Martin Harris - Moderator Posted December 11, 2024 Share Posted December 11, 2024 While the tone of one of the posts could be described as sensationalist, I’m sure that it was intended in good faith to illustrate the importance of proper materials and techniques - things which we now know that you are very aware of - but this was not obvious from your previous posts. In fact, I agree with your assessment of gluing requirements for balsa joints where the deeper the penetration the better. One great advantage of posting builds and questions in forums is that experience can be shared. In the case of crimping, it’s quite true that commercial crimpers using properly designed fittings work well but experience tells me that crimps made from randomly sized tubing applied as in your photo often slip. I have yet to see the “third pass” method fail. You are free to ignore this unscientifically proven advice but it’s given in the spirit of trying to help fellow modellers avoid a problem which has been observed many times. Please don’t let some well intentioned advice come over as criticism - this forum is a place for mutual help and appreciation. 2 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted December 12, 2024 Share Posted December 12, 2024 On closed loop connection once happy with them I also run some thing Cyano it them as belt and braces. Quote Link to comment Share on other sites More sharing options...
Declan Posted December 12, 2024 Author Share Posted December 12, 2024 4 hours ago, Engine Doctor said: On closed loop connection once happy with them I also run some thing Cyano it them as belt and braces. I had done the same myself, as you say, belt and braces. I just didn't mention it in the post. Quote Link to comment Share on other sites More sharing options...
Declan Posted December 13, 2024 Author Share Posted December 13, 2024 I'm nearly finished with the covering, just one wing to go. The covering film was purchased from 4Max and I've found it to be really easy to use and good quality. I'm quite pleased with how it looks. The model is now at the 'light at the end of the tunnel' phase. Normally when I'm building something the finishing is a long way off, at least in my mind anyway, but then the finish line sort of creeps up and all of a sudden it's nearly finished. I don't know if anyone else has this feeling or maybe it's just me. I have some time off over Christmas so If I can get it flying over the holiday period that would be fantastic. 5 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted December 13, 2024 Share Posted December 13, 2024 Looking good 👍 1 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted December 13, 2024 Share Posted December 13, 2024 I find covering never ending. Tip, wing panels are a lot of covering, don’t take long, intersperse them with elevators, airerons, just a few off cuts, but seem to take just as long, 1 Quote Link to comment Share on other sites More sharing options...
Declan Posted December 13, 2024 Author Share Posted December 13, 2024 I tend to do the small stuff first while I have the most enthusiasm. The big stuff at the end always seems more fun to me especially the wings when you give it that final shrink and it pulls tight over the structure. 1 Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted December 13, 2024 Share Posted December 13, 2024 Or in my case, burn a hole in it!! 😮 Quote Link to comment Share on other sites More sharing options...
Declan Posted December 14, 2024 Author Share Posted December 14, 2024 (edited) Covering finished! Happy enough with the outcome. The odd error here and there but nothing too dramatic. I've attached the ailerons to the wings and these wings are quite large, from a chord depth in relation to wing length point of view. So just not much more to do now. My next project has arrived (Warbird replicas Me110) so it would be good to get this build finished. I have really enjoyed it so far and it's gone together quite nicely with not too much modding required. Edited December 14, 2024 by Declan 4 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted December 15, 2024 Share Posted December 15, 2024 I might have to think about one of these for 2025 ....... with an oily thing on the front of course 🙂. 1 Quote Link to comment Share on other sites More sharing options...
Declan Posted December 17, 2024 Author Share Posted December 17, 2024 So having finished the model as prescribed I've now put all the radio equipment and battery in place. Achieving the CofG proved to be impossible with the electric motor, prop and battery fitted. The battery was as far forwards as possible. I know my flying skills are not good enough for flying this model overly tail heavy. This seems to be normal with expereinced 3D flyers I think to allow easier hover maneouvers, etc. I'm definately not there! Testing what I need to achive CofG in this setup it turns out that a virtually full Vallejo Paints 200ml surface primer was about right. This is quite a lot IMO so I decided to move the motor forwards by 2" and I've built an extension for this purpose out of wood. I think constructed as standard the CofG with a nitro engine would be fine due to the extra weight and lenghth of one compared to the electric motor. The new motor mount will also give me a convienent ledge to mount any extra weight as far forwards as possible on the model. While I'm at it I'm going to add an extra ledge for the battery to tidy up the front compartment. This will allow me to change batteries easier between flights and I can place the ESC neatly under the new ledge to keep it out of the way of the battery. 1 1 Quote Link to comment Share on other sites More sharing options...
Benny Posted December 17, 2024 Share Posted December 17, 2024 That's a cool idea with the engine. I think this model will be more balanced and easier to drive. 1 Quote Link to comment Share on other sites More sharing options...
