Moderators: richierich, ua900, PanAm_DC10, hOMSaR
SWALUV wrote:Correct me if I'm wrong, but I believe the main reason T-Tail aircraft aren't designed more often is simply because of the added weight needed for structural purposes.
I would love to see another modern T-Tail though. That'd be gorgeous!
jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Veigar wrote:jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Weren't they aiming to do something similar with the 7J7? I believe it looked identical to a 727 minus the s-duct engine
TWA772LR wrote:Veigar wrote:jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Weren't they aiming to do something similar with the 7J7? I believe it looked identical to a 727 minus the s-duct engine
A 3-engine, UDF, T-tail, MoM plane would be the coolest airliner to grace the skies since Concorde. Would have to have a super tall landing gear so the fans don't hit the runway upon take off, but who cares? That would be one sexy machine! Like the love child of a 727 and Q400!
seabosdca wrote:If NMA as currently imagined sees the light of day, the oval fuselage will be quite striking and prevent any chance of it being "cookie cutter."
Veigar wrote:SWALUV wrote:Correct me if I'm wrong, but I believe the main reason T-Tail aircraft aren't designed more often is simply because of the added weight needed for structural purposes.
I would love to see another modern T-Tail though. That'd be gorgeous!
Yeah, I had thought this to be the case, but on the flip side, aren't T-Tail airplanes more aerodynamic?
Veigar wrote:jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Weren't they aiming to do something similar with the 7J7? I believe it looked identical to a 727 minus the s-duct engine and the weird propfans.
Veigar wrote:jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Weren't they aiming to do something similar with the 7J7? I believe it looked identical to a 727 minus the s-duct engine and the weird propfans.
kurtverbose wrote:...er, isn't deep stall an issue?
Apart from that I think yes, Boeing should focus more on styling and heritage rather than aerodynamics and efficiency.
JannEejit wrote:Veigar wrote:jubguy3 wrote:Yes, because Boeing's primary concern is to make a throwback aircraft.
Weren't they aiming to do something similar with the 7J7? I believe it looked identical to a 727 minus the s-duct engine and the weird propfans.
Wasn't it supposed to have a t-tail and under wing slung engines ?
http://www.boeingimages.com/archive/Ear ... OIYZR.html
kurtverbose wrote:...er, isn't deep stall an issue?
bennett123 wrote:The HS Trident was a T tail.
Got into a stall soon after take off.
The wing masked the tail plane and the result was a flat spin.
SWALUV wrote:Correct me if I'm wrong, but I believe the main reason T-Tail aircraft aren't designed more often is simply because of the added weight needed for structural purposes.
I would love to see another modern T-Tail though. That'd be gorgeous!
Veigar wrote:JannEejit wrote:Wasn't it supposed to have a t-tail and under wing slung engines ?
http://www.boeingimages.com/archive/Ear ... OIYZR.html
That's a good point. To my knowledge, no mass produced aircraft looks like this - correct me if I'm wrong, of course. Wonder why no manufacturer made an airplane like this.
Veigar wrote:Wow, VirginFlyer, that was a very well constructed post that answered practically every question I've had in my mind about aircraft design. Thank you!
I suppose none of that applies to smaller airplanes though, since T-tailed business jets seem to be the most common (At least in LAS, practically every business jet is a T-tail or cruciform tail). Heck, there are business jets that look exactly like the 727 (even with the 3rd s-duct tail engine) that are commonly used today still. Wonder why that is... another notable example I can think of is the C-5 Galaxy, but since it's a cargo plane, I can only guess that it's a T-Tail for the back cargo door to be easier to open.
Faro wrote:As others have indicated, T-tails are definitely out for airliners due to the structural weight penalties...
It is no coincidence that Airbus, Boeing, Bombardier, Embraer, the Russians, etc all produce similar low wing-podded twin-engined airliners...everyone has arrived at the same conclusion...this is the most efficient design template possible given the present state of technology...
Ubiquitous, sad and boring bleating of airline industry herds worldwide...but nonetheless very efficient...
Faro
JCTJennings wrote:Faro wrote:As others have indicated, T-tails are definitely out for airliners due to the structural weight penalties...
It is no coincidence that Airbus, Boeing, Bombardier, Embraer, the Russians, etc all produce similar low wing-podded twin-engined airliners...everyone has arrived at the same conclusion...this is the most efficient design template possible given the present state of technology...
Ubiquitous, sad and boring bleating of airline industry herds worldwide...but nonetheless very efficient...
Faro
Basically, Boeing got it right in 1954 with the 367-80 and today all airliners are built in it's image, other than number of engines.
mats01776 wrote:3) Put the enpenage's control surfaces far away from the center of lift for efficiency.
Veigar wrote:Hm. All of the points posed here bring up the question as to why Boeing even did the design they did when developing the 727. If anything, the rear end of the 727's area (everything where the tail is) would be even HEAVIER with the middle engine that has the S-duct inlet. Also, do low bypass engines only work on this type of aircraft? (If it's as big as the 727 or 757 obviously) I know for a fact no manufacturer will make a plane nowadays with low bypass engines, so it'd make sense as to why it could've worked back then and not now.
phelpsie87 wrote:Similar size? Seriously?
JCTJennings wrote:Faro wrote:As others have indicated, T-tails are definitely out for airliners due to the structural weight penalties...
It is no coincidence that Airbus, Boeing, Bombardier, Embraer, the Russians, etc all produce similar low wing-podded twin-engined airliners...everyone has arrived at the same conclusion...this is the most efficient design template possible given the present state of technology...
