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Sunday, August 3, 2008

How to Choose the Right Glow Plug

The "right" glow plug for your engine is the one that gives you the best performance. And you can choose the right plug for any situation, just by following the guidelines below.

1. Engine Type - Know what type of engine you have. Is it a standard - or a turbo?

Standard engines (engines with a 1-piece head) are most common. Standard plugs are easily available, inexpensive and fit almost all standard engines. Standard plugs are installed with a washer, which creates a compression seal with the head.

Many new engines are turbo engines, which feature a special 2-piece turbo head. The biggest benefit of turbo plugs is superior performance. Unlike standard plugs, turbo plugs (identified by a "P" in the description) feature a tapered "seat" that matches perfectly with the head that will creates a superior compression seal and with it, maximum efficiency and power. Turbo plugs are the choice for racers who want and need top performance.

Caution : You should never install a turbo plug in a standard engine or vice versa. Doing so may cause serious (and expensive!) damage.

2. Displacement - What size is your engine? Is it .12? .15? .21?

Size matters to glow plugs. Big engines have more mass and retain heat better. Smaller, lighter engines don't, and need the help a hotter plug can offer. Therefore, the smaller the engine, the hotter the plug.

3. Fuel Nitromethane Content - What's the nitro percentage in your fuel?

High-nitro fuels produce more power than low-nitro fuels, but also produce more heat. Hence, the higher the nitro content, the colder the plug.

4. Temperature

Smart modelers tend to keep a variety of glow plugs on hand. Simply because the "right" plug for your engine can change with the temperature. To achieve top performance, your choice of plug needs to change, too. Also, the hotter the day, use a colder plug.

5. Other Considerations - A few other things you should know.

Hot plugs promote better idling and acceleration. If your engine runs rough or accelerates sluggishly, a hotter plug will help.

Cold plugs produce more power and may improve performance if your engine runs hot. The downside is rougher idling and more difficulty in tuning.

Where you run also plays a part. If the track/course has a lot of twists and turns, a hot plug is fine. If the track/course has long straights where you'll reach maximum rpm, a colder plug is best.

Fuel-air mix not only affects how your engine performs; it can also have an impact on how long your plug lasts. If you run rich, it means that you're using more fuel than necessary for top performance. Modelers are often advised to run rich during engine break-in, because it helps cool the engine. However, running too rich can also cause an engine to "bog down" or quit entirely. In addition, it also means that the glow element is being exposed to more contaminants than necessary, which shortens plug life.

Running lean means that you're using less fuel. "Leaning down" an engine has a positive effect on performance. However, care is needed here, because over-leaning an engine can harm it, by raising operating temperatures, "burn up" a plug before its time.

6. Finally

Choosing the right glow plug not only improves performance, but can also extend the life of your engine and the glow plug itself. Here are a few more tips for you.

  • Buy quality plugs. You're protecting your investment.
  • Store plugs where it's dry. Moisture can ruin them.
  • Use the right glow plug. Follow the guidelines above.
  • Follow proper break-in procedures.
  • Tune your engine carefully. Running too lean will make your engine "blow" plugs more often. Proper tuning helps extend plug life.
  • Never touch the filament of a glow plug. Doing so can break the filament and ruin a plug.
  • Don't overtighten your plug. Tighten it until just tight.
  • Be sure to shim your engine correctly. A plug that's too close to the piston can cause pre-detonation, which will quickly damage a glow plug.
  • Use only a glow starter or 1.5V battery to heat your plug. Otherwise, your plug may burn out ahead of its time.
  • Don't be afraid to ask for help. Experienced modelers have already "been there and done that." Their experience can save you time and money - and most are glad to help.

How a Glow Plug Works?

Spark plugs in gasoline engines start ignition with a spark. In nitro engines, glow plugs cause ignition with heat.

Heat is created initially by connecting a glow starter or 1.5V battery to the plug. Once the plug comes up to heat, the battery is disconnected and the heat retained by the combustion chamber will keep the engine running. Engine timing is automatic and controlled by engine RPM. Running at higher RPM makes the plug hotter and "fire" the fuel-air mix sooner. At lower RPM, the filament cools and the plug fires less frequently.

Saturday, May 3, 2008

Removing Unwanted Epoxy Blob / Stain from your Model?

How many times have you got that unwanted and excess epoxy after joining two joints together and leaving behind the ugly residue?

or

How many times have you got epoxied fingerprint all over your beloved models?

or

How many time have you tried to removed some dried out epoxy but failed?

Well here's the solution! Denatured Alcohol!

Denatured Alcohol is a gentle, multi-purpose solvent, which is essential for thinning shellac and cleaning brushes. It evaporates quickly, making it an excellent glass cleaner. Also works great for cleaning metal, water rings, color-safe fabrics, and it is even used as a hot, clean-burning fuel for marine stoves. Best of all it removes epoxy! Even for long dried out epoxy, just 'soaked' it using Denatured Alcohol and clean / scrapped it off after that.

So what is this wonderful solvent? A quick definition and explanation of Denatured Alcohol here in the Wiki.

http://en.wikipedia.org/wiki/Methylated_spirits

Sunday, March 23, 2008

Wing Fence

The term “wing fence” may also be identified by the terms “boundary layer fence,” “potential fence,” or simply “fence.”

Wing fences have been used on swept wing aircraft for fifty years. The MiG-15, one of the earliest examples of their use, incorporated two fences on each wing. The F-86 used them as well. Fences can also be seen on more recent production aircraft like the Fiat G91 and the BAE Hawk and Harrier.

Despite their use on aircraft flying at supersonic and near supersonic speeds, wing fences are also of use on low speed swept wing aircraft such as man carrying sailplanes and RC models. The Akaflieg Braunschweig SB-13 and a rendition of Hans-Jürgen Unverferth’s CO8 by Glyn Fonteneau and Dave Camp serve as examples within those realms. Wing fences have both an interesting history and an interesting effect.

A wing fence is nothing more than a flat plate which is attached perpendicular to the wing and in line with the free stream air flow. Wolfgang Liebe is credited as being the inventor of the device, for which he received a German patent in 1938, during his work on the Messerschmitt Bf 109B. The Messerschmitt Bf 109B had a rather peculiar stall.

The stall initiated at the wing root, and a cross span flow very near the leading edge then travelled outward toward the wing tip at high speed. The result of this aerodynamic behavior was that the entire wing stalled at essentially the same time, a very dangerous characteristic.

Installation of a wing fence prevented the cross span flow, thus eliminating the stall problem. That a solid plate in the path of cross span flow close to the wing surface would obstruct the flow, as was seen on the Bf 109B, may seem obvious.

In actuality, however, the mechanism of operation was more covert in that the beneficial effect was provided by the initiation of a sideslip and the resulting vortex generated by the fence. Wing fences on swept wings have been found to be very beneficial to inhibiting the nasty stall behaviors which result from severe angles of sweep, but their operation in this environment is entirely different than on a straight wing such as the Bf 109B.

