Spice Cat Posted July 10, 2011 Share Posted July 10, 2011 Maidened my BH Bird Dog today for all of one second. She unstuck ok but then first the right, then left then right wing dropped the latter causing a cartwheel into the ground. Nose was broken off, wing end was broken and some control surface damage done. Possibly caused by a tip stall as I forced her airborne too quickly. This is the first time this has happened to me on a maiden and five other models I have assembled have flown from the off. Strangely enough I saw the funny side of it and sat down to ponder the repair. The more I inspected the damage, the more I could see the repair options and began to look forward to the job. (Must be old age) The intention is to do the basic repair, get her airborne and then apply the finishing touches providing she flies of course A funny thing happened on the way back however, the outside of the cowl became coated in Magnum Fuel which pickled the paint. A respray job is now also in order. I would have thought however such paint would have been resistant to such things. Oh well.... Quote Link to comment Share on other sites More sharing options...
Gary Binnie Posted July 10, 2011 Share Posted July 10, 2011 I have to ask if the ailerons were working in the right sense?Seems very strange that a high wing model (naturally stable type) would give trouble.We had a model presented for maiden flight with the ailerons reversed last week, the test pilot (not the builder) spotted it straight away.GB Quote Link to comment Share on other sites More sharing options...
Alan Cantwell Posted July 10, 2011 Share Posted July 10, 2011 sorry for your first flight loss, did you go to aileron at low speed? you should have differential in the ailerons, down going one creates drag, etc, hope you get it fixed, orrid thing on a maiden Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 10, 2011 Share Posted July 10, 2011 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 11, 2011 Author Share Posted July 11, 2011 Ailerons were OK, there was a slightly gusty crosswind now I think of it. I will check the CG again but I did put about six ounces of lead up the front to balance her. Thanks for the advice. Still gutted. Quote Link to comment Share on other sites More sharing options...
Gary Binnie Posted July 11, 2011 Share Posted July 11, 2011 Only other thing I can think of is that 'taildraggers' are not happy taking off in a three-point attitude, tail has to be well up on the take-off roll and then a little tweak of up elevator unsticks it. Crosswinds and low level turbulence can make the best model (and full-size) misbehave. I have not experienced the 'gutted' feeling lately, must be due a crunch! Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted July 11, 2011 Share Posted July 11, 2011 Tough luck SC. Given the ailerons are OK its probably a combination of a bit too slow and a bit too "nose up" so she's only been flying marginally. As soon as you put the aileron in that finishes the job off and that wing tip stalls. Ah well - our hobby is full of painful lessons like that I'm afraid! Still you seem to have a good healthy appetite for the repair . You'll soon have it back on the strip again. Just remember next time a bit more speed and let her get up onto the mains before taking off. Funny thing about maidens, you're always a bit worried and tempted to be a bit timid about committing. But actually the best plan is 100% committment, always try to use a bit more speed on take off for a maiden rather than less - as you know well speed and height are our friends! BEB Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 11, 2011 Author Share Posted July 11, 2011 Thanks for this. It's always strange that almost 24 hours after a "traumatic event" you get bursts of amazing clarity. Yes I believe she did have a high nose attitude and I unstuck her a tad early. Also this is the first model I have flown with a tapered wing which as I understand makes them a bit slippery. What worries me now is that I have a Sparrowhawk under construction too. On maiden, I promise that one will hit Mach 1 before I feed in the Up. I have just spent a very happy hour in the shed re building the wing tip and the original plan still holds; enough repairs to get her airworthy and maidened hopefully this Sunday. I'm still a little puzzled as to why that paint should have pickled on the cowl. Also I am chickening out and ordering a new windscreen from Ripmax (I hope). I'll let you know how I get on. Gary as for the "gutted" feeling, I hope you don't have to put up with it but I have found prescription levels of Budweiser helps. Quote Link to comment Share on other sites More sharing options...
Gary Binnie Posted July 11, 2011 Share Posted July 11, 2011 Nah, Bud gives me an enormous headache!! There is an Austrian beer called 'Zipfer' that I could not induce a hangover from (no matter how hard I tried!).I've crashed a 12 ft span glider, twice in the last year, I was going to throw it in the bin but repaired it and it flew fine last week (I'm watching it closely though!!). I won't say who it's designed by but he has something to do with Wot 4s! My E-Flite Fokker DVII bit the dust from a low turn in calm conditions, no apparent reason for it, just slid into the ground. Tiny bit bent and flying happily again. I keep the expense down with my models so the only gutting comes from the manhours (which are free!). A 'gutting' that I can remember was the demise of a CO2 powered Hacker Tiger Moth, a lovely model that got crushed in the back of a transit van by something bigger moving about. That was 1997, must get another one. GB Quote Link to comment Share on other sites More sharing options...
