Gordon Bushell Posted September 30, 2012 Share Posted September 30, 2012 Last weekend I was left with only my Apprentice trainer airworthy, so took it out for the afternoon. I turned on the tx, and then powered up the plane, foolishly leaving the throttle open. The ESC went into progamming mode, so I closed the throttle, the ESC made it's usual arming tone, and assumed all was normal. I carried out a control surface check, which was normal, carried the plane out onto the patch, and attempted take-off. Whilst the control surfaces answered, the throttle was in-operative. So, I went out, and retrieved the plane, and went through a power off -power on cycle (tx and plane). After this, the controls all worked, and the throttle answered. I took off and did a few circuits, and some gentle trainer style loops and rools, out to some distance away. I had just crossed the field boundary, straight and level at around 50-60', when I heard the motor spool down. I thought "that's strange", and tried to open the throttle, and then gradually the nose dropped and she just dropped onto the field, probably at no more than 20 or 25 degrees. There was no sign of any answer to up elevator, and she stayed absolutely level in roll. She was definitely travelling faster than I would normally land, and more nose down. If I slow too much on landing she normally drops her port wing gently, and she showed no sign of that. The prop is bent but not broken, and the nosewheel/bulkhead appear fine, so she didn't land terribly hard. There are a couple of cracks in the plastic motor case, which I expected, and will need to replace the motor, prop and have a good look. Before I disconnected the battery I checked the reciever, which showed a solid orange light, so presumably no power interuption on the plane/rx. The controls were working and the throttle answered. Where would you look? It strikes me that the failsafe had cut in (throttle cut and no control throw). The tx is an old DX5e (battery indicator LEDs middle of range), the rx an AR500, and the ESC with bec is the standard fit for the plane. I only put 330mAh back into the 3200mAh battery on the plane. Everything has worked well since I stopped using a DSMX tx with the plane after it's second flight, and we've had 35 uneventful flights since then. I guess (apart from the mechanical stuff) it's a case of checking all the radio connections, waggling all the wires, range check, and then suck it and see... Cheers, Gordon (who is regretting any comment on the "how good are you" thread...) Quote Link to comment Share on other sites More sharing options...
malcolm woodcock 1 Posted October 1, 2012 Share Posted October 1, 2012 What kind of Rx were you using, was it a Parkflyer or the full range. Were the aerials arranged at right angles to each other. It seems that you might have had a 'brown out' long enough for the failsafe to kick in. Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 1, 2012 Share Posted October 1, 2012 Could be a leccy problem rather than radio. It is possible that you inadvertently re-programmed the ESC when you shut down the throttle during the programming procedure, possibly the cell count or adjusting the cut-off value to high which can be varied on some ESC's from 2.7-3.1V/cell. The symptoms sound just as likely to be LVC as the failsafe cutting in. If you only used 330mA from the pack, that would tie up with the LVC cutting in at a 4S setting, ie 12V.... Pete Edited By Pete B on 01/10/2012 09:57:39 Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 1, 2012 Share Posted October 1, 2012 The orange receivers are only really classed as park fly, but I have found them to be excellent on range, and use several in some 60" slopers with no problems. It cant have been a brown out as the OP confirms the LED was solid, and besides, failsafe will only operate on loss of signal, not a brown out which is PURELY power supply related. Edit: Pete B's explanantion is very plausible - well done Pete. Edited By Tim Mackey on 01/10/2012 10:00:58 Quote Link to comment Share on other sites More sharing options...
Robin Kearney Posted October 1, 2012 Share Posted October 1, 2012 Tim, I believe the AR500 is a real Spektrum full range RX, replaced by the AR600 but much the same iirc. As for the explanation, I like Pete B's idea too! Maybe that throttle high alarm on my TX isn't just there to annoy me! r. Quote Link to comment Share on other sites More sharing options...
Alan B Posted October 1, 2012 Share Posted October 1, 2012 Hi Gordon Just as a matter of interest. I have flown loads of times using Specktrum AR500 rx on DSM2 and never had any problems whats so ever. The only time i have any problems with the AR500 rx is when the TX is on DSMX. AL Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 1, 2012 Share Posted October 1, 2012 Posted by Alan B on 01/10/2012 12:15:22: Just as a matter of interest. I have flown loads of times using Specktrum AR500 rx on DSM2 and never had any problems whats so ever. The only time i have any problems with the AR500 rx is when the TX is on DSMX. IIRC, that was an issue which was corrected some time ago when many earlier DX8's had to be returned to Horizon for a firmware update - it won't be problem with more recent Tx's or if the update has been done. I don't know if the Tx recognises an AR500 Rx and binds in DSM2, rather than DSMX, given the choice. I can't use DSMX anyway - the French setting only uses DSM2. Pete Quote Link to comment Share on other sites More sharing options...
Gordon Bushell Posted October 1, 2012 Author Share Posted October 1, 2012 My DX6i is one of those that requires the firmware update, the apprentice is the only plane I have with a DSM2 rx, so I use the DX5e that came with it to fly it. One of these days I'll decide I don't need the DX6i for a week or two, and get it sorted out. When using the DX6i with the DSM2 AR500 I had some strange and unwanted behaviour, which the update should sort out. It is not related to this problem. Or should not be, at least. It will be worth going over the ESC settings, and I'll check the LVC. I'd have thought that I'd still have had some response to the controls with LVC in, though I've never hit LVC before to see what happens. I'd have said that I'd have been in with a good shout of gliding down from where the motor cut, unless I did something particularly stupid while thinking about the motor having stopped. I don't think that fits with a gentle nose drop with level wings though, then straight to ground. My fellow fliers thought it was just a rough landing! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 2, 2012 Share Posted October 2, 2012 Dunno why I thought it was an orange rx - senior moment Quote Link to comment Share on other sites More sharing options...
Gordon Bushell Posted October 15, 2012 Author Share Posted October 15, 2012 Today I had a go at fixing up the apprentice - new prop and different motor, straightened up the front u/c leg, and checked things over. The CG looks about right, the current draw is about right, so I think we're good to have a trial. I haven't found any fault on the plane's electrical system. I _think_ I may have had duff batteries in the transmitter - the indicator LEDs showed a good battery that dropped rapidly to the lowest green LED. I couldn't get any response from the rx until I changed the Tx batteries, and the esc didn't arm (presumably no throttle signal?). Slightly embarrassing that... Unless of course there is some intermittent fault I'm unaware of. Quote Link to comment Share on other sites More sharing options...
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