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Blades popping off after sneezing on them


jcdenton
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Hello nerds,

 

Can one of you please expound on the exact conditions under which the blades will pop off? This happens quite a lot and I am often unsure of the cause. Converting energy (e.g. by pitching back in forward flight) audibly loads the blades, but does not cause them to pop off. Meanwhile my totally perfect flawless landing (pictured) caused the blades to pop off even though there is no evidence that they collided with the tail boom or whatever, assuming that is even possible. My daddy flew F-45s in Vietnam and he said the blades did not just pop off together like that. The blades, still attached to each other, float away like a child's toy while the fuselage crashes and burns. This is extremely frustrating because the virtual crewmembers are in the fuselage. I'm afraid I'll have to request a slider be added in the settings menu to adjust the heat treatment quality control on the alloy shaft, so that the blade can snap off in highly exacting and precise computer-aided tomography. After the first blade snaps off, the assembly should vibrate violently until the second blade snaps off flying 1000 mph and sticking into the ground, because that's what my daddy says happens. The main shaft also has to be bent at the exact angle due to the modulus of combustion or whatever. In the highly unlikely event that my perfect flying is to blame, please communicate how to stop the blades from failing using MS paint diagrams. Thanks for reading. Also why do buildings catch on fire when I lightly graze them with the skids? Buildings don't have feelings.

 

hnFazOU.jpg

oo9R2

http://imgur.com/a/oo9R2

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Here's an interesting army training video about mast-bumping:

 

In short: if the rotor-disk is unloaded the disk can tilt more than its physical limits thus severing the main rotor mast.

Most common (but not exclusive) cause is a "low-g pushover" maneuver, for instance if youre in a climb, then lower collective while pushing cyclic forward. But the video above will give you a pretty good idea what mast bumping is and how to avoid it.

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Hi jcdenton,

The first thing I would tell you is check your axis assignments. DCS has a habit automatically assigning inputs to any peripherals attached to your computer; even thought you checked before. Make sure that only the one you use as a throttle is assigned.

Second, collective inputs should be made slow and smooth. Movements too aggressive can cause this (not the only cause but one of them).

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Imagine Gunther Herman voice here:

 

Agent Denton. When the blades pop off your chopper, the landing is not flawless! Now go back and practice until your blades don't pop off any more. Any more destruction of valuable UNATCO property will get you a reprimand from director Manderley!

 

[End of Deus Ex references; SCNR :D]

 

We could write and paint for ages in order to tell and show you how to land the DCS UH-1H. Or you could just record a quick track of what happens, upload it here, and then we can actually tell you what we think went wrong and how to correct it. Saves everyone a lot of time. :thumbup:

 

PS, don't sneeze on the blades. That's not very hygienic. ;)

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Here's an interesting army training video about mast-bumping:

 

Thanks for posting this. It appears that the rotor assembly doesn't like it when the force vector isn't perpendicular. Once I started noticing low-g states the incident rate dropped dramatically. Also, I was using a lot more cyclic input than necessary.

 

So theoretically if a student pilot gets into a R44, increases rotor rpm, and moves the control stick to the stop, will the same thing happen? Will you feel vibrations or know when the parts are colliding? I guess it's about as bad as applying down elevator when taxiing a conventional gear fixed wing aircraft...


Edited by jcdenton
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Hello nerds,

 

Can one of you please expound on the exact conditions under which the blades will pop off?

 

 

Any number of reasons when I first started it was generally being too ham fisted with the collective (usually only the collective) think of DCS more as a SIM not a game. :thumbup:

 

 

 

Also why do buildings catch on fire when I lightly graze them with the skids? Buildings don't have feelings.

 

That sounds a lot harder than a light graze of the skids, happens on buildings and bridges and such when you hit them too hard. I used to get that but practice practice and more practice, the Huey can land very gently so as not to let the smoke out.

 

Wait till you find the cranky buildings that throw you off em,.. :music_whistling:

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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  • 3 weeks later...
  • 2 weeks later...
So theoretically if a student pilot gets into a R44, increases rotor rpm, and moves the control stick to the stop, will the same thing happen? Will you feel vibrations or know when the parts are colliding? I guess it's about as bad as applying down elevator when taxiing a conventional gear fixed wing aircraft...

 

Mast bumping is generally associated with any RW aircraft that does not have a rigid rotor system. The Huey is one such example and more notorious for mast bumping, but the R44 is also a "semi-rigid" design meaning it has flapping built into the hub and so therefore, it too can experience this issue.

 

Many of the more modern aircraft will handle flapping differently and may have a more rigid rotor system that is less prone to mast bumping or similar effect. So the bottom line is that no matter the model, all RW aircraft should be flown to avoid "unloaded" rotor disc flight. Always keep a positive G loading on the aircraft and avoid abrupt control movements and you should be fine.

 

Highspeed

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Yes, thanks AlphaOneSix. That makes sense. It's a matter of the hub being able to come in contact with the mast at high deflection angles. With fully articulated, this can't happen as the flapping happens at the blade hinge point and not by moving the hub itself. This is actually what I was referring to when I said "more rigid" designs but couldn't recall the proper term for it so thanks for the clarification.

 

Highspeed

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