To begin with the model must be constructed as accurately as possible. Any deviations from such basics as thrust and decalage setting during construction will have to be corrected during the flight trimming process. Results from such practices are usually at best unsightly or elso require considerable effort to camouflage. So initial efforts to get these basics correct will be most beneficial during the flight trimming process.

Warps that result from hasty building practices are much worse than those that result from covering. Built in warps, twists, and misalignments are practically impossible to correct. Slight warps usually in control surfaces caused from covering can be corrected. Needless to say any warp will only serve to aggrevate the flight trimming process, and may even make it impossible to properly trim the model if severe enough.

It is possible to flight trim a model of excellent design, built to absolute accuracy to fly like a real dog. Only a mode with superior design features plus proper flight trimming can result in a model with superior flight characteristics.

Do not dismay. While all of the above has a direct bearing on trimming a model for flight not many models have been built to such standards. In fact not very many have been trimmed out to perfection. A combination of model design, flight trim, flying skill and equipment reliability and accuracy all combine with a bit of lady luck to produce a winner. So proper flight trim is only part of the expert's bag of tricks and this can be mastered to the degree necessary to materially increase the enjoyment of flying by any RC’er. Only experience can lead to a satisfactory degree of perfection but experience can best be gained while working with a pattern of basic techniques. I have found the following step by step procedure to work well with any type of model.

Three Step starting procedure:

1. Trim for hands off upright level flight while using full power. (Consider trimming for level flight using a cruise power setting since our Powerplants are producing much greater power than when orginally written ) Normally only elevator and aileron trim is required.

2. Trim for inverted straight flying using only down elevator to maintain altitude. If the model has a persistent turning tendency in a given direction, trim rudder in the same direction as the turn until no turning tendency is present while flying inverted. If rudder trim was required retrim ailerons for up right level flight. Repeat inverted straight flight trim until model fly’s straight, level, and true both upright and inverted. If a lot of down elevator is required to maintenance altitude, check center of gravity, decalage, and thrust settings. Correct as necessary and repeat steps one and two.

3. Trim for glide condition. Fly by upright and level with full power. Cut power to full idle. Model should continue on a straight line, with no tendency to suddenly balloon or dive. As speed decreases the nose should gradually drop but only a slight amount of up elevator should be required to maintain a constant speed and rate of decent. If ballooning or diving occurs when power is abruptly cut to idle, then change thrust angle. If a lot of up elevator is required to maintain the glide, then CG or incidence setting should be checked and corrected. If the model is to be used in competition the flight trimming process must be continued if full potential is to be reached. So the next requirement is to be the deflection angles for the elevator, rudder and ailerons. Two factors govern our efforts in setting up these deflections. First is the need to achieve maximum benefit from the human reflex system, whereas in the reflex action are as even as possible on all axis of control. I call this a balanced feel of control where the models response is the same in either direction for each control. The Second factor is to determine the deflections limits in maneuvering requirements. Each control must have sufficient deflection to perform each maneuver best. Elevator: The requirement of the spin is a primary factor in setting up the elevator deflection limits. The elevator must be able to put the model in a stalled condition and hold it in a stalled condition. The elevator deflection angle for most designs is approximately fifteen degrees but may be as little as ten degrees or as much as twenty degrees. Since limited elevator sensitivity is important for smooth execution of most all manuvers, the deflection angles should be set as low as possible but with an equal amount to either side of neutral.

When split type elevators are used it is most important that the trailing edges of the two elevator halves be in perfect alignment. Any attempt to flight trim a competition RC model by misaligning the elevator halves could best be compared to trying to correct an automobile's steering discrepancy by misaligning the real wheels! The results would probably be similar also!

THE RUDDER: Any rudder deflection beyond about thirty five degrees does not do much more than apply air brakes. If the rudder will not do what it is supposed to do with thirty five degrees of deflection it needs more area. The amount of deflection is determined by how much is needed to do a dead straight hammer-head stall, to either right or left, with no wind present. Any more than this will turn the spin into a real tail twister!

THE AILERONS: Both the double immelmann and three rolls are used to determine the amount of aileron deflection. This amount is four seconds for three rolls. At this point try to achieve a "balanced-feel" between the ailerson and elevator by making slight adjustments. It is now necessary to adjust for proper aileron differential. It is easiest to determine if the differential is correct by doing a split S from a long straight away climb out. If following a LEFT 180 degree roll , the heading has veered to the LEFT , there was too much differential. IF the veer was to the RIGHT , there was not enough.

Loop Tracking.

This is probably the biggest bugaboo of all. No wind and stable air are both a must if experience is lacking and a definite help in any case. Inexperience could also use a helper to verify what happens and jot down information for analysis during the relaxing periods between flights.

To trim for loop tracking requires both inside and outside loops be flown with the model heading straight away from the pilot. Try a inside loop first and use no command other than elevator one loop at a pass. Note which direction the model turned, right or left, and if a turn did occur which wing went to the outer perimeter of the loop. Now do an outside loop , using only elevator and note turn direction and wing deflection. At this point you are interest only in whether a wing did deflect in both inside and outside loop. If the same wing panel moved outward in both inside and outside loops, then that panel is heavier and weight must be added to the lighter panel's tip. (1 ounce=28.35 grams..a US quarter =6 grams)

If the same heading change occurs at the beginning of both inside and outside , the rudder must be trimmed to correct. If a change in rudder trim is done, the ailerons may need trim change.

If the same heading change occurs as you approach the TOP OF THE LOOP, the problem is engine thrust setting. Right or left thrust must be changed.

If the model will track doing insides but will NOT TRACK while doing Outsides then raise the ailerons. Depending on the degree of improvement or aggravation of the outside tracking tendancy either raise or lower the ailerons more or less. Continue this process until the model will track properly during ONLY ONE LOOP.

If it will track through one loop it will track through three unless the slipstream from the preceeding loop or wind causes the model to veer. For this reason no three perfect loops can be done with only elevator.

There you have the basic flight trim techniques. In loop tracking there are two or three adjustments. Trying to analyze the first loops may be frustrating. Recognize a heavy wing and correct for it..Recognize rudder trim and correct for it. It is an advantage in having someone help if the model turns out to be difficult to trim.

A note not from Mr, Kirkland..may have come from Wolfgang Matt "If model will not trim properly, Discard model."