Simon Chaddock Posted May 27, 2012 Share Posted May 27, 2012 The V/STOL in its various forms proved just too difficult to fly properly and ended its life in a 'terminal' crash, so here we go again! I have a currently unused 40" span high aspect ratio wing with compound 2 section flaps. The 2 motors from the crashed V/STOL are undamaged so its enough to be getting on with. As these motors are not particularly well matched (but the best of the four) it seems logical to use them in a tandem push/pull layout. A plan of the fuselage, pylon and motors with 5" props. They will be counter rotating. I make no apologies for sticking to a pod and boom pylon layout as it works well and protects the props. So far so good. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 28, 2012 Author Share Posted May 28, 2012 Starting to get an idea of what it will look like. The first smaller flap section is in place. I keep falling into the trap of making everything 'just big enough' and then regretting it when I actually come to fit everything in! Still flaps up it should be fairly efficient. Quote Link to comment Share on other sites More sharing options...
Stefan Hafner Posted May 28, 2012 Share Posted May 28, 2012 I was looking in on the first STOL tread every now and then, and what struck me was that the tailplane and rudder weren't in any of the propwash, which i would think at slow flight may have made things tricky. So i would think it'llbe better control on the mk2/3?? I also just thought, what about using an all moving tailplane in T tail configuration, would give a load of control at low speed and will certainly be getting plenty of airflow for the pod mounted engines. Will be interested to see how it goes. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 29, 2012 Author Share Posted May 29, 2012 A bit more skin on the pylon. Radio, servo and motors installed. The ESCs will be mounted in the pod between the motors. Not ideal, the ESC to battery leads will be on the long side but there is very little room elsewhere. It should weigh about the same as the previous VSTOL - 10oz all up. I suspect one of the problems with the earlier VSTOL actually was the airflow over the tail. With tractor props when the flaps go down even the prop wash over the top of the wing is significantly deflected downwards by the Coanda effect and adds to any nose up pitch caused by CofP changes from the flaps themselves. With a pusher the flaps do disturb the airflow into the prop (it makes a different noise) but the direction of the prop wash remains broadly the same. We shall see. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 31, 2012 Author Share Posted May 31, 2012 A bit more progress but still rather slow going. All the electrics installed and tested. The radio and ESCs are in the wing pylon. The 1000mAh 2s battery has to go right forward into the nose. The much heavier 2200mAh would be positioned under the hatch. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 31, 2012 Author Share Posted May 31, 2012 I am sure it will make not one 'halfpennyoth' of difference but I was interested in the principle - a "behind the prop" spinner! This slow fly prop has an extremely small hub and as the adapter puts the prop 10mm ahead of the motor bell it seemed logical to smooth the airflow a bit. A cowling extension up to the back of the bell completes the set up.. Oversize circles of Depron are simply glued to the motor face and then sanded to the required profile by running the motor. The prop adapter is still removable. As the motor is only drawing 50W I anticipate the exposed bell surface will provide sufficient cooling. The pusher motor at the other end will have more of a straight taper spinner. I suppose in doing things like this it is to be expected that progress will be bit slow! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 1, 2012 Author Share Posted June 1, 2012 Nearly there. Testing the flaps. I have just the original linkage which goes down to a full 90 degrees. I doubt it will be possible to all of it. Without the props on the motor pod looks like a jet. Edited By Simon Chaddock on 01/06/2012 22:23:03 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 2, 2012 Author Share Posted June 2, 2012 Finished and quickly painted. Will it be any better than before with full flap? We shall see. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 4, 2012 Author Share Posted June 4, 2012 I took a risk and actually videod its maiden. As I got the plane back in one piece, here it is. Plenty of power but seriously tail heavy. No flaps used but even so it flies pretty slowly. The nose is being extended to move the battery forward. A simple job in Deron! Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted June 5, 2012 Share Posted June 5, 2012 It's turned out to be a nice looking model Simon .It should do V Stol landings if the elevator can check the pitch change . Tom. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 5, 2012 Author Share Posted June 5, 2012 Managed a second flight yesterday evening with the extended nose. Moving the CofG forward has certainly helped. What has surprised me is how good the roll control is even with quite a bit of flap. This was always a serious weakness of the previous short span low aspect ratio version. It is surprisingly manouverable, rolls, loops and unlimited vertical. The complete absence of any torque effect is noticeable. The elevator linkage needs adjusting to give a bit more 'down' but I did achieve a full flap landing although it was right on the limit of controllability. So far so good . Next flight will be videoed! Quote Link to comment Share on other sites More sharing options...
