Ben Mullins Posted October 21, 2009 Share Posted October 21, 2009 '250ft Inverted over water' Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 21, 2009 Author Share Posted October 21, 2009 Absolutely Ben, These russkies wouldn't want their oppo's spotting them from above as they high-tailed it across the Baltic now would they.... Quote Link to comment Share on other sites More sharing options...
David E Posted October 21, 2009 Share Posted October 21, 2009 Posted by TonyS on 21/10/2009 20:31:43: It was definitely the colour and nothing to do with me being a rubbish pilot Hehehe Yeah, I wasn't meaning that you shouldn't paint it in the Yak 17 scheme, just that there's no point being too anal about the colours I've noticed that none of the model eurofighters I've seen use a scale colour scheme. I imagine the light grey on the real things is rather too effective!! Be interested to see how it turns out, whatever colour scheme you go for in the end. Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 24, 2009 Author Share Posted October 24, 2009 OK, Back again. My 125A Castle Creations ESC arrived today. This has caused me yet more weight woes. Sadly, although advertised with a BEC, the BEC must be disabled if you are using anything over 3 cell LiPos. As I need 4 cells to get the thrust out of the Wild Beast this means I now need a sep receiver battery pack... More weight! Anyway. I've wired it all up with 6mm gold connectors all round, fitted the fan and frightened myself witless. If anyone has ever held a fan unit with a Wild Beast motor running in it you'll know what I mean. There's something insanely maniacal about it .... I can imagine if you crossed the devil with a thousand dentist's drills and then put him in a bad mood this is close to what you'd get. The exhaust jet removed the contents of my workbench to the other side of the room in short order. As I know it all works though I can now get on with planking the last bit of the wing section so, without further ado..... (back later) Quote Link to comment Share on other sites More sharing options...
Dusty Posted October 24, 2009 Share Posted October 24, 2009 Tony you going to need alot of venting to keep the electrics cool! That setup is going to be pulling like a 100amps? Making some sort of venting to keep the beast cool as well as lipos will shread weight, might kill some scale looks but you not going to notice the holes when its flying! I hope you going to bungee the model first? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 24, 2009 Share Posted October 24, 2009 Why not use a UBEC - much lighter than a separate battery. I have one here which is happy on up to 8s Lipo and supplies constant 5A @ either 5 or 6V Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 24, 2009 Author Share Posted October 24, 2009 Timbo, A great idea!! You've cheered me up no end. If you were here I'd hug you (only kidding..) Any recommendations - make, source etc? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 24, 2009 Share Posted October 24, 2009 I got my last lot from H City, but try Rob at Giant Cod. Hows this one Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 24, 2009 Author Share Posted October 24, 2009 Timbo, I know this will sound dumb but how does it connect in to the battery? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 24, 2009 Share Posted October 24, 2009 I just hard wire it to the ESC input leads, that way it powers up and don as the battery is plugged in and out IYSWIM Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 24, 2009 Author Share Posted October 24, 2009 Magic! Only downside is yet another wait until the postman comes......(oh and another £4.50 + postage). The other good news is that I found the right green for the fuse and tops of wings plus a light blue for the underside I hope so we can start adding a little colour soon. Quote Link to comment Share on other sites More sharing options...
David E Posted October 24, 2009 Share Posted October 24, 2009 Posted by TonyS on 24/10/2009 21:08:41:Magic! Only downside is yet another wait until the postman comes......(oh and another £4.50 + postage). The other good news is that I found the right green for the fuse and tops of wings plus a light blue for the underside I hope so we can start adding a little colour soon. That could be a while at the moment Might be worth asking if they can use another carrier? Glad you found some paints. The good news about using a UBEC is that it can reduce the cooling load, as the ones built into ESCs can be quite inefficient and make a bit of heat if they are linear rather than switched. Not sure if the Castle one is switched anyway, though. Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 24, 2009 Author Share Posted October 24, 2009 Good news indeed David as there's precious little air going to reach the interior of the fuse where the ESC lives. The fuse is looking good in its new colours - It's matt paint which I'll spray with satin laquer when the decals are on. On the subject of decals. As I said earlier I was very unimpressed that RBC supplied the kit without the advertised decal set and when chased advised they didn't do the decals any more. They've sent some substitutes which are useless. They're the wrong colour, the wrong sizes and the numbering totally wrong. This is what I received..... What I needed was..... I realise that this pic isn't of the kit but of a different plane however the insignia is pretty much identical. If anyone can help with the decals I'd be really grateful. I can't face having to cut a stack of stars out of Solartrim (it'll be three per decal - one large red, one smaller white and an even smaller red to make each one) a nightmare. A quick pic of the fan and motor housing going on.... Quote Link to comment Share on other sites More sharing options...