As we mentioned in the opening parenthetical paragraph, wing fences have had other terminologies applied to them. “Boundary layer fence” is the most common, so let’s take a critical look at that nomenclature for a moment.

The boundary layer is that region next to the surface of a solid body where there is an appreciable loss of total pressure. That is, the velocity is a fraction of the free stream flow. The boundary layer thickness is usually defined as the distance normal to the surface in which the velocity rises to 99% of that of the main flow. The boundary layer is in reality not very thick, usually a matter of a few millimeters, even on full size aircraft.

With the above definition in mind :

If a wing fence is constructed to be the same height as the boundary layer thickness, it is not effective. In fact, fences must be quite high to have any effect at all.

The boundary layer gets thicker toward the trailing edge of the wing, so if fence height were based on the boundary layer thickness the fence would be highest at the trailing edge of the wing. Yet extending the length of a fence much beyond 50% chord does not increase its effectiveness in the slightest.

Wing fences are generally more effective when they wrap around the leading edge.

The term “boundary layer fence” is, as illustrated by the above points, a misnomer. Wing fences do not affect the boundary layer directly, but rather do so indirectly by having an impact on the potential flow, the flow in which the vorticity is zero.

The term “potential fence” is derived from the action of the fence on the potential flow. Wing fences on swept wings work in a very complex way, and their action is not completely understood, but we’ll attempt to make the fundamental concepts easier to understand.

Begin by thinking of a swept wing panel mounted in a wind tunnel and its associated lift distribution, as shown in Figure 1. Note that if the right wall is removed we have a right wing panel for a swept back wing; if the left wall is removed we have the left wing panel of a swept forward wing.

From a slightly different perspective, by removing the walls and attaching a “mirror” wing panel to either the left or right end of the existing wing, we have a complete wing, swept either backward or forward, and an associated lift distribution as depicted in Figure 2.

We can consider a wing fence to be aerodynamically equivalent to a tunnel wall. This effect is demonstrated in a more comprehensive way in Figure 3.

Installing a wing fence changes the lift distribution on a swept back wing as depicted in Figure 4.

Note that on the inside of the fence the cl is higher while on the outside of the fence the cl is lower. This shifting of the load to the inside of the fence is very beneficial to stall behavior. The clmax should be located in the area approximately 40% of the semi-span from the wing root. At a high angle of attack, this should be the area of the wing which stalls, leaving the wing root and the wing tip to continue providing lift and a slight pitch down moment.

When high angles of attack lead to separated flow, the boundary layer is directly involved at a fundamental level. Corrective measures must influence the boundary layer in such a way that flow separation is limited or controlled to some extent. As previously said, wing fences do not directly influence the boundary layer.

Rather, they influence the potential flow which in turn effects the boundary layer. In general terms, the cl load on the wing tips is reduced, the boundary layer is maintained in such a way that separation is inhibited, and the stall behavior is made more benign. Rarely do wing fences extend farther than 1/3 of the wing chord. The forward third of the chord is the area of greatest lift. It is also the area where the sweep effect and the “mirror” principle, described in Figures 1 through 4, are most effective.

For use on RC sailplanes, wing fences are usually constructed using a profile similar to those shown in Figure 5 and are fabricated of stiff cardstock or plastic. They can be conveniently attached with tape for easy removal, replacement, and/or experimentation. The most common location for wing fences is between 40% and 60% of the wing span.

A location directly in front of the inner edge of the aileron or elevon has shown to be very effective at controlling adverse stall behaviors and maintaining control surface effectiveness at high angles of attack. Installing two fences on each wing panel, at 1/3 and 2/3 of the semi-span, has been found to be effective on high aspect ratio wings with steep sweep angles.

Wing fences are sometimes not easily seen. Most airliners have their engines mounted below the wing on pylons. The pylon itself serves as a fence for the lower surface, and the leading edge pylon fairing often comes over the leading edge, serving as a fence for the upper surface.

Controlling air flow to improve swept wing flight characteristics can be accomplished through a number of means - wing slots (as described in our August 1994 column), leading edge slats, and the “saw tooth” leading edge to name just a few. Wing fences are attractive, however, because they can be fabricated quickly, attached readily, and modified easily without affecting the main airframe in any way.

So far as cost and ability to experiment, they are the best suited solution.


KF Airfoil Vortex



How to Convert a 2 Blade to a 3 or 4 Blade Propeller?

The conversion for a 3 and 4 bladed propeller is a simple tasked if you know what 2 bladed propeller you use on a given Engine or Motor. For example, on a three bladed propeller you would drop the diameter and keep the pitch. On a four bladed, you would drop the diameter and the pitch. For instance if you had a two bladed 24-10 propeller and you wanted a three bladed you would use a 22-10 and so on.

The performance on a 2 bladed verses a 3 bladed propeller is very little. A 3 or 4 bladed propeller will give you more thrust, and you will sacrifice a little speed. The big advantage to using a multi blade is that you have more ground clearance less noise factor.

3 & 4 BLADED CONVERSION CHART

Two Bladed Three Bladed Four Bladed
10-6 9-6
11-8 10-8 10-6
12-8 11-8 11-6
12-10 11-10 11-8
13-10 12-10 12-8
14-10 13-10 13-8
14-8 13-8 13-6
15-8 14-8 14-6
15-10 14-10 14-8
16-10 15-10 15-8
18-10 16-10 16-8
20-10 18-10 18-8
22-10 20-10 20-8

Tuesday, February 12, 2008

Thermal Soaring

Thermal soaring is one of the most intriguing of all aspects. It can be hard for the average person to understand how a plane can fly for hours and gain altitude without a motor!

It takes a lot of concentration to thermal soar effectively. A sailplane can fly along the edge of a thermal and unless the pilot is carefully watching the model he may not realize the opportunity to gain some altitude. Because most thermals are relatively small (a couple hundred feet in diameter or less at 400' altitude) compared to the rest of the sky, the sailplanes will rarely fly directly into the thermal and start rising.Generally, the sailplane will fly into the edge or near a thermal and the effects the thermal has on the plane may be almost unnoticeable. As the sailplane approaches a thermal, the wing tip that reaches the rising air first will be lifted before the opposite wing tip. This causes the plane to “bank” and turn away from where we would like the plane to go.

When you are thermal soaring, try to fly as smoothly and straight as possible. Trim the plane to fly in a straight line and only touch the controls when you have to. Watch the sailplane carefully and it will tell you what it is encountering.When the sailplane flies directly into a thermal it will either start rising or stop sinking. Either case is reason enough to start circling (especially in a contest where every second counts). Fly straight ahead until you feel like you are in the strongest lift, fly a couple of seconds farther (so your circle will be centered in the strongest lift) and then start circling in a fairly tight but smooth turn. When the sailplane is low the turns have to be tighter to stay in the strongest lift. As the plane gains altitude, the turns can be larger and flatter. The flatter the turn, the more efficient the plane is flying, but don’t be afraid to really “crank” it into a steep bank when you are low. If you see the plane falling off on one side of the turn, move your circle over into the stronger lift. Thermals move along with the wind so as you circle you will be swept along with it. Be careful when thermaling, that you don’t get so far downwind you can’t make it back to the field to land. If the sailplane is flying along straight and all of a sudden turns, let the plane continue to bank (you may have to give it some rudder to keep it banking) until it has turned 270°(3/4 of a full circle). Straighten out the bank and fly into whatever turned the plane. If you encounter lift, and you won’t every time, start circling just as you did when flying directly into a thermal.

