Mark Stevens 1 Posted March 4, 2018 Share Posted March 4, 2018 Now all you have to do is get your hands on a Vintage Helicopter and compare it to the one you've just built. The Vintage one will come out tops in terms of simplicity and they actually fly very well considering we did not have Gyros or extra onboard stabilisation back in the early days. The hard work was already done. The newer machines today are way too over engineered. As you can probably guess I'm a fan of Vintage RC Helicopters and have quite a few of them. Mark Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted March 4, 2018 Share Posted March 4, 2018 Here's what might become my favourite servo centre-ing setup. I've not compared its centre point to that of my FrSky receivers yet but being digital it has every chance of being very close or spot on. Quote Link to comment Share on other sites More sharing options...
Josip Vrandecic -Mes Posted March 4, 2018 Share Posted March 4, 2018 Dear BEB , How much do I know about your technical knowledge and of course the wisdom of the "silver hair" I know and believe that everything will go and be alright .... and perhaps a new sentimental connection might be achieved towards the helicopters ...who knows ?! Note: Greeting from me and my flu...(it feels like I'm talking and writing stupidity by body temperature) Edited By Josip Vrandecic -Mes on 04/03/2018 21:05:25 Quote Link to comment Share on other sites More sharing options...
Barryorbik Posted March 4, 2018 Share Posted March 4, 2018 Hi BEB, Not sure what it suggests in you transmitter manual but its a really good idea to make sure you set up a motor throttle cut to zero and I would suggest you move the motor out of mesh with the main gear whilst setting up the G Pro, as having the main blades unexpectedly spin up to 3,000 rpm and the tail rotors at four times that can cause serious injuries. Hardest thing with helicopters is getting the tail to feel right and most of the experienced helicopter fliers at our club with Trex 470's have ditched the G Pro for Vortex or Beast X FBL's, as they failed to get the tail right with the G Pros. Enjoy the challenge. Barry Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted March 4, 2018 Share Posted March 4, 2018 BEB: I don't know if you saw the link I posted in the other thread about using OpenTx on helicopters, but there is one "Gotcha" to watch out for: **LINK** It is mainly concerned with IC engines and the dangers of "hot starts" - an ESC should simply refuse to arm in similar circumstances, but might make you wonder why nothing is happening! The problem is that applying a throttle curve in the wrong place can have unexpected results if you adjust the hovering throttle settings. Even though the throttle trim is set to "Idle-only", it doesn't actually mean that and can result in a "hot start" - as I found out! Have a read of the thread, and have a look at my sample set-up in the last post. Also note that there is an inconsistency in where any over-riding throttle setting should be placed (throttle-cut) depending on whether you apply it at the input stage or the mixer stage. I'm still using 2.1.9 - the issue may have been addressed in 2.2.X, but don't count on it! The only reason I'm still on 2.1.9 is that the helicopter setup in particular is quite complex on a vintage IC collective pitch model, and I need time to thoroughly check that everything is working as expected. It is now, but I did have a fright initially, and I don't want another anytime soon! As I say, an electric set-up should be safer, but if you don't apply the curves in the right place, you will get some unexpected side effects! Best of luck! -- Pete Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 5, 2018 Author Share Posted March 5, 2018 Hi, thanks for the comments and advice chaps - all very welcome! @Chris - yes I have that facility on my Watt meter which has a servo test function. The advantage of course is if you want to get the servo exactly in the middle, then set to 1500 (assuming of course that the meter is accurat!). Butin my case its quite a bulky box the Watt meter so I tend to trust to the Mk1 eyeball to say that the servo is centred - and for 99% of cases I can probably get away with that! Handy facility in a tester though it has to be said. @Jo - Thank you for your good wishes. I'm really sorry to hear that you have flu! And sadly I find our women aren't always as sympathetic with us as they could be - claiming we are exagerating which of course is grossely unfair! I hope you feel much better very soon! @Barry - thanks for those comments Barry. Don't worry I always implement "belt and braces" where throttle cuts are concerned. Good advice re taking the motor pinion out of mesh, I'll certainly