Gomez

Hhaha, as soon as I saw Philodox's plane I laughed and thought to myself "It's on topic at least"......Boats are off topic :D

Richard Paul

iTrader: (5)

Yea, that's what I thought(A 10) But the heading said A 160. I know we don't use three digit references except the F 117 (I don't know why that is excepted) Maybe it is a subheading, or a misteak. They use letters for subheadings.

Must be a misteak. It came from my kid, He reads this thread. David, what the hell is a A160.

Richard Paul

iTrader: (5)

I think this was one of the first to use such an engine. Or was it just a strange place to use one. can't remember which. Got that from Turbine_pwr. If anyone cares we can ask him.

Richard Paul

iTrader: (5)

Gomez, boats run turbines too.
Thats all they have in modern ships.
Nuc/subs have turbines.

Gomez

I know, but this is an aeroplane thread Richard. Don't go stuffing it up and upsetting the off topic ****'s by going and bringing boats into it......

Gomez

You haven't got time for this anyway. Back to work.

IcemanVKO

So Richard, you may have beaten me to the punch, but I was thinking, that instead of using a tube, why not drill a tube into the inside of the stator, or basically hollow it out in the middle somewhere, and run the water through that. The stator stage itself becomes the tubing.

I'm not sure if something like this could even be machined, but if it were possible this seems to be the best cooling solution, internally.

Turbine_pwr

RP,

The TF-34 engine is used in the A-10. As you pointed out it's a high bypass turbofan. It has a fan that is connected to a low pressure turbine. But it also has an axial flow high pressure spool that is driven by a high pressure turbine. The combustor is between the hp compressor and the hp turbine. Most of the airflow that goes through the fan... bypasses the core engine and just exits out the nozzle. However, in the process, energy is transfered to that air which results in the generation of thrust. The primary purpose for such an engine is that it yields better fuel consumption than a turbojet because of improvements in propulsive efficiency.

The first use of a high bypass turbi fan was in the C-5A... this then translated into the following commercial aircraft. Today almost all new commercial and business aircraft use high bypass turbofans (benefits - better fuel consumption and reduced noise).

Relative to the cooling discussion: Most gas turbine engines now use turbines that are operating at inlet temperatures that are in some cases above the melting temperature of the metals. To keep these metals cool and allow them to survive... they have very sophisticated cooling schemes and use TBC coatings (thermal barrier coatings). The crazy thing is that we typically use compressor exit air as the coolant (it's typically 800-1400F). However, if you're trying to cool a blade that is seeing 2200-3200F gas temperatures 800-1400F seems cool. Thes blades are typically cast. Newer more sophistcated designs are directionally solidifed or single crystal casting and they have multi-pass internal passages with trip strips and turbulators to increase local heat transfer. This is very cool stuff that operates in very hot temps. Bottomline: Cooled internal passages in stationary and rotating bladerows have been done and can be effective. However, the process ain't cheap. The use of water as a coolant would improve cooling effectiveness and reduce the impact of the fact that you have very limited surface area to transfer heat. However, I'm guessing that it would be difficult to get significant temperature benefits.

However, if you were able to remove as much temperature as each stage addes... you would have created a stepwise equivalent to an isothermal compressor which has dramatic reductions in power required to compress air. I will leave it up to the interested reader to look up isohermal compression in their old thermo text and identify the equations to calculate the work required to deliver 7-10 psi of boost for a RX-8 sized AFSC.

Regards

Richard Paul

iTrader: (5)

Good to hear from you John. Did you ever get my message about Professor Easwaren. Speaking of coatings. There is a thread with your name in the title somewhere. Anywat I'll go again, but let me opost this so you don't go way

Richard Paul

iTrader: (5)

Dr Jay Easwaren was my materials Prof at Western Mich U. He was also my sons. Yes, he was ours, we owned him. Before I get the wise remarks.

Today He owns a company in AZ that overhauls APU's. Since he must have something to do with you company I thought you may know of him. He also has a company in Indy that makes turbine blades.
On his rebuilds he puts some of his coatings on the hot section.

He was a whizz with coatings. I had to machine a lot of things for him over the years. If you met him you'd remember, he is the Walt Disney absent minded professor. All genuis, nuts everywhere else. I once asked him why he wasn't wearing any socks? He said "the stranger I dress the more the kids think I know."

The reason I started to think about him was that someone asked about coatings inside the ren exhaust ports.

Check for that thread and a PM I also sent in this regard.

Gomez

Richard, here's a few pics of the internal cooling passages Turbine Pwr is talking about.

This blade is out of a CFM 56-3 I think...B737 Classic.

Wildcard

Gotta love the aircraft thread!

The A-10 is interesting because it uses a relatively high-bypass ratio turbofan. It is not unique for being a turbofan though. All modern combat aircraft since the mid-1970's have used turbo fan engines. Most of them are low-bypass ratio turbofans, but they are turbofans none the less. You name them - F14, F15, F16, F18, F117, F111. You have to go back to the 1960's to find turbojets.

What's also intersting about the A-10 engine (TF-34) is that the same engine is used in the US Navy S-3 Viking. (pic below)

Hymee

iTrader: (1)

Wildcard,

I need a little edumacation...

