Smurphboy Posted June 25, 2009 Share Posted June 25, 2009 Hello all, First time poster here so be gentle on me! I've just bought and built a Flyingwings V-Trainer and think I've got it trimmed out nicely. (lovely aircraft by the way) I've been doing circuits and tonight it was pretty gusty (a/c was struggling to make progress upwind when the gusts were strong), and I had a real problem turning cross-wind after my downwind leg. As I turn, any gust tightens my turn and dives the aircraft quite dramatically. Is that normal? Am I doing something wrong? I've only had one prang as a result (mostly me being heavy on the throttle trying to recover the dive) but I'm not sure it isn't a trim or other issue. All help welcome! SM Quote Link to comment Share on other sites More sharing options...
Dusty Posted June 25, 2009 Share Posted June 25, 2009 Flying in the wind is always go to be a problem, especially a cross wind! Flying in a crosswind would require the stick being pushed "into" the wind for the aileron and using the rudder to keep the nose straight! There is a article here on this forum here about x wind etc...?? Understanding the priciples of flight would answer all your questions and make you become more vigilent of what your flying machine is doing! By the sounds of it you were on the high end of the flight envelope of the model and nearing a disaster (IMO i am not familiar with this type)!! Quote Link to comment Share on other sites More sharing options...
Smurphboy Posted June 25, 2009 Author Share Posted June 25, 2009 Posted by Dusty on 25/06/2009 20:25:15: Understanding the priciples of flight would answer all your questions and make you become more vigilent of what your flying machine is doing! By the sounds of it you were on the high end of the flight envelope of the model and nearing a disaster (IMO i am not familiar with this type)!! I think I understand the principles of flight (have an Aero Engineering degree) but I wasn't expecting the a/c to behave like that. My thought was that the dihedral of the wing should prevent a spiral dive but that is how it appeared to behave. Conversely, the wind does cause the high side of the wing to balloon up into the wind so made its a feature of the a/c. Has anyone with experience of this model had a similar problem? Dusty: You do make a good point about nearing disaster - I wasn't flying nearly high enough to recover from the resulting dive! Lesson reidentified... Quote Link to comment Share on other sites More sharing options...
Dusty Posted June 25, 2009 Share Posted June 25, 2009 Smurphboy I did not know you had a Aero Engineering degree and did not mean to insult your knowledge, I am a redundant CPL pilot if you want to call it that? models and full size generaly behave in the same manner! It came accross that it was to windy to fly the type of model? IMO! Quote Link to comment Share on other sites More sharing options...
Smurphboy Posted June 25, 2009 Author Share Posted June 25, 2009 Posted by Dusty on 25/06/2009 21:41:48: Smurphboy I did not know you had a Aero Engineering degree and did not mean to insult your knowledge, I am a redundant CPL pilot if you want to call it that? models and full size generaly behave in the same manner! It came accross that it was to windy to fly the type of model? IMO! No worries. You might be right about the wind though - thinking back, I was really struggling upwind and really throttling back downwind so its possible I was close to the stall and the gust just caught me out. Theory and practice are two different beasts! Thanks for the help. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted June 25, 2009 Share Posted June 25, 2009 Two things to remember here.....1, I think the V trainer is a rudder/elevator model....these always turn a bit slowly into wind....the rudder doesn't actually turn the model...it yaws it & the dihedral actually turns it so you are not directly controlling the model but awaiting an aerodynamic force to do it for you. 2, the model is not concious of the wind...it is just flying in air. The air is moving relative to the ground & hence from the ground the aircraft seems to behave oddly....since the pilot (you) is fixed to the ground you see the aircraft fairly scoot downwind...panic & try & haul it around the turn....result the aircraft loses airspeed & stalls even though from the pilots point of view it still seems to be moving pretty quickly (high ground speed). Windy conditions with Rudder/elevator models are best avoided until you have a bit of experience.....they are very sluggish to respond & you need to fly more by anticipation....not easy when your a beginner!!! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 25, 2009 Share Posted June 25, 2009 Smurphboy "Really throttling back" down wind is a sure recipe for disaster! Remember in a wind the model only appears to speed up and slow down as it is viewed from the ground, what it needs is a constant airspeed. So, if properly trimmed, leave it alone to speed up and slow down as it wants but its wise to call it a day if the wind speed reaches half the model speed. To make matters worse it is quite likely that gusts (or turbulence) exist in windy conditions so reducing airspeed is even more dangerous. It is possible to fly in really strong winds (ask the "slopers") but you have to know what you are doing. Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted June 25, 2009 Share Posted June 25, 2009 I'm going to disagree with you Steve. Try flying a light aircraft in the circuit with a strong crosswind. The symptom Smurphboy described happens all to often and can result in the unwary spinning into the deck! Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 25, 2009 Share Posted June 25, 2009 Doug, I don't think you need to disagree with Steve (and Simon) - in my opinion he is totally correct! The root cause is lack of airspeed. Something I emphasised when teaching glider pilots about manoeuvering close to the ground or low thermalling was the temptation to subconsciously reduce airspeed due to the apparent increase in speed when turning downwind when near enough to the ground for the groundspeed changes to be noticeable. Models suffer from the same effects and this, coupled with the gustiness close to the ground (where our models fly their circuits) in a strong wind, plus the increase in stalling speed when turning tightly is a recipe for a stall/spin scenario.Edited By Martin Harris on 25/06/2009 23:42:57 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted June 26, 2009 Share Posted June 26, 2009 I'm sure you are right Doug.......any aircraft will behave in this way if the airspeed is too low it will stall & potentially spin into the ground.....the problem is a lack of airspeed. Judging it in a model is very difficult because we are stuck on the ground so all we can see is the ground speed. I have a pilots licence (sadly lapsed) & I know that the ground appears to do some very odd things when viewed from an aircraft....obviously we have an ASI on board so we can make sure our airspeed is correct....much harder to judge on a model. In aviation speed & height are our friends & can generally be interchanged. This is true of models & fullsize. Quote Link to comment Share on other sites More sharing options...
Ross Clarkson Posted July 5, 2009 Share Posted July 5, 2009 Great post. On my second flight the other day, i had similar characteristics. It was quite blustery and it was my first flight on my own in medium winds. I did notice myself pulling the trottle back dramatically on the downwind leg as i i thought i was going to fast. Airpseed/Groundspeed didnt really cross my mind at this point as my brain didnt think quick enough. I then noticed, like Smurphboy, that on the base leg turning into wind i had to apply a lot of up elevator and throttle as my airspeed was obviously dramatically slow and i could see the airplane wanting to stall or spin in!! Educational post this as i now know to keep my airspeed up even if it does look scarily fast! Cheers, Ross. Edited By Ross Clarkson on 05/07/2009 01:58:10 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted July 5, 2009 Share Posted July 5, 2009 Good man! Quote Link to comment Share on other sites More sharing options...
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