Declan Posted December 17, 2024 Author Share Posted December 17, 2024 (edited) The extended motor mount has now been made and fitted. I'm bolting this onto the firewall with 6mm nuts and bolts, don't think it will go anywhere. I'm choosing the large bolts option only (no glue) for weight addition and it gives me the option to remove it easily should I opt to fit a nitro engine at a later date. First impressions are that the motor being foward by 2" gets me closer to the ballpark in relation to CofG. Once I've fitted my exra battery tray I'll fine tune with some lead if necesssary. I do have to replace the undercarriage as the standard one fitted doesn't allow me to swing the 13" prop for the recommended setup by 4Max models. The motor, spinner and prop combo looks fantastic and I think it will be a great performer. I know very little about electric motor selection and specification so I'm more than happy to go with the recommended setup. Nitro selection and prop matching seems much easier IMO! Unfortunately when I was covering the motor block I forgot that the recess for the motor wires is on one side and the block must be fitted in a certain orientation. I should have put the heatshrink join on the bottom! Edited December 17, 2024 by Declan 1 Quote Link to comment Share on other sites More sharing options...
Declan Posted December 20, 2024 Author Share Posted December 20, 2024 (edited) It's funny how when you change one thing it always has a knock on effect on other things. The wires for the motor joined to the ESC just at the point of entry to the fuselage after the motor extension. So I've had to pull the ESC forwards and heat shrink the joint and then fasten the wires externally. Internally I've made up a battery tray to sit above the ESC which is now flat on the floor of the front compartment. I've also added the lead tyre weights under the ESC for balancing. It took 165g of lead to make the model balance. I was tempted to fix the lead externally on the extended motor mount but this would have looked messy I and the risk of the lead coming off would have been an issue I think. This final part has taken a few evenings to sort out but I think I'm there now. Ultimately I'm only going on the instructions for CofG so I won't know how it balances until I fly it. I really need to finish this model now so that I can start the Me110. I've only got to tidy up the radio installation, set up the throws and fit the larger undercarriage. Edited December 20, 2024 by Declan Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted December 21, 2024 Share Posted December 21, 2024 Would be worth inserting some some very dense foam or balsa block where the nuts come through the bulkhead, just in case it meets the ground harder than anticipated. Once the lipo has physical damage they can become problematic (hope that's not too sensational, but they have been known to catch fire). PS In general its not a good idea to insulate the ESC (device that produces a lot of heat) with foam. Held in place with a cable tie wand plenty of air flow is good. Quote Link to comment Share on other sites More sharing options...
Declan Posted December 21, 2024 Author Share Posted December 21, 2024 (edited) Chris, yes a good point with regards to the bolts for the engine. I do have a lump of foam I will shape to fill the front space. The foam for the ESC was removed as it wasn't necessary once the battery tray went in. Again, fair point with regard to the heat. I do have a cutout on the bottom of the fuselage for airflow but I might add another. TBH it's been quite a challenge to fit everying in place. I'm mindful of the battery ESC positioning with regards to regular intallation/removal of batteries while flying at the field and not in ideal workshop condiitons. I think I have it so that changing batteries shouldn't be too much of a fiddly struggle. The model itself has so little length in front of the CofG it's quite an electrical challenge to fit everything in as far forwards as possible. There is quite a lot of room under the main spar but the weight addition requirement penalty would have been too great. I think nitro would be far easier to install and balance. On the battery front I'm not sure where my opinion lies as yet as I'm too new to the use of lipos in general. Agreed they can be very dangerous and catch fire, especially when damaged and being charged, no dispute there. However, I've also read comments/opinions from professional drone operators who say some of their batteries are like 'pillows' and they still use them. I do have one battery that I use (but acturally store outside in my BBQ) that is a bit soft. I charge it outside and I'm kind of using it as a study. The risk I assume is that one day it might 'bite' so to speak and if that was while being transported to the flying site in my van that would be bad. Although, the risk of fire is generally while being charged, or having just been charged, is the correct? I don't have enough personal experience and opinion in the hobby can be quite varied. Given the millions of lipo batteries that are shipped uncerimonioulsy around the globe in aeroplanes and container ships without issue they may be fairly safe, even if not in ideal conditon. My soft battery arrived to me already soft but it was so cheap on Bangood it wasn't worth sending back. My last battery investment was with 4Max and they all look perfect BTW. So I'm not quite sure where I am on the lipo safety procedures spectrum! Any thoughts would be welcome, even the sensational ones. 😉 Edited December 21, 2024 by Declan Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted December 21, 2024 Share Posted December 21, 2024 4-Max is a good supplier, Declan. Whilst not the cheapest on the market I can testify they are durable and have a long life. I use them as my go to supplier, as an example I have had some 6000 mAh 6s jobs at least 3-4 years and they are still hard to touch despite some abuse at times. Just as an aside I probably would discard lipos safely if they show any signs of ballooning. It's just not worth the risk. Nice build by the way - I also feel your pain trying to "fit a quart into a pint pot" when fitting out smaller models. Quote Link to comment Share on other sites More sharing options...
