kc Posted June 19, 2019 Share Posted June 19, 2019 Dean, I think most experienced aeromodellers would consider that reinforcing the engine bulkhead to fuselage with triangular fillet is absolutely essential. It is a feature of most designs.including this one. The consequences of an engine pulling out and hitting someone is too awful to contemplate. There is really no reason to leave the fillet off - it can be made from scrap balsa and does not need to be triangular or neat - and weight is usually added to the front of most models so no need to save weight. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted June 19, 2019 Author Share Posted June 19, 2019 THere is a big hole in the front cockpit floor which allows the hot air out Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted June 19, 2019 Share Posted June 19, 2019 I think that you are worrying about nothing. There are huge holes where the pilots sit. No need for anything else. Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted June 20, 2019 Share Posted June 20, 2019 Hi Martin, I dont intend on having holes where the pilots will be seated so this is why I asked the question...? Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted June 20, 2019 Share Posted June 20, 2019 You can just see the cooling air exit in front of Dick Dastardly's chest. It's where Peter says, in the front cockpit floor. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted June 20, 2019 Author Share Posted June 20, 2019 MIne is just where Trevor put his. You can hardly notice it. It has the advantage that it is cose the the rear of the battery. The air flows in under the motor, over the speed controller where it is most needed and then past the battery and straight out. IT WORKS Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 20, 2019 Share Posted June 20, 2019 "there is plenty of strength provided by the epoxy joint so no need to add any stock" Out of all of the joints in an airframe, the motor bulkhead to fuselage side is the one I would least want to reduce the strength of. Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted June 20, 2019 Share Posted June 20, 2019 Thanks Peter and Trevor, As I will be placing just one pilot into the rear seat I will make the hole in the front seat same as per Trevors pic. I will also place the re-enforcing for the motor bulkhead. Cheers, Dean Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted July 22, 2019 Share Posted July 22, 2019 Hi Dean - how is the progress of your Ohmen build going? Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted July 22, 2019 Share Posted July 22, 2019 Hi Chris, I have completed the cowl but slowing down now as I try to work out a good colour scheme. Also since I will be covering the fuselage with metallic I was thinking of covering the cowl also but I think it will be easier just to paint and would welcome any feedback on this..? Here are some pics of the cowl and the plane as it is more or less ready for covering. cheers Dean Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted July 22, 2019 Share Posted July 22, 2019 As you can see from my pics I covered the fus. with metallic and painted the cowl over tissue and dope, by far the easiest way to do it. By the way, that looks like a very neat job. Edited By Martin McIntosh on 22/07/2019 17:20:35 Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted July 31, 2019 Share Posted July 31, 2019 Hi Dean - yes it is looking very neat job. You are a lot further along than I am with my build although seeing how others are doing really helps to keep the motivation up. I have not thought about the cowl yet - to be honest I'm not really looking forward to it as i have not made a made up cowl before and the cowl ring is being cut by hand so will not be particularly even either - hopefully it will all come together in the end! I think the cowl screw cut outs make the covering a little intricate so perhaps painting i the best way to go. Looking forward to seeing how you get on. Chris Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted July 31, 2019 Share Posted July 31, 2019 Dean - a little off topic but how do you find your laser cutter - is it something you would recommend and if so what type / model do you have? Chris Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted July 31, 2019 Share Posted July 31, 2019 Hi Chris, The laser cutter I have is the Chinese made K40 which I purchased from ebay for around AU$550. As I prefer to keep things more simple the model I chose is with the analog dial not the digital version. You will need to invest in making some additions like adding an air compressor, hose and jet as well I would recommend to add LED lighting and replace the cutting table with a sheet of perforated steel with magnets to clamp your pieces, all up extra AU$150. I can send you some pics of the mods which I made if you are interested just let me know. With these mods I find it to be a very good laser cutter and engraver. I never use it at maximum power normally I cut at about 30-50% maximum. At 50% for example soft balsa up to 3mm is a single pass while 3mm plywood requires a second pass. I get the plan scanned at my local Office supply shop then I use Solidworks to trace allowing about 0.1mm for the cut. After tracing I copy and paste, laying out the traces into Inkscape with custom dimensions set for the width and length of the balsa wood I will be using for cutting. Inkscape allows you to change the colours of the traces which the K40 laser cutter automatically interprets Red for cutting and Blue for engraving. I could share the Ohmen files here if anyone is interested in doing it themselves just let me know. All in all if you plan on building a few models then you will find it a good investment. I have set up the laser cutter in my garage so should I need to re-cut any parts its super quick and great for all those plywood bulkheads. There is also a lot of video and user tips on the net. Dean Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted August 1, 2019 Share Posted August 1, 2019 Thanks for the feedback - I will have look and see if I can see it. And then I need to learn solidworks or turbocad and inkscape! This hobby never ends! Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted August 1, 2019 Share Posted August 1, 2019 Chris, if the cowl screw cut-outs bother you, there's a simple solution - don't have them. The cowl on my Ohmen is located using a couple of small dowel pegs, and retained by the film covering. Electric motors don't need maintenance, but if you need access you can run a scalpel around the join to remove and re-apply covering to replace. I used this method on my electrified Ballerina a few years ago, and it hasn't been off since. Quote Link to comment Share on other sites More sharing options...
