Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“Performance
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum The fastest message board... ever.
Corvair Center 
Pages: Previous12
Current Page: 2 of 2
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 07, 2017 07:45PM

BobV66Vair Wrote:
-------------------------------------------------------
> Kevin, I offer my LM engine as a beta tester for
> the fan! grinning smiley
>
> Seriously, this is a step forward for Corvair fans
> and, we hope, cooling. Is there a theoretical
> maximum airflow through the engine? Wondering if
> there is a point when no fan can flow more air
> through the fins. I know they can handle more than
> the stock fan since Porsche fans on Corvair's flow
> more.
>
> Also, any reason not do make them on a 3D printer?
> Practically any material can be printed now, other
> than aluminum. A super strong polymer might work
> and might be easier to manufacture? Printing
> prices have dropped a lot in the last year and
> should continue to drop. You might be able to sell
> the print program and have people print their own.
> That would probably cause trademark and/or patent
> problems though.

There's some realistic limits on airflow through the engine, but they are
not related to the fan like this. Realize that these types of fans (minus the forward leaning blades) are used every day in industry, at crazy high pressures and crazy high efficiencies.
Real world limitations on airflow through our engines though is a different story. The first limitation is probably significant flow losses at the inlet.
I believe that part of the strange behavior of the stock set-up has something
to do with flow losses related to the actual air path into the inlet. In my stock fan tests that I've done, the predicted pressure lines up perfectly with
GM measured data at 3000 engine rpm and below and I got darned near exactly actual measured pressure as in the GM test's up to 4000 engine rpm, but the predicted pressure starts getting off from actual measured pressure at 4000 engine rpm... the predicted pressure is 1" higher than actual, but does line up below that rpm, and I cant think of anything else to explain that except for air path related flow losses. This issue is something that I do plan to
test THOROUGHLY!!
The next limitation on flow through the engine has to do with "air horsepower", which is a calculated absolute minimum horsepower usage assuming
100% fan efficiency. It is based solely on cfm's and pressure. If the air horsepower get's too high, the actual drive horsepower is going to go through the roof as no fan is 100% efficient.
The last, real hard limit is when no amount of air will keep the head temps from climbing further.... fortunately there is considerable room for improvement in this area.

3d printing.... I tried so many times over the years to get one printed out of metal. ARRGH! at this time, there's no printer big enough to print one out of aluminum, and even if there was, the holes would still have to be machined,
and this can cause some significant balance problems. I looked into printing one from Titanium a few years ago... one company had a printer big enough to do it, unfortunately it was 2000.00 bucks just for them to even look at the model because of demand- you know how that works, the big bucks moves to the front of the line!! anyways, yes, 3d printing is an option for composite's like
ULTEM and others, but is very expensive, and will require re-design... something I'm not willing to do until I know that the fan sizing and performance is up to my expectations.

If you want to be a Beta Tester, talk with Ray about it- I had 2 of these fans made for test purposes, I own both of them, but Ray has the other, as he
has the equipment to do much more rigorous test than I will be able to do.

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 07, 2017 07:58PM

Bob Helt Wrote:
-------------------------------------------------------
> Kevin said:
> should not have a kooky "flat" spot
> at 4k like the Mag fan has,
>
> Bob replies:
> Matt, please explain. None of the Chev engine
> tests show any type of a kooky flat spot in the
> mag fan's air delivery.
> Where did you get your data?
> Bob Helt

I tested this and saw it myself... between 4000 and 4400 rpm the pressure
doesn't smoothly rise like it does at lower rpms. It mostly doesn't change
between those rpms, and then suddenly goes up. Very odd. I have a graph of this
same behavior that someone sent me that was from one of the early Turbo fan tests that showed this same flat spot or whatever it is. I will see if I can find 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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car






Edited 1 time(s). Last edit at 07/07/2017 08:37PM by MattNall.

Options: ReplyQuote
Re: My New Fan!!
Posted by: Mike Stillwell ()
Date: July 08, 2017 03:17AM

Bob, The Porsche fan does not move as much air as the stock fan, but it keeps the belt on at high RPM shifting.

