Re: [Flightgear-devel] Re: Cockpit Hardware Building
Alan King writes: Rudder pedals. Been a while since I was at the controls in a Cessna etc, how much control throw is normal? With a one foot seperation between the pedals 4 seems like a lot, maybe too much. Currently have 2 in and 2 out for the 4 total, but can easily shorten it up, feels like I'd have a foot in the engine. I seem to recall that on a C172, the maximum rudder travel is about +/- 1.75 inches from the neutral point. Regards, Curt. -- Curtis Olson HumanFIRST Program FlightGear Project Twin Citiescurt 'at' me.umn.edu curt 'at' flightgear.org Minnesota http://www.flightgear.org/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
On 12:42 Thu 18 Dec , Alan King wrote: Rudder pedals. Been a while since I was at the controls in a Cessna etc, how much control throw is normal? With a one foot seperation between the pedals 4 seems like a lot, maybe too much. Currently have 2 in and 2 out for the 4 total, but can easily shorten it up, feels like I'd have a foot in the engine. That sounds about right for a 152. Maybe David can tell you how much throw is available on his aircraft? All the best, Matt. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
Matthew Law wrote: That sounds about right for a 152. Maybe David can tell you how much throw is available on his aircraft? This is going to sound stupid, but I'm not sure. I think of the rudder pedals in terms of pressure rather than movement -- to get that in a simulator cockpit, you'll need a servo motor attached. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
David Megginson wrote: Matthew Law wrote: That sounds about right for a 152. Maybe David can tell you how much throw is available on his aircraft? This is going to sound stupid, but I'm not sure. I think of the rudder pedals in terms of pressure rather than movement -- to get that in a simulator cockpit, you'll need a servo motor attached. Just a spring return to give some general feedback is all I'm planning for now. Main use on a simulator is simply to seperate the controls to the correct actions, don't see much point in going beyond that short of doing a full cockpit simulation of a particular type, which is beyond what I'm planning for the moment. I do motor controllers so it really wouldn't be much for me to do it, just don't see a whole lot of extra value beyond a spring for a basic control setup. Thanks guys for the info though, figured it was around +-2, just seems really far in doing it. But I've also kept the width a bit narrow at a little under a foot on the rails to save space, may be a bit closer than usual and make the throw seem longer. Still rather have close to right distance even then. Also I'm assuming the yoke on most planes has a bit more throw than +-2, but that's about the limit of what's practical with my current hardware so it'll probably do ok. I could get 6 travel or so max, just gets a bit more trouble to do. Alan ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
Alan King wrote: Just a spring return to give some general feedback is all I'm planning for now. Main use on a simulator is simply to seperate the controls to the correct actions, don't see much point in going beyond that short of doing a full cockpit simulation of a particular type, which is beyond what I'm planning for the moment. I do motor controllers so it really wouldn't be much for me to do it, just don't see a whole lot of extra value beyond a spring for a basic control setup. It depends on what you're doing. Control feedback is pretty critical for basic stick-and-rudder flying (that's one of the reasons that flying a plane in FlightGear is so much harder than in real life). For pure recreation, or for instrument training, it's not so critical. All the best, David ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
On 14:52 Thu 18 Dec , Alan King wrote: Also I'm assuming the yoke on most planes has a bit more throw than +-2, but that's about the limit of what's practical with my current hardware so it'll probably do ok. I could get 6 travel or so max, just gets a bit more trouble to do. It's 16-18cm from full down to full up elevator on the couple of C152's I've measured and roughly +-90 degrees of roll axis. BTW, I'm not anal. Honest! I'm just building a yoke of my own so I measured these recently. If you're in the right ball park for these figures IMHO you'll be just fine. As David quite rightly said, it's the feedback from the controls which varies according to many parameters that is by far the hardest thing to simulate. I'm going to use elastic cotton-covered 'bungee' cord to centre and resist on my yoke. Mainly because springs are quite difficult to come by and can be noisy to boot. All the best, Matthew ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
David Megginson wrote: Alan King wrote: It depends on what you're doing. Control feedback is pretty critical for basic stick-and-rudder flying (that's one of the reasons that flying a plane in FlightGear is so much harder than in real life). For pure recreation, or for instrument training, it's not so critical. Yes it is. But the control feedback in the simulator EXACTLY matching real life is not critical. For that matter a Cessna rudder probably doesn't exactly match a P-51 rudder either, but I have no doubts that learning rudder on said Cessna prepares you for 80 or 90 percent of how to use a P-51 rudder. Exact matches aren't critical, simply having some feedback and learning that you must pay attention to the feedback and develop a feel for what is right for a particular plane is most of it. With the sim plane being a bit different from the real plane, you're simply learning two different planes. It's still quite useful to have the basic feedback even if it's not exact. And I'm not aware of any even $10 mil simulators that are more than approximately real, even with a driven motor proper G forces have a noticable effect on your legs, yet are incompletely modeled. There's only so much you can effectively do without getting in a real plane, I'm just going for the basic 80 percent of it and leaving the other 5 or 10 percent that could possibly be done on the ground alone. It should still be quite effective for the cost. Later, Alan ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
