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Search: Posts Made By: Walter Atkinson
Showing results 1 to 35 of 168
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Forum: The Pacific: General Aviation & Questions
2nd Oct 2016, 13:26
Replies: 28
Views: 5,135
Posted By Walter Atkinson

This is a copy of an article I wrote for an...

This is a copy of an article I wrote for an aviation magazine a while back:

Carburetor icing is one of those pesky problems that can ruin your day and remains a serious problem for light aircraft...
Forum: The Pacific: General Aviation & Questions
26th Jun 2016, 13:50
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Mixture affects thetaPP and ICPs, which affect...

Mixture affects thetaPP and ICPs, which affect the thermal boundary layer, which affects the rate of heat transfer from the combustion gasses into the wall of the combustion chamber.

This is...
Forum: The Pacific: General Aviation & Questions
11th Jun 2016, 15:58
Replies: 47
Views: 16,766
Posted By Walter Atkinson

I'm pretty sure they went with option "B", then...

I'm pretty sure they went with option "B", then refined with option "A" if things turned out differently than expected. Many times, the testing to find out if "A" was what they wanted was not...
Forum: The Pacific: General Aviation & Questions
9th Jun 2016, 14:29
Replies: 47
Views: 16,766
Posted By Walter Atkinson

The J2BD does make rated power with the timing...

The J2BD does make rated power with the timing the way it is. Actually, the retarded effective timing helps it produce more power at TO power. Most engines can make more power with slightly...
Forum: The Pacific: General Aviation & Questions
9th Jun 2016, 03:45
Replies: 47
Views: 16,766
Posted By Walter Atkinson

Sorry for the brain fart. The timing is set at...

Sorry for the brain fart. The timing is set at 20dBTDC and actually occurs at about 16dBTDC, obviously not at 16dATDC! I guess I got my As and Bs mixed up!!!

This probably happens as a result of...
Forum: The Pacific: General Aviation & Questions
7th Jun 2016, 22:37
Replies: 47
Views: 16,766
Posted By Walter Atkinson

Concerning the dual-drive mags: They are...

Concerning the dual-drive mags:
They are properly timed at 20dBTDC. BUT, the sparks actually occur at approximately 16dATDC. This is quite probably not known by Lycoming. (Actually, I'm very,...
Forum: The Pacific: General Aviation & Questions
4th May 2016, 19:11
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Thanks for posting those links. I'll comment as...

Thanks for posting those links. I'll comment as I get a chance to review them.

http://ntrs.nasa.gov/archive/nasa/ca...9930081891.pdf

I have taken a cursory look at the issues on the ink above...
Forum: The Pacific: General Aviation & Questions
16th Apr 2016, 13:36
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** That is interesting, I wonder if it was be...

***
That is interesting, I wonder if it was be design or by luck... I would suggest for at least one Lycoming engineer is was luck
***
I have a very high level of confidence that it was not luck,...
Forum: The Pacific: General Aviation & Questions
15th Apr 2016, 14:11
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** The example that I had in mind was...

***
The example that I had in mind was advancing the throttles to full, with the mixture still set at a sensible LOP setting
***

Lycoming got it right on their full controller. When one...
Forum: The Pacific: General Aviation & Questions
14th Apr 2016, 22:47
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Here's a thought about the dangers of screwing up...

Here's a thought about the dangers of screwing up the mixture.

1) There is nothing one can do when LOP that hurts the engine. Period.
2) There are any number of things one can do to harm the...
Forum: The Pacific: General Aviation & Questions
12th Apr 2016, 19:46
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** I would believe that, if I had the skills...

***
I would believe that, if I had the skills and was asked to design an engine I would design it LOP as well, doesn't mean when it got built there might be some limitations not intended that are...
Forum: The Pacific: General Aviation & Questions
12th Apr 2016, 15:56
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** Would be nice to see that data, but it...

