All Things Aviation Related

[svandamme]

Originally Posted by flipper35

The Vipers found out that a 6 G turn at support speeds is a higher rate of turn than a 9 G turn at fighter jet speeds.

I'm sure those Viper pilots won't make that mistake again.
There's really no excuse for them to think that they could out Rate a slower A10 when they themselves are going fast.
hell anybody in DCS already knows not to try turning with an A10 and simply extend, get high, into the sun, and then come down to pick the bones clean on that A10..
an A10 can't follow and cannot defend against that. Sitting duck.
So if amateur civvies know it, a half decent actual Viper pilot should too.

Fighter Pilot Rule, above all don't look bad
Getting shot down by an A10 is pretty bad looking

[svandamme]

one more for Seahawk

[svandamme]

good explanation.. learn something every day




If I understand it correctly, this Low G and Mast bumping is the Helicopter equivalent of Aerodynamic Stall and departing the plane in a fixed wing ? With one major difference, you can recover after departing a fixed wing, but mast bumping is kinda way worse and usually more final.

Does that at all make sense?

[Fast Freddy 944]

My old man flew a Cobra in Nam, flew offshore heli's to a floating platform, did powerline inspection missions, and also had a fixed wing license for mulit engine, jet and prop jobs. Choppers ain't airplanes, ya gots to have guts to fly one.

[Fast Freddy 944]

Thunder-screech!

[Seahawk]

Originally Posted by svandamme

If I understand it correctly, this Low G and Mast bumping is the Helicopter equivalent of Aerodynamic Stall and departing the plane in a fixed wing ? With one major difference, you can recover after departing a fixed wing, but mast bumping is kinda way worse and usually more final.

Does that at all make sense?

Main rotor head design vary greatly, as does blade design. In Fast Freddy's picture (very cool, btw) you can esy see that the Cobra shared the "teetering main rotor" design with the Huey.

That design was susceptible to mast bumping.

The H-60 main rotor head design is not susceptible at all to mast bumping.

There are also rotor head designs, like on the Lynx, that allow for aerobatics.

So, it depends. There are rotor systems that are more like to have "retreating blade stall" characteristics than other designs. It is all a trade-off.

Oh, Harry Reasoner can kiss my grits

[KNS]

Originally Posted by svandamme

If I understand it correctly, this Low G and Mast bumping is the Helicopter equivalent of Aerodynamic Stall and departing the plane in a fixed wing ? With one major difference, you can recover after departing a fixed wing, but mast bumping is kinda way worse and usually more final.

Does that at all make sense?

That statement does not make sense, not sure what you're trying to say.

Mast bumping and (rotor) stall is unlike a stall in a fixed wing, rotor stall is not recoverable. Stall in a fixed wing aircraft is almost always recoverable.

Low G along with mast bumping are completely separate issues from rotor stall. Mast bumping can result from low G. The Robinson in the video either had a structural failure, or, more likely suffered from a low G condition. When a two bladed, underslung rotor system becomes unloaded (in a low G situation or possible heavy turbulence), the rotor system may not respond to control system (cyclic) input in the way the pilot would expect.

An aft cyclic input may result in the blades contacting the tail boom. Or, with the main rotor unloaded, the rotor bump stops can make contact with the mast causing separation of the main rotor system (not what happened in the video).

It is also possible they were practicing low rotor RPM recovery and let it go too far (unlikely but possible). The stalled rotor then may have contacted the tail boom. I doubt this was the case.

Of my flying time, about 3000 hours of it is in two bladed Bell products (206L) with some Robinson time as well. This stuff is fundamental. All this is drilled into new Robinson instructors and I'd heard there was an instructor and student on board.

[svandamme]

well on fixed wing, aerodynamic stall, by definition means 0 g on fixed wing.
Aerodynamic stall means no lifties.
low G on helicopter.. I would think means .. .no lifties, which then makes the blades come down to do the mast bumping.. (and contact the boom/tail assembly)

So all i'm comparing, is the flight regime, and that both types of air craft have their own problem that arises if you do the wrong things at that state..

Obviously they have completely different outcomes when it goes wrong after that


I already suggested earlier, in the picture i screenshotted from the video , that I think it's maint or airplaine failure.. not the rotor that chopped off the tail .. the tail came out in a way to clean section

[Seahawk]

Originally Posted by svandamme

well on fixed wing, aerodynamic stall, by definition means 0 g on fixed wing.
Aerodynamic stall means no lifties.
low G on helicopter.. I would think mean .. .no lifties

So all i'm comparing, is the flight regime, and that both types of air craft have their own problem that arises if you do the wrong things at that state.