Thermals are generated all day long, but the strongest thermals are produced when the sun is directly overhead. 10:00 am – 2:00 pm seems to be the best time to get those“killer” thermals. Some of these thermals can be very large and you may find it hard to get out of them. If you find yourself getting too high, don’t dive the plane to get out of the lift. Sailplanes are very efficient aircraft and they will build up a lot of speed and could “blow up” in the rough air of a thermal. The easiest way to lose altitude is to apply full rudder and full up elevator. This will put the plane into a tight spin that will not over stress the air frame but it will enable it to lose altitude very quickly. This is especially helpful if the sailplane gets sucked into a cloud or it gets too high to see.The twirling action will give the sun a better chance off lashing off of the wing and catching your attention. When you are high enough and want to leave the thermal, add a little down trim to pick up some speed and fly 90 degrees to the direction of the wind. If you are not real high and want to find another thermal, you may want to look upwind of the last thermal. The same source that generated this thermal is probably producing another. Just watch out for “sink” which is often found behind and between thermals.

As you might expect, with all this air rising, there is also air sinking. This air is the sailplane pilot’s nightmare that can really make soaring challenging. “Sink” is usually not as strong as the thermals in the same area, but it can be very strong. Down drafts of many hundreds of feet per minute are common on a good soaring day. These down drafts can make a sailplane look like it is falling out of the air. Because of this, it is important that you do not let the sailplane get too far downwind.

When encountering sink, immediately turn and fly 90 degrees to the direction of the wind (towards you if possible). Apply a little “down elevator” and pick up some speed to get out of the sink as fast as possible. Every second you stay in the sink is precious altitude lost.

Facts About Thermal

Thermals are a natural phenomenon that happen outside, by the millions, every single day of the year. Thermals are responsible for many things including forming several types of clouds, creating breezes, and distributing plant seeds and pollen. If you have ever seen a dust devil (which is nothing more than a thermal that has picked up some dust), you have seen a thermal in action. Their swirling action is very similar to that of a tornado but of course much gentler. Most thermals have updrafts rising in the 200 – 700 feet per minute range but they have been known to produce updrafts of over 5,000 feet per minute (that’s over 50 miles/hour straight up!) These strong thermals can rip a plane apart or carry the plane out of sight before the pilot can get out of the updraft.

Thermals are formed by the uneven heating of the earth and buildings, etc. by the sun. The darker colored surfaces absorb heat faster than the lighter colors, which reflect a great deal of the sun’s energy back into space. These darker areas (plowed fields, asphalt parking lots, tar roofs, etc.) get warmer than the lighter areas lakes, grassy fields, forests, etc.). This causes the air above the darker areas to be warmer than the air over the lighter areas and the more buoyant warm air rises as the cooler, denser air forces its way underneath the warmer air. As this warm air is forced upward, it contacts the cooler air of the higher altitudes. This larger temperature difference makes the thermal rise quicker. The thermal is gradually cooled by the surrounding cooler air and its strength diminishes. Eventually the thermal stops rising and any moisture contained in the once warm air condenses and forms a puffy cumulus cloud. These clouds, which mark the tops of thermals, are usually between 2000 and 5000 feet high.

Wednesday, February 6, 2008

A Beginners Guide to RC Soaring

Sailplane or Glider?

A glider is a ship you launch to good height that gently floats back to earth. A sailplane, on the other hand, is a ship you launch to good height and it goes on up from there!

Which one you experience largely depends on whether you have taken the time to set that new lead sled up correctly. Let’s start in the workshop.

You’ve just finished building your latest sailplane masterpiece and have installed your radio gear. All control surfaces seem to be working, your battery is charged and you’re ready for the field, right?

Wrong!

There are some subtle and important steps you need to take to insure optimum performance. First of all, did you weigh your wings separately? Lateral balance not only makes your plane fly straight, it helps it perform better. Add small amounts of lead to make both wings weigh the same.

Your stabilizer should be parallel to wing leading edge and equidistant from stab tip to wingtip. Use your eyeball for the first part and a string to measure the last part. Line everything up first, then glue. Have you set your control surface throws correctly? Look at the manufacturers recommended throws.


Buy a gage and set these up--adjusting holes on the control horn or servo arm or with travel adjust on computer radios--so you don’t get more throw than you need. More throw means you’re more likely to over-control, with subsequent loss of performance and possibly even a crash. Less throw makes your flying smother.

If you are prone to over-control, dial in some dual rates with exponential on computer radios so that a large stick movement results in less control surface m
ovement. If you don’t own a computer radio, you’ll just have to be VERY careful not to move the stick too far or too much.

While were at it, center your servos, then center your control surfaces using clevis adjustment, not sub trim on your computer radio. Did you check for proper control surface movement? Viewing from the rear, stick forward, elevator down; stick back, elevator up. Stick right, rudder right; stick left, rudder left.


I am sure you balanced your ship, but let’s take a second look anyway. If you had to add lead in the nose, you might as well get a larger capacity battery that weighs more. Why not have more juice than lead? You’ll need it anyway for those longer flights you’re going to get after reading this!

While you’re into batteries, consider getting a large
r capacity for your radio. Those small 600 mAh batteries are for wimps! New battery? Did you prime and cycle it for maximum performance? Old battery? Did you cycle and charge for the new season? Best to cycle three or four times to condition the battery for the new season. (NiMH batteries don’t need cycling but do need priming.) Also, double check that balance point. Many newcomers incorrectly balance their plane because they read the ruler wrong or because they read the directions wrong! Use a good CG machine to do this.

Don’t take chances with finger balancing or a homemade rig.


After that, make sure that tow hook is in FRONT of the CG. A good rule is 3/8 inch in front, but if you have an adjustable tow hook, you may move it back to within 1/8 for higher launches. You might want to wait on moving the hook until you have a few launches under your belt.

Now to the field.


At the Field

You’ve just arrived at the field with your spanking new Glider. You put in a lot of hours building it into the perfect ship and now its time to test it out. Scary, isn’t it? Well here are a few tips to help insure your success.

Check everything carefully. Is everything nice and tight? No loose servos or batteries? You did follow the “Before You Get to the Field” instructions, didn’t you?


Always start with a range check, but before you turn on your transmitter, find out if anyone else is using your frequency!!! After assuring yourself that no one is using your frequency, turn on the transmitter, then your receiver (reverse that order when turning everything off). Keep your antenna down and walk out onto the field about 200 feet. Facing the antenna away from the model, have a helper check to see that the control surfaces are moving. O.K.?

