There's a website that Tom Downey posted about on the old yahoo-170 club, somebody claims that he'll soon be producing the old Aeromatic propellers again. Not controllable,but automatic-variable-pitch. Guess I'll believe it when I see it. I don't think he ever specified the price either. that'll probably be unbelievable as well!
Eric
hotrod 0300, 0145, higher hp,
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Hey, guys. Think about this. An engine mfr. designs an engine and sells it to an airframe mfr. who demands performance guarantees. Airframe demands 145 hp at 2700 rpm. So the Engine people make a design that provides for the worst engine at the end of it's TBO will still make 145 hp at 2700 rpm that the type certificate requires and that the Airframe mfr is guaranteed.
What do you suppose the average engine off the assy line makes in a dyno test? 157 hp is only a 1.08% "improvement" over the design 145 hp. I'd suggest that in this case "improvement" is analagous to "normal".
Remember,...the 145 hp is a minimum guarantee ...not a maximum. The engine maker is not going to produce a design that will result in a failure-to-perform lawsuit from Airframe ...or a liability lawsuit from the end user. All these engines, when properly assembled, will slightly exceed 145 hp in a dyno test.
Porting and polishing and "flow checking" and "blueprinting" and balancing is nothing that major, long-time engine manufacturers don't know all about. The inherent design of the engine addresses all these issues, and the return on investment for internal voodoo detailing of an engine is a very real waste of money.
I know of a Offenhauser engine builder (classic Indy 500 cars) who deliberately "roughed-up" the intakes of those engines and cylinder intake valve ports to improve fuel vapor agitation because it improved fuel burn according to the dynometer. His process was so secret that competitors tried to discover it by getting their spys hired by him in the assembly shop. He never let anyone see his secret. After he died, his son personally told me that he did the work with an ordinary sand-blaster!
Is somebody trying to make a buck on the process going to convince me that he is so much smarter than the designer/mfr of that engine and will make it do something it was not designed to do? Not likely.
What do you suppose the average engine off the assy line makes in a dyno test? 157 hp is only a 1.08% "improvement" over the design 145 hp. I'd suggest that in this case "improvement" is analagous to "normal".
Remember,...the 145 hp is a minimum guarantee ...not a maximum. The engine maker is not going to produce a design that will result in a failure-to-perform lawsuit from Airframe ...or a liability lawsuit from the end user. All these engines, when properly assembled, will slightly exceed 145 hp in a dyno test.
Porting and polishing and "flow checking" and "blueprinting" and balancing is nothing that major, long-time engine manufacturers don't know all about. The inherent design of the engine addresses all these issues, and the return on investment for internal voodoo detailing of an engine is a very real waste of money.
I know of a Offenhauser engine builder (classic Indy 500 cars) who deliberately "roughed-up" the intakes of those engines and cylinder intake valve ports to improve fuel vapor agitation because it improved fuel burn according to the dynometer. His process was so secret that competitors tried to discover it by getting their spys hired by him in the assembly shop. He never let anyone see his secret. After he died, his son personally told me that he did the work with an ordinary sand-blaster!
Is somebody trying to make a buck on the process going to convince me that he is so much smarter than the designer/mfr of that engine and will make it do something it was not designed to do? Not likely.
George, 145 bhp to 157 bhp is an 8% increase not a 1.08% increase. I will have to disagree on your opinion on port polishing and flow balancing. It has been going on for years with people who build high performance engines, and I can assure you it is not "voodoo". True, this procedure by it self does not provide a huge increase but it does help. The manufactures do not do it because of the added cost. The secret to increaseing performance is usually a bunch of small improvements to the whole system - better exhaust flow, better carburation, better ignition, etc. Unfortunatly, most of this is not legal for certified aircraft, SOMETIMES with good reason. The old air cold Volkswagen engines are frequently pushed to two, three, even six times there original power. I think even the old O-300 could modified with at least an additional 25% without a decrease in reliability.
All I can say is numerous dyno test prove this statement wrong. I am not talking about making it a high performance engine, just a more effiecient engine. This is a 50 year old design, and engine technology has come a long way since then in improving volumetric effiecienciy in engines ( as well as other improvements).blueldr wrote:Port polishing and flow balancing is a total waste of time on an engine with a seven to one compression ratio and a RPM limit of 2700. This is a far cry from a "High Performance" engine.
