carusoam Posted January 11, 2022 Report Posted January 11, 2022 All really good points… There are three temps that always get discussed… CHT limits and TIT limits… and oil temps too… 1) the manufacturers like to show that flying in flaming dragon mode is a possibility…. 2) Some owners have the budget and desire to fly in flaming dragon mode often…. 3) Some owners prefer stuff to last as long as practical… 4) The challenges with high temps… erosion increases, and oil life decreases…. 5) Always be on the lookout for the health of the exhaust system between the exhaust valve and the turbo… it probably glows red for a lot of the flight… the tube walls thin as the hours increase… 6) Turbo vanes… their tensile strength decreases with temperature… and turning tens of thousands of rpms puts a lot of stretching force on them…. And as they get super hot… they grow in length like anything else… their failure mode is contacting the turbo case and wearing the vanes down…. As the vanes become nubs their efficiency starts to wane… and the MP can’t keep up… 7) So… the MSers around here doing research to keep things running the longest… find CHTs kept under 380°F when able is a good guideline… and TIT’s under 1650°F is also a good guideline… And the turbo cooling occurs just before landing… no need for for a cooling period as ground ops aren’t any good for cooling… 8) Exhaust valve cooling and turbo cooling use a lot of oil flowing buy to remove heat…. Oil degradation begins as low as 240°F…. This is a very time sensitive occurrence…. We get away with cooling things that are reaching typical EGTs… because the oil doesn’t stay there very long… and we use many quarts of oil in the oil pan… 9) real problems begin when the oil flow in the cooling channels get blocked or restricted… valve guides can get filled with carbon deposits… slowing the oil flow and increasing its temperature… 10) There are a few threads around here regarding reaming out valve guides, and making sure the scavenger pump is working properly… 11) Oil life, oil cooler, and OilT control are a whole other topic… Summary, heat and time are the enemy of metals and oils… PP thoughts only, not a mechanic… Best regards, -a- Quote
Hank Posted January 11, 2022 Report Posted January 11, 2022 14 hours ago, carusoam said: alve cooling and turbo cooling use a lot of oil flowing buy to remove heat…. Oil degradation begins as low as 240°F…. This is a very time sensitive occurrence…. We get away with cooling things that are reaching typical EGTs… because the oil doesn’t stay there very long… and we use many quarts of oil in the oil pan… We really don't! In my little O-360 [5.9 liters], I keep 6 quarts and refill somewhere above 5 quarts [~1 quart per liter]. I have a car in my garage with a 5.3 liter engine, fuel injected but also normally aspirated, that requires 11.5 quarts to fill up, and the "Add Oil" line on the dipstick is 2½ quarts down [2 quarts per liter]. That's a lotta oil in the pan! For comparison, the TIO-540 is 8.8 liters . . . . . One quart per liter would be 8-9 quarts; two per liter would be 17 quarts. I can believe 8 quarts for the Bravo engine, but not double that figure. And at an average speed of 180 KTAS, in 25 hours the Bravo covers 5175 statute miles, so an oil change is due just like on cars built in the same timeframe. I still do my cars that often. Oil is cheaper than engines, even comparatively inexpensive automobile engines. 1 Quote
carusoam Posted January 11, 2022 Report Posted January 11, 2022 5 hours ago, Hank said: We really don't! In my little O-360 [5.9 liters], I keep 6 quarts and refill somewhere above 5 quarts [~1 quart per liter]. I have a car in my garage with a 5.3 liter engine, fuel injected but also normally aspirated, that requires 11.5 quarts to fill up, and the "Add Oil" line on the dipstick is 2½ quarts down [2 quarts per liter]. That's a lotta oil in the pan! For comparison, the TIO-540 is 8.8 liters . . . . . One quart per liter would be 8-9 quarts; two per liter would be 17 quarts. I can believe 8 quarts for the Bravo engine, but not double that figure. And at an average speed of 180 KTAS, in 25 hours the Bravo covers 5175 statute miles, so an oil change is due just like on cars built in the same timeframe. I still do my cars that often. Oil is cheaper than engines, even comparatively inexpensive automobile engines. I probably used the wrong frame of reference… I compared my 300hp car to the 300hp aviation engine that holds about 2X the oil… certainly, the amount of work done… the plane uses up the same amount of oil in a shorter amount of time…. Oil cooled engines typically keep a fair amount of oil in inventory…. Sort of an OWT… since the oil cooler does most of the cooling… Thanks for sharing the details Hank! Best regards, -a- Quote
