Calling all Heli grads or current students...

[Eric Sharp]

Just a quick hello to all from a new user.....

 

Have a training question to ask.......at what angle will dynamic rollover occur?

[Sparker]

I don't think its that simple.

 

There are too many factors, it usually caused by a skid or wheel hanging up on something, and the "angle" would be determined when the cyclic is maxed out opposing the roll, and I guarantee it can vary by machine, ground speed, pilot reaction time, wind, slope of the ground, CG of the machine, how much coffee the PIC drank that morning, if the Packers are winning, and the brightness of the sun.

[K-38]

If you need a number it's 15 degrees in the R22. But as the above comment stated it's not that simple.

[slick1537]

You forgot the location of the planets in their orbit, and also the location of the tides is also a pretty important factor.

[gmsemel]

It depends on the condition of the landing area, how much slope or no slope at all, how wet muddy or snow and ice. Or are you on tundra. I do a power at hover check before I set down and note the power I need to hover. That way I have a reference for when I want to hover and well I get near that number I exersise a lot of care. You get to that number and you are not in a hover then maybe things changed, weight, temp wind etc or you are stuck to the ground and If you keep going on skid will get unstuck first and over on your side and the machine will beat itself to death. You get the blame and the note on your record and you get to explain it for the next 20 or so years.

[Bradley P]

I have to agree with Sparker's answer. It just isn't that simple.

[robertson]

Brad,

 

K 38 is correct. If you just need a number it is 15 Degrees - but there are too many factors.

[Autorotator]

If this is a question you will have for your practical test (private or commercial), the examiner will most likely be looking for an answer of 15 degrees (R22). If it is for you CFI practical, the examiner may want to know how some factors may contribute to dynamic rollover. You may also add that static rollover will happen at (if my memory serves me correctly) 42 degrees.

[HelliBoy]

I was taught that it could be as little as 5 degrees in a Schwiezer. The angle will decrease will the magnitude of the rolling moment. The Critical Rolling Angle is reached when the velocity of the roll prohibits corrective action so to find the true C.R.A. you'd have to have a dynamic roll with little or no rolling moment and I'm not sure thats something you'd want to test. It would be so slow and deliberate that I dont think it could really ever happen the real world...that being said it probably has. The true C.R.A. would be the same for dynamic and static rollover. It has to be pretty close to the angle between the disc and the mast with full lateral cyclic deflection. Dont have my POH handy but its between 10 and 15 degrees in a schwiezer I think.

[Helihead]

If this is a question you will have for your practical test (private or commercial), the examiner will most likely be looking for an answer of 15 degrees (R22). If it is for you CFI practical, the examiner may want to know how some factors may contribute to dynamic rollover. You may also add that static rollover will happen at (if my memory serves me correctly) 42 degrees.

 

 

what is the difference between static roll over and dynamic rollover??

[Wally]

Just a quick hello to all from a new user.....

 

Have a training question to ask.......at what angle will dynamic rollover occur?

 

Upwind and upslope? Downwind and downslope? Level, no wind? How's your auto-rotational rig? Where's your lateral CG- you do know how to figure that, don't you? There's more than a few variables that affect the "critical" angle. The important thing is to do all your lifts vertically, as slowly as possible until clear, and recognize the situation before it becomes an emergency. Skids being stuck/bound/restricted is not uncommon.

[K-38]

what is the difference between static roll over and dynamic rollover??

This is the simplest way I can think of to explain it, however I'm sure the more experienced pilots can provided a better explanation.

Static Rollover occurs when the main rotor is not producing any thrust. If you were to go out to your R22 right now and lift one skid up off the ground at a certain point (somewhere around 42 degrees) the aircraft would tip over on it's side. For Static Rollover to occur you need two things: 1 a pivot point, 2 the power-off critical angel must be reached (approximately 42 degrees).

Dynamic Rollover occurs when the main rotor is producing thrust. If you were to go out to the same R22 this time with the engine running, and the main rotor producing thrust, and lift one skid up off the ground you would not have to lift the skid as far off the ground to tip the helicopter over on it's side. That is because at 15 degrees (the critical angle in R22) the thrust of the main rotor combined with the 15 degrees you have lifted the skid into the air would push the helicopter over on it's side. For Dynamic Rollover to occur you need three things: 1 a pivot point, 2 the critical angle of 15 degrees must be reached, 3 the main rotor must be producing thrust.

[Autorotator]

what is the difference between static roll over and dynamic rollover??

 

1 a pivot point, 2 the critical angle of 15 degrees must be reached, 3 the main rotor must be producing thrust.

 

1. Pivot point other that C.G.

2. Rolling moment

3. Thrust greater than weight