Glenluce and Galloway Flyers
Spinning
Some people tend to get themselves in a spin when the subject of spinning a model comes up, however, I hope to be able to show you that spinning a model and recovering from the spin in a relaxed and confident manner that does not result in the demise of the aeroplane, a set of bicycle clips being required or a dose of Imodium to prevent ' liquid Panic!' What is a spin?........a spin is when the model is in a stalled condition and is then made to rotate around its centre of gravity by the application of rudder (yaw) to induce a spiral descent whilst maintaining the stalled state. How is it different from an induced spiral dive?........in a spiral dive, the model (wing) is not stalled. How is it different from a tip stall? (Big digression coming here!)..... In a tip stall, usually one wing stalls first ...(this is a beak down of airflow starting from the tip of the wing and quickly moving along the whole wing) slightly before the opposite wing and this can cause the model to stall on one side and enter a spiral or it can cause the model to ' tuck under' with the unstalled wing as it rapidly experiences a combination of a sudden and rapid loss of lift and / or a negative angle of attack due to the stalled wing and associated rapidly increased drag...it then 'digs in and bites' with the result that the model will ' flick out' in the opposite direction to the initial stalled wing that easily lifts and flips over because it is in a 'bubble' of turbulent air with no smooth airflow. This is most evident in models with high wing loading. (That is less wing area supporting more mass/ weight.) That is why you get a tip stall in heavier, more aerobatic aircraft with narrower tips and reduced wing section.....the tip has less ability to support weight and maintain flight due to reduced area and a reduced wing section, it needs more airspeed to maintain flight. This can be seriously exacerbated and compounded by a model that is turning. The inboard wing is moving slower relative to the outboard wing and is more readily prone to tip stalling. This catches out hundreds of model pilots on every field in every club across the whole country as they try to turn too sharply or steeply whilst having too slow airspeed. The result is a stalled model in a spiral dive.... panic.......unsure what to do.........waggle everything.......smack!How do you avoid it? SIMPLE.....DON'T FLY TOO SLOWLY OR TRY TO TURN TOO TIGHTLY OR YOU WILL LITERALLY STOP FLYING....wings need smooth airflow to generate a difference in pressure that creates lift to make the wings 'fly.' Different types of wing need different amounts of forward motion through the air to maintain flight. Trainer wings are good at avoiding stalling and are able to fly slowly in slow moving air, ideal characteristics for the learner pilot! Other wings are far less tolerant and won't put up with inexperienced pilots trying to 'fly' them like a trainer wing. It is worth noting though that even the most benign, friendly little trainer wing will eventually run out of steam, give up and stall! It is all about balance once again, maintain flight by somehow developing and maintaining airspeed. The energy for this comes usually by either using a motor or gravity (e.g. in a glider you build airspeed by allowing gravity to take the driving seat for a while!)Back to the spin....... (eventually!)So, to enter a spin when you mean to.....! .....you must allow the model to slow down and lose airspeed to the point where the wing stalls uniformly. ...a word of caution...does this at height. (Obvious statement!)Until you know what you are doing, ALWAYS do this into wind. Don't force the stall by pulling in more and more up elevator at speed with the nose getting higher and higher and the model climbing. Take your time to allow the model to slow down and stall. In a comp, if the model pitches up before the stall you lose mega points. The objective is to keep the model as horizontal as possible, even with bags of up elevator applied and held in. When the model stalls, it should nod and dip its nose from straight and level. It will usually be stopped or almost stopped relative to the ground. This is the exact point, after the stall, , NOT BEFORE, where you smoothly apply full rudder....do this in the direction that is away from yourself so the model spins outwards, not inwards. If the wing is stalled and rudder applied, the model WILL begin to spin. Different models spin in different ways; some more slow and sedate others snappy and more violent. Some models need a little aileron in the direction of the spin to help them get going but not big bucketful’s of aileron or the spin will turn into a spiral dive very quickly. I won't at this point go into how you manage and alter the rate and flatness of the spin. What you need to know next is how to stop the spin and get the model flying again. To resume flight... First of all neutralise all of the controls (you will have full up elevator and full rudder on and holding it as the model is in the spin.) Allow the spin to slow down on its own and to help it bite and begin to fly again, you may need to nudge a slight amount of down elevator as you smoothly apply some throttle. The combination of power from the engine along with gravity acting own the model with its nose down will quickly make the wing begin to fly again. All you need to do then is smoothly pull back on the elevator to stop the descent and 'fly' out. Until you can control the direction of exit by your timing, you need to be prepared for the model to exit in any direction and sort it out from there. Simples! So, go and give it a go, but don't go at it without having thought it out fully first. Think about what you are going to do and what you will do to manage the aeroplane at all times. If you follow these steps you won't have any nasty surprises. ...I am always happy to demonstrate or hook up a buddy lead as back up for your first attempts. ADDENDUM. I left out the following so as not to confuse initial attempts, so do not try the tips below till you are confident with the procedures described above. Full up elevator will keep it spinning and stalled, but when you get more into it, you can control the flatness or steepness of the spin by a combination of the amount of elevator you use combined with the amount of OPPOSITE aileron to keep the spin flat. You can speed it up or slow it down by adding or reducing rudder and to a lesser extent aileron. The other major factor in successful spins is the CG position. A more rearward CG let's models stall and spin more easily. If the CG is a bit too forward, it can be very difficult to induce a proper spin because you can't get it to stall as easily and it is hard to get the nose up..... That is really about the angle of attack of the wings. If you can't increase the angle of attack easily because of the nose dropping due to a forward CG, that again helps the model resist a stall and subsequent spin. I hope this is helpful. Always happy to clarify points etc
Glenluce and Galloway Flyers
Spinning
