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Re: Delrin Fan?
Posted by: jmaechtlen ()
Date: May 11, 2017 11:02PM

Re drag - Remember, the "coefficient" is how much drag per square foot.
Total drag is coefficient frontal area - times speed
and yeah, drag increases as the square of the velocity.

The manufacturers have been learning lots about aerodynamics in the last 50 years - I am sure that most modern cars (90's +) have better coefficients than our beloved Vairs.

Adding a chin spoiler, as far as I know, tends to reduce drag by reducing the amount of air going under the nose of the car. (no I didn't look that up just now, if it's wrong please feel free to correct.)
Anyway, even if it doesn't reduce drag, it increases the effective weight on the front tires at speed. In person, over a beer of cuppa coffee, it might be fun to haggle whether it causes downforce or just reduces lift.

In another (automotive engineering) forum, it was said that automotive aerodynamics is highly un-intuitive!
Cheers!

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Re: Delrin Fan?
Posted by: BobV66Vair ()
Date: May 12, 2017 09:00AM

jmaechtlen Wrote:
-------------------------------------------------------
> Adding a chin spoiler, as far as I know, tends to
> reduce drag by reducing the amount of air going
> under the nose of the car. (no I didn't look that
> up just now, if it's wrong please feel free to
> correct.)
> Anyway, even if it doesn't reduce drag, it
> increases the effective weight on the front tires
> at speed. In person, over a beer of cuppa coffee,
> it might be fun to haggle whether it causes
> downforce or just reduces lift.
>
> In another (automotive engineering) forum, it was
> said that automotive aerodynamics is highly
> un-intuitive!
> Cheers!


Earlier in this thread, I made the same correction and posted a link to expert discussion on the topic.

A spoiler does not increase downforce. It reduces lift. Not semantics, they are different effects. The car is like a wing, flat bottom and curved top. Just like an aircraft wing, that causes lift. By rechanneling air around the car instead of under it, you can reduce the amount of lift. The Corvair chin spoiler really does little in that regard. To make much difference you need to have a lot larger spoiler and shape it better. See photos of earlier posts.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Delrin Fan?
Posted by: 63turbo ()
Date: May 12, 2017 09:32PM

Just to bring this topic back to something fan related,,, heres where the billet fan rumors came from Edit... the link didn't work

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car






Edited 1 time(s). Last edit at 05/12/2017 09:35PM by 63turbo.

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Re: Delrin Fan?
Posted by: 63turbo ()
Date: May 12, 2017 09:42PM

Click on this!!

[1drv.ms]

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Delrin Fan?
Posted by: MattNall ()
Date: May 12, 2017 09:43PM







MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo




Edited 1 time(s). Last edit at 05/12/2017 09:45PM by MattNall.

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Re: Delrin Fan?
Posted by: caroseiii ()
Date: May 14, 2017 09:14PM

Don't drop a sheet metal screw into that fan! You'll never find it!

Crawford

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Re: Delrin Fan?
Posted by: jmaechtlen ()
Date: May 14, 2017 11:01PM

looks gorgeous - has it been tested yet?

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Re: Delrin Fan?
Posted by: tomkeo ()
Date: May 14, 2017 11:18PM

There are a number of things in this discussion I would like to comment on, but I will limit it to just one or two.
PHIL DALY: I first met Ron Cohn at the Pomona drags in 1964--so we go back a long time. I have all the official results for Speed Weeks from 1963 to the early 1980's. The fastest time I have found for Ron was in 1979. It was a qualifing run at 177.9 mph. Phil, I wasn't there so if you have documentation of an 187 mph run, please show it to us. As far as I can tell, 1979 was the last year he ran the blown motor. The 177.9 is still the fastest Corvair/Corvair recorded run. My best was 176.1 mph. Actually, his 1977 run of 155.9 mph with a 2 Liter motor is very impressive too.
CORVAIR AERO: The SAE paper on the E/M sedan showed the Cd at 0.41 at factory ride height. With a 2 deg. negative rake, (front end lower than rear), the Cd dropped to 0.39. Those numbers were the lowest of all American cars at the time, including Studebaker. In my opinion, the Cd for the L/M body is slightly higher, but I have never seen any official test result. Modern sedans like the Accord do have a much lower Cd and the Corvette and Camaro are close to 0.30. Think of it this way. It takes approx. 25% more horsepower for a Corvair to go 175 mph than a Corvette!!
DELRIN FANS: My Devin with the Delrin fan had about 12,000 miles on it when I purchased it in 1971. The fan has been in storage ever since and yet it has stress cracking and warping in various places. Since is weighs only 3 oz. less that a Mag fan, I see no reason to consider Delrin for fan material. What would be beneficial is a Mag fan that moves more air.
Tom Keosababian



Edited 1 time(s). Last edit at 05/14/2017 11:23PM by tomkeo.

