Wind Tunnel Models...

[zebedee]

I've always had a bit of a thing about those gorgeous wooden wind tunnel models that manufacturers used to build...

Unfortunatly museums tend to squirrel them away out of sight, which I've always thought is a great pity... Anyway these are a few from Manchester and Southhampton museums which i've managed to take over the years.. I've a few more which i'll post soon.. just need to get permission first...

The first five i have no idea what projects they represent, the last two im pretty sure are a Gnat Mk5 and the Theseus Ambassador...

Zeb

 

[Sentinel Chicken]

The first one is the HS.1034- some sort of variable geometry Mach 2+ interceptor/reconnaissance design.

 

[Jemiba]

No.5 probably is the Fairey Gyrodyne and No.4 could be the scout/attack variant of
the Westland WG.13.

 

[zebedee]

Yep... im pretty sure that 5 is a gyrodyne model... not sure about the WG13 version though... the U/C seems wrong... The model i think is missing a front leg on the right hand side (you can just see the left front leg in the background of the gyrodyne model...) I also got the impression that the wing was asymetric (i could be wrong) so it could be another Gyrodyne version...

Zeb

 

[Mike Pryce]

For Manchester models see also :

http://www.secretprojects.co.uk/forum/index.php/topic,1396.0.html

and for mention of some others:

http://www.secretprojects.co.uk/forum/index.php/topic,1554.0.html

 

[Jemiba]

"..not sure about the WG13 version though"
Yes, you're right, I think. Maybe, the fin and the left wing is just missing,
but the pronounced "hump" is not typical for the attack versions of the
Lynx.
But, btw, the wings of the Fairey Gyrodyne and Jet Gyrodyne actually were
symmetric, the Gyrodyne just had a nacelle carrying the prop on the right wing
and a tank of very similar shape on the left.

 

[elmayerle]

Y'know, this really tempts me to take a few days off sometime and wander down to the wind tunnel at my old alma mater to see if they still have the Boeing TFX wind tunnel model in the basement. As I remember, it came with lots of stores options to check.

I should note that it's been some 35 years since I last saw it and there's no guarantee at all that it's still there. Still, if anyone on this board is currently at Texas A&M, you might want to visit the 8' x 10' wind tunnel out by Easterwood Airport and see if they still have that model and all the goodies that went with it.

 

[hesham]

Hi,


anther sight to HS.1034.

 

[zebedee]

Found this Comet III/IV wind tunnel model on display in the National Museum of Scotland in Edinburgh recently and noticed the engine exhausts tapered into cones. Anyone with a better understanding of give me an idea of what the purpose is?

Zeb

 

[aim9xray]

Fairings for wind tunnel purposes. They chose not to model the intake suction nor the engine discharge (in this particular model) and the fairings produced the least distorted data compared to installing flat blanking plates.

 

[zebedee]

The models intake section has a rounded profile so that makes perfect sense, many thanks!

Zeb

 

[martinbayer]

Fairings for wind tunnel purposes. They chose not to model the intake suction nor the engine discharge (in this particular model) and the fairings produced the least distorted data compared to installing flat blanking plates.

Why not model jet engines simply as hollow cylinders that the air can stream through unimpeded? I'd think that would be much closer to actual physical reality than streamlined fairings and cause even more flow distortion.

 

[aim9xray]

Why not model jet engines simply as hollow cylinders that the air can stream through unimpeded? I'd think that would be much closer to actual physical reality than streamlined fairings and cause even less flow distortion.

Some larger models do, and it is more costly. Also may have to do with whether a smaller (high speed) model can take the loads and stress with scale section thicknesses. Having a model undergo RUD can take a tunnel down for a year or more (it has happened).

A wind tunnel campaign for a modern project may consist of (roughly) 15 models of different sizes (tailored to the tunnels booked) and complexities. (High-speed, low-speed, half-span, flutter, intake, ground plane, wing, etc.)

This rather old AGARD Report (R-19) will provide some insight.


Edit: add report.

 

[zebedee]

Why not model jet engines simply as hollow cylinders that the air can stream through unimpeded? I'd think that would be much closer to actual physical reality than streamlined fairings and cause even less flow distortion.

Surely the mass flow would be different from an engine exhaust, even at scale?

Zeb

 

[aim9xray]

I assume that the downstream flow does not affect the model. I'm at the limit of my knowledge.

 

[martinbayer]

Surely the mass flow would be different from an engine exhaust, even at scale?

Zeb

Of course, since the burnt propellant adds to the mass flow, as would flow velocities. But it would still be *closer* to physical reality than streamlined fairings that force what would be an internal flow *around* the engine instead.