Symposium on Free Flight Adjustment Part II
March 1957 American Modeler
This is part two of a series from the March 1957 American Modeler that briefly introduces a dozen winning free flight models and comments from their designers. Current day modelers who like to fly the vintage (old timer) airplanes might pick up a useful tip from the masters of the golden age of free flight.
March 1957 American Modeler
[Table of Contents
Aircraft modeling has undergone significant
changes over the decades - both in technology and preferences. Magazines like American Aircraft Modeler, and American
Modeler before that, were the best venues for capturing snapshots of the status quo of the day. Still, many things never
change, so much of the old content is relevant to today's modeler.
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Symposium on Free Flight Adjustment Part II
Here are more contest-winning design and adjustment secrets revealed by some of America's top free flight champions. These came in response to a special survey made by American Modeler magazine. See our January 1957 issue (pages 16, 17 and 18) for background information on this cross-country check.
Additional construction details, and complete data on power plants, plugs, fuels, etc., on many of the following flyers' National contest-winning model aircraft will be found in the special section "Analyses of National Modelplane Winners - United States Aero Championships of 1956" in the 1957 Edition of Air Trail Model Annual.
This Long Beach, Cal., flyer won first place in Class B Open at 1956 Nationals with time of 28:35.1. Says all his models are alike, 2 deg. difference "in wing and stab and 8 deg. down-thrust. Uses left rudder and stab tilt for glide. Hand glides to determine proper incidence, and likes a very slight left turn. Changes both wing and stab incidence to correct glide but if it takes too much or affects power, adds weight. Uses 2 or 3 sec. engine run on Half A models, 5 or 6 sec. on all others for initial test flights. Slightly rich mixture and plugged intake when possible. Alters thrust to correct severe turn, corrects loops and wing overs with downthrust. Prefers to stick to one size prop for each engine. Has tried changing pitch but reports it doesn't affect his models enough to warrant its use. Flys right-left flight pattern but if warped properly left-left pattern. Believes adjustment is more important if you have good basic design. If design is bad to start with you have troubles. Recommends medium height pylon models as easiest for beginners to adjust. Advises beginners not to try to obtain a perfect power pattern by cutting down on incidence. Use down thrust if necessary. Admits he has been using it lately and finds climb is just as good and recovery is better with enough incidence. Also finds this set-up gives getter glide, more stability. Would advise novice building Half-A model and fly in grassy field. Then vary all adjustments to find out what happens when you do.
Although he resides in Los Angeles, Gene, 15, flys as member of Long Beach Thunderbugs. In junior events at last National meet, he won 1st Class A free flight, seconds in A/2 and B, third in C! Says Gene, "The fellow who is responsible for me being a good flyer is Harry C. Gould who really is a modeler's friend along with the rest of the Thunderbugs." Flies modified "Sailplanes" with 1/8" positive wing incidence, about 5 deg. down thrust. Adds 1/2 ounce weight to tail. Flies to left under power by washing-in left wing panel. Tilts stab, also shifts stab to give wide left glide turn. Builds stab as light as possible. In this way can add weight in stab if necessary to trim glide. Alters stab incidence if needed. Claims incidence changes to stab are more effective. Test flies with 10 to 15 second motor run with half power and prop on forward. Uses fairly heavy prop that gives considerable left torque. Believes good design is very important, adjustment know-how is also important. Recommends beginners use flat bottomed airfoil in wing. Says under-cambered sections are more difficult to adjust due to tendency to glide in tail-high attitude.
S/Sgt Fred W. Salmon
Stationed at Whiteman, Mo., AFB, flew as member of Air Force team at 1956 Nationals taking first in Half-A free flight open with 14:29.6. Uses 2 deg. positive incidence in wing, zero degrees in stab; 6 deg. downthrust and 3 deg. left on motor. Believes in hand gliding; strives for very gentle right turn, achieves by tilting stab. Except for experimental models, C.G. location should not be changed. Makes trim adjustments to stab. Test flies with 5 to 10 sec. motor run and right-right pattern. Runs engine just above idle with prop on forward. Says prop on backward does not present a true picture of what can be expected. Claims even changing brands of props can spin in a model. Never changes pitch to alter turn. Considers adjustment just as important as good design. Recommends Half-A to beginners. Feels they will take more punishment than larger models.
