Martyn K Posted November 19, 2012 Author Share Posted November 19, 2012 I changed my mind on the removable tank. There were too many compromises.. Here is the refitted tank and surrounding structure using 1/4" triangle and 3mm liteply. Note the balsa wedges securing the engine mount to the tank floor and cockpit floor. Hopefully it will be strong enough, but there isn't much space for any other solution.. Looking down from underneath (if that makes sense..) with the engine in place and the fuselage sides clamped up while the glue dries.. I also followed the 'Lowe' advice on fitting a tank (Dec 2012 RCM&E) and sealed the entry to the tank through the bulkhead with bath sealant.. The tailpost is a short offcut of 1/4" sheet,aligned so that it is vertical (no twists) and straight (the black alignment line down the centre of the board). The 1/2" soft balsa cheeks (under the tank) added and planed to size.. The hardwood block in front of the firewall is to support the lower pivot for the steerable noseleg. Which brought me on to adding the tailplane.. which was a bit tricky. This needs to be done now because the upper fuselage decking overlaps the tailplane. The alignment steps were. 1. Get the fuselage sides vertical 2. Dry fit the tailplane and sand the seat for a good fit and that each tip is the same height off the board 3. Check the distance from each tailplane LE at the joint with the tip block to a reference point at the centre of F3. They should be equal(mine were) Quite an iterative process to get all 3 correct. Note the wedges under each tailplane tip holding everything in alignment while the glue dries. The upper triangle section is actually carved/planed/sanded from some very nice 1/2" sheet balsa. Use triangle if you wish if you can get a nice stiff light piece. I didn't even bother looking... I left it tonight with the upper deck glued down. Photos next time. More to come Best wishes Martyn Edited By Martyn K on 19/11/2012 22:07:02 Edited By Martyn K on 19/11/2012 22:09:58 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted November 19, 2012 Share Posted November 19, 2012 Ooooh!! Lets hope that tank doesn't leak....... Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 19, 2012 Author Share Posted November 19, 2012 Hi Steve A risk I will have to take... especially worrying because last weekend the tank on my AstroHog started leaking badly.. If it leaks, I'll have to resort to surgery, but where would I start cutting...? Martyn Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted November 19, 2012 Share Posted November 19, 2012 Hopefully a risk worth taking Martin......I can't remember the last time I had a leaky tank.....but then I can get at them all...... I just know that the aeromodelling Gods will decree the first time I build in a tank it will leak.... ....Or the feed pipe will come off..... .....or develop a hole in the feedpipe....... I think it might be wise to burn some nitromethane incense or sacrifice a couple of virgin......sheets of balsa to pacify the Gods if you go down this route.... Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 19, 2012 Author Share Posted November 19, 2012 I have pressure tested the tank for leaks, now need to be philosophical, I would rather have a leaky tank than the engine and mount becoming detatched mid flight.. It's a question of compromises. I knew there wasn't going to be that much space.. Lots of virgin sheets sacrificed in this model so far... and many more to come. From experience though, It doesn't seem to stop em crashing.. Martyn Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted November 19, 2012 Share Posted November 19, 2012 That is very very tight! I can't see the plane in my eyes, but from looking at the pictures I would consider a slightly smaller tank. I did that with the Funfly and it made life easier in that. But I am sure it will be fine, and the plane looks great! Keep up the good work, I like these downsized versions of classics for 25 engines! CS Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 19, 2012 Author Share Posted November 19, 2012 Hi CS It's a 6oz tank. That should give me 10-12 minutes flying time with a 25. I don't think going smaller would actually give me that much more space and then it's another compromise.... If it breaks it breaks, I'll just rebuild it.. (I do a lot of that) I am now thinking of the next 25 sized miniature classic after this. Maybe a Superstar.. Any thoughts/preferences anyone? It will be next years project, got too many on the go at the moment Martyn Edited By Martyn K on 19/11/2012 22:38:30 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 20, 2012 Share Posted November 20, 2012 Dirty Birdy? If you think the Curare is slim, then a DB25 should really make you work to fit everything. in. Or how about an MFA Chevron? One good thing with the Slec tank is that if you need to replace the clunk tube as long as the feed pipe is lined up with a hole in the centre of the engine mount rear face then the clunk can be removed with a long tube spanner fed in through the nose ring and engine mount. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 20, 2012 Author Share Posted November 20, 2012 Thanks Bob, I'll take a look - it's a design I am not that familiar with.. Martyn Edited By Martyn K on 20/11/2012 13:52:36 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 20, 2012 Share Posted November 20, 2012 Dirty Birdy Courtesey of the RCMF forum I'm afraid: Chevron lots more ideas on the Trenton site under classic image base - Chevron is near the bottom. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 20, 2012 Author Share Posted November 20, 2012 The Dirty Birdy looks very nice - better with an inverted or sidewinder engine though. Not sure of the chevron - too jetish for my taste. -- Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 20, 2012 Author Share Posted November 20, 2012 Found a 48" span version of a Dirty-Birdy - looks a little large for a 19 - would be perfect for a 25 Tweedy-Bird Martyn edited coz link was wrong... Edited By Martyn K on 20/11/2012 17:45:19 Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 20, 2012 Share Posted November 20, 2012 .15-.30? a 15 in a 4 foot plane? Now that really would have to be a light build. Quote Link to comment Share on other sites More sharing options...
