Products - Frequently Asked Questions (FAQ)
I really like your kit, but I'd like to (insert change here). Can you help me modify your model to (insert changes here), such as installing a larger engine?
We cannot recommend exceeding our engine recommendations or making other modifications to our models. Power recommendations are made based upon a variety of factors, including size, weight, fit, thrust, torque, and stress testing of the model. Even if a larger engine may fit on the airframe, that does not mean it is a good choice for the aircraft. Exceeding our engine recommendations voids your warranty and exposes you and those around you to additional risks. Likewise, chosing to use an engine smaller than our recommended engine range may provide the aircraft too little airspeed to fly safely and again voids your warranty and creates unnecessary risk.
When will you come out with a (insert model type here)?
Unfortunately, we are not able to provide any information on future releases or planned future kits. However, please use our Product Suggestion Form, which will be forwarded directly to the appropriate product managers for future consideration. Thank you for your time and interest! We take your suggestions seriously, and use consumer's suggestions in our considerations for future products. Please note that our design cycle is long and planned well in advance, and that a model needs to have good popular appeal for us to seriously consider it.
I heard about a new product which is not yet listed on your web site. How can I get more information?
If a product is not yet listed on our web site, chances are good that we do not yet have information on that newly released product. Please visit your favorite hobby shop and our web site regularly for new technical information as it becomes available.
Where can I find scale documentation to complete my model?
An excellent resource for scale documentation for your project is:
Bob Banka's Scale Model Research
This is Bob Banka's Scale Model Research, a huge scale modeling resource who sells photopacks and other documentation which is enormously helpful.
Can you tell me how fast this model goes?
Unfortunately, we cannot estimate speed of our models. Speed is dependent on a large variety of factors, with the key one being engine and prop selection, but also including engine break-in, altitude, humidity, temperature, fuel and plug, assembly accuracy and, of course, pilot skill. Please remember that if your model does not fly as quickly as you had anticipated that prop selection can make a huge difference. High diameter low pitch props are like low gear in your car - providing you lots of pulling power off the line (great vertical) but very little forward speed. Low diameter high pitch props are like high gear in a car - lots of top end speed, but poor acceleration off the flight line and poor vertical climb.
I'm looking for a (insert aircraft type or skill level here) airplane. What do you recommend?
Please contact product support with detailed information regarding the desired application, pilot's skill level, etc.
I am interested in mounting your float kit on a model that does not have instructions for floats. How do I know where to position them?
Locating the floats and setting the proper incidence is the most important step.
Where can I find the specific set up information for (insert kit name here), including control throws, center of gravity, and incidences?
Please refer to our chart which lists all of that information for both current and discontinued kits and ARFs.
The manual for my model tells me to balance the plane laterally by picking it up by spinner and fin and seeing if it drops a wing tip, then add weight to the light tip to balance. Why do we do this?
Many things can cause an airplane to be out of balance laterally (from left to right), but usually the reason is very simple - an engine does not weigh the same from left to right of the aircraft because of mufflers, etc, and therefore the other side needs to be weighted appropriately to balance the plane this way. Balancing laterally is very important because an airplane that is balanced laterally will usually stall straight ahead and be very predictable and easy to handle at landing speeds. An airplane that is heavy on one side will drop that wing when it gets too slow to fly, increasing a possibility of a crash.
The model I am building says to place the spinner nut X distance from the firewall. I am using an engine with a small, light case which is not long enough and I can only get Y distance from the firewall. What do I do?
Most manufacturers try to provide a universal engine mount which will fit all engines in the size range at the time of the production of the model; however, in our quest for lightness, many manufacturers are now managing to produce ever smaller, lighter engines. Simply place shims between your firewall and motor mount to properly position your engine as instructed.
I am looking to get into flying remote control airplanes. How do I get started?
WELCOME TO THIS GREAT HOBBY!!
The first step is to locate a hobby shop in your area (use the dealer locator and enter your U.S. zip code), and to ask the local shop to refer you to a club in your area as well. In major metropolitan areas there are usually several, so you often have several places and groups of people to choose from. These 2 contacts will be invaluable to you in gaining first hand knowledge and support.
The next step is to visit the local field and watch people fly. Some clubs have a club trainer plane so you can gain a few flights before expending any money to find just how much fun this hobby is.
At this point it is time to join the AMA (Academy of Model Aeronautics, www.modelaircraft.org), which provides you insurance in case of accident or property damage with your model as well as an excellent monthly magazine. The cost is small and the protection is very important. Don't miss this vital step.
We STRONGLY recommend a simulator to help you learn to fly. Great Planes RealFlight R/C Simulator (www.realflight.com) is the best simulator and if you use it as a real training tool can save you a lot of time, money and frustration in learning to fly.
Once you're ready to 'take the plunge', we recommend you select an aircraft, radio and engine that best equates what your selected instructor uses. This will make it easier for him/her to assist you along the way. In particular, be sure to select your radio so that it is compatible with your instructor's radio so that you can use a trainer cord to help you learn to fly and help protect your investment. There are many directions to go in selecting a plane — for some modelers building is the most exciting part, and they select aircraft such as the Great Planes PT40 Mk II model kit to assemble. For others, they want to get in the air fairly quickly but are on a budget. In those cases, a plane like the Hobbico Superstar ARF makes a great choice. Others are short on time and want to be flying as quickly as possible, so they select an aircraft such as the Hobbico NexSTAR, which is almost entirely preassembled, with engine and radio already installed!