Chris North 3 Posted August 2, 2019 Share Posted August 2, 2019 Hi Trevor - that is a neat trick. I will have a think about that one. Today I attached the bottom keeper rails to the hatch cover. Simply taped the hatch in position... ..turned the fuselage upside down, placed the rails hard against the fuselage sides and tacked with a drop of cyano.......then removed the hatch and ran a bead of superphatic glue along the inside edges of the rails. Job done and a nice tight fit. (Still haven't figured out how to rotate my photos in W10 as they are fine on the laptop but not once uploaded to the website) While this was drying I decided I had better finish the wings so that I can install the wing keeper plate. First thing is to shape the replacement aileron and so this was started with the razor plane- no pictures as it is the same as before and the building board is a complete mess!. Hopefully I can find some more time over the weekend. Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted August 2, 2019 Share Posted August 2, 2019 Hi Everyone, Thank you for all your positive comments on the plane. I was unable to purchase a hatch clip aka retainer and have been racking my head as to other options. I see one of the other builds used magnets but I would prefer a mechanical method so was just wondering what if any are the alternatives..? Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted August 2, 2019 Author Share Posted August 2, 2019 4-Max and SLEC do them.,AlsoEBay has them by the dozen Quote Link to comment Share on other sites More sharing options...
kc Posted August 2, 2019 Share Posted August 2, 2019 This is what i devised for the Ballerina and should work for any open cockpit design. Can be disguised as a control column etc. The brass bit is a servo ferrule with a washer and was tinned with solder before assembly. When assembled it is jammed in with a bit of wood and the soldering iron touched on, remove the wood when really cool. Edited By kc on 02/08/2019 13:47:15 Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted August 2, 2019 Share Posted August 2, 2019 Thanks KC Thats perfect.. I will make up one of these which will fit nicely into the cockpit. Many thanks again, Cheers, Dean Quote Link to comment Share on other sites More sharing options...
kc Posted August 2, 2019 Share Posted August 2, 2019 Dean, glad you like the idea. You will notice I also fitted another brass ferrule to stop the wire going too far forward - so my fingers can grab the bent part to operate easily. Of course the hatch had a dowel at the front to prevent hatch lifting off. The hardwood guide block stops the wire from dropping right out of the bulkhead when pulled too far back. Start saving all the old ballpoint pen springs......they are just right. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted August 2, 2019 Share Posted August 2, 2019 I have made these in the past but much simpler to buy a SLEC one. None too easy to position correctly which ever way you go. Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted August 7, 2019 Share Posted August 7, 2019 Hi KC, I assembled the hatch latch you kindly provided and it worked a treat. Here is a picture of the latch below. Its very easy to simply pull the wire and the hatch is free to lift out. Also I like the fact that there is nothing protruding above the hatch. Thanks Again Quote Link to comment Share on other sites More sharing options...
Dean Sarelius Posted August 7, 2019 Share Posted August 7, 2019 Hi everyone, Just want to know if I should be making some cut outs on the wing for the servo leads..? Quote Link to comment Share on other sites More sharing options...
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