IT'S ANOTHER GREAT month to be enjoying the sport of Radio Control (RC) helicopters! Almost everywhere in the country this is peak flying season. I hope you are all enjoying all the time you get to spend with this great sport and hobby. I've been getting many letters and E-mails lately. Thank you. My requests for input about what topics to cover got exactly the response I expected, and they were roughly evenly divided among "more flying stuff." "more setup stuff," and "more product stuff." I've been writing long enough to know that you can't please everyone with every column, so I'll keep trying to give some coverage to all three of those areas and a few other things as best I can. From all those I received, the following is an "average" letter from Dave Stafford. "I'm an avid reader of your column in MA and I noticed your request for input in the latest issue. Having started fixed wing RC back in 1970, I guess I could be classified as an old-timer, but my experience with RC helicopters only goes back five or six years. In that time, I've learned how to fly my entry-level Shuttle ZX in FF, nose-in hover, out-front 360s as well as stall turns (only about 60 degrees nose up, however), horizontal 8s, constant-rate descents to landing, etc. "Not all that long ago I would've been happy with those skills, but now I'm getting bored. I would like to improve my flying skills, but realize that I must master the proper setup of the so-called Idle Up modes before going much further. "I'm having a difficult time getting my radio programmed for Idle Up flying. I would prefer that there be no noticeable change when hitting the switch while in a hover. I've accomplished that part of the setup, but run into trouble in the realm of 0 degrees pitch and below. "The first time I used Idle Up I, the helicopter flew okay until I started a shallow descent, whereupon I experienced a large rotor overspeed and yaw to the left. By the time I got the nose under control and hit the switch back to Normal, the main rotor had been overstressed for maybe 5 seconds or more. "Now I'm a little intimidated about this realm of flight. Maybe you could shed some light on the ins and outs of the Idle Up modes in one of your future columns. "Many thanks for your fine efforts! (Shuttle ZX, RD6000 radio, O.S. .32 SX-H, JR 120BB gyro. TT muffler. NMP 550 Razors)" I like this letter because it gives me a lot of information about equipment and pilot skills and experience. It's much more useful than the E-mails that arrive with something like, "Why can't I get my Raptor to climb inverted?" It seems as though the transition from nonaerobatic flying and hovering to the more advanced aerobatics and 3-D flying is a major sticking point for many pilots. At my shop we get calls every day from pilots who are lost at this stage of the game. So I'm going to rehash prior comments here in hopes that I can take some of the difficulty out of this challenging phase of helicopter flight. When I first started using "idle-up" modes, I too was uncomfortable with the fact that in "normal" mode I hovered at midstick (the old "tradition") and in my idle-up modes I hovered at three-quarters stick. Among other things, it meant that switching into idle up from the normal mode while in hover was never smooth and precise. I either watched the helicopter drop as the pitch changed from hover pitch to zero pitch or I overcorrected and the helicopter shot up as I advanced the stick to three-quarters when I activated the idle up. So I changed my setup to allow more consistency in hovering between the various flight modes—and between upright and inverted hovering. The typical V-shaped 3-D throttle curve was inarguably the only way to go for the idle-up night mode, so I changed my setup in 24—L> normal mode to have zero pitch at •.;;;•'!••• midstick and hover pitch at three-quarters stick. I also changed my throttle-hold pitch curve to have zero pitch at midstick, leaving the top and bottom points alone. No matter what flight mode is active, I know that midstick is zero pitch in the main blades and that hover will be at approximately three-quarters stick. Whether I'm hovering or in forward flight, I can change flight modes transparently without the helicopter dropping or jumping. (For those uninterested in aerobatics, there is no advantage to this style of setup. In fact, it compresses the throttle/collective response to stick travel from hover to full stick, which makes the throttle/collective h; more sensitive in that region. So if you are mainly interested in precision hovering, it's probably best to stay with the traditional "hover at midstick" setup.) You will need to adjust the throttle curves to match your new pitch curve. If you are used