Different T.O & LNDG xwind components for H.S. Trident
 

Hi everybody,
I have this question following a story by a Trident pilot during the 80s...he declared that the Trident had different cross wind components for take off and landing due to the offset position of the nosewheel gear.
As I can't figure out this behavior and after I made a lot of researches on the net, this will be my last attempt on this issue: anybody has any information?
Thank you very much for attention.
Happy New Year to everybody!

I think what you are referring to was the Trident 3B which did have a different crosswind limit on each side due to the placing of the boost engine and the APU. I believe the other marks ie. 1 & 2 did not have this "quirk". I am sure more knowledgeable posters will confirm this.

Thank you very much for your comment, Meikleour!
Actually I was caught by this "quirk" from that great plane, never heard something similar in my long career...about 40 years...
Can you remember any detail on that particular "geometry" affecting the different response on crosswind components?
Thank you again.
Have a great New Year.

Does the OP mean a different x-wind from the left or right or the same from left and right but different for T/O and landing?

I have it in my mind that the 146 had a different for T/O than landing but I can't find my manuals. I last flew it in 1998 but I seem to recall 31kts for T/O and 35kts for landing.

Hi, Flap40,
What I recall of the story it's just a difference between left and right crosswind components on that particular model for T.O. & LNDG.
Thank you for your interest.
Happy New Year to you!

I think you'll find the crosswind limitations on Trident 3 were only for take-off. We used to take them to 'wrong' end at Heathrow, wait for a batch- stop the 28L deps & launch the batch of T3 from 10R.
dH used to take a plane back to Hatfield in winter & never actually resolved the problem. One thought was the nosewheel door on the longer fuselage was creating the problem.

Interesting. What was/is the skimming technique?

That's an interesting idea. The NW door that stayed open on the Trident when the gear was down was the port one, so that could account for a lower limit when the x-wind was from the left.

The suggestion that it was related to the boost engine and/or APU position on the T3 is a bit more difficult to understand, given that both were on the centreline, but maybe there's more to that than meets the eye.

I don't understand how that could be the reason, does anyone have an explanation?

I was also wondering what the skimming technique was.

Well sadly we're unlikely ever to be able to put it to the test, but I'd suggest that a 30kt x-wind from port, impinging directly on the Trident's NW barn door would produce rather more of a yawing moment than the same wind from starboard which would hit the NLG leg first. Particularly given that said door hangs at about 30° from the vertical.

Whether that's enough to account for the asymmetry in the x-wind limits, I'll leave for you to judge.

Alternative explanations welcomed, needless to say.

Yes, I've never heard of that.

I am SO impressed that Discorde has kept his manuals - just in case they restore a T3.
There was a slightly different nose-wheel door arrangement on various marks of HS21. After the loss of Turkair Dc10, other aircraft often reported that the Trident doors were not closed. This occurred when say a T1 & T3 were at the hold - we used to have to send a vehicle out to inspect.

On the T1 the right door remained open after nose gear extension. On the T2 and T3 it closed again. Google images of DH121. HNY!

DavidReidUK: The fact that the limits are only different for the take-off case suggests that it is the effect of the operating boost engine that is at play here. (boost always off for landing ) Perhaps the air intake for the boost engine affected the airflow around the fin and rudder?

Hi Meikleour

The boost had intake doors on both sides of the fin, mechanically interconnected, suggesting symmetrical airflow patterns. The APU air inlet was on the left side of the fin and its exhaust gases exited vertically above the centre engine intake. But the T/O limits applied regardless of APU and or boost operation.

I can't remember what the 'skimming technique' was or actually using it and thus far have been unable to find any reference to it in the manuals. [/NERD]

The RB162 had an intake on both sides, and I'm sure those did affect the airflow, but it's not immediately obvious why the effect would be asymmetric necessitating different port/starboard x-wind limits.

Edit: Discorde beat me to it. :O

Skimming technique: a very faint bell rings: it might be the technique of prematurely lifting the nose wheel off the runway prior to rotation proper - on contaminated runways to avoid spray ingestion into the engines? Obviously this procedure would reduce yaw control through loss of nosewheel traction.

If I recall correctly, on the T1C the refuelling panel was in the NLG bay, hence the need for access on the ground, whereas on the T2/T3 (and the T1E, I think) it was moved to one of the MLG bays.

Great thread, by the way, brings back happy memories.

And when there were 20+ Tridents taxying at night - the only one to be recognisable was the T1E, because it had two anti-coll lights on the top of the tail. otherwise we were all guessing!