Marty_d Posted January 13, 2016 Share Posted January 13, 2016 That'd be a target for every trolley in the supermarket car park. Link to comment Share on other sites More sharing options...
planet47 Posted January 14, 2016 Author Share Posted January 14, 2016 Looks okay to me pylon500 but may be you could do an image of the finished product in gold? Link to comment Share on other sites More sharing options...
bexrbetter Posted January 14, 2016 Share Posted January 14, 2016 Thanks for the updates P47, appreciated. 1 Link to comment Share on other sites More sharing options...
pylon500 Posted January 14, 2016 Share Posted January 14, 2016 Best I can do in a hurry... Takes a while to get back into using photoshop, and I was never a pro in the first place. 3 Link to comment Share on other sites More sharing options...
planet47 Posted February 5, 2016 Author Share Posted February 5, 2016 Link to comment Share on other sites More sharing options...
planet47 Posted June 2, 2016 Author Share Posted June 2, 2016 3 1 Link to comment Share on other sites More sharing options...
bexrbetter Posted June 2, 2016 Share Posted June 2, 2016 Well done! 2 Link to comment Share on other sites More sharing options...
planet47 Posted July 30, 2016 Author Share Posted July 30, 2016 One day soon (I suppose) I will probably have to part with my beloved quicksilver. It was never just a plane - it was also the first thing I ever owned without having to get a loan and the first time and only time I have towed a trailer by myself over a good portion of Australia to bring it back here (thousands of kms at 60-70km/hour over 5 days). It feels like preparing myself to lose a limb! 1 Link to comment Share on other sites More sharing options...
bexrbetter Posted July 30, 2016 Share Posted July 30, 2016 It feels like preparing myself to lose a limb! 1 Link to comment Share on other sites More sharing options...
rotax618 Posted July 30, 2016 Share Posted July 30, 2016 The concept looks good but I can see two problems, unless you have something very heavy to put in the nose or you are planning on sweeping the wings, I suspect that the pilot and pass are not going to bring the CG forward enough for stability. The second problem is getting smooth air to flow around the rear of the pylon into the prop. I have had some experience with this problem when I designed and developed the Boorabee, which is a tandem and therefore less of a problem, I finally solved the problem with vortex generators. Vortex generators can delay the separation of the boundary layer by re-energising it, wings equipped with VGs still stall but at a greater Angle of attack, typically 15-18deg, from the looks of your design the rear of your fuselage is 30-45deg taper. You will probably be better off tapering the pylon 15deg and chopping it off square before the prop ( Kamm tail) Please accept my criticism as an attempt to help. There a far too few people willing and brave enough to design and build their own creation. Link to comment Share on other sites More sharing options...
pylon500 Posted July 31, 2016 Share Posted July 31, 2016 All these things have been worked on, no promise that I've solved all of them yet, but basically as you've said. Aircraft originally designed around a 912s, but there is an EA81 Subaru sitting there at the moment, so the wings may yet get swept. I am looking at an extension shaft for the Subi reduction system, ie, an extension between the block and the reduction system. Am toying with the idea of tall skinny radiator as the trailing edge of the pylon. Will never be able to get rid of the 'pusher' sound, but working on it. Link to comment Share on other sites More sharing options...
rotax618 Posted August 1, 2016 Share Posted August 1, 2016 Pushers are always noiser than tractor aircraft, particularly for the persons in front of the prop, pilot-passengers. I think that the noise of the engine and particularly the exhaust is being reflected from the propellor disk forward. I was going to test this by extending the exhaust outlet down and along the boom to exit behind the prop. Unfortunately all of the pushers I built had 2 stroke engines which dont perform well if you modify the exhaust. Another problem I encountered was a pulsing and vibration when I used a 2 bladed prop, this was caused by the prop blades passing through the wing wake in unison, three blades fixed this although 2 blades gave a better cruise. 1 Link to comment Share on other sites More sharing options...