Mike
YS-117

BobV66Vair Wrote:
-------------------------------------------------------
> I know they can handle more than
> the stock fan since Porsche fans on Corvair's flow
> more.
>

Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 08, 2017 07:42AM

cepak Wrote:
-------------------------------------------------------
> So what material was used? Aluminum, steel, ?


This fan was machined from a solid block of 6061 T-6 Aluminum, and was dynamically balanced to be good up to 11000 rpm (!)

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 08, 2017 08:27AM

aircooled6 Wrote:
-------------------------------------------------------
> Cant tell for sure from the picture, but are all
> the vanes equidistant from one another? Wont
> that sound like a siren (or a big vacuum
> cleaner)?
>
> Just wondering, not a criticism.

No, the fins on my fan do not have a unequal spacing like the Mag fan does,
and it is not expected to have "noise" problems like you are thinking about.
It cannot sound like a siren, because for sirens to operate, they have a special chopper/interrupter mechanism that cuts the air flow off momentarily
at regular intervals. Totally different than the continuous air movement into
the fan.
Also, straight bladed radial fans (like the Mag fan) often need the unequal fin spacing because the straight blades are inherently noisy because of the violent changing of direction. The more gentle the direction change at the tips, the quieter the fan is, and the less reason there is for the staggered pitch. The net effect of the smoother exit angle is that the air leaves the fan
much slower than it would if the blades were straight, which is a major reason
for the expected efficiency improvement and reduced noise- the bugger when making a change like this is that the fan needs numerous compensations to assure that the output will be sufficient.... I spent an incredible amount of time on this one issue, and wont really know for sure if I got it right until
it is thoroughly tested!!
I can tell you, a few years ago I had a plastic printed version of this fan tested with an electric motor at roughly 2000 rpm, and the tester stated that it did not appear to sound any louder than the Mag fan did at the same speed
although he remarked that it did sound different!

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: ROD ()
Date: July 08, 2017 10:12AM

Way cool , I wonder how it will sound. I like the porsche vertical fan sound.
Good luck with your road testing ! drinking smiley

Rod Tetrault
El Cajon , CA
65 Corsa Yenko Clone / 65 Corsa EO Creampuff Vert
66 Corsa "JIMISH" Mid engine Turbo LS1 currently 2nd fastest Corvair in the USA
Class 5 Corvair powered Baja
61 Vintage Rampy
Corvair powered Buggy x 3
Enough hidden parts to build a space ship

Options: ReplyQuote
Re: My New Fan!!
Posted by: larry cooper ()
Date: July 08, 2017 05:41PM

nice looking fan - I'm not worried about weight - more about cost ! Price please ?
Larry Cooper

Options: ReplyQuote
Re: My New Fan!!
Posted by: cnicol ()
Date: July 08, 2017 06:04PM

I can't wait to read about your fan's airflow and hp requirements; this is exciting!smileys with beer

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: My New Fan!!
Posted by: aircooled6 ()
Date: July 08, 2017 09:23PM

Kevin,
Thanks for that reply! I learned something, which is always a good thing.

Everett Wilson
North Richland Hills TX
(Now, South of 820!!)
64 Greenbrier 110 with 95 heads/PG

Options: ReplyQuote
Re: My New Fan!!
Posted by: cnicol ()
Date: July 08, 2017 09:57PM

larry cooper Wrote:
-------------------------------------------------------
> nice looking fan - I'm not worried about weight -
> more about cost ! Price please ?
> Larry Cooper

Craig offers:
I'm guessing this is a prototype since it's machined out of a solid block. If the design proves out then a second step might be discovery of a cost-efficient way to produce it. I can think of six different ways to do it and only one is machining it from solid stock.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 08, 2017 11:13PM

larry cooper Wrote:
-------------------------------------------------------
> nice looking fan - I'm not worried about weight -
> more about cost ! Price please ?
> Larry Cooper


Larry- Thanks!! as Craig said, this is a prototype fan, and it was machined from a solid block of aluminum, and it was CRAZY expensive to do it, and I got a great deal on it as it was. I think it is very premature to talk about cost right now, as I don't know for sure how it will perform. If it does what I think it will, I'd rather that other independent tests be done on it by other,
competent individuals to prove that my results aren't "vapor test's", unverifiable by others... in other words, if this turns out to be the Cat's Meow of Corvair fans, it will be worth it to do it the right way and test it as though it was a new GM fan, and have real pressure, volume and hp usage number's so folks can decide for themselves whether it would be worthwhile
for them to buy, as opposed to a untested bling item!

