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JR 8103 Exponential Question

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Old 05-15-2003, 08:00 PM
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spinman
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Default JR 8103 Exponential Question

Has anyone noticed that the exponential graph is backward on the JR 8103 or am I reading it wrong. When I want a soft stick around neutral the graph should show low output on the Y axis. Mine shows high output at the start of stick deflection. Is this right or is it plotting backwards. This problem just about put one of my planes in the first time I flew with this radio. Luckily I had my where abouts to be able to land the plane with such touchy sticks. My knees were a knocking. I had about 50% expo dialed in.
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Old 05-15-2003, 08:15 PM
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CurtD
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Default JR 8103 Exponential Question

You are aware that JR expo numbers are reversed from Futaba, aren't you? A positive expo number on JR indicates less control movement near neutral (vs no expo) a negative number indicates more control movement near neutral. If you had 50% expo and the control was oversensitive check to be sure its a POSITIVE 50%, not negative. I like +25 to +35% expo on most of my planes.
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Old 05-15-2003, 11:50 PM
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spinman
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Default exponential problem

I didn't realize that Futaba and JR were different. I guess I should have double check this. I was looking at the graphical display and to me having a soft stick meant the display should show little output at the initiation of stick movement. The graph shows high output. The scale, no matter if the two radio's are reversed in positive and negative, should be able to be interpreted in the same way.
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Old 05-16-2003, 01:20 AM
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Ed_Moorman
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Default 8103 Exponential

I fly an 8103 and I agree, the graph has always looked 90 degrees out of phase to me. As an engineer, I am used to input (stick displacement) on the horizontal axis and output (control response) on the vertical. It always looks goofy to me to see the curve bulge the way it does.

Despite the backwards expo graph, the 8103 is a great radio. I just bought a second one, the Promo version with only the small 700, 7-channel, receiver, but 4 sport digital servos, all for $379. I wanted the digital servos and the price was right
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Old 05-16-2003, 10:43 AM
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spinman
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Default JR 8103 Exponential Question

I love the radio myself and got the promo price of $379 also. I just wanted to make sure that other radios showed the same type of response. Do you know what torque the digital servo's (811's) have.
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Old 05-16-2003, 01:24 PM
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Default JR 8103 Exponential Question

Spinman, looks like 54 oz in @ .18 sec / 4.8 volts. I have 3 that I have used in various planes. I think they have come up with a good cheap digital to replace standard servos with. Have not run any difinitive test, but it seems they are not that hard on battery life either.
You have a hard time finding the info on their website as they are not listed in the drop down menu's. Had to do a search for the info.
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