Electriflier Posted August 22, 2015 Share Posted August 22, 2015 It's me again!..... Been toying with the idea of building a nice twin-engine aircraft and suggestions such as the B25, the DC3 were considered but frankly, one aircraft kept coming to the top of the pile....... The 'Mossie' OK, I know that a Tony Nijhuis designed Mosquito plan is due to be released in one of the mag's in September but those of you who know me will know that I do like to make things difficult for myself and design my own. The TN free plan is a 72" version I believe, conventional balsa build and I know vac- formed parts will be available to accompany the build. At 84", this one might benefit from a canopy from Brian Taylor's design which is in or around this size. I have found a project on another forum where the forum member has obviously spent many hours designing and drawing a huge Mosquito in CAD and has made his drawings available to all. I have been studying these drawings now for close-on a week now to see if I could use any part of them as a starting point in my build. So, before I start posting photographs, I have sought his approval to use any part of his CAD work before I start uploading images of my design. Once again, this model, as with the last build (AT-6 Texan), the benefactor will be Mr Rawlinson who, quite clearly, has far more room in his hangar than I do. I have already spec'd the motors, ESC's and retracts to suit the model so am getting quite close to starting to cut some Depron. Anyone up for it? Roy Quote Link to comment Share on other sites More sharing options...
David Holland 2 Posted August 22, 2015 Share Posted August 22, 2015 I'm sitting at the computer, biscuits on the plate and coffee in a large mug! Take it away, Roy. David Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted August 22, 2015 Share Posted August 22, 2015 Ooooo now you really do have my attention Quote Link to comment Share on other sites More sharing options...
Martian Posted August 22, 2015 Share Posted August 22, 2015 love the mossie i shall be following Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted August 22, 2015 Share Posted August 22, 2015 Just hang on a few mins will you Roy, I need to get several packets of Ginger Nuts to follow this one...... Quote Link to comment Share on other sites More sharing options...
Philip Rawlinson Posted August 22, 2015 Share Posted August 22, 2015 Money boxes have been emptied, settee cushions rifled and feeling oh so lucky that I have another depron guru masterpiece to look forward to. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 22, 2015 Share Posted August 22, 2015 Brilliant. there were so many variants of the Mosquito that you have loads of scope.What about the Tsetse? A 57mm Depron cannon would be no obstacle for a chap of your talents. Quote Link to comment Share on other sites More sharing options...
Ian101 Posted August 22, 2015 Share Posted August 22, 2015 I'm up for it Roy. I need to be shown how to do it properly! Ian Quote Link to comment Share on other sites More sharing options...
Pilot_Chuckle Posted August 22, 2015 Share Posted August 22, 2015 excellent ! best start planting the depron trees Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 23, 2015 Share Posted August 23, 2015 Have pulled up a seat, this is gonna be good... What sort of powertrain are we looking at this time - a "double the Spitfire" 4S, or are you going for 6S this time? Will there be a sound system on board? And do you take commissions, I'd love a Spit just like yours! Quote Link to comment Share on other sites More sharing options...
Electriflier Posted August 23, 2015 Author Share Posted August 23, 2015 Gathering together bits and bobs that I'm going to need for the build. Eyes always open for something that can be used in a build, I came across the cheapest, nastiest type of broom handle that you can buy. You probably know which type I mean. The ones that are as light as a feather with a plastic screw thread on the broom end and are coated in a shrink-wrap type plastic coating....... yeah those are the ones! Strip the plastic off and underneath you'll find a chrome-looking tube about 21mm OD which is incredibly light. The aforementioned broom handle after plastic coating has been removed - light as a feather! This will be used in the outer wing sections as the stiffener/wing joiner. The tube fits perfectly into an old heli' tail boom tube and so, the tail boom tube will be the wing socket. The lightweight aluminium tail boom. Towards the TE of the outer wing sections, I will need another plug and socket arrangement to stop the wing swivelling around the wing tube. I will be using micro-bore white plastic central heating tube as the socket and 11mm hardwood dowel for the plug. I'll make it clearer once I start uploading sections of my drawings. As I mentioned, Brian Taylor's Mosquito is around this size and so today I ordered the canopy from Traplet publications. As for the proposed motors setup, I intend using 2 x Overlander T3548/05 Brushless motors. 900Kv running on 4S, 2 x 60A Esc's with an estimated joint power output of circa 1400W when swinging 13" 3 bladed props. I know that at 13", the props will appear a little small from a scale point of view but to use these motors, it's a price I'm willing t pay.The motors by the way weigh 170gms each so, they're a little smaller and lighter than the motors used in the Spit' (Matty). There will always be the opportunity to open the taps further by using up to 6S should we need but obviously, the prop size would then drop even smaller to around 11". Reading the comments above, I notice the usual crowd and it appears there's quite a lot of biscuits being consumed during these builds - *nb Mr Rawlinson! Great to have you all along and I look forward to reading your postings, comments, ideas, criticisms, suggestions as the build progresses. Right...... off for some biscuits! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 23, 2015 Share Posted August 23, 2015 A build like this justifies a bag of scratchings. It's worth more than a few hob-nobs. Quote Link to comment Share on other sites More sharing options...