***
Would be nice to see that data, but it appears entirely plausible given that it appears this engine was designed for LOP at cruise power.
***
It was operated ROP for a number of years. Poor...
Forum: The Pacific: General Aviation & Questions
12th Apr 2016, 13:23
Replies: 383
Views: 68,076
Posted By Walter Atkinson

oogers: The 600 to 3600 hour TBO information...

oogers:
The 600 to 3600 hour TBO information came from "Basic Theory", a publication by Wright Aeronautical (known as the WAD manual). It was published in (IIRC) 1957, and was based on 400 million...
Forum: The Pacific: General Aviation & Questions
10th Apr 2016, 13:38
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** I agree about optimizing the PP. On valve...

***
I agree about optimizing the PP. On valve life, the flight engineer instructor says it favoured longer life, you say it doesn't. I have no way of confirming either way. It might annoy you that I...
Forum: The Pacific: General Aviation & Questions
10th Apr 2016, 13:19
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** Your engine is not an air compressor. ...

***
Your engine is not an air compressor.

In an air compressor, the piston is adding energy to the gas (compressing it) which heats the gas. In an engine, the piston is extracting energy from the...
Forum: The Pacific: General Aviation & Questions
9th Apr 2016, 15:40
Replies: 383
Views: 68,076
Posted By Walter Atkinson

The cruise limit on CHT was not that high. It...

The cruise limit on CHT was not that high. It was that high where it was measured--on the back side of the hottest cylinder, under the spark plug as a ring gasket. It was known that the CHT was...
Forum: The Pacific: General Aviation & Questions
9th Apr 2016, 14:10
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** Surely Lindy's method would have been...

***
Surely Lindy's method would have been useful en route to combat zones or when engaged in distant reconnaissance trips?
***

One would think so, but as Kirby pointed out, "The whole damned...
Forum: The Pacific: General Aviation & Questions
9th Apr 2016, 14:01
Replies: 383
Views: 68,076
Posted By Walter Atkinson

It was war-time. The Top Secret nature of the...

It was war-time. The Top Secret nature of the project was important to keep from the enemy. Afterward, It was reduced to confidential.

It matters not. The issue is that it has been widely...
Forum: The Pacific: General Aviation & Questions
8th Apr 2016, 17:58
Replies: 383
Views: 68,076
Posted By Walter Atkinson

While Lindy did use a LOP setting to fly the Ryan...

While Lindy did use a LOP setting to fly the Ryan across the Atlantic in 1927, the Lindberg myth about LOP in the P-38 persists even though it is contradicted by those who were there. According to...
Forum: The Pacific: General Aviation & Questions
7th Apr 2016, 23:38
Replies: 383
Views: 68,076
Posted By Walter Atkinson

During a preignition event, the valve temperature...

During a preignition event, the valve temperature is rising at the alarming rate of as much as 2 degrees per second. While this is happening, the EGT is going down significantly.

During...
Forum: The Pacific: General Aviation & Questions
7th Apr 2016, 23:02
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Remember the purpose of the NACA report. Some US...

Remember the purpose of the NACA report. Some US engineer during WWII decided that we needed to run the B-24 Liberator LOP to get the range AND increase the bomb load. Some General said, "That's...
Forum: The Pacific: General Aviation & Questions
7th Apr 2016, 15:02
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Well, well, well. If one says a stupid thing...

Well, well, well. If one says a stupid thing fifty million times, it is still a stupid thing. paraphrased from Anatole France.

If one looks at the CHT and ICP curves and valve temp, one would...
Forum: The Pacific: General Aviation & Questions
5th Apr 2016, 21:38
Replies: 383
Views: 68,076
Posted By Walter Atkinson

*** All I was saying was if we could still get...

***
All I was saying was if we could still get 100/130 fuel the majority may still prefer the extra power of 130 octane but the only way to get it would be ROP.
***
130 octane does not result in...
Forum: The Pacific: General Aviation & Questions
4th Apr 2016, 02:00
Replies: 383
Views: 68,076
Posted By Walter Atkinson

LOP theory????? That is truly funny. ...

LOP theory?????

That is truly funny.