Go back to your ship and check for proper directional movement of control surfaces. Remember, look from rear to front. Stick forward, elevator down; stick back, elevator up. Stick right, rudder right; stick left, rudder left. Do all of the control surfaces line up with their stabilizers?

Now you are ready for the next step. It is helpful at this point if you have a buddy to assist. Pick up the sailplane and run forward with it about 15-20 feet. The idea is to get the plane up to flying speed. When you have enough speed, toss the plane out in front of you, keeping it as level as possible. Whether you or a friend does the toss, be ready to input some control surface movement to compensate for dives, stalls or veering left or right. Some guys will run farther and let the ship “bounce’ up and down in their hand to get some idea of what the plane is going to do when released.


Ideally, your ship will glide straight out ahead of you and gently come to earth about 50 feet later, with little or no control surface input. If not, you may have to check your CG, lateral balance, or compensate by adjusting your trims. If you throw the plane hard and it pitches up immediately, you probably have too much nose weight.

Once the toss proves satisfactory, it’s time for the true test. Launch! But first, check to see if your tow hook is in the proper position, hang the plane upside down from the tow ring. It should hang slightly tail down. If it hangs tail up and wants to slide o
ff the ring, you’ll need to move the hook forward. (Note: if one wing hangs down more than two inches lower than the other, see the previous section on lateral balance.

When you do launch, toss the plane hard on launch to get it up to airspeed. Don’t just let it go from your hand. You may want an “old timer” to take her up for the first time, but if you do it yourself, try to launch and fly hands-off as much as possible. Remember, you’re not looking for thermals at this point. You are just trying to get a good feel for the flight characteristics and trim needs for this particular model. Fact is, you should launch and land that new ship 20 or 30 times before you really start thermal hunting.


One thing you don’t want to do in this sport is hurry things up. Take your time. Explore your ship slowly and you will be rewarded with better piloting skills. Practice makes perfect.

Check out the “Trimming” instructions from here.

Trimming Your Lead Sled

Little at a time method.

Try several flights with no wind (early morn or evening). On each flight, try a few tight thermal turns at altitude with slow speed (some up elevator slows your ship in turns). Remove ¼ ounce lead on each flight until plane becomes unstable or tip stalls in turns (Note: dial in additional down trim as you remove weight)

Pay attention to slow speed handling and pitch cha
racteristics. When plane gets mushy, tip stalls a lot or starts slow oscillated pitching, add back in a ¼ ounce lead and call it good.

Note: you will probably need to add nose weight under windy conditions, try ½ ounce at first OR Start with dive test –launch and trim for slow flight (up trim). Come around and fly perpendicular to yourself.

Perform a shallow dive, about 30º then let go of stick. Gradual pull out = O.K. Immediate pull up into a climb = too much up trim holding too much nose weight land and remove nose weight, then re-launch, re-trim and do the dive test again
repeat until the pullout is very gradual (teaching point; if your ship is flying too fast, move CG rearward by removing nose weight; if your plane porpoises a lot, you probably need to remove nose weight) (during the dive test, if the dive angle increases—tuck under-- add nose weight) When it is flying more smoothly, go to early morning test.

Early morning test.

Again, this involves several flights under no wind conditions. Launch (no zoom) and fly straight ahead, hands off as much as possible. Trim the rudder to fly perfectly straight. When she sinks far enough, turn straight back and land. Time each flight and change the elevator trim to optimize the flight times. Once you have determined the optimum trim setting (close to stall), remove 1/8 ounce of nose weight and start the process all over again. Your flight times will increase throughout this process. Eventually, though, she becomes unstable and you have to give so much input to keep it straight and level that flight times start to decrease again. When this happens, put ¼ ounce weight back in the nose and your good to go.

Note: if you’re having to fight for control of your
plane all the time (as with porpoising), you’ve either got too much nose weight (probably the case) or too little. Either way, you’re going to have to adjust the nose weight to get smooth control.

Flying for Fun

Unless you are a competition pilot with a flat wing, full house sailplane, you’re probably just out to have a little fun soaring. Here’s how to enhance your experience. Let your sailplane do the flying. The number one problem with beginners is overcontrol. Too much up elevator will cause a stall, leading to difficulty in trying to regain control to get the plane flying smoothly again. Near the ground, this problem spells BIG trouble. Move that stick in small increments. (Usually, just letting go of the controls will right your ship, without any input from you.) Also, if you overcontrol, you’ll never know when your plane passes through a thermal. Again, let the plane do most—but not all--of the flying. If you read “At the Field,” you will find that it is important to get a good feel for the flight characteristics of your model. You can’t do that when you are constantly yanking the stick. Also, you should have already trimmed your rudder for perfectly straight flight. If you move rudder very much, you won’t be able to see the signal your plane makes when it hits a thermal.

Fly a pattern search. When you’re off launch, turn to the left or right and fly at about a 45° angle until you find thermal activity. If you are getting uncomfortably far out, turn into the wind and come back. Don’t turn with the wind, as you will lose ground and fly in air you’ve already flown in.

Stay out in front of yourself, unless you’ve found that elusive thermal and follow it downwind to gain altitude.

When you see your plane coming down significantly, you have a choice. Either find a thermal quick or join the landing pattern. My advice for beginners, join the landing pattern. In fact, you should practice landings more than anything else, and this should be a separate activity from hunting for thermals.

Landing

Landing can be a scary time for sailplane pilots, especially if you’re new to the sport. If you’re at this point, try these tips:

Don’t bother using spoilers or flaps, if you have them. These will just confuse the issue (and possibly cause a crash). Deploy spoilers and you’ll dive; deploy flaps and you’ll balloon or stall.

Wait to use these until you have some flying experience and can quickly compensate for these effects. (A computer radio can be programmed to automatically compensate for these effects)

Be careful when using up elevator to slow down. You can easily stall this way and, close to ground, that usually means a crash. When landing, avoid using the elevator.

Mentally create your landing pattern and practice it as often as you can, This should be a separate operation from flying for fun and hunting thermals. That’s because your mind should be focused on this one task to get good at it.

Start by entering the pattern at about 50 feet up for a good safety margin. Put in one or two clicks of down trim. This will speed things up but increased speed means better control. Going slower may give you more time to react, but it also creates more opportunity for accidents like stalling. Come to your left or right, as you prefer, and sink to about 20 feet. At this point, you should be about 100 feet out to your side. When you get about 40 feet behind you, start a gentle turn to the left (or right). When your ship gets about 20 feet out from your side, make another gentle turn toward you. Watch that up elevator!


If you are too high on approach, you can turn downwind slightly and come around from the other side of you. You can also zig-zag behind you on final approach to bleed off altitude and energy. If you are too low, shorten the approach by spending less time between turns. Practice, practice, practice!

