Postings are scarce on KR net this holiday period so I'm putting this in for anyone that's bored.
I admire you guys with your Subarus. A lot of engineering complexity goes into getting these engines to work well in an aircraft. Besides the thrust bearing issue Max Power is discussing, other Subaru issues are water cooling, turbocharging, reduction drives and through using these mechanical features, squeezing a huge amount of power out of such relatively small displacement engines - 2.2 litres - roughly the same as a GP 2180 or Revmaster 2100D. Instead of getting the rated 76 HP at 3400 RPM of a GP2180, the Suburus are pulling 182 HP from an engine of roughly the same displacement. I had a hangar neighbor, a retired aircraft engineer/designer, really put his heart and wallet into an EA-81 turbo installation on his Europa over a period of 10 years. He used the Marcotte PSRU (I've earlier incorrectly posted that he used the Eggenfeller). The Europa was designed for a Rotax but Wayne was attracted to the idea of using more power and making a really high flyer out of it with lots of range. He made many enhancements such as additional fuel capacity and added all the available factory options and, of course, put a dual GRT panel in it along with a plethora of back-up instruments. A really first class effort that taxed his excellent engineering skills. It took a lot of ingenuity to sculpt into the stock Europa design the radiators and plumbing necessary for the Suburu. The front end came out looking rather bulky and not very sleek looking but it was engineered well. When finished the engine ran well for quite a few hours on the ground and even ran well enough for Wayne to fly it up to the designated airport for flying off the 40 hours. Since it was a monowheel, he had a landing mishap in a crosswind so brought it back to Gillespie to install the tri-gear option that's offered for the Europa. After running the engine some additional time on the ground, when he again was headed to the 40 hour fly-off airport, the engine disintegrated shortly after takeoff. Wayne, although he had been doing very little flying while building this plane, landed it on a busy freeway without mishap and had a flatbed truck bring it back to his hangar. The engine had broken a timing gear and swallowed some valves and he hadn't the heart or trust in it to re-build it. He trashed it and all his elaborate plumbing, reshaped the cowling and put in a Rotax. He then sold it to a fellow who flies it (N951EU) out of Apple Valley. Wayne retired to the Ozarks. Pictures at this link show what it looked like with both the Suburu and the Rotax cowlings. https://tinyurl.com/rckpda3 Discussing things afterwords the concensus seemed to be that trying to squeeze so much power out of a 2.2 liter engine frequently causes failure due to heat and stress. Mainly stress. Same thing that kills people kills engines. Sometimes the reduction drive is also a factor. https://www.nbcsandiego.com/news/local/small-homemade-plane-lands-on-stat e-route-67/1928901/ What boggles the mind is how the automotive industry manages to make reliable engines by doing the same thing - developing huge horsepower numbers from very small displacement engines. I think they get away with it because the engines, while rated at a high HP, spend their lives loafing along at very low power settings - unlike engines used in aviation applications. The fastest production car in the world (until recently . . . it's always changing), the Koenigsegg Agera RS, gets its 1160 HP out of a 5 liter V8, about the same size engine as what's in my Olds 98. Mike KSEE ____________________________________________________________ Simple Trick Is Improving Men's Love Lives Med Journal http://thirdpartyoffers.juno.com/TGL3141/5e07aec070a72ebf4186st02vuc _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
