Cautrell05

I was at the airshow in omaha a couple of weeks ago and there was a B52 there. What I really dont understand is how the plane banks. On both wings there was only 2 very large flaps on each wings but nothing that looked like ailerons. Both flaps had a very large s crew drive to control movement. What did I miss?
Nick

encan

Spoilers maybe?

Taildragger726

Spoilers only,,,like a MU-2,,

LearjetMech

and a beechjet!!

William Robison

My Feedback: (3)

[b]And the roll response? Ask any Buff driver. Pull the belt out of your pants and tie the wheel at full left, go get a cup of coffee, then come back and untie the wheel to roll out in another three or four minutes. Well, not quite that bad, but it was RREEAALLYY slow in roll.

Bill.

flyinrazrback

My Feedback: (69)

Well, as a B-52 pilot myself, I can attest its not the most agile plane, as it was not designed as such. It was designed to make cities and civilizations dissapear. It has spoilers, which just kill lift on one wing to make it drop and hence turn the airplane. Some of the older versions had ailerons, but they put too much strain on the wing, so they went with spoilers.

Wayne22

My Feedback: (2)

I've heard a similar description used for the PBY

William Robison

My Feedback: (3)

[b]I've crawled through PBYs, but never flown one. But I can't believe the roll response could be as bad as the B-52.

People who have flown the PBY variants tell me the worst thing about them is a failure shortly after take off - all the fuel weight in the wings makes the plane's surviving the landing a matter of luck. No, they didn't have any means of dumping fuel.

Bill.

William Robison

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[b]Razorback:

You have the experience, tell us some of your horror stories about flying a short final in a B-52. I know you've had "Final Fun" a time or two.

Bill.

flyinrazrback

My Feedback: (69)

Not really any horror stories to talk about. The airplane is very stable, and the only challenge is heavy cross winds, but the crosswind crab system helps with that a lot. It can get difficult when you have multiple engines out on one side. Most emergencies require us to burn down fuel to lightweight, so that takes a lot of the variables out of EPs down final approach. On another note, the only difficulty in general is its a very physically challenging plane to fly, especially if you have to fly long times without the autopilot. 2-3 hours in just the pattern autopilot off will wear you out.

Chasing Fear

My Feedback: (1)

The B-52, like some airliners, didn't have ailerons because of control reversal.

With the long, thin wing, a deflected aileron could actually make the wing twist. The down deflected aileron would lift only the trailing edge of the wing, causing an effective negative AoA.

The result would be a left bank when a right bank was commaned, or vice versa.

I used to fly KC-135s ... we had ailerons, but the outboard ailerons only worked at low speeds (flap lockout) for the very same reason.

-Allan

flyinrazrback

My Feedback: (69)

they removed ailerons in BUFFs because the twisting of the wing was deteriorating the wing structure over time, thus resulting in them switching to just spoilers. It works fine, just flies heavy.

Blue_Moon_

this is so cool. this place really swarming of pilots

Is it easy to become a pilot in the USA?

William Robison

My Feedback: (3)

BM:

Quote:

Is it easy to become a pilot in the USA?

It just takes money. For one class you don't even have to pass a medical exam.

Bill.

HalH

My Feedback: (12)

I would disagree that the outboard ailerons were used only with flaps extended to prevent wing twisting. The inboard aileron was all that was neadded at high speed for adequate control. The spoilers were active in all flight configurations. The outboard ailerons were needed only at landing speeds.

HalH

My Feedback: (12)

What airliner has no ailerons ?

LearjetMech

Not sure what you mean or where you are headed on this one Hal

This is quoted out of a lab book I had in A&P school published by American Airlines concerning the 747.

"Lateral control is accomplished by using the inboard and outboard ailerons and flight spoliers. At low speeds, with flaps extended, both inboard and outboard ailerons, as well as flight spoilers are utilized. As flaps are retracted above position one, the outboard ailerons are electrically locked out."

LearjetMech

The Concorde did not have "ailerons" and it was an airliner!

HalH

My Feedback: (12)

Your right it had elevons. Can you name any others ? None come to my mind.

The 707 and 727 ailerons, spoilers and flaps operate similar to the 747. There were inboard and outboard flight spoilers and ground spoilers. Flight spoilers were also used as speedbrakes in that all could be raised at once. The flight spoilers and ground spoilers were used to aid in stopping.

Bax

My Feedback: (11)

Yah....I remember reading a long time ago in Flying Magazine that for very rapid descents in teh B707 thatthe speed brakes could be deployed and the inboard engines put into reverse. Plane would shudder, rattle, and shake, and plummet like a stone. I have been in flights where the B727 I was in had full speed brakes deployed to help descent. Coming into San Diego one time, the pilot was held high until rather close, and then given a steep descent profile. Plane still shook a lot!.

Just like full-performance takeoffs...they don't like to fly like that because it scares the passengers....

LearjetMech

I have heard the C17 can also do the in flight TR deployment referred to as a "Tactical Decent". Not sure if 2 or 4 engines do it though!!

HalH

My Feedback: (12)

The 707 never used thrust reversers in the air. They however could use the main landing gear. The early DC-8s could use thrust reversers inflight. The simultaneous use of flaps and spoilers was not authorized for use on the 727 because of the extremely high sink rate. Not a good idea near the ground !

Question: What is a high performance takeoff ? how's it done ?

LearjetMech

Hal,
You brought up some of the same things that ran through my head when I read the last post. I thought all take-off's were high performance.

HalH

My Feedback: (12)

Airlines have been using reduced thrust takeoffs for a long time. It is rather complicated to explain but it basically is assuming a temperature that is higher than actual and using the minimum thrust required to takeoff on that runway at the actual weight of the aircraft at the assumed temp. Clear as mud ???

Jimmbbo

To oversimplify the situation, using full rated thrust on takeoff assures that the airplane will be able to lose an engine and climb away from the airport with the airplane at its maximum certificated takeoff weight at normally anticipated temperatures and altitudes on a "normal" length runway. However, high power settings result in high temperatures that reduce turbine engine life, so the reasoning for using reduced thrust is "Why use all the thrust the engine can produce if you only need 80% of it to ensure a safe single engine climb away from the airport?"

If the airplane departs an airport at less than its maximum weight, or on a cold day, or on a loonnnng runway, less thrust is required to assure the same engine-out safety margins. To figure out how much thrust reduction is allowable while still ensuring single engine climb performance, the performance gurus program their computers with all the relevant data, and a thrust reduction is calculated and presented in a document usable by flight crews.

The generic name for this document is the Runway Analysis Manual, and it consists of hundreds of pages of data for each runway at each airport the airline will be using considering all possible air temperatures and aircraft weights.

Cheers!

Jim