Eggenfellner - Page 2

frankh · #11 10-07-2006, 08:54 PM

Good point on the max CR of 8.5:1.And also it will only be Fuel injected motors that can run LOP.

AS to the don't run LOP thing thats interesting. I agree there is a bit of an art to it but with my Dynon at least it makes finding peak a snap...as long as you give the readings time to settle.

In fact readin the Deakin articles it would appear to be safer to be on the lean side of peak rather than the rich.

I wonder if it would be better to find peak from the lean side rather than the rich...assuming your motor keeps running well on the lean side then you can enrichen the mixture to find the peak values and then you could maybe feel more comfortable doing it really slowly so you get the actual peaks.

This is in theory in my case because my motor gets rough due to the fact I have not balanced the flows yet.

Anyway...yes please do dig up the article and maybe we can thrash it out here on the forums.

Cheers

Frank

cjensen · #12 10-07-2006, 09:06 PM

I will certainly do my best to find it. It was actually a little booklet put out by Lycoming last fall, if I remember correctly.

Frank, I really appreciate the civility of this conversation to this point (even being a short one so far). Too many times, the bashing gets threads out of hand.

David-aviator · #13 10-07-2006, 09:46 PM

There are lots of pros and cons re Subaru and Lycoming.

A distinct pro for Subaru is fuel. I've used 87-91-93 mogas and 100LL, the engine does not seem to care. At one point I checked take off timing comparing 100LL and 87 mogas, the ECU does retard ignition slightly with the lower octane mogas. Fuels have been mixed and it matters not.
I add a lead inhibitor when using 100LL as lead is no good for any modern engine.

It is a very good ideal to check vapor pressure when using mogas, especially when going from winter to summer blend fuel in the spring. I have found a load of 93 at less than 34 kPa's (meter red line) and drained it for my auto. The replacement 87 tested at 45 kPa's, a clear indication of winter vrs. summer fuel. Winter blend matters not in cold weather, but it can be a problem in spring with an early heat wave. The Hodges meter says 34 kPa is the red line and even at that it is good up to about 10,000'. If you worry about vapor pressure or do not want to test for it, use 100LL. It always tests around 62 kPa's which is good up to about 22,000', higher if the fuel cools in climb..

Back to the original question on weight, I weighed my H6 before install and it was 394 lbs. including the mount. With the MT prop the package came in at about 425. Empty weight of the airplane on certified scales was 1175. The CG was in range but a bit more forward than I like, so 9 lbs of ballast has been installed at the HS. It will now trim up hands off on final. This CG situation is also true of IO360's with CS prop. I did not weigh the 2.5 Subaru, but it seems to me it is about 40 lbs lighter than the H6.

dd

cjensen · #14 10-10-2006, 10:30 AM

Frank,
I found the Lycoming letter about this issue. It's Lycoming SSP700, and talks about leaning procedures, and the "experts" with new leaning products and techniques. It dates from 2000, not last fall as I thought...I first read it last fall. They do not say *NOT* to operate LOP, just be cautious if you do. Here's a small excerpt from the literature-

Quote:

"Lycoming recommends cruise operation at peak EGT or TIT, which is the point where the best economy range starts. For optimum service life, Lycoming suggests operating 50 degrees rich of peak EGT or TIT."

I'll start a new thread with the whole article, so everyone can read the whole thing, and make their own remarks on it.

jcoloccia · #15 10-10-2006, 11:03 AM

Quote:

Originally Posted by cjensen

Frank,
I found the Lycoming letter about this issue. It's Lycoming SSP700, and talks about leaning procedures, and the "experts" with new leaning products and techniques. It dates from 2000, not last fall as I thought...I first read it last fall. They do not say *NOT* to operate LOP, just be cautious if you do. Here's a small excerpt from the literature-

I'll start a new thread with the whole article, so everyone can read the whole thing, and make their own remarks on it.