Bravoman Posted January 12, 2022 Report Posted January 12, 2022 On 1/11/2022 at 1:36 PM, Hank said: We really don't! In my little O-360 [5.9 liters], I keep 6 quarts and refill somewhere above 5 quarts [~1 quart per liter]. I have a car in my garage with a 5.3 liter engine, fuel injected but also normally aspirated, that requires 11.5 quarts to fill up, and the "Add Oil" line on the dipstick is 2½ quarts down [2 quarts per liter]. That's a lotta oil in the pan! For comparison, the TIO-540 is 8.8 liters . . . . . One quart per liter would be 8-9 quarts; two per liter would be 17 quarts. I can believe 8 quarts for the Bravo engine, but not double that figure. And at an average speed of 180 KTAS, in 25 hours the Bravo covers 5175 statute miles, so an oil change is due just like on cars built in the same timeframe. I still do my cars that often. Oil is cheaper than engines, even comparatively inexpensive automobile engines. The hours to miles comparison/analysis is interesting. As to automobiles, I have heard from reliable sources over the years that manufacturer recommendations to change oil at 7500 or 10,000 miles is driven more by environmental concerns, i.e. the EPA than what is truly good for the motor. Quote
Tx_Aggie Posted May 14 Author Report Posted May 14 Resurrecting my old thread having “move up” thoughts again. I’ve seen a few posts from bravo owners on trouble sourcing v-band clamps and even being grounded until one is found. will this be an ongoing issue or has the factory helped resolve it? Quote
LANCECASPER Posted May 14 Report Posted May 14 5 hours ago, Tx_Aggie said: Resurrecting my old thread having “move up” thoughts again. I’ve seen a few posts from bravo owners on trouble sourcing v-band clamps and even being grounded until one is found. will this be an ongoing issue or has the factory helped resolve it? This is a Lycoming Turbo engine issue, and to a lesser degree a Continental Turbo engine issue, since their supply seems to have come back, not just a Mooney issue. The v-clamp decision by the FAA may have been a good one for safety, but what it did was immediately deplete all supply and companies that make them have to work production in to their schedules. At the price they are getting for the clamps there is enough incentive to make and sell them, so the supply will balance once the backorders are filled. 1 Quote
Dammit Bill Posted May 16 Report Posted May 16 If I may…I was out of GA for many years but got back in about five years ago. I went from a 150 hp 172, two a 230 hp 182, to a Bravo. Here’s my take. I wanted an airplane that could get up above weather. 310 hp ovation is only going to produce about 155 hp at 12,000 feet. I typically climb effortlessly to 17,500’ in my bravo. It’s certified known icing, has plenty of redundancy, and I can run lean of peak. I get 176 kts and 14.5 gallons per hour. For me, I like the ability to climb as high as 250 to get above and around weather. Yes, having a turbo may present more of a financial obligation. Should there be an issue. I could run my engine much harder and get 200 kn or more but I see no need.I find the Bravo to be exactly what I want, and need. Sent from my iPhone using Tapatalk Quote
LANCECASPER Posted May 16 Report Posted May 16 15 hours ago, Bill C said: If I may… I was out of GA for many years but got back in about five years ago. I went from a 150 hp 172, two a 230 hp 182, to a Bravo. Here’s my take. I wanted an airplane that could get up above weather. 310 hp ovation is only going to produce about 155 hp at 12,000 feet. I typically climb effortlessly to 17,500’ in my bravo. It’s certified known icing, has plenty of redundancy, and I can run lean of peak. I get 176 kts and 14.5 gallons per hour. For me, I like the ability to climb as high as 250 to get above and around weather. Yes, having a turbo may present more of a financial obligation. Should there be an issue. I could run my engine much harder and get 200 kn or more but I see no need. I find the Bravo to be exactly what I want, and need. If you're going to fly up to FL250 or even the 17500 that you mention it's good to have a pulse oximeter that you use to check often how you are doing. Also good to have a backup portable to your oxygen. 1 Quote
Jerry 5TJ Posted May 16 Report Posted May 16 2 hours ago, LANCECASPER said: If you're goinf to fly up to FL250 ad even the 17500 that you mention it's good to have a pulse oximeter that you use to check often how you are doing. Also good to have a backup portable to your oxygen. …above FL180 if you have a second pilot or even a right seat helper it is good to have them breathing on a different oxygen system than yours. 1 Quote
Fly Boomer Posted May 16 Report Posted May 16 2 hours ago, Jerry 5TJ said: …above FL180 if you have a second pilot or even a right seat helper it is good to have them breathing on a different oxygen system than yours. I have a backup (portable) system, but had not thought about putting the right-seater on the second system. Thanks! Quote
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