reg shaw Posted January 2, 2014 Share Posted January 2, 2014 Hi folks, my first thread on here and my New Years resolution (one of them anyhoo) is to persevere, ie. learn to use this forum more! So, here is the current build. Its not going to be quick as I'm only building it at school in my lunchtimes and an hour in the evenings. The build is to half scale, 3m span but only about 1.5m long! Its being built exactly as the full size, using sketches and dimensions found in its designer Henri Mignet's 1936 book. The only difference in my model to the book is the front end as the particular Flea I'm copying is powered by a Ford 4 cylinder side valve motor car engine, so the front end is a bit different to the standard Flea. G-AEFK was sponsored by Bassetts and was decorated with Licquorice Allsorts all over its fuselage, plus a very rare rendition of Bertie himself on the rudder. Rumour has it that it was painted by William Heath Robinson but this has yet to be confirmed, he did paint another aeroplane within a year of this one so it remains a possibility. First off, hopefully a pic of the book and the Bassetts Flea I'm hoping to copy. Edited By reg shaw on 02/01/2014 22:28:11 Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 2, 2014 Author Share Posted January 2, 2014 Ah, not quite as planned! Try this perhaps? Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 2, 2014 Share Posted January 2, 2014 I thought the Bertie Basset bit was a legpull! Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 2, 2014 Author Share Posted January 2, 2014 Since there were never any plans published, just the book and a short series in Practical Mechanics magazine that both showed dimensioned sketches, the first job is to draw out straight onto my 1/2 scale plywood, the forward fuselage sides. Since my front end is different, I drew out the original shape and then taking angles from the few pics I have of 'Bertie' the known angles and lengths were used to draw out the new shape. This was the oversized to give some adjustment allowance when the front end is pulled together. From this basic start, the rest of the fuselage is attached, freehand stylee. Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted January 2, 2014 Share Posted January 2, 2014 Welcome aboard Ian! I'm sure that many will follow your adventures here. tim Quote Link to comment Share on other sites More sharing options...
Glenn Stratton Posted January 2, 2014 Share Posted January 2, 2014 Unique 1/2 scale topic, look forward to watching your progress Ian, I might have missed it, but out of curiosity what are you going to power Bertie with? Edited By Glenn Stratton on 02/01/2014 22:59:27 Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted January 2, 2014 Share Posted January 2, 2014 Ian, Looking forward to this, what power plant have you got lined up? Rich Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted January 2, 2014 Share Posted January 2, 2014 they have a couple at newark air museum i believe. Mignet HM.14 Flying Flea BAPC.43 National Benchmark Mignet HM.14 Flying Flea (cockpit) BAPC 101 Significant Edited By Tony Bennett on 02/01/2014 23:03:43 Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 2, 2014 Author Share Posted January 2, 2014 Not quite unique Glenn, a good mate is further on with another! His is Zenoah 62 powered. I was aiming for a geared Zenoah 38, but ground clearance would have been a minus value, so I had a re think and am going Zenoah 62 too. The plan is to have the Zenoah inverted, cooled through the 'car radiator' and making the exhaust Ford sidevalve shaped so the muck comes out of the right places. That's the plan anyway! Here's a pic of the Carden Ford conversion used in aeroplanes, most famously the Chilton DW1 at Old Warden. Ian. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted January 2, 2014 Share Posted January 2, 2014 Hi Ian. Great to see you here. I have this bookmarked, it's going to be interesting Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 2, 2014 Author Share Posted January 2, 2014 Thanks folks, thanks for the re welcome!! Next job was to join the fuselage sides together, again using formers described in the book, gusseted, lathed and doubled where the great man says. A former in front of the axle box, the dashboard panel and the seat back. Before this though, the internal side doublers, bearing blocks for the wing crank, rudder pulleys and the steel straps and ash block reinforcements at the axle hole area had to be sorted, using scale thickness steel and bolts etc. Then it was the sides that went together. The book is great in that it leaves very little out, all blocks and holes for flying wire brackets and even the seat belt bracket holes are mention to save you missing them out! The front end ahead of the axle is left with no structure in it for now until the standard Flea fuselage is constructed behind, so things can be rethunk if necessary. Ian. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted January 2, 2014 Share Posted January 2, 2014 Hi Ian , I will be watching this one with great interest , as i also like Flying fleas and have built a few in the past . I can not seem to find the video i once seen of you flying a small one that flew into the camera after the camera guy asked for a close up . it was called angry bee if memory serves me right . Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted January 3, 2014 Share Posted January 3, 2014 I also have many photo of the full size one at Lakeland motor museum . Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 3, 2014 Share Posted January 3, 2014 We are in for a real treat, thanks for posting the Bertie build I can't wait to se what you get up to with this one Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted January 3, 2014 Share Posted January 3, 2014 Welcome Ian, good to see you and look forward to seeing progress Quote Link to comment Share on other sites More sharing options...
