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Old Oct 10, 2012, 03:07 PM
austinhlg is offline
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United States, MD, Baltimore
Joined Feb 2007
891 Posts
OK first a disclaimer. I am not the highest launcher in the group but I am definitly in the top 1/4. This it the way I do it and have helped many sportsman gain 10-15 feet by 5 min of radio tuning using this technique.

1st off CG has nothing to do with launch. Set your cg by feel or dive test in cruise mode. After this is done you will need to set up your launch modes.

2nd "preset" lasts well less than 1 second and only is used to achive desired climb angle.

To explain, there are two different phases of launch that need their own radio programming.
Phase 1 (rotation) From when you start spinning through when you release and until the model has reached its optimum angle of ascent
Phase 2 (Zoom) ballistic part of launch after rotation until push over.

Phase 1 Mix will include:
1. UP elevator
2. (Speed mode) The cleanest air foil possible (this will vary depending on the model usually reflex or even with the tab)
3. Possible rudder correction however newer tail designs and proper technique eliminate this need.)
Phase 2 will include
1. (Speed mode)The same clean air foil as described in Phase 1 properly tuned with elevator compensation that will result in an arrow straight path after Phase 1 is complete.

To achive a well tuned speed mode you will utilize a "Dive test" after and independently of your "CG Dive Test" in this test you will set the camber to the cleanest air foil ie. speed mode and dive. Trim your elevator until the plane will folow a straight line all the way to the ground if you let it. The reason for this is that any change in pitch after your rotation is creating drag. You are only using the angle of attack to creat lift at this point and if the elevator is pitching the plane up you are losing speed for no reason.

You may chose to keep this as your only speed mode as I do. (It is a very high pilot work load at this trim setting used to creat speed then switch back to cruise) Or you may have a secondary trimmed for running home.

Once this speed mode is set up all you need to do is add a momentary switch with up elevator. The amount of up is personal preferance based on how fast you like you model to rotate. I have a very aggresive rotoation and have to get off the Phase 1 preset quickly.

The timing will take some getting used to but you will be able to adjust launch angle based on how long you hold the momentary switch.

G_Ts comment on airframe control while your other hand is busy is also crucial at times.

Hope this helps.
Austin
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