Based upon numerous private requests as well as teh "how can we help you" thread, I'm going to give this a try...please let me know what you think!

I'll try to remember to drop by every Thursday and pass along a helpful hint, tip info or tidbit, to fit various areas of the hobby -- car, air, radios, etc.

Most will be links to our F.A.Q.s which will hopefully show you other helpful info as well. Some will be new data based on customers or personal questions here (which will likely become FAQs in the near future!).

Please let me know what you think!!!

Here comes the questions of the week...

AIR:
Why can't I buy plans to repair my ARF?
http://www.greatplanes.com/faq/service-faq.html#q21

Unfortunately, ARF models are not built over plans like those used by a single modeler to build a model kit. Therefore, we do not have any type of plans to provide you for rebuilding your ARF model. However, wing sets, tail sets, fuse sets, and other parts are available for nearly all of our ARF models for purchase through your favorite hobby shop.

Please note that creating a quality set of plans for a model typically takes as much of the designer's time as all other steps in the design process combined. Therefore, it is just not feasible to create them for those kits that don't have a dire need.

For some really helpful info on reading plans and why they take so long, please see:
http://www.greatplanes.com/reviews/readingplans.html



CARS:
My car tends to pull to one side or the other, how do I get it to go straight?
http://www.duratrax.com/faq/faq-q459.html


ENGINES:
My new engine is VERY hard to turn over. I can't get it past one point by hand at all. Is it defective?
http://www.osengines.com/faq/product-faq.html#q1
An ABN engine has an Aluminum piston and a Brass liner with Nickel alloy plating.

A ABN engine's liner is tapered towards the top. This causes the piston to "grab" as it moves towards Top Dead Center (TDC) when the engine is cold. (Some engines will actually seize if you turn them over when cold, requiring considerable force to turn them through TDC.) When an ABN engine is run, the heat of combustion causes the metal parts to expand. Because the piston and cylinder liner are made of different metals, they expand at different rates. The liner expands just enough to make a nice fit for the piston once the engine warms up. The liner is tapered because the cylinder is hotter near the top. The different temperatures cause different amounts of expansion, making a perfect fit when your engine is at optimum operating temperature.

You may interpret what you feel as play in the connecting rod. This is almost never the case with a brand new engine. What you are feeling is a slight springing of the connecting rod as you force the engine through TDC. The piston doesn't go all the way to the top, causing the rod to flex slightly, which gives an "over the center" feeling. Many people have interpreted this as play in one of the rod ends, but it is not and is perfectly normal.


RADIOS:
What is exponential? How about ATV?AFR? AST? DR? ATL? EPA? Triple rates? what do all these terms about how far my servos move mean?

All of these terms are computer radio features (many are also available but adjusted mechanically with "pots" {dials} on non-computer radios) that are used to adjust how the model performs without having to make physical installation/linkage changes. In many cases, you can not get a mechanical linkage to give you a small enough (or large enough) amount of travel for the model to fly its best. These functions let you adjust those travels for optimum performance/safest flight.

ATV has developed into a slang term meaning how far the servos move at their extremes.

EPA is a specific type of ATV in which each end is adjustable separately. For example, the throttle servo can be adjusted at idle separately from high end.

AST is basically ATV where you get just one setting that affects both ends of the travel. If you turn it down to 90% both right aileron and left aileron will move only 90% of the total distance the servo is able to move on its own.

D/R is the common abbreviation for dual rate. What dual rate means is that you have one rate or total distance the servo/surface will travel...lets say it is 1/2" on an elevator. A 50% dual rate would mean that when you throw the switch, the servo moves exactly half as far per stick position as it did on the first rate. So the elevator stick all the way up is now on 1/4" travel instead of 1/2". Similarly, at half stick it is now 1/8" instead of 1/4".

Triple rates is just an extension of dual rates where 3 separate travels are available in flight. Triple rates are normally only used by top level aerobatic competitive pilots to have one setting, say, for take off/landing, one for normal flight, and one for complex aerobatics.

AFR is a very specific function in the 9Z which is basically the same as "high rate" on most dual rate setups. It is a second adjustment for how far the servos move when given normal stick commands (as opposed to commands from mixes, etc) separate from the ATV. The 9Z separates dual rates into AFR and DR to allow more flexible setup of all 8 channels' high rate travels. For details: http://www.futabarc.com/faq/faq-9z-q111.html

ATL: ATL is actually a trim function. What it means is that the throttle trim affects only the bottom half of the throttle stick. This way adjusting your idle does not affect your wide open engine performance.

For more details on these and other specific terms, please see:
http://www.futabarc.com/glossary.html


Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
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