Vertical Descents

[NiqueNaque]

Sam,Draw a triangle with one side (base) 250mm long and 10 mm high, the hypotenuse (long leg) is the relative air flow, this could be your gyro at zero forward air speed just before it starts to sink.. that is the rotor blade in rotation at the start of sink. Your blades do not stop rotating, if they did stop your scenario would be correct, then you would see a 91.5 degree angle of attack if your blades are pitched at 1.5 and the descent is truly vertical.Don't forget, your gyro is always falling down, the only thing that keeps it up is the flow of air being greater than the rate of falling down. If there is 600 lbs of gyro going up, there must be 600+ lbs of air going down.. otherwise the gyro will sink, not including for inefficiencies.Hope this helps..Nick.

[Tim]

Sam, if the rotors were not rotating, then the angle that the wind hits them would be at 90 degrees. If the gyro was descending at 15 klm/hr and the tips of the blades were doing 15 klm/hr, then the relative wind would be at 45 degrees. The blade tips would more likely be doing something like 500 klm/hr, making the angle of attack very shallow. Plus or minus 50 klm/hr in 500 doesn't make that much difference to the angle of attack.Tim McClure

[asra]

Thanks TimGood example!!!Very happy now, and yes it does make sense.Regards Sam. []

[birdy]

"Its from here on I havent got a clear picture of the spin," As soon as the air starts to enter the rotors/rudder from behind "the pilot", both controls will behave in reverse, coz the pilots still lookn forward. If you had a swivle seat and enough control room in the rotor head, [and big balls], you could fly the gyro backwards much easer coz you, your sences and your brain are facing a head airflow. The rotors don't know its reversed airflow, they don't know which way the machine is faceing.To the rotors, its just airflow, to anything under the rotor bolt, its reversed airflow.So the best thing to do is chop power and forward stick to stop the back slide, especialy in a CTL or LTL machine, coz the thrust is holding the nose/rotorhead at an AOA thats going to keep the disc from leveling out and stopping the horisontal AS.To level any bank/stop any spin, you need to stick out of it. IF your spining backwards, you still need to stick out of it, but coz your lookn the wrong way, It FEELS like your stickn into it.[ if you had your swivle seat and turned to face the air flow, it'd FEEL like you were stickn out of it.]Personaly, I wouldn't do anything with the rudder but hold it centered till the airflow returned to virtical or forward. Depending on the rate of spin and the reversed AS, IF the rudder did actualy bite, I reckon the outcum could be worse than the currant situation. Rudders are for keepn the nose in frount,from behind. If the rudder ends up be'n in frount, it'll have much more aggresive responces to any inputs.Frank said,"Then she started to spin slowly, the blades started to hammer the stops,"The reversed airflow over a slightly offset rudder will initiate the spin.The stick is still back, persumably with the power still on,so the nose is high.The disc angle relative to the horison is very high, and coz the machine is spinning, the huge cyclic damands on the rotors now is make'n the stick shake, not the bar hitn the stops.[that'd cum later]As I said before if the disc was level with the horison in a virtical spin, theres no cyclic input, so no feed back.Now me heads spinn'n again.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[Brian]

Thanks Birdy, for the explanation. Would I be correct in saying that Frank is probably the only person to have ever spun a gyro BACKWARDS ??? and lived to tell the tale !! It must have been a frightning experience to say the least !!Brian

[birdy]

I dout it Brian, I think theres a few others I'v heard of, notable people, that have done it. Some start high enough and have a cool nerve and try different things till sumthn works,[not that they seemed to understand why] others either never had time/alt to work it out or just **** bricks, froze and crashed.I reckon all machines that have been spun in where fly'n backwards,theres no other reason why the pilot couldn't regain control, its just not many people know wot to do if it happens, and reverse inputs wouldn't spring to mind in most normal pilots.I'v often let it 'drift' backwards under power, but when ever it wanted to start yawing or sinking, I'll imeadiatly stick froward. that sinking can actualy be the machine starting to slip off the disc backwards and not virtical. If not arrested quickly, especialy where we fly, you could be the next to spin in, coz we don't usualy have the alt to spare to stop it.It'd be nice to, if Frank got back on here, I'd like to here his side now.Instead of stuff'n up[ only out of ignorance, and it sounds like thats cumn from the 'instructer'] and say'n gyros are dangerous machines.A bad tradesman always blames his tools.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[Brian]

I thnk the **** bricks would feature pretty highly !! I have done plenty of backsling back years ago but nowdays just dont do any more than just let the gyro drift under power and always keep things staight and let the nose drop as soon as the sink starts !I notice Frank is from Whyalla SA is there anyone on the forum who is in that area ???I reckon Frank needs some reassurance that he's not the only one who's stuffed up. There's a list of stuffer upper's a mile long, me included, and more than once !!!Brian