Please recognize that leaning to fly a model aircraft is a very challenging skill. Just as it would not be a good idea to try to teach yourself to drive an automobile alone in city traffic, it is an equally poor idea to attempt to teach yourself to fly. Model aircraft are amazingly responsive, and it is easy to get disoriented and lose control of your aircraft. For your safety and enjoyment, and for the safety of those around you, we strongly recommend you join the AMA, find a local club, and work with an instructor you trust. Similarly, it is always best to begin your instruction on an easy to fly trainer type model, and not attempt to fly more complex models until you've mastered the basics.
Good luck and again, welcome to our great hobby!
I used to own product X. I can't find it on your web site now. Do you still make it? If not, will you produce it again?
If the product you are seeking is anything other than an accessory or repair parts for another item, then unless a product is brand new, if it is not listed on our web site then the product is no longer produced. Unfortunately, we cannot answer whether or not a product will be reproduced in the future. Please see our discontinued products FAQ for more information.
I am replacing the motor mount, or making other repairs to the my built aircraft. How can I install new blind nuts since I can't get my hand to the back of the firewall?
This is a fairly common problem when installing a new engine, or completing repairs. To install new blind nuts, drill your new holes if needed. Slide a long pushrod which is the same thread as your engine mount bolts through the hole in your firewall far enough so you can access the end of the pushrod easily from your wing saddle. Screw the blind nut onto the pushrod (now in your open radio gear area), and pull the blind nut into position in the firewall. Use your engine mount bolts to pull the blind nut securely into position.
The kit I am building calls for metal pushrods from the rudder and elevator to the servos. Am I going to have problems with the antenna running through the tail of my fuselage with these metal pushrods?
You've asked an excellent question! Metal pushrods are a standard of this industry and are not a problem whatsoever, SO LONG AS you do not get your antenna intertwined with the metal pushrods or with servo leads. If you cannot run your antenna on the outside of your aircraft, run your antenna through a plastic pushrod outer or paper tube to keep it away from the metal pushrods and any servo leads you may have extending through your aircraft.
How can I make a professional gapless wing saddle?
Making a gapless wing saddle.
1. Cover the top of the wing center section with scrap MonoKote and shrink it tight with a heat gun. This is important as you want a smooth finish after the next few steps. Wipe a VERY light film of Vaseline over the covered part of the wing to act as a release agent.
2. Apply 3/4" masking tape to the sheeting on the outside edge of the fuselage wing saddle (not to the wing mating surface of the saddle itself). Position it as close to the edge as possible so you won't have to do much sanding later.
3. Mix about 1 oz of 30 minute epoxy in a Dixie Cup and add about 1.5 ounces of Micro Balloons or Talcum powder to the mixture. Stir it in throughly until you have a smooth paste.
4. Working quickly, spread this paste onto the left and right wing saddle, coating the outer half with a thick layer. Don't worry about coating the entire surface as all you should be concerned about is the outer edge.
5. Carefully mount the wing and secure the wing bolts. Some of the epoxy paste will be squeezed out of the saddle. Use a piece of scrap balsa to squeegee the paste into any remaining gaps and then scrape off any excess from the fuselage sides before the paste cures. It's not necessary to get it all off, but working clean helps minimize sanding. Allow the paste to cure for a couple of hours... overnight is better still.
6. Remove the wing bolts and pop the wing loose with the palms of your hands. Pull off the masking tape from the fuselage and remove the film from the wing. Using fine sand paper and a sanding bar, lightly sand the hardened paste from the outside edges of the fuselage, blending it with the fuselage contour. Check the fit of the wing to the saddle. If you have not overdone the sanding you should have a perfect fit without any gap.
My aircraft flies beautifully, but I just can't get it on the ground. It floats and floats right past. What can I do?
Many full size aircraft, like the Beech Bonanza for example, do float and have long glide paths. So do many models, especially lightly wingloaded ones. First, be sure your model is properly balanced (both CG and laterally to avoid tip stalling at slow speeds.) One trick, if the model has them available, is to use flaps (or flaperons). Also keep the nose slightly high almost to the runway (practice this at safe altitudes of course, until you know your model's stall characteristics well). Control forward speed with power. Touch down on the mains and then immediately lower the nose wheel. A higher diameter, lower pitch prop will also slow the aircraft down at all speeds, including idle speed. A low enough pitch will actually behave like an air brake (for example, 12x4 on a 46FX), so be sure to experiment with it at safe altitudes and familiarize yourself with the aircraft's new glide path prior to attempting to land. Lastly, how heavy is your model? If it is close to the suggested weight you could also add a little weight without effecting flight performance.
I am interested in an electric motor which rotates the opposite of a standard motor. Can I just reverse the polarity to reverse the motor's direction?
Because of the timing of the magnetic field with respect to the brush orientation it is not recommended to just reverse the polarity of the electric motor to run it backwards. This will cause the motor to run hotter than normal, it will be less efficient and its life will be shortened. To safely run the electric motor in reverse you would have to adjust its timing, which is only possible on certain motors. If the electric motor you have does not provide instruction to do so, then do not attempt to reverse the direction of the motor. Purchase a reverse direction electric motor for your installation instead, or consider a different gearing combination to provide you the right end result.
I am thinking of installing an engine inverted. What do I need to know?
There are a few things to know about the nature of setting up and running any engine inverted. RC engines are small, lightweight and fairly simplistic engines. They do not have all the complex equipment available to competition aerobatic full size aircraft engines or similar machines; therefore, when asked to run in inverted mounting, sometimes they can be a bit more challenging to set up than an upright installation.