Kevin Fairgrieve Posted January 3, 2014 Share Posted January 3, 2014 Nice to see you here Ian. More for the masses. Kev Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 3, 2014 Author Share Posted January 3, 2014 Posted by Stephen Jones on 02/01/2014 23:57:46: Hi Ian , I will be watching this one with great interest , as i also like Flying fleas and have built a few in the past . I can not seem to find the video i once seen of you flying a small one that flew into the camera after the camera guy asked for a close up . it was called angry bee if memory serves me right . Hi Stephen, that vid is called 'Killer Flea', Not a good place for a lack of battery!! Dave, the videographer has already warned that we may not get away with it using this one! Here hopefully, is said video. Ian. http://youtu.be/cz4bvFegI6M http://www.youtube.com/watch?v=cz4bvFegI6M Edited By reg shaw on 03/01/2014 08:28:06 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted January 3, 2014 Share Posted January 3, 2014 This is a great choice of a fascinating subject, there's a temptation to have a crack at building a real one in the back garden. At that scale it's going to replicate the aerodynamics of the original, I imagine. What about consideration for the early problems with fatal nose diving tendencies? I think I read somewhere the this problem, which lead to the banning of the Flying Flea in the UK, was found to be caused by overlap between the trailing edge of the front wing and the leading edge of the rear. This was described as causing a "slot" effect which increased the lift of the rear wing to a point that couldn't be overcome by the front, leading to an irrecoverable dive if the nose was dropped beyond a certain angle. The modification was to move the wing positions to create a clear gap between the two and it was considered that this made the Flea safe. I don't know it this is absolutely accurate but I'm sure it's what I heard. Do your drawings show that Reg? Quote Link to comment Share on other sites More sharing options...
Martyn K Posted January 3, 2014 Share Posted January 3, 2014 This looks like another interesting one... following. Martyn Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 3, 2014 Author Share Posted January 3, 2014 The drawings in the book are for the unaltered Flea. You are absolutely correct in that the problem was a 'slot' effect on the rear wing. This was made worse by the methods of achieving the correct CofG. All one had was the position of the front wing to get the balance right. Using a very light motor meant that the wing had to go backwards, increasing the slot effect on the rear wing. Heavier motors were best, since the wing was further foward and the separation adequate. The heaviest motors used in Fleas were the car engined derivatives, usually Ford 8 and 10, Austin 7 and 8 etc since they are substantial lumps, unlike some of the motorcycle engines used. Thats said though, having the ability to 'pull' too much up elevator was also the issue, stalling the front wing while the back still flies. I've had a few Fea models over the years, the worst was a 1/4 scaler which did succomb to the Flea bunt quite spectacularly. The general rule is that the elevator is only really used for trimming, altitude is controlled by throttle, Mignet says the he's designed a car for the skies, being able to fly a conventional aeroplane is a disadvantage. Ian. Quote Link to comment Share on other sites More sharing options...
riverlandgirl. Posted January 3, 2014 Share Posted January 3, 2014 These fleas are a catching! I will be watching this with interest too! fellow flea fan Lynn Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 3, 2014 Author Share Posted January 3, 2014 The rear of the longerons are closed up with an ash stern post and steel brackets at the top and bottom. Once again, Bertie differs slightly from a conventional (!!!!) Flea in that it has a conventional rudder horn and hinge set up, doing away with the twin wheel contraption and using a normal skid. The cockpit floor can now be fitted, screwed in place and removeable to gain access to the joystick and rudder pulleys etc.The two halves of the fuselage sides are scarf chamfered together over a distance of 10mm (the width of the upright on the inside) The whole fuselage is now unbelievably rigid, even without the top and bottom of the rear end fitted. Ian. Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 3, 2014 Author Share Posted January 3, 2014 Axle next, using a thick walled steel tube of 20mm diameter. It has a couple of brackets to keep the axle inline in the fuselage, plus 4 retaining 'winged' washers made up, again, all as per the book in 1/2 scale materials. The wheels were obtained from Ebay, luckily the roller bearings were a good fit on the tube! Ian. Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted January 3, 2014 Share Posted January 3, 2014 wow is all i can say. Quote Link to comment Share on other sites More sharing options...
reg shaw Posted January 3, 2014 Author Share Posted January 3, 2014 Cheers Tony. Next up was the rudder, and a big one at that, it makes up a quarter of the models length!! Laminated spruce outline, cyparis spars and spruce rib strips. The outline was steamed over a boiling kettle at the top front corner as its too tight to do without. Blocked in where the hinges and horn are to be, then the spar was capped with .5mm ply along with the semi circular gussets at each junction. Ian. Edited By reg shaw on 03/01/2014 21:24:28 Quote Link to comment Share on other sites More sharing options...
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