Letters to the Editor

Frank –

Nice Start to your e-magazine! I am the newsletter and website editor for our club (Mid Missouri Radio Control Association, http://www.mmrca.org/) and I have linked to your magazine from our website. I will also put an article in the next newsletter. (ed. Thank you)

I am a relatively new pilot (2004 will be my second flying season) learning on A SIG LT-40. My instructor is a pattern pilot. He has been very thorough teaching me “straight and level flight” and to perform the oval pattern. I am a college professor and only have time to fly on weekends and then only when other family matters don’t take priority. This makes my progress slow, but hopefully steady.

 

As a new pilot, I have had a couple of frustrating situations that your e-magazine may be able to help with. I am frustrated with the lack of a clear list of the skills I need to acquire to become a “good” RC pilot. Do required skills include:

 

Straight and level flight
Oval pattern
Both left and right level turns
Taxiing
Lining up and flying straight down the runway (ed: Only when allowed by club rules.)
Learning slow flight
Judging distance and altitude
Crosswind flying and landing
Landing on both ends of the runway

Learning the landing glide path
Understanding the dangers of stalls

My instructor has been very good and stepped me through these from his own knowledge (ed. A good instructor). But after soloing, the general approach for most is to just go out and fly a bunch of stuff and learn things as you go. No working on developing particular skills, but just fly and learn as situations develop. This is fun, but may not be very helpful in developing into a better pilot.

In research on the problem as to what to work on next, I found in the AMA documents list on the AMA website, a list of skills an “introductory pilot”, a senior instructor, should be able to perform before attempting to teach a beginner pilot. This list seems like a good list of skills to work on next. My question is what should a “good” pilot know how to do proficiently and how can they go about learn those skills?

 

I will continue to ask my pattern friend questions, but he has invested a lot of time in me and that has taken time from his pattern practice. I do know from my work, that one of the best ways to really learn something is to teach it. It would be great if we could develop some guidelines and instruction material to help accomplish this.

I have noted that LSF (ed. League of Silent Flight.) has a set of self-imposed steps that members can work on demonstrating proficiency. This might be a way to motivate some to become “better” pilots and those that don’t want to do this, don’t have to.

 

Second, in the January “Model Aviation” Bob Hunt commented on the low number of people that compete. From my perspective I have two problems. The coverage in “Model Aviation” and in the rulebook, seem geared to those that already compete. This may have been done before, but a series of introductory articles to simply explain each competition and how to get started would be very helpful to beginners. (ed. We can have each organization contribute their special piece here)

 

Our club only hosts a pattern competition and that only started last year. They say that I can compete in Sportsman class but I am not comfortable with my basic skills enough to try things in front of judges. Maybe I will try it in a year or two. I know that I would improve quickly from this but I would like to develop those basic “good” pilot skills first.

 

I also have limited time to practice. Those with less practice are likely not to place well (ed. True) and that may be less fun (ed. Not true). In the early stages of learning to fly RC airplanes I think a skill accomplishment test would be much better as anyone that demonstrates the skill is considered successful. I hope these comments are useful and if I can be of help in clarifying them please contact me.

Dave Larsen

The Editor Reponds…

 

Dear Dave,

Thank you for writing us. You ask a number of intelligent questions and have some very good ideas. Before trying to answer some of them, please keep one thing in mind. The sport of model aviation, unlike full-size aviation, has no “governing body” that can act with the force of law as can the FAA. As such, any rules or regulations the Academy of Model Aeronautics (AMA) may suggest are just that, suggestions. The organization does its best, as you noted about the suggested minimum instructor ability “requirements.” But there are many individuals, with a great deal of modeling experience, that have other ways of teaching and requirements before soloing a new pilot.

With that in mind, the list of abilities you presented is indeed a good place to start. If a model pilot can easily perform all these “maneuvers” regardless of wind or various field locations ,then they are indeed an accomplished sport pilot. I would add just one other criteria; one many instructors have before even soloing a student. A student ready for RC soloing should also be able to recover his aircraft from any unusual attitude or position that is likely to occur once the student starts flying alone. Some few examples would be demonstrating recovery from a low approach, good missed-approach ability, recovery from over rolling a turn, power-off approach and landing plus a few others such as spin recovery.

A good sport RC pilot should be able to recover from ANY bad attitude or problem. This includes flying and landing, using rudder only without aileron control, in an aileron equipped aircraft. Other important items to know would be how to recognize a dying on-board battery and how to get the plane back safely; flying and landing a permanently out of trim airplane, how to land a scale or high performance aircraft and crosswind landing techniques.

