Tractor vs Puller Tail Rotor Orientation
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Tractor vs Puller Tail Rotor Orientation
Just Curious...
Where did the names 'tractor' and 'puller' come from relative to the physical set up of the tail rotor?
I.e., Where did the term 'tractor' originate and exactly what does it mean in the context of the tail rotor orientation? Where did the term 'puller' originate and exactly what does it mean in the context of the tail rotor orientation?
!Correction: I meant tractor/puller vs. pusher. Thank you all for the explanations throughout this thread.
Where did the names 'tractor' and 'puller' come from relative to the physical set up of the tail rotor?
I.e., Where did the term 'tractor' originate and exactly what does it mean in the context of the tail rotor orientation? Where did the term 'puller' originate and exactly what does it mean in the context of the tail rotor orientation?
!Correction: I meant tractor/puller vs. pusher. Thank you all for the explanations throughout this thread.
Last edited by Whimlew; 13th Jun 2018 at 11:46.
This will be a quick start for youl
Bell 205 tail-rotor
That shopping place named for a River has Prouty's Books for sale.
Bell 205 tail-rotor
That shopping place named for a River has Prouty's Books for sale.
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Surely, "tractor" and "puller" mean the same thing? Tractor and pusher, or puller and pusher are opposite.
Tractor/puller means that the tail rotor pulls in relation to the tail boom to counter main rotor torque reaction (e.g. Blackhawk, early Lynx). A pusher is physically fitted on the other side so it pushes the tail boom (e.g. most other helicopters).
Tractor/puller means that the tail rotor pulls in relation to the tail boom to counter main rotor torque reaction (e.g. Blackhawk, early Lynx). A pusher is physically fitted on the other side so it pushes the tail boom (e.g. most other helicopters).
I'd suggest the "tractor"terminology comes from the FW world where "tractor" refers to having the propeller pulling the aircraft, where as the reverse is a "pusher" configuration. Shy has it figured out.
Surely, "tractor" and "puller" mean the same thing? Tractor and pusher, or puller and pusher are opposite.
Tractor: From Latin 'trahere - to drag, to pull', means the T/R pulls on its shaft. Puller: Exactly the same but from English 'to pull'.
I could believe, and this is only a guess, that a tractor tail rotor would use the fin surface as a form of ground effect thereby reducing the power required to hold heading in the hover. A pusher does not have a free airstream for nearly a quarter of its area because the fin obstructs the incoming air.
Just a guess!
Just a guess!
FED, I think you may need to rethink your proposition. Airflow impinging on the fin will want to force the tail in the opposite direction to that desired, hence you need more pedal and more power.
Airflow impinging on the fin will want to force the tail in the opposite direction to that desired
Either the fin obstructs the clean flow into the TR or is pushed against by the TR thrust - its the lesser of two evils.
The other important thing is that the rotation goes up at the front so it has maximum V when it encounters the MR downwash.
The other important thing is that the rotation goes up at the front so it has maximum V when it encounters the MR downwash.
I told you it was a guess!
Pusher versus tractor tail rotor
The pusher position gives the higher level of net thrust with less power
Neither configuration has excessive net thrust excursion at 20 knots, while the pusher has considerably less thrust excursion than the tractor at 35 knots.
Since the tractor must develop more shaft thrust for a given net thrust because of higher fin forces, the tail rotor in the tractor position will stall sooner than a pusher of the same solidity.
The effects of fin-tail rotor separation distance on tail rotor net and shaft thrust are shown in Figure 2-7. This data is for the pusher configuration with a bottom forward rotation and blockage ratio of 0.207. As the separation distance decreases, both the fin force and shaft thrust increase, so that the net thrust output remains approximately constant. The configuration with the lesser s/r, however, will stall at a "lower net thrust level. Thus, for equal stall tail rotors, the greater the fin-tail rotor separation, the less solidity is required.
The pusher position gives the higher level of net thrust with less power
Neither configuration has excessive net thrust excursion at 20 knots, while the pusher has considerably less thrust excursion than the tractor at 35 knots.
Since the tractor must develop more shaft thrust for a given net thrust because of higher fin forces, the tail rotor in the tractor position will stall sooner than a pusher of the same solidity.
The effects of fin-tail rotor separation distance on tail rotor net and shaft thrust are shown in Figure 2-7. This data is for the pusher configuration with a bottom forward rotation and blockage ratio of 0.207. As the separation distance decreases, both the fin force and shaft thrust increase, so that the net thrust output remains approximately constant. The configuration with the lesser s/r, however, will stall at a "lower net thrust level. Thus, for equal stall tail rotors, the greater the fin-tail rotor separation, the less solidity is required.
http://www.dtic.mil/dtic/tr/fulltext/u2/775391.pdf