Keep the wings straight and level, then let her settle in. You can give slight up elevator when she is about a foot above ground. This will slow the model. (Remember, when you are looking at the nose of your plane coming toward you, move the stick in the direction the wing is dipping. This is opposite of when you are looking at the tail of your plane in front of you.) If it rolls right past you and seems not to want to land, just let it go. It’s better to walk a distance to your plane than to pick up the pieces at your feet. Next time, fly a little further past yourself before making the turns.

When it’s windy, don’t fly past yourself. Make your first turn when your ship is at a right angle to you or even in front slightly. That’s because the wind will carry it downwind by the time your make your final approach.

Have fun!

Monday, February 4, 2008

10 Simple Flight Safety

1. No flying overhead.

2. Avoid flying over any spectators.

3. Before executing a low pass or low flying stunt, always check that the path is cleared of other flyers or park users.

4. Always fly within the perimeter defined by the boundary of the park, never over highway or roads.

5. Always sound out ("Landing") to alert others before coming in for landing. Always sound out ("Man on Runway") before going onto the runway while others are flying.

6. To avoid mid airs collision when flying as a group, always makes your intention clear and fly in the same direction as others.

7. Ensure frequency is cleared before turning on your radio, this is especially so when someone else is already flying.

8. Do not to hog the runway.

9. Avoid flying alone at the field, accidents do happen, your flight buddy could well save your life during such emergency.

10. Remember your model is not a toy but a piece of potentially lethal machinery, never compromise safety of human life, crash your model to abort flight if need be.

Clubs' Rules

Model Airplane Clubs Rules

• The flying field must always be well maintained and kept free from debris. Club members are responsible for keeping trash picked up and properly disposed of.

• All automobiles are to be parked in the designated area and behind the pit line at all times.

• Transmitters in use on the field must have the proper frequency ribbons displayed.

• When arriving at the field, you are responsible for checking that your frequency is not in use prior to turning any RC equipment on.

• Flying is only allowed at designated club sites.

• No flying is to be done behind the pit line.

• People learning to fly, who have not yet been cleared by a club instructor to fly solo, are required to get assistance from an experienced flyer prior to flying in front of any spectators.

Thursday, January 10, 2008

Nitro Powered RC Cars - Tips for Choosing Your First Gas RC

RC (radio controlled) cars, especially the nitro or gas powered RC cars, are becoming increasingly popular. With speeds up to 70 mph, realistic looks, and racing clubs in virtually every large city, it's easy to see why.

If you want to join this exciting hobby, there're a few things you should consider before you buy your first nitro-powered RC car. The basic considerations are: size, type, 2 or 4-stroke motor, maintenance, 2 or 4 wheel drive, and ready-to-run (rtr) or kit cars.

Sizes
The two most popular sizes to choose from are 1/8 and 1/10 scale. 1/10th scale is the industry standard for on-road racers, while 1/8th is more popular for off-road trucks and buggies. The larger 1/8th scale on road car comes standard with a 2 or 3 speed automatic transmission.

Types
The touring and racing cars are are the popular choice for on-road use. For best performance, they should be run on a smooth surface.

Trucks and buggies are the choice if off-road action is what you want. Though not as fast as the touring and racing styles, they are still very impressive and extremely rugged as well. And since a smooth surface is not required, they also have the advantage of being able to run just about anywhere.

Motors
Nitro powered RC motors come available in the popular 2-stroke or the less conventional 4- stroke versions. The primary difference is that the 2-stroke motor, much like a weed eater or chain saw, requires a fuel oil mixture. The 4-stroke motor has an oil reservoir and can run on straight fuel. The 2 stroke engine has the advantage of producing higher rpm's (revs up faster) and is more suitable for racing. The 4 stroke engine has more power and torque and is better for offroad use.

The most popular 2-stroke motor is the 23cc (cubic centimeter) displacement engine. It's popularity is due to the amazing 2.5 HP of output it produces. The resulting high speeds and acceleration are what RC racers love.

Additionally, motors come with or without a pull start. The ones without a pull start are cheaper, but you'll also need a starter box.

Maintenance for Nitro Powered RC Cars
Maintenance is a definite requirement of running a nitro powered vehicle. Most hobbyist love tweaking and tuning their vehicles. In addition, you'll need to maintain certain parts such as:

Clutch
Differential
Air Filter
Header and
Pull start cord

2 or 4 Wheel Drive
If you're new to the hobby, you'll find a 2wd car less expensive and easier to work on. The 4wd car has the advantage of better traction and handling in turns which makes it a better choice when you're ready to race.

Kits or Ready to Run (RTR) Rc Cars
Nitro powered rc cars come in kits or ready-to-run right from the box. The primary difference is the whether you want to save time with a RTR car or save money with a kit. However, because of the assembly process, kits better prepare you for required maintenance.

If you choose to build an rc car, don't expect to finish in one sitting. To avoid mistakes, familiarize yourself with the instructions first and get your work area prepared. Some of the things you'll need are:

Small No. 1 and 2 Phillips and flathead screwdrivers
Soap - as a dry lubricant for tight parts
Extra fuel line - to hold screws while positioning
Needle nose and regular slip joint pliers
Flush cutter
Hobby knife with no. 11 blades

When you assemble the car, make sure to work in a well-lit, uncluttered area. You should keep the parts and tools separated using tin boxes, trays, or even an old fishing tackle box.

These are a few of the basics you'll need to know before you buy your first nitro rc car or truck. You should expect to pay around $400 for a complete beginner setup. The price will vary a little depending on whether you choose a kit or RTR and how many tools you need.

Whether you race or just practice by yourself, get ready for a lot of fun!

Wednesday, January 9, 2008

What Type of RC Car

So you’ve you decided you like the simplicity of the electric RC’s, or the realistic sights and sounds of the nitro class. Now the next decision is just what type of RC vehicle is best for you. Choose according to what you plan to do with your RC, and your level of experience.

On-Road
On-road cars are the most popular type of RC cars. The standard for on-road cars is 1/10 scale cars, though 1/8th scale RC’s are not uncommon. The recent increase in micro and mini RC’s means there are hobby quality on-road cars made as small as 1/18 scale. Both nitro and electric RC’s come in on-road versions, and are available ready to run or as build your own kits. Built and geared for speed, an on-road RC should be your choice if you plan to race your car. Touring cars need a smooth, paved surface on which to run though even running up and down the street you’ll be amazed by their speed.

Off-Road
If you want to be able to run your RC just about anywhere, you’ll definitely need the rugged construction of an off-road vehicle. These sturdy cars and trucks will handle jumps, uneven terrain, and hills, even sand. They come in two- or fourwheel drive versions, and are perfectly capable of driving in your back yard, a vacant lot—just about anywhere.
Like their on-road counterparts, off-road RC’s can be purchased ready to run or as build your own kits. There is a wide variety of both electric and nitro cars and trucks from which to choose. Off-road RC’s, though not the fastest cars available, are durable, rugged and can be run practically anywhere.

Touring and Racing Cars
The touring and racing cars are perhaps the most common type of RC's. The wide variety of styles and cars in both electric and nitro kits makes them an easy choice for the beginner, and the higher end build your own models can be great for advanced hobbyists. Lightweight and fast, these are the ideal racers.