[asra]

Yes I did stuff up, The spin should not have happened but it did, If I had known the correct way to get out of it, It would not have sped up, becouse I would not have powered up after trying to get out of trouble, forward stick did nothing, except I got a lot of shake, right rudder to stop the yaw to the left as Birdy said only made things worse, if anything left rudder would have been better this would have tried to drag the nose right slowing down the spin, you have to have some forward speed for rudder authority, at this point it was to late so I powered up, more air over the rudder sindrome the change in spin rate / speed was astronomical, with no power the spin rate was not frightening, my thoughts were this can't be happening they don't spin, I banked right to turn away from the spin, then left when nothing happened. with the height I had I probably could not have recovered, I know a spin can't be practised, I understand four or five off these types off accidents have occurd over about ten years, so why didn't I know, I have never seen it discussed anywere until now. Don't get the wrong idea I think these machines are the greatest I would fly one again anytime but they can bite. Sorry for the long windedness of reply, I don't seem to have the concise skills off most off you on the forum Regards Frank

[asra]

this is a good thread i wasn't aware of the backwards slip. i'll certainly alter a few flying practices well done for putting your story out there frank it has quite likely saved me from a similar incident. matt

[birdy]

Thanx a million Frank, you got more ball than I thought to cum back on.Do you have FW time???Sounds like you may be get'n confused between the two machines. A gyro spin isn't dangerous, forward, virtical or backward, solong as you know the difference. Much different from a FW with different causes and corrective procedures. Only the effect is the same, sh1tted pants. "so why didn't I know,"Probably coz not many people think of a backward spin, coz its only the rare unlucky ones [ yourself] that ever get caught in one. Your not the first, and wont be the last.I'm just dark on meself for not bring'n up the scinario years ago,Mite av saved you sum pain, sorry.Be'n thought of as a loopy, suncooked desert rat SCG mite av sumthn to do with it, gota be careful how I present my thoughts on this computer thingy.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[asra]

BirdyI've been reading this thread with great interest. Is there a set of simple steps that can be followed to recover from a spin??Ross B

[Brian]

Ross, very simple actually, keep out of one !!Brian

[birdy]

BUT............ if you find your self with a machine thats responding in an opposite way to inputs , then theres every reason to expect your go'n backwards. Accidents happens and everyone could end up in a back slip. All you can do is regain forward AS, by stopping the rotation [opposite control] and full forward stick WITH IDLE POWER only. As soon as the forward AS is regained its back to normal.If your too low, then all you can do is same, but you may bend the mains when you hit the ground.I'v been play'n round with reversed airflow [ I reckon its safe to say that now ] and anyone with more n 500 hours and has a habit of play'n round at low ASs, then its good to practice.This is in no way condoneing the practice of fly'n backwards, coz I don't know nuff bout it.Ignorance is bliss............but only till you realise you were.You can always get the answer you want, if you ask enough experts.

[asra]

Very very glad I have discovered this thread.Still wet behind the ears and practicing vert descents as they had been demoed to me by my instructor. I had experienced no problems and was maintaining heading with a very low indicates AS and high rate of descent. Went out with a friend last week for some air to air with my vid cam. Among the exercises he wished to do was vertical descents. When we got back he complained that his gyro had become uncontrollable and had begun spinning despite his rudder inputs with the high nose position he had been holding but had eventually recovered. I told him that from what I could see he had done a tail slide.A flight or two later I was doing a vertical descent and without too much thought decided I wished to see what a tail slide situation felt like. The gyro after a much higher nose up than I had been doing, did begin to appear to begin sliding back and the nose to suddenly rotate quite quickly to the left despite my rudder inputs to correct. I dislike being out of control and with plenty of height eased the stick forward until recovering some AS and control. I had luckily probably stopped it from going too far, ignorant of how close I was to the envelopeBirdy I do remember you mentioning this on the Rotary Forum some time ago however was not advanced enough to fully understand your warning about flying backwards. In FW aerobatics a tail slide is not a problem and one simply holds the stick firmly to prevent the control surfaces from be slammed against the stops. As I have now learned it can be altogether a more serious business in a gyro. As you say "Ignorance is bliss..."I have emailed my mate with this thread address and a brief precis. Thank you all for the valuable inputs, knowledge and advice.

[Des Garvin]

Resasi, Welcome to our Aussie Gyro forum. Have seen many of your posts on the American forum. Yes this is a forum with lots of good posts. Cheers Des Garvin.