Andrew Price 2 Posted August 23, 2015 Share Posted August 23, 2015 Scratchings Colin???? I consider myself fortunate that I discovered what they are made from - before I got to eat a single piece. What a lucky escape!! I'll settle for a (large) packet of bourbons. So. Yes, Roy. I am sitting comfortably. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted August 23, 2015 Share Posted August 23, 2015 Did you ever see anyone in 633 Sqd eating Scratchings? No.... Did anyone ever say "back home for scratchings and medals then boys"?, No..... I suggest there is a reason for that, they (scratchings) certainly wouldnt be allowed in any Army Officers Mess I ever lived in, whilst I know the RAF have significantly lowered standards and panache and style since they ceased to be an Army unit, but even so scratchings...... Nice scavenging on the woing boom front there Roy....... Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted August 23, 2015 Share Posted August 23, 2015 The Mosquito is one of my all time favourites, and I am very much looking forwards to your build. CS Quote Link to comment Share on other sites More sharing options...
Electriflier Posted August 24, 2015 Author Share Posted August 24, 2015 Scratchings, biscuits?.......leave it out chaps. Every time I log in, I get hungry! Thank you CS for your comments..... it's nice to see someone is taking things a little more serious Briefest of updates..... A quick picture of some of the drawings to date. The orange shaded sections of the wing I'll probably use pink/blue foam, hot-wire cut. By doing so, I'll achieve the desired strength (With wing tubes and carbon passing through) at this load-bearing section of the model. You may be able to work out that the battery boxes in each nacelle (3mm light-ply) will hang from the wing tube (the battery box sides are actually wing ribs No's 4.5) and the base of the box will act as the anchor point for the 120 sized eflite retract bearers. The front of the battery box will be of 6mm ply which will form the motor mounting bulkhead. Cooling of the motors/batteries and ESC's should be pretty efficient as the front of the nacelle will be opened sufficiently to allow good airflow in around the motors. I'll vent the circulating air out through a rear vent in the nacelles. Cheers Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 24, 2015 Share Posted August 24, 2015 Can't fault your logic Roy. Putting the batteries in the nacelles is the way to go, I should have done that with my 1/12 scale Welkin, even putting the Lipo right forward in the nose left me with a rearward c of g problem. Modifications are required. I don't see any provision for wash-out in the wing, that would worry me. Quote Link to comment Share on other sites More sharing options...
Electriflier Posted August 24, 2015 Author Share Posted August 24, 2015 Evening Colin, A few degrees of washout will be introduced from the outer edge of the nacelle. Ribs 5 -14 will have their centrelines adjusted before I cut them in half. I haven't explained yet that the wing outer sections will be ribs on top of and beneath a planform 6mm sheet as with the Hercules. How much washout did you build into the Welkin? Quote Link to comment Share on other sites More sharing options...
