Fiberglass fan?

[widebody911]

I was brainstorming with the guy who makes the RS heater bypass tubes as to what other bits we could build and market. One idea that popped into my head was a fiberglass fan, either the 3.6L stype or the sought-after 275mm unit. I'd want to make something that looked like the old factory fiberglass fans.

Thoughts? I wonder how much of a performance gain - if any - this would give. Is anyone else already making them?

I'll be honest and tell you up front that I have no idea what the flow characteristiics of these fans are.

[masraum]

I wonder about durability. Yes they would last for a 24hours race, but will they last 10-15 years. Still, it would be very cool.

[Embs]

Originally posted by widebody911
I'll be honest and tell you up front that I have no idea what the flow characteristiics of these fans are.

Yes but what would the thrust of these fans be? Would they in fact be able to burst a large trash bag? Hmmm?
(sorry put your puke buckets down, no more eram jokes)

The stock unit is pretty light, I don't think it would be a huge savings. The coolness factor would certainly be there!

[Wil Ferch]

It always seemed rather incredible, that from the very start with the original 2 liter 130 hp engine...right up to later versions that were almost twice the size and maybe close to 3x the hp...the fan design did not change all that much ( sure...pulley ratios changed a bit and there were two different...but still very similar diameters)... all these fans developed about the same air flow ( +/-)...around 1200-1500 liters / sec or minute.
If you'd do a new design, I would like to improve the aero characterisitics, such that we can get close to double the original airflow with about a 1.5 x factor increase in fan hp....it would match today's higher hp ( heat rejection) motors better. I wouldn't just mimic the original design...
---Wil Ferch

[widebody911]

Originally posted by Wil Ferch
If you'd do a new design, I would like to improve the aero characterisitics, such that we can get close to double the original airflow with about a 1.5 x factor increase in fan hp....it would match today's higher hp ( heat rejection) motors better. I wouldn't just mimic the original design...

Unfortunately I don't have the creds to do that sort of work; in the last few boxes of cereal I opened, all I got was a toy. Maybe I should switch to Oat Bran - it worked for Mark

[Embs]

Originally posted by widebody911
it worked for Mark

I can think of some other things that would work for Mark, like various toxic liquids, being bound and gagged etc. etc.


A CF fan to match the CF air tube would be very sweet. Make one and I'll be your first customer.

[Series900]

Cut the blades of the stock fan, and , nevermind, handlayup of blades will never work. It would have to be an injection molded piece. think about the balancing needed. back to sniffin styrene....

[RickM]

What are the ultra advanced fan/props in today's jets made out of?

I don't think CF or FG would be viable materials to use.

[Leland Pate]

The fan blades are too small.
What you need to do is to relocate the alternator to a more conventional location (Like the AC). Then you can have a fan that doesn't require that huge alt. housing and could have more blade surface.
I wonder if I can get a hold of a primary compressor blade fan from a small Pratt-Whitney or something... yeah...yeah...thats the ticket!

[surflvr911sc]

I agree that the fan is already light and not really where I would want to risk strength or durability. There a lot of 30+ old fans out there that are still good as new. It is also an efficient design, not unlike turbo jet/fan compressor blades, the blades in the engine not the fan you see from the front.

Thom, maybe CF engine tin? I bet you could loose a few pounds there and you would never worry about rusted tin again. I’ll see what else I can think of too.

[widebody911]

Originally posted by surflvr911sc
Thom, maybe CF engine tin? I bet you could loose a few pounds there and you would never worry about rusted tin again. I’ll see what else I can think of too.

There's a couple places doing that already, as well as CF dashes.

Other thoughts I had was a lightweight version of the little cover under the fuel pump/steering rack, but I think most people just throw it away and run without.

[masraum]

Isn't there already a cf engine tin?

The fan can be done, the old racecars used f/g fans.

[Jamie79SC]

The alternator is not really that much in the way. Remember that it is the outermost part of the blade that is moving the fastest/furthest and doing the bulk of the work. Look at some of the air racers of the early thirties. Barely 15% of the blade radius projects beyond the cowling. The "surface area" of the propeller disk projecting beyond the cowling, however, is much greater than 15% as is the thrust generated by that part of the blade.

I'm sure Island 911 will chip in with some formulas.

[RickM]

Regarding Jet fans:

"Typically titanium, aluminum and stainless steel have been used in the fan blades. Titanium is currently favored because of its light weight, corrosion resistance and good high cycle fatigue properties. Future planes may use fans with polymer (plastic) matrix or ceramic matrix composite blades."
From http://www.madsci.org/posts/archives/mar99/921908947.Eg.r.html

[jhelgesen]

RC airplane props are molded out of glass filled nylon, and some are CF. Airfoils get pretty complex and they handle 20k rpm and up sometimes. I'd say it could be done, but it wouldn't be cheap.

I like the idea of relocating the alt and using a smaller already existing fan, good use for an "eRam"

[chuckw951]

How about converting to water cooled heads and mounting an electric fan in the rear?

[RickM]

Quote: "How about converting to water cooled heads and mounting an electric fan in the rear?"

You do that and I'll give you the 996 decal.

[widebody911]

Originally posted by RickM
Quote: "How about converting to water cooled heads and mounting an electric fan in the rear?"

You do that and I'll give you the 996 decal.

How about a 959 decal instead?

[Series900]

masuram sees old F/G fans

these would have been built in 2 or more piece pressure molds, not hand layup. If Thom wants some bling bling, you could cover the stock blades with CF and layer up some resin on top and sand , clear and buff, BLING BLING...

[RickM]

Those 959 decals are too expensive. ;-)