DVA

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About DVA

  • Rank
    Senior Member

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  • Website URL
    www.vanallenairmotive.com

Profile Information

  • Gender
    Male
  • Location
    Allentown PA
  • Reg #
    N9153Z
  • Model
    M20M

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  1. Fuel Contamination

    I think if there was a fuel anomaly at such a large airfield that it would become known pretty quickly - not implying it can’t happen. Maybe a call to the flight school to see if they had any issues during that time frame? Did you have any recent work on sealing or patching of your tanks? And did you find this on both sides?
  2. Oxygen refills is Pa/Nj area

    Norm, Stop over and say hello at KXLL in Allentown, we’d love to meet ya, we’ll show you the shop and fill you up for $20. Best regards, Dave [edit - that’s an exclusive super secret Mooneyspace fanboy only deal, so no 737’s! lol ]
  3. The sealants used to create the fuel cells, according to PPG and Flamemaster, two manufactures’ of the products, say no. The products do not rely on any outside liquid to remain in-tact. However, the natural flexing of the fuel cells do contribute to breaches, and we see that on inspection when we do repairs. Keeping fuel, at some level above empty appears as if its a good thing to help prevent quickly changing the aggregate temperature in and around those cells. The fuel acts to provide some hysteresis in the speed of heating and cooling and empirically at least, helps to keep temperature induced flexing down. But that could all be BS, it just seems to be logical. Always keep enough fuel in the plane to be able to have fun when you want to. :-) DVA
  4. M20M LOP Discussion

    re: TIT IMHO there are three factors to consider here; 1) we should all agree TIT matters, and we should all agree that EGT absolute temps don’t “really” matter. 2) We should agree that there is much more incorrect (folklore) vs factual information out there as to why TIT matters and why EGT doesn’t “really”, and 3) we should agree that a Mooney airplane / engine combination is generally no different from that of any other like-type airplane / engine combination. No one will successfully argue against the fact that the hotter you make steel and aluminum the more they will fatigue and eventually fail. So given that, my comments below are driven by a cooler is better premise, however, I am not afraid of recommended heat ratings or running my engine at those temperatures. I recently had a long discussion at KOSH with a design engineer at Hartzell and we talked extensively about turbochargers from the manufacturers' perspective. I’ll abbreviate the convo here but I would love to discuss any of this in more detail. I asked specifically about the M20M’s dual max POH TIT (1750 max lower altitudes to 1650 max at higher altitude) I just couldn’t wrap my head around why the diff in max temps? The turbo has no idea it’s higher up in the air and temp is temp as fast as the materials are concerned - so why the diff and why don’t we see that on most “other” turbocharged piston airplanes? His answer surprised me and immediately made complete sense. Paraphrasing: Hartzell rates that particular turbocharger for a max *continuous* TIT of 1750dF, and that turbo will run all day long and with expected longevity at that TIT. He went on to say that Mooney (not Hartzell) lowered the max TIT to 1650dF at altitude to increase detonation margin due to the higher and unmonitored compressor discharge temps at altitude. Ah ha! I get that! So I said that I monitor CDT and Inlet Air Temp and at higher altitudes I can see little difference than in the mid teens so I suspect my detonation margin is not changing based on CDT, right? To which he replied: because you monitor those parameters you will know if your intercooler is working properly or not, you (me) should be able to safely ignore that lower TIT limitation as long as the CDT remain low and reasonable. Interesting - so what about metal fatigue? His answer was simple - we design the turbo to withstand and tolerate that max TIT of 1750 and there is a adequate safety margin there for metal fatigue and blade stretch. We don’t want these units coming back for repair, so we set the max operating parameters with care. So the take away is, if you trust the manufacturer, then our collective arguments of running TIT lower than allowable to “protect the turbo” is largely flawed. So what about the rest of the exhaust system? Some argue that this is the weakest part of the mooney’s engine and by running TiT less than max you will preserve the exhaust components. Maybe - likely - but no one can really say for how long or in what consistency owner-to-owner. But more importantly, TiT is not directly representative of the “rest of the exhaust system”. TiT is higher than individual EGT’s because it represents the additive effects of the pulses of heat collecting at one point AND under increased pressure at the entrance to the turbine hot side. Before that inlet, the individual EGTs are cooler (some can be 100dF cooler ) and after the turbo, the aggregate exhaust is at least 100dF cooler. On my Bravo I have a second TIT probe (TOT actually) at the exit of the turbo just past the V-clamp. I added that to monitor for a (unlikely) sudden failure of that section and it's always 125dF lower than real TIT. What this says to me is that if you are running the max TIT of 1750, you will be likely be 1650 or less in the main exhaust system. If you run 1650 max TIT then the math works out to be 1550 or less EGT and that is where we find most non-turbo systems running at decent power levels. Happily I might add. Some may argue that you’ll burn probes out faster at higher temps. Probably, but again how much faster? I think Mooney recommendation is to replace the TIT probe at 200 hours regardless, but I think that’s overdone as well. Thermocouple probes have gotten way batter in just the last decade, so they are lasting longer and staying accurate for a longer period of time. All that said - we agree that cooler is better, so run your engine where you want. But I would suggest that we should not be afraid to run the power up and go fast while not exceeding the limits, and also not being shy of approaching them. OK, let me have it! :-)
  5. I think we all need to be careful before jumping to conclusions here. Fuel tanks repairs and reseals have used various manufacturers' Buna-N for decades now under the influence of 100 LL without known issues. Mooney, still to this day, prescribes the use of Buna sealants in the fuel section of the official maintenance manual. There are easily a number of potential confounding factors here that could have cause Mattbucy's problem. And thank goodness he was able to land safely to talk about it. I am making calls today to both PPG and Flamemaster and I'll share any new info I get.
  6. Fuel Cell Reseal DVA

