Ernie:

Thank you for your post.

If the position of the forum has changed concerning personal atacks, let me say that it is for the best. Maybe a few slip through as in the one two mesages above. Maybe it should be obvious that members worthy of discussion use their own names. For that I thank you personally for doing so.

Now, on to a scientific and worthy discussion. You mentioned that you have some reservations about using some mixture choices. Since you are a man of science as an engineer, I would be most interested in your views and opinions which are able to be backed by any science or research of which I may be unaware. Let's look at this from a scientific point of view. I have a lot of data to share, if you are interested.

Just what concerns you about having more air than stoichiometric in a mixture charge? Let's take them one at a time and discuss the science as it is currently appreciated.

This is getting out of hand
 

You know, I come here because I want to learn good things about skymasters from those who drive them. I currently do not have a medical though I am active in aviation. When (and if) the day comes I will be trotting over to the Skymaster Store (Commodore Aerospace) and see if Don can fix me up. I love this airplane. Yes and Don even knows the one I want. Don't you Don.

I appreciate Walter's comments, while you might not always agree with him he takes the time to research and review the facts. There are some here that are obviously not bothered by the facts and spout off with (God only knows where they get it) data and information in general that is just not true.

If you have got an opinion or a question this is the place for it. It is not the place to chastise someone just because they do not agree with you. Further, it grates me to see someone become, the only thing I call it is abusive, because of a difference of opinion. I wish those who choose to be that way would leave or be helped to leave before they run the rest of us off. However, I do not intend to leave because of one or two individuals. The vast majority of the folks here are just trying to get by. The experience level is all over the block, which is a good thing. It helps the people just starting out and gives the ones with some experience a chance to give something back.

However, giving it back does not include Card Blanche fire off both barrels when you do not agree with someone. I have to say (excluding the one or two mentioned above) I have not seen anyone ask a question or give an answer that was out of line, condescending, abusive, or whatever adjective you choose.

Kevin, I personally wish that you would deal with those people, throw them off the web site, not forever, just for the next 40 years or so. That way I will be out of the flying business one way or the other and will not have to endure more of the diatribe.

That's my story and I'm sticking to it.

just missed ya
 

Walter,

Well personally I agree with you. We should use our names, at the very least it should be in your profile. I tried to get my last in before you were here.

Intercoolers
 

Walter,

As far as intercoolers go I've talked to several people about them and all who have them agree that the engines run cooler. I guess I figured that if you reduce the heat over all that would help. That was the reason for that question.

Thanks

Mark.

Walter:

I don't have anywhere near the technical skills necessary to debate this from a scientific viewpoint. Rather, my reservations (which, by the way, are limited, because there are circumstances under which I endorse LOP) are mostly operational. These have been presented at length in this forum and are summarized in the third message of this thread:

http://www.337skymaster.org/messages...&threadid=1208

On the fourth message of that thread I refer you to a Lycoming document which goes into more detail on the operational concerns.

Ernie

Can we all try and stay on topic please.

Walter, in an e-mail you suggested a 20 degree C drop in temperature with your blast tube and cover. That is great and would make a real difference at altitude.

Is your test bed similar in configuration to our aircraft with the pump at the front (propeller end) of the engine, below the baffling?

When the RVP is only 7.3 in summer mix and it is a warm day at 18 K your margins for fuel vapourisation are very narrow.

I had thought the summer RVP was over 8, but perhaps you could comment on that and the effects for us please.

As a side note, apparently adding additional cooling to the dry vac. pumps increases their life significantly as well. That has been the comment of a certain Cessna 210 owner who writes in Flying at any rate.

Walter could you please give us the benifit of your experience with fuels and temperatures and the results of your measurements on the the fuel pump.

Regards - Dave

Mark:

Intercoolers and their effects are often misunderstood. They are VERY good things to have on a turbocharged engine because they widen the detonation margin. That is their major effect and it is a biggie. Based on the test data I have seen, *I* would not want to operate any turbocharged engine without an intercooler.

Intercoolers do not increase HP output as some suggest. There is no reason to reduce MP on intercooled installations as some claim. Why? Well, the increased exhaust backpressure that results from the use of an intercooler almost exactly offsets the increased HP from the cooler intake air. This effect is from a loss in volumetric efficiency. They forgot to calculate that factor in the equation! That statement usually starts a firestorm of protests from owners but we've proven this on the engine test stand as well. The numbers don't lie.

Ernie:

Two points:

1) the need for all cylinder monitoring is not related to whether or not one runs ROP or LOP. It is a very valubale tool in monitoring the health of the engine and it's value in leaning is actually quite minimal. If the engine will run smoothly LOP, it means that it has balanced F:A ratios and can be leaned using a single probe EGT guage with accuracy. If it will not run smooth LOP, then that means that it has poor F:A ratios ROP as well. I have seen so many engine saves by the use of a good engine monitor that I consider it a NoGo item for an IMC flight. The list of engine *saves* grows monthly.

2) the "Experts are Everywhere" document from Lycoming is interesting. It has one big problem in that it does not even agree with Lycoming's own engineering data. We pointed that out to Rick Moffet, the head of that divivsion of Lycoming who was responsible for its wriitng and he published it anyway. If you read it with care, here's what it really says. "LOP works. LOP operation does not hurt the engine. Pilots are too stupid to do it right."

No kidding, that's what it says. So Lycoming knows it works and says you are stupid.

Personally, I think you're not stupid. I teach engine management to a class of 35-50 pilots on a regular basis and find them to be a very savvy lot. Way above average and capable of very advanced techniques with a little training and education.

I read the post you directed me to (thank you) and found it to be of a vague nature where your worries are concerned. I find that to be a common situation. We can allay those generalized concerns if one asks a pointed question to which we can address a specific answer. A series of specific answers and the understanding that goes with them generally works to allay a generalized lack of understanding of the big picture. It's all in the education. I have found that *I* am a little leary and cautious of things I don't know a whole lot about.

So, what SPECIFIC question might anyone have?

Respectfully,

Walter