Trucks
If off-roading and rugged, sturdy vehicles were what you had in mind, then a truck is likely to be the RC for you. Both electric and nitro monster trucks are fast, tough RC's for running off-road courses. The ready to run RC trucks would be suitable for beginners.

Buggies
These durable little RC's are powerful enough to handle on- and off-road terrains with speeds up to 60 mph. Usually only available in nitro kits, they are a lot to handle for a beginner.

Monday, January 7, 2008

RC Car Sizes : Standard, Micro or Mini

Once you know what type of RC you want, you need to decide what scale it will be in. Hobby quality RC cars come in a few different sizes: as small as 1/18 scale and as large as 1/8 scale. Nitro and electric cars are usually made at the industry standard 1/10 scale. This can be confusing for a newcomer, but if you’re in any doubt about the size of the RC you’re interested, just as at a local hobby shop and make sure it’s what you want before you buy.

To give you an idea of the amount of variety available when it comes to scale, this is a brief rundown of the sizes of nitro RC’s on the market today, as given by a prominent web retailer (http://www.shipshewanatoys.com):
• 1/10 scale touring cars:
Engine powered touring cars can be extremely fast, reaching speeds up to 55mph. As with electric touring cars, nitro vehicles feature 4WD and realistic body lines, and are only meant for on-road use.
• 1/10 scale stadium trucks:
Nitro stadium trucks are identical to electric stadium trucks, except for the engine power. They're suitable for racing or recreation, on or off road, averaging a peak speed of about 30mph.
• 1/8 scale monster trucks:
These monsters are equipped with major horsepower. Consequently, they can travel on-road and off-road up to 40 mph, tearing through and over anything in its path!
• 1/8 scale buggies:
Similar to other 1/8 scale vehicles, they have the power to traverse rough terrain on-road and off-road, are very durable, and travel up to 60mph.
• 1/8 scale on-road cars:
The revolution of RC performance, these vehicles reach speeds of close to 80mph, coming standard with shifting 2- or 3-speed transmission. Intended for experienced enthusiasts, their foam tires provide tremendous grip, and they are suitable for smooth on-road courses only.

RC Micro and Mini Cars
The most recent development in RC in the last decade or so has been the introduction of micro and mini-sized RC from Japan and throughout Asia. These tiny but powerful little RC’s offer the same racing excitement as the big boys for only a fraction of the cost.

Only recently introduced to the North American market from Asia by companies like Radio Shack, micro RC’s offer an extremely low price-point for out-of-thebox racing fun. Priced at $50 or less, these are a great choice for a driver not ready for a full-sized RC or a newcomer to RC racing who wants to see what all the fuss is about.

Measuring only 2 ½” inches long, micro RC’s feature the same kind of motor that makes your cell phone vibrate. Best of all, these little engines are interchangeable, so you can tweak you micro RC with a different motor for more speed. Specialty tires and hubcaps can be added to customize the look of your micro RC, as well as enhancements to the torsion and steering controls. Mini and micro RC’s are always ready to run, right out of the box. Your little RC will come with the following:
• rubber non-stick tires
• micro scale working engine
• realistic, running chassis
• receiver and circuit board
• transmitter
• customizable body

The greatest advantage these little cars offer is their versatility. Unlike the noisy, smoky nitro cars, or the load hum of an electric race, micro RC’s are clean and quiet. They can be run indoors or out, even in your garage or basement. This means you don’t have to wait until the next race to run your car—these are small enough you can drive them anywhere.

Mini RC’s, like their standard-sized electric cousins, run on rechargeable battery packs. When your car is out of juice, it usually pops into the controller itself, which is then plugged into the wall. With your transmitter doubling as your charger, your car will be ready to race again in under a minute. If you want to race longer, the fast recharge time for these tiny RC’s is a great selling point. Overall, though they are not as customizable and intricate as the larger 1/10 and 1/8 scale cars and trucks, micro and mini RC’s have the same acceleration, controls and feel. Their tiny size makes it possible to run them anywhere from your garage to the kitchen floor so you can race any time you like—down the hall or up the street!

For about a quarter of the cost of a regular RC, you get a car with responsive controls, tunable suspension and customizable exterior But, like their larger counterparts, you can still get the kind of car you’re after: mini and micro versions of all the most popular vehicles are available. They’re the ideal option if you’re on a limited budget, but are still eager to get to the race.

Electric or Nitro Powered RC Cars

Just like buying a real car, deciding on an RC car takes research, price comparison and evaluation of your own needs. Though all RC’s have the same components—transmitter, receiver, motor, and power source—they vary widely in size, type, and degree of difficulty.

The first, most important decision to make is whether an electric or a nitro car is right for you. Nitro powered rc cars tend to be faster and more powerful, though their engines require a lot of maintenance and tuning. Electric powered rc cars, on the other hand, don’t run quite as fast, but they’re easier for beginners and run much quieter. Secondly, once you’ve decided whether an electric or a nitro car is best for you, you need to choose between a car that is ready to run right out of the box and a kit that you build from scratch. Ready to run cars are easier for beginners anxious to get to the race, though the build your own kits give you a better understanding of how RC’s work since you build it from the insides out. If you’re not sure, keep in mind that most ready to run kits still include full instructions should you ever want to take apart your RC or replace some of its parts.

Next, you need to decide just where you’ll be driving the car. Just like you wouldn’t buy a gas guzzling SUV if you live downtown and have a long commute, you’ll want to make sure you buy the RC that suits the kind of driving you’ll be doing. On-road RC’s are built for speed, so if it’s racing and road running you have in mind, you’ll want to stick to these lighter, faster vehicles. If you want to practice on rugged terrain and with jumps, the more rugged off-road RC’s are probably best for you.

The last thing to choose is the size and type of RC vehicle you’d like. The most popular class of vehicles are 1/10th scale, but there are also larger 1/8 scale and smaller mini and micro sized cars. Plus, the best part is you get to decide just what kind of RC vehicle you’d like best—there are cars, trucks, buggies, boats, planes and even helicopters to choose from.

Sunday, January 6, 2008

Electric RC Cars

Electric RC cars and trucks are generally considered best for beginners, since even if you choose to build your own car, they tend to be simpler and easier than nitro cars. They’re also a great deal quieter and run much cleaner, meaning you’re less restricted by where you can run them. In terms of speed and power, they do have a great deal of pickup, though not as much as the nitro cars.

Electric RC cars use rechargeable battery packs to power their motor and steering, which are usually recharged from a 12-volt car battery or wall socket. Batteries run for about 5-10 minutes, depending on the type of engine your car has, and charging the battery usually takes 15-30 minutes. Because of this, it is strongly recommended you have at least two battery packs, to allow for quick replacement of the battery. This means your car can keep running while the other battery is recharging, giving the car more overall running time.

