Variable TI effect?
10-21-2007 | 11:50 AM
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From: Navarre,
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Variable TI effect?
Greetings,
I think I found the answer for why I couldn't get my DF to come back upwind to me a week or so ago. I was using full stick, and it just wouldn't bank more than maybe 10-20 degrees. Yaw worked fine, but nick and roll just wouldn't bank the DF enough to come back.
The answer is that TI doesn't always work the same from one cal to another (same day, same location, etc). Mike is the one who made me think about this again, because he mentioned that it seemed to calibrate better if you hold the arm button for 2-3 seconds, rather than just punching it quickly as I always do. He even said he thought he saw that in the instructions somewhere, but it sure isn't in mine, and it isn't in the on-line manuals at DFI.
This morning was a little windy, but without a cloud in the sky, so I did a test. I took the same DF (large frame BL mod) out in the yard, did my normal cal by punching the button quickly, and flew it a bit. This was all quite normal, with plenty of bank authority. Next, I tried it again, but this time holding the arm button for 3 seconds. It was like night and day! The DF was fighting me to stay level, exactly like it was doing the day I had to ditch downwind. I've always wondered why people complained that the DF wasn't responsive enough with TI enabled, but now I see why.
Just to confuse the issue, I went back out, and tried to repeat the test. This time, holding the arm button didn't make it behave any differently than just punching it quickly. Also, neither of these flights had the fierce TI leveling effect that I had on the earlier flight. Now I'm back to not being sure why it sometimes is more effective than others.
FWIW, in every test, I held the DF in the same location in the yard, and pointed the horizontal arms the same direction. Conditions didn't change significantly between test either. If I had to guess, I'd say that I've seen the excess TI effect about 5% of the time on average. Has anyone else noticed this?
Cheers,
Rusty
I think I found the answer for why I couldn't get my DF to come back upwind to me a week or so ago. I was using full stick, and it just wouldn't bank more than maybe 10-20 degrees. Yaw worked fine, but nick and roll just wouldn't bank the DF enough to come back.
The answer is that TI doesn't always work the same from one cal to another (same day, same location, etc). Mike is the one who made me think about this again, because he mentioned that it seemed to calibrate better if you hold the arm button for 2-3 seconds, rather than just punching it quickly as I always do. He even said he thought he saw that in the instructions somewhere, but it sure isn't in mine, and it isn't in the on-line manuals at DFI.
This morning was a little windy, but without a cloud in the sky, so I did a test. I took the same DF (large frame BL mod) out in the yard, did my normal cal by punching the button quickly, and flew it a bit. This was all quite normal, with plenty of bank authority. Next, I tried it again, but this time holding the arm button for 3 seconds. It was like night and day! The DF was fighting me to stay level, exactly like it was doing the day I had to ditch downwind. I've always wondered why people complained that the DF wasn't responsive enough with TI enabled, but now I see why.
Just to confuse the issue, I went back out, and tried to repeat the test. This time, holding the arm button didn't make it behave any differently than just punching it quickly. Also, neither of these flights had the fierce TI leveling effect that I had on the earlier flight. Now I'm back to not being sure why it sometimes is more effective than others.
FWIW, in every test, I held the DF in the same location in the yard, and pointed the horizontal arms the same direction. Conditions didn't change significantly between test either. If I had to guess, I'd say that I've seen the excess TI effect about 5% of the time on average. Has anyone else noticed this?
Cheers,
Rusty
10-21-2007 | 12:33 PM
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From: petah tikva, ISRAEL
RE: Variable TI effect?
Hi Rusty
That what I did all the time but the Ti did not behave correct,until i found the CH5 switch was in Of condition when I made the Ti calibration . when I turn to on and make the calibration TI work OK i think that the reason is that the DF board have to recognize CH5 so it must be in on position.
BTW I want to shorten my large frame from 70 cm to???? Because{as i told you before) gyro did hold the DF The one milion $ question WHAT IS THE EVERAGE SIZE.