to hovering at midstick and you change to zero pitch at midstick, obviously the throttle setting at midstick will need to be lowered. That brings up another advantage of the setup I describe: since all modes are zero pitch at midstick, the correct throttle setting for all flight modes is the same for midstick through full stick unless you want to run different head speeds between the different modes. In setting the throttle curves, remember this: you can measure the pitch, and you cannot measure the power. So you should set the pitch curves first, using a pitch gauge to ensure that you have the settings you want for hover and zero-pitch positions. Then leave those pitch positions alone. Since you can't measure power output with a ruler or a gauge, you have to reach the proper throttle-curve settings through flight testing. The full-stick position is simple: you want the throttle barrel at the wide-open position. Idle is almost as easy; you want the carburetor open just far enough to run steadily at low stick (normal mode) and still have enough servo travel to kill the engine with your throttle trim or kill switch. For hover throttle position, you can start at approximately 50% throttle and tune from there, which means that if your model's head speed is too high, you reduce the throttle opening at hover: if head speed is low. you increase throttle. The same adjustment is made for any other point(s) between the extreme stick positions: if the head speed is wrong, you fix it with throttle-curve adjustments. When you are at full stick, the rules change—because you are at maximum throttle, and that's where you want to be. So at full stick you adjust the pitch setting to be compatible with the maximum power output of your engine. If the head speed slows at full stick, decrease the pitch until the head speed stays consistent: if the rotor speeds up at full pitch, you increase pitch. While I'm discussing throttle setup, there are two other points of concern to address from the start. First, you want to have the throttle arm positioned so that at midthrottle it is parallel to your throttle servo's output ami. This will help keep your throttle response more linear, and it's a good practice no matter what type of flying you plan to do. Second, you will probably need to make sure that the throttle channel endpoints (ATV) arc set at maximums and that full stick is at 100% on your throttle curves. The reason for this is that you will want to use cyclic to throttle mixes for aerobatics, to mix in the power needed to perform these maneuvers. You can't manually add throttle during, for instance, a flip or a stationary roll because you would be changing the pitch setting too. With most radios, this cyclic to throttle mix can overdrive the throttle servo if you have not already maxed out the travel adjustment on the top end. (The JR 10X. Futaba 9ZH. and Airtronics Stylus with helicopter card arc the few I'm aware of that don't have this issue.) Finally, you may have to address the revo-mix function on your radio. If you (like most people these days) are flying in heading-hold mode, all you need to do is make sure that revo-mix is off or zeroed out completely in all flight modes. If you are flying a non-heading-hold gyro, you do need a revo-mix. In your 3-D flight mode, the mix output will be the same at full stick as at full low stick if 'your radio allows you to set midstick as the zero point for the mix. Venture Mania? We have several of the new JR Venture GPs flying, and they are proving to be popular helicopters. Of course, some people can't be happy with any helicopter unless they can squeeze in more horsepower. There are many ways to do this, but the simplest is the way my flying buddy and co-worker Kurt Kreiger did it: he used the engine mount for the Ergo 46 and drilled the stock Venture fan to fit the shaft (using a drill press). As with the Ergo conversions, he did have to cut a bit of the crankshaft off his O.S. .50. Then he installed the long boom and belt from the Ergo 46, and viola! Now he has a rather overpowered, smooth and agile Venture CP 50. With Mavrikk 600mm carbon blades, the Venture is still smooth and agile, and it climbs and autorotates like a 60 machine. Kurt did add a few other items, including a DBC header tank. Mavrikk dual boom supports (to allow access to the plug), and some carbon fins. He's also using the new Venom Racing Temperature Monitor, which is working very nicely, and the Mavrikk 50 muffler. Any decent helicopter shop can get you the parts to make this conversion if you are interested. We're still looking for a larger tank that will fit this frame set. Again, I've overused my space allotment. Until next time, fly safely and happy rotoring!