planet47 Posted August 18, 2016 Author Share Posted August 18, 2016 This girl has got thus far 1 Link to comment Share on other sites More sharing options...
planet47 Posted September 9, 2016 Author Share Posted September 9, 2016 It used to look like a boat now it looks like a ship wreck 3 Link to comment Share on other sites More sharing options...
planet47 Posted September 12, 2016 Author Share Posted September 12, 2016 The shipwreck has become a boat again yay Link to comment Share on other sites More sharing options...
planet47 Posted October 14, 2016 Author Share Posted October 14, 2016 I'm told the other day that soon I will have to look at wing strut material - any suggestions? Link to comment Share on other sites More sharing options...
planet47 Posted October 14, 2016 Author Share Posted October 14, 2016 Whoops - I asked a question Link to comment Share on other sites More sharing options...
rotax618 Posted October 14, 2016 Share Posted October 14, 2016 Lightwing (Hughes Aviation at Ballina) still have strut material, the same as used on their Lightwing, not sure that they have the smaller size but I bought some of the larger section last year. The larger section has about a 32mm internal minor axis. 1 Link to comment Share on other sites More sharing options...
facthunter Posted October 15, 2016 Share Posted October 15, 2016 Yes streamline section aluminium, either extruded or formed from sheet folded and riveted at the trailing edge. Could be around a tube. Nev 1 Link to comment Share on other sites More sharing options...
Marty_d Posted October 15, 2016 Share Posted October 15, 2016 Yes streamline section aluminium, either extruded or formed from sheet folded and riveted at the trailing edge. Could be around a tube. Nev Nev, I've been considering streamlining the 701 struts (when I make them). Plan calls for round chrome moly which I've already bought, and I generally try to stick to the plan, but I also know there's a hell of a lot less drag if streamlined. If I do fold a sleeve and rivet at the TE, what's the best method to fix to the tube? Does it only require a couple of rivets top and bottom, or should there be a full length row - if so, does that weaken the strut at all? Link to comment Share on other sites More sharing options...
rotax618 Posted October 15, 2016 Share Posted October 15, 2016 Rivets do weaken the tube, the best solution is to only rivet the fairing at the ends of the strut and use a high strength double sided tape where the fairing touches the strut tube top and bottom. 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted October 15, 2016 Share Posted October 15, 2016 Having a rivet line at the Trailing edge is not much of a reduction in the section and the number doesn't affect the principle as it does in a stressed lap joint where the total number is significant in reducing cross sectional area. If you have a chrome molly tube why not use something like balsa or foam with a coating held on by straps. It's not load carrying, just streamlining. Nev Link to comment Share on other sites More sharing options...
Marty_d Posted October 15, 2016 Share Posted October 15, 2016 Having a rivet line at the Trailing edge is not much of a reduction in the section and the number doesn't affect the principle as it does in a stressed lap joint where the total number is significant in reducing cross sectional area. If you have a chrome molly tube why not use something like balsa or foam with a coating held on by straps. It's not load carrying, just streamlining. Nev I thought of lapping the fairing at the TE so the body of the rivets are inside the fairing - like this: Surely that would be a substantial drag reduction? Link to comment Share on other sites More sharing options...
facthunter Posted October 16, 2016 Share Posted October 16, 2016 It will be a substantial drag reduction with a section like that. More so if the rest of the plane has a bit of a clean up, and you are cruising above say 60 knots. Don't put rivets into your main structural tube as it will weaken it and create failure points. Nev 1 Link to comment Share on other sites More sharing options...
Bruce Tuncks Posted October 16, 2016 Share Posted October 16, 2016 I agree. A round section is terrible for drag. I have been told that a 1/4 inch diameter rod has the same drag as a Libelle wing. If you make the section too blunt, the airflow will separate before the trailing edge. I used to see this on my early SK Jab with the round trailing-edge struts. You could see the separation point when a little light rain left a line of dust, and those struts left a separation wake of about 15mm. Link to comment Share on other sites More sharing options...
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