Ubiquitous, sad and boring bleating of airline industry herds worldwide...but nonetheless very efficient...
Faro
Basically, Boeing got it right in 1954 with the 367-80 and today all airliners are built in it's image, other than number of engines.
VirginFlyer wrote:Veigar wrote:Hm. All of the points posed here bring up the question as to why Boeing even did the design they did when developing the 727. If anything, the rear end of the 727's area (everything where the tail is) would be even HEAVIER with the middle engine that has the S-duct inlet. Also, do low bypass engines only work on this type of aircraft? (If it's as big as the 727 or 757 obviously) I know for a fact no manufacturer will make a plane nowadays with low bypass engines, so it'd make sense as to why it could've worked back then and not now.
When the 727 was designed, there weren't high bypass turbofans; the JT8D was basically it. They needed three engines for performance. I am under the impression podded engines under the wing were discounted in favour of getting a cleaner wing to enable better field performance. The rest of the design would have flowed on from that.
V/F
SWALUV wrote:Correct me if I'm wrong, but I believe the main reason T-Tail aircraft aren't designed more often is simply because of the added weight needed for structural purposes.
I would love to see another modern T-Tail though. That'd be gorgeous!
Apprentice wrote:Hello: T-Tail a/c were not made first by Boeing. First commercial a/c with engines on Tail and T-tail was Caravelle. And they applied for a patent, so, anyone who followed them, fisrt had to pay the french..
Rgds
Florianopolis wrote:Help me understand this, please.
In favor of the T-Tail and fuselage-mounted engines, we have:
- Smaller, lighter landing gear.
- Smaller horizontal stab (longer arm)
- Smaller vertical stab and rudder (less asymmetric thrust)
- Smaller wing for the same performance (no engines messing up your aero)
And all of that is more than offset, at least on large transport aircraft, by
- wing bending relief
- vertical stab structural weight
phelpsie87 wrote:Similar size? Seriously?
Starlionblue wrote:VirginFlyer wrote:Veigar wrote:Hm. All of the points posed here bring up the question as to why Boeing even did the design they did when developing the 727. If anything, the rear end of the 727's area (everything where the tail is) would be even HEAVIER with the middle engine that has the S-duct inlet. Also, do low bypass engines only work on this type of aircraft? (If it's as big as the 727 or 757 obviously) I know for a fact no manufacturer will make a plane nowadays with low bypass engines, so it'd make sense as to why it could've worked back then and not now.
When the 727 was designed, there weren't high bypass turbofans; the JT8D was basically it. They needed three engines for performance. I am under the impression podded engines under the wing were discounted in favour of getting a cleaner wing to enable better field performance. The rest of the design would have flowed on from that.
V/F
Another point is that airstairs, including integrated ones, were the norm at the time, so a design with the doors further from the ground had disadvantages.
I fondly remember disembarking from the rear airstairs on the 727. Like emerging from the bowels of a mechanical beast.
To VirginFlyer's point, look at how tiny those engines seem compared to today's designs.
Faro wrote:Starlionblue wrote:VirginFlyer wrote:When the 727 was designed, there weren't high bypass turbofans; the JT8D was basically it. They needed three engines for performance. I am under the impression podded engines under the wing were discounted in favour of getting a cleaner wing to enable better field performance. The rest of the design would have flowed on from that.
V/F
Another point is that airstairs, including integrated ones, were the norm at the time, so a design with the doors further from the ground had disadvantages.
I fondly remember disembarking from the rear airstairs on the 727. Like emerging from the bowels of a mechanical beast.
To VirginFlyer's point, look at how tiny those engines seem compared to today's designs.
On a side-note...I continue to be amazed by the magnificently sleek and elegant lines of the 727-200...nothing comes close to it in beauty and elegance...that swept-back, streamlined empannage is pure design magic...
Faro
Starlionblue wrote:Faro wrote:Starlionblue wrote:
Another point is that airstairs, including integrated ones, were the norm at the time, so a design with the doors further from the ground had disadvantages.
I fondly remember disembarking from the rear airstairs on the 727. Like emerging from the bowels of a mechanical beast.
To VirginFlyer's point, look at how tiny those engines seem compared to today's designs.
On a side-note...I continue to be amazed by the magnificently sleek and elegant lines of the 727-200...nothing comes close to it in beauty and elegance...that swept-back, streamlined empannage is pure design magic...
Faro
Quite right. I'd say the VC-10 is up there as well, for the same reasons.
Veigar wrote:phelpsie87 wrote:Similar size? Seriously?
Go compare it for yourself - the 727-200 and 757-200 are almost the same length. There's a reason the 757 was a 727 replacement after all!
kurtverbose wrote:D.B. Cooper killed off the rear air stairs. Just too tempting for passengers to try a parachute jump from.
Veigar wrote:I honestly doubt this was the reason. That incident occurred in 1971, and 727s have been used throughout the years even to this day. If he was the reason the rear stairs were canned, then you'd likely have seen major design modifications from 727s back when their production was still going.
Moose135 wrote:Veigar wrote:I honestly doubt this was the reason. That incident occurred in 1971, and 727s have been used throughout the years even to this day. If he was the reason the rear stairs were canned, then you'd likely have seen major design modifications from 727s back when their production was still going.
727s in the United States were modified following the Cooper hijacking. The FAA ordered the installation of a device usually referred to as a Cooper Vane. This was a spring-loaded vane, moved by airflow once airborne, that prevented the rear air stair door from opening in flight. Once back on the ground, the spring would move the vane away from the door, allowing it to be opened after landing.