Craig...I'm as excited as all get out to find out what those numbers are!!

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: kdrolt ()
Date: July 09, 2017 10:32AM

FWIW at 4400 rpm, and using 1.58 fan rpm to 1.00 engine rpm, and (guess) 12" OD fan, the tip speed is 111 m/s. That's 0.32 Mach, and that's at the point where compressible flow matters (according to C.F. Taylor, and probably too R.Stone, J.C. Heywood, and J.Mackerle). Intake inlet flow past a valve starts to flatten near 0.4 Mach, so me thinks that's what you are seeing -- the limits of a single stage blower and the flow stagnation effects of air compression.

This link

[turbolab.tamu.edu]

covers the basics (but lots of math!). BTW I love the new fan...

Options: ReplyQuote
Re: My New Fan!!
Posted by: kdrolt ()
Date: July 09, 2017 10:35AM

This one is even better:

[www.tcf.com]

Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 09, 2017 01:33PM

kdrolt- Thanks! and thanks for those links... I'd actually seen and used both of those sources a while back to help me perhaps catch any major bugs before the fans were made... I couldn't find anything way off. About that observed
flat spot at 4000 and above- There's been 2 schools of thought on that for a long time- one is like what you are thinking, that the fans approach their compressibility limits at around that speed- I have some serious doubts about that because the shroud pressure that it happens at is only 10", which is hardly anything. Axial fans like the Porsche fan can hit 23" in race cars, and those types of fans are way worse at flowing against a restriction than any type of centrifugal fan. The other school of thought is that flow losses at the
inlet are causing this. That idea makes a lot of sense to me because of the weird air path. There's actually 3 separate flow loss's on the Corvair fan intake. One is the entrance angle which is darned near 180, the next is the radius of the turn (essentially a zero radius 180) and a 3rd loss for a spigoted entry, because of the protruding lip. All of those losses are proportional to the square of the inlet air speed. At an engine rpm of 4000,
the fan is turning 6320, and flows roughly 1500 cfm. The air coming into the
shroud at that flow rate is something like 70 miles an hour and those flow losses can easily explain the difference in the predicted shroud pressure vs the actual, measured pressure, particularly if the air path changes, even a little. If nothing else, this fan experiment ought to be darned interesting!!!

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: Bob Helt ()
Date: July 09, 2017 02:06PM

Re: My New Fan!!
Posted by: Bob Helt ()
Date: July 07, 2017 06:47PM

Kevin said:
should not have a kooky "flat" spot
at 4k like the Mag fan has,

Bob replies:
Kevin, please explain. None of the Chev engine tests show any type of a kooky flat spot in the mag fan's air delivery. Neither ddid Bob Ballow's data.
Where did you get your data? Please elaborate.
Bob Helt

Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: July 09, 2017 04:20PM

I had previously replied to your question earlier in this thread and in a PM-
I guess you missed that so I will try again here. I have done a number of fan
tests on my 1963 Turbo so as to establish a baseline set of pressure and rpms for my fan and engine, and to see what it would take to replicate GM pressure
vs rpm's for my engine. It turned out to be not to difficult to do- as long as the engine lid was open, the engine was dead cold, and the outdoor air temperature was at 60 degrees, I got 10" at 4000 engine rpm just like GM did.
I've done numerous of these test's at 1k 2k 3k and 4k, all the pressure numbers
agree with GM numbers. Some of my tests went to higher rpms- The flat spot that
I've referred to is that between 4000 and 4400 the pressure hardly moves at all, which is weird, and deviates ALOT from what the fan laws predict over that
short rpm change. I think I saw 10.5" at 4500, but don't remember for sure, it was a single, uncontrolled test. In another of these test's I saw 12.5" at something around 5000, which is again way off low from what should be happening there. A friend had sent me a set of graphs of fan data, and one of those was for a 1963 Turbo, this showed this same flat spot at the same place
as I saw. I said I would look for it, and I did... it turned out to be your data. I don't know where my friend got this from but it is labeled Bob Helt fan data.The one thing that I had totally forgotten, my engine had a Mag fan, the 1963 Turbo fan test obviously did not, so I erred in thinking that it was the fan's fault when it cannot possibly be.