David E Posted October 24, 2009 Share Posted October 24, 2009 That is a bit of a disappointment with the decals. It seems bad form to decide you aren't going to supply decals with a kit any more and keep on selling them without some kind of note on the box at least. Are the red stars that they have supplied too small? I would imagine that there would be one on the underside and one on the topside of the wing, too, going from other soviet aircraft. I don't know if there's any mileage in stencils and spray paint? I imagine that would end up incredibly tricky too. I wonder if there's a plastic kit you could borrow some decals from? Might be an expensive way to get them, though, as the kit would need to be pretty large! Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 25, 2009 Author Share Posted October 25, 2009 Hi David, Stencils might work but I can see me having to go down the route of buying a compressor and spray gun and learning another new skill - all for the sake of a sheet of waterslide decals. As an aside, the RBC website still advertises the kit as including the decals !! I'm not sure if there's a service anywhere for laser cutting decals from Solartrim etc - It would be a winner. I know some people with laser cutters - they may be able to cut from drawings - you never know. Another alternative would be to try to print some and glue the paper onto the model then gloss laquer them but I don't think that the quality would be great. Quote Link to comment Share on other sites More sharing options...
David E Posted October 25, 2009 Share Posted October 25, 2009 Just remembered, I came across a guy on a cycling forum some years ago who had a machine that could cut stickers out in quite intricate shapes. I got him to cut some stickers for a bike that I'd built, and it was for a very reasonable fee in stamps. He did it from just a microsoft word file I send him with the text I wanted in a particular font, where I had adjusted the spacing etc. Perhaps if you made a vector drawing in Word he could do it from that? I would make one red star and a white outline to stick on top. You'd need to put a lacquer of some sort on top to keep it in place permanently. Would you like me to see if I can find his details so you can ask if he still has the machine?Edited By David E on 25/10/2009 21:33:46 Quote Link to comment Share on other sites More sharing options...
David E Posted October 25, 2009 Share Posted October 25, 2009 I found the details, so i sent you a PM... Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 25, 2009 Author Share Posted October 25, 2009 Firstly, a big thanks for the suggestions about the stickers. My cousin called by today and he's a whizz with cad and design packages etc. He basically reproduced what I needed to the right scale per the plans and then we've printed out a load of these which I'm using as cutting templates for the red and White solartrim that I had in stock. The results are quite good even if the process is painstaking and slow. Apart from the UBEC I now have everything I need to finish the job except the satin laquer. On the subject of motors etc I put the whole lot together today and tried to open it up. The motor cuts out at 75% throttle which I did find surprising. The ESC specs suggested that if this happens it's because the battery has fallen below the minimum voltage. I think I need to alter the settings from shut off completely to shut down a bit otherwise I'm going to be balancing the throttle at 75% max and praying the motor doesn't switch off. I may set the Tx to max at 80%. With all the plane assembled it shot across the carpet today (into the waiting arms of my helpers) so theoretically it should have plenty of thrust!! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 25, 2009 Share Posted October 25, 2009 Your motor should not be shutting off so soon... this suggests that the batteries you are using are not up to the task, and voltage is sagging unacceptably almost immediately.Altering the ESC to provide "soft shutdown" is only masking the problem. I suggest you monitor the current drawn and voltage held using a wattmeter, or your batteries will have a very short life.I take it you have "trained " the ESC the correct and full throttle throws of the Tx being used ? Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 25, 2009 Author Share Posted October 25, 2009 On the issue of the motor / ESC it does seem odd. I've tried to get as good 'kit' as possible given the motor's high output. The battery is an Overlander Extreme 35C Constant discharge 3,700mAh 4S. I appreciate that batteries don't always live up to their own hype but I've used Overlanders before and not been disappointed (having said that I've never thrown one of these motors at one!)I've used 6mm gold connectors and not lengthened any of the wires between battery and ESC etc. The ESC is a Castle Creations 125A and I was using a separate receiver battery. I received the battery with 40% charge. After messing around today it had 13% left. I'm reluctant to try it on my Wattmeter as I don't think it could handle 100Amps plus. The wires look very thin compared with the motor / battery and ESC and, in any case, I'd need to replace the connectors with 6mm (currently 4mm) or rig up an adapter. Tony PS I should add that the battery and ESC did get quite warm.. PPs What do you mean "trained the ESC...?" Edited By TonyS on 25/10/2009 23:40:11Edited By TonyS on 25/10/2009 23:41:44Edited By Timbo - Administrator on 03/11/2009 09:10:03 Quote Link to comment Share on other sites More sharing options...
