airspeed activated function
11-15-2018, 04:08 PM
#5
I can't answer your question about a sensor but there is no way I would set a function like wing swing to happen automatically. That just sounds like a disaster waiting to happen. Judging airspeed is difficult and even with telemetry telling you the speed it's not like speeding up or slowing down is instant. Imagine coming off the bottom of a loop and airspeed all of a sudden says swing the wings. Now maybe you're too close to the ground to pull out with the wings back or on the way.
Besides that in every video of F14's I have watched nobody keeps the wings swept for long. I've never flown one but it appears that perhaps they are much more of a handful with the wings swept than when extended. Just seems like a bad idea to me.
your mileage may vary.
Besides that in every video of F14's I have watched nobody keeps the wings swept for long. I've never flown one but it appears that perhaps they are much more of a handful with the wings swept than when extended. Just seems like a bad idea to me.
your mileage may vary.
11-15-2018, 10:20 PM
#6
That switch not only swept the wings, it engaged a special flight mode disabling the spoilers, increasing gyro gain and increasing taileron movement...
David
11-15-2018, 11:42 PM
#7
11-16-2018, 07:09 AM
#8
Hi Guys,
Interesting discussion. As a long-time Futaba user, I can confirm that there is no way to use telemetry values to activate any actions in the TX. Perhaps others can comment on any other brands that can or can't do this.
As has already been pointed out, Jeti systems can do that, you can create a "virtual channel" (they call them telemetry controls) driven by a telemetry value that can be included in TX functions such as mixers, switches, etc and could in principle do what you are wanting to do. I don't know if the new Powerbox radio can do that, if anyone knows that would be an interesting data point to have.
Though I have never had any issues with link reliability with Futaba, I was frustrated with their total lack of innovation, and have switched about half of my planes to Jeti. One of the main reasons was what you could do with their telemetry, and this is a good example of the sort of problem that drove my switching. And LA Jetguy already has been flying the swing-wing function!
Having spent the summer with the Jeti radio, and looking at a lot of logs of telemetry data from actual flights at many different fields, I would offer one small caution. There are "gaps" in the telemetry data that comes down to the TX during the flight. You can see them clearly in the log files. Maybe 1-3 second gaps 5-6 times during a flight where there is no telemetry data on some telemetry values. Maybe due to antenna orientation, but no way to be sure what the actual cause might be. Jeti I think knows this happens (they seem to be very good engineers), and has included some functionality in the TX that mitigates the impact for these gaps. For example, (see page 112 in the DX manual) you can set up filtering, and account for occasionally missing data in the telemetry by only responding to triggers after so many seconds etc. For example I implemented a TX-based pneumatic gear failsafe using telemetry control from the air pressure sensor and used the feature so that the gear would only go down after low air pressure was reported for more than 5 seconds. So a 1-3 second gap in air pressure data would not drop the gear. The tradeoff is a 5-second delay in responding to a leak. No free lunch :-)
So while it is quite rational to worry about coupling critical flight controls to telemetry, your case might fit into the "doable" category. The delay you can set (e.g. only sweep the wing forward if the airspeed is less than 80 mph for 5-10 seconds .. only sweep the wing back if the airspeed is greater than 100 mph for 5-10 seconds) would give you some hysteresis. Then the wing would not be sweeping back and forth willy-nilly. I suspect that would work and would be relatively safe. For further safety you could have a 3-pos switch .. one end is wing forward, other end is wing back .. middle is "automatic" based on airspeed. So no matter what happens you can failsafe to a known configuration. At least that's what I'd do... and David did a similar thing in his setup.
You would want to stare at a bunch of telemetry log data and make up your own mind of course... you're the only one who can decide for your plane what level of function and "coolness" is worth what level of risk.
Dave
Interesting discussion. As a long-time Futaba user, I can confirm that there is no way to use telemetry values to activate any actions in the TX. Perhaps others can comment on any other brands that can or can't do this.
As has already been pointed out, Jeti systems can do that, you can create a "virtual channel" (they call them telemetry controls) driven by a telemetry value that can be included in TX functions such as mixers, switches, etc and could in principle do what you are wanting to do. I don't know if the new Powerbox radio can do that, if anyone knows that would be an interesting data point to have.
Though I have never had any issues with link reliability with Futaba, I was frustrated with their total lack of innovation, and have switched about half of my planes to Jeti. One of the main reasons was what you could do with their telemetry, and this is a good example of the sort of problem that drove my switching. And LA Jetguy already has been flying the swing-wing function!
