General control line discussion > Open Forum
Electric Twister comes in when turning and Timer set up???
Paul Taylor:
Hey Guys, need a little help.
I built a Electric Twister and in the process of setting it up.
Setup is a Hubin Timer, BA ESC, Cobra motor.
I had to change the program on the timer to Throttle mode because it would not allow me to adjust the RPM. Is that the correct selection?
The plane flys good in level flight and when the motor quits it glides in with little handle input.
When in flight I turned it over to inverted flight and it seem to come in and get light on the lines. Then when turning it back over to up right flight it really came in and went into free flight.
What are some things to check?
Thanks
gene poremba:
Paul, I'd look to see that one side of your elevator and or your flaps are not tweaked more than the other side. Look at the model from the tail end at a slight distance and eyeball the elevators and flaps to see that they are on the same plane. You should be able to see any warp in the wings also......Gene
Brett Buck:
--- Quote from: Paul Taylor on June 13, 2022, 10:22:35 AM ---
The plane flys good in level flight and when the motor quits it glides in with little handle input.
When in flight I turned it over to inverted flight and it seem to come in and get light on the lines. Then when turning it back over to up right flight it really came in and went into free flight.
What are some things to check?
Thanks
--- End quote ---
Check for a warp, and whether or not the wings are level upright and inverted. Even if you don't find a warp, adjust it until the line tension is equal upright and inverted. I presume that the hinge line is already sealed, if not, seal the hinge lines and start over.
Other possibilities include stab tilt.
Brett
Tim Wescott:
I need to make a video on how to do this...
Put the spinner on your toe, close one eye, and sight down the fuselage. Tilt the plane in pitch until you see equal amounts of wing above and below the trailing edge (move the flaps as necessary so you can see).
Now, without moving the position of the plane or your head, slide your line of sight to each wing tip. You should see equal amounts of wing above and below the trailing edge. If you don't the wing is twisted and you need to fix it.
While you're doing that, check to see whether or not the flaps are lined up with each other. If they aren't, and the wings are straight, then the flaps need to be tweaked (after you fly it, the flaps should be tweaked to where they need to be, but more than a 1/4" difference between them and the plane flying pretty good means that something is warped).
Now tilt the plane in pitch until the vertical stab is visually just touching the wing. On a Twister, the bottom of the stab should look exactly parallel to the wing (on a wing with taper, the stab should be spaced equally at the tips). If there's visible stab tilt, you need to fix it. While you're looking, make sure the elevators are lined up with each other -- if they're tweaked, you want to un-tweak them.
Finally, measure the length of each stab from the fuse center to the tip, to make sure you centered the stab. These should be equal to within 1/16". If you did, measure each rear tip of the stab to the back of the canopy at the center of the fuselage. These should be equal to within 1/16".
If anything looks wrong report back -- we'll tell you how to fix it.
Ken Culbertson:
--- Quote from: Paul Taylor on June 13, 2022, 10:22:35 AM ---Hey Guys, need a little help.
I built a Electric Twister and in the process of setting it up.
Setup is a Hubin Timer, BA ESC, Cobra motor.
I had to change the program on the timer to Throttle mode because it would not allow me to adjust the RPM. Is that the correct selection?
The plane flys good in level flight and when the motor quits it glides in with little handle input.
When in flight I turned it over to inverted flight and it seem to come in and get light on the lines. Then when turning it back over to up right flight it really came in and went into free flight.
What are some things to check?
Thanks
--- End quote ---
On the timer, I have never used a BA ESC, however, I do not think that Throttle mode is correct. When the motor looses RPMs in any kind of maneuver it should recover immediately. You should be feeling an RPM "bump" coming out of something as simple as flipping the plane over. Anything else you do to correct this will be a waste of time until you get the timer/esc right.
Back to aerodynamic reasons for the problem other that what Brett, and now Tim, posted which will be the primary cause. One I have encountered was a weak flap horn being driven by a bolt on horn on the outboard wing. All of the control force went to the outboard flap and they did not move equally under load. Same would apply to the Elevator. Next comes tip weight. I flew an F-Twister as my Profile in competition and practice plane off season for two years. It needs enough tip weight. Mine also liked being a bit nose heavy. Here is where I get slapped upside the head by the no rudder crowd. Mine never flew very well over 45 until I gave it 1/4" of rudder offset. Maybe it was trying to hold on to it's roots LL~
Ken
Oh, one more. Take a look at the line rake. If it is excessive, you may be flying nose in already.
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