Here's another video.

This is a stock version, with rigid rotors.

http://www.flixxy.com/helicopter-aerobatic-flight.htm

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KLK, MCSE

1990 500SL

I was always taught to respect my elders.
I don't have to respect too many people anymore.

The gyroscopic forces developed when changing attitude of the main rotor are huge..........I'm amazed that such a machine can take that abuse and live to tell about it.

..........good flying skills, for sure..........

when i was working for general builders, about 30 years ago, we did a lot of work for mcdonald's restaurants. one day some of the big wigs flew into our place in a helio. it was a big thing that sat maybe six or so. while they were meeing with our big wigs the pilot came in and asked if anyone wanted a ride. i was the only taker.

i guess he figured i wouldn't complain being a young testosterone filled man.

first impression after only riding in fixed wing craft was as we rose up how many power lines there were to potentially hit. being right next door to the alcoa plant some of them were pretty big.

but we got up into the air just fine.

and we flew out to open country. and i was treated to some maneuvers that i had never imagined a heliocopter could do. he laid it over and banked it into a very tight turn a couple of times with me looking out the side and seeing that we were perpindicular to the ground. and then he put it about thirty feet above the interstate and flew pretty fast just there, having to climb up to go over the bridges.

i was impressed. i thought about asking for mercy but i figured he wouldn't kill himself so i just held on and enjoyed the ride.

after the intense stuff was over and we were flying back to the office i asked him some questions and found he was a vietnam vet flyer. i said ..."i guess any flying with nobody shooting at you must seem pretty safe". he smiled and said "yeah."

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

yeah, now that i understand the operaiton (vaguely) of the rotor hub and understand what happens if that fails on a copter, i tend to stick with fixed wing craft which (theoretically any way) can glide down if a problem occurrs.

i actually feel safest in a small plane with one or two engines in the hands of an experienced pilot.

i don't get airsick or seasick.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Ever spin a bicycle wheel as a kid while holding onto a shaft that sticks out of the hub?

You have a very difficult time moving the shaft 90 degrees due to the gyroscopic force from the wheel.

Now, multiply the force by 1,000,000 and you'll see what a helicopter main rotor shaft does to it's bearings every time the pilot does some of those 90 degree maneuvers.

so i should have been scared?

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Another fine tribute to modern rotor-wing technologies. Design. Materials. Control systems... The list goes on. ...

Also a good example for the other thread where we mentioned wars/military making such a positive contribution to the civilian aerospace industry.

Keep the forward airspeed down, and have a ball !!

Thanks for the show.


BTW - Tom - “asking for mercy” ???
You should have asked to put your hands on the controls. He probably would have let you try a few (simple) things. You’da loved that !!

Scared? Hell no.

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1980 300D - Veggie Burner !

What he did with you on the flight is nothing compared to the video. I'm sure he never approached the limits of the machine. Now, the video is a completely different story. I don't think that helicopter has unlimited roll rates.........the pilot must "slowly" roll the machine to avoid overstressing the main rotor. It's far more dangerous than it looks.

Would you agree that the helicopter in the video does not have unlimited roll rate capability and that the pilot must be extremely careful not to exceed specific roll rates and air speeds to keep the main rotor forces within limits?

It seems to me that it's far more difficult and dangerous than it appears.

I’m sure you’ve probably seen/done this, but:

Next time you do that. Go down to the local hardware/home improvement store and pick up a turntable bearing plate for a “lazy Susan”. Stand on it while you’re doing as you described. Lots-o-fun. My kids got that lesson early on. Made explaining the helo-basics a lot easier.

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1980 300D - Veggie Burner !

Yes, I would. As far as the pilot having to maintain specific envelope parameters to keep forces in check. But not so much in that the aircraft would hit some limit and come apart. More that the aircraft would experience forces that would cause it to enter an attitude that the pilot was not seeking. Making recovery an issue. And a big issue at that.

More difficult and dangerous than it looks. Not really. Not for/to an experienced pilot (who often does that sort of flying), anyway. I know that driving in downtown NYC traffic would be very difficult (and dangerous) for me. But for you, it’s a daily walk in the park.

There’s not an aircraft made that has an unlimited roll rate. Roll rate is the rate at which the aircraft is actually able (capable) to roll. Not a structural limit that the pilot is allowed to safely roll the aircraft. Pilots on the other hand, do have roll rate limits. But that, we’ll touch on later perhaps. Some aircraft do have what can be referred to as an operational roll rate limit. A rate at which the aircraft is rolling too fast to be of any operational use. This usually occurs on about the third or so roll in a series with full deflection held. And the “limit” is based on what the pilot can comprehend and do anything with at that rate.

