2ol2flyRC Posted April 13, 2009 Share Posted April 13, 2009 Is there anybody out there ? After 5 days I was beginning to wonder. Hi Terry. At the moment I'm banned from modelling for the next couple of months, but couldn't resist starting the head. It will (one day) be finished properly, but at the moment is just roughly carved. It will be about 1 inch longer than the head drawn on the plan. Ced Quote Link to comment Share on other sites More sharing options...
Simon Parker Posted April 13, 2009 Share Posted April 13, 2009 Hi guys, The models look great! Has anyone got theirs flying succesfully yet ? Simon. Quote Link to comment Share on other sites More sharing options...
Glenn Sykes Posted April 13, 2009 Share Posted April 13, 2009 Sorry its been so long since I have posted. I have now tried four times to fly it before spending the time to paint it. The first to nose heavy, second to tail heavy, thrid and fourth had to throw myself with the left hand. I think it would have gone but very weak throw and crashed breaking the neck. The high thrust line makes it very difficult to launch and get some speed up. Will try again later in the week. Quote Link to comment Share on other sites More sharing options...
Clark Ross Posted April 16, 2009 Share Posted April 16, 2009 flew mine was underpowered glided ok but i broke something had to quit for the day. put a diferent motor on it . trying to fly it on two cell lipo instead of three didn't want to buy another battery pack haven't flown it yet with new motor. clark Quote Link to comment Share on other sites More sharing options...
Clark Ross Posted April 17, 2009 Share Posted April 17, 2009 flew mine with new motor and two cell lipo . it flys but not easy to fly you have to throw it hard and upward if you don't it will dive into ground. two thirds throttle is best less it dives more it climbs . every time i try to fly i bring back pieces it is getting to look pretty sad just about ready for the scrap barrel. i think something has to be done to the thrust line to keep it from diving. clark Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted April 18, 2009 Author Share Posted April 18, 2009 What would happen if you angle the prop 10 degrees down? would this have the effect of lifting rather than depressing the head?... regards, Terry Quote Link to comment Share on other sites More sharing options...
Glenn Sykes Posted April 18, 2009 Share Posted April 18, 2009 I tried to fly it again today. Still no luck. Flew ok from the launch eased the power on pushed the nose down so eased back a little but lost air speed and it started to drop, put some more power back on and it just dived into the ground. I have tried all sorts of configurations such as balance and prop angle, nothing worked. Ive given up ish, I have considered putting a ducted fan into the under side of the creachers belly and reshaping the head. Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted April 19, 2009 Author Share Posted April 19, 2009 I was a bit liberal with the size of the body and as I have a couple of spare 55mm ducted fan units spare I may have a look at recessing one into the back between the wings, problem is EDF's are heavier and take much bigger batteries so wing loading will go up which is a bad move with such a thin foam wing, regards, Terry Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 19, 2009 Share Posted April 19, 2009 And less efficient than a prop so could make matters worse. Quote Link to comment Share on other sites More sharing options...
Simon Parker Posted April 19, 2009 Share Posted April 19, 2009 Would the motor not be better positioned behind the COG so it wouldn't push the nose down, here at least it should push the nose up. If it glides well, then the problem surely is with the thrust line. The multiplex easy star flies well and has a good deal of down thrust with the motor positioned in a pod behind the COG. Alternatively could the pusher be dropped and a motor fittedconventionally in the nose? Quote Link to comment Share on other sites More sharing options...
Simon Parker Posted April 19, 2009 Share Posted April 19, 2009 Or would it slope soar, with the motor removed and re-balanced ? Might turn a few heads, when was the last time a dinosaur soared in a thermal !!! Edited By Simon Parker on 19/04/2009 20:37:25 Quote Link to comment Share on other sites More sharing options...
Bert Posted April 20, 2009 Share Posted April 20, 2009 'When was the last time a dinosaur soared in a thermal' Sometime Last Century Bert Quote Link to comment Share on other sites More sharing options...