remember that, thanks. @Peter - a very interesting link that, and sonmething to keep in mind. I do tend to make extensive use of the Tx simulator in Companion, through this I can devise a thorough test sequence and check that the channel outputs are doing exactly what I intend them to do in every case. I shall certianly add that case to the list of test scenarios for my programming. As you say I am unlikely to see the issue "in the flesh" as any good ESC wouldn't arm under such conditions. But it still should be checked and eliminated in the programming if possible, the ESC's interlocks should be the "last line defence", not the default safety measure in my view! As an aside: I think the Tx simulator is a sadly underused facility in OpenTx - it provides a safe "play ground" for loads of complex ideas and space in which you can check that in doing "A" you haven't inadvertantly altered "B"! I have suceessfully trapped a number of bugs in my Tx programming at the simulator stage which (at the least) saves annoyance and embarassment and (at the most) could save your life! I have been using OpenTx for over two years now and I find that it is a feature of it that, while it gives you great power and flexibility, it does so at the potential cost of giving you less automatic protection. Don't get me wrong, I don't believe OpenTx is in any way "unsafe" - but it does put the onus on us, as users, to implement our own protection and failsafe systems. While a purely menu-driven programing system often simply will not give the options to do something potentially dangerous - OpenTx will allow you to do anything! So I think that means it really comes back to being up to us, we have to take care of this issue, no "nanny" to look after us! So we have to implement overall cut-outs, software interlocks, switch checks, extra safety logic to stop us doing the wrong thing! And as I say I find the simulator an enormous help in doing that. It enables me to connect the model together for the first time having already gone through all of the operational proceedures I will use in practice. I can then do them again, this time "for real", and double check that there are no surprises! BEB Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted March 5, 2018 Share Posted March 5, 2018 BEB: I totally agree with your comments above, especially regarding "Companion". However, when you are making adjustments on the field - as I was - you probably won't have access to it! That's one thing about helicopters - whilst with experience, it is often possible to get a "ball park" set up on the bench, as soon as you get to the field, you find yourself "fine tuning" things quite a bit more than with a fixed-wing aircraft. Even with a governor on the motor, there are too many other variables to predict exactly what head-speed will best suit a particular model. Trimming a heli is not just about getting it to hover or fly straight, but also adjusting the head speed for optimum characteristics for each flight mode - hence the necessity to fiddle with curves on the field, and the potential risk! However, like many things, its only a problem if you are not aware of the issue! Once you know about it, there are steps that can be taken to eliminate the problem - hence my warning! Have fun! -- Pete Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 5, 2018 Author Share Posted March 5, 2018 A very quick update! I have had to walk away from the helicopter as I was about to pick it up and hurl it across the room!! Fitting the main gear: 1. You align two holes in the bearing sleeves in the main and tail-drive gears. Done that 2. You place this in the helicopter, without distrubing that alignment. Not easy but did it. 3. You now insert the main shaft, down through the two bearings in the bearing plates and through the hole in the main/ tail gear assembly. Fiddly but OK. 4.Holding the gears, rotate the main shaft so the hole through that aligns with the holes in the gear assembly. Done that. 5. Inset a 2mm bolt through all that. Almost impossible - but somehow managed it! 6. Stick a nut on the end of the bolt. Absolutely flamming imposible!!! One and half hours I have tried!!! Grrrrrrrrr!!!!!!! I'll take a break,....and try again. I feel better just having had a good rant about it , thanks for listening! Back later! BEB Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted March 5, 2018 Share Posted March 5, 2018 Cue lots of 'helpful' suggestions involving everything from magnets to zen meditation! Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted March 5, 2018 Share Posted March 5, 2018 Blue tac, plus lolly stick, plus nut on the end Edited By Denis Watkins on 05/03/2018 15:21:47 Quote Link to comment Share on other sites More sharing options...