Sorry, that was a typo,...what my calculation showed was a 108% of 145 hp,...which is indeed an 8% increase. But the rest of my message is correct....all these engines are likely to test greater than 145 hp on a dynometer at 2700 rpm by design. The 145 is a guaranteed minimum hp and it's not disqualifying to exceed that by a small margin. 8% is hardly worth spending another $1K on, in my opinion, especially since it likely is present on all the rest of the engines in the fleet that did not have all that voodoo done to them.lowNslow wrote:George, 145 bhp to 157 bhp is an 8% increase not a 1.08% increase. I will have to disagree on your opinion on port polishing and flow balancing. It has been going on for years with people who build high performance engines, and I can assure you it is not "voodoo". True, this procedure by it self does not provide a huge increase but it does help. The manufactures do not do it because of the added cost. The secret to increaseing performance is usually a bunch of small improvements to the whole system - better exhaust flow, better carburation, better ignition, etc. Unfortunatly, most of this is not legal for certified aircraft, SOMETIMES with good reason. The old air cold Volkswagen engines are frequently pushed to two, three, even six times there original power. I think even the old O-300 could modified with at least an additional 25% without a decrease in reliability.
This is an interesting topic. George,and others, everyone I've spoken to over the years say that a factory engine will Not produce its rated Hp unless it is blueprinted, matched, flowed etc. They say(I know, there's that THEY word) that an 0-200 will get about 90 hp an 0-320 about 140hp etc. I find it hard to believe an 0-300 developes 145hp. On paper, when designed, based on displacement, stroke and RPM it may theoritically get 145 hp but the manufacturing process will take a toll and on the line I doubt you are getting that hp. Furthermore, you are not getting 2700 rpm on T.O. roll. But I'm sure you know all this. The point remains that folks are spending 40,000 dollars on engine conversions to get a 20% improvement, and the question remains can I get 10 or maybe 15% without spending 40,000 bucks? Due to regulation, this industry has seen some very slow improvements. I understand there are other factors like safety and reliability that are far more critical in this industry but I also believe that we could improve on this engine without impacting those issues, if done in moderation. As you know, these things run on the exponential curve, ie a 10hp increase costs the manuf 50% and a further 5% increase in hp costs a 100% increase in costs etc. and therein lies the reason they are not more efficient. You and I could not afford the engine. Look what a F1 race engine cost.
Like many of you I have built lots of VW engines and I can tell you speed cost money and the faster you go the shorter the engine life, but I can also tell you that I can get an extra 10 to 15% with no sacrifice in longevity or reliability. Part of the reason I can do it is because my labor is free Vs the factory and I will spend extra for aftermarket parts. George I know you have built these engines and I'm pretty sure you would agree with this.
This was not supposed to be a tirade, rather just another opinion. So, if we use a unisyn ignition system, C-85 pistons to raise the compression just a little, say to 8 Vs 7, an Eilson throttle body, better exhaust, ballanced, flowed, matched etc. I think you might see 155Hp. But remember your starting point is probably 135 hp not 145 so yea thats a big leap. I am building a Hatz biplane, very slowly, but I hope to build the 0-200 engine and, since I have access to a Dyno, I'm hoping to run a full scale set of tests to see if these things really work, one change at a time and on the dyno each time. It will take a lot of effort but I think it will be good for the collective group and body of knowledge.
But all that said we are still left with the regulation issues. None-the-less it is fun to ponder......
Like many of you I have built lots of VW engines and I can tell you speed cost money and the faster you go the shorter the engine life, but I can also tell you that I can get an extra 10 to 15% with no sacrifice in longevity or reliability. Part of the reason I can do it is because my labor is free Vs the factory and I will spend extra for aftermarket parts. George I know you have built these engines and I'm pretty sure you would agree with this.
This was not supposed to be a tirade, rather just another opinion. So, if we use a unisyn ignition system, C-85 pistons to raise the compression just a little, say to 8 Vs 7, an Eilson throttle body, better exhaust, ballanced, flowed, matched etc. I think you might see 155Hp. But remember your starting point is probably 135 hp not 145 so yea thats a big leap. I am building a Hatz biplane, very slowly, but I hope to build the 0-200 engine and, since I have access to a Dyno, I'm hoping to run a full scale set of tests to see if these things really work, one change at a time and on the dyno each time. It will take a lot of effort but I think it will be good for the collective group and body of knowledge.
But all that said we are still left with the regulation issues. None-the-less it is fun to ponder......
In a nutshell, Bill, here's what I believe is true. The O-200 only gets rated hp at rated rpm. The O-300 only gets rated hp (145) at rated rpm (2700.) The reason Cessna 150 owners don't get 100 hp and Cessna 170 owners don't get 145 hp at takeoff/climb is because they are using a fixed pitch prop that prevents them from obtaining rated rpm. It's really just that simple.
