Jon Ison
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| posted on 15/4/10 at 07:30 PM |
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Very much WIP
But will this get enough cold air in, dont panic its having a coat of fresh paint once bonnets complete.
 
Description
 
Rescued attachment aa1.jpg
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rsmith95uk
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| posted on 15/4/10 at 07:34 PM |
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Yep - should keep the pedal box nice & cool 
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Cousin Cleotis
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| posted on 15/4/10 at 07:35 PM |
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Looks good, but not really the correct way to use that particular air intake, from what i have read in a couple of books, never used one myself. Its
called a "NACA duct" for anyone wanting to research.
Paul
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MakeEverything
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| posted on 15/4/10 at 08:02 PM |
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quote:
Originally posted by Cousin Cleotis
not really the correct way to use that particular air intake
So? If it works, and its safe, then its all good id say.
Looks ok to me. Good work cutting it in so well. 
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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Cousin Cleotis
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| posted on 15/4/10 at 08:15 PM |
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quote:
Originally posted by MakeEverything
So?
A different design or placement might work better, thats all........... My comment didnt really need clarifying, pretty basic use of the English
language, or so i thought.
Like i said, looks good, good compromise between form and function?
Paul
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MakeEverything
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| posted on 15/4/10 at 08:23 PM |
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quote:
Originally posted by Cousin Cleotis
My comment didnt really need clarifying, pretty basic use of the English language, or so i thought.
Paul
Someone's tired!
Not quite sure why you say not correct though?
[Edited on 15-4-10 by MakeEverything]
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 15/4/10 at 08:37 PM |
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Cousin Clitoris,
Yes, youre right. Ferrari got it wrong too.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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Confused but excited.
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| posted on 15/4/10 at 08:37 PM |
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quote:
Originally posted by Cousin Cleotis
Looks good, but not really the correct way to use that particular air intake, from what i have read in a couple of books, never used one myself. Its
called a "NACA duct" for anyone wanting to research.
Paul
For those that don't want to do the research, it could possibly be called a 'KNACKERED duct'. 
Personally I think it looks 
Tell them about the bent treacle edges!
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Cousin Cleotis
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| posted on 15/4/10 at 08:42 PM |
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I did not comment to put down someone's work, it looks like a job well done. but the question was, will this get enough cold air? This is a
technical forum?
NACA ducts have to be made to a strict set of dimensions and positioned on panels as flat as possible and so that the air flows over them and not into
them, the air will flow into them because of the shape. It looks like a NACA duct but will not function as one.
A different design intake may work better.
MakeEverything, I can assure you I'm not tired my bed time is not until 10pm. I don't have a great way with words and often may seam short
and sharp, that's just the way I write. The "So?" and "Someone's tired!" comment make me feel a little attacked,
for no just reason that I can see. I thought this thread was started to discuss the air intake on this discussion forum.
Paul
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Cousin Cleotis
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| posted on 15/4/10 at 08:45 PM |
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quote:
Originally posted by MakeEverything
Cousin Clitoris,
Yes, youre right. Ferrari got it wrong too.
Did they? Positioned on flat panels? Yes. Air flows over the duct? Yes. The hole in the back of the duct is square not round? Yes.
Locost NACA Duct, Positioned on flat panels? No. Air flows over the duct? No. The hole in the back of the duct is square not round? No.
Paul
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MakeEverything
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| posted on 15/4/10 at 08:46 PM |
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quote:
Originally posted by Cousin Cleotis
MakeEverything, I can assure you I'm not tired my bed time is not until 10pm. I don't have a great way with words and often may seam short
and sharp, that's just the way I write. The "So?" and "Someone's tired!" comment make me feel a little attacked,
for no just reason that I can see. I thought this thread was started to discuss the air intake on this discussion forum.
Paul
Ok, ok, Sorry Paul. I wasnt attacking, rather thought i was defending what seemed like a snipe! Truce!!
The NACA duct or NACA scoop is a common form of low-drag intake design, originally developed by the National Advisory Committee for Aeronautics (the
precursor to NASA) in 1945. When properly implemented, it allows air to be drawn into an internal duct, often for cooling purposes, with a minimal
disturbance to the flow. The design was originally called a "submerged inlet," since it consists of a shallow ramp with curved walls
recessed into the exposed surface of a streamlined body, such as an aircraft. It is especially favored in racing car design.
Prior submerged inlet experiments showed poor pressure recovery due to the slow-moving boundary layer entering the intake. This design is believed to
work because the combination of the gentle ramp angle and the curvature profile of the walls creates counter-rotating vortices which deflect the
boundary layer away from the intake and draws in the faster moving air, while avoiding the form drag and flow separation that can occur with
protruding inlet designs. This type of flush inlet generally cannot achieve the larger ram pressures and flow volumes of an external design, and so is
rarely used for the jet engine intake application for which it was originally designed, (the North American YF-93 and Short Sherpa being exceptions.)
It is, however, common for engine and ventilation intakes.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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Jon Ison
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| posted on 15/4/10 at 08:55 PM |
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oooerrrrrrrr.
I only cut an hole.
The way I see it is like this, its a 7, not a lot of bodywork to play with and as its hand made by moi none of them are gonna flat so.......
Do I leave the air intake under the bonnet to suck in hot air that's flowing through the rad or cut a hole and let it pull a bit of cold in,
I'm pretty sure 4 pistons spinning at 11000rpm will suck hard enough ? Oh and with a bit if gobo n paint I think it will look ok to.
What is the best way to feed cool air directly to a airbox, particularly given the tight bodywork restraints of a 7 clone ?
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boggle
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| posted on 15/4/10 at 09:09 PM |
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looks good and i think it will work well as a ram air feed......
just because you are a character, doesnt mean you have character....
for all your bespoke parts, ali welding, waterjet, laser, folding, turning, milling, composite work, spraying, anodising and cad drawing....
u2u me for details
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Jon Ison
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| posted on 15/4/10 at 09:17 PM |
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Don't worry, Ive come up with a better (light hearted) solution, just need to cut a hole in back to feed air box, of and sit on a big cushion to
see over it............
Serious question to those in the know, what is the best way to get a cool air feed into a forward facing air box like the set up I have ?
 