simon barr Posted March 5, 2018 Share Posted March 5, 2018 I bet you'll find that when you go back to it, that nut will go on in one....! Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 5, 2018 Author Share Posted March 5, 2018 No it didn't! All day - no joy! Thanks for the suggestion but I've tried blu-tack, lolly sticks, tweezers, needle nose pliers, sticking it on the end of a hex driver, and many, many, more. All to no avail - I just end up time after time with the nut fallen into the helicopter and me having to shake it to get it out. I think it might be possible with a M2 nut spinner. I stress might - but its the best I can think of. Te trouble is, the smallest nut spinner I have is M3 - of course! So, I've ordered a M2 nut spinner from RS - might come tomorrow - if not day after. I'll move on to the boom while I am waiting. If that doesn't work I think I'll have to resort to black magic! BEB Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted March 5, 2018 Share Posted March 5, 2018 Nut runners are a must have, so are ball link pliers, enjoy flying heli, hate building them. You'll enjoy once you're up n running BEB, the first circuit's a real buzz. Quote Link to comment Share on other sites More sharing options...
Mike Blandford Posted March 5, 2018 Share Posted March 5, 2018 Any possibility of putting the bolt through in the opposite direction? Mike Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted March 5, 2018 Share Posted March 5, 2018 Posted by Biggles' Elder Brother - Moderator on 05/03/2018 17:39:03: No it didn't! All day - no joy! Thanks for the suggestion but I've tried blu-tack, lolly sticks, tweezers, needle nose pliers, sticking it on the end of a hex driver, and many, many, more. All to no avail - I just end up time after time with the nut fallen into the helicopter and me having to shake it to get it out. I think it might be possible with a M2 nut spinner. I stress might - but its the best I can think of. Te trouble is, the smallest nut spinner I have is M3 - of course! So, I've ordered a M2 nut spinner from RS - might come tomorrow - if not day after. I'll move on to the boom while I am waiting. If that doesn't work I think I'll have to resort to black magic! BEB Where's Maplin's when you need em'? Have you tried a longer or different M2 bolt? Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 8, 2018 Author Share Posted March 8, 2018 I'm back - after 5 days to sort this problem with the troublesome M2 nut on the main gear out! OK. I order an M2 nut runner from RS - it arrives next day - free delivery - excellent! I open the package,....its a hex key I double check the webpage, it clearly says "nut spinner" - I check that I ordered the right item - I did. Only it's a hex key, Grrrrrr! I mean its a very nice hex key, and while I do have M2 hex keys I keep this one, because its so nice. But its not a nut spinner. OK, order again, this time from someone I can talk to on the phone. "Is it definitely a nut spinner?" "Yes" "Do you have it in stock?" "Yes". So off we go. It arrived late yesterday afternoon - and it is indeed a nut spinner! I decided to wait to today to have a go. Tried it this afternoon,....... No use, it won't work! You see if I lift the tool so that the hole in the nut is in line with the bolt thread then the shoulder of the nut spinner fouls the gear! You can't get it in there. Damn, So, I went back to what I was trying before. Start - Insert the bolt - but not quite all the way through. Take some tweezers and drop the nut into the right area. Take a suitable "poking tool" and manoeuvre the nut to the recess. Now try to push the nut into the recess with an oversized hex key. If you manage this, hold the nut there firmly with that hex key, take another hex key, the right size for the bolt. Put this in the drive hole of the bolt, so you now have a hex key either side of the gear. Now the crucial bit, call your wife and ask her to hold the helicopter steady whilst you try to tighten all this up. It will then all flip apart, the nut will fall and you will say some very naughty words.Return to "start" above. Eventually - I struck lucky! Here it is, finally in place, thank God! I reckon that has taken about 9 hours of effort - just to get that nut in. But it wasn't going to beat me! (Or so I'm told I have been muttering in my sleep!) What else have we done today? Not much but I have installed the "rudder" servo. Again this is a provided item with the kit - which is good because I believe tail servos on heli's have to be very fast - but of course how fast is "very fast"? Well that depends how much money you want to spend I suppose. If like me you are new to heli's it's handy to have the servo selected for you at this stage I think. Here is the device in question along with its mount: And here is a picture of it installed in the mount:and with its ball link: That mount screws neatly into the back of the helicopter like this: (If you are having trouble orientating yourself in that picture the heli is standing on its nose with the UC towards us and the back end, with the tail servo in it, is facing upward.) I was a bit concerned that once this servo was in place I would not be able to reach the GPro flybarless unit to plug in the servo leads. But I really should have more faith in Align's design skills as the photos below show, access is tight, but it is there. First looking from the side we can see the servo connecting pins on the GPro through the cut-out . Then, looking from underneath, passed the tail servo, we have another access point: It won't be easy getting the servo leads and the S-Bus lead from the Rx in there - but it looks do-able. In fact it looks a piece of cake compared to that nut!! That's it for today then, next the tail boom beckons! BEB Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted March 8, 2018 Share Posted March 8, 2018 Great perseverance, BEB. It's traditionally about now that you discover a reason, not hitherto apparent but in hindsight blindingly obvious, that the nut needs to come off again! Quote Link to comment Share on other sites More sharing options...