First, realize that your engine may be full of fuel PRIOR to starting, risking hydrolock which can do severe damage to your engine, especially if the aircraft has been stood on its nose or even just nose low during transportation. Always flip the prop over to check the compression prior to using a starter. If it seems harder than normal, remove the glowplug and flip through several times or spin the engine with an electric starter to clear it and avoid the possibility of hydrolock.
Next, ALWAYS follow your manufacturer's instructions on engine break-in. In almost every case, the engine should be broken in on a test stand where it can be properly watched, cared for, fueled, drained, and adjusted easily and safely. If your manufacturer recommends in flight break-in, just be aware that it will be soft on power until the break-in period is completed and always be prepared for a dead stick landing during those break-in flights.
Then, once it is broken in, it can be installed. In some cases tuning in the inverted installation is a little more challenging due to the tank/carb relationship combined with the inverted mounting. If this is the case, tuning with the aircraft inverted/engine upright will help get the engine running flawlessly, then it can be run inverted.
Finally, some engines, especially inexpensive bushinged budget engines, will not like to start in an inverted position, again due to carb/tank positioning and fuel flow. In those case, you may need to start the aircraft inverted and turn upright to fly when running.
Do you offer a wing kit/fuselage kit/tail kit for my built up wood aircraft?
We do not sell fuselage kits or tail kits for any of our models. We DO offer the individual parts so you can purchase just those items you really need so that you do not have to purchase an entire kit when you only need a few individual parts for repair. Note that if you need to replace an entire fuselage, or even most of one, starting from a new kit may be quicker, easier, and provide you a better product in the end.
We offer wing kits for a select few of our models, because wing damage due to a rough landing or crash is most common. We offer only those our customers have regularly requested. A wing kit is everything which came in the original kit to build a new wing, including all hardware, plans, and a manual. Again, you can purchase just the individual parts if you do not need the entire kit.
I am building my aircraft, and can't seem to find the hinges. Were they missed in my kit?
It's possible your hinge material may not have been packed, but many people just don't recognize the hinge material. CA hinges come in a 3" x 9" strip in your kit and must be cut to size for use on your model. You may confuse this for fiberglass reinforcement tape, as it is fairly thin and somewhat flexible. CA hinges are an exceptional hinging material which fits in a thin slot, bonds very well to balsa with CA, and remains flexible and operational for a very long time if properly installed and cared for.
Can I use kit parts for an ARF and ARF parts for a kit? For example, can I put the CAP 232 kit's canopy and cowl on the discontinued Great Planes CAP 231EX MonoKote covered ARF (GPMA1230)?
In MOST cases, an ARF model is not identical in construction to a kit model. Because of this, the parts are generally not interchangable. In some specific cases, they ARE interchangable. For example, the CAP KIT's cowl is a direct fit (but not preassembled); the CAP KIT's canopy can be used on the 231EX ARF, but only if you follow these steps:
(If you purchase the canopy, GPMA2150, these instructions are included.) DO NOT cut on the front or rear cut lines. Simply cut the front and rear caps off so the canopy is as large as possible. Test fit to your model. You now need to decide - you can cut the canopy on the cut lines, but notice how the canopy will have to be glued flush to the inside of the dash panel and the inside of the cockpit back. This glue seam will have to be perfect to ensure your canopy remains on your model through the rigors of flight.
Instead, we recommend the following steps:
How do I use CA hinges? Is there anything I need to know to use them properly?
The CA hinges work wonderfully — if used properly, they have minimal gap, require little effort in installation, and are super strong and durable.
Things to remember:
I am getting ready to install a gasoline engine in a large model aircraft. What do I need to know to avoid radio noise from the ignition system?
In setting up your gasoline engine's installation, there are several important factors to remember:
What is the best way to solder braided cables onto couplers?
The method we like to use is as follows. First, make sure your soldering iron is very hot, a 100 watt iron will probably not get hot enough. Then, pre-solder the cable so that the end is totally silver, but not saturated with solder. Make sure to use a fair amount of paste flux. Then, put a small amount of solder in the bottom of the coupler. Once both pieces are ready, cover the end of the cable in flux and place it in the coupler. Then, heat the coupler until the solder becomes fluid and place a small amount of solder on the rim of the coupler. Using this method does make both pieces very hot, so you will want to hold the parts with pliers until they are cool enough to touch.
How do I solder heavy gauge wire?
Soldering heavy gauge wire is one of those things that is an acquired skill. Like many things, once you learn it, it becomes relatively easy.
Silver solder will produce a MUCH stronger joint. It comes with a liquid flux. It is more sensitive to the correct temperature and it is also more expensive.
Start by making sure the wires are very clean. We recommend sanding them where they are to be soldered with 150 grit sandpaper. Then clean them with alcohol (isopropyl, rubbing alcohol). After they dry, tack glue the wires together, using as little CA as possible.
Next, coat the wires with a paste type of flux in the areas to be soldered and then wrap them with the wrapping wire. Coat this assembly with some more paste flux.
A 100 watt soldering iron will not get the assembly hot enough. A small propane torch will work well. If you have a larger household type of torch, don't turn it on full force. A flame about one inch long should work well. Heat the joint with the inner blue cone of the flame. The flux will bubble and start to burn off. When you think the joint is hot enough, remove the flame and apply the solder. Most types of solder will work. We usually use rosin core as that is what we usually have out.
If the joint is hot enough the solder will flow into the joint. If it doesn't flow, the joint is not hot enough. If the joint gets too hot, the flux will completely burn off and you will have to start all over again. If you do not remove the flame the solder will melt before it touches the wire, making it very difficult to get it to flow into the joint.