Funny you should mention that. I just went on a cross country on Saturday and decided to see if I could hit the numbers in the Piper Warrior POH. The charts said something like "Best Economy when leaned per Lycoming instructions for Best Economy".

So I looked it up...

At 9000ft and WOT, pulling the mixture until I encountered engine roughness (not RPM drop...came well after RPM drop) is clearly LOP on the EGT...at least in the warrior, carb and all. I've been pretty quiet on the LOP thing but I never really understood what all the fuss is about. Doesn't seem like anything new or exciting since practically every POH I've ever read recommends leaning until engine roughness to get best economy, and this always occurs (for me, anyhow) somewhere LOP. And yes, I hit the numbers right on the money. I was within 3/10 of a gallon and airspeed was actually a touch better than the POH.

So there

Looking forward to that article, Chad. I'd love to see what Lycoming has to say about it!

frankh · #16 10-10-2006, 12:07 PM

says to run at like 50F ROP...If I remember from the Deakin articles thats like the worse place you can run the motor..

The LOP thing was the difference between making it home and going for a swim on many of the early radial transports and bombers. I think if done correctly (and it may well be that Lycoming has seen many warranty claims from careless pilots...Finding peak is at best a fiddly pastime with lots of head in the cockpit time) and prefer not to go there, void the warranty and all that.

Frank

frankh · #17 10-10-2006, 12:16 PM

Quote:

Originally Posted by David-aviator

There are lots of pros and cons re Subaru and Lycoming.

A distinct pro for Subaru is fuel. I've used 87-91-93 mogas and 100LL, the engine does not seem to care.

dd

I think the evidence is showing that Lycomings don't care either....The more I research this the more I realise that Peterson had to do a LOT of work to be able to issue STC's for certified airplanes, including testing detonation margins on pretty substanderd fuel.....I need to get to the bottom of the "ethanol forbidden" thing (I just don't have enough data to prove to myself why its such a bad thing PROVIDING you have a well designed fuel fystem like what I got)...It maybe bad, I just don't know yet.

Anyway, just to say the only reason that soobs have a fuel advantage is basically the intertia (fear, beaurachracy)around running Lycs on Mogas*...The only advantage the soob then has is being able to run regular gas vs premium...Not a big deal in the grand scheme of things, except maybe you can find supplies of regular at your local FBO pump maybe.

*Standard disclaimers...Max CR 8.5:1, normally aspirated, STC (or RV) in hand, sensible timing etc.

Frank

cjensen · #18 10-10-2006, 12:27 PM

Quote:

Originally Posted by jcoloccia

[snip]Looking forward to that article, Chad. I'd love to see what Lycoming has to say about it!

I gave it to our computer guy to scan in and create a .pfd. As soon as I have it, I'll post it!

David-aviator · #19 10-10-2006, 06:00 PM

Quote:

Originally Posted by frankh

l.....I need to get to the bottom of the "ethanol forbidden" thing (I just don't have enough data to prove to myself why its such a bad thing PROVIDING you have a well designed fuel fystem like what I got)...It maybe bad, I just don't know yet.....

Frank

ALL the mogas I've been using has up to 10% ethanol. If it is an issure of fuel system materials compatiblitly with Lycoming, that sure could be fixed.

So far as vapo pressure is concerned, I believe if a fuel tests at say 48 kPa's, with or without ethanol, that's what it is.

dd

frankh · #20 10-10-2006, 08:34 PM

That Superior found unacceptable levels of boiling in the injector lines using the standard 28thou injector restictors (at least that is what Airflow Performance standard ones are). They referred to ethanol causing VL...well of course injector line boiling is NOT VL, and true vapour lock can be fixed by putting the pump in the right place hydraulically speaking.

So I dunno, The AFP system is ethanol compatible so thats not an issue either.

But I will find out one way or another.....

Anyone reading this running ethanol laced mogas in a Lyc???

Frank