If you want to get 145 hp out of an O-300, then you can certainly do it at some lower rpm by increasing compressions, or increasing displacement, etc. (but the cheapest way would be to simply advance the mag timing a couple of degrees) or some other costly (if you do it legally) or illegal means (to do it cheaply). Reliability (over the plain O-300) will be affected either way. The only way to make the increase and not diminish reliability would be to add strength (and therefore weight) to the rest of the engine comparable to the increased performance asked of the cylinders. All things in aviation are some sort of compromise. You never get anything for free.
If you want to get 145 hp out of an O-300, then you can certainly do it at some lower rpm by increasing compressions, or increasing displacement, etc. (but the cheapest way would be to simply advance the mag timing a couple of degrees) or some other costly (if you do it legally) or illegal means (to do it cheaply). Reliability (over the plain O-300) will be affected either way. The only way to make the increase and not diminish reliability would be to add strength (and therefore weight) to the rest of the engine comparable to the increased performance asked of the cylinders. All things in aviation are some sort of compromise. You never get anything for free.
The one real problem with these older engines is in valve flow and exhaust systems design. Increasing timing, compression etc. will add power, but at the expense of extra heat. By increasing the breathing capability of the engine you increase engine efficiency, power, and heat dissipation. I know this does not add huge amounts of power, but I'll take what I can get. When dealing with technology this old, not all improvements are necessarily a tradeoff. Saying that the manufacture thought of all this when they produced may be true, but that was also with 50 year old technology.
George and others
You are right that you can't get the Hp unless you get the RPM and the cheapest way to do that is with a different prop but that will be a compromise as you said. And thats the whole story of aviation, its one big Compromise. You are also right that if you increase the Hp of an 0-300 you may compromise its life.
Let there be no doubt, I make my living flying so I can not afford to have my C-170 anything but 100% legal. Every I and every T dotted and crossed; however, it is fun to speculate and if I ever finish the homebuilt, in the experimental catigory, it will be fun to play with the engine a little. Not too much but....
Bill
You are right that you can't get the Hp unless you get the RPM and the cheapest way to do that is with a different prop but that will be a compromise as you said. And thats the whole story of aviation, its one big Compromise. You are also right that if you increase the Hp of an 0-300 you may compromise its life.
Let there be no doubt, I make my living flying so I can not afford to have my C-170 anything but 100% legal. Every I and every T dotted and crossed; however, it is fun to speculate and if I ever finish the homebuilt, in the experimental catigory, it will be fun to play with the engine a little. Not too much but....
Bill
There is nothing new in technology with regard to this core engine. Peripherals, yes, such as ignition systems, and fuel systems. There are electronic fuel injection systems and solid state ignition systems with variable timing, etc. And Unison has begun to produce such ignition systems for aviation use. But not in the core engine such as this thread has been discussing. Pistons, valves, etc. are all pretty much like they were back 50-70 years ago. True, in the automotive world there are now hemispherical heads, multiple valves (so-called multi-port), and dual cams etc etc...but none of those types of mods have been discussed (or even seem possible) in this message thread.lowNslow wrote:The one real problem with these older engines is in valve flow and exhaust systems design. Increasing timing, compression etc. will add power, but at the expense of extra heat. By increasing the breathing capability of the engine you increase engine efficiency, power, and heat dissipation. I know this does not add huge amounts of power, but I'll take what I can get. When dealing with technology this old, not all improvements are necessarily a tradeoff. Saying that the manufacture thought of all this when they produced may be true, but that was also with 50 year old technology.
You want to do something spectacular with this engine? Try a variable pitch prop and an aftermarket turbocharger in conjunction with fuel injection. Those could be certificated without too much trouble. But it still won't be cheap. I believe that paying anything extra to a shop who makes performance claims on balancing and blueprinting and polishing etc, on these O-300's or any normally aspirated aero-engine is proof that shop has a good pitch man.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
I thought I just about had my top secret high performance mods for the trusty C-145 all worked out,and would soon be able to offer a kit for sale. I could tell by this forum that there was a ready market for the right stuff. But I had a little trouble today--when I hit the nitrous oxide switch for a short-field takeoff,I blew the number 2,4,& 6 cylinders right off the engine! Found two of them in a ditch behind the VASI lights,still looking for the third one.
Oh well,back to the drawing board........
Eric
Oh well,back to the drawing board........
Eric
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Joe Dickey
- Posts: 18
- Joined: Sun Dec 01, 2002 1:07 pm
Easy does it!!
Eric,
Perhaps you're playing too rough with the jugs. I'm told they prefer a soft tender touch, wine, soft music and a hot tub also helps!!
Perhaps you're playing too rough with the jugs. I'm told they prefer a soft tender touch, wine, soft music and a hot tub also helps!!
Joe Dickey
C 170
N1948A
C 170
N1948A