Done correctly, the joint will cool slightly as the solder flows in. When this happens the solder will stop flowing. Remove the solder and reheat the joint a little. Remove the heat and flow some more solder in. You might need to do this two or three times.
When you have enough solder in the joint, lightly wipe it with a wet rag to remove any excess solder.
I am interested in using a 3-or 4-bladed prop for a more scale appearance. How do I decide what size prop to purchase?
Please be aware that 3-bladed props are less efficient than a 2-bladed prop, so you are going to lose some performance. Additionally, 4-bladed are less efficient than 3. If your model is already marginal on power on a 2-blade, we strongly recommend against a 3-blade prop.
If, however, you have plenty of power and are willing to give up some performance for scale look and sound, then a 3-bladed prop is for you. You will want to start with a prop with either 1" less diameter or 1" less pitch than your 2-blade prop as a rule of thumb. For example, if your engine happily turns a 13x6, try a 12x6 or 13x5 to start with. Then adjust from there as needed.
To go to a 4-bladed prop, decrease an additional inch in either dimension. If your normal prop choice is, for example, a 11x6, you would begin with a 10x5 and work from there to find a 4-bladed prop that best fits your circumstances.
When should I use a 2-stroke engine vs a 4-stroke?
A 4-stroke gives you more torque, more power off the line, better vertical performance, and slower more scale flight speed because it turns larger diameter, lower pitch props. A 2-stroke is generally lighter and more powerful for the same displacement (not always) and goes faster, turning higher pitch lower diameter props.
My servos work backwards on my new model. What's wrong?
There are two possible answers to this question:
1. Moving control A activates the wrong servo. In this case, please unplug all servos from your receiver, check your model's and radio's instructions, and reinstall. Note that some manufacturers use different designations for which slot controls which channel so when in doubt follow your radio's manual.
2. When you move control A the servo goes the wrong direction. For example, moving your rudder stick right causes the rudder to move left. This is an installation or set up problem with your model. If your radio has servo reversing switches or computer radio programming, reverse the direction of that servo. If it does not, you will need to purchase a reversed servo, a servo reversing lead, or change your linkage so the pushrod works from the opposite side of the arm so that the linkage operates properly.
This aircraft has dihedral or polyhedral in the wing. I want the model to be aerobatic. Can I remove this?
We strongly recommend against modifying the designs. Each aircraft is tested extensively and set up based upon a specific design parameter. For example, removing dihedral in the GP CAP 232 will result in the model having a noticable roll reaction when rudder is applied.
My model's engine is not placed dead center on the firewall. Why?
Most aircraft benefit from having right thrust or down thrust built into them. (Note that some models because of their wing configuration require upthrust.) The model's engine is pointed right and or down slightly (a few degrees) to counteract certain aerodynamic forces which occur from the force of the engine and propeller. The engine's position on the firewall is usually shifted just enough so that the spinner backplate will still be centered on the aircraft.
We strongly recommend not changing or removing the thrust angles built into your model, as they are extensively tested and were specifically selected to provide specific flight behavior. For example, removing the up thrust in a GP CAP 232 will result in the model having to carry positive elevator for full throttle flight and the pitch trim setting for full throttle will result in a balloon at other throttle settings.
No matter what throttle setting I have, my tach always reads approximately 3600 RPM. What am I doing wrong?
Your tachometer is very likely reading flourescent lighting. Please note that your tach cannot operate properly in flourescent lighting. Please try using it in natural light.
How should I fuelproof my firewall or fuel tank area?
There are a variety of ways to do this. One way is to fuelproof it with iron-on covering such as Top Flite MonoKote. That is to say, cover the entire firewall (but not the engine compartment) or interior of the tank area, then just use small amounts of thin CA or thinned epoxy to fill in around any openings.
Another way to do so is to paint with fuelproof paint or with thinned epoxy.
I am having difficulty painting on my fiberglass parts. What am I doing wrong? Is there anything special I need to know?
All fiberglass parts are made in a mold which was coated with some kind of mold release, some of which would undoubtedly still be on the surface. This must be fully removed or paint will not stick or will react because of residual mold release. Before painting, one should first clean the surface thoroughly, possibly using a solvent, such as mineral spirits or naptha (lighter fluid). Depending on the type of glass and release agent, the solvent could attack the surface, so a test should first be done in an inconspicuous area. If that doesn't work, then perhaps a light sanding of the area to be painted, followed by a thorough cleaning, may work. If the mold release (possibly silicone, to which nothing sticks) somehow was partially absorbed into the surface, it's going to be difficult to paint without first sanding off the outer layer.
What is a 'retract servo'? How is it different from a standard servo? Should I use it with mechanical or pneumatic retracts?
A retract servo is specifically used for mechanical retracts. It is a non-proportional servo which only moves 180 degrees. That is to say this servo is either "off" (gear up and fully locked) or "on" (gear down and fully locked). No ATV, EPA, or AST adjustments can be made on these servos because they are not proportional. The linkage must be set up properly to allow this servo to operate at its full range and do its job—securing your model's landing gear in a gear-up or gear-down position.
What temperature should I use to apply my covering?
The temperature will depend upon the covering material you are using. Please see your covering material's instructions for guidelines. Please note, for example, clear and transparent MonoKotes have very different temp needs than opagues or flats.
For a chart on proper temperatures for popular coverings, please see:
For further information on working with covering materials, please visit:
My new model calls for the servos to be mounted on the exterior of my aircraft (sticking out of the wing or tail.) Is this okay? Will the fuel and dirt damage my servos?
