Questions tagged [contra-rotating]
Use for contra-rotating propellers and coaxial rotors.
7
questions
0
votes
0
answers
160
views
What is the meaning of "Contra-Rotating Propeller Increases Efficiency"? How is it calculated?
This picture is taken from here.
In that video is mentioned that contra-rotating propeller increases efficiency up to 6-16%. Regardless of the number that could be vary from one airplane to another, ...
- 4,411
1
vote
0
answers
47
views
What are the expected vibration frequencies in a co-axial rotor system with contra-rotating propellers?
I am trying to understand the frequency spectrum of a co-axial rotor system. Form now i have a RC helicopter with two sets of three gear systems arranged in parallel, The number of teeth are 7,23,27) ...
- 11
6
votes
2
answers
168
views
Do the blades of the rear disk have different geometry to the blades of the front disk on a contra-rotating assembly?
If my understanding is correct, the air flow is accelerated by the front propeller toward the rear propeller in a contra-rotating prop assembly. Therefore, the rear disk would be receiving air at ...
16
votes
2
answers
4k
views
Why don't NK-12 powered contra-rotating propellers turn in equal rpm?
The Kuznetsov NK-12 is a Soviet turboprop engine of the 1950s, designed by the Kuznetsov design bureau. The NK-12 drives two large four-bladed contra-rotating propellers, 5.6 m (18 ft) diameter (NK-...
- 27.2k
7
votes
5
answers
2k
views
Do contra-rotating propellers have the same RPM?
Image source
Here is a contra-rotating propeller. The front propeller rotates counterclockwise while the back propeller rotates clockwise. My questions are:
Do they rotate at the same speed (RPM)?
...
- 4,411
6
votes
4
answers
11k
views
Are there disadvantages of coaxial rotor on attack helicopters?
Although the Ka-52 Alligator is a very fierce-looking and formidable aircraft with very powerful engines, it has not seen much export success. Its export is very limited, as only Egypt uses this type ...
user8792
25
votes
8
answers
31k
views
What is the purpose of having contra-rotating props on an aircraft?
Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose?
Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
- 5,669