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Re: Delrin Fan?
Posted by: Phil Dally ()
Date: May 15, 2017 05:49AM

Tom...when we talked at Ventura I must have misunderstood and heard 187 instead of 177.

Thank you for verifying that Ron is the fastest ever in a stock configuration Corvair.

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Re: Delrin Fan?
Posted by: 63turbo ()
Date: May 15, 2017 07:17PM

jmaechtlen Wrote:
-------------------------------------------------------
> looks gorgeous - has it been tested yet?


Thanks Jay!! There was some preliminary testing done with a printed plastic
prototype a while back. A couple of interesting things that were learned from
the early tests were that, at least at the fan speeds it was tested at (roughly
2k) it did not appear to sound louder than the stock fan did despite not having
a staggered fin pitch like the Mag fan does... it just sounded different. The
other test involved directing airflow onto the fan from different directions
to see how well it could "recover" energy. The tester stated that airflow directed in any direction that was generally towards the fan would cause it to spool right up, but when this same test was tried with the Mag fan, there was
only one direction that would cause it to spin at all!
Because of some practical difficulties with the testing equipment, I decided
to pay to have a couple of real ones machined to do real, full scale testing done. Although not finished, these ARE VERY CLOSE to being done... stay tuned for further details!!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Delrin Fan?
Posted by: BobV66Vair ()
Date: May 15, 2017 10:59PM

Kevin, add me to the list of people interested in this new fan. I have a motor with Ray Sedman that I would love to use as a test bed.

Matt, I love the picture of the turbo bladed fan. That would be sweet if it can achieve better air pressure an not steal more HP.

Isn't modern technology great!

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Delrin Fan?
Posted by: MattNall ()
Date: May 16, 2017 08:24AM

Bob..... that is Kevin's Fan..





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Delrin Fan?
Posted by: coleslaw31 ()
Date: May 16, 2017 08:26AM

Wow that is just plain cool looking!

South Carolina Upstate



68 Monza convertible 140 4spd A/C (coming soon)
66 Corsa coupe 140 4spd

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Re: Delrin Fan?
Posted by: BobV66Vair ()
Date: May 16, 2017 09:08AM

MattNall Wrote:
-------------------------------------------------------
> Bob..... that is Kevin's Fan..


If I could post a picture it would be of Homer Simpson drooling. Kevin, you don't need that darn thing, let me take it off your hands.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Delrin Fan?
Posted by: Paulsgt ()
Date: May 16, 2017 09:16AM

That fan is purdy!

Paul Sergeant
CORSA Central Division Director / CORSA Treasurer <-new title
Lee's Summit, MO
CORSA since 1975
Member – HACOA, Corvair Minnesota, CORSA, Little Indians, POCI



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Re: Delrin Fan?
Posted by: 63turbo ()
Date: May 20, 2017 09:35PM

Thanks everyone for the compliments!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Delrin Fan?
Posted by: v8vair ()
Date: May 21, 2017 06:01AM

I have a Camaro front spoiler on the racer, I dont know if it creates down force or stops lift. The Rear has an 4 inch tail spoiler. Top speed has been just shy of 160. Without the rear spoiler I cant go through turn 9 flat out in high gear,just feels like the rear is dancing, with it feels good.
On the Fan,check out Jeff Rapps (Indy Custom Machine) new plastic fan for the Vertical set ups, it might produce enough pressure for the street. Mike

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Re: Delrin Fan?
Posted by: toytron ()
Date: May 21, 2017 06:41AM

Hey Kevin, that fan looks awesome! I understand what you were talking about with the staggered fan pitch but was I was interested in was how you came up with the number of blades to use and the amount of spiral. Was it trial and error? calculations? A little of both? I'm just interested because I find that stuff interesting. Years age I worked for a toy inventing firm and got to see many of the aspects that went into that sort of stuff. thumbs up

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Re: Delrin Fan?
Posted by: 63turbo ()
Date: May 21, 2017 09:01AM

toytron- I have to tell you, Fluid Mechanic's was one of my best classes in college, but in designing this fan I ended up learning a heck of a lot about fan's and turbo's along the way... I cant believe how many calculations I ended up doing on this fan and how much time I spent on it over the years! Regarding the pitch determination, more fins is better for efficiency and less noise, less fins is lighter but noisier. That being said, successful designs of this type end up with between 10 blades and 16- to narrow this down, I looked at an old turbocharger compressor and it had 14 blades. In my Solidworks model, I tried 14, and it just looked like too many, and 12 didn't look like enough so 13 is what I settled on. There's a number of considerations and calculations involved with the backwards curve and the amount of forward lean, and I'm sorry but I'm going to have to stay quiet about that part for now- It should be sufficient to say that I didn't do it by "winging" it- everything about that fan has a specific reason for it being there, although I have to admit it was gratifying to me that it ended up looking so cool when I was finished with it!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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