helicopter synchronized elevator

[flybik]

Why does helicopter has this elevator?

[Rainboe]

There is a Rotorheads forum where pilots with rapidly nodding heads and a tendency to shout all the time hang out. It's a bit like the bar scene in Star Wars there, but if you dart in, ask this, and get out quickly, you should get away with it.

[Brian Abraham]

Had a laugh at that Rainboe, we nod because we are such agreeable folks. ;)

flybik, on some helicopters the horizontal stab is fixed, while on others such as the Bell 204/205/212/412 series the stab moves with respect to fore and aft cyclic stick motion. The S-76 was initially designed to have a movable stab, but test flying proved it to be not necessary, so it was fixed. Go to page 311 of the following. Hope it answers your question to your satisfaction.

Principles of helicopter aerodynamics - Google Books (http://books.google.com.au/books?id=nMV-TkaX-9cC&pg=PA311&lpg=PA311&dq=helicopter+horizontal+stabiliser&source=bl&ots=CocUk80KbB&sig=82b1ZoxwJyFq3fuUqT4V1HmKpXA&hl=en&ei=0xLlSqfVBJDSsQO_osCuAw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAsQ6AEwADgK#v=onepage&q=&f=false)

With respect to the Blackhawk helicopter, which is probably the most sophisticated, Nick Lappos the test pilot has this to say,

1) Pitch damping - The stabilizer is big enough to provide the pitch damping needed to stabilize the aircraft in high speed cruise, where it acts like any normal horizontal stabilizer.

2) Entry into autos - It has a slow motion angle of attack change capability that allows it to also keep the nose from dropping during entries into descents and autos, where most helicopters need a lot of aft stick to hold things level.

3) Sideslip stability - It also keeps the nose from pitching up or down when sideslips are made at speed, because it detects lateral acceleration and puts some tail up or down to flatten the pitch attitude response.

4) Maneuvering stability - It also helps by detecting the bank angle in a turn and putting the nose down a bit, forcing the pilot to pull back on the stick during high bank angle turns. This gives the aircraft a pleasant aft stick pull to build g's in a turn, so-called positive maneuvering stability.

5) Hover mode - It moves to the hover position (about 40 degrees trailing edge down) when decelerating to a hover, so the rotor downwash on it does not cause the nose to pitch up. This makes the approaches quite pleasant, with the nose staying flat, allowing fast decels and good visibility. At full aft CG, if the stab is not in hover position, the pilot should not make fast quick stops, to avoid running out of forward stick.

[aspire5z]

thanx for the information upside...and i have a question about synchronized elevator too..there are codes on synchronized elevator P,S,R on UH1-H helicopters..ı know the positions of synchronized elevator on flight but ı need what does this words mean?? can anyone help me for this information...