To Eden
Hope you got the email, so that everyone can understand(hopefully I might even understand it myself one day)I am posting my thoughts about the NOTAR here(I dont wish to divert the thread,but I dont think it warrants its own one and is kind of related)
The NOTAR system basically works from air pressure created by a fan at the front of the Tail Boom (Tube)This fan is driven by the turbine in the same way as any TR drive.
The fan is very similar to A FENESTRON in looks but with very short blades (about 60mm in length)The fans pitch is increased and decreased/coupled to the pedal inputs(Strangely enough it increases pitch in both directions) and consequently greater pedal input creates greater pressure in the tube.
at the end of the Tail Boom there is (for want of abetter expression) a rotating dustbin which allows the air pressure in the tube (from memory its around 3psi)to be directed for pedal turns in the hover.
There are also two long slots on one side of the boom (and a diffuser on the otherside)which are configured so that air continually comes out of the slots in a downward direction,so that in the hover the downwash from the Main Rotor Flows over the boom and using the principal of there then being a low pressure one side and highpressure the otherside of the boom (Coanda effect I think)This also creates some of the anti torque in the hover (think its 20 %)
Obviously as you move into forward flight the downwash is not flowing over the boom and the air pressure from the bucket is less effective so the 2 Rear verticals are also connected to the pedals (either by cable or in some configurations by linear motor)so in forward flight you have rudders!
And there you have it simple,a bit like me.
Flying it is very similar to a normal TR but the following are what I find to be the differences.
1.Firstly in the hover the pedals need a lot of movement,but in forward flight they are VERY sensitive (unless AC is YSAS equipped)
2.When its windy the pedal movements are quite big in the hover,but still plenty of power.
3.As the tail goes thru the wind there is no snap like a TR, everything seems far smoother
4.When you are coming into the hover from forward flight you actully have to apply more right pedal (as the downwash sticks to the boom)before a big boot of left.
5.In flight the vibrations/resonance of a tailrotor is non existant so its very smooth
With these in mind its just like any helicopter it has quirks,but I guess you learn to live with them and being a low hour pilot and having spent 50/50 in TRs and Notars I havent built up any great aversion to them. But when you land in a forest or in fact anywhere (even an airfield) not having to worry about people walking into(airfields) or things hitting the tail rotor does allow some comfort(I know the LZ is always checked and scrutinized but this thread would be here if accidents didnt sometimes happen,and its amazing how a running TR looks like a bicycle wheel to our canine friends who shouldnt be off alead but sometimes appear from nowhere.)
Autos:
These feel very similar to a normal TR.
TR Failures:
Again very similar but if the fan fails in forward flight you can actually land (at 40 knots ) using the rudders, having tried this to the concrete and to the grass it is a wild ride! (ever tried slowing down on skids on concrete with no TR authority form 40 Knots?and yes using the throttle/finger pointing method helps but you have to be quick to make it stay on the runway and not go pirouetting onto the grass)
As said before stuck pedals can be alot worse than normal TR because of the effect of the rear verticals
Problems:
Havent really found any yet, some people say that in heavy rain the fan has problems but having flown in heavy(maybe not american heavy)rain I have not found any problems.
Just make sure no one has thrown a bag of bolts in the fan intake on the walk round (can you believe this has actually happened to one, and it still flew,not as quietly though and there were a few red faces)
This is how I understand it,and have tried to make it as understandable as possible with goinginto the real tech side of it (that would tax my brain too much)and Im sure other NOTAR pilots will hopefully have more to add,with differing opinions I should think
Unfortunately some LOVE it some HATE it,me I just enjoy flying it.
Regards
hoverbover