Most current-generation servos are sealed well enough, so that a small amount of dirt, fuel, and such are not a concern unless you have reason to anticipate dead stick gear up or similar landings, in which case you might damage your servos with ground contact. Otherwise, external exposed servos are very common and easy to service/inspect, and are quite common in today's larger ARFs. However, it is always a good practice to wipe your exposed servos down after each flying session to prevent degradation of the plastic or problems with the output shaft.
How do I apply the decals included in my kit? Do I need to use water? Do I need to protect or seal the edges?
These are pre-adhesive decals. Simply trim around the decal shape with a hobby knife, lift carefully, (be sure not to stick it to your fingers!) and position the decal in the desired location. HINT: round edges rather than sharp points will minimize the chance of catching and peeling the decal back up.
To give your decals—and your covering and seams—the best possible protection you may want to consider covering the entire model in a thin layer of clear coat paint. Be sure to test the clear first to confirm it is compatible with your covering (for example, LustreKote and the paint on Coverite fabric are NOT compatible) and your decals.
I have higher torque servo(s) to put in my scale, aerobatic, or 60+ sized model. Where would you recommend I install it (them).
This will depend upon your specific aircraft, however, here are some general rules of thumb. In most applications where the model will be asked to perform any type of aerobatics, the most powerful servo(s) should be applied to rudder. For non-aerobatic applications, the most powerful, best centering, most reliable servo(s) should always be put on the elevator.
My manual says my model should have washout of x degrees. What is washout and how do I tell if my model has the proper amount?
For a definition of washout, please see our glossary.
You will want to utilize an incidence meter to determine the washout of the wing of your model. To do so, set the incidence meter on the root of the wing, and read the angle of attack of the root. Write this down. Now measure the angle at the tip of the wing and write this down. The washout in your wing is the difference between these two measurements (root - tip = washout).
Note that washout means the leading edge of the wing tip is lower than the leading edge of the wing root. If it is the opposite, the model has washin, which is desirable in certain types of aerobatic models for extreme performance, but not in most other models due to decreased stability.
To install washout into a wing:
I am building a small model. Should I leave the antenna hanging out the back of the plane or wrap/fold/cut it?
Never shorten your antenna by cutting down its physical length or by folding it back upon itself. Always allow the antenna to extend its full length, even if it means having a 'tail' hanging out the back of your model. You might also consider running it out the wingtip rather than down the fuselage.
Why does my kit have thin sheeting in it? Why don't you use heavier sheeting?
The decision to use the lightest possible sheeting is an intentional one. Current generation aerobatic and even military scale models are now designed to be as acrobatically capable or as easy to fly as possible within its size and other restraints. You would likely be quite surprised as to the difference a 1/32" change in sheeting (remember you're adding at least 1/2 again the sheeting weight) to the model's performance, and in particular to roll performance and minimizing tip stalling tendencies. The more weight out toward the model's wing tips the more roll inertia the model displays, causing it to oversnap, to be harder to start and stop spins, etc.
These models are intentionally designed to be capable of so much more than 'acceptable sport flying'. These models are designed to be capable of clean, gentle, dependable, smooth flying at wider speed envelopes and orientations than models of even 5 years ago.
Fifteen years ago models were designed knowing they would probably crash, because our radio systems would often cause that of no fault of the user whatsoever. Now that this is so much less of a concern, we are now far more focused on the capabilities of the model.
If you handle the model's wing at all times by leading/trailing edge and spars you will find you have no trouble with the sheeting (assuming it is not bad wood). Much larger aircraft than this are sheeted with 1/16 and survive very successfully; they simply require a slightly gentler handling along the way.
My engine is overheating or running hotter than I would like. How can I get it better cooling?
Most people make the mistake of thinking more is better when it comes to the air INLET at the front of the cowl. This is a common error and while it seems logical the reverse is actually true. This can be confusing. It can really seem backward, as air opening is one place where in some cases less is better. Regarding cooling inside a cowl, you must force air over the engine, otherwise it will escape around the engine (taking the path of least resistance), creating a stale pocket of air over the engine which never gets cool air and so the engine overheats. A properly shaped cowl or a baffle forces the air over the engine area, not giving it an easy escape route otherwise.
To properly cool your engine you need more OUTLET not more inlet. You want at least 2:1, preferably 3:1 air out to air in otherwise it makes a 'dam' and the air can't come into the cowl because it has no where to go OUT of the cowl. If your engine is not cooling properly, try blocking off the other air inlet or opening the belly of the cowl further to better cool your engine.
Also, you may consider creating a baffle so that only 1/4" all the way around your engine is open to allow fresh air in, to properly force cooling to the engine. The air is forced through kind of like a velocity stack, which because its so narrow at the bottom it increases the air pressure coming through. This does the same thing. All that air hits the baffle and MUST go somewhere....so it goes through the much smaller volume opening with much more pressure. See the instruction manual for the Top Flite Corsair (pages 35, 40) for an example of making a baffle to properly cool your engine.
Can I use a gyro in an airplane? When is it a good idea?
Aircraft gyros are fairly new, and some people consider them a bad idea while other people consider gyros to be the perfect tool for just about everything. Let's take a look at some of the common uses along with the pluses and minuses associated.
Will they help me learn to torque roll?
The most common request is how to set up gyros for learning to torque roll. (Don't know what a torque roll is? Please consider purchasing GPMZ0220, A Look at Aerobatics.)
One modeler describes torque rolling as the equivalent of balancing two plates on top of broom sticks, with your eyes closed, while bouncing a top a large rubber ball. So, if it doesn't come quickly and easily, don't fret! It takes a lot of time and practice. And don't be upset if a gyro doesn't suddenly make your model torque roll alone—it won't. But it will help a little to a lot, if everything is set up properly.