David P Williams Posted March 8, 2018 Share Posted March 8, 2018 Well done BEB. You did get thread lock on the nut didn't you Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 8, 2018 Author Share Posted March 8, 2018 Threadlock! I knew I'd forgotten something!!!! Noooo, seriously, it got a double helping. I tell you that nut is never coming off - I don't care what the need is - I'll disassemble the whole rest of the helicopter first! BEB Edited By Biggles' Elder Brother - Moderator on 08/03/2018 18:13:36 Quote Link to comment Share on other sites More sharing options...
Martian Posted March 8, 2018 Share Posted March 8, 2018 you could of course super glued the nut to your finger then get your wife to spin you round. As for the tail boom is the tail rotor belt driven it is oh dear oh dear how many hands have you got can you stand on your head I will pray for you brother Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 8, 2018 Author Share Posted March 8, 2018 Hi Martian, no the tail rotor is shaft driven, yes I have heard a few horror stories about putting together belt driven tail rotors! Well, let's see what its like. It doesn't look too bad - but then you could have said that about installing the main shaft. BEB Quote Link to comment Share on other sites More sharing options...
Devcon1 Posted March 8, 2018 Share Posted March 8, 2018 I seem to recall the said item is sometimes called the "Jesus" bolt. I wonder why ? Quote Link to comment Share on other sites More sharing options...
Dwain Dibley. Posted March 8, 2018 Share Posted March 8, 2018 I used to use blue/sticky tac on a lolly stick to hold the nut.......then side cutters to hold it whilst tightening it. The good new is Thunder tiger helis had a nut holding moulding in the gear. The secret to the belt drive is the 90 Deg twist, and getting it the right way first time. D.D. Quote Link to comment Share on other sites More sharing options...
Barryorbik Posted March 8, 2018 Share Posted March 8, 2018 Devcon 1 a slight correction as the Jesus bolt is actually the one which holds the main rotor head block to the main shaft and if you have a look on Youtube and search for "Jesus Bolt Helicopter" there is a video of an American guy who either forgot to put his Jesus bolt in or it fails on hos Raptor 50 - its with amusing but the outcome could have been very serious. Barry Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 9, 2018 Author Share Posted March 9, 2018 A "Jesus Bolt"! I like that, it seems very fitting; but although it was probably one the words I used to describe it, it almost certainly wasn't the term most frequently employed! I have been out most of today, so not a lot has been done, but still every little counts! What an exquisite bit of engineering,.... It is of course the tail rotor unit. Like most engineers I suspect I'm fascinated by things like this and can spend silly amounts of time just moving the ball link backwards and forwards and admiring how clever the mechanism is! This unit comes pre-assembled, but all of the screws are only loosely inserted. They need to be taken out, a little thread-lock applied (taking care as to not get it on bearing and articulated surfaces - or we'll gum the works up!) and then reinserted and tighten up. There are a lot of very small screws in that mechanism, this all takes a considerable time! I was careful to remove just one screw at a time - I am sure there are bearings and spacers and washers in here that I don't want to all fall out into random heap on the bench! I don't need a 3D jigsaw puzzle! I am enjoying the build but there are a lot of screws - most of them very small! I am reminded of the idea that a helicopter is just 10,000 screws flying and close formation! Now for something very exciting! The first aerodynamic bit!!! As a flying plank recidivist its nice to handle a "wing" again! So here's the tail rotor in place: Nice. BEB Quote Link to comment Share on other sites More sharing options...
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