I guess the high bypass can easily be distingiushed from the low bypass, by the "big" fan on the front.

So, I understood that turbofan engines make a good percentage of thrust from the fan itself, sorta like a big, hitech multiblade prop. Is that correct? And do the lower bypass engines, such as in your daily driver, produce a much higher percentage of their thrust from the exhaust?

Interesting stuff this

I saw some pretty good pics of a Warthog that had been shot up pretty bad in the gulf a few years ago. I guess it was Desert Storm. But it made it home OK.

Cheers,
Hymee.

twospoons_

The A-10 sure can take a beating. The A-10 I saw from Desert Storm had holes all over. It still flew, but missed the runway a tad when he landed. The pilot then excused his bad landing.
If shrapnel enters the engine, the engine is designed to "spit" it out and restart.

They built the gun (GAU-8A) and then the plane around it.

globi

The problem with machining is that there's always a tool involved that's connected to some machine. So no hollowing it out there unless you have a really really microtiny machine or a trained ant with a micro-chisel.

But you could possibly do some lasersintering if you don't mind paying a fortune:
http://www.warwick.ac.uk/atc/rpt/Tec.../sintering.htm

I guess that's what I was also getting at with that whole cooling thing. More efficient isothermal vs. adiabatic compression. Wouldn't it be nice to have an electrically powered (regenerative braking) water cooled axial flow supercharger on a miller cycle gasoline engine?

But Richard made it clear that watercooling is too costly besides the added complexity. After all most people want more power and not more mileage otherwise they probably would have gotten a Prius in the first place.

mcpheeg

Yeah finally got to the end of this thread.
Just wondering when I get my BEng in Jet Propulsion through the post.
After reading all this I have slightly lost track of the power gains expected from this supercharger project.
Surley we should roughly know what ball park the supercharger will be playing in.
25hp, 50 hp, 100 hp, 125hp, 150hp.
Please say if you think I am turning cynical. But I am ready for FI in the 8 and a lot of companies have my interest in there turbo kits. I really dont want to go down the turbo road. Supercharging the beast looks like the best option.
Have any of you turbo junkies actually ran your 8 with a straight through exhaust system? I mean with the cat out!!! It totally stinks of oil.
And I dont want to be passing these oil filled gases through something that runs as hot as the turbo.
I know it is probably totally safe to do this, just not my cup of tea.
And I know RP doesn't want to say what the supercharger is going to do, I'm not asking for exact figures just the ball park this supercharger will be playing in or round about.
I am hoping for around the 100hp.
But bearing in mind I am from across the vast big pond, the last product I bought from you mericans/canadians did not work for my UK spec 8 you could say that I am slightly sceptical.

Aoshi Shinomori

I wouldn't be worried about this kit not working on your car. Unlike many other forced induction kits, this kit is built for the RX8 alone. It's not a generic blower. Richard is taking every measure to make sure this is perfect for our car. I don't know where exactly you are from, but I don't think anything could be too different so that this blower wouldn't fit correctly. It's pretty damned small. Hope that helped.

Hymee

iTrader: (1)

That is kinda funny you saying that

Hey - I might be able to catch up again in April. I guess it is my turn to get lunch this time!

Cheers,
Hymee.

Richard Paul

iTrader: (5)

Don't forget the drinks mate. :D

Is that how you spell "mate", doesn't look right.

Hymee

iTrader: (1)

Actually, yougotitrightyabastard.

Cheers,
Hymee.

Richard Paul

iTrader: (5)

It's Crankyoldbastard, how many times must I tell you.

Hymee

iTrader: (1)

okyougotitrightagainyacrankyoldbastard

mcpheeg

There has still been no reply to the question of approximate gains this axial supercharger will give.
Roughly please
50hp, 100hp, 150hp???????
:D

rotarygod

The target is a max of 300 fwhp. How close it gets to this goal has yet to be seen.

Richard Paul

iTrader: (5)

Ok, I have said on this thread and others that I don't like to predict HP gaines by boost pressure. I can figure Density ratio which I like bbetter but there are still variables. Judging from what has just transpired with philodox car and the Greedy turbo I have a clue.

Jon is running about what I think is reasonable for the stock fuel system ans compression ratio. However I think I can produce that boost using less power from the engine and it should have more mass. It should be cooler at least not hotter. That is without an IC. I also think it will run better with a drawthrough system.

So what do I think? About 80-85 HP increase. There is more to be had but it costs more and is more work to install. Also if you start getting into higher pressure You'll need better fuel or less compression.

In the end there will be a wall at 300 crank hp. from there it's going to cost. If your the guy who is going to buy FI from whoever tells you he can give you the most power have them show you on someone elses dyno.

There are companys out there right now saying their intake or exhaust will give you 15 or more hp from each one or 30+ hp if buy all there parts. Then you have Racing Beat telling you that their exhaust may give you 3 HP. And they haven't found anyones intake that gave more then 2 with some loosing power. Who should you believe?

If they found any power they would love to sell it to you. When I sold blowers for V-8 engines I told the truth about what the engines made and lost sales o companys that claimed more. But when the magazines tested them my blower more then doubled the increase of the best of the others. Everyone using the same boost.

That's it for tonight