Using gyros in an aircraft to aid in torque rolling has its advantages and its drawbacks. Gyros can assist a modeler in learning to torque roll because it will correct SOME to ALL (depending on the type, quality and settings of the gyro) of the yaw and pitch movements caused by the torque and instability of the aircraft in this precarious position; however, it will also be countering corrections made by the modeler so the modeler has to think and move even faster and give even more input to make corrections against the gyro and the aircraft.
Basically, a torque roll is an extremely unnatural action for an aircraft which requires incredible pilot skill to maintain and complete. The model is being suspended solely by the power of the engine/thrust from the prop, with just the right amount of throttle being given to keep the model from climbing or tail sliding. The torque of the engine will pull the model around to the left, with no amount of aileron input in the world being able to stop the rotation UNLESS the model has ailerons extending all the way in against the fuselage or has ailevators functioning as ailerons. This torque, and gravity, are also twisting the model on both the yaw and pitch axes, which requires extreme skill by the modeler to correct.
If you wish to use gyros to help ease the difficulty of this complex maneuver, you will want to install one gyro each for the elevator and rudder surfaces. Note that if your model uses twin elevator servos which are plugged into separate ports you will need a product like the Hobbico Aircraft Gyro (HCAM4010) or the Futaba GYA351 (FUTM0817) which supports 2-channel input and output for a single axis.
We used to recommend AGAINST heading hold gyro settings for torque rolling, as the gyros sometimes seemed to lag behind, and improperly correct as the model got farther and farther into the torque roll. However, the new Futaba GYA350 and 351 gyros have changed our minds! These specialty gyros specifically for aircraft use perform superbly in AVCS (heading hold) mode in torque rolls and similar circumstances. (Always remember to switch out of AVCS mode for 'normal' flying.)
It is important to remember that, while heading holds are the only gyros which will truly return the model to its initial orientation (other gyros just correct for movement, but not necessarily back to the starting point), there are MANY situations in which you and your model can be unintentionally in danger when the heading hold returns the model to a position you did not intend.
Please remember that normal gyros will not 'do it for you'. They are not a 'missile lock' or 'heading lock' and do not fixate on a position in the sky and maintain it. They simply dampen unwanted (and wanted!) motion, so they will not make torque rolling suddenly easy. But depending on your skill, your model, and your understanding of the dynamics, they can be a good training aid for torque rolling.
How about other maneuvers?
Gyros ARE a great aid in many other aerobatic maneuvers. They are amazingly beneficial, for example, when used during maneuvers such as snaps, tumbles, and stall turns. In some cases the heading hold or AVCS option will be beneficial, and in others not. Always remember....if you try to change your yaw line without moving the rudder servo and have a heading hold gyro on the rudder (for example, doing a banked turn with just aileron and elevator), the heading lock gyro will immediately return the model to the initial direction of travel! Therefore, it is best to leave the gyro in standard mode, not heading lock mode, except in specific circumstances where you want the 'dead on tracking' of heading lock mode.
Lastly, gyros are extremely popular on the rudder of scale aircraft, especially complex nostalgic aircraft which are notorious for difficult ground handling. In this case many modelers DO use a heading lock gyro or AVCS (heading hold) mode in a switchable gyro, but then turn off the heading lock feature the moment the model breaks ground. This way the model will literally track perfectly straight with no rudder input from the pilot whatsoever.
What's the difference between a marine engine and an aircraft engine?
There are several differences between marine engines and airplane engines. First, marine engines are usually water-cooled (special head). Second, marine engines require a special "flywheel" and "coupler" to connect and start the engine. Third, due to the high performance nature, most boat motors are designed for this application and usually have ball-bearings.
HOW TO MAKE "SOFT WEIGHTS"
Weights are needed for a variety of purposes during the model building process, especially when setting wing washout or if you need an extra pair of hands. We made some 2 and 3 pound "soft weights" for use in our shop as follows:
A. Obtain four smallish, but sturdy plastic bags (freezer bags work well), four old tube socks (preferably laundered), and 10 pounds of buckshot, available at sporting goods or gun stores. Sand can also be used, but the weights become pretty bulky.
B. Use a scale to measure out two 2Lb bags and two 3Lb bags of shot (or sand). Seal the bags with masking tape, without compressing the contents. Soft weights work best if they are floppy like bean-bags.
HOW TO MAKE A BALSA SKIN
REPAIRING SURFACE "DINGS"
Many surface blemishes on a framed model are caused by bumps and balsa chips on the work surface. This type of ding is best repaired by applying a drop or two of window cleaner or tap water to the blemish, then running hot a sealing iron over the spot to expand the wood fibers. After the surface has dried sand the expanded area smooth.
Final sanding - Fill any scuffs, dings, and the forward end of the pushrod tube exit slots with balsa filler (Hobbico HobbyLite #HCAR3401 recommended). After the filler has hardened, cut and sand the pushrod tubes flush with the fuselage sides, then sand the entire structure with progressively finer grades of sandpaper, ending with 320-grit. When you think the job looks good, sand some more to make it better. You'll be glad you did.
Fuelproofing - Fuelproofing may be done either before or after covering. Fuelproof the engine and fuel compartments, by painting them with fuelproof paint or 30-minute epoxy thinned with about 25% Rubbing Alcohol. Pay special attention to the firewall. Prevent paint or epoxy from clogging the blind nuts by first packing the holes with petroleum jelly applied with a toothpick. Be sure to clean off any "external" petroleum jelly "messes" with rubbing alcohol before fuelproofing.