Chris Poulton Posted November 20, 2012 Share Posted November 20, 2012 Martyn hi, are you going to manage to get the curare to a kit cutter? i would buy a short kit instantly. as for a follow up, it would have to be one of two in my books.....a super star as you mentioned, or a komet , same era but an italian design. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 20, 2012 Author Share Posted November 20, 2012 Hi Chris Hopefully - yes.It's just been a bit slow with some (paid) work commitments. Hoping to get back on with the CAD work for ribs for the wing very shortly. I think that I am going for a symmetrical section as I originally envisaged. That way I shouldn't have to worry about thrust line and incidence changes etc. Also considering a Kraft Slik fly for a 25. as one of the options.. gone off the Dirty Birdy as its already been done.... Martyn Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 20, 2012 Author Share Posted November 20, 2012 Started work on the DXF layout for the laser cut wing ribs tonight. There will be 4 sheets of 36x4" required. I am hoping to get the tail ribs onto a single sheet. Regards Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 21, 2012 Author Share Posted November 21, 2012 Amazingly,I have finished the DXF files for the wing and tail ribs tonight. I learnt a couple of new techiques for trimming lines. They are here in a zip file for download They are 'raw' layouts, no allowance has been made for u/c mounts doublers, wedges dihederal braces etc. (Standard spar slots have been included i the layout). I hope that is OK. I prefer to cut these when I am doing the assembly, it allows me to make any necessary adjustments due to material variations. I would be grateful if someone would kindly sanitise them for me. They are in DXF format - there are various viewers available if you don't have anything suitable. They should fit on 2 sheets of 36x4. 2 sets will be required per model Regards Martyn Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 22, 2012 Share Posted November 22, 2012 A quick look leaves me with just one question - why the big 'oles in w1-4 just where I'd be expecting to see the u/c mounting rails located (50%ish chord)? Am I missing the big picture here? If it's for servo leads, I think I'd run them in front of the spar to leave the rear half of the ribs solid above the u/c mounts. ps - Visio will display the dfx files. Edited By Bob Cotsford on 22/11/2012 12:25:28 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 22, 2012 Author Share Posted November 22, 2012 Hi Bob That was the plan... I didn't place then in the LE section because that will be totally boxed in. What I can do is remove them and leave where to locate the servo leads up to the builder. Would that suffice? Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 22, 2012 Author Share Posted November 22, 2012 PS - thans for the tip about Visio as a DXF viewer, I hadn't realised that. Martyn Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 22, 2012 Share Posted November 22, 2012 are you planning on a hand launch version then Martyn? "leave where to locate the servo leads up to the builder." sounds like a plan does that. It will allow for fixed u/c, retracts, taildragger (blasphemy!) or no wheels and whatever servo installation the builder fancies. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 22, 2012 Author Share Posted November 22, 2012 Definitely not. ... my main U/C blocks (not retracts) will be glued and screwed to the main spar ply brace (I think). If you are OK with it so far, I'll get some pricing. Martyn Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted November 22, 2012 Share Posted November 22, 2012 Just in time for Christmas! Are you thinking of supplying part kits, or just getting a source and price then leaving it to prospective builders to order for themselves? If the former you might like to think about getting deposits in before placing any orders, you wouldn't be the first to get their fingers burnt ordering on promises! Edited By Bob Cotsford on 22/11/2012 14:50:01 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted November 22, 2012 Author Share Posted November 22, 2012 I'll see what the pricing looks like first. I haven't done any ply parts yet, I have only just completed the wing parts. I am not sure I want to supply kits, but I would be interested to know if there is enough interest as I may be able to persuade my LMS to take it on. But.. for this first one, (there may be more), I will talk to the cutter and get a master set cut and check they are OK. If it looks and feels OK and peeps are happy with the limitations(ie they will have to cut their own U/C blocks and trim for the doublers and braces) etc then I'll publish the details on getting their own set. Is that OK? If anyone would like a set would you mind replying to this thread so I can prime the cutter what the demand is likely to be. Not high I would imagine... Thanks all Martyn Edited By Martyn K on 22/11/2012 14:56:53 Quote Link to comment Share on other sites More sharing options...
Chris Poulton Posted November 22, 2012 Share Posted November 22, 2012 i am DEFINITELY in Martyn. Quote Link to comment Share on other sites More sharing options...
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