21
votes
Why isn't the rudder below the tail?
It is bad to put things below the tail because they might hit the ground. Even with nothing below the tail sometimes there is still a tail strike.
http://avherald.com/h?article=42b2d053
- 3,461
20
votes
Accepted
Are there any known aircraft (experimental, otherwise) with non-fixed vertical/horizontal stabilizers?
The SR-71's rudders pivoted without any fixed leading edge, as shown:
Source
Source
The T-38 (along with many other supersonic jets of its era) had a pivoting horizontal stabilizer with no fixed ...
- 52.6k
18
votes
Accepted
Why are the leading edges on the Boeing 787 made from aluminum?
There are probably many factors in choosing aluminum vs. composites.
A big one is bird strikes. The leading edges are at the highest risk for this. Metal tends to absorb the impact better while ...
- 73.5k
18
votes
Accepted
Why are there double hinge lines on the rudders of the Grumman C-2?
The double hinged rudder is also a Dehavilland Canada feature on most of its larger designs like the Caribou/Buffalo/Dash 7/Dash 8, where maximum yaw power for a given surface area was a design ...
- 134k
16
votes
Why isn't the rudder below the tail?
The MQ-1 Predator does have a V-tail ruddervator below the tail.
Does the Predator drone's design make a tail strike more likely on takeoff and landing?
The MQ-1 is already at high risk of a rear ...
- 3,461
16
votes
Accepted
What are those little pieces for on the C27J?
Those are vortex generators. In this case they are to mitigate bad handling if it loses the “worst case” (critical) engine:
Seventeen vortex generators were added to the left-hand side of the ...
- 2,801
15
votes
Accepted
What is the difference between a vertical stabilizer and a rudder?
The vertical stabilizer is immobile (if it starts to move, you're in deep shit), and provides stability in yaw (it keeps the aircraft pointed more or less in the direction that it's moving).
The ...
- 28.5k
15
votes
Are there any known aircraft (experimental, otherwise) with non-fixed vertical/horizontal stabilizers?
Many aircraft use an all-moving horizontal tail—with or without an elevator.
Fighter aircraft (F-15, F-22, F/A-18, etc.) often use an all-moving tail without elevators. This gives superb control ...
- 15.6k
14
votes
Why are there double hinge lines on the rudders of the Grumman C-2?
2 hinge lines will give the rudder more authority because it will direct the air more aggressively. We can think of rudders as vertical and two way extending flaps. It's like the difference between a ...
- 467
12
votes
Are there any known aircraft (experimental, otherwise) with non-fixed vertical/horizontal stabilizers?
In the light aircraft world, plenty of designs use non fixed horizontal tails, called, "stabilators" or "all flying tails" when they first came out. With unpowered controls, you ...
- 134k
11
votes
Is a vertical stabiliser needed for straight line flight in a glider?
The stabilizer is meant to keep the nose pointing into the wind.
Any asymmetry in he wings/fuselage will create a tendency to yaw, you will need to compensate for that. The easiest is a fixed ...
- 27.5k
11
votes
Why isn't the rudder below the tail?
Why isn't the rudder below the tail?
Compromises, as usual in the aerospace world.
From an aerodynamic and flight mechanics point of view the best location for the vertical tailplane would be ...
- 14.6k
10
votes
Accepted
What is the best procedure if the rudder falls off?
Aircraft can be flown without a rudder if the vertical stabilizer is still there. There are many pictures of aircraft landing safely after losing the rudder only, and still having the vertical ...
- 13.2k
9
votes
Accepted
Is there a formula to calculate how big a ventral fin should be?
There is no single formula - the number of factors to consider are too numerous and the load cases are too diverse. Here is an incomplete list:
Directional stability: Depending on fuselage size and ...
- 236k
9
votes
Is a vertical stabiliser needed for straight line flight in a glider?
The underlying function of a VTP (not rudder) is mitigating the lateral-directional eigenmodes of the aircraft (Dutch roll, spiral divergence and roll subsidience). Unless you can guarantee a perfect ...
- 8,611
9
votes
What is this mysterious thing on the vertical stabilizer of the Boeing 707?
It is the high-frequency shortwave antenna of a 707-321B, specifically Clipper Yankee Ranger N418PA. Also present on the KC-135.
You can read about the Antenna Coupler Program from the people ...
- 14.2k
8
votes
Why is a blunt trailing edge a better stabilizer at hypersonic speeds?
A converging shape at hypersonic speed in a low-pressure medium will produce close to vacuum pressure on its surfaces (hypersonic shielding). A small sideslip angle will only result in a very small ...
- 236k
8
votes
Are there any known aircraft (experimental, otherwise) with non-fixed vertical/horizontal stabilizers?
I think fully-flying control surfaces are too common to merit a mention. Especially for supersonic airplanes they are de rigeur.
But there is one design which had a variable-sweep control surface: The ...
- 236k
7
votes
What is the correct procedure in case of vertical stabilizer failure?
There is no procedure, generally a vertical stabilizer failure makes an airplane uncontrollable, meaning everyone dies. There have been examples where vertical stabilizers failed and people survived, ...
- 54.2k
7
votes
Is a vertical stabiliser needed for straight line flight in a glider?
It's unlikely that your project will succeed without a vertical fin. Are you aware that there are countless radio-controlled model airplanes and gliders that feature a fixed vertical fin but no ...
- 23k
7
votes
Could the vertical stabilizer be removed on the NASA X-57?
Differential thrust is not a good way to control the yaw of an airplane. For one thing thrust control has to be extremely quick, if it takes even a second between a control input and the thrust ...
- 54.2k
7
votes
Why are Vertical tails generally tapered?
The vertical tail and the horizontal tail are wings, and follow the same construction rules. The span-wise lift distribution is much better if the wing is tapered: more lift at the root, less at the ...
- 62.3k
6
votes
Why aren't there aircraft with forward-mounted vertical stabilizers?
From the image you can see that a vertical stabilizer mounted behind the aircraft CG imparts a restoring moment to a yaw disturbance which increases as the yaw movement increases. If the fin were ...
- 20.9k
6
votes
What is the aerodynamic reason that the An-225's vertical stabilizers are not simply vertical?
I'm fairly sure (but have no sources to confirm) that the reasons are purely structural. The vertical stabilisers are simply set at a right angle to the horizontal one. This is just the easiest thing ...
- 9,103
6
votes
Why was the tip of the B-52's vertical tail chopped off in 1959?
Boeing B-52G Stratofortress
In the design of the B-52G, considerable attention was paid to reducing the structural weight. Different materials were used in the construction of the airframe, and the ...
- 37.9k
6
votes
Accepted
How do I choose the vertical tail's airfoil?
Normally, you would pick a symmetric airfoil. The thickness should be between 9% and 15% to find a good compromise between structural efficiency and maximum side force. Choose a thicker airfoil at the ...
- 236k
6
votes
Accepted
Could the folding wingtips of a plane (ex. F-35C) be used as a vertical stabilizer?
If the vertical wing tips have aerodynamic centers that are aft of the center of mass, there will be some yaw stabilizing effect by the tips.
Problem is, the effect will be quite minor, the arm being ...
- 134k
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