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Hey Bart, As Ivan has drawn the 'leading edge cuff' on the Solent, it's really not one at all. A leading edge cuff can serve two purposes. First, the droop in the leading edge reduces the onset of a stall. The second is that when the leading edge cuff is 'exposed' out on the leading edge, it can create a vortex which can increase the effectiveness of the aileron at slow speed when the wing is approaching a stall. Simply 'extending' the leading edge the way Ivan has done it only has the effect of increasing the wing area.
http://en.wikipedia.org/wiki/Leading_edge_cuff -Zeke |
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Hi Bart
I saw that nice video in post #1. That is a real nice piece of historical footage. Now I have a technical question for you and some of your following patron fliers. Watching the motors running in the videos brought this back to my chain of thoughts an the ways of applying this to model aircraft. I have left and right rotation matched propellors on my Martin Mars and Kawanishi Emily. This has kept me thinking many a night about this in my pre-sleep bedtime dreams. What do you or others reading this think of the most effective way to use 2 motors going opposite the other 2 motors. When you think of it. There are 4 ways these motors can be set up turning inboard or outboard or a pair turning away or toward themselves. You can also have the port motors turning outward and the starboard going outward or vice versa. These effects can mean something if there is an engine loss. It can also mean throwing water spray toward the fuselage or away. It may also effect the output efficiancy thrust. There are so many things to account for here in chains of thought. It may have to probably be a flight engineer or a 4 motor pilot to understand motor rotations and applications to various aircraft. The only plane I read trials with this was the P-38 Lightning on torque problems and loss of a motor.with the effects on handling. This may be a long shot asking this brain teaser in this thread. I just never found much on the subject that puzzles me. Thanks, **Neons** Bob |
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I have my motors all swinging the same direction and i had no ail or rudder trim needed at all on its first flight ,it also showed no tork effect on the water . AS far as counter rotating props helping keep water away from the fuse and the effect on the tail surface your guess is as good as mine . I know my wing is at 5 pos and my motor;s are at one neg and it works just fine except for some down trim to get her to fly level ,but she leaps of the water very well . joe
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Multi engine torque/airflow
With a lot of multi engine a/c (~especially military) the negines run the same way (though this is for spares reasons, and none other).
With large torquey engines, it makes sense to have them 'paired' so that opposite sides drive opposite rotations, to cancel the torque reaction. (a good example of this not happening is the jetstream light commuter turboprop- this a/c is not allowed to stall (stick pusher activates at +5-10 knots) as the engine torque (both running same way) is known (test flight) to cause a serious spin!) The new A400M has paired engine rotations designed to optimize airflow over the centre wing sections, and tailplane. However it should be noted- this caused issues with the parachutists.... ![]() For the scale we operate at, the main effect is likely to be torque reaction (unless properly side and down thrusted) as the mass air flow rates we shift (unless your model is capable of prophanging) are rather too low to have any majorly appreciable effects Scott MEng Aeronautics and Astronautics |
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Quote:
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@ Scott , thanks for the explanation !!
Went on with the wing , nacelles an cowlings. Tommorow i have to make the former for the aileron servo. And the i can do the fun part , set the wing to the correct dihedral and mirrr the whole construction. And then of course make a 2d plan and sort al the parts to sheets . . . . . and. . i almost forgot : i have to work . . . thats ok but itcost so much free time. Cheers, Bart |
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Thanks Scott,
I was just giing though on the best combo. I did see that the Avro Lancasters use 2 opposed engines on each wing with there Rolls Royce motors. I have them on my Hu-16 Albatross and she tracks straight on the water and in the air too. Nice work, Bart. Just love looking at it. **Neons** Bob |
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