zdy1004 wrote: ↑January 7th, 2022, 12:35 pm
Hey everyone!
I'm relatively new to Wright Stuff, and this is my first season competing, so I was just looking for some advice.
When trimming, I noticed that many of our flights ended with excess turns when the plane landed. We're using a 0.094 rubber (I think) and winding about 900-100 turns (60+ winds on a 15:1 winder.) How would I maximize the plane up-time (not waste winds)?
Any help is appreciated!
Welcome to Wright Stuff.
This is a key to tuning your setup, matching the rubber to the prop.
What are you considering "excess turns"? Typically, you will wind to near breaking, then back off to your launch torque, due to hysteresis in the rubber (you will get a lot more energy stored in the rubber by winding hard and then backing off). "Typically" the ideal balance will be when the turns remaining at landing equal the turns you backed off to get to your launch torque. If you are not measuring the winds remaining, do so (and record in your log).
If indeed there are a lot of turns remaining, this is an indication that your rubber is too thin for your prop and plane. To remedy this, go to thicker rubber, or reduce the pitch of your prop. Both of these will get closer to matching the prop and rubber. However, it may end up with a less than ideal situation. Reducing pitch of the prop brings it in line with the rubber, so that rubber is more optimized. However, the global optimum may actually be the higher pitch, with thicker (wider) rubber. That needs to be found experimentally.
I would try wider rubber first.
What is the pitch angle of your prop, measured with a pitch gage, typically at about 3/4 of the radius. We measure at 4" because that is one position on my pitch gage, others measure at 3" radius. You can then convert the pitch angle into pitch (pitch = ATN(Pitch_angle)*2*pi*radius_of_measurement). Typically you want to start around a pitch/diameter of 1.6 to 2.
Coach Chuck