Simon Parker Posted April 20, 2009 Share Posted April 20, 2009 Alright should have done my homework !!! Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted April 20, 2009 Author Share Posted April 20, 2009 Dunno about dinosaurs but the mother in law used to manage it quite well on her broomstick, that was before she got sucked into a 747's engine of course............, regards, Terry Quote Link to comment Share on other sites More sharing options...
Simon Parker Posted April 20, 2009 Share Posted April 20, 2009 Where was her thrust line and what was her prop angle ? Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted April 20, 2009 Author Share Posted April 20, 2009 Hi Simon, no need for a prop, she lived on a diet of baked beans and best bitter with the odd curry thrown in so the least said about the thrust line the better.......... you wouldnt want to follow her in traffic..... regards, Terry Quote Link to comment Share on other sites More sharing options...
Tafkam Posted April 24, 2009 Share Posted April 24, 2009 Being dinosaur-witted it can take me a while to decide on a build so I'm joining the thread late, and out-of-breath. As usual. Am actually making a pair of propelloasauri so one of my flying buddies and I can fly them in formation. Cyril designs great models, but like any self-respecting aeromodeller I just had to fiddle with it! Re-drew the wing from 'elbow' outboard to increase span to 60" for slightly better 'scale' proportions. Extra area might even confer modest soaring performance. Will maintain the designer's elliptical dihedral and thrustlines, and have tried to keep increases in wing area fore-and-aft of designed CG similar in % terms, to minimise any shift in balance. Have reshaped the front of the head to look a bit more like a pteranodon since they did have extended skulls, and intend to vacform a long spinner to complete the crest outline. Mind you, there are limits to scale fidelity - pteranodons didn't have tails. Or teeth. Mine will definitely have needle-shaped gnashers (cut from a plastic comb) installed at the finishing stage. Poetic licence. After all, what use is a 'prehistoric monster' without scary teeth? Only just begun my build - attached pic just shows the various bits mocked up to get a feel for how it looks with the revised wing. Meanwhile, a question for Terry. Hope your sciatica has abated (you have my heartfelt sympathy) and allowed you to get out and test-fly it. I wondered how effective you are finding the elevons for steering. I had toyed with doing the same thing but my worry was that the standard elevators might not have enough 'bite' in the roll axis if set up as elevons, being so short on width and sited so far inboard. Even more so since mine will have increased wingspan. I know tailerons on jets work fine, but then they normally have a lower wing/tail span ratio and a higher airspeed than yer' average pterosaur. I'd love to know how yours worked out before I cut the rudder free. If they proved up to the job I shall follow your lead and dispense with the flappy bit at the back! BTW, you are right. More trouble to attach an image with new system than before. Cheers, Iain Quote Link to comment Share on other sites More sharing options...
Landloper Posted April 24, 2009 Share Posted April 24, 2009 Iain, Thanks for the info on your stretch model propellosaurus. You are ahead of me, as I am 2 repair jobs away from starting anything new. I hope you will keep us posted as you build, maybe with pictures and plans? Thanks, Jesse Quote Link to comment Share on other sites More sharing options...