Rescued attachment bin.jpg
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Cousin Cleotis
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| posted on 15/4/10 at 09:27 PM |
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quote:
Originally posted by Jon Ison
What is the best way to feed cool air directly to a airbox, particularly given the tight bodywork restraints of a 7 clone ?
I think NACA ducts do look good, but would be difficult to get to work right, plan on visiting a wind tunnel? They are designed for low drag intakes,
not for ram air, as fitted to most motorbikes.
Getting the shape right is easy, how big to make it? no idea. Where to put it? Probably on the front of the bonnet, Its flat and air would flow over
it.
I would probably leave the intake where it is but change the shape for better ram air design. Dont know what shape though.
Paul
[Edited on 15/4/10 by Cousin Cleotis]
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owelly
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| posted on 15/4/10 at 09:32 PM |
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To know if the duct will work as intended, you need to put some wool 'tell tails" in the duct at the mouth and a bit further in. Try
shrouding the duct in various places with modelling clay (plasticine) to disrupt the air flow to see if that make it work better. Roundy fronted cars
do strange things to air flow and we all know that air passing over a panel will create a lower pressure than that of the still air under it.
That's why your hair gets sucked up through a sunroof (if you have hair, and a sunroof that is open). I was suprised to find that , at above
30ish MPH a flappy sticker was getting sucked from the front edge of my bonnet, forwards and down into the grill. When I made the bonnet a tighter fit
on the front edge, the sticker would blow up and backwards as you'd imagine it should do.
[Edited on 15/4/10 by owelly]
http://www.ppcmag.co.uk
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brianthemagical
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| posted on 15/4/10 at 09:44 PM |
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On a car with drag of a seven, a duct is highly negligible.
For the best ram air effect, and thus the most effective intake, a vertical hole incident to the flow is best.
If you want it on a surface ~parallel to the flow, then a scoop type duct will work fine. A NACA duct is for use when you need it to be efficient,
such that it doesn't affect the boundary layer, or cause laminar flow bubbles and such where they are not needed.
A 'scoop' design will produce the highest 'inlet effect', much like a heavily cambered wing would produce a higher Cl, but
where efficiency is concerned neither of very effective.
As for this situation, if it were a pure NACA duct then it may not be as good as it could be, as such the design being similar to a NACA duct does add
some complexity and needles work. Saying that, it's already been done, so there's no point changing it but if it were to be done again a
simple smoothed and highly radiied hole would be best.
[Edited on 15/4/10 by brianthemagical]
[Edited on 15/4/10 by brianthemagical]
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bi22le
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| posted on 15/4/10 at 10:32 PM |
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i agree with most that has been said but i think an important point is being missed. This naca thing is not being used as a duct but a cold air feed.
There is a massive vacuum being created by the engine voiding the original design. It does however allow the engine to suck premium fast flowing
air.
I think its tidy and for a mod that is nice looking and functional, its bob on!
Regarding the supply to the box, i think a flex hose straight to the air box will be fine. Your building a fun car not a cutting edge race car!
Hmmm does look tidy though.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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hicost blade
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| posted on 15/4/10 at 10:58 PM |
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I think it looks neat, it will give the more of a ram air effect unlike a proper NACA duct although I think it will still be effective. I have a
similar ReVerie 100mm 'NACA' duct and I intend to do exactly the same thing.
If I was you I would look at a slightly bigger air box
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matt_gsxr
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| posted on 15/4/10 at 11:11 PM |
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These ducts are well proven in RGB and work (probably mostly due to direct cool air feed). In this implementation it looks good and should function
well.
Regarding ram air, you won't go fast enough for any real significant effects, this has been mentioned a few times before. So there is little
point optimising it for ram-air.
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marmot0
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| posted on 16/4/10 at 03:46 AM |
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works on my car
 
rgb front
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Ivan
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| posted on 16/4/10 at 06:16 AM |
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I think it will work just fine - just one thing - the corrugated air pipe has very poor flow charecterisitics causing major turbulance - much better
to go for a smooth bore pipe - that will more than make up for any "inefficiencies" in the utilisation of the NACA form
Also don't forget the fact that the air is entering a negative presure in your duct will change the dynamics of the NACA type duct so be content
that it will work well - certainly much better than no duct at all.
Oh - and it looks very cool.
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Toprivetguns
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| posted on 16/4/10 at 07:55 AM |
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I think it looks great. Hard work and with a design set it mind. Well done mate !
Only drive as fast as your angel can fly... !
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D Beddows
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| posted on 16/4/10 at 08:29 AM |
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plus it looks a bit like the 'Time Tunnel' which has to be a good thing
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gingerprince
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| posted on 16/4/10 at 09:08 AM |
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Aren't knacker ducts just for keeping your nutsack cool?
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