Declan Posted December 21, 2024 Author Share Posted December 21, 2024 3 minutes ago, Adrian Smith 1 said: 4-Max is a good supplier, Declan. Whilst not the cheapest on the market I can testify they are durable and have a long life. I use them as my go to supplier, as an example I have had some 6000 mAh 6s jobs at least 3-4 years and they are still hard to touch despite some abuse at times. Just as an aside I probably would discard lipos safely if they show any signs of ballooning. It's just not worth the risk. Nice build by the way - I also feel your pain trying to "fit a quart into a pint pot" when fitting out smaller models. Adrian, yes I discovered 4Max only recently and I've found them to be very helpful and with a good selection of quality products. I've purchased quite a selection of items and I've never been disappointed. I probably will dispose of the 'soft' lipo, now I have a supply of 4Max batteries. Lol, I am just keeping it for curiosity/study value at the moment. Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted December 21, 2024 Share Posted December 21, 2024 20 minutes ago, Declan said: Lol, I am just keeping it for curiosity/study value at the moment. Pretty boring unless it explodes/combusts......... which is what you don't really want to happen 🙂 1 Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted December 21, 2024 Share Posted December 21, 2024 How puffy is too puffy is not really a measure of lipo condition or if its about to fail (generally they just give up rather than catch fire). So just keep using them until you notice performance is declining (or when the total capacity has dropped by 10%, but you need to know what the original capacity was, not what is stated on the side of the lipo). This is quite easy if you are giving the lipos a hard time e.g. edf or flying the Cougar hard. IMO I have found the cheaper lipos are ok if you are using them in light load applications (e.g. high wing trainers) where only a small percentage of the C rating is actually used. Worth reading George's (4-Max) comments regarding lipo performance and voltage sag and as a observation I have found that Purple power lipos don't tend to puff. I have been using GNB lipos from Hobby RC, they perform very well in tough applications and are generally slightly larger capacity for the same physical size + slightly lighter (handy if you go the next capacity up and its the same weight). GaoNeng - GNB Batteries | HobbyRC UK PS the original Cougar had a single wing so no spar to get in the way + if you had made a motor extension box (with door) you could have put the lead in there to give yourself a bit more room. On the subject of battery fitting, I appreciate comments made by our safety officer regarding connecting batteries from behind the prop or always maintaining your arms away from the prop arc at all times. Personally I prefer model benches that restrain the wings ( like the IC benches) or have the tail restrained with a ground anchor. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted December 21, 2024 Share Posted December 21, 2024 I bought one pair of 5000 mAh 6s GNB lipos that I used in series (12s) and unlike any of my other paired brands of lipos, their discharge rates were appallingly mismatched. After each 6 minute flight one lipo's 6 cells showed 3.81v per cell while the other consistently showed the 6 cells at 3.66v per cell. Not happy with that I am afraid. Overlander, 4-Max, Topfuel and even Turnigy Nano-techs all displayed consistently matching discharge rates when wired in series. Whilst I acknowledge what you say, Chris, about puffy lipos the safety instructions on my Overlander lipos are quite explicit " "stop using or charging a battery immediately whenever the battery is .......... deformed or starts to balloon, swells up ....." There is all sorts of warning about failure to comply with instructions with the worst possible case being fire or explosion. I think that's clear enough for me not to takes risks IMO. If you are new to this game Declan, please be warned and cautious. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 21, 2024 Share Posted December 21, 2024 2 hours ago, Declan said: Although, the risk of fire is generally while being charged, or having just been charged, is the correct? Yes, highest risk is when charging and immediately after. (Or when being abused via discharge) Quote Link to comment Share on other sites More sharing options...
Declan Posted December 21, 2024 Author Share Posted December 21, 2024 A manufacturer is always going to advise on the possibility of a worst case scenario, they have to. Otherwise they'd be in court paying fines for incorrect instructions or advice in the event of a fire. However, in the real world what is the actual experience everyone has with these batteries? Yes fire and explosion is possible but that doesn't necessarily mean they're dangerous in the main. I'm not advocating a complete abandonment of safety advice or disagreeing with anything said before but merely looking for the discussion. Driving can be dangerous, people die on the roads all the time, yet no one advertises that they've stopped driving because it's dangerous. On a separate note, risk and self assesment are part of a full and exciting life. If we all did what was completely safe life would be pretty boring. Probably a discussion for a different thread......😉 1 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 21, 2024 Share Posted December 21, 2024 Lithium cells burn pretty darn good. Deformation / puffing indicates some gas has been released at some point. Might be low quality manufacture, might be damage. The batteries I have dealings with in professional capacity are lithium and the end user / manufacturer has zero tolerance for any has discharge or deformation. Make of that what you will. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted December 21, 2024 Share Posted December 21, 2024 In this particular case Declan, I think it's good advice to follow instructions. Are you willing to take the chance? I am not. I am sure any discussion with your insurer after the event will be less that sympathetic. This forum has quite a few examples of posters experiencing fires and at least one with horrific results. Feel free to RA and do what you think best. I just think in this case it's one risk too many. That's all I will say on the matter. Quote Link to comment Share on other sites More sharing options...
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