Oildale, Cal., competitor took first in Class C senior flying at '56 Nats with 16:25. Uses 5/8" positive incidence on wing of his "Ramrod." Zero stab setting. Uses downthrust but tries to stay away from side thrust. Hand glides and adjusts for slight stall during first flights. Tilts stab 3/16" and flies in right-left pattern. Uses fuse type dethermalizer on all flights. Adds weight to nose on fourth test flight to offset extra weight of longer dethermalizer fuse. Recommends a 12 sec. engine run on 1/2 to 3/4. power to allow model to gain about 200 feet altitude. In case of severe stall, this gives dethermalizer chance to pop. Feels propeller plays an important part in final flight pattern and changes pitch to alter power turn. Believes no model is hard to adjust if you know what you are doing.
Nineteen year old Meriden, Conn., free flight fan scored 14:45 in Class B contest at National championships, taking first. Flies with 3/16" positive wing incidence, zero stab setting. Never uses side thrust but on models that loop recommends some downthrust. Hand glides for left turn with nose slightly high. Gets desired glide left turn with rudder and tilting stab. Corrects glide angle by altering incidence to both wing and stab. Adds weight only if absolutely necessary. First test flights made with 8 to 10 second motor run at slow speed and prop on backwards to cut down torque. Flies both a right-left and right-right pattern depending on type of model. Believes adjustment know-how more important than design.
Duncan, Okla., Balsa Bugs member was best senior flyer in Half-A free flight at '56 Nats. He works as a machinist. Uses 3/8 to 3/16" positive wing incidence. zero stab setting; 7 to 8 deg. downthrust and slight left thrust. Controls glide turn with tilting stab. Hand glides but does not trim for turn. Prefers glide to left but says it doesn't make much difference whether it's left or right as long as transition from power is smooth and without spinning tendencies. Does not use rudder tab. If tilting tab is insufficient, warps wing. Corrects glide by changing wing incidence. Alters stab if necessary. Says weight should only be added when model is very nose or tail heavy. Test flies with 5 second motor run. Low power prop on forward. Recommends a 6-3 or 6-4 prop for 1/2A models. Believes adjustment and design equally important. Claims hardest models to adjust are those with no incidence in wing and stab and C. G. at wing trailing edge.
Lawrence H. Conover
This Cedar Rapids, Iowa designer has produced numerous models in all types of contest events. A member of America's 1956 International F.A.I. team, his model was proxy-flown in England to second place. Flies with 2 deg. positive wing incidence, 2 deg. negative stab setting, engine thrust 3 deg. left and 3 deg. down. Hand glides and flies models in right, right pattern. Uses tilted stab and washes in wing on inside of turn. Rudder tab for power turn only. Claims decalage determines power characteristics, says glide can be trimmed by adding weight. Also makes incidence changes to either wing or stab depending on conditions. Test flies with 5 to 8 sec. motor run at lowest power with intake plugged and prop on backwards. Feels prop is important and changes to a lower pitch if model flies too fast and is hard to handle. Likes right corkscrew climb at 70 deg. angle, flying up on wing. Believes you can make anything fly, most efficient setup is to design for specific set of conditions. Claims low powered and slow moving models win more consistently. Recommends beginners take it easy and make only small adjustments to control surfaces at one time. Rudder is very critical. Keep a log book with adjustment information on all your models. Always use a dethermalizer; think before you fly.