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1980 300D - Veggie Burner !

Interesting. I would have thought the aircraft is roll rate (and pitch rate) limited. The faster the roll or pitch rate, the higher the forces.

Clearly, the pilot must have a limit due to blackout issues and loss of spatial orientiation.

Speaking of that I was always amazed at how the military pilots could maneuver at night if the doors were shut and the pilots did not make any fast moves down seemed like up up-down left-right...a true a cookie tosser for a FNG.

They are limited. An aircraft (by design) can only roll so fast. They are not designed, built and sold however, with a factory determined and certified roll rate that the pilot should never exceed (As if to say: It will roll faster, but don't try it, or the thing will break.). Like V-Speeds: Vne (never exceed velocity) At the same time - I guess an idiot pilot can go up and jerk the snot out of most any aircraft until something fails. But lets not go there.

Some (mostly military) aircraft can be a little different. Take the F-16 for example. It has a continuous roll rate of around 325deg./sec. It will roll to 90degs at a much faster rate however. After about 270deg., the flight control system will slow and hold it’s rate to around 325, no matter what control input the pilot holds. This isn’t do to the possibility of the aircrafts structure failing however. This is what some aircraft have that I referred to as an operational roll rate limit. Ie. It can roll faster. But what’s the point?

So - An F-16 has a roll rate near 325 deg./sec. A T-38 is around 355 deg./sec. (well into the ZING! category) But (hold onto something), our EA-300L has a roll rate of 400deg./sec.
But (you can let go now) get this - The F-16 can get to 90 degrees much quicker than the 300L can. To 180 as well. But, after about 270 degrees..... Let’s just say the 300L provides a wilder ride in the full deflect spin category. Four turns is about anybody’s limit. DJ can/will go for more and be able to snap it off at darn near any given bank angle you request. But then, we often question if she’s actually human or not.
(There‘s quite a few more like her out there, so be advised - we aren‘t alone.)

Roll rates are also affected by many contributing factors. Such as air speed, AOA (angle of attack. wing position to airflow) and AOE (angle of entry. Aircraft (nose) position related to the ground). And whether you’re actually trying to roll around the central axis of the aircraft (what we’ve been talking about here) or do a barrel roll (which still has all the ties to the aircraft‘s roll rate). You’ll notice in the video that prior to a roll, the pilot slows and brings the nose up quite a bit (AOE). This is all because of the aircrafts set/determined/known roll rate. The slower the roll rate, the higher the nose needs to be upon entry. And that, is all because of the attitude that you want to be in following the completed roll. I would venture to say that any aircraft that you have seen (Wright Flyers aside), can be barrel rolled. It’s all about keeping the forces in check. A Cessna 172 can safely roll. A Boeing 757 can safely roll. (We’re talking flight physics here. Not effects on instruments, etc.) They both have roll rates. The barrel roll is positive forces all the way around. The aircraft doesn’t even “know” that it’s upside down. (In fact, DJ insists her students be able to barrel roll the 300L with her hardly detecting it if her eyes are closed. Yes - It‘s a very slow roll.)
The lower the roll rate the higher the nose upon entry to the roll. This enables the aircraft to fly through the roll to a point that is within structural limits and an acceptable attitude when it reaches (often falls to) the end of the roll.
As far as helicopters go, things can be a bit more critical than fixed wings. If you have too low an entry angle (or air speed) in a 172/757, you’ll fall on your back (if you’re not lucky enough to split-s) and put some nasty loads on the wings. With enough forward speed, altitude, and quick reflexes to pull the nose toward the ground to relieve the wing stresses, you may be able to aileron roll it out before something snaps. In a helicopter, the thing you’re trying to prevent from snapping is also the thing you’re trying to put more forces into to help you reach an acceptable attitude before it snaps.

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1980 300D - Veggie Burner !

Funny you mention that. Most think that the aircraft has to be pulling some pretty high G forces to black out a pilot. Usually negative (most common), as pulling the blood out of your head is what does it the quickest. But smashing blood into your head has it’s ill effects as well. And this can be achieved without prolonged G forces. Your head is above the central axis of the aircraft. The 300L can continuously spin so fast that the centrifugal force will pack your head with blood. And the rest of anywhere above your belly-button with everything else.

Yep - That spatial orientation gets them every time.

YEEEE HAAAA !! Gotta love fly’n !!

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1980 300D - Veggie Burner !