Alan Cantwell Posted July 11, 2011 Share Posted July 11, 2011 by ailerons where ok, can i take it you did have differential in them? you really need at least twice the up, than down for starters, hope you get it back together ok Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 12, 2011 Author Share Posted July 12, 2011 Seen and noted. The differential will be put on later. The repairs are actually going suspiciously well. A further post crash enquiry has revealed that I had not fitted the prop I though I had and the poor old .61 was chucking a 14x7 around. Only myself to blame. A few photos of the mangled wing tip two hours into repair. Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 20, 2011 Author Share Posted July 20, 2011 Essential repairs completed and back to the strip today. She took off into a very slight breeze but flew a little lumpy as she was missing some of her body panels. Unfortunately, the cockpit cover, which I was holding on with magnets, gave up the ghost and I decided to fly without it. This appears to have been the last straw aerodynamically speaking and she crashed on the two subsequent take offs. Back to the bench for some minor repairs and the magnets replacing with bolts. Other than that, I am heartily relieved she flew. Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted July 26, 2011 Author Share Posted July 26, 2011 Repairs completed, off we went again. This time I had moved the CG slightly forward and on roll out; achieved what I thought was a good speed. Wheels up and she went over on her left again. Broken fuze and a few other bits. I have consigned her to the loft for now and will keep her as a repair project. But, I will not be beaten..... Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 26, 2011 Share Posted July 26, 2011 i have exactly the same problem with a scratch build of mine.it will take off but rolls to the left and digs in.fortunately mine is easily repaired. i hope you sort out the problems. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted July 27, 2011 Share Posted July 27, 2011 My E Flite DH Beaver can drop it's left wing if pulled off too quickly, but I think it's more to do with the torque reaction from the prop, I now take off with less power, applied gradually, and a longer run and apart from looking more realistic it takes off with the the wings level. Other thing to do as well is to dial in some aileron-rudder mix. Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted September 5, 2011 Author Share Posted September 5, 2011 I have almost completed repairs; again. One of the elevators was smashed beyond repair and I was faced with trying to replicate the corrugations to make the new one match. I decided I could not and cut the undamaged one off, replacing both as you can see. Now awaits the covering. Quote Link to comment Share on other sites More sharing options...
David Ashby - Moderator Posted September 5, 2011 Share Posted September 5, 2011 Nicely done Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted September 5, 2011 Author Share Posted September 5, 2011 Praise indeed. I hope to God she flies...... Quote Link to comment Share on other sites More sharing options...
Seamus O'Leprosy Posted September 5, 2011 Share Posted September 5, 2011 I agree with Frank above I always mix in a good bit of aileron/rudder mix for the first flights. At least until my thumbs catch up with my brain. Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted September 17, 2011 Share Posted September 17, 2011 I've got one, flys well, now. On the first flight it was way tail-heavy, also on full power the nose pitched up. Had to use full down trim and half forward stick to stop it going over. Also on turns, needs loads of ail/rudder to boot. (now with 45 % ail/rudder mix.) Flew it round for a few mins, struggling, but rather than land it, got it sorta stable, then landed. Ok. Back in the workshop I moved the battery right forward, and put more down thrust and more right thrust. Flew much better, and even chucked it round, doing rolling circuits on the 2nd flight. It;s got a SC91FS, so over-powered, but needs a heavier engine. I don't know how and why you kept crashing yours, but hope it goes well, when repairs are complete Actually, the P-51 in the background was a repair after black wire lost radio. Wings snapped in three, and nose ripped off. Recovered after repairing, now a 2nd life after 10+years as Miss America. Now it's a "Moonbeam Mc'swine" Edited By Paul Marsh on 17/09/2011 21:58:19 Edited By Paul Marsh on 17/09/2011 22:03:04 Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted October 16, 2011 Author Share Posted October 16, 2011 She's Up . The weather today was perfect, a slight breeze down the strip and a clear sky. I handed the controls over to one of the best in the club the prayed to whichever God covers aviation and away we (he) went. She came unstuck and wobbled about a fair bit but once airborne, the pilot commented she did not seem to have much power. Back on the ground for a swap of a prop and a discovery that the throttle was not opening fully. Flight 2. A total non event. She went down the strip, took off and flew well, like a model should. I am very relieved by todays events and all this may have stemmed from too low power, to big and coarse a prop followed by a tip stall. I have however yet to take her up myself........... Many thanks Nick. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 16, 2011 Share Posted October 16, 2011 Glad to hear that went well SC. As you say it does sound like a lack of ponies at the pointed end led to a lack of airspeed at lift off, big angle of attack - tip stall...and the rest is a painful memory. But at least she's up now. I'm sure you'll get on fine with it now! BEB Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted October 17, 2011 Share Posted October 17, 2011 What engine do you have in it? With the 91, is goes vertical, and 1/2 throttle is enough for level flight. Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted October 17, 2011 Author Share Posted October 17, 2011 She has an SC61 two stroke which was the top end engine for the job according to the blurb on the box.. I would love a four stroke in there as you say she needs a heavier engine. That way I can get rid of the half a pound of lead in the front. Regards. Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted October 17, 2011 Share Posted October 17, 2011 It would have more power/weight ratio, by replacing lead with horses. Added to that, would sound better, and have more usable torque, which a 2 Stroke doesn't have. The engine I bought was from a 2nd hand, for £45, including engine mount/prop. bargain. Actually, it's an Magnum 91, not an SC. Still same engine, though... Edited By Paul Marsh on 17/10/2011 21:48:31 Quote Link to comment Share on other sites More sharing options...
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