Keeping Wheels in Place on Axle and Model Tracking Straight
Install the wheels on the landing gear using two wheel collars per axle. Grind or file a flat spot at the point of setscrew contact for each of the outer collars. This provides a better area for the setscrew to bite and helps keep the wheels in place.
NOSE GEAR FLAT SPOT
Proper Servo Mounting:
The proper way to mount a servo is as follows:
Important things to check in Pre-Flight:
No list is all inclusive or fits all models, but here's a good starting point:
Important Engine Safety Precautions
No list is all inclusive, but here are some basics to watch for:
NOTE: Failure to follow these safety precautions may result in severe injury to yourself and others.
Quantity/position of rubber bands to secure my model's wing?
If you are using rubber bands to attach your wing, the rule of thumb is to use two #64 rubber bands per pound of model weight. If your model tipped the scales at 7 pounds, you need 14 rubber bands. It doesn't matter too much how many you run straight across the wing or how many are criss-crossed, so long as the last two are criss-crossed. This trick stops the other bands from popping off. Do not use oily rubber bands for more than a few flying sessions. Check each rubber band before using it, watch out for cracks. Rubber bands can be conditioned by storing the oily ones in a zip-top storage bag partially filled with talcum powder or corn starch. Both products will absorb the oil.
Basics of Flying—IncludingTaxi/Take-Off/Landing
Of course, no brief written guide can replace an instructor in safely teaching you to fly. This guideline is intended only to help you understand the steps to come and practice in simulation when your instructor is not available.
Start the engine and set the throttle trim for a slow, steady idle. Have your instructor or a helper hold the plane while you work the controls. Upon release advance the throttle slightly to start rolling, then back-off the power to prevent going too fast and possibly taking off. Stand behind the plane as it taxies away from you and note the direction it turns as you move the rudder control. One thing to keep in mind with R/C models (whether it be cars, boats, or planes) is that the steering controls may seem to "reverse" when the model is moving toward you. For example, if you are flying toward yourself, and you give a right control input (ailerons or rudder), the model will move off to your left. The fact of the matter is of course, that the controls are not reversed and the aircraft did actually enter a right turn. The plane does move off to your left from your vantage point, but if you imagined yourself in the cockpit you would realize the plane turned to the right as commanded. All it takes is a little practice to maintain proper orientation of your aircraft ( it sometimes helps to face the direction of movement and look over your shoulder), but that's why we recommend finding an instructor. When you feel comfortable, advance the throttle a little while standing behind the plane to get the feel of a takeoff roll, but pull back on the power before the model lifts off. Try this several times, adding a little more power each time. If the plane starts to veer off, immediately cut the power to prevent a mishap. Although many R/C pilots have taught themselves to fly, we strongly recommend that you find an instructor to help get you started. Although trainers offer the greatest opportunity of success for the self-taught, there is a high probability that you will crash your airplane on the first flight. Protect your investment of time and money—obtain the assistance of an experienced R/C pilot.
Your first flights should be made in little or no wind. If you have dual rates on your transmitter, set the switches to "low rate" for takeoff. Taxi into position, pointing directly into the wind. Although trainer models have good low speed characteristics, you should always build up as much speed as your runway will permit before lifting off, as this will give you a safety margin in case of a "flame-out." Advance the throttle smoothly to the wide open setting. When the plane has sufficient flying speed (you won't know until you try), lift off by smoothly applying a little up elevator (don't "jerk" it off to a steep climb!), and climb out gradually, trying to keep it straight and the wings level. The model should climb at a 20 or 30 degree angle under full throttle. Climb to about 100 feet before starting a VERY gentle turn by moving the aileron stick. Apply a little more back pressure on the elevator stick as the plane turns. Stop the turn by moving the aileron stick in the opposite direction until the wings are level then return the stick to the neutral position. Pull the power back to 1/3 throttle.
We recommend that you take it easy with your trainer for the first several flights and gradually "get acquainted" with the plane as your engine becomes fully broken-in. Most trainers are designed to fly level with neutral elevator trim at approximately 1/4 to 1/3 throttle—this is the best speed for learning to fly. On later flights, if you want the model to maintain level flight at full throttle, you will need to give it a little down trim.
Your first flights should consist of mostly straight and level flight with gentle turns to keep the model over the field. These flights will give you practice at coordinating your control inputs and maintaining the proper orientation of the airplane. As mentioned earlier, turns are accomplished by banking the aircraft with the ailerons (rudder will accomplish this on a 3-channel airplane) then gently adding some back stick (up elevator). Enough back stick should be held in to keep the aircraft at a constant altitude. To stop turning, apply opposite aileron (or rudder) to level the wings, then release the sticks. There is a memory aid that may help keep you out of trouble when the plane is flying toward you—"put the stick under the low wing." In other words, move the stick in the direction of the low wing to raise that wing. When you are comfortable flying the aircraft, you can practice using the rudder along with the ailerons to 'coordinate' the turns—usually, a small amount of rudder applied in the direction of the turn will keep the tail following the same track as the nose.
The most common mistake when learning to fly is "over control." Think of pressure instead of large movements of the control sticks. Remember nearly all trainers will recover from almost any over control situation within 50 - 100 feet if you simply let go of the sticks.
Add and practice one maneuver at a time, learning how your plane behaves in each one. For ultra-smooth flying and normal maneuvers, we recommend using the "low rate" settings as listed in your manual. High rate control throws will give your model enough control for loops, barrel rolls, and many other basic aerobatic maneuvers.
