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I have been on the road for much of the last week, so I only made a bit of progress. I've got a few odds and ends to finish off, then I will attack the avionics installation.

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I was tempted to go with a 6 cylinder 220 hp PZL Franklin engine for my RV-8, but I eventually decided to go with the easier Lycoming installation. I also believed the Lycoming would be lighter. Well, David Brand went with the Franklin, and by paying careful attention to weight, aluminum gear legs, etc, he has a Franklin powered RV-8 that weighs 1110 lb without paint, which is probably less than my plane will weigh.

I just learned that there are photos of David Brand's engine installation posted in the Photos section of the Yahoo RV-8 Group. You'll need to be a member to see the photos. You can select to not get any of the group e-mail messages if you want. If you are already a group member, you should be able to go directly to the photos with this link.

You can also read his comments on the Franklin installation by going into the Messages section of the RV-8 list, doing a "Search Archive" for Franklin, and reading the messages from David Brand.

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This afternoon I got the top oil cooler hose trimmed to length and the second hose end assembled. The hose fits great, once I got it installed, although it is a bear to get the second end screwed on, as the hose isn't very long, so there isn't much flexibility.

I installed the first hose end on the remaining hose, then went to install the fitting in the engine. However I discovered that I didn't have the right mix of fitting angles left, so I hit a brick wall.

The first photo is a shot from above, showing the top oil cooler hose, which takes oil from the cooler and returns it to the engine.

Read on for more.

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I attacked the oil cooler hoses and fittings this afternoon. First I spent quite awhile studying the diagram in the back of the Lycoming Operators Manual to once again figure out which ports the oil cooler holes go to, and which one is Oil to Cooler, and which one is Oil from Cooler. I concluded that the IO-360-A diagram has the to and from ports reversed, as it shows them the reverse of all the other engine models, yet it refers to the same page to show other variations.

I assembled a hose end onto the length of steel braided hose, then temporarily threaded a 45° elbow into the Oil from Cooler port, and screwed the hose end on to it figure out what clock angle the elbow needed to be. Then I permanently installed the elbow. These things have a tapered thread to ensure a tight, leak free joint. This means the torque required to install the fitting keeps increasing as you screw it it. You want to tighten it very tight to be sure it doesn't leak, but if you turn it too far you can't back it off or it'll leak. It is a real guessing game to know whether you dare screw it in one more turn, or whether it will become so hard to turn that you can't get it to the angle you need. To further increase the level of difficulty, there is so much stuff hanging off the back of the engine that you don't have very good access to get a wrench on the fitting. Anyway, I scraped my knuckles, and a lot of bad words were said, but I managed to get the first fitting installed at a suitable angle. I've stopped to watch the NFL wildcard games, so I'll attack the next fitting tomorrow.

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I picked up a couple of messages on the RV-List (or see the message browser) about a forced landing by Tim Lewis. It seems that he was flying his RV-6A cross country and got into enough snow that it blocked the air filter, causing a forced landing. He did an excellent job getting the aircraft on the ground, and there were no injuries, nor was there any real damage to the aircraft.

This incident highlights the importance of an alternate air system, which is a design mod that I intend to make on my aircraft.

Read on for more details of Tim Lewis' incident.

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I was away from home over the Christmas period, and I couldn't work on the project, so I found some time to produce a spreadsheet to calculate the power output of the Lycoming IO-360. The Excel 4 spreadsheet basically replicates the graphical power chart found in the Lycoming Operator Manual for the IO-360-A, -C, -D, -J, -K and AIO-360 series. The zipped spreadsheet can be found at this link.

Note - I found several errors in the original version of this spreadsheet that cause it to fail at lower rpm conditions. There are also data errors for 2000 and 2100 rpm. I posted a corrected version a few minutes ago, at the same link. The corrected version can be identified by the version history info in the spreadsheet. The original version has no version history info in it.

I tried comparing the spreadsheet calculations to data from the POH for a 1977 Mooney 201 with a IO-360-A3B6 engine. However it quickly became clear that the data in the Mooney POH differs significantly from the Lycoming power chart. For example, at 8000 ft and 2700 rpm, Mooney claims that 23.6" manifold pressure gives 75% power, while the Lycoming power chart gives something like 21" for 75%. Either Mooney wanted to cruise at artificially high power to give good marketing numbers, or they measure manifold pressure differently than Lycoming or Lycoming has changed their power chart since 1977.

The accuracy of the spreadsheet calculations were validated by spot checks against the power chart from a Cessna 177RG POH (IO-360-A1B6D). The spreadsheet typically calculated one-half to one percent higher power for the same rpm and MP than was given in the POH. But, the spreadsheet is valid at maximum power mixture, and the POH data is for recommended lean mixture, so this is probably about correct.

The O-360 power spreadsheet that I created several years ago is still available at this link.

I have had several requests to do a 160 hp O-320 power spreadsheet. Someday when I am on the road and looking for something to do I will do one. When I am home I prefer to use my time building.