It's factual. One might enjoy reading Taylor's two-volume engineering texts--or Haywood's texts.

I've read both.

It's true. There really is a time...
Forum: The Pacific: General Aviation & Questions
4th Apr 2016, 01:54
Replies: 383
Views: 68,076
Posted By Walter Atkinson

According to the 1943 NACA report referenced,...

According to the 1943 NACA report referenced, those who think that valve temp is in any way related to EGT must reconcile the fact that as EGT is going UP from 25dF ROP to peak EGT the valve...
Forum: The Pacific: General Aviation & Questions
16th Mar 2016, 20:07
Replies: 33
Views: 6,548
Posted By Walter Atkinson

Andy: 1000dC = 1832dF if my calculations are...

Andy:

1000dC = 1832dF if my calculations are correct. That's still about half of the combustion temp.

FWIW, and who cares?? <g>
Forum: The Pacific: General Aviation & Questions
15th Mar 2016, 01:14
Replies: 33
Views: 6,548
Posted By Walter Atkinson

The gases are not 1000 degrees. They are...

The gases are not 1000 degrees.

They are 3500-3800dF and being pushed by about 800-1000 psi of combustion pressure. (on average)

Now think about it. :ok:
Forum: The Pacific: General Aviation & Questions
11th Mar 2016, 21:33
Replies: 33
Views: 6,548
Posted By Walter Atkinson

Ultralights: *** my meaning being that the...

Ultralights:

***
my meaning being that the exhaust gas temps leaking through into the void, would be no different to the gas temperatures in the combustion chamber if the engine was 100% fine and...
Forum: The Pacific: General Aviation & Questions
10th Mar 2016, 21:15
Replies: 33
Views: 6,548
Posted By Walter Atkinson

The temperature of combustion being in the...

The temperature of combustion being in the 3500-3800dF range makes that a serious blow torch. This is noting like EGT level heat.

I would NOT have expected to hear it. We can't even hear severe...
Forum: The Pacific: General Aviation & Questions
10th Mar 2016, 20:48
Replies: 383
Views: 68,076
Posted By Walter Atkinson

I have only excused myself from providing the...

I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth. If you could explain to me how to post 16 hours of data presentation in a post on the...
Forum: The Pacific: General Aviation & Questions
8th Mar 2016, 20:37
Replies: 383
Views: 68,076
Posted By Walter Atkinson

All of this talk about hotter EGTs/TITs during...

All of this talk about hotter EGTs/TITs during LOP ops is interesting. Where I went to school, 50dF ROP and 50dF LOP were the same temperature! The OEMs recommended 50dF ROP! But then, I did go to...
Forum: The Pacific: General Aviation & Questions
8th Mar 2016, 03:41
Replies: 383
Views: 68,076
Posted By Walter Atkinson

In certain circumstances, it can, but it won't be...

In certain circumstances, it can, but it won't be by much. Increasing MP results in higher combustion temps and a slightly faster flame front speed. The faster flame front results in an earlier...
Forum: The Pacific: General Aviation & Questions
8th Mar 2016, 03:37
Replies: 383
Views: 68,076
Posted By Walter Atkinson

That's pretty normal for NA engines. Why won't...

That's pretty normal for NA engines. Why won't they run leaner? The fuel atomization and vaporization is not as good as in turbos that will run as far as 120dF LOP quite smoothly.


The question...
Forum: The Pacific: General Aviation & Questions
7th Mar 2016, 22:17
Replies: 383
Views: 68,076
Posted By Walter Atkinson

Guess so! Sorry, if that was the case.....

Guess so! Sorry, if that was the case.....
Forum: The Pacific: General Aviation & Questions
7th Mar 2016, 15:05
Replies: 383
Views: 68,076
Posted By Walter Atkinson

OK, I'm ready to learn. What were his...

OK, I'm ready to learn. What were his recommendations and does he have hard data to back it up? I'm serious. I'm ready to learn.

Or, is he just another person with an unsupported opinion.

As...
Showing results 1 to 35 of 168
 
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