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Originally Posted by shockwaveriderz
Thanks George....
what do you think about the Gasparin Penta? Any experiences or knowledge about them?
Which Spektrum Model are you using? I was aware of them but I didn't know which was which..?
something along these lines:
Spektrum AS6410L DSMX 6-Channel Ultra Micro AS3X Receiver
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Those Gasparin receivers are 35 mHz, I think, though he does seem to offer 72 mHz. I have no experience with them and would go with what is compatible with my Spektrum Tx, if the range seemed reliable. I found a great way to range test receivers using electric planes. Use two transmitters and two receivers. The "test" receiver on throttle only, and fly upwind until the throttle went dead. Glide back into range and get throttle control back. I had the luxury of a borrowed transmitter to fly the plane with, for the non-throttle controls.
Oh, WATCH OUT for "AS3X" receivers! They have auto-stabilization features which are GREAT for beginners when it comes to a plane flying horizontally (will self-level the wings and fuselage). An accident waiting to happen for an R/C RBG boosting vertical. Because the receiver would try to "stabilize" it to boost horizontally. You CAN disable that feature, but have to be totally aware of that and check the manual to do it (I've never used one for rocket power, and the electric planes that DO have that feature, I have left it on). Also, if you fiddle with settings and have a suitable transmitter, that feature can be turned on and off during flight (like off for boost and on for glide)
Actually, I have to admit I've not done a ground test to see what would happen if the "plane" with AS3X was pointed vertical at power-up, when it takes its calibration readings, if it could be tricked into wanting to make the model fly vertically. But then it would be totally unflyable horizontally, it would want to keep tryin ot pitch up, so it would need to be turned off after boost. My guess is it's "hard coded" not to accept calibration in that manner, it would require being hooked up to a computer with special software if possible at all with AS3X (Or mount an As3X receiver at 90 degrees to keep the receiver horizontal while the rocket was vertical, as Alyssa Stenberg did with her Eagle Tree Guardian rocket guidance project). I did experiment a few years ago with a 5 gram "Drone" type of flight controller, that also could auto-level planes, to see if it could be turned on and off to make a modle plan try to climb vertical. It worked. Every time I turned it on, the plane quickly nosed up and tried to climb vertical, but it didn't have enough thrust to maintain. Although there was an issue with another component I needed at the time that a later controller would get rid of. I never got around to trying it in a R/C RG. But to set that up required using a special computer application to adjust all the parameters, including to tell it where "UP was regardless of which way the board pointed.
Anyway, not quite intending to jump this thread off into "what can be done with AS3X technology for boost" branch, just WARNING that if you did not know the above it could be nightmare if not disabled. Also, while useful for total newbies to learn to fly, the AS3X should be turned off after learning to fly well enough, to then learn how to fly a model without any stabilization assist. IOW - REMOVE the Training Wheels.
As for my Spektrum transmitter, I am using a DX-18. Which is a bit overkill, but it has a lot of great features. I'm able to program it so that a single toggle switch does everything I want to go from boost mode to glide mode. I've had that kind of Boost/Glide switch since 1986, but back then I had to rewire and modify the transmitter (Futaba 7FG/K) just to change the elevator trim and change dual rates (I rewired the channel 7 lever to become the boost trim lever and toggled from that to the normal elevator trim lever). Improved those over time with other transmitters. But the DX-18 allowed me to also be able to adjust rudder trim changes between boost and glide as well as elevator and dual rates and everything else (like automatically separate shuttle orbiter from ET, and make shuttle orbiter rudder move opposite for boost because left rudder would cause right roll on boost so left rudder stick caused right rudder motion to cause left roll of shuttle on boost. Actually I had those features on a previous computer transmitter, I list those as examples of very important things that can be done all at once wit the flip of one switch).
On my old Futaba-G transmitter that I rewired for the channel 7 lever to be boost trim, and adding a toggle switch to go from boost elevator trim to glide elevator trim, I had to pre-set other swtiches before boost. Like Dual Rate elevator and dual rate rudder. And inside the back panel of the transmitter, to change reverse switvhes to their proper setting for a given model, as well as adjust trimpots for the throw settings. PER MODEL. For a flight I'd set all the toggle switches, usually three, for boost. Then for glide, flip all of those switches for glide. Once, when changing to a different model, I forgot to change a back panel servo reverse switch for the rudder. The model boosted fine. For glide, it started to turn left. I gave right. It turned more left. I gave more right. It spiraled into the ground before I realized the rudder was reversed and my "right" rudder input was turning it more left. I had too many R/C RBG's to risk letting that happen again. So in 2 months I got a computer transmitter (Ace Micropro) that had model memories so that problme would not happen again. But I still needed to do some wiring mods to do the boost/Glide trim for elevator and sacrifice the channel 7 lever for boost trim.
I keep mentioinng the boost trim for a reason. Gliders with a good glide trim will pitch nose-up if you make them go too fast. So on rocket boost they will nose-up a lot (unless an old-school long-pop-pod type glider). So the elevator needs to be flatter for boost, approximately zero pitch trim. So thids is why two separate trims are very useful. And you don't just "eyeball it". Well, you take a shot on the first boost, using a shorter burn motor. See how it goes. Adjust boost trim and try again. And again, going to a longer burn motor when the trim is in the ballpark. Until you get it dialed in. Still that trim would "go away" when swapping models, using the old style analog trims.
With modern computer radios, with ELECTRONIC TRIM, the trim setting are in the model memory, which is a fantastic improvement. In 2008, I was in a flyoff at the WSMC in the S8E/P event, but my best model that I'd trimmed and adjusted for days had drifted off a mile or more in massive winds in the 3rd round, flying away due to a strategic choice to maximize duration and sacrifice landing points (which is what got me into the flyoffs). Anyway, I had to go to a back up model I had not rocket boosted in 2 years. So I had to trust that the trims were still right (and hope it had not warped in storage). It boosted just fine, in 20 mph wind, the boost trim just like I had flown it last, and the glide trim was good too (earned a silver medal more by strategy than by piloting skill, and having solidly reliable models that were trimmed so I didn't have to fight them on boost).