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Posted

I saw that AC91-something-or-rather, and in it there's a diagram of when blade slap occurs. I noticed that in the Robbie, blade slap seems to occur at a shallower decent rate and speed. I got to wonderin' if there might be a diagram of the blade slap profile anywhere for the R-22?

 

Release the hounds!

 

I looked around the Robinson website and didn't see anything. Thought yous guys might know of something.

 

Later

Posted

Nope, never have seen one just fo R-22's. It was me that posted the AC a while back, it's just general range for helicopters and may vary as far as speed and decent angles. Perhaps, if you have time you could experiment and let us in on the results. I just teach my students when they get blade slap to make a small pitch change.

Posted
Nope, never have seen one just fo R-22's. It was me that posted the AC a while back, it's just general range for helicopters and may vary as far as speed and decent angles. Perhaps, if you have time you could experiment and let us in on the results. I just teach my students when they get blade slap to make a small pitch change.

 

I know that sometimes the blade will slap the cabin in a robbie.

Posted

No diagram, but the R-22 POH mentions blade slap under noise abatement 4-13 (2).

"Avoid blade slap. Blade slap usually occurs during shallow high-speed descents, especially during turns. It can be avoided by using slower, steeper descents. With the right door removed, the pilot can easily determine those flight conditions wich produce blade slap and develop piloting technique to eliminate or reduce it."

Posted (edited)

HAI (Helicopter Association International) did some work on this subject.

 

Follow the links I provide for some manufacturer's noise abatement procedures. I think they are an 'unofficial' collection of manufacturer's 'official' statements. UH-1 is quite interesting (being one of the most offensive helos out there).

 

These links should provide what you're looking for, though I don't think they'll have any sort of chart for the R22

 

There is also a quite interesting 'downloadable' video about noise abatement.

 

AC 91-66 Noise Abatement for Helicopters

 

HAI - Noise Abatement Training Program Video

 

MANUFACTURER'S RECOMMENDED Noise Abatement Procedures

 

R22 Recommended Noise Abatement Procedures

 

Hope it helps.

 

Joker

Edited by joker
Posted

I can't remember having this problem at 65 knots or below...usually its when cruising at 75 or 80 and then trying to lose altitude by gently lowering collective....so just lower power and then slow down to 65 when descending and it won't happen....

Posted

I haven't looked it up, but I think it has to do with the advancing blade hitting the vortices of the retreating blade????????

Posted

There was a thread http://helicopterforum.verticalreference.com/helicopterfor...?showtopic=5809

that explained blade slap rather well-I'm still confused. Anyhow, it does make a lot of sense.

 

Later

  • 17 years later...
Posted

It is written in the flight manual of R44 that Blade slap starts below 100kts and in descend, ao to avoid it increase ROD above 1000ft and then reduce speed below 65kts. Now reduce ROD and land.

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