TonyS Posted October 26, 2009 Author Share Posted October 26, 2009 Timbo, reflected on your comments about 'training' the ESC. I think I know what you mean and maybe that was where I went wrong. According to the instructions with the ESC you set the throttle to above 50% when connecting the battery THEN power down, at which point the ESC arms ready for flight. Reading further it suggests that you should set the throttle to MAX then connect the battery then put the throttle to min before it arms. This makes more sense as it would then know the extreme limits. I know I set the throttle to about half way btw 50% and WOT when I connected it up. Coincidentally this was where it was cutting out. Hmmmmm. I'll recharge the battery today and go through the sequence once again stating at WOT and report back. T Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 26, 2009 Share Posted October 26, 2009 Yes indeed, thts the "training" I referrred to. Normal procedure is to move Tx throttle to FULL and then switch on the Tx. Then power up the ESC, and then move the throttle stick back to "stop". The ESC/motor emits a beeping tune to confirm its learned the throw. No comment re the battery / supplier. Edited By Timbo - Administrator on 03/11/2009 09:10:27 Quote Link to comment Share on other sites More sharing options...
TonyS Posted November 3, 2009 Author Share Posted November 3, 2009 Now I'm worried chaps. I've painted the model - the green looks stunning but the blue on the underside.... I will have to sand and re-paint as it looks like some kind of comedy kit. (I need better lighting in the cellar where I spray!) The weight really is worrying me though. Using the basic kit and before it was completed, before covering, including the fan, motor, Rx etc etc the model came in at 1200g. Now it's been covered it's weighing in at an obscenely lardy 1490g !!! I'm thinking of sawing the wings off and nailing it to a buggy chassis. I cannot understand how the plans suggest an AUW of 900g to 1200g - this MUST be without batteries. Ton, if you read this please could you let me know what weight yours comes in at given you've glassed yours and fitted it with a LiPo / brushless set-up. I've never glassed a model before but am shocked at the weight it's added. Total weight in old money 3lb 3 oz. Max thrust from the fan (if I can get the max out of it) is stated at 4lb so it should fly - but not for long as it'll be at WOT a lot of the time. Quote Link to comment Share on other sites More sharing options...
David E Posted November 3, 2009 Share Posted November 3, 2009 If you can get 1:1 thrust out of it I don't imagine you'll be flying round at WOT all the time for scale flying, I'd imagine your main concern is going to be wing loading. However, I'm certainly no expert! Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted November 3, 2009 Share Posted November 3, 2009 If you don't connect a Watt Meter to it your committing the first sin of electric modelling! If your pulling 100A out of your brand new battery its not going to last very long, always aim to take no more than 70% of its maximum current rating so that it lasts a long time. For your 4s1p 3700 35C that would be approximately 90A max, which won't give you much running time. I run a similiar battery, 4s1p 3700 30C at 60A in my sniper and I only get 5min with throttle control. Tom Quote Link to comment Share on other sites More sharing options...
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