Alan King writes: Yes it is. But the control feedback in the simulator EXACTLY matching real life is not critical. For that matter a Cessna rudder probably doesn't exactly match a P-51 rudder either, but I have no doubts that learning rudder on said Cessna prepares you for 80 or 90 percent of how to use a P-51 rudder. Exact matches aren't critical, simply having some feedback and learning that you must pay attention to the feedback and develop a feel for what is right for a particular plane is most of it. With the sim plane being a bit different from the real plane, you're simply learning two different planes. It's still quite useful to have the basic feedback even if it's not exact. And I'm not aware of any even $10 mil simulators that are more than approximately real, even with a driven motor proper G forces have a noticable effect on your legs, yet are incompletely modeled. There's only so much you can effectively do without getting in a real plane, I'm just going for the basic 80 percent of it and leaving the other 5 or 10 percent that could possibly be done on the ground alone. It should still be quite effective for the cost. The FAA defines tolerances that a sim builder needs to meet in order to be certified. Control forces are something they definitely pay attention to. Rudder force for some manuever might need to be within 5 lbs of the real thing for instance. But if it takes 4 lbs of force in the real airplane, that leaves you a bit of latitude. Regards, Curt. -- Curtis Olson HumanFIRST Program FlightGear Project Twin Citiescurt 'at' me.umn.edu curt 'at' flightgear.org Minnesota http://www.flightgear.org/~curt http://www.flightgear.org ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
Matthew Law wrote: On 14:52 Thu 18 Dec , Alan King wrote: Also I'm assuming the yoke on most planes has a bit more throw than +-2, but that's about the limit of what's practical with my current hardware so it'll probably do ok. I could get 6 travel or so max, just gets a bit more trouble to do. It's 16-18cm from full down to full up elevator on the couple of C152's I've measured and roughly +-90 degrees of roll axis. The 6 won't really be that hard to get, since that's closer may as well get it. I can do continuous roll axis with little trouble so the +-90 is easy enough. Actually takes a few extra parts to put in the stops. Rudder is the one that needs some serious stops though with your legs working against it. Feels good so far just have to link the pedals together now. BTW, I'm not anal. Honest! I'm just building a yoke of my own so I measured these recently. If you're in the right ball park for these figures IMHO you'll be just fine. As David quite rightly said, it's the feedback from the controls which varies according to many parameters that is by far the hardest thing to simulate. I'm going to use elastic cotton-covered 'bungee' cord to centre and resist on my yoke. Mainly because springs are quite difficult to come by and can be noisy to boot. Well the springs are plentiful enough at the local Ace, but do make a bit of noise. Won't matter much down at your feet on the rudder, but bungee may be the better choice, may need a pulley etc to shorten it up and keep it in my form factor for the yoke. I've got a thousand or two motors on hand of different types, so I could do some force. But my primary goal is to get control seperation and a general idea of feel, beyond a certain point it's simply more effective to stop simulating and hop in a plane to get the real feel. Plus it'll be better to keep it reasonably simple to build so most can get it done since I'm looking to put up plans. Later, Alan ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
Re: [Flightgear-devel] Re: Cockpit Hardware Building
Curtis L. Olson wrote: Alan King writes: The FAA defines tolerances that a sim builder needs to meet in order to be certified. Control forces are something they definitely pay attention to. Rudder force for some manuever might need to be within 5 lbs of the real thing for instance. But if it takes 4 lbs of force in the real airplane, that leaves you a bit of latitude. Well I wasn't really going for certification on my $30 homebuilt rudder and $30 yoke, although if there are specs and since I do motor controllers it might be worth looking at at a later date. But 5 lbs on the rudder when your leg weighs 30 lbs isn't nearly the same feeling as that same 5 lbs on the rudder when your leg weighs -30 lbs, and I'm not aware of too many sims that go inverted to do negative G's, though there are no doubt a few for military at least. But they're still useful even without doing everything perfectly. And a simple spring will still be useful, even if it has a few more trade offs and is less accurate a simulation than a motor system for more correct force, it's still much better than nothing, and has a significant chunk of the usefulness of a more complex system without the extra cost.. Time to go do the linkage, even without the pedals already feel pretty good. Alan ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