Tafkam Posted April 25, 2009 Share Posted April 25, 2009 Hi Jesse. If I waited on getting all my repairs and projects done, I'd never start a thing! Bits are made, as seen in last post, so next pic will presumably be once tail and head are permanently fixed on and model is painted. As for plan, all I did was change wing from about 1/5 span but will happily share pic if anyone's interested. Meanwhile, I realise people often start a build before joining the thread, but here are a couple of tips which might be of interest to prospective P'saurus builders. 1) Cyril suggests fitting the underlayer first, followed by the upper layer. I reckoned it might be difficult to do a good job of attaching the underlayer to a relatively floppy wing without losing track of the correct reflex or dihedral, so I built a simple jig to support the reflexed wing part the 'right way up'. I put the first wing component on the jig and propped the wings up to the correct dihedral. I then added the upper layer and the spine first and weighted them in place till set. Spine is not mentioned in the text or on the plan, but shown in the photos and definitely a Good Thing. This stiffened it all up and locked in the reflex. When it came to adding the underlayer I used slow epoxy. I aligned the body then put it all back on the jig and weighted it in place. This allowed me to work outwards along the armbones, bringing them up into contact with the underside of the wing and re-establishing the elliptical dihedral as I went along. I taped the joint at regular intervals and propped up the wings to hold shape until set. This seemed easier to me than raising the centre section off the bench so as to build it upside down, or assembling it all 'in mid air'. Especially with the increased span of my version. Once set, everything was 'as per', and it should be adequately stiff once the glass re-inforcement goes on. Note that a glass wrap on the LE is called for on the plan, but once again not mentioned in the text. 2) I'm sure one could make a nice job of the claws using the recommended car body filler (or possibly Bondaglass SL?), but it can be messy stuff to work with and I worried it would be unyielding if knocked and might transfer damage to the surrounding depron. It might also be prone to cracking and flaking off. I used Polymorph. This excellent product comes as white granules which melt in hot water to form a clear gel. It then has a consistency somewhere between softened wax and plasticine, and can be formed by hand. Once cool it turns white again and has the properties of a nylon moulding. Useful for any number of modelling jobs. You can even make your own 'nylon' control horns if so inclined! The finished claws are rigid, yet flexible enough to avoid damage. Polymorph is available from Maplins and elsewhere. Cheers, Iain Quote Link to comment Share on other sites More sharing options...
Landloper Posted April 26, 2009 Share Posted April 26, 2009 Great ideas! Thanks, Iain - and thanks to all of you who take time to share your experience, I am going to build one of these things. Jesse Quote Link to comment Share on other sites More sharing options...
Terence Lynock Posted May 2, 2009 Author Share Posted May 2, 2009 If you want to strengthen and properly applied stiffen the wing use fibreglass reenforced packing tape, I use stuff I buy off eBay that is usually used to protect cricket bats. A 10 metre x 25mm wide roll is only about £1.50 and it is very sticky, works great for protecting leading edges and another type is 1/2'' wide parcel tape that is also fibreglass reenforced and you can get that for as little as 50p a roll 50 Mtre long off eBay too. The 1/2'' is good for running along the underside of wings to help stop upward flex and as it weighs very little it is most useful stuff, regards, Terry Quote Link to comment Share on other sites More sharing options...
Tafkam Posted May 2, 2009 Share Posted May 2, 2009 Great idea Terry. I used 2 lams of very L/W glass with some carbon tows between - but only because of my 50% span increase. Certainly did the job, but reinforced tape would probably have done more than adequately. Have used it on enough slope soarers - don't know why I didn't think of it at the time. Dohhh! Still keen to hear how your elevons are working out. Getting to 'decision time' for parting the rudders on my pair! Cheers, Iain Edited By Tafkam on 02/05/2009 14:39:52 Quote Link to comment Share on other sites More sharing options...
2ol2flyRC Posted May 15, 2009 Share Posted May 15, 2009 Iain, I think that you have managed to kill this thread stone dead. It looks as extinct as a fossilised Pterry. I believe it is an acquired knack. Cheers, Ced Quote Link to comment Share on other sites More sharing options...
Landloper Posted May 15, 2009 Share Posted May 15, 2009 Some of us have to lurk and plan a bit before jumping in. Iain and others have helped me out, and I will be building one of these monsters soon. Lets keep this extinct bird-thing alive. Jesse Quote Link to comment Share on other sites More sharing options...
Marcos Piazzon Posted May 15, 2009 Share Posted May 15, 2009 Well, I have to say that Iain contact me by mail and he send me the magazine with the original plans by postal mail. I´m still waitng for the postman but I think in a week or two the magazine will arive. We exchange a copule of mails talking about construction materials and I'm looking for a replacement to the blue foam. That kind of styrofoam is unaviable in ths country so If you have any idea It will be great. To make the head of the propellosaurs I think It will be the most difficoult task for me. For the moment I´m reading your posts and trying to lern about this project. Best regards and special thanks to Iain and Cedric. Marcos Edited By Marcos Piazzon on 15/05/2009 21:29:17 Quote Link to comment Share on other sites More sharing options...
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