    Very nice words, Brian, thank you from all of us here! Shout out to Paul at Weep No More who has been very helpful and is always willing to answer questions. Paul is the the foremost expert in this process, and if you're in his neck of the woods that's where I'd go. The folks at Wet-Wingologists in Florida and of course Don Maxwell in CA are both known for excellent work and customer service as well. There are others. Best news is that there is a community of people who care about Mooney's and will provide them and their owners with proper and quality care. Fly safe!
  7. Odd. What convinced you that one side of your engine was not firing while the other side was?
  8. Aircrafts ?

    Or run out into the streets and get hit by a few car.
  9. ISO ADSB Suggestions

    Hi, An option is to send the 330 to Garmin and have them upgrade it to 330ES for adsb-out, you likely need to add a few wires from the 650's Data buss to the 33O connector to pull in/out GPS data. Do a 91.413 check, fly in controlled airspace, get your FAA report and enjoy.
  10. Here's a video I did for the Garmin AoA, but you can hear the P2 system as well. I didn't install it, it came with the plane but it never falses nor is it annoying - only helpful.
  11. My first ever 'for real' go around

    Almost 40 years ago when I was getting my PP my instructor refused to let me practice landings until I was able to do perfect go around from every conceivable situation. I remember my first landing as a result of his commitment to teaching me the importance of being very good at that maneuver. I can hear him saying to this very day "a go around is not an emergency procedure - it's a procedure to keep you from having an emergency". Good times.
  12. Fuel Flow Issue

    Hi, Two questions - 1) did toggling on/off the electric boost pump change the fuel pressure/flow at altitude? 2) was the fuel flow drop off gradual as you climbed, or did it drop off quickly at from normal at 7000'?
  13. In need of a mechanic in Pennsylvania (KDUJ)

    Here's a quick opinion just to start a little trouble. Lawn mowers to airplane engines, save the modern automobile engine, all break in (or not) the same. Its all about how you run the engine in the first hour and then in the next 10 or so. Do this wrong, and it doesn't matter what oil you used.
  14. In need of a mechanic in Pennsylvania (KDUJ)

    Actually AD oil will work too, albeit slower when compared to MO. Lycoming wants all turbo engines to to break in with AD to favor the proper lubricating properties needed for the turbo.
  15. In need of a mechanic in Pennsylvania (KDUJ)

    Truls, for non turbo engines always run mineral oil and fly it hard. The #1 reason for a poor or in incomplete break-in is babying the engine during the first 10-25 hours.