At first glance, getting started with an electric RC car can be much less expensive than a nitro vehicle. But there are other costs to consider as well, such as additional battery packs, a battery charger and other accessories that will add to the cost, making it closer to the price of a nitro car in the long run. Of course, this cost also depends on what kind of car you end up purchasing and what kind of battery pack it requires, as well as how often you run the car and the quality of the batteries you get. Though the initial outlay of cash can be steep, but you’ll want to get quality battery packs and a good charger to save replacing cheaper batteries.

The main reason electric RC’s are said to be easier than nitro is in the amount of maintenance and tuning their engines require. Though the care, maintenance and cost of battery packs is steep, it is still less trouble for the new driver than the air filters, tuning, fueling and various other engine parts that require attention on a nitro car. Instead, careful conditioning and proper storage of your battery packs will keep your electric RC car running smoothly for years. Always consult your manufacturer’s instructions to make sure you’re getting the right battery packs for your car, and that you’re caring for them properly.

Easier and cleaner, electric RC cars and trucks offer the genuine racing experience to the beginner on an easy learning curve. Proper conditioning and maintenance of the car and its battery packs are still easier than the many parts and problems often associated with nitro RC’s. If you’re a beginner, or if you just want to get to the races, an electric RC can offer you the speed and fun you’re after for less work.

Also keep in mind that if you think you’d prefer an electric RC, but still want the experience of building your own car, that you can also purchase electric kits. These include complete instructions to build your own car from scratch, and because their systems are less complex than the nitro cars, they are a little easier to build yourself.

Electric RC Car Motors In order to prevent unnecessary wear and tear on your electric motor, it is important to always break in your motor, before you drive it for the first time, and every time after you change its brushes. One easy method is to run the vehicle with the wheels off of the ground at about 1/4 power for about 5 minutes. This will slowly get the brushes fully seated to the commutator without causing wear and tear on the engine, and will allow your motor to run at its full potential. Your electric car will come with instructions on how to change the brushes on the motor, as well as guidelines for how often. Remember, if you change the brushes on your motor, be sure to break it in again. How often you replace the brushes—and the motor, for that matter—depends on where and how much you’re running or racing your car. Generally, a motor should be replaced after it has gone through five or more pairs of brushes, but it will always depend on the individual car, its motor and how well they’re running.

Saturday, January 5, 2008

Nitro Powered RC Cars

Nitro RC cars are named for the special type of fuel that gives them and their motors such kick. Though not the best choice for beginners, they are the choice if speed and power are what you want from your RC. The great popularity of nitro RC cars and trucks is due not only to their speed, but is also because of the realism they offer—sights (smoke), sounds (tuned pipe) and smells (exhaust) just like the real thing! Over the last several years, the quality of nitro RC’s has been greatly improved, making them safer and more reliable than in the past.

There are four defining features of a nitro RC car:
• special nitro fuel
• high horsepower nitro engine
• tuned exhaust pipe
• Realistic, replaceable air filter.

Two different power sources are required for a nitro RC car, starting with battery packs for the transmitter and receiver. The car itself, as the name suggests, really does use gasoline as its fuel: an oil and gasoline mixture, much like a real car. There are two kinds of nitro motors: the 2-stroke and the 4 stroke engine. The more popular 2-stroke engine is similar to the kind of engine found inside motocross motorcycles, chain saws and weed whackers. This type of engine has no separate oil reservoirs, so the oil that lubricates it is included in the fuel mixture. Conversely, the less popular 4-stroke engine does have an oil reservoir and therefore depends less on a gasoline/oil fuel mixture for lubrication. When running or racing, the car’s fuel tank will need refilling every 5 to 10 minutes.

The engine seen most frequently in nitro RC cars today is a 23cc (cubic centimeter) displacement, 2-stroke engine. Its popularity stems from the fact that it’s among the most powerful engines available for nitro RC cars, putting out approximately 2.5 HP from its 23cc displacement (23cc means that the engine has about 1.4 cubic inches of engine displacement). This engine would be certainly powerful enough to impress you with its speed.

You’ll need a starter for the engine, of which there are two types:
• a pull-start nitro engine (these use a process like your lawnmower to start)
• Or a non-pull nitro engine (these fire up with a starter box).
The pull start nitro engines cost a little more, but you don't have to buy a starter box and it's less you have to carry around to run your vehicle. Just take it out, pull on the starter, and you're ready to go! Be sure to check your instructions to choose a starter that’s right for your car.

To keep your nitro RC running at its best, constant maintenance is necessary. This includes keeping the engine clean and well-tuned, setting it up correctly and using good clean fuel. As well, if you’re running your RC off-road, you’ll need to make certain it is properly cleaned after you run it, otherwise dirt and grit can slow down or even ruin your engine. Any special procedures particular to your car will be outlined in your owner’s manual. Remember that your engine will only run as well as you treat it—so take great care of it, and you’ll never have trouble on race day.

Fuelling Your Nitro RC Car
Nitro RC cars run on a blended fuel easily available at local hobby shops or online. It is made up of a blend of methyl alcohol (methanol), nitro-methane (nitro), and oil. In order to understand how nitro fuel work, you need to know what each of these three components does for the car:
• Methanol provides the main power to the engine and is the main ingredient in model fuel. It has an ignition point that allows it to be ignited with the kinds of platinum-element glow plugs used in RC engines, and it releases more energy per pound of air than gasoline. Because it’s easy to get, it’s not expensive—you’ll find model fuel much more reasonably priced than regular gas.
• Nitro-methane is added to assist the idle and acceleration and to enhance power output. Nitro is referred to as a “hot fuel,” and is only used in small amounts in model fuels. It can be explosive if not handled correctly, so take care to read the fuel tips offered here, and always follow the manufacturer’s instructions when filling up your RC.
• Oil is need as a source of lubricant for all the moving parts in the engine. Here 2-stroke and 4-stroke engines will require different fuels, since 2- stroke engines have no separate oil reservoir, and need oil mixed in with their fuel. There are two types of oil found in model fuels- castor oil and synthetic oil. These can be used by themselves or in a blend, with synthetics being far more common these days. This is mainly because synthetics are cheaper and less gummy than castor oil, which used to be the only oil used. For some engines, a blend with a large percentage of castor oil may work best, since it is actually a better lubricant at higher temperatures. The synthetics are far less messy, however, and leave less gum on your engine. You’ll be able to choose from blends of synthetic and castor oil that vary in their percentages- try out a few to find one that runs your engine best.

