EarlyBird Posted December 13, 2020 Author Share Posted December 13, 2020 That's all useful information Peter. You are spot on the plans are A1. I had not thought about cutting the plans up to enlarge and copy I am continuing with the preparation of the fuselage by marking the former locations on the inside of both halves. I have checked that the existing hole in F2 will accommodate a 2200 3S battery and was surprised to find that two will fit and even more surprised that a 5000 3S just fits. Lots of choice and no problems. anything else to do that is easy now or harder once glued up. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 13, 2020 Share Posted December 13, 2020 I am amazed at the size of battery that it will take!! I can't think of anything tricky to build on the model. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 14, 2020 Author Share Posted December 14, 2020 Peter your surprise was well founded as they only fit when perpendicular. I was ready to start gluing when as a last check I tried over the plan and found that F1 forces the battery to be installed at an angle and guess what? I put the lid back on the glue pot and gave up in disgust Why did I not think of that before I opened my big mouth? How embarrassing. The sides are marked up and formers are prepared, except F2. Using a method I have seen many times on the forum F4 is being glued. More to come, I hope. I need to check that the battery and ESC will fit or buy an IC engine. Now that's a good idea. Cheers Steve Quote Link to comment Share on other sites More sharing options...
kc Posted December 14, 2020 Share Posted December 14, 2020 Looking at the plan I would expect the hole in F2 to be the limiting factor in inserting the Lipo - perhaps open out the hole 6 to 12 mm higher? That might even allow a slim 4S 3000 to fit if required. I have always thought that if converting an ic model to electric that the engine bulkhead should be moved forward by the difference in length of ic motor plus mount to electric motor with mount. Means the fuselage side needs increasing in some cases by an inch or so, but makes all the difference in CG and also Lipo access. Could be done even now by butt jointing an extra 1.5 inch on and reinforcing with an extra doubler ( trebler) lapping over an inch or more. That would give very easy access to lipo. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 14, 2020 Share Posted December 14, 2020 Posted by kc on 14/12/2020 12:40:55: the hole in F2 to be the limiting factor in inserting the Lipo. Sounds about right, make that hole large enough and you can add a hatch at the top of the tank bay. Lipo can slide backward under the wing a bit? Or, as said, move the firewall forward about 1". Many ways to skin the cat. Quote Link to comment Share on other sites More sharing options...
kc Posted December 14, 2020 Share Posted December 14, 2020 This is what I would ( will ) do to electrify the Swizzle Stick. 1.25 inch extra fuselage length added in both balsa and the ply doubler, and any butt joint covered in a trebler of 1/8 ply to the orange area shown. I like to use a light ply tray with Velcro straps to take the Lipo which also reinforces the engine bulkhead -this is shown in pink up to F2. Beneath the lipo tray is an area for ESC when a hatch is fitted underneath. If using Sarik cut parts then the standard F1 is used and this revises top line and so a tiny wedge of balsa needs to be added to fuselage sides. Edited By kc on 14/12/2020 14:34:41 Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted December 14, 2020 Share Posted December 14, 2020 I got one, Leo 25 power. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 14, 2020 Author Share Posted December 14, 2020 Thanks Guys for the very helpful ideas. I have enlarged the hole in F2 and glued it to the fuselage side. Testing with F1 as designed 2200 3S and 2200 4S fit easily, 2x2200 fit with care, and 5000 3S not a chance. I like the idea of moving F1 forward because of the extra flexibility with battery positioning. I need to make a decision Very smart Paul Jacinth? I like Jacinth especially on dull cloudy days, no shortage of them recently. I was tempted to try IC but I would need help and there is no chance of that while social distancing is in force. Again thanks everybody. Cheers Steve Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 15, 2020 Author Share Posted December 15, 2020 After sleeping on it the decision has been made. I am going to extend the nose as shown by KC. This is based on nearly three years experience of converting and flying electric, not a lot I know. To get the balance correct the motor and battery have to be moved forward to minimise the amount of lead required in the nose, obvious I know. I have done this on the RF-4 by building a motor mount that the battery fits into, I now wish I had done that with the Ballerina and I will investigate if it is at all possible. Not to worry as I have said before every build is practice for the next one. Hmm I could build a box on the front that the battery slides into. I will investigate and maybe change my mind. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 15, 2020 Share Posted December 15, 2020 I did not need to do any real modifications when I convertedmy Ballerina Quote Link to comment Share on other sites More sharing options...