David Holland 2 Posted August 25, 2015 Share Posted August 25, 2015 Goodness, that's a packet of Maryland Cookies and three cups of coffee gone already😉. Roy, could you explain the reasoning for your motor choice, please? If 6s pack will fit could you have gone for lower kv motors swinging bigger props for a similar weight/current/watts/flight time result? Picking your brain a little further, will you skin the foam centre section with depron or go straight to glass? Might as well go to bed now as the biscuits have gone. Regards, David. Quote Link to comment Share on other sites More sharing options...
lightning 759 Posted August 25, 2015 Share Posted August 25, 2015 will be watching this one great choice andy Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted August 25, 2015 Share Posted August 25, 2015 Hi Roy. The first 58" Welkin that I gave to Dave Chinery had 2 degrees. He was worried that with the sharp taper and narrow tips that tip stalling would be a problem. When he flew it though he found that it wasn't and although it could be induced to drop a tip, there wasn't an issue. However, I built 3 degrees into the 70" version and I think that will be fine, but I have to sort out the c of g before I fly it and that will need some alterations. Dave wrote about that model in the old "Flying Sparks" feature in RCME. Perhaps the Mixmaster is a good comparison, because that is tapered to 50% of the root chord at the tip and although less extreme than the Mosquito, it is all in the leading edge sweep. I built in three degrees progressive from root to tip and the stall characteristics are totally benign, with no tip stall tendencies. I've never forgotten that the full size Spitfire has 2.5 degrees and Jeffrey Quill describes how it doesn't drop a wing, just progressively mushes down straight and won't drop a wing in the tightest of high g turns either, a real advantage against a 109, which would high speed stall, as a P51 can also do. For me, three degrees is a safe bet. I also have a feeling that progressive wash-out improves the wing because it will have a slight modifying effect on the tendency for the airflow to move out diagonally across the wing rather than straight back, a bit in the way that modern winglets do. That must reduce vortex effects at the tip to some degree and that reduces drag. It might be one of the reasons (along with the thin section)that the Spitfire had such a phenomenally high limiting Mach no, higher than the laminar flow wings that were designed later to replace it. So for me it is three degrees, it leaves you to decide what mean angle you want so that you can determine the the angle at the root. I've never looked to see if the full-size Mosquito had any wash-out, perhaps not. However, it was known to be a handful at times and with an engine out, the standard instruction was to bail out, don't try and land it. That tells you something. I certainly wouldn't go for less than two personally. Edited By Colin Leighfield on 25/08/2015 06:21:19 Quote Link to comment Share on other sites More sharing options...
Philip Rawlinson Posted August 27, 2015 Share Posted August 27, 2015 Roy, I am again getting giddy ! I will hopefully be calling at yours and Charles fine emporium tomorrow armed with a selection of the finest Belgian biscuits (if Aldi have them on special offer) and the first installment of loose change. The plans look awesome. I am so glad you chose to adopt me even at my age of 37. P.S. What were you doing out enjoying yourself today and wasting valuable building time Quote Link to comment Share on other sites More sharing options...
Electriflier Posted August 28, 2015 Author Share Posted August 28, 2015 Sorry for the lack of updates but I'm really finding that since I upgraded to Windows 10, adding photo's is proving difficult and the paste function doesn't seem to want to play. Working on it....... ooh it's let me add a photo...... drawing progress to date. Quote Link to comment Share on other sites More sharing options...
Electriflier Posted September 1, 2015 Author Share Posted September 1, 2015 Good Evening, Getting quite close now to completing my drawings. I have taken them to the printers today to get a copy run off so that I can take a closer look at full size. I ordered the canopy parts from Traplet and they duly arrived 5 days later. I have to admit to being pleasantly surprised in that it's not just the canopy that you're purchasing, it's the full 5 pieces that you will require if building the Perspex-nosed bomber with the additional side glazing and extra cockpit bubble. Undecided yet as to which variant Phil prefers but we can address this a little further down the road. Shown in the photo is a small section of the pdf printout that I've taken to be printed today. It's around 3 metres x 1.3m in size and I've not wasted much space. As soon as I get them back, I'll be cutting all my ply parts first before setting-to with the Depron. Keeping the post short for the time being as already explained, I'm struggling a little with inserting images into my posts at the moment. Regards....... Roy Edited By Electriflier on 01/09/2015 21:09:16 Quote Link to comment Share on other sites More sharing options...
Monz Posted September 1, 2015 Share Posted September 1, 2015 Roy, do yourself a favour and revert to your previous version of Windows. Best thing I did and I only had 10 for about 30 mins! Mozzie is looking good so far. Quote Link to comment Share on other sites More sharing options...
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