ZK BAP Posted October 21, 2013 Share Posted October 21, 2013 Needle valve gone....lol Quote Link to comment Share on other sites More sharing options...
Mart49 Posted October 21, 2013 Share Posted October 21, 2013 Might be interesting to let us know what actually happened. Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 21, 2013 Author Share Posted October 21, 2013 Calm day with just the odd gust, but all over the place. One moment the wind is 1 direction, then bam, complete opposite or 90 deg. caught me out, dipped a wing on landing. The Beaver wing is not very forgiving and has a wee habit of tip stalling. The pilot error comes in because this was the second apprch as the first was abborted due to wind....i wasnt ready for the cross and bam, ground....the wind can be nasty sometimes lol Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted October 21, 2013 Share Posted October 21, 2013 Posted by ZK BAP on 21/10/2013 09:06:10: Needle valve gone....lol looking at the remainder, I think that may be the least of your problems... Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 21, 2013 Share Posted October 21, 2013 I agree - the spar breaking at a rib like that is always a tricky and time consuming repair. It can be done of course - just needs care and patience! Was it definitely a tip stall? Or did the cross wind just get under it at the wrong moment? BEB Quote Link to comment Share on other sites More sharing options...
Ruprect Spode Posted October 21, 2013 Share Posted October 21, 2013 There was mild moist air with a cold front coming through at the weekend, resulting in a high adiabatic lapse rate, lots of rising air and falling air all contributing sudden wind direction and speed changes. If you watched a developing CB coming through and understood what was likely to happen you could have made decisions more conducive to model safety. Learn some meteorology principles. Quote Link to comment Share on other sites More sharing options...
John F Posted October 21, 2013 Share Posted October 21, 2013 Nice advice there Ruprect; if in doubt watch that warm moist air and beware of your cold front. Quote Link to comment Share on other sites More sharing options...
john melia 1 Posted October 21, 2013 Share Posted October 21, 2013 i had an adiabatic lapse the other night Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 21, 2013 Author Share Posted October 21, 2013 i think it was a tip stall, but cant rule out other possibilities like the wind just getting right under a wing, i am kicking myself now for not being aware. I may just build a complete new wing as i dont think i would ever trust the repair where it would be. Im going to get the old trainer going again so i can practice this crosswind thing. good advise on the meteorology, a thing that tends to get over looked. With summer coming in we get alot more warm winds accross the strip. unfortunatly i wasnt the only one that day to have probs with wind, two others also ploughed into the ground. Quote Link to comment Share on other sites More sharing options...
RB Posted October 21, 2013 Share Posted October 21, 2013 Looks like a very typical 'Spektrum' crash to me! Quote Link to comment Share on other sites More sharing options...
Bandit Posted October 21, 2013 Share Posted October 21, 2013 Why would it be a typical 'Spektrum' crash? Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 21, 2013 Author Share Posted October 21, 2013 Radio was fine. I have had no probs with spekky. I put it down to my own fault lol. Quote Link to comment Share on other sites More sharing options...
Shaunie Posted October 21, 2013 Share Posted October 21, 2013 I had a "Spektrum crash" the other day. The plane I was flying was on a cheap 35 meg set without expo if I'd got it on Spektrum with some expo I wouldn't have run out of up elevator, ergo it's Spektrums fault I'd been having control issues and although I thought it was paranoia I came in anyway, rushed and botched the approach and ran out of up just before the threshold. Strangely, when checking out the plane after converting to 2.4GHz I had no ailerons, extension lead open circuit on the ground line. Seriously, why the Spektrum bashing, mine's been brilliant. Shaunie. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 22, 2013 Share Posted October 22, 2013 Guys can we not turn this into a "Spektrum Post Mortum" thread please - it really makes Mr Bott very cross! And it doesn't help my day along either! I'll give Rob the benefit of the doubt - that it was intended "tongue in cheek" and not as a serious remark. So let's leave it there and get back to the OP's original point. BEB Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 22, 2013 Share Posted October 22, 2013 Cross wind landings are something you have to work at! How comfortable are you using the rudder? Without that you'll never perfect landing cross wind. If you do feel that you need a bit of "rudder practice" shout up, I know a couple a couple of really good exercises you can do to work-up your skills in that department! BEB Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted October 22, 2013 Share Posted October 22, 2013 shout out then beb, i hate crosswind landings and take offs Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 22, 2013 Author Share Posted October 22, 2013 yes from now on ill only fly the trainer and not my scale models in a crosswind untill i perfect that rudder. i still ponder the tip stall thing. a wing did drop rather suddenly and no ammount of rudder or aeilrons was going to save me. maybe the shift in wind created enough 'drop'? I think with weather being unpredictable i should just be a bit more aware of potential shifts in air flow. really something i have not thought about too much in the past. Quote Link to comment Share on other sites More sharing options...
