Chris Bott - Moderator Posted October 20, 2010 Share Posted October 20, 2010 I've just been speaking to Danny, he's currently (pun, sorry) soldering up another 8S pack so he can test 8S2P tomorrow. I think we'll have to wait a little longer "Direct orders from Group – Park himself. " Edited By Chris Bott on 20/10/2010 21:08:07 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 20, 2010 Author Share Posted October 20, 2010 Tomorrow!!! I am waiting for one cell to charge and I will get some numbers tonight lol... I was pleased/surprised at the difference between 7S1P and 7S2P nearly 400 watts increase. So I am really curious to see if 8S2P really pushes the power up. "At ease men....." whoops Dad's Army......... Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 20, 2010 Author Share Posted October 20, 2010 well the scores on the doors are very interesting. Going to 2P seems to really help A123 maintain there voltage under load. a 22" prop should see us over 1500 watts Tally ho Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 21, 2010 Author Share Posted October 21, 2010 Still pondering over the power source for this........Being a big advocate of A123 makes it really difficult to go down the LiPo route. But I have to be practical here. An 8S A123 pack will be £100 and because it is 2P then that will cost £200. More sums for those that are interested: 5065 motor + 5S + 2S LiPo = 1383g 5065 + 8S2P A123 = 1720g sc 120 + fuel + lead = 1954g So you can see even with A123 the model will still be lighter than a fully fuelled IC and with LiPo lighter still. I am happy with the motor choice, the reason I am pondering the cells is I have to design the battery box before I can start the build........ "Contact!" Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted October 21, 2010 Share Posted October 21, 2010 I'd be trying to design a battery box to accommodate both types of battery I think. Is that possible? Even better would be to make it so the cells are easily removable so they can be used in other models too. Especially considering the cost. Don't forget A123's will last as long as a number of sets of LiPo's when considering the costs. "Tally Ho.." Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 21, 2010 Author Share Posted October 21, 2010 Hi Chris, In a perfect world I agree. But in this instance I can see a couple of problems with making the box useable by both types of cells. Firstly if its A123 I will have to accomodate 4 seperate packs, combined to make 8S2P. For lipo I would also have to combine packs but only two. The shape of the packs I have available are not really similar so this may make a universal box as in my Chipmunk more difficult. The second problem is that Tony has designed the lower section of cowl to be detacheable. This means if the cells are to go in and out at that position the model will have to be turned over for easy access. Again A123 would not make this such an issue. I could make the top cowl section removable but it pulls me away from Tony's original plan which I would like to follow if I can. I will draw some lines and see what i can do "Septic calling Sappa......." ooops Angels One-Five...... Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 21, 2010 Author Share Posted October 21, 2010 The flash gun has expired so sorry about the pictures, but I think you get the idea. Most of this box is from 3mm lite ply with a bit of heavier 1/4 birch thrown in. You will notice that I am removing almost all of the inside area of the thick heavy 12mm birch ply bulkhead, thats a pound saved on its own "Squadron Scramble!" Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 21, 2010 Author Share Posted October 21, 2010 10 minutes and the bandsaw and bench sander had the component parts ready for assembly. The sides and main bulkhead are birch ply the top, rear and buttresses are from lite ply. Tally ho! Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 22, 2010 Author Share Posted October 22, 2010 A little more progress, the parts are ply and tend to be a little curved so forgive the appearance of gaps everywhere. These parts are NOT glued just dry fitted to check that I haven't made any glaring mistakes. Once glued and clamped the gaps will close up. You can see there is not much left of the centre of that 1/2" Birch ply bulkhead. "make angels ten blue squadron" Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted October 22, 2010 Share Posted October 22, 2010 Nice one Danny that looks a great start. A long way down page 5 of the build thread and we have something to see "Why don't you cut out the clowning?" Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 22, 2010 Share Posted October 22, 2010 Nice work there Danny boy.... Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 22, 2010 Author Share Posted October 22, 2010 Thanks Tim, Chris are you intimating that I may be all talk? long way down page 5 and still the glue bottle is shut You ought to see my Hurricane thread on RCSB 73 pages and still no sign of paint I go for quantity not quality "Don't just stand there, get the glue open!" Quote Link to comment Share on other sites More sharing options...
Herri Posted October 22, 2010 Share Posted October 22, 2010 Neat Danny. Will there be access from the cowl? Which battery combination did you base your box on? Cheers Herri Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 22, 2010 Author Share Posted October 22, 2010 Hi Herri, as you will no doubt know I am probably the most indecisive modeller on the planet if not the entire universe. So as Chris suggested I have covered almost every eventuality. The box will take up to 20 A123 cells. It will also take up to 14 5000 cells (made of a 5S and 2S). I have the option of leaving the front of the box open for lipo access through the cowl, or the back to install the A123 for access through the wing. Versatile eh? I like to think thats why I spent so long pondering the layout well that's my excuse....... "Reserver?" Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 23, 2010 Author Share Posted October 23, 2010 I am sorry If this is obvious to most, there may be the odd person that is interested to know how to transfer the lines on the plan to a three dimensional object you are trying to create. Here I am using engineers squares at strategic points on the plan to project vertical lines to help align the component parts. If you get this bit wrong then your thrust lines wont be right...... Still no glueing has taken place Quote Link to comment Share on other sites More sharing options...
