Bae 146 Q
Aerodynamics, structure, aesthetics and ergonomics.
They look better that way. It would look like crap with a straight wing and even worse with dihedral(like some of those Russian ones
).
Be interested in other thoughts and let me know who wins
.
In the meantime I had better take cover
.
They look better that way. It would look like crap with a straight wing and even worse with dihedral(like some of those Russian ones
).Be interested in other thoughts and let me know who wins
.In the meantime I had better take cover
.
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Aircraft with both swept and high wings ( like the BAe 146 ) are often too stable, and this is corrected by incorporating anhedral (negative dihedral.) 
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Because it was designed by the Poms...and since the Spitfire they have lost the plot!
Did you know it takes two hours to do the initial acceptance check on the "jet you have when you don't have a jet" ?
Did you know it takes two hours to do the initial acceptance check on the "jet you have when you don't have a jet" ?
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To add to what the learned Lame has said, high wing increases lateral stability (due to Lift/Weight moment and fuselage blanketing). This makes any decent roll rate difficult, so most high wing aircraft have a straight or anhedral wing to reduce lateral stability back into the ideal range. I guess the Russians just decided to up-size their roll control systems - of course anything of reasonable size (AN124, AN225) also uses anhedral.
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Thanks for the replys gentleman.
I agree hoss the 146 would indeed look even worse with dihedral. So im sure that being a high wing with limited sweep that lame was correct once again with anhedral being incorpated into the 146 to reduce lateral stability.
Beers all round for those that replyed.
Just as an interesting story on the side. I would have asked one of the 146 drivers the same question but last time I asked the NJ boys a question relating to their machines ie "whats it like to fly a jet with hair dryers for engines" the response was something like "it has quite good one engine inop performance you will find, my good chap"
Snapper
I agree hoss the 146 would indeed look even worse with dihedral. So im sure that being a high wing with limited sweep that lame was correct once again with anhedral being incorpated into the 146 to reduce lateral stability.
Beers all round for those that replyed.
Just as an interesting story on the side. I would have asked one of the 146 drivers the same question but last time I asked the NJ boys a question relating to their machines ie "whats it like to fly a jet with hair dryers for engines" the response was something like "it has quite good one engine inop performance you will find, my good chap"
Snapper
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Snapper head, all that confirms is that the NJ lads you know are the gentlemen that I know.
Your normal aussie pilot, when asked an insulting question by a dork, would punch the dork in the nose
Instead, you got a civil answer. Ergo, you have encountered a phenomenon known as.. a gentleman.
Your normal aussie pilot, when asked an insulting question by a dork, would punch the dork in the nose
Instead, you got a civil answer. Ergo, you have encountered a phenomenon known as.. a gentleman.
Amos2,
B#ll****.
PS: You're obviously an ex-Ansett w#nker. It's a "Safety and Power On" check!
B#ll****.
PS: You're obviously an ex-Ansett w#nker. It's a "Safety and Power On" check!
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Well you learn something every day...I thought the wings were anhedral so as to keep the fumes inside the a/c 
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The ATR is a high wing aircraft (god help me if ive got this bit wrong), and i have noticed on Take-off the wings bend a long way upwards, giving an amount of dihedral
Any ATR pilots want to comment on its stability, is it slow in the roll? Require a lot of aileron?
Any ATR pilots want to comment on its stability, is it slow in the roll? Require a lot of aileron?
Sorry to disappoint so many budding aerodynamicists – yes anhedral is used to modify stability, but usually on swept back wings. The 146 has sweep back??!!
The aerodynamic design of the 146 was for zero anhedral, but the structural design pre loads the wing so that on the ground there is the appearance of anhedral. When the wing is loaded in flight everything is straight and level.
The aerodynamic design of the 146 was for zero anhedral, but the structural design pre loads the wing so that on the ground there is the appearance of anhedral. When the wing is loaded in flight everything is straight and level.
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safetypee,
I wonder if you are referring to the same 146 as we are -- the BAe146?
This aeroplane has 15 degrees of wing sweep, and anhedral. I can assure you that every time I have looked out my window whilst airborne, the wings did not bend up to become 'straight and level.' Even when I have had 6 full strength coffees on a 3hr50min YBAS-YPPH sector!