Stefan Hafner Posted June 5, 2012 Share Posted June 5, 2012 Posted by Simon Chaddock on 05/06/2012 12:23:32: What has surprised me is how good the roll control is even with quite a bit of flap. This was always a serious weakness of the previous short span low aspect ratio version. If i remember correctly the original one had the ailerons moving down with the flaps??? I suspect that having a normal wing section outboard where the ailerons are that doesn't camber has made a the difference. Look aforward to seeing a STOL approach/landing Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 6, 2012 Author Share Posted June 6, 2012 This evening was calm enough for the STOL. An edited video showing the launch, its reasonable glide flaps up, its vertical climb capability and a full flap approach and landing. Note the landing run! It is a bit sensitive on full flap and tends t wander a bit but it does retain roll control even at the slowest speeds. It more about the pilot than the plane! Quote Link to comment Share on other sites More sharing options...
riverlandgirl. Posted June 8, 2012 Share Posted June 8, 2012 Well done, some real progress. Sounds great too! Quote Link to comment Share on other sites More sharing options...
kevin wild Posted June 11, 2012 Share Posted June 11, 2012 Hi flies lovely. nice one would it take off on ful flaps too if it had undercariage ? kev Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 11, 2012 Author Share Posted June 11, 2012 Kevin With a thrust greater than its weight and if the grrass is short enough it will take off with no undercarriage and it doesn't need full flap either! A bit more flying with full flap. In even a gentle breeze it virtually hovers but beware the ground shear! Edited By Simon Chaddock on 11/06/2012 10:29:15 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 13, 2012 Author Share Posted June 13, 2012 It just so happened to be virtually still yesterday so I was able to practise some full flap glide approach and landings. Not that easy to arrange a dead stick spot landing but it does give an idea of the low speed. Edited By Simon Chaddock on 13/06/2012 20:38:07 Quote Link to comment Share on other sites More sharing options...
riverlandgirl. Posted June 15, 2012 Share Posted June 15, 2012 Looks like youv'e got a fun little plane there! Certainly can see the speed drop when the flaps kick in.Good stuff1 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 19, 2013 Author Share Posted June 19, 2013 On another site there was a challenge to produce and video a STOL flight along the lines of those Alaska trials. The push/pull has planty of power and can fly slowly but cold not perform proper STOL without an undercarriage. Could it handle my rather rough grass? It need a bit more elevator power to hold the tail down on take off and a bit more practise to land exactly on the spot!. Edited By Simon Chaddock on 19/06/2013 18:41:03 Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 19, 2013 Share Posted June 19, 2013 Very nice that Simon , Don't know how i have missed this one . What is the power to weight ratio . Looks a lot of Fun Cheers Steve . Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 19, 2013 Author Share Posted June 19, 2013 Power to weight? It weighs 15oz and has 150W at full power so 160W/lb. The rather fine pitch props (3 blade 5x3) do give it a near vertical performance albeit at rather slow speed but thats fine for STOL. It really was put together on a shoe string using about the cheapest components you could imagine so the fact that it performs as well as it does was quite unexpected. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 21, 2013 Author Share Posted June 21, 2013 First I got the sums wrong Each motor takes 7.5A but it using a 2s not 3 so its actually 100W or 107W/lb. Second STOL flying has its dangers. As a test I took off from an undulating 'dirt' car park strewn with small sone that to scale would be sigeable rocks. No problem but the approach was resticted by a large tree with the result I went too slow and the resulting severe wing drop meant it was heading straight for the tree. In hind sight I should have left it fly in as the treet was in full leaf and less than 20' up but no I tried to do a 180. Result an even more severe wing drop (the other way). It went in almost vertical. Badly crushed and disrupted fuselage, wing tip broken off and tail boom completely dislodged. Now all repaired so I can try again! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 21, 2013 Share Posted June 21, 2013 Definitely worth resurrecting Simon. (Did you have any luck withnthe Hamilcar)? Quote Link to comment Share on other sites More sharing options...
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