RC fuel blends are expressed in percentages based on the amount of each component ingredient used, and of course the one right for you will depend greatly on your car and engine. Most model fuels contain mainly methanol, to which about 20-22% oil and 10-15% nitro is added. Be sure to check your owner’s manual for suggestions and guidelines about which blend is correct. Bear in mind that you may have to try out a couple of different types and blends before you find the one that’s right for the way your engine is tuned. And if your engine isn’t running properly, one of the first things you should do is change the fuel. Taking proper care of your nitro car’s fuel is extremely important. Not only will it help your car run better and make for less wear on the engine, model fuels are flammable and could be dangerous if not properly stored.
• Nitro fuel should not be stored in unsealed containers. Because methanol mixes easily with water, the container you store it in should be completely air tight. Otherwise, air could get in and evaporation or condensation could occur, ruining the fuel. It will cause your engine to run too hot and be quite damaging to your car’s fuel and exhaust systems.
• Store your fuel at room temperature, and at a constant temperature. Again, you want to avoid any air in your container or in the fuel, which temperature swings can cause to condense. Do not store your model fuel in a room that varies widely from hot to cold or vice versa.
• Keep model fuel away from light. Nitro methane degrades in light, which means you need to store your model fuel in a cool, dark place. If you leave it exposed to sunlight or store it in a brightly lit place, the nitro will degrade completely, as though it hadn’t even been added to the fuel in the first place. This will cause your engine to run very poorly, or cause poor starts or stalling.
• Do not store fuel more than a year. In addition to following all these steps, you must also replace your model fuel frequently. Though proper storage will keep your fuel fresh and running clean, it cannot be stored for years and years. Most manufacturers offer some guarantees on their fuel, but these will not apply if you have stored it for an extended period of time. Most importantly, old fuel can be dangerous, so don’t leave it stored indefinitely.

Nitro Engines: 2-Stroke
The 2-stroke is the engine most commonly found in nitro RC’s. “Stroke” is meant by the number of times the piston travels through the engine sleeve in the combustion chamber. 2-stroke engines produce power in one cycle, which is divided into the two “strokes.” The piston has two positions: top dead center where the cycle begins and ends, and bottom dead center, which is the middle point of the power cycle. Combustion causes increased pressure in the chamber and forces the piston down. As this occurs, the exhaust ports are opened so gases can escape through the manifold. The second stroke begins when the piston reaches bottom dead center and the crankcase and then moves back up the engine sleeve. This causes the pressure to build up again as the piston approaches TDC once again, completing the power cycle. The next stroke occurs as soon as combustion from the glow plug sparks it again.

Nitro Engines: 4-Stroke
Less common but more powerful, 4-stroke engines are more like what you’ll find under the hood of your real car or your lawnmower. Though similar to a 2- stroke, a 4-stroke engine has 2 full cycles with 2 strokes of the piston each (for a total of 4 strokes). Unlike the simpler glow-plug ignition that a 2-stroke uses, a 4-stroke regulates the air and fuel in the chamber with a geared cam mechanism. Intake timing is how much and when this air/fuel mixture enters the cylinder, while exhaust timing refers to the escape of hot gas from the cylinder. The easiest way to understand what happens in the 4-stroke power cycle is imagine the 2-stroke cycle simply stretched out to get the most out of each segment of the piston’s movement. The piston begins at TDC and as it travels down the cylinder the geared cam allows fuel and air into the combustion chamber.

The intake valve closes when the piston reaches the bottom of the cylinder, which is then forced back up by the flywheel and drive train components. This compresses the air and fuel, and the pressure causes combustion as the piston reaches the top of the cylinder again, completing what is referred to as the compression stroke.

As the fuel mixture ignites it initiate the so-called combustion-stroke, during which the piston travels back down the cylinder and up again. In the final “power” stroke the gases are forced out to the exhaust systems—just as in the 2- stroke engine. The cycle is then repeated.

4-stroke engines rely on intake and exhaust valves to complete their power cycle. This is combined with a number of other features—a moving crankshaft, several valve-train components, camshaft, rod and pistons and the geared cam mechanism—to make a more powerful, but more advanced engine. The improved management of fuel and air flow in and out of the engine makes the 4- stroke more efficient, though their advanced mechanisms mean they require meticulous attention and maintenance.

Nitro Maintenance and Tuning So now that you know what’s under the hood of your RC, there are few more tips that will help your car run better:

! Improve your acceleration by proper preparation of your clutch. Over time, a glaze can form on the clutch and the clutch bell, which causes the car’s acceleration to noticeably decrease. Scuffing both the clutch shoes and the clutch bell with fine-grit sandpaper or steel wool and a good cleaning with motor-spray will remove this glaze, and prevent the clutch from slipping against the clutch bell.

! Extend the life of your car’s differential by breaking your motor in gently. Your car’s differential filled with small, complicated gears that make them both complicated and expensive. This is not a part you want to replace frequently, but carefully breaking in your car before racing or running it full out can greatly extend the differential’s lifespan. To break in your engine, run it at ¼ power a few inches off the ground, and then run some slow, steadily powered figure-8’s. This should set the gears in the differential and you can run it full out without damaging the engine. Make sure you keep your header in position.

Your car’s header is attached with a tiny spring, meaning it comes off very easily if you hit something or if your car gets hit by something. If you’re racing, this can be a huge problem to put back on in a hurry, so be sure to attach your header to the engine block more firmly using a small piece of safety wire. Make sure you twist the wire firmly around the header and be sure to cut off any excess.

! Brace your air filter to prevent losing or damaging it. The small piece of the same safety wire that secures your header should also be used brace your filter. Again, twist it tightly to prevent the filter from becoming loose and remove any excess.

! Protect your pull-start cord from fraying and breaking. Over time, the cord of a pull-start engine can often become worn and frayed. This can be prevented by covering the edges of the opening- try duct tape or cutting up a small section of fuel tubing. Make sure not to obstruct the opening, but rather create a smoother edge to the opening for the cord get in and out of with out fraying. Never leave your pull start cord pulled all the way out- if this happens, it could get stiff or be impossible to reinsert

! Follow your manufacturer’s instructions for the best results. Your car will come with complete instructions and owner’s manual, which you should read carefully for all specifications and any technical issues you have with your RC. Should you run into something you can’t fix or an engine that simply won’t run properly (or at all!), it’s best to consult your local hobby shop for some expert advice and help.

There’s nothing like the realistic roar and smoke of a nitro RC, which are fast powerful enough to make for some exciting races. Bear in mind however, that nitro cars and the engines that power them are very complex, and as such require frequent tuning and meticulous care—much more so than an electric RC. Because of greater complexity, you will also find they tend to be more expensive, as well. What this means to you as a driver is that you need to decide in advance what your budget is and just how experienced you are with engines and RC racing.

If you’re beginner but you still have your heart set on a nitro car, they can be purchased in ready to run versions that will get you in the race as soon as you open the box. Although these still require the same ongoing attention and maintenance, you will be saved the initial trouble of building the car from scratch.

Ready to run nitro cars and trucks are more expensive than the ones you build yourself, but they’re far easier if you’re still unsure about your mechanic ability. Also, since even ready to run kits contain complete instructions on how they go together, you can rest assured you’ll be able repair, maintain and add on to your car for a long time to come.

The main attraction of nitro RC cars is their realism and their power—they’re fast, they roar and they smoke—just like real cars! They can be tuned to reach speeds up to 60 mph and they can race as long as you keep filling the gas tank. Though not recommended for complete newcomers to RC racing, nitro RC’s are by far the most popular.