Hi Crab. Thanks again.
Listen. I have only Added a small portion to the entire Pre existing Section.
Please Elaborate on My particular Part.
here it is Again.
"It should be noted that at the onset of RBS. It is the tip of the Blade (Where Relative Airspeed is Higher on that side) that stalls entirely. It has been noted that the tip will start to stall at around the 10 O'clock and be at greatest effect at 9 O'clock and be un-stalled by the 7 O'clock position. It seems almost unlikely that this should happen due to the AoA being less at the tip from built in washout, and also having a Higher Relative Airspeed than the section of blade at the Root, but, as you increase speed with an Airfoil such as commonly used on Helicopters, the AoA at which stall Occurs becomes less.
failure is when the tip has finally stalled. not just the reverse airflow or low lift area near the center on the retreating side"
PS.
1/
reached an environmental operating limit
not true. It has passed
environmental operating limit and it is a failure if it Fails to produce enough lift to sustain level flight.
2/
BGring - a vital point you have left out is that the root of the retreating blade is not producing useful lift at all - it is in an area of reverse flow. Therefore the remaining area of the blade on the retreating stall has to operate at higher angles of attack to equalize the lift across the rotor disc.
this is in the appropriate section call Dissymmetry of lift. (Not created by me By the way, but I do wish to edit that section to. (see paragraph 5 of
Analysis "http://en.wikipedia.org/wiki/Dissymmetry_of_lift", this paragraph is incomplete and misleading to me.
3/
You imply that the tip stalls first
I was not Implying that. In fact I said that once the tip has stalled, it is Failure. this should imply that there are no other signs besides the
effects of Complete RB
S.
4/
The stall angle of the aerofoil may well change at higher speeds but we are talking about the low speed side of the disc so that argument is inapplicable.
not true. Do the math at Vne. now look at your stall/AoA-V chart and revise. all blades have a stall angel. The argument is that if the pilot pushes the craft, IE forward cyclic to go past Vne, Then they are going to get an AoA sufficient to cause a Stall AoA on the retreating side. (Please don't mention why they blade reaches its stall angel, it is a variable. Crab, Ever heard of Flaping to Equality ? not a Pilot myself. but I have heard of it. hehe). The last part to stall will be the tip. and it will be tip to partially in and back to tip as the blade passes 10 to 9 to 7o'clock respectivly.
Thanks again Crab.
could I get you to re enlist me on to your team for a moment and review my post . Please take note to what I said I added. and what I will be willing to change.
PSS If you think there are other parts that need to be changed or added (That is parts i have not posted here but can be found at the link i provided here) you can do so yourself(I would be interested in you additions or edits). But for now. I am not changing anything that was already there, Not without solid feedback and Reputable Text reference and Total Edit being submited for Scrutiny, (Even then, Changing existint text is not what I feel comfortable with)As it is, I feel that the small addition that I did has not extracted from what was already there.
The language used in the article is not 'explanation friendly' and uses some inappropriate words and phrases more likely to be found in an academic or engineering book than a flight manual.
I found that if I read some sections fast I could get confused as to the meaning. (Due to Check and Self check of what was being conveyed) however the second time I read. I was able to get a better fly of the text and understand what was being conveyed. Some points I
disagree, and others, Like you you mentiond, I feel have been left out.
The quoted source is an FAA Basic Helicopter Handbook but I would be surprised if it says exactly (or even close to) what has been put in the RBS article.
Here is my addition.
"It should be noted that at the onset of RBS. It is the tip of the Blade (Where Relative Airspeed is Higher on that side) that stalls entirely. It has been noted that the tip will start to stall at around the 10 O'clock and be at greatest effect at 9 O'clock and be un-stalled by the 7 O'clock position. It seems almost unlikely that this should happen due to the AoA being less at the tip from built in washout, and also having a Higher Relative Airspeed than the section of blade at the Root, but, as you increase speed with an Airfoil such as commonly used on Helicopters, the AoA at which stall Occurs becomes less.
failure is when Finaly the tip has stalled, not just Prelude and contributing factors to a Requirement to the Greater AoA on Retreating side such as the reverse airflow areas or low lift/stall area near the Root of the Blade on the retreating side, Please revise "http://en.wikipedia.org/wiki/Dissymmetry_of_lift" as it Preludes the final Onset of Tip stall"
less than .5% of people who have seen this Thread have Bothered to post. (Don't expect more than 2%, but even then that leaves room for 3 more to jump in and add to it) thanks again Crab.
