Hi All,

I'm after some advice regarding wind tunnels as the college that i work at have decided that we need a better one than we have.

My opinion is that the very basic one which we have (designed and manufactured in house) is sufficient as computer based flow testing can be used, however the engineering team believe that we need a proper scaled down wind tunnel in order for students to be able to set it up, log/read data etc etc.

Does anyone have any experience on this type of thing as I really don't want to blow some serious money on this when we could just buy another CNC mill!

Thanks

Olly

Makes no sense unless people have money to burn.

Turn it into a learner exercise to calibrate the tunnel you have - you would have to do this with a new tunnel anyway!

Better to let the learners find out how to use it and to question/correlate the data than just get something new for the sake of it.

If you have to spend budget, have a look at what you could upgrade such as more sensitive load cells, mini rolling road, higher degree of freedom balance, closed-loop variable speed drive for the motive fan etc.

I wish we had a wind tunnel... someone decided sometime ago that engineering was not a growth area

Assuming you are in an engineering department then can I suggest you use some systems engineering principals first -

Draw up a user requirement - what do you want to do with it i.e. teach basic principals of fluid mechanics and demonstrate correlation between experimental data and computational models (usual one is flow around a cylinder or over and simple aerofoil) or is it a design tool for doing both academic and commercial work ?

From the user requirement derive system requirements - how big, how fast, Reynolds numbers, type of measurement etc.

Compare what you have to the requirement and identify deficiencies/improvements and draw up options - do nothing, improve minimal, improve maximal, new buy

Analyse options and come up with a preferred route, from this you can build an investment case.

Once the route is chosen then you can go through the SDR/PDR/CDR design.procurement and evaluation process checking compliance against your requirements as you go through the Verification and Validation assessments. This was you can ensure that what you get is what you want.

Systems Engineering is basically organised common sense.

Not rocket science (or engineering) but having worked in a technology/engineering for quite a while I have observed that techniques used and sold for the benefit of customers are rarely used for internal investments.

This does not necessarily answer the questions but gives a process to come to what is hopefully the right one.

Thanks, i agree it would be better to upgrade what we have if it can be done.

Know what you mean about not investing in Engineering, luckily we were spared but the college just down the road had all its kit binned!

quote:

---

Originally posted by onenastyviper
Makes no sense unless people have money to burn.

Turn it into a learner exercise to calibrate the tunnel you have - you would have to do this with a new tunnel anyway!

Better to let the learners find out how to use it and to question/correlate the data than just get something new for the sake of it.

If you have to spend budget, have a look at what you could upgrade such as more sensitive load cells, mini rolling road, higher degree of freedom balance, closed-loop variable speed drive for the motive fan etc.

I wish we had a wind tunnel... someone decided sometime ago that engineering was not a growth area

---

Thanks Ugg, you are of course 100% correct. Its amazing that the processes that are preached in the classroom often go out of the window as soon as the pressure piles on!

How is your Anglia coming along? Did you get the RX8 transmission fitted?

quote:

---

Originally posted by Ugg10
Assuming you are in an engineering department then can I suggest you use some systems engineering principals first -

Draw up a user requirement - what do you want to do with it i.e. teach basic principals of fluid mechanics and demonstrate correlation between experimental data and computational models (usual one is flow around a cylinder or over and simple aerofoil) or is it a design tool for doing both academic and commercial work ?

From the user requirement derive system requirements - how big, how fast, Reynolds numbers, type of measurement etc.

Compare what you have to the requirement and identify deficiencies/improvements and draw up options - do nothing, improve minimal, improve maximal, new buy

Analyse options and come up with a preferred route, from this you can build an investment case.

Once the route is chosen then you can go through the SDR/PDR/CDR design.procurement and evaluation process checking compliance against your requirements as you go through the Verification and Validation assessments. This was you can ensure that what you get is what you want.

Systems Engineering is basically organised common sense.

Not rocket science (or engineering) but having worked in a technology/engineering for quite a while I have observed that techniques used and sold for the benefit of customers are rarely used for internal investments.

This does not necessarily answer the questions but gives a process to come to what is hopefully the right one.

---

Rx8 box is in mechanically but currently working out the clutch. Have it currently in the original position with very long cable pulling from rear. Does not seen to engage. Guy on turbosport is doing an arm for the original type 9 position so may look into that. Taking an enforced break whilst my garage is being re-built, benefit is I have ordered a mid rise scissor lift to be put in a recess in the floor so will make good use of this sorting out the box.

How's the u8 coming on?

Fantastic, hope you manage to sort the actuation issue soon.

I like the idea of a scissor lift, sounds like you are doing it properly.

U8 progress is ok, got a load of machining done and just waiting for the main bearing caps to be machined as the first batch were awful. Managed to get a refund so Will be making thw next set in evenings at work. Otherwise I'm looking at possibly making the sump from carbon fibre as a friend has a composites company and is up for helping out, although the main reason is that it's too big to machine on our CNC mill at work!

That's about it really, once I have the caps it'll be full steam ahead!

quote:

---

Originally posted by Ugg10
Rx8 box is in mechanically but currently working out the clutch. Have it currently in the original position with very long cable pulling from rear. Does not seen to engage. Guy on turbosport is doing an arm for the original type 9 position so may look into that. Taking an enforced break whilst my garage is being re-built, benefit is I have ordered a mid rise scissor lift to be put in a recess in the floor so will make good use of this sorting out the box.

How's the u8 coming on?

---

Cf sump sounds interesting, I assume it does not contribute to the block stiffness then, may need a guard under it once in the car to protect it.

Been having odd thoughts about using two apriia rsvr v-twin engines sitting side by side in a car, chain drive to an idler shaft then from that to a diff. Would give about 280hp, not the lightest as you have 2 engine, 2 boxes and the shaft/diff but would be easy to engineer, could be pretty compact, similar to a radical rear end but with second shaft. Could use a Mazda mx5 Torsen, rsturbo or atb diff. West wales trikes have some interesting diffs that could be modified. Could add a starter motor reverse. Just need to find something to put it in - MeV rocket or Sylva j17 may be interesting and potentially easy to elongate the engine bay. Think the grass trackers use a set up similar to this.

Do keep us posted on progress.

Sorry for the delay in replying, didn't check my personal emails.

Yes the CF sump idea came from the fact that I've not relied on the sump for stiffness. I'm not 100% convinced but don't think it's going to cost me a lot of time or money to try it so will give it a go.

I remember you mentioning the two v twin idea before and think it would be great. There's far less head scratching involved for a similar performance. I'm not sure if anything I've learned would benefit you but I'd love to see the progress if you do decide to do it.

I'll update my thread as soon as I can, I'm planning on doing a picture of all the parts I now have all laid out nicely because it's getting quite close!

CF Sump??? Therrre be demons in therrre! Ooooh Arrrr.

Tg and resins will be your big hurdles. Not saying it can't be done, I've done it, and even gearbox cases as used in F1 and LM cars. The proper resins are very expensive, and need very special post cure heat treatment.

There's good reason that racecar sumps are metal, even if the thinnest of thin, and some even near to alfoil thin titanium.

Good luck! Been there, had the results and the bent and deformed end products.

Make sure you use a very good oil cooler.

Cheers,
Nev.

Thanks Nev, doesn't sound quite as straightforward as I Thought!

Will be doing some more research before I get in too deep!

Would you mind sharing which resin you used or is it top secret?

Thanks in advance

Olly