I wonder if you are referring to the same 146 as we are -- the BAe146?
This aeroplane has 15 degrees of wing sweep, and anhedral. I can assure you that every time I have looked out my window whilst airborne, the wings did not bend up to become 'straight and level.' Even when I have had 6 full strength coffees on a 3hr50min YBAS-YPPH sector!
My coffee was drunk a few offices away from that of the BAe146 chief designer.
In addition to spending several years looking at the design drawings; I also have many enjoyable hours in the air looking at most of the 146 features.
In addition to spending several years looking at the design drawings; I also have many enjoyable hours in the air looking at most of the 146 features.
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hmm, safetypee, interesting.......
The BAe Hatfield manufacturer's operations manual first paragraph introduces the aeroplane as...
"The BAe 146 is a short range subsonic transport monoplane, powered by four Avco Lycoming turbofan engines, pylon mounted, below a high swept wing."
The BAe produced AV presentation for pilot groundschools describes the wing as having 15degree sweepback and 3 degrees anhedral.
Sweep:
Maybe not the degree of sweep found on a Mirage or B747, but swept. The manufacturer's directions on aircraft handling are also those influenced by swept wing characteristics. Sweep is mild yes, evidenced by the fact that yaw dampers are fitted and yaw damper inoperative is an abnormal condition, but dispatchable with the limitation of a (reasonably high) IAS, no altitude restrictions, and in the -300 series with its longer fuselage, there are no operational limits for flight with yaw damper inoperative.
As for the nil anhedral in flight, hmmm!
3 degrees over approximately 23m span, means that the tip is about 600mm lower than the wing root.
The tips do not move 600m up after rotation, I can assure you -- even a brash colonial would notice that!
Conversations with our engineers that have recently done wing spar inspections and mods have them saying that the 146 has a much more rigid wing than Boeing products that some have worked on. Very little flex in the 146 was the report.
Also remember that the anhedral has been used as an important feature of the 'wet' wing fuel tanks -- the contents of the main tanks gravity feed to "feed" (header) tanks located near the tips, which then feed the engines.
Again, from the BAe Hatfield manual, after discussion of electric and hydraulically operated fuel system pumps....
"Gravity feed from wing tanks will ensure normal engine operation up to at least 20,000 feet."
So the asserted 'nil anhedral in flight' contradicts a major fuel system design feature, as well as my own looking out the window..
However, as always, I would be happy to accept an authoritative source as a contradiction.
The BAe Hatfield manufacturer's operations manual first paragraph introduces the aeroplane as...
"The BAe 146 is a short range subsonic transport monoplane, powered by four Avco Lycoming turbofan engines, pylon mounted, below a high swept wing."
The BAe produced AV presentation for pilot groundschools describes the wing as having 15degree sweepback and 3 degrees anhedral.
Sweep:
Maybe not the degree of sweep found on a Mirage or B747, but swept. The manufacturer's directions on aircraft handling are also those influenced by swept wing characteristics. Sweep is mild yes, evidenced by the fact that yaw dampers are fitted and yaw damper inoperative is an abnormal condition, but dispatchable with the limitation of a (reasonably high) IAS, no altitude restrictions, and in the -300 series with its longer fuselage, there are no operational limits for flight with yaw damper inoperative.
As for the nil anhedral in flight, hmmm!
3 degrees over approximately 23m span, means that the tip is about 600mm lower than the wing root.
The tips do not move 600m up after rotation, I can assure you -- even a brash colonial would notice that!
Conversations with our engineers that have recently done wing spar inspections and mods have them saying that the 146 has a much more rigid wing than Boeing products that some have worked on. Very little flex in the 146 was the report.
Also remember that the anhedral has been used as an important feature of the 'wet' wing fuel tanks -- the contents of the main tanks gravity feed to "feed" (header) tanks located near the tips, which then feed the engines.
Again, from the BAe Hatfield manual, after discussion of electric and hydraulically operated fuel system pumps....
"Gravity feed from wing tanks will ensure normal engine operation up to at least 20,000 feet."
So the asserted 'nil anhedral in flight' contradicts a major fuel system design feature, as well as my own looking out the window..
However, as always, I would be happy to accept an authoritative source as a contradiction.