the thermal when thermal soaring. Tactical and other information are also covered by David, in essence he tells you how to thermal soar and the way he does it. There is much more to this DVD, an informative well explained look at high performance thermal soaring.

Available from

Hayden Daley 2008. Minor changes to text 2009 and 2010

Thats it from the Thermal Circle, happy, safe and succesful soaring.

Hayden Daley 2010

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