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About Gary0747

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  1. Gary0747

    True airspeed not what book says

    With the current mags does anyone know the tolerance limit in btc setting before having to change mags for 25btc operation? I vaguely remember something like 20 degrees plus or minus two degrees but don’t remember where I got this.
  2. That photo of the 110-773 antenna does not appear to be able to bent over to fit under the dorsal. This drawing of a 110-773 is a very different antenna and appears to be able to bend and fit. That is, look at the difference in height of the loading coil on the bottom.
  3. The thing that confuses me about finding the antenna recommended to install in the dorsal according to Mooney SIM20-116 is there appears a large number of different antennas styles with the same model number Airtex 110-773. Even talking to a MSC and several different vendors didnt clarify anything. No one knew about a revision (B) The MSC said they use the standard antenna that come with the Airtex ME-406 that Spruce carries. I would order one to see but the items are not returnable. I am looking for anyone who has done the 121.5 to 406 upgrade in their dorsal for advice.
  4. Hello all,

    I’m preparing to purchase a 69 Moony M20F.  Does anyone have a mechanic you can recommend whom specializes in Mooney’s in Orange County, CA?



  5. Gary0747

    True airspeed not what book says

    That curve would really take the wind out of the sails of all the folks promoting the HP gain from electronic ignition. I bet you would have to change the engine data plate before you could convince your IA to sign off 25 deg btc at annual time. When I got my 67F back in 1992 it had a 1000 hour engine with the 25 degree data plate. I think it was an early 80s overhaul.
  6. Another thing worth noting here is not all ELTs sold now are dual band. Both 406 and 121.5 MHz made more sense a few years ago but with 121.5 no longer being satellite monitored and the old single band 121.5 equipment no longer being sold the future viability of dual band units is diminishing. So apparently dual band transmitters and antennas are not required in the regs?
  7. It all dependes where you crash and assumes you are not upside down. Vertical antennas have their transmitting radiating lobes perpendicular to the antenna which makes the straight up direction weakest. Perhaps if you are not in a ravine you can hit a satellite in a somewhat horizontal direction. Anytime any kind of transmitter is installed hooked to a new antenna a simple SWR/Power check should be made to prevent the reflected power from damaging the finals and make sure adequate power is being radiated.
  8. The current antennas are apparently vertical but dont have to be quarter wave. It is hard to say what the radiation pattern is when they are bent over sideways when put inside the dorsal fin like Mooney does. If the objective is to put out a signal upward towards a sattelite it seems a vertical antena would be the least effective.
  9. The service instruction gives two locations for mounting inside the dorsal and outside the dorsal. It specifies the (B) version antenna for the inside the dorsal fin. The inside the dorsal fin will only work if you have a plastic dorsal fin. My fin currently is metal but I just ordered the Laser speedmod dorsal which is currently on sale and it is plastic.
  10. It would be easy to make a dipole antenna for 406 MHz and mount it inside the plastic dorsal fin, but I was wondering about the legalities of making your own? Half wave dipoles have more gain than vertical quarter wave antennas so it seems to make sense to go this way. I had a PM from a person with a link to a dual band vertical saying that Mooney uses that antenna. If they mount it inside the plastic dorsal they must not be mounting it vertically? Vertical antennas have to work against a metal or conductive ground plane so if Mooney or Cirrus has figured out how to do this it would be nice to know.
  11. For those that have the plastic Dorsal fin has anybody found a dipole ELT antenna that would mount inside it? Paul Lowen used to talk about doing this back with the old 121.5 MHz ELT and with his dorsal fin speed mod. I was looking for a 406 MHz dipole that would fit inside the dorsal. I think internal ELT antennas are done in plastic and fabric airplanes. Not sure where Cirrus puts theirs?
  12. Gary0747

    How Reliable is JPI EDM900?

    Perhaps the EDM 700 or 800 is the most reliable way to go even though it is almost 20 yr old technology and actually costs more currently than the EDM 730/830. I have read of very few problems with them. I agree with Marauder on EI potentially being more reliable but I just can’t bring myself to having to purchase and install two units to cover all my primary functions
  13. In reading several of the old threads I see that a number of people have had problems at times that have even required sending their EDM900 units back to the factory. This being a primary instrument also means their aircraft is out of service. I am debating the merits of making the leap all the way to the EDM900 when the EDM830 has almost all the functions and is not a required for flight instrument. I have a working reliable set of primary gauges and am not in a bind for panel space now. It almost seems like the EDM830 is the safest way to go, plus it is almost half the price. I would appreciate any experienced advice?
  14. Gary0747

    True airspeed not what book says

    On the IO360 the timing was 25 deg btc back when the books were made. Lycoming got nervous about detonation and reduced the timing several degrees. They may have done this on the 0360 also. I asked the Lycoming rep once how they could still say these were 200 hp engines. He said the stated numbers are only accurate to within 5 percent.
  15. Gary0747

    AD 77-17-04 Control Wheel Inspection

    I obtained the heavy wall shaft for the pilot side that is not subject to the AD years ago. I still need the one for the copilot side to get clear of the AD. Seems ridiculous since very little time is spent flying from that side. If anybody knows a source for the heavy shafts now,please let me know.