Should I be concerned over these testdata for my new Lyc XIO-360?

ao.frog · #1 11-02-2013, 02:38 AM

I need some advice from you engine experts out there: in 2010 I bought a new Lyc XIO-360 from Vans for my -7.
It was run twice at the Lyc factory, then shipped to me.
As part of the paperwork with the engine, there where reports from the two test-runs.

Yesterday I was going over the paperwork in preparation for the very first engine start, and I noticed that both runs had three items which was either described or marked with "rewiew".

I'm wondering of these three items are something I schold be concerned about? Does it need fixing before first flight for example? Or is it normal variations one schould expect from a new engine?

Look in the "variations" column from test-run # 1: (upper right corner)
There's three items listed

Here's the report from test-run #2:

The same three items are marked as "rewiew" in the report.

Is this something to get fixed or be worried about?

I have little detailed knowledge of aircraft engines, so I'm hoping someone out there can tell me what these three remarks actually means?

(Mel or Malon, are you guys out there?

)

RV10inOz · #2 11-02-2013, 05:49 AM

I assume this is all about injector nozzle flow rates.

See what your Gami spread is.....if it were me just install a set of Gamijectors.

You can see Lycoming are not bothered at all to get your F/A ratio and flows correct.

AirbusPilot · #3 11-02-2013, 06:38 AM

They just were calibrating fuel system, I think the problem will be they leave it like that, but they review/fixed so just go ahead and fly your plane

Robert Anglin · #4 11-02-2013, 06:09 PM

This is within limits but not uniform. 'Very few are." You will have lots of time after you get your bird up and flying to look in to fine tuning these flows. Unless you get some very bad "E.G.T." reading, I would wait till it gets 50-100 hrs. on it before you start fine tuning it. Every new one takes some time to settle down and find its own attitude. If you find that you don't like it after it settles in for the long hall, yes Gamis are a good thing to look into.
Hope this helps. Yours as always R.E.A. III # 80888

SteinAir · #5 11-02-2013, 07:15 PM

Gami's are good, but Don at Airflow Performance will treat you even better - give him a shout with your info and he'll be able to get you perfectly dialed in.

Cheers,
Stein

pierre smith · #6 11-03-2013, 04:47 AM

+1 for Don at AFP. His injector orifices go down to half thousandths. We had .025's to start with and needed .0251/2 for the two center cylinders...amazing results.

Best,

DanH · #7 11-03-2013, 07:08 AM

Anybody here familiar with these charts and the dyno setup? Regarding the review items in question...

What does "Airflow@AF-1000" actually mean? I assume air in pounds per hour.

Fuel Flow Limits and Fuel Nozzle Limits appear to be quantity and pressure. At 82.68 PPH the measuring point would have to be prior to the fuel divider, as it's a little less than 14 GPH. No idea which nozzle they refer to here. The 10.9 Hg is perhaps differential pressure as compared to manifold pressure? Anybody know? Last, at what RPM is this test done? Loaded to 2700 while throttled to 1000 PPH air?

Observation...

The Rated Power figures further down the page are interesting...2712 RPM, 27.17 MP, and a "Flow Limits (PPH)" of 1041. That's too large to be a fuel flow, so it must be airflow. The theoretical air capacity of a 4-stroke is (RPM x Displacement)/3456 = CFM, so (2712 x 361)/3456 = 283 CFM. Air at the given barometer (29.2) should be about 0.075 lbs per cubic foot, so that's 21.225 lbs per minute, or 1273.5 PPH. 1041/1274 = 82% volumetric efficiency, which puts it in the "truck engine" performance category. Always nice to have real numbers.

RV10inOz · #8 11-03-2013, 05:18 PM

I wonder too......

I also wonder how a recent Lycoming IO360 could have made it out the door with the FCU for an IO320. It certainly flows the wrong fuel flow

Don at Airflow · #9 11-04-2013, 09:00 AM

What Lycoming does when they dyno an engine is to (correctly) set a given mass airflow through the engine then read the hp output. This method was established in conjunction with the Bendix Corporation beck in the 50?s. I actually spent many days in the engineering air box, calibrating their airflow measuring equipment, then made from PS-7 throttle bodies. Today I?m sure all their test cells use electronic airflow measuring equipment. Additionally they measure the fuel flow in PPH. This of course can be directly related to BSFC a measurement of the engine?s health and efficiency. The limits for fuel flow for this engine at 1000 PPH air flow show 83.1 to 92.1 PPH or a .083-.092 fuel air ratio). The engine was at 82.68 PPH, so it?s 0.5% out of the lean limit. Personally I wouldn?t worry about it. The other limits for review are nozzle backpressure measurements. These are pretty much meaningless to the operation of the engine, and are strictly a result of the nozzle size. Back in the day there wasn?t electronic fuel flow measuring devices, so since we knew the nozzle size, you could establish a relationship between nozzle back pressure and fuel flow. These were given to Lycoming and they established fuel flow limits for the engines off of these charts. They still use them today even though they have digital or on the older dyno stands they had Cox flow meters. I guess you could use this as a trouble-shooting device if you had a clogged nozzle. The reality of it is if you are running Bendix (Precision) or Airflow Performance fuel injection, it doesn?t matter what the nozzle back pressure is because the fuel control establishes the fuel air ratio that is delivered to the engine. If the nozzles were bigger or smaller (which would change the nozzle back pressure reading for a given fuel flow) the fuel flow delivered to the engine would still be the same.

On another note if you had a fuel control for a 320 and installed it on a 360 the engine would still run fine. The fuel air ratio for the setting for the IO-320 is around .085. The fuel air ratio setting for the 360 is around .085. So basically either unit would run either engine. There is a parts list RSA-5AD1 that is used on an IO-360 and IO-540 with no change in the parts list or calibration.

Don

ao.frog · #10 11-04-2013, 11:41 AM

.... for the replies guys! Now I feel alot better!
A special thank you to Don at Airflow for taking the time to write the long comment. I'm learning something new every day in this RV-building business!

Now I'll get this bird in the air and see how things work. It'll be interesting to observe CTH's ang EGT's as well as the other numbers.

Hopefully first engine start is in a couple of weeks and first flight just after New Year.

Regards Alf Olav