Some people tend to get themselves in a spin when the subject of spinning a model comes up, however, I hope to be able to show you that spinning a model and recovering from the spin in a relaxed and confident manner that does not result in the demise of the aeroplane, a set of bicycle clips being required or a dose of Imodium to prevent ' liquid Panic!' What is a spin?........a spin is when the model is in a stalled condition and is then made to rotate around its centre of gravity by the application of rudder (yaw) to induce a spiral descent whilst maintaining the stalled state. How is it different from an induced spiral dive?........in a spiral dive, the model (wing) is not stalled. How is it different from a tip stall? (Big digression coming here!)..... In a tip stall, usually one wing stalls first ...(this is a beak down of airflow starting from the tip of the wing and quickly moving along the whole wing) slightly before the opposite wing and this can cause the model to stall on one side and enter a spiral or it can cause the model to ' tuck under' with the unstalled wing as it rapidly experiences a combination of a sudden and rapid loss of lift and / or a negative angle of attack due to the stalled wing and associated rapidly increased drag...it then 'digs in and bites' with the result that the model will ' flick out' in the opposite direction to the initial stalled wing that easily lifts and flips over because it is in a 'bubble' of turbulent air with no smooth airflow. This is most evident in models with high wing loading. (That is less wing area supporting more mass/ weight.) That is why you get a tip stall in heavier, more aerobatic aircraft with narrower tips and reduced wing section.....the tip has less ability to support weight and maintain flight due to reduced area and a reduced wing section, it needs more airspeed to maintain flight. This can be seriously exacerbated and compounded by a model that is turning. The inboard wing is moving slower relative to the outboard wing and is more readily prone to tip stalling. This catches out hundreds of model pilots on every field in every club across the whole country as they try to turn too sharply or steeply whilst having too slow airspeed. The result is a stalled model in a spiral dive.... panic.......unsure what to do.........waggle everything.......smack!How do you avoid it? SIMPLE.....DON'T FLY TOO SLOWLY OR TRY TO TURN TOO TIGHTLY OR YOU WILL LITERALLY STOP FLYING....wings need smooth airflow to generate a difference in pressure that creates lift to make the wings 'fly.' Different types of wing need different amounts of forward motion through the air to maintain flight. Trainer wings are good at avoiding stalling and are able to fly slowly in slow moving air, ideal characteristics for the learner pilot! Other wings are far less tolerant and won't put up with inexperienced pilots trying to 'fly' them like a trainer wing. It is worth noting though that even the most benign, friendly little trainer wing will eventually run out of steam, give up and stall! It is all about balance once again, maintain flight by somehow developing and maintaining airspeed. The energy for this comes usually by either using a motor or gravity (e.g. in a glider you build airspeed by allowing gravity to take the driving seat for a while!)Back to the spin....... (eventually!)So, to enter a spin when you mean to.....! .....you must allow the model to slow down and lose airspeed to the point where the wing stalls uniformly. ...a word of caution...does this at height. (Obvious statement!)Until you know what you are doing, ALWAYS do this into wind. Don't force the stall by pulling in more and more up elevator at speed with the nose getting higher and higher and the model climbing. Take your time to allow the model to slow down and stall. In a comp, if the model pitches up before the stall you lose mega points. The objective is to keep the model as horizontal as possible, even with bags of up elevator applied and held in. When the model stalls, it should nod and dip its nose from straight and level. It will usually be stopped or almost stopped relative to the ground. This is the exact point, after the stall, , NOT BEFORE, where you smoothly apply full rudder....do this in the direction that is away from yourself so the model spins outwards, not inwards. If the wing is stalled and rudder applied, the model WILL begin to spin. Different models spin in different ways; some more slow and sedate others snappy and more violent. Some models need a little aileron in the direction of the spin to help them get going but not big bucketful’s of aileron or the spin will turn into a spiral dive very quickly. I won't at this point go into how you manage and alter the rate and flatness of the spin. What you need to know next is how to stop the spin and get the model flying again. To resume flight... First of all neutralise all of the controls (you will have full up elevator and full rudder on and holding it as the model is in the spin.) Allow the spin to slow down on its own and to help it bite and begin to fly again, you may need to nudge a slight amount of down elevator as you smoothly apply some throttle. The combination of power from the engine along with gravity acting own the model with its nose down will quickly make the wing begin to fly again. All you need to do then is smoothly pull back on the elevator to stop the descent and 'fly' out. Until you can control the direction of exit by your timing, you need to be prepared for the model to exit in any direction and sort it out from there. Simples! So, go and give it a go, but don't go at it without having thought it out fully first. Think about what you are going to do and what you will do to manage the aeroplane at all times. If you follow these steps you won't have any nasty surprises. ...I am always happy to demonstrate or hook up a buddy lead as back up for your first attempts. ADDENDUM. I left out the following so as not to confuse initial attempts, so do not try the tips below till you are confident with the procedures described above. Full up elevator will keep it spinning and stalled, but when you get more into it, you can control the flatness or steepness of the spin by a combination of the amount of elevator you use combined with the amount of OPPOSITE aileron to keep the spin flat. You can speed it up or slow it down by adding or reducing rudder and to a lesser extent aileron. The other major factor in successful spins is the CG position. A more rearward CG let's models stall and spin more easily. If the CG is a bit too forward, it can be very difficult to induce a proper spin because you can't get it to stall as easily and it is hard to get the nose up..... That is really about the angle of attack of the wings. If you can't increase the angle of attack easily because of the nose dropping due to a forward CG, that again helps the model resist a stall and subsequent spin. I hope this is helpful. Always happy to clarify points etc
© 2020 Glenluce and Galloway Flyers
© 2020 Glenluce and Galloway Flyers