Not every model pilot is willing, or even wishes to, learn all these maneuvers. This is fine. One good thing about model aviation is that there is room for everyone and everyone can progress at their own pace and to their own chosen development level. For those wanting to advance their flying skills, it is all there for them. Just plan each flight ahead and then perform the maneuvers you have chosen. In the next few months, Sport Aviator will present various aspects of the skills outlined above and in your letter. We have already started with “Landing Techniques” and “Loops.” We will even take your suggestion about trying to develop a list of suggested skills to master and techniques to teach. But we already know that this task will be like debating the infamous “downwind turn.” We will start this project as soon as I can get my Kevlar vest and crash helmet on.

As for competition, you and Bob Hunt are right. But remember that not everyone wants to compete. Most model pilots enjoy modeling for its own personal rewards, individual challenges and the friendship of all the great people flying model aircraft. Personally, I can think of no better 3 reasons to fly models. Competition, and the work and devotion it requires, are just not on many model pilots’ need-to-do list. Sport Aviation has many rewards all its own.

For us crazy competition pilots, (my own vice is Masters Pattern), the time and energy we put into making that perfectly round loop is the major reason we fly models at all (except for the great friends we make). To us, it is not the competition itself, but the exacting piloting skills that competition demands that fuels our modeling drive.

Do we become better model pilots because of competition? Heck yes, and that is another benefit. But can sport pilots also become better model pilots by pushing their own ability horizons while sport flying? Double Heck, YES.

The wonder of model aviation is that this one sport really can accommodate all. Thank you for your ideas and suggestions. Look for the promised articles and please continue to contribute your thoughts.

 

Sincerely,
Frank Granelli

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I think your new teaching section (Sport Aviator) is great. I read your article on landing and it was very helpful. As a new to semi-new member to the flying world, I have some input that might be useful.

A glossary of terms that could be downloaded would be a big help to the new pilot when reading any lessons or articles. Any conversion charts that may be available would also be helpful.
Charts that explain what size motor would be needed for a plane. Charts that could be used to tell what size 4 stroke has the same power as a 2 stroke and what the difference is. Why a certain size prop and pitch is used on a particular size plane?

Since I am new at this and don’t have some of this information I feel it is needed for the new pilot before all of the other items. 

Thank you for your time,
Walter Forsythe

The Editor Reponds…

Dear Mr. Forsythe,

We will eventually publish a glossary of terms as more technical terms are printed. For now, and maybe even easier to use than a glossary, we are printing all technical terms in blue. Clicking on these terms will bring up the definition. There is no need to move from the article being read to a glossary to find out what an unfamiliar term means. With this method readers who already know the term’s definition, do not have to wade through a parenthetical definition (i.e. what the word means) inside the article itself.

Your chart selections are a good idea. We will try to work on the engine/prop/aircraft chart and to explain some of the performance differences between 2 and 4 stroke engines. 4-strokes are somewhat problematical to rate as there are several different types. A supercharged YS 63, for example, has more horsepower than a normally aspirated 90. But the 63 still has less torque than the 90 and therefore, cannot turn a propeller as large as can the 90.

Thank you for the suggestions and we will work on a descriptive engine article in the next few months. Please let us know any other suggestions you may wish to share.

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Dear Sport Aviator,

I have just finished mounting Great Planes floats on my Hobbico Super Star. I have a rudder on the back of the left float. My problem now is how to run a push rod from the plane’s rudder servo to the float rudder.. The rudder servo is about 8 inches above the float rudder attachment and about 12 inches  in front of it. I can anchor the push rod to the bottom of the fuselage and to the top of the float, but I think it will flex when pushed. Do you have any sketches or instructions that will help me?  Thanks four help with a previous problem.

Bob Murray

The Editor Responds…

Dear Bob,

Actually, you do not need to run the float rudder control directly from the rudder servo. Your SuperStar has a nose wheel with brackets. Even if you removed the nosewheel strut, you can use a small 5/32″ landing gear wire strut in the nose gear bearings. (Most conversions just remove the nose wheel from the wire strut and use the bare strut to actuate the rudder.

Take a 5/32″ wheel collar, remove the small screw and replace it with a 2″ long 4-40 screw. screw a plastic screw-on control horn, usually found on the ailerons, onto the end of the long 4-40 bolt. Mount wheel collar onto the end of the nosewheel axle or onto the straight wire if that was used instead of the regular nosewheel.