John F Posted October 22, 2013 Share Posted October 22, 2013 You'll go mad trying to work out what happened in such circumstances. The thing is it could just as easily be due to the random crosswinds as it could to a tip stall but the crosswind sounds much more plausible if you did not notice any difference in the controls. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 22, 2013 Share Posted October 22, 2013 i had a similar 'oops' last year when flying my Astro-Hog I had got the model tracking straight in a blustery cross wind, but with an engine running decidedly sick. Instead of backing off, I decided to risk it with the inevitable result that the engine died just after lift off and a cross wind gust hit me. left wing goes down, try to correct with right aileron was probably the worst thing I could have done, right rudder would have been the correct answer. The model stalled quite violently and flipped over very fast. Fortunately damage was minor to middle - a broken tailplane, broken aileron and the wing mounts came out of the fuselage. It was very embarrassing thought, over 100 people were watching at the time... Ian Jones got the moment of impact on his 'kiss of death' camera, but fortunately, the image was worse than BEB's standard of blurred photography Martyn Edited By Martyn K on 22/10/2013 14:49:02 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted October 22, 2013 Share Posted October 22, 2013 Posted by Martyn K on 22/10/2013 14:47:56: Ian Jones got the moment of impact on his 'kiss of death' camera, but fortunately, the image was worse than BEB's standard of blurred photography Martyn Edited By Martyn K on 22/10/2013 14:49:02 LOL! OK as I say you'll never master a crosswind landing unless your general rudder skills are up to scratch. So, some things you can do to practice controlled use of the rudder! Flat turns - these are were it all begins, turning the model whilst keeping the wings level. Suppose we want to turn right; put in plenty of right rudder, the aeroplane will probably start to bank right - especially a trainer with dihedral - so you have to add left aileron. You add just enough aileron to keep the wings level. You should now be turning to the right but with the wings level. But, you will almost certainly also be descending - maybe at quite an alarming rate! Why? Becuase you are side slipping and the air is not following over the full (sideways on) area of the wing - think of it as if the model's wings had suddenly decreased in size! Now at this point all your instincts will tell you to pull back on the elevator - don't do it!!! That way lies disaster - rudder and ailerons crossed left and right, high angle of attack - its got spin written all over it! Instead just open your throttle a tad - the increased airspeed will restore your lift. Once you can do a basic turn like this you'll find that you can "trade off" rudder and aileron against each other - making the turn tighter or wider as you wish. Now try flying a complete circle that way, then a figure 8 - that's trickier than it sound TBH! This is a difficult exercise for mode 2 flyers - many of whom have a "lazy left hand" - between balacing the rudder against the aileron and adjusting your airspeed with the throttle these flat turns will get that left hand moving! Now the cross wind landing,....first of all as the model comes in on approach it will be skewed sideways to the apparent direction of travel. If the wind is towards you the tail will be sticking out towards you as well. At this point lots of people say "Oh look at it side slipping" - its not side slipping at all. Its perfectly happily lined up with the on coming air direction. The wind is from the far side of the strip - the model is flying down the strip say left to right - to the model it feels like the wind is coming from approximately the 10 or 11 o'clock direction (where 12 o'clock is striaight ahead) - just off the strip axis. Exactly where it appears to be coming from depends on the relative size of the wind speed and the model's speed. If they were equal the wind would feel like it was coming from 45 degrees - sort of half past ten! If the model's speed was zero it would feel the wind from the same direction as you do - ie sideways on or 9 o'clock relative to the model. So, the model is lined up with the apparent wind direction and is quite happy with that. But - you can't land it like that because the wheels aren't in line with the model's direction of travel. And this problem is going to get worse as you slow down to land. As you slow down the model feels the wind moving more and more round towards the 9 o'clock position and it will want to skew round to meet it head on. This effect is slightly reduced in practice because wind speeds generally drop as we get lower - but the basic pattern remains. So what do we do? Well the first answer is nothing. Just let the model come down on appraoch - let it be skewed as it wants to be. Then, just at the flair, use the rudder to striagthen up. (Sticking with our "wind is coming towards you" scenario and that we are landing from the left) - you'll need right rudder to straighten up. But as we found that will bank the wings right and we realy really don't want that because it encourages the side wind to get under the high left wing and that way lies a wing strike - so we need a touch of left aileron to counteract this and keep the wings level - maybe we even want the left wing down slightly so maybe we add even a bit more left aileron. Now we must be careful - we need to keep a bit of power on because, whilst we weren't sideslipping on the approach, we most certainly are now and she'll come down with a thump due to the sudden lose of lift if we aren't careful. So keep a bit of power in hand to check the very final rate of descent. You can't do a "cut and glide" cross wind landing! Hope this helps BEB Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 22, 2013 Author Share Posted October 22, 2013 Thanks BEB, that sounds like a great way to practice. I will try that flat turning this weekend with the trainer ( only 1deg dihedral) see if i can master it. Quote Link to comment Share on other sites More sharing options...
Shaunie Posted October 22, 2013 Share Posted October 22, 2013 Thank BEB, I'll read that again and again. To reduce it to its logical minimum: Aileron into the wind and rudder to correct the track onto the runway? My other question is this: there is a great amount of talk about "weathercocking into the wind" surely this only happens on the ground run? if the plane is in the air it will always travel straight ahead unless there is a control input surely? The rest is how we see the planes track because of the off-track component of the sidewind that we on the ground cannot see. If this is the case then I think we automatically weathercock the plane into the wind as part of the piloting process i.e to correct the track to our desired one. Does that make sense? Just keen to work this out in my head because my crosswind landings are more by luck than good judgement. Shaunie. Quote Link to comment Share on other sites More sharing options...
ZK BAP Posted October 23, 2013 Author Share Posted October 23, 2013 Happy to report that i managed to quickly fix the needle valve problem. i used a needle from an old os 20 kicking round in the shed. the 2a and 3a carbs take the needle set up ) I also popped into my lms and got hold of brian from airsail and a new cowl etc is on the way. kiwi service is wicked lol....got to say that lol....anyways, beaver will be flying again soon. However, i will not fly her in a crosswind dull day again. Also, brian made a limited run of the small Auster. Only 1kit left. thanks for the input and advice guys, really appreciate it. Regards ZK BAP Quote Link to comment Share on other sites More sharing options...
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