Edition: Model Aviation - 2002/10
Page Numbers: 112, 113
Edition: Model Aviation - 2002/10
Page Numbers: 112, 113
IT'S ANOTHER GREAT month to be enjoying the sport of Radio Control (RC) helicopters! Almost everywhere in the country this is peak flying season. I hope you are all enjoying all the time you get to spend with this great sport and hobby. I've been getting many letters and E-mails lately. Thank you. My requests for input about what topics to cover got exactly the response I expected, and they were roughly evenly divided among "more flying stuff." "more setup stuff," and "more product stuff." I've been writing long enough to know that you can't please everyone with every column, so I'll keep trying to give some coverage to all three of those areas and a few other things as best I can. From all those I received, the following is an "average" letter from Dave Stafford. "I'm an avid reader of your column in MA and I noticed your request for input in the latest issue. Having started fixed wing RC back in 1970, I guess I could be classified as an old-timer, but my experience with RC helicopters only goes back five or six years. In that time, I've learned how to fly my entry-level Shuttle ZX in FF, nose-in hover, out-front 360s as well as stall turns (only about 60 degrees nose up, however), horizontal 8s, constant-rate descents to landing, etc. "Not all that long ago I would've been happy with those skills, but now I'm getting bored. I would like to improve my flying skills, but realize that I must master the proper setup of the so-called Idle Up modes before going much further. "I'm having a difficult time getting my radio programmed for Idle Up flying. I would prefer that there be no noticeable change when hitting the switch while in a hover. I've accomplished that part of the setup, but run into trouble in the realm of 0 degrees pitch and below. "The first time I used Idle Up I, the helicopter flew okay until I started a shallow descent, whereupon I experienced a large rotor overspeed and yaw to the left. By the time I got the nose under control and hit the switch back to Normal, the main rotor had been overstressed for maybe 5 seconds or more. "Now I'm a little intimidated about this realm of flight. Maybe you could shed some light on the ins and outs of the Idle Up modes in one of your future columns. "Many thanks for your fine efforts! (Shuttle ZX, RD6000 radio, O.S. .32 SX-H, JR 120BB gyro. TT muffler. NMP 550 Razors)" I like this letter because it gives me a lot of information about equipment and pilot skills and experience. It's much more useful than the E-mails that arrive with something like, "Why can't I get my Raptor to climb inverted?" It seems as though the transition from nonaerobatic flying and hovering to the more advanced aerobatics and 3-D flying is a major sticking point for many pilots. At my shop we get calls every day from pilots who are lost at this stage of the game. So I'm going to rehash prior comments here in hopes that I can take some of the difficulty out of this challenging phase of helicopter flight. When I first started using "idle-up" modes, I too was uncomfortable with the fact that in "normal" mode I hovered at midstick (the old "tradition") and in my idle-up modes I hovered at three-quarters stick. Among other things, it meant that switching into idle up from the normal mode while in hover was never smooth and precise. I either watched the helicopter drop as the pitch changed from hover pitch to zero pitch or I overcorrected and the helicopter shot up as I advanced the stick to three-quarters when I activated the idle up. So I changed my setup to allow more consistency in hovering between the various flight modes—and between upright and inverted hovering. The typical V-shaped 3-D throttle curve was inarguably the only way to go for the idle-up night mode, so I changed my setup in 24—L> normal mode to have zero pitch at •.;;;•'!••• midstick and hover pitch at three-quarters stick. I also changed my throttle-hold pitch curve to have zero pitch at midstick, leaving the top and bottom points alone. No matter what flight mode is active, I know that midstick is zero pitch in the main blades and that hover will be at approximately three-quarters stick. Whether I'm hovering or in forward flight, I can change flight modes transparently without the helicopter dropping or jumping. (For those uninterested in aerobatics, there is no advantage to this style of setup. In fact, it compresses the throttle/collective response to stick travel from hover to full stick, which makes the throttle/collective h; more sensitive in that region. So if you are mainly interested in precision hovering, it's probably best to stay with the traditional "hover at midstick" setup.) You will need to adjust the