Moti
That what I did all the time but the Ti did not behave correct,until i found the CH5 switch was in Of condition when I made the Ti calibration . when I turn to on and make the calibration TI work OK i think that the reason is that the DF board have to recognize CH5 so it must be in on position.
BTW I want to shorten my large frame from 70 cm to???? Because{as i told you before) gyro did hold the DF The one milion $ question WHAT IS THE EVERAGE SIZE.
Moti
10-21-2007 | 01:42 PM
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From: Navarre,
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RE: Variable TI effect?
Hi Moti,
Well, if the question was really worth a million dollars, I'd be a lot more motivated to find an answer
Seriously, I'm not sure anyone can answer the question about frame size without a lot of tedious experimentation. Even then, if TI doesn't calibrate the same every time, then there's never going to be one right answer for that part of the equation.
Since Mad Scientist Mike has hinted that he's working on a variable gyro gain project, and hopes to make an announcement this coming week, you might still want to sit tight and see what sort of diabolical project he's come up with
Rusty
Well, if the question was really worth a million dollars, I'd be a lot more motivated to find an answer
Seriously, I'm not sure anyone can answer the question about frame size without a lot of tedious experimentation. Even then, if TI doesn't calibrate the same every time, then there's never going to be one right answer for that part of the equation.
Since Mad Scientist Mike has hinted that he's working on a variable gyro gain project, and hopes to make an announcement this coming week, you might still want to sit tight and see what sort of diabolical project he's come up with
Rusty
10-21-2007 | 03:25 PM
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From: Huntertown, IN
RE: Variable TI effect?
ORIGINAL: 13BRV3
Hi Moti,
Well, if the question was really worth a million dollars, I'd be a lot more motivated to find an answer
Seriously, I'm not sure anyone can answer the question about frame size without a lot of tedious experimentation. Even then, if TI doesn't calibrate the same every time, then there's never going to be one right answer for that part of the equation.
Since Mad Scientist Mike has hinted that he's working on a variable gyro gain project, and hopes to make an announcement this coming week, you might still want to sit tight and see what sort of diabolical project he's come up with
Rusty
Hi Moti,
Well, if the question was really worth a million dollars, I'd be a lot more motivated to find an answer
Seriously, I'm not sure anyone can answer the question about frame size without a lot of tedious experimentation. Even then, if TI doesn't calibrate the same every time, then there's never going to be one right answer for that part of the equation.
Since Mad Scientist Mike has hinted that he's working on a variable gyro gain project, and hopes to make an announcement this coming week, you might still want to sit tight and see what sort of diabolical project he's come up with
Rusty
Rusty, do you think your erratic TI might be due to the receiver conversion you are using? Maybe the timing for channel 5 is different enough that it is not activating TI every time. As we discussed, TI is working perfect for me now that I am careful to always hold the arm button down for several seconds. Of course, all my DFs are now using the variable control on channel 6 so that is one thing that is different.
Mike
10-21-2007 | 07:56 PM
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From: Navarre,
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RE: Variable TI effect?
ORIGINAL: Old Man Mike
Rusty, do you think your erratic TI might be due to the receiver conversion you are using? Maybe the timing for channel 5 is different enough that it is not activating TI every time. As we discussed, TI is working perfect for me now that I am careful to always hold the arm button down for several seconds.
Rusty, do you think your erratic TI might be due to the receiver conversion you are using? Maybe the timing for channel 5 is different enough that it is not activating TI every time. As we discussed, TI is working perfect for me now that I am careful to always hold the arm button down for several seconds.
I was wondering if TI wasn't being set at all, but I turned channel 5 off, and tried it. Trust me, TI was on before
My assumption is that channel 5 is treated as a switch only, and the exact pulse width has no significance to TI function or calibration. If that's not true, then maybe I could tweak the end point adjustment for channel 5 and make a difference. If I run out of other things to do (not likely), I could put the hacked Berg receiver on it, and try flying it with the original DF transmitter.
Rusty