Then just make up a control rod from a 1’4″dowel and threaded wire. Screw a clevis onto both ends. Connect the front end of this control rod onto the nose gear plastic control mount and the other to a nylon control horn on the water rudder.

With this technique, converting from land to water or back again, takes only a few minutes since none of the float equipment is permanent.

Good luck,

Frank Granelli

 

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I have read several articles on wing washout and still am not sure the direction of the leading edge required and why washout is important.
 
Ken

 

The Editor Responds…

 

Dear Ken,

“Washout” is a strange name for an aerodynamic system and is therefore somewhat confusing to everyone.

Basically, wing washout adjusts the wing’s leading edge’s angle of attack to the oncoming air to help make the ailerons more effective at slow speeds. An airplane’s wing, depending on a few factors, usually stalls (loses lift) as the leading edge gets more than 20 degrees above the horizon, without power at slower airspeeds.

Since ailerons operate by adjusting the amount of lift for each wing half, they lose effectiveness if the wing is not producing any lift (stalled). In a stall, a straight wing has no aileron control and level flight may only be maintained by the rudder.

Wing washout lowers the leading edge (pointing it downward), only in the outboard wing section near the wing tip, by about 2-3 degrees. Therefore, while the rest of the wing is stalled at a 20 positive angle of attack, the outboard wing section is still “flying” since its attack angle is only 17 degrees (20 deg. minus the 3 deg. washout). As the ailerons are located in the outboard sections, and that part of the wing is still producing some lift, the ailerons remain somewhat effective. That is the theory behind washout.

What is the reality? For scale models that usually have outboard ailerons only, washout can be very effective. After all, it was invented for full-size aircraft and should remain effective on a miniature version. For sport models that have ailerons across nearly the full wingspan, washout has less effectiveness. By lowering the angle of attack at the tips, the wing produces less total lift then would a straight wing. That is the price for having washout.

Since sport model ailerons are so large and powerful, they remain effective right up to the stall point. True, they do lose all effectiveness at the stall, but by then the model has stalled, pointed nose down, and started to regain flying speed. The ailerons immediately regain effectiveness. It is the designer’s choice to use washout in a sport model and always a compromise trading total lift for extra aileron effectiveness at slow speeds.

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FONT face=Arial size=2>Dear Sport Aviator,

 

I really enjoy the Sport Aviator magazine. Lots of good stuff there.
Any chance of an article or some information on in cowl mufflers? I am
building a Piper Cub model and am having a problem trying to get the
right in cowl muffler selected for the OS .46LA engine I have installed.
Keep up the good work.
Thank You
Bob Wert

The Editor Responds…

Dear Bob,

 

Thank you for your encouraging words about Sport Aviator. They are greatly appreciated.

 

In-cowl mufflers would be a very difficult article topic as aircraft, engines and after-market mufflers vary too much. Still, we will take a close look at the subject to see if it can be done.

 

For now however, we suggest you contact Bisson Mufflers www.bissonmufflers.com as they have an extensive line of suitable Pitts style in-cowl mufflers as does Slimline Products www.slimlineproducts.com 

 

You may also wish to check with Tower Hobbies as they have several in-cowl muffler systems for some of the OS engines they distribute. Re not sure if the LA 46 is included.

 

We hope this is of some help to you. Thank you again,

 

Sincerely,

Editor

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I have three questions:
1. Why is it hard to make right hand turns?
2. Why does the engine stall whe I took glow driver off the glow plug?
3. What tells me what direction to go on the needle valve when I want to make adjustment – lean or rich?

 

Thank you,

Gorman4

 

The Editor Responds…

The high-speed needles on ALL model glow engines all work the same way. Turn the needle clockwise to lean the mixture and counter-clockwise to richen it. The proper setting for non-pumped engines (almost all model engines today) is about 500 rpm richer than peak rpm.

 

If the engine slows slightly when the glow plug is removed, that is normal. Most engine “heads” (the top part) do not reach operating temperatures until they have run for a minute or so at mid- to high speed. Most modelers remove the battery before operating head temperature is reached and the slightly cooler head takes some of the heat from the glow plug causes the slight rpm loss.

 

This loss should never exceed 1-200 rpm. If the engine slows more than that, or if the transition from idle to high speed becomes difficult, then the glow plug must be replaced. Slowly advance the throttle from idle to high speed. If the engine goes rich, stutters and refuses to accelerate, suspect the plug first. This applies of course, only if the engine has been properly adjusted and has run fine before the problem occurs.

