H130T2

[Ugyel]

Why is rotorshaft bent 2 degree forward in H130T2? Your explanation would be highly appreciated 🙏

 

[Hand_Grenade_Pilot]

3 hours ago, Ugyel said:

Why is rotorshaft bent 2 degree forward in H130T2? Your explanation would be highly appreciated 🙏

 

Many helicopters have a forward tilt on the mast to create a more level cruise attitude (more comfortable for crew & passengers). Otherwise you would fly around nose low. 
 

A negative effect of this though is that the helicopter will hover with a nose high attitude.

[adam32]

They are also sometimes tilted sideways to counteract dissymmetry of lift.  

[Disguise Delimit]

Quote

They are also sometimes tilted sideways to counteract dissymmetry of lift.

Actually it is to counter tail rotor drift. Flapping and feathering takes care of lift dissymmetry.

[RisePilot]

13 hours ago, Disguise Delimit said:

Actually it is to counter tail rotor drift. Flapping and feathering takes care of lift dissymmetry.

That is correct.  Damn checkout "Student Poster" schooling "VR Veteran Poster".

Number of posts do not necessarily correlate with correctness of information provided.

[adam32]

16 hours ago, Disguise Delimit said:

Actually it is to counter tail rotor drift. Flapping and feathering takes care of lift dissymmetry.

 

No. Flapping and feathering only takes care of a portion, without tilting the mast you'd be compensating with the cyclic. 

[Hand_Grenade_Pilot]

2 hours ago, adam32 said:

 

No. Flapping and feathering only takes care of a portion, without tilting the mast you'd be compensating with the cyclic. 

You’re partially correct, but it’s not due to dissymmetry of lift. Keep in mind that in a no wind hover, there is no difference in the advancing vs retreating blade.

 Lateral tilt to the mast is to compensate for translating tendency (tail rotor drift). Without that tilt, you would have to apply cyclic to compensate. One example is the S300; no tilt on the mast, but has an extra degree of lateral cyclic to one side.

[Nearly Retired]

Interestingly (or not), the MBB BO-105 has zero forward tilt (or maybe just a degree or two, come to think of it).  But in any event, because of the design of the rotor (no flapping hinges), the mast/fuselage obediently follows the angle of the tip-path plane.  This is quite unlike a LongRanger, say, where the cabin will be flying along in a pretty level attitude while the cyclic is just about on the forward stop and the tip-path plane is tilted very far down-in-front.

At cruise power settings, some 105's would boogie along quite smartly at 120 knots.  At that speed, you would usually see up to *10* degrees of nose-down cabin attitude.  What an uncomfortable POS that thing was to go cross-country in.  I have done some looooong flights in from offshore to New Orleans (like 1:20 enroute) that were just hell on my neck and back - because you're slouched over against the shoulder straps, and with your head tilted up just to see the horizon.  One would hope that they figured out a better way for the BK-117 and EC145.

Edited March 19, 2021 by Nearly Retired
Clarity

[Disguise Delimit]

Quote

No. Flapping and feathering only takes care of a portion, without tilting the mast you'd be compensating with the cyclic. 

Adam, feathering of the main rotor is only going to happen if the cyclic is moved, (or collective raised) so I have covered that eventuality. (The tail rotor is able to feather itself via the Delta 3 hinge)