Having spent the summer with the Jeti radio, and looking at a lot of logs of telemetry data from actual flights at many different fields, I would offer one small caution. There are "gaps" in the telemetry data that comes down to the TX during the flight. You can see them clearly in the log files. Maybe 1-3 second gaps 5-6 times during a flight where there is no telemetry data on some telemetry values. Maybe due to antenna orientation, but no way to be sure what the actual cause might be. Jeti I think knows this happens (they seem to be very good engineers), and has included some functionality in the TX that mitigates the impact for these gaps. For example, (see page 112 in the DX manual) you can set up filtering, and account for occasionally missing data in the telemetry by only responding to triggers after so many seconds etc. For example I implemented a TX-based pneumatic gear failsafe using telemetry control from the air pressure sensor and used the feature so that the gear would only go down after low air pressure was reported for more than 5 seconds. So a 1-3 second gap in air pressure data would not drop the gear. The tradeoff is a 5-second delay in responding to a leak. No free lunch :-)
So while it is quite rational to worry about coupling critical flight controls to telemetry, your case might fit into the "doable" category. The delay you can set (e.g. only sweep the wing forward if the airspeed is less than 80 mph for 5-10 seconds .. only sweep the wing back if the airspeed is greater than 100 mph for 5-10 seconds) would give you some hysteresis. Then the wing would not be sweeping back and forth willy-nilly. I suspect that would work and would be relatively safe. For further safety you could have a 3-pos switch .. one end is wing forward, other end is wing back .. middle is "automatic" based on airspeed. So no matter what happens you can failsafe to a known configuration. At least that's what I'd do... and David did a similar thing in his setup.
You would want to stare at a bunch of telemetry log data and make up your own mind of course... you're the only one who can decide for your plane what level of function and "coolness" is worth what level of risk.
Dave
Last edited by ww2birds; 11-16-2018 at 07:15 AM.
11-16-2018, 05:27 PM
#11
Danny
[email protected]
407-687-3126
11-17-2018, 02:42 PM
#14
I can't answer your question about a sensor but there is no way I would set a function like wing swing to happen automatically. That just sounds like a disaster waiting to happen. Judging airspeed is difficult and even with telemetry telling you the speed it's not like speeding up or slowing down is instant. Imagine coming off the bottom of a loop and airspeed all of a sudden says swing the wings. Now maybe you're too close to the ground to pull out with the wings back or on the way.
Besides that in every video of F14's I have watched nobody keeps the wings swept for long. I've never flown one but it appears that perhaps they are much more of a handful with the wings swept than when extended. Just seems like a bad idea to me.
your mileage may vary.
Besides that in every video of F14's I have watched nobody keeps the wings swept for long. I've never flown one but it appears that perhaps they are much more of a handful with the wings swept than when extended. Just seems like a bad idea to me.
your mileage may vary.
There are numerous considerations when programming that model such as making the flaps retract if you start moving the wings back. Eliminating the spoilers (it doesn't have ailerons or at least my Skymaster F14 does not), whether or not you want the leading edges deployed or retracted, a substantial decrease in the elevons deflection and expo. Long story short; it took all 18 channels of a Futaba 18MZ to cover everything and that does not include a speed related automatic actuation of the wing sweep.....
11-17-2018, 03:47 PM
#15
I concur; there's no way I'd set up something like that on my F14 and I've not even flown it yet....
There are numerous considerations when programming that model such as making the flaps retract if you start moving the wings back. Eliminating the spoilers (it doesn't have ailerons or at least my Skymaster F14 does not), whether or not you want the leading edges deployed or retracted, a substantial decrease in the elevons deflection and expo. Long story short; it took all 18 channels of a Futaba 18MZ to cover everything and that does not include a speed related automatic actuation of the wing sweep.....
There are numerous considerations when programming that model such as making the flaps retract if you start moving the wings back. Eliminating the spoilers (it doesn't have ailerons or at least my Skymaster F14 does not), whether or not you want the leading edges deployed or retracted, a substantial decrease in the elevons deflection and expo. Long story short; it took all 18 channels of a Futaba 18MZ to cover everything and that does not include a speed related automatic actuation of the wing sweep.....
11-18-2018, 04:13 PM
#24
Danny
11-18-2018, 05:26 PM
#25
Both the DS16 and DS24 are twenty four channels. As Danny said, the 24 offers a lot more and that 's saying something considering everything the 16 offers. Some is just bling and some are really cool useful features.