Flaps! What are they for? Very simply put they are used for three things: Take-offs, Landings, and Slow Flight.

As this Giant Scale movement gains momentum and more and more large, heavy WW II type models appear on the scene, the need to understand and use flaps is becoming of greater concern. In a nut shell and generally speaking... Flaps are used to lower the aircraft's stall-speed. That is, let it fly slower before it falls out of the sky and strikes terra-firma.

Flaps can also be used as an air brake if they are of the very large variety and are used in an extended at severe angles. When flaps are used in the extended mode of between 5 to 25 degrees they give the aircraft two aids for safe flight: 1) Increased lift at a slower airspeed without a significant increase in drag, and 2) They help induce a form of wash-out to the wing. This is seen in the center or inboard portion of the wing now has a relatively higher angle of attack in comparison with the section of the wings where the ailerons are. This feature helps prevent snap rolls at slow airspeeds. The wash-out effect alone should be enough to help convince all P-51, P-40 and similar type aircraft owners to use partial flaps during critical flight phases such as landings and take-offs. Flaps should be constructed in a similar fashion as the ailerons. However, it must be taken into account that the flaps generally have a greater area than ailerons and they will be required to support a greater portion of the aircraft's weight. This factor should determine the size, number and placement of the flap hinges. Always use two or three more hinges on each flap than what you think is really needed... Better safe than sorry!

Flaps are generally actuated in a number of fashions similar to the ailerons. Torque tubes are very popular and compact. If this method is used, be sure to use a torque tube of sufficient size and support it at each end as well as through each rib with adequate bearing blocks. Some modelers prefer the bellcrank and linkage system This also works very well. Again, always be sure to support all the linkage through each rib, etc. Regardless of the type of actuation system employed, it will always be best to set it up so that all linkages, etc. are in tension when the flaps are down. Remember that while in flight, the airstream will attempt to blow the flaps back up. It is this ease that we must design for.

On smaller aircraft one servo was used to actuate the flaps. Everything worked fine and dandy. On larger, heavier aircraft (approx. 20 Ibs. plus) it should be common sense to use one servo on each flap. After all you are probably using one servo on each aileron!

The use of flaps during take-off will really surprise the new user. The aircraft will become airborne sooner, feel more stable and will climb out better. Almost all by itself! After climb-out "slowly" raise the flaps as airspeed increases. Generally half to one-quarter flap deflection is used on WW II ships during take-off. Landings will be (or should be) nice and gentle, the flaps should he lowered during the down wind to base leg portion of your landing approach. The amount of deflection will be determined by wind speed and experience. Never lower the flaps at 1/4 to full speed. You may see them part company from the aircraft.

As the aircraft descends the throttle should be used to control the decent more so than the elevator. A little practice and you'll he amazed how slow and soft that lead sled WW II ship can fly. TRY 'EM - YOU'LL LIKE 'EM... Happy Landings.