Nigel R Posted December 15, 2020 Share Posted December 15, 2020 "I like the idea of moving F1 forward because of the extra flexibility with battery positioning." The other - similar - option, would be to build out a motor box on the existing F1. This would mean you can keep the fuselage parts you have, without modifying them. I have done this on a model where I needed to slide the lipo forward a bit. Cut out a nice square hole in the firewall. The motor box is just liteply in this size. It needs to sit "inside" the hole in F1. Four rectangular pieces of liteply for the sides, and a normal ply front piece which sits inside the box sides. Excuse my five-year-old-boy style artwork! Note, the box does not need to go back behind the firewall, although it may be handy to use the bottom surface as a lipo tray. Picture shows (badly) the top view. Edited By Nigel R on 15/12/2020 10:35:44 Quote Link to comment Share on other sites More sharing options...
kc Posted December 15, 2020 Share Posted December 15, 2020 Extending the fuselage makes it easier to fit the Lipo into the plane and room for the ESC. Building a box at front seems like more work - needs accurate cutting to ensure no thrust changes, plus cutting a hole in F1. Needs to be firmly glued to fuselage to ensure motor does not pull itself off. Whatever is simplest is usually best. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 15, 2020 Author Share Posted December 15, 2020 The difficult bit for me is working out what is the simplest. I usually spend more time working it out when it would have been quicker just going with the hard way. Peter, Yes no need to modify the Ballerina just add a bit of lead. Woolly thinking on my part which comes with age, well it has for me! I have been going through the scrap box and cutting up ply for the extension. More to come. Cheers Steve Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 16, 2020 Author Share Posted December 16, 2020 Extensions done. Guide rails added. and glued. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted December 16, 2020 Share Posted December 16, 2020 Looks good Steve, more than one way of skinning a cat (apologies to cat lovers). Quote Link to comment Share on other sites More sharing options...
kc Posted December 17, 2020 Share Posted December 17, 2020 It looks fine. How much did you extend F1 in the end? I notice that you followed the plan and put the u/c blocks behind F2. I wonder why it was designed that way - bet theres a good reason. Perhaps to get more room for the tank in the i/c model. If the blocks were in front of F2 the u/c wire could be straight and still have the wheels in the same place. As designed you have to remember the piano wire has to be 'handed' and cannot be interchanged. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 17, 2020 Share Posted December 17, 2020 I probably had a very good reason for designing the U/C mounts that way but it was over 10 years ago and my memory doesn't last that long. In fact there are some models that I designed and published since then of which I have no memory at all. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 17, 2020 Author Share Posted December 17, 2020 KC 1 1/4" as you said 32mm in my money. That looks fine to me but time will tell. Pictures to follow. Cheers Steve Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 17, 2020 Author Share Posted December 17, 2020 Here is the proof, not that it's needed. plenty of room for batteries. even 4000 4S Plenty of options, which is what I like. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 17, 2020 Share Posted December 17, 2020 JUst a very small point that few people (Often including myself) do. Where you have a thick doubler it is a good idea to champher the edges down to nothing. If you don't do that it generates a stress point and THAT is were it will break in a crash. The tapered off sheet allows a little bit of flex at the joint which spreads the loads. You NEVER see a sharp change of section on a straight line on full size aircraft structures. It isn't nearly so important where a 1/32 ply doubler ends because there is some flex at that point unless it ends right on a former which would be very bad design. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 18, 2020 Author Share Posted December 18, 2020 That makes sense Peter and from now on that is what I will do, too late to change on this build. Formers added. Built over a straight line which was not that easy to do, I will have to invest in a SLEC jig! Battery plate made from lite ply and support frame work added to the fuselage. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 18, 2020 Share Posted December 18, 2020 Looks very smart Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 18, 2020 Author Share Posted December 18, 2020 Thanks Peter Does this look like KC's drawing? I tried my best to copy it. Battery tray glued in from the bottom showing the framework. and from the top. Now I have to decide how to build the top hatch and fix it. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted December 18, 2020 Share Posted December 18, 2020 I tend to use nylon hinges bolted to the hatch and rear former At the front I always use one of those nylon spring loaded bolts. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted December 19, 2020 Author Share Posted December 19, 2020 Hinges as it happens I want to try covering film hinges and magnets. My thoughts now are to use lite ply hinged at the front with magnets to hold it in place. If I cut the ply to the width of the fuselage and to the length from F1 to F2 then cut out the centre to leave a frame which will be glued in place and the centre will be the hinged hatch. I will give it a go. Nothing ventured nothing gained. This designing lark is fun! I love Skylarks. Cheers Steve Quote Link to comment Share on other sites More sharing options...
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