Stephen Grigg Posted October 23, 2010 Share Posted October 23, 2010 With all this care ,thought and patience you put into building a Model Danny,do you find the end result means there is less trimming and no surprises when the model takes to the air? Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 23, 2010 Author Share Posted October 23, 2010 Hi Stephen, I don't think it can hurt. It is very sattisfying when a model requires very little trim, and yes it does make that first flight a little less daunting. Thrust lines, wing incidences, tailplane incidence and in line with the wing, upright fin, and of course equal and correct amount of washout and C of G are all things we can control. I am never more worried about a test flight than when its somebody elses work. They are the ones that usually see the model leap of the ground prematurely veering one way or the other. An Se5a I converted to electric a couple of years ago, was just such a beast. It took several scary test flights and work with an incidence meter, before I tamed all the incorrect incidence and twisted wing issues with that one. Still it gave the other club members some fun watching me cavort about the sky Cheers Danny Quote Link to comment Share on other sites More sharing options...
Stephen Grigg Posted October 23, 2010 Share Posted October 23, 2010 Quite recently I repaired an Extra 300S and glued the 2 halves of the fuselage together,followed by strngthening braces to the joins.I awoke at 6 am the next morning realising I was a sixteenth of an inch out on one side because Id fitted a strengthening piece of ply on that measurement on one side.Didnt make any difference when I flew it. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 24, 2010 Author Share Posted October 24, 2010 This is embarrasing, bottom of page 5 before any glue is involved But finally we are away.... kind of... Not really happy about overlapping the plan. But having said that the joins are easy to spot. You can see that the laser didn't quite cut all the way through in some places, but this was only a minor inconvenience The front sections of the RHS dry assembled for fit The one to look for here is the wing seat section. It is very badly warped. In fact using every pin I had to hold the section as I teased the section straight ended up cracking the wood. But I did at least get it straight, not sure how much stress is bottled up in doing this mind you You can see by this shot that the laser cutting is a little short of the bulkhead. I checked both the free set of plans and this set that came with the wood pack and they both concur that somethings wrong lol You can also see that the sides are not quite tall enough either..... I have used Titebond as this has good gap filling properties. The wood is going to have to be wrapped around the fus and its 1/4 balsa with joints. I think I may have to get the amonia out to curve this lot. I also managed to get a little done on the battery box/motor mount. It is not something you can just glue together you have to assemble it a bit at a time waiting for epoxy joints to dry before moving on to the next bit. "grow up Jamie!" Edited By Danny Fenton on 24/10/2010 23:41:19Edited By Danny Fenton on 24/10/2010 23:50:52 Quote Link to comment Share on other sites More sharing options...
Al Knights Posted October 25, 2010 Share Posted October 25, 2010 Your problems with the wood and plans, would surggest that RCM&E management needs to go back to the suppliers and have a few words over the quality issues you have highlighted Danny. (I hope you take note Mr Ashby ) Other than that...it looks OK Danny....still watching. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 25, 2010 Author Share Posted October 25, 2010 Hi Alan, it may just be that I have had the wood laying open for a couple of weeks. I will check the blank that the troublesome section came from. Building a fus side up from many pieces is fraught with problems. However the wood is nice and light, which is great. The top of the fus is built slightly oversize to get planed flat before the the top strips are added, so it wont be too big an issue. The front section being cut short, just needs some scrap 1/4 stock to infill. It will be okay. It is worth noting the cut kit uses 6mm throughout for the side sections. On the plans the upper parts are 4mm and the lower 6mm. You have to be careful to make the inside faces flush, this means making the rhs over a LHS side view. You will have to use yout imagination as to how to achieve that with it all being 6mm that problem is averted. "For gods sake Jamie, give your brain a chance" Cheers Danny Quote Link to comment Share on other sites More sharing options...
Herri Posted October 25, 2010 Share Posted October 25, 2010 Thats annoying Danny. Upto now I have only found one piece where the laser cut was slightly out. Luckily its on an edge that will be sanded anyway. What with that and the plan issues I'm pleased I bought my bits where I did. I see you are getting into metal working. Do you ever sleep? Cheers Herri Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 25, 2010 Author Share Posted October 25, 2010 Sleeping what's that? I have just had a quick look at the sheet that the offending side piece came from and it is straight. So I am not sure how it became so bent in the hour from removing it from the sheet and trying to fit it. I think it may just be a one off. The wing and tailplane seats are nice and true, thats the most important bits. The lasercutting is is perfectly true/perpendicular on the edges which is good. I have wanted a lathe for years, but never could justify one. I still can't tbh "who the hell's he trying to kid?" Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 25, 2010 Author Share Posted October 25, 2010 You may get bored with all these updates sorry about that, but perhaps it may help somebody. here is the RHS removed from the board and the joints sanded with a long Permagrit. The fus side is sanded carefully to a line marked 6mm back from the bulkhead face onto the fus side. There we have a corrected side. Perhaps it should be right, but it is not difficult to correct and to be honest due to temperature changes the plan and parts can sometimes be different. Now I will add the doublers to try and combat it all warping again, it has already taken on a bow, perhaps from all the force I used to bend that lower section straight.... should have cut another "It's no use, they will be here in half an hour, we must leave immediately" Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 25, 2010 Author Share Posted October 25, 2010 Okay so thats my first error. Not a good start really. In my excuse I have never built a Nijhuis design and am used to building to a plan. Tony has a different length for the RHS and LHS the RHS is shorter than the LHS shown on the plan. I do remember reading this and the light suddenly came on so appologies to Myhobbystore the fus length probably was right "Where to sir? Why don't you follow me and find out!" Quote Link to comment Share on other sites More sharing options...
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