 

Most model pilots are surprised to learn that just one lean run will kill the glow plug. On the other hand, when run with proper mixtures, a glow plug will last for years in most sport engines. Honestly, I have nearly a dozen aircraft that fly every year, and every one of their glow plugs is more than five years old. Some are nearer 15 years old and still working well.

 

Right turns are more difficult for a few reasons. First, most student pilots learn left turns first, so right turns are new. Their perspective is different. Second, Due to engine torque trying to rotate the wings to the left, right turns require a bit more aileron to reach the proper bank than do left turns. As a result, most student pilots apply a little right aileron, see that the aircraft is rolling more slowly, and apply more aileron (sometimes this is done subconsciously). This causes the bank to be too steep and we all know that steeply banked turns are harder to do.

 

Finally, most pilots are right-handed and therefore, usually right-eye dominant. Right hand turns performed on the pilot’s right side (the usual practice for right side landings) puts the model nearly out of frame to the right for the dominant eye. Left hand approaches put the aircraft out of frame for the left eye, but in full view of the dominant right eye. Try it, you will find that right hand turns done on the pilot’s left side are easier to do than the ones on the right side. So, to learn right hand turns, learn than on the left side, about 150 yards out from the flight line in full view of the dominant right eye. Left-handed pilots, or course should reverse this process. 

 

This last reason is mostly my own opinion, but has seemed to prove out in practice over many years. I offer it for what you think it may be worth.

 

Frank Granelli

Editor

 

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What would happen, if the ailerons are changed from the manufacturer’s configuration to servos with 180 deg. horns and straight push rods? This was done to my NexSTAR on the advice of one of my trainers. The leading edge of the wing had to be raised 1/4 in. It flies well but why was this necessary?

 

The reason for this as explained to me was that it flew mushy and “squirrelly” with all the junk removed. I really don’t understand that but it worked. There was also something about the incidences and what is it supposed to be.

 Jerry Lamb

The editor responds…

Dear Jerry,

 

Thank you for visiting Sport Aviator. I am not sure what changes your instructor made to the NexSTAR. But possibly the 180 degree servos were installed in the wings, in place of the single center servo, to increase the aileron’s movement.

 

With its drooped leading edges in place, the NexSTAR remains flying even at 6 mph. The ailerons lose effectiveness at this very low speed and perhaps your instructor felt that more aileron movement would help this problem. It didn’t for me as 6 mph is just too slow to ever expect ailerons to have much authority.

 

A for your wing incidence change, our test aircraft never hinted that such a change would be required so we never tested this area. The NexSTAR tracked well, proved stable in pitch and had sufficient lift with the factory set wing incidence. I am happy that your aircraft flew well in that condition, but that might be more a testament to the NexSTAR’s good design than to its being a requirement.

 

As we noted in our review, and follow up article, the NexSTAR had one strange flight characteristic, the roll rate was not symmetrical. The second half of the roll was much faster, with constant aileron input, than was the first. It may be that your instructor was trying to eliminate this characteristic.

 

As the follow up Sport Aviator article notes, removing the leading edge cuffs and flaps makes the NexSTAR fly like most any other trainer. If its roll characteristics bother you, you may want to remove the leading edge cuffs.

 

Regards,

Frank Granelli

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I have a Top Flight Corsair kit and am interested in an alternative way to finish it other that plastic film covering. Do you have any ideas and how?

 

Also, I have a flying question. The Corsair has a tendency to tip stall at slow speeds, so will it actually help to takeoff with flaps extended as in real life to improve slow speed flight?

 

Sincerely,

 

Bruce Perkins

 

The editor responds…

 

Dear Bruce, 

The closest thing to plastic films in application ease is Coverite. Coverite is a strong fabric that uses heat to shrink and stick, just like the plastic films. Coverite comes in colors, or in white that can be painted. Check with your local hobby shop for details.

 

My experience with the Top Flite Corsair did not include tip stall problems at low speeds. Please check your CG , lateral CG and the amount of elevator throw. I do remember some tip stall at speed if the elevator had excessive movement.

 

Flaps in a model are great and do help reduce landing speeds and steepen the descent curve if the aircraft flies normally otherwise. But it is not a good idea to use flaps to overcome handling problems. Since the pilot is not in the aircraft, It is hard to “feel” when the flaps are approaching the limit of their ability to solve a tip stall problem. The result is usually a more severe stall than if the flaps had no been deployed.

 

Try solving the problems first, then use the flaps to enhance your Corsair’s flying envelope. Thank you for visiting Sport Aviator and I hope this was of some help.

 

Regards,

Frank Granelli