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vincenzino montella
2nd Jul 2013, 09:33
Hi everybody,
I wish to ask if the T.O & LNDG crosswind components were different (right and left), due the offset position of the nosewheel gear.
Thank you for any help :)

Allan Lupton
2nd Jul 2013, 14:35
I can't think of any reason why the fact that the nosewheels were not on the centreline should make any difference. There have been a lot of technically unsound rumours about the DH121 nosegear, and perhaps this question has its origin in one of those rumours.
In case it helps, consider taking moments about the CofG and tell me if equal left and right steering forces give different yawing moments.

vincenzino montella
2nd Jul 2013, 19:27
The airline which I served as a B744 driver there was a TRE/TRI ex BA, coming from BEA.
He used to fly the Trident during his early years as a pilot.
During a conversation on our aviation beginnings he mentioned his experience on the Trident and this particular issue...I didn' pick up any "joking" mood at that time...and let the thing finish there.
Few years later, talking with another retired B74 captain about our nostalgic years, I came back to this issue and we tried to figure out the "aerodynamic" reason behind that...we came to no conclusion...and I lost my ex BA friend's telephone number...

Meikleour
2nd Jul 2013, 19:36
The T1 and T2 variants had similar crosswind limits from each side however I believe that the T3B had different crosswind limitations for each side caused I believe by the Boost Engine or the APU inlet affecting the rudder.
Nothing to do with the offset nosewheel.

Aileron Drag
2nd Jul 2013, 19:51
The offset position of the nose-wheel was completely irrelevant to the operation of the aircraft.

In no respect was it considered, mentioned, or even thought about by the flight crews.

Except...................:)

Come to think of it, upon dropping the gear, you'd give a turn or two of right rudder trim.

That was the only effect upon the operation.

millerscourt
3rd Jul 2013, 06:58
Allan Lupton

On my licence which has just been carbon dated it shows it as HS121 not DH

Rocket2
3rd Jul 2013, 09:34
So why was the nose gear offset?

Allan Lupton
3rd Jul 2013, 10:06
Millerscourt
Most of the Tridents were made after HSA had dropped the de Havilland name but that doesn't mean it wasn't a DH type number when originally designed, that number having been used from the (Airco) outset.

Rocket2
The offset was so that the gear could retract sideways thus having a short but wide bay and permitting a bigger avionics bay behind it. A conventional nose gear bay would have left a couple of long thin voids either side which would have been difficult to access so little use for the avionics of the day.
ETA
Oh and although I'm not a structural engineer I'd say the pressure floor required is shorter, so easier to support .

vincenzino montella
7th Jul 2013, 09:03
Thank you for all the comments...I appreciate a lot the time spent by you on commenting this "rumour"... even if it still remains "half rumour" now...cheers...:)

Shaggy Sheep Driver
7th Jul 2013, 09:34
Wasn't the dH 121 a completely different aeroplane? The aeroplane dH wanted to build before BEA mandated only 90 seats? It was to have the proposed RR Medway engine, but when downsized to 90 seats and given a 'T' tail the Medway wasn't required and Speys were fitted.

The Trident 3 was 'dH 121 - sized' and could have done with the Medway, hence its boost engine to augment the 3 Speys in 'hot and high' T/Os.

DaveReidUK
7th Jul 2013, 09:51
Wasn't the dH 121 a completely different aeroplane? The aeroplane dH wanted to build before BEA mandated only 90 seats?No.

BEA ordered the DH121, in its revised configuration, the year before de Havilland was bought by Hawker Siddeley, and several years before the DH121, DH125, etc were re-designated as HS.

Mike6567
7th Jul 2013, 13:03
I thought it was something to do with making room for possible exit stairs incorporated in the aircraft below the front left door?
This was not used on the Trident so external steps were required (though not required on the B727 as it had the rear stairway)

wrecker
7th Jul 2013, 14:27
My first type rating on the Trident was listed as DH121 on my licence.

scotbill
16th Jul 2013, 10:23
One advantage of the offset nosewheel was that it saved the first class pax from the thump, thump of running over the runway centre line lights!

The T3 had the same Xwind landing limit of 30k as the 1 and 2 - but on T/O they were permitted 35k while the T3 was restricted to 30k when the Xwind was from the right, further restricted when the Xwind was from the left to 25k dry and 20k wet.
(No mention of boost being a factor).

For the life of me I can't remember the reason but don't recall any problem with Xwinds with intelligent use of aileron.

vincenzino montella
17th Jul 2013, 10:31
Thank you scotbill!
I appreciate a lot your input which reinforces my confidence to my friend exBA-exBEA for this issue: he wasn't pulling my legs...:D
What I understand is that on that particular type (T3), there was anyway a difference between T.O and LNDG xwind components: none for the landing and 5 knots for take off.
At first sight, I could assume that, being the difference equal to zero for landing, a thrust asymmetry (which doesn't exists on landing, due to the engines @ idle) could play a role on take off.
If the limitatation is higher for a left xwind component (and the nosewheel is left offset) I dare to say that, if the RIGHT engine fails between V1 and Vr, a "normal" right rudder displacement to keep the aircraft centerlined in this xwind situation, combined with the sudden swing to the right, might lead to a momentary substancial unnbalance in lateral control (before modulating the left rudder).
Reducing the allowed xwind component from left, in the above case, the right rudder displacement would be lower so maybe not so initially critical to maintain direction in spite of the swing to the right due to the right engine failure...within the allowed limits, of course...
Should these considerations be near to the truth, it would mean that the "funny geometry" of the three landing gear struts have played a role on this xwind different limitations...
Any comment?

blind pew
17th Jul 2013, 11:21
Might be wrong but seem to remember that the different xwind limit was because of disturbed airflow into the boost engine.....
Fortunately I didn't stay long enough to fly the combined fleet as I went to fly a proper kite...the Iron Duck.