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: February 10, 2018 10:26PM

So as to not hijack the exploding magnesium fan thread anymore, and to update
this thread a little bit, here are some of the intake ideas that I've tested
on my test fixture. The pulley has black tape on it to provide contrast for the
reflective patch for the laser tachometer. The red stuff in in the pulley is clay to create a taper to encourage the air to take a smoother path down through the center of the pulley and bearing. I've done a number of tests with the airflow pulley, gradually upping the flow area. At a little less than 2 square inches worth of opening, it does increase the flow a measureable amount.
At larger openings, without a bell also installed, it loses airflow, but with a bell on, the flow increase is much larger than can be done with a stock pulley and bell mouth. The best bell and airflow pulley combination increased the pressure roughly 24%, and I figured it had increased the flow 11% over a stock configuration pulley and no bell. The best bell by itself was only a 4 to 5% gain. Super impressive for the low rpms that I'm able to test at.

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Attachments:

Options: ReplyQuote
Re: My New Fan!!
Posted by: 4carbcorvair ()
Date: February 11, 2018 05:30AM

Love the look of it. smiling smiley

--------------------------------
Ronnie
Southern Maine.
www.dirigocorvairs.net
66 Corsa Convertible, 140, 4sp.
65 Monza Convertible, 110, PG.




It doesn't leak, it's marking it's territory.

A mirror is a reflection of the miles travelled.

Options: ReplyQuote
Re: My New Fan!!
Posted by: 63turbo ()
Date: May 27, 2018 08:35AM

Update:

The fan appears to be cooling quite nicely now that I've got the timing and fuel dialed in pretty close for the new cam and head work, plus running out all
of the 1 1/2 year old gas. Some interesting observations are that "hot engine
effect" with this fan is an ENTIRELY different animal than I've observed with
any of the hot engine tests that I did with the stock fan... with this fan, when the engine gets warm and the doors full open, the shroud pressure actually
RISES(!) at all measured rpms, appearing to follow a perfect parabola. Not even
close to being the same as with the stock fan, being driven at a much taller fan pulley ratio... the pressure numbers are literally all over the place at the same engine rpms, in some cases the pressures were raised somewhat at 1000 rpm, but all were dropped a bunch at 4k... This pressure lowering effect at high rpm and raising at low rpms is what hot engine effect is supposed to be like, and has the effect of changing the pressure curve so that it is no longer
a parabola, but an exponent somewhat less than 2... for example, for the stock corvair fans the exponent is roughly 1.8, for a Porsche fan it would be 1.95.
My fan is looking like that exponent is exactly 2, which is SAE ideal, although
maybe I just need try this test with the heads hotter, I don't know the conditions that those tests were done at.

Also, the one horsepower usage estimate that I have is that at an engine speed
of 3707, the fan appears to be using 2.45 hp, and applying the fan laws to that
one figure would give 1.3 hp at 3000 engine rpm, and 3.08 at 4000 engine rpm,
and perhaps 5-6 at 5k(!)… pretty incredible, especially when one considers that the mag fan has to be geared down to 1.2:1 to approach those usage numbers, and of course has a massive cooling loss to go along with the ratio change.

I'm hoping to better pin down the hp usage numbers for my fan sometime this
weekend, and post the pressure and volume numbers, but that's what I've got for now.

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

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]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Pages: Previous12
Current Page: 2 of 2


Sorry, only registered users may post in this forum.
This forum powered by Phorum.