Radio Control Aerobatics - 2007/07
Eric Henderson [email protected]
If you are new to RC Aerobatics, you might need a stepping-stone model
Many RC pilots’ mission is to improve their aerobatic flying skills. A common belief is that you have to fly an Aerobatics (Pattern) airplane to learn and perform aerobatics.
I often review models apart from this column that are not specifically designated as “Pattern” airplanes. I also build a large number of sport aircraft for myself and members of local clubs. Those models keep me in touch with what pilots at a typical local field are buying. Flying all those different designs often reminds me of the differences between Pattern and sport airplanes.
On the surface the current sport ARFs tend not to show their potential as really good Pattern models. It is not obvious by just looking at them what is underneath the surface. More times than not there is little difference between the aerobatic capabilities of a sport airplane and a Pattern airplane.
It is common logic that you need a purpose-built and/or -designed Pattern airplane to fly precision aerobatic schedules and maneuvers. This logic misses a huge step in pilot development.
There has to be a time when you learn to fly. It logically follows that there has to be a phase during which you learn to fly aerobatics. Another stage is when the rudder has more function than just steering on the ground. Then there is a phase in which you take command of your airplane and put it exactly where you want it at all times!
Logic is a good process, but it is not law; we can easily challenge the concept of using a Pattern model to learn aerobatics. How about inserting the need for a stepping-stone airplane? It would be relatively inexpensive, easy to fly, and capable of aerobatics. It would not have to qualify for precision Aerobatics competition. In this logical progression you are not there yet.
A huge number of sport and scale aerobatics airplanes can be used as this stepping-stone. You can use these to develop your aerobatic skills long before you are ready to compete or spend your hard-earned cash on a competition aircraft.
The stepping-stone logic allows you to consider a whole series of readily available ARFs. You may already own one that can more than satisfy your pre-Pattern desires and needs. You can also choose an airplane because you like the way it looks or how it fits your budget.
Examples of stepping-stone models
- Hangar 9 Ultra Stick
A popular sport model is the Hangar 9 Ultra Stick. It comes in several sizes to meet different budgets. I recently put together the 40-size versions for an AMA Sport Aviator online review.
This model is inexpensive, and an Evolution .46 engine will pull it straight up and out of sight. It flew well with lower-cost “standard” servos, which provided all the accuracy and guidance required.
The Ultra Stick comes with several aileron/flap options but could be built as a fully aerobatic four-channel model. Not only did it go straight up, it tracked straight in loops and did great slow rolls and four-point rolls.
You have a unique opportunity to see this airplane fly on the Internet. You can look up the Ultra Stick review at www.masportaviator.com. This AMA-sponsored website is free to all comers. The reviews there often contain downloadable video clips of test flights.
One of the clips shows the Ultra Stick doing extremely slow rolls with no problems at all. It has great performance for a sport model. It means you can learn to do slow rolls with an airplane that will be on your side. You could easily use this model to hone your precision aerobatic skills.
When asked to do a spin, the Ultra Stick was easy to enter and exit on command. It is also a friendly airplane to take off with and land precisely. Snaps were pretty and acceptable. The price is right, and the best part is that you do not have to do anything special to get one to fly right.
- Great Planes Ultimate (larger biplane)
There are no real restrictions in this pre-Pattern logic. You could consider several of the scale biplanes out there. Some Pattern biplanes are currently competing at the World Championships level.
If you like a larger biplane, the Great Planes Ultimate is excellent with super handling. The model I finished and tested sports an O.S. BGX engine turning a Mejzlik 20 x 8 propeller. This potent combination easily allows you to do all maneuvers up to and including those for FAI international competition.
The Ultimate is a pre-Pattern airplane because it is too big and too heavy to meet Aerobatics rules. But this is not a problem because we are working on our aerobatic skills, so we can fly the pants off of it with impunity.
- Hangar 9 ShowTime
Are there sport airplanes that are the right size and weight for aerobatics competition? The Hangar 9 ShowTime meets all Pattern-competition size and weight specifications.
I built a ShowTime this year and grafted an O.S. 1.08 onto the front. This combination has tons of power but was perhaps a bit on the loud side for competition.
However, that need not be a big concern, even if you intend to try a Pattern contest with this combination. Pattern event CDs really want you to come to their events. It is common practice for them to waive the Pattern-contest noise requirement in the Sportsman (AMA event 401) entry-level class. They want you to try competition and hopefully get serious later.
As long as you meet the host club's standards, the event directors usually invite you to fly your "sport airplane." It can't hurt to pick up the phone and ask. Once you attend a contest, you will learn more than I could ever write here.
If you want a model that looks and sounds a bit more like a Pattern airplane, the ShowTime would be perfect with something such as a YS 1.10 engine or an electric motor for power. Four-strokes tend to be quieter with standard or aftermarket replacements.
The ShowTime I built and tested flew great once I moved the CG forward approximately 1/4 inch from the recommended 3-D position. The supplied side force generators were not fitted. The model weighed more than 8 pounds.
It went straight up with no help from the transmitter. It needed only a teeny bit of down-elevator trim mix at the low-throttle setting to correct a down-line pull to the canopy.
Axial roll performance was easy to extract from the ShowTime. Only small amounts of rudder input were required to keep the nose up on a slow roll. Knife-edge flight was excellent, so the first and third points of a four-point roll could be held with comfort.
The ShowTime entered spins with authority and would do them with rudder and elevator inputs only. The best part was that the spin would stop as soon as the controls were returned to neutral. This lets a pilot quickly learn how to stop a spin with the wings exactly where they should be.
This airplane is simple to assemble because it has plug-on wings and stabilizers. You just set the control throws at the recommended low rates. These work well for Pattern flying. Then if you feel the need to bust loose a little bit, you can go to high rates and let her rip!
- Great Planes Pitts Special
My most recent build was a Great Planes Pitts Special. The full-scale version is famous around the world for its winning performance at all levels of aerobatic competition. The Great Planes aircraft is intended to be a really good scale-version sport model with similar capabilities as its full-scale counterpart.
The Pitts Special is marvelous to fly and looks fantastic as it roars through the air. I would not call it an easy airplane to fly. Yes, you can do all the maneuvers in the Aerobatics book, but you need to work at them much more than with, say, the ShowTime or the Ultra Stick.
The Pitts is a bit tricky to take off with and land if there is any crosswind. It also tends to "wind up" into a snap. This makes it hard to time the precise moment when you want to stop with wings level.
How to evaluate pre-Pattern potential
A good way to find out if you have an airplane with pre-Pattern potential is to ask a Pattern pilot. However, it is not that hard to figure this out for yourself. Basically, if the airplane makes maneuvers feel comfortable or easy, you have what you need.
Radios and new technology
Spektrum and Futaba 2.4 GHz radios are available now. Spektrum 2.4 GHz upgrade modules are available for Futaba and JR computer radios, and Futaba has announced its own module upgrades.
Aerobatics pilots, by the nature of their sport, are picky about their equipment. But they are almost magnetically attracted to any new technology that is either "cool" or may give them a technical advantage.
Early reports from the Pattern world indicate that the new equipment is working well for electric and glow models. The reported immunity to radio interference is a big plus for all of us. Some different receiver antenna installation is required, but modern Pattern-model fuselages have plenty of room inside.
Frequency control at a contest may be slightly different. And I am not sure how the rest of the world is handling this technology. I don't know yet how it will work if you go to a World Championships or travel with your RC equipment to other countries. Meanwhile, we are all beneficiaries of a great technological development.
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