After you have several flights on your trainer, its time to reward yourself with your first aerobatic maneuver—a loop. Climb to a safe altitude and turn into the wind. Apply full throttle, level the wings, then slowly pull back on the elevator stick to about 1/2 to 3/4 up elevator (depending on your throws), and hold this control input. After you go over the top and start down the back side of the loop, pull the throttle back to about half, this will keep the stresses on the airplane low and the airspeed relatively constant. Keep holding "up" elevator until the plane is level, then slowly release the sticks. You're done! It's really that easy!
When it's time to land, fly a normal landing pattern and approach as follows: Reduce the power to about 1/4 and fly a downwind leg far enough out from the runway to allow you to make a gentle 180 degree turn. As you make the turn into the wind for your final approach, pull the throttle back to idle. The PT-60 has a lot of lift so you will need a slow, reliable idle in order to achieve a nice slow landing. Allow the plane to keep descending on a gradual glide slope until you are about 3 feet off the runway. Gradually apply a little up elevator to flare for landing. You should apply just enough up elevator to hold the plane just off the runway while the excess speed bleeds off. The trainer should settle onto the runway for a slow, slightly nose-high landing.
How does motor choice affect my model's performance?
In electric motors, an increase in winds means an increase in top end speed. A decrease in winds means an increase in torque, or acceleration. Conversely, more turns means more torque/acceleration, while less turns means more top end speed.
Pinions and spur gears work the same as turns—more teeth, more torque, less teeth, less torque but more speed.
My 3D aerobatic plane tends to hang with the tail tucked under the belly or pushed away from the belly. I can't get it to hang straight vertical. What am I doing wrong?
Don't worry, you're not doing anything wrong. This is a result of the vertical balance point and thrust line of the model and is perfectly normal. Different aircraft will 'hang', torque roll, and harrier at different angles of attack because of these forces. DO NOT change the model's thrust line (assuming it is accurate for straight and level flight) as this will not resolve the problem.
Model snaps, tip stalls, or loops off to one side. What can I do?
There are a variety of causes of this behavior.
How long can I store unopened fuel? how about opened fuel?
How do I check incidence on a park flier?
The Great Planes AccuPoint Laser Incidence Meter and the Robart incidence meter are not well suited for measuring incidence angles on small, flimsey airplanes such as park flyers and indoor flyers. The units are simply too bulky and too heavy.
One accurate way of measuring these angles is as follows:
It's not an easy way to do it, but it is mathematically accurate.
My switch stopped working, and when I checked it, I found the black wire all corroded. The copper part looked dark and was brittle. What happened?
This is a case of what's been called "Black Wire Corrosion". Over time, the negative lead from the battery pack, through the switch harness, to the receiver will corrode until the copper wire becomes dark, almost black, and brittle. It no longer has the bright "coppery" look, and is no longer flexible.
The cause is storage of the system in a damp environment with the battery installed. The effect of the wire being connected to the battery pack, and the environmental moisture, will cause an electrical effect to promote corrosion of the wire. The corrosion usually starts at the battery pack and works its way towards the switch harness.
A "damp" environment does not necessarily mean that it's particularly humid. Storage in a garage or shed provides enough humidity to allow the corrosion to happen. The wet that gets brought into a garage from your car is enough. It will happen faster if the battery pack is not maintained and allowed to go flat. Keep the battery charged and cycle it regularly to prevent or slow down the corrosion.
The net result of black wire corrosion is to make the battery lead act like a resistor, which will prevent proper current flow from the battery pack to the receiver and servos. In some cases, the resistance can be high enough that during aerobatics, with all servos moving, the voltage at the receiver can drop enough to cause the receiver to quit. The model crashes as a result.
What can make this baffling is the fact that the R/C system may operate normally when tested. That's because the tests don't involve high loads upon the servos, so the voltage drop caused by the resistance of the corroded wire isn't enough to cause the receiver to quit.
Transmitter batteries can also be affected, but usually not as much because transmitters are usually stored in a friendlier environment. They still need to be checked periodically, though. When the corrosion gets bad enough, the transmitter will just not turn on. It's not likely that the transmitter will fail during a flight.
The effects on the corrosion would also be seen on the transmitter's power meter as low output. The battery pack gets blamed, gets replaced, and the problem goes away. That's because a new battery pack comes with new wires. Corrosion may never even be suspected or found in these cases.
There is no cure once black wire corrosion starts. You can only replace the wires. Prevention requires that your equipment be stored in a clean, dry environment, and maintain your batteries. Store them fully-charged and cycle them regularly. If you can't do that, then at least remove the batteries from your models, and store them, along with your transmitters, inside, where the temperature and humidity are fairly stable, compared to a garage or shed.
Is it ok to let my antenna touch the pushrods, servo leads, etc?
No. It is important not to let the antenna touch the pushrods, servo leads, etc. It is particularly important not to allow the antenna to make contact with anything metallic in the aircraft. We recommend running the antenna through its own pushrods tube to isolate it safely.
My airplane's electric motor runs in the wrong direction. What do I do?
First off, it's not the speed control. Model airplane speed controls have only forward, off, and sometimes propeller brake. The problem is elsewhere.
There are two things to check. First off, make sure your motor is wired correctly. Sometimes the "+" and "-" symbols on the motor are not correct for your installation, and you really have your motor wired backwards. You can easily check this with a tach. If your motor turns more RPM in one direction than the other, the higher-RPM direction is the correct direction.
If your motor is wired correctly, but the propeller still turns in the wrong direction, you may have to change how you're gearing the motor. This usually happens when a gearbox and motor are put together by the modeler, and the motor was not purchased specifically for the gearbox.
I did not find the answer to my question here. How do I get further assistance?