|Thrust, Weight & Wing Size||
Thrust: The force pushing you through the air, which is generated by the propeller. The thrust required for level flight is the amount required to overcome the total drag.
In comparison a heavier unit with a Total Drag of 34Kg needs to provide 9Kg more thrust to maintain level flight compared to a light unit with a total drag of 25Kg. Any "extra" thrust available will result in a climb.
"At the end of the day a pilot with lighter gear enjoys the same flight with all the advantages of carrying lighter equipment!"
Weight: As we have seen from the lift & Drag page, more weight requires both extra lift and thrust to maintain flight. Boeing and Airbus spend ever increasing budgets to reduce the weight of their aircraft. Extra weight decreases performance!
"More weight means more drag, which means burning more fuel for the same flight!"
Sink Rate: This is the vertical decent rate of the wing when it is allowed to glide with power off. It is closely connected to the L/D ratio and a wing with an L/D of 5:1 will have a Glide ratio of 5:1. So for every 5 metres the wing travels forward it descends 1 metre. A wing flying forward at 20mph will have a vertical speed (sink rate) of 4mph (20/5).
Wing Size: Selecting the correct wing is very important, too small and you will not be able to run fast enough to take off, too large and the wing will not perform efficiently and could easily be subject to collapses. To work out your total "take off weight" (Pilot, motor, fuel & wing) in Kg, add 35Kg to the pilot weight. Divide this weight by the wing area. We have found that a result between 4 and 4.5 should work well.