Allan Bennett

A cardboard box of Big Macs doesn't sound like a very secure load, especially when it gets soggy in wet weather.

Getting the right pitch and diameter for an electric model is quite an art -- or more likely, trial and error. With one of my models I achieved the motor's rated amps using an 11 x 7 prop, but take-off was a bit leisurely. Changing to 12 x 6 achieved roughly the same amps but a much more rapid take-off, and lower theoretical top speed was not an issue.

Can the motor shaft be moved so that it protrudes at the other end? This can be done with some similar outrunners, allowing you to then mount it behind the front wall of the engine bay.

Packs charged in parallel need to be the same cell-count and approximately the same state of charge (i.e. same voltage) when connected to the charger. They don't have to be the same capacity though, for the charger will keep them at the same voltage as each other by not pushing as many amps through the smaller pack. If you already fly models using 3S and 4S packs, why not hook them up in series when your model needs 7S or 8S. In that scenario they don't need to be the same cell-count but they do need to be roughly the same mAh capacity. Your flight duration should be determined by the finishing voltage of the smallest pack. I'm afraid I'm not up to date with current chargers so, with the demise of the PowerLab 8, I can't help you on that aspect.

I passed this on to another club member who's had more Betaflight and Spektrum experience than I have, and he's come to the conclusion that the Eachine's FC is defective. The club member who owns it got if from Bangood, so we're not hopeful of a positive response from them, but will ask for a warranty replacement.

When I was about your age (😁) I was the very sasified owner of a high-end Futaba transmitter, with the 'if it ain't broke, don't fix it' attitude to things electrical. But then I set up motor diffential on my Multiplex Twinstar to aid ground handling, but couldn't figure out a way to program the Futaba's throttle-cut switch to act on both throttle channels. Someone on this forum suggested that FrSky Taranis with OpenTX could do it, and they were right! I quickly converted all my models to FrSky and sold all my Futaba FASST receivers for more than the cost of the replacement FrSky ones. For me the beauty of OpenTX is its flexibility; I can program any stick or switch to do anything, and I can also program them to tell me what they're doing. I don't even try to do any programming in the field, rather doing it via the computer interface at home.

I've tried selecting each of the UARTs in the Ports screen in turn, but still no joy. I've also watched a YouTube video by Horizon Hobby, which shows some CLi commands required, but I've tried those (some are invalid) and still no change. Seems like Betaflight has moved on since that video was made, for SPEKTRUM SRLX2 is now a drop-down option in the Receiver screen, which it doesn't seem to have been the case when the video was made.

I'm in the process of setting up a clubmate's Eachine X220v3 quadcopter with a Spektrum SRXL2 receiver, using Betaflight. Thus far I've soldered the connector to the SRXL2 and spliced the supplied 4-wire cable to the 3-wire one from the Eachine, dispensing with the SRXL2 unused wire. The SRXL2 is successfully bound to a DX6 transmitter and has a solid orange LED when I connect it to the Eachine board and power up the board. My problem is that when I connect to Betaflight, with the Eachine powered, I can't get any response from any of the channels, though the quad picture on the home screen moves correctly in response to movement of the Eachine. Here are screenshots of my Rx connection to the Eachine, and of the Ports and Receiver screens in Betaflight: I'm sure I must be missing something in the basic setup, so any hints would be welcome.

AndrewL, are you experienced at flying RC model aircraft? If not, apart from all the good advice above, I would suggest that you need to be able to fly an RC aircraft manually before you start making it 'autonomous'.

I'm really pleased with the Benedini sound system I have in my Magnatilla. It also has a machine gun sound which is coordinated with a flashing bright LED in the muzzle of the gun. Brings a smile to the faces of many of our club members when it's flying, and can be heard when in the sky, sometimes even when there's a glow model flying too!

Maybe we're getting too paranoid. Or maybe they do phone home via all that Huwai (spelling?) mobile phone equipment. It's also been suggested that when one has a flyaway it's because they've gone home to report 😄

A switch is a potential failure point, so better in my view to plug in the old NiMh pack if testing without the motor is required. Or simply remove the prop.

Ever since I switched to 2.4GHz I've been using stand-alone BECs in place of the Rx batteries that I used with my opto ESCs. They're all connected directly to the ESC's battery plug. Never a problem in 20 years or so.