I get it.

"Retreating blade stall" means that the retreating main rotor blade is indeed stalling in the classic sense. It generally happens at high speed (relative to a helicopter) and the retreating MRB, which is aero designed just like a fixed wing, stalls. It can be disastrous from a control perspective: part of the main rotor is producing lift, another part is in stall. The helo will generally depart controlled flight.

For classic "no lifties" look up "vortex ring state" and "power settling" (sometimes called settling with power)...Everything is working except the lifties are gone

[svandamme]

yeah but that's just the single rotorblade
I'm talking about the entire aircraft.. which well on a fixed wing is pretty much the wing since the wing is fixed.(ignoring f35 or harriers, those can maintain flight despite stalled wing)

The mast bumping would happen if the helicopter is in the same low G state as a fixed wing

And while the fixed wing, typically will self recover.. it can depart if pilot does the wrong thing.

in rotorcraft, obviously the darn thing won't self recover because it really doesn't wanna fly to begin with.. So pilot has to do something right if he wants to come home that day.
But if he does something wrong, he'll end up with mast bumping (bad bad) where the fixed wing would most likely just spin (bad but ok if altitude is there)

no?

So basically fixed wing vs helictoper
Helicopter basic state is already unglued to begin with, and problem state means critical in seconds.. where fixed wing only starts becoming unglued at much more evolved problem state and critical state is waaaay longer process to arrive

[Seahawk]

Originally Posted by svandamme

yeah but that's just the single rotorblade
I'm talking about the entire aircraft.. which well on a fixed wing is pretty much the wing since the wing is fixed.(ignoring f35 or harriers, those can maintain flight despite stalled wing)

The mast bumping would happen if the helicopter is in the same low G state as a fixed wing

Think of the entire main rotor as a series of wings. Helicopter blades come in an astounding variety of shapes, sizes, rigidity, aero loading, etc.

If one blade stalls, the "wing" is in stall just like a fixed wing aircraft can, depending on the flight regime, have part of the wing in stall while other parts are still providing lift.

Mast bumping is generally a combination of low G and negative G control inputs. Think of it this way: a helicopter flying straight and level at 40kys is essentially in low G flight. There are control inputs, say an aggressive "push over" that would unload the head from low G to negative G and cause the rotor to "bump" the mast.

The only helicopter I have flown as a PIC that was susceptible to mast bump was is the Bell Jet Ranger in flight school. A lot of our training was in how to avoid negative G's on the rotor head.

I am doing this from memory from a long time ago and I may be misremembering

[svandamme]

yeah, the more i learn about it, the more I think i'll stick to fixed wing when i win the lottery.. cause yall rotorheads is nuts !

[Seahawk]

Originally Posted by svandamme

yeah, the more i learn about it, the more I think i'll stick to fixed wing when i win the lottery.. cause yall rotorheads is nuts !

Honestly, save up for a flight. It is fun!

Second cruise, good day to fly off off small boats at sea:

[svandamme]

Was saved up for a flight in a P51 that used to be Robin Old's
Was due to fly but weekend before my turn, it had metal in the oil and engine was buggered up..

That was summer of 2020 and it's still not back to flight status
and my money is by now blown on other things. and changing jobs and cost of living up
and blablabla..

so I am waiting Scat to return to flight



oh yeah, it's dual control, so if they let me do even just a basic maneuver (it's in the package) I'll then have the right to say I have flown a P51 (barely , but facts are fact innit)

[Seahawk]

Originally Posted by svandamme

oh yeah, it's dual control, so if they let me do even just a basic maneuver (it's in the package) I'll then have the right to say I have flown a P51 (barely , but facts are fact innit)

I like it!

One last pic. The Marine on the left was one of my roommates and we took this picture at his "winging" ceremony. Other roommate in the middle, me on the right in the picture.

The Marine flew Huey's out of Pendleton, Jeff and I flew out of North Island, San Diego and we may have had some fun.

1984 NAS Whiting Field.

[Racerbvd]

[svandamme]

Not much of those left, I think Porsche tried to buy em all back to be done with the liability of supporting those

[Fast Freddy 944]

Thunder screech.

[911boost]

Very cool picture Paul

My dad was based in San Diego in ‘84, he was on the USS Fanning 1076 at that time.

[svandamme]

Originally Posted by Fast Freddy 944

Thunder screech.

That must have been a terrible ordeal for the pilot flying that for any length of time.