throttle curves to match your new pitch curve. If you are used to hovering at midstick and you change to zero pitch at midstick, obviously the throttle setting at midstick will need to be lowered. That brings up another advantage of the setup I describe: since all modes are zero pitch at midstick, the correct throttle setting for all flight modes is the same for midstick through full stick unless you want to run different head speeds between the different modes. In setting the throttle curves, remember this: you can measure the pitch, and you cannot measure the power. So you should set the pitch curves first, using a pitch gauge to ensure that you have the settings you want for hover and zero-pitch positions. Then leave those pitch positions alone. Since you can't measure power output with a ruler or a gauge, you have to reach the proper throttle-curve settings through flight testing. The full-stick position is simple: you want the throttle barrel at the wide-open position. Idle is almost as easy; you want the carburetor open just far enough to run steadily at low stick (normal mode) and still have enough servo travel to kill the engine with your throttle trim or kill switch. For hover throttle position, you can start at approximately 50% throttle and tune from there, which means that if your model's head speed is too high, you reduce the throttle opening at hover: if head speed is low. you increase throttle. The same adjustment is made for any other point(s) between the extreme stick positions: if the head speed is wrong, you fix it with throttle-curve adjustments. When you are at full stick, the rules change—because you are at maximum throttle, and that's where you want to be. So at full stick you adjust the pitch setting to be compatible with the maximum power output of your engine. If the head speed slows at full stick, decrease the pitch until the head speed stays consistent: if the rotor speeds up at full pitch, you increase pitch. While I'm discussing throttle setup, there are two other points of concern to address from the start. First, you want to have the throttle arm positioned so that at midthrottle it is parallel to your throttle servo's output ami. This will help keep your throttle response more linear, and it's a good practice no matter what type of flying you plan to do. Second, you will probably need to make sure that the throttle channel endpoints (ATV) arc set at maximums and that full stick is at 100% on your throttle curves. The reason for this is that you will want to use cyclic to throttle mixes for aerobatics, to mix in the power needed to perform these maneuvers. You can't manually add throttle during, for instance, a flip or a stationary roll because you would be changing the pitch setting too. With most radios, this cyclic to throttle mix can overdrive the throttle servo if you have not already maxed out the travel adjustment on the top end. (The JR 10X. Futaba 9ZH. and Airtronics Stylus with helicopter card arc the few I'm aware of that don't have this issue.) Finally, you may have to address the revo-mix function on your radio. If you (like most people these days) are flying in heading-hold mode, all you need to do is make sure that revo-mix is off or zeroed out completely in all flight modes. If you are flying a non-heading-hold gyro, you do need a revo-mix. In your 3-D flight mode, the mix output will be the same at full stick as at full low stick if 'your radio allows you to set midstick as the zero point for the mix. Venture Mania? We have several of the new JR Venture GPs flying, and they are proving to be popular helicopters. Of course, some people can't be happy with any helicopter unless they can squeeze in more horsepower. There are many ways to do this, but the simplest is the way my flying buddy and co-worker Kurt Kreiger did it: he used the engine mount for the Ergo 46 and drilled the stock Venture fan to fit the shaft (using a drill press). As with the Ergo conversions, he did have to cut a bit of the crankshaft off his O.S. .50. Then he installed the long boom and belt from the Ergo 46, and viola! Now he has a rather overpowered, smooth and agile Venture CP 50. With Mavrikk 600mm carbon blades, the Venture is still smooth and agile, and it climbs and autorotates like a 60 machine. Kurt did add a few other items, including a DBC header tank. Mavrikk dual boom supports (to allow access to the plug), and some carbon fins. He's also using the new Venom Racing Temperature Monitor, which is working very nicely, and the Mavrikk 50 muffler. Any decent helicopter shop can get you the parts to make this conversion if you are interested. We're still looking for a larger tank that will fit this frame set. Again, I've overused my space allotment. Until next time, fly safely and happy rotoring!