Yes, if they're switching BECs (common these days), it can hurt one or both of the BECs because of voltage and/or frequency mis-match. If they're linear BECs (usually a lower amps capability) and the same spec you can usually connect them together to increase the available amps.

I actually use a Shottky diode device which isolates the two BECs from each other and lets one continue to supply power to the Rx if the other fails for some reason. Without the isolator I would definitely pull one red wire out of its connector.

Yes, so each throttle is on a separate channel. The first one is on my regular throttle channel (3) and the other one is on 6, linked to 3. Then one channel is given a + rudder mix and the other is given a - rudder mix. I use that on my Multiplex Twinstar too, though with greater rudder input, to assist with ground handling.

Just remembered, instead of working rudders I've programmed a slight rudder -> throttle mix into mine. My ESCs are in the fuselage to minimise battery wire length, and I've had no problem with c of g.

Oh dear, I've just weighed mine and it's 1258g without battery. Glassed with 25g cloth, and painted.

Thanks David. I'll try and keep it closer next time, as well as possibly taming the throws. But I need nice weather to be motivated.

Yes, my maiden ended up badly! Take-off and climb out were okay, but when I started a left turn into the circuit I got disoriented and the end result was it went into the ground. Luckily a soft cultivated field, so damage wasn't bad, and it's ready to go again. Just waiting for better weather now, and will review control surface throws, for it was much too lively for my liking.

Being new to 3D printers it took a prompt like yours about temperature too high to start me heading in the right direction. While sorting this issue I've learned a lot about how the machine works. All thanks to this great forum and its contributors.

Problem solved Looking more closely at the print head I realised that the fan with the black/yellow wires is the one at the right, which directs air onto the print. The black/red wires from the front fan go to the two screw terminals at the back of the board marked 'H' on the plan posted by RottenRow. Having realised that I then checked with my voltmeter to verify that there was 24v at those terminals (there was) and I noticed that the black wire was in the socket with the screw tightened down, but was loose. It was below the clamping plate, so wasn't being clamped when the screw was tightened. Replacing it correctly has the fan working again. Thanks to everyone for their advice and patience!

Thanks for confirming my fan cable connection RottenRow. When I Googled for such a diagram I didn't get that one, and the ones I did get were usually a slightly different board with only a single socket where there's a pair of sockets on mine. Anyway, that rules out one thing. Next thing I've got to check into is several references to two fans at the print head -- one to keep the filament feed cool, the other to cool the print. In my case the fan that's mounted on the front of the print head which I assume is the 'hot end fan' because if's facing the metal feed tube and is described as such in how-to videos, has black/yellow wires so is preumably the one that's plugged into the board as shown in RottenRow's diagram but is described there as the 'part cooling fan'. I need to double-check those wire colours, for in videos I've seen about replacing that fan, it has black/red wires. I haven't yet taken off the other device on the right side of the print head. It looks like it should be a fan, though it's visually bery different from the front one, and has black/red wires, which would seem to match those shown in the diagram as 'H Red/black hot end fan'.

I think you've hit the nail on the head! The hot end fan isn't running at all. I don't know when it stopped, but I'm wondering if it's only the low temperature of my unheated workshop (aka garage) keeping the heat block cool that allowed me to print earlier in the week. Mid this afternoon, after a couple of failed attempts to print, the ambient temperature dropped and I was able to complete a 90-minute print with only a few judders of the feeder. I've checked the fan connection to the motherboard, and it appears to be good. The motherboard fan came on after a while, so at least there's a 24v supply there, so tomorrow I'll check the voltage where it goes into the fan, to make sure it's not disconnected somewhere along the way. I saw in another forum that the fan can be disable by the splicer, but I've checked and the setting on mine (Creality Slicer 4.8) is for fan to be on after the 4th layer. Hmmm, I wonder if the connectors to the motherboard are wrong way round, and the motherboard fan came on after 0.8mm or the 4th layer. The two fans are connected the way they were when I received the Ender, so that's another thing to check tomorrow. The 2-pin black/yellow plug at the left is the hotend fan; the 2-pin black/red one is the motherboard fan. Can anyone check if their connections are the same on their Ender 3 board?

Thanks PeterF, I didn't dismantle mine enough to see all that. Makes sense. I'll check the action of my fan -- it certainly was working a couple of days ago.