Vampire Trim Tabs

[BAZZA BOEING]

Hello, Today I was looking at two Vampires that had dropped into Christchurch on their way north and while they were being refuelled I was looking at the Elevator and noticed that the Trim tab on the elevator was offset quite a bit to the left and was wondering if anyone on this forum knows why this would be as I could not think of a reason why.

Regards Barry

[Arm out the window]

Here's a wild guess, anyhow.
If it was in the middle, it would get the turbulent airflow off the fuselage pod, particularly at high AOA.
Being out to one side would give it cleaner flow and therefore better effectiveness and consistency of operation. (??)

See, if I don't know, I can make it up with the best of them!

[Sunfish]

Southern Hemisphere Vampires have it offset left. Northern hemisphere Vampires have it offset to the right as a simple mechanical counter to coriolis force.

[Ultralights]

See, if I don't know, I can make it up with the best of them!

can you make up one for conventional design aircraft? as quite a few i have sen have the trim tab offset or on 1 elevator only

[18greens]

Isn't it just for simlicity of attatching the linkage. The contol wire must come down the booms and its easier to offset it to reduce the length of the linkage.(Perhaps)

[Arm out the window]

Same idea with a full-span elevator, move it to the side to avoid dirty airflow from the fuselage.
With split elevators (ie one each side of the fuselage), cheaper and easier to set up just one tab, and the slight rolling moment caused by trim changes not enough to worry about. Sound fair?

I like Sunfish's concept though.:ok:

[Fragnasty]

It is offset to keep it clear of the jet efflux (exhaust). The designer tossed a coin, it came up heads, and he chose left over right.

[TeamTerminal]

My turn;
Yes it was offset to alleviate potential tubulent flow from the pod @ high AOA.
Yes it was offset to keep it clear of jet efflux to alleviate the effect changes in power settings would have.
Yes it was offset to allow a simplified control mechanism down one boom.
The left however was selected over the right due to the symbiotic effect the slight rolling moment had on the gyroscopic effect induced by the large centrifigul compressors on both the NENE & Goblin engine variants during pitch changes.
The Coriolis effects although minor were compensated for by adjusting the magnetic fields using the flux valve. This was usually done on the compass swing when carrying out the southern hemisphere compensation bias on the compasses.
The latter of course was not required on Vampires fitted with Australian built NENE engines.
Doing my apprenticeship on these aircraft I discovered one of the above statements is not true. This would of course be apparent to the instructor seated in the two seat variant.
Next.
TT

[Fragnasty]

What bollocks. Anyone worth his salt knows it's all due to interference between the trim tab and the location of the thronomister.

[69s]

Why did the Vampire have a wide and deep groove molded in the nosewheel tire?:ok:

[stevef]

I've a feeling it was to reduce the chances of nosewheel shimmy. Could be mistaken, though. The pattern wasn't peculiar the Vampire/Venom, I've seen it on the Dove, Heron and also on the Mosquito tailwheel.

[69s]

Yup.......:p