This Des Moines, Iowa, modeler, only 17, has racked up a tremendous record in National meet flying: he has participated in every Nats since '48 winning 4 firsts, 2 seconds and a third place. At the '56 championships in Dallas he did 13:59.8 in Class A F/F senior to take first. Flies "Spacer" with 3 deg. positive wing incidence, stab at zero. Uses small rudder tab rather than thrust adjustments. Says this method is not as critical under power. Tilts stab for glide turn. Hand glides for floating right turn. Prefers adding weight to changing incidence angles. Initial test flights made with 7 second motor run, rich fuel mixture and propeller on backwards. Does not change prop pitch to alter power turn. Follows engine manufacturer's prop specs. Flies right-right pattern on high pylon models, but flies low pylon types to the left. Believes adjustments know-how very important. Suggests beginners to F. F. gas start out by building contest type kits of proven design. Build original designs after winning a few contests. Claims if you can't adjust someone else's design, you won't be able to adjust your own design.
Dennis W. Alford
Resides in San Diego, is member of E; Cajon Modelairs and one of West Coast's outstanding junior (14 years old) competitors. At last Nationals Dennis won firsts in B, C and ROW free flight! Usually flies "Sandy Hogan" with 3/8 inch positive wing incidence; zero stab. setting; 2·to 3 deg. right and downthrust. However says these adjustments do not hold true under all conditions. At '56 Nationals used 1/2" positive wing incidence, 1/16" negative stab. setting, 2 deg. right thrust and 3 deg. downthrust. For glide turn tilted stab 2 deg. and offset rudder tab 2 to 3 deg. Also recommends floating tab on left wing at polyhedral. Hand glides after model balances correctly and permanent weight has been added. Corrects glide angle with wing incidence and stab if necessary. Test flies with no more than 10 sec. motor run with venturi half plugged, rich mixture and prop on forward. Makes adjustments as power is increased to keep model in right turn and climbing at a 70 deg. angle. Believes prop plays an important part in final flight pattern; sticks to same prop. Claims design and adjustment of equal importance. Uses silk covering on all but 1/2A models. Says extra strength and long life worth extra cost. Advises beginners to build Class B or C model and use Class A motor. Believes downfall of most beginners is too much power.
J. R. Hayden, Jr.
San Antonio Gas Model Association member Hayden was top man in Class A free flight (adult division) at last Nationals with time of 17:08. Builds pylon type models with 2 deg. downthrust. Achieves proper glide angle by altering incidence angles in both wing and stab. Says sometimes addition of a little nose weight plus added positive wing incidence will increase penetration. Flies right-left pattern. Prefers tilting stab to control glide turn but also favors use of floating wing tab. Makes test flights on 8 second motor run at 1/3 power and prop on backwards if highly powered model. Claims with some models, changing from 4 to 5" pitch propeller may give better power pattern and more altitude even though engine will not rev as high.
One of America's top-notch flyers, this Passaic, N. J., modeler was member of 1955 and 1956 U.S.A. International F.A.I. free flight teams, also won a position on America's '56 Nordic glider squad! Model shown flies with 5 deg. positive wing incidence, 3 deg. positive in stab. No thrust adjustments but may use 1 or 2 deg. right thrust to give right spiral climb. Hand glides for left turn but says this only determines how good glide is and should be used only as rough estimate. Prefers tilting stab for glide turn. Adds weight to nose of fuselage or builds lighter stab to correct glide angle. Flies right-left pattern and uses rudder tab for final power turn adjustment. Test flies on about 7 second motor run with rich mixture. If pattern looks good makes all further tests with full power. Agrees prop pitch affects climb turn but favors prop that gives maximum thrust. Believes for all-out consistent performance superior design is necessary but proper adjustment is needed to bring out design's potential. Favors rudders anchored to fuselage instead of to stab. Claims high aspect ratio wings (12 to 1 or higher) give real boost to glide on Class A or larger models but ability to roll and thus keep nose up in spiral climb is impaired. Cautions beginners against starting with shoulder wing jobs, claims these models require real mastery of rifling tendencies. Says high pylons with moderate aspect ratio and plenty of dihedral are easiest to adjust.