Mooney Aircraft Accident Nampa, ID

[DCarlton]

1 hour ago, Shadrach said:

It would be interesting to see where it peaks. To my way of thinking, full rich mixture at max power should be ~250° ROP. It seems unlikely to me that your peak EGT is in the high 1500s but I could be wrong.  You’re not going to hurt anything leaning to peak at low altitude for a brief period. It would be good to know how rich your engine is at high power with the mixture firewalled. I’m not suggesting that you need to change anything if it turns out that it’s only 200° ROP, only that it’s good to know what it’s doing so you can act accordingly.

Don't think I've ever seen anything in the 1500's.  I believe peak is in the mid 1400's.  I'll record more data when I get a chance.  Gonna put a sticker on the panel with the EGT at sea level takeoff power for future reference.  

[EricJ]

2 hours ago, Vance Harral said:

Noted, thanks for the additional info.  This is not what I recall from the few times I've actually tried a full-power runup in a constant-speed-prop airplane, but entirely possible I'm mis-remembering.

Yes, most airplanes with constant speed props should make redline in a static runup.   An airplane with a fixed-pitch prop will usually have a minimum static rpm specified somewhere in the airplane documentation (POH, AFM, SMM, whatever).

[Hank]

1 hour ago, DCarlton said:

Don't think I've ever seen anything in the 1500's.  I believe peak is in the mid 1400's.

My C generally peaks ~1450°F, depending on conditions. 

[Ragsf15e]

6 hours ago, DCarlton said:

Gathered some data yesterday.  I'm seeing 1320 deg from 330 feet at CRQ although I failed to record the OAT.  It was definitely hotter than a standard 59 degrees.  Not sure if that makes much difference.  Will gather a few more data points; then likely target EGTs between 1220 and 1320 in high DA conditions.  I'm now curious if 1220-1320 will correspond well to a smidge of a turn ROP from rough (the ole school way).  

I used ~1250 in my F for target egt.  Worked very well.  When I arrived at cruise, that egt corresponded to ~150-200 ROP.  So probably richer than the "old school" way which is what you'd want for climb, but it's too rich for cruise.  Once you know that target egt, it makes leaning in the climb simple all the way up.  Just be advised that a little change in mixture can make a big change in your chts on the way up.  So if you find 1250 works well, but you try 1300 on a warm day, you might see some hot CHTs.

[Shadrach]

7 hours ago, Vance Harral said:

Peak indicated EGT in our M20F with an EI UBG-16 monitor and P-110F probes located about 8" down form the header runs between 1550 and 1575.  I've been in other airplanes where peak EGT is well over 1500, I don't think it's particularly unusual.  But lots of other airplanes I've flown peak in the 1400s.  My experience is there's a lot of variation, but I don't have thousands of data points, only dozens.

I am not surprised that you’ve encountered different peak EGT ranges in different aircraft. All other things being equal, raw peak EGT number is influenced heavily by compression ratio. Greater thermally efficiency = lower EGT number.  The number by itself is not really meaningful, but it can give you a clue when it does not make sense as relates to peak.
 

 

[Shadrach]

13 hours ago, EricJ said:

Yes, most airplanes with constant speed props should make redline in a static runup.   An airplane with a fixed-pitch prop will usually have a minimum static rpm specified somewhere in the airplane documentation (POH, AFM, SMM, whatever).

I’ve was told by my prop shop that the blade should be against the fine pitch stop during static run up and and that making red line static is not always possible. 

[Ryan ORL]

On 8/2/2025 at 10:50 PM, Shadrach said:

Completely agree that target EGT is the best approach.  I’m of the opinion that an EGT of 1200°-1250° is a more ideal target for an IO360 with an 8.7 to 1 C/R.

I target 1250 with mine also.  Any higher and the CHTs are unacceptable.

[EricJ]

5 hours ago, Shadrach said:

I’ve was told by my prop shop that the blade should be against the fine pitch stop during static run up and and that making red line static is not always possible. 

Whatever it says in the POH/SMM/AFM etc.   The M20J SMM says that the static rpm may be 50 rpm less than 2700 rpm, so that's basically the allowed tolerance less than redline.

[Schllc]

On 8/3/2025 at 7:04 AM, Fly Boomer said:

I wonder if the later airplanes have some sort of bracket welded into the tubing?

The later models do indeed have a bracket and a stiffener welded to the frame, but  it is still a rather small thin wall tube…

That being said, it’s a chromoly cage vs aluminum in most planes…

[1980Mooney]

On 8/3/2025 at 6:04 AM, Fly Boomer said:

I wonder if the later airplanes have some sort of bracket welded into the tubing?

 

56 minutes ago, Schllc said:

The later models do indeed have a bracket and a stiffener welded to the frame, but  it is still a rather small thin wall tube…

That being said, it’s a chromoly cage vs aluminum in most planes…

There doesn't appear to be a stiffener.  It just appears to be a bracket welded to the tubular.  Only a bracket is shown in the parts diagram - no separate stiffener is shown.

Here is a J pilot seat shoulder attachment point.

Here is a Long Body which would show any later model change.  The Pilot and back seat shoulder harness attachment points are shown.  You can see the simple bracket.

And here is the parts diagram for the S and R.  Only a bracket is shown - #63 Copilot and #71 Pilot shoulder harness attachment point.  The Acclaim parts manual shows the same. 

Interestingly they don't even show the back seat shoulder harness welded on brackets; however, they clearly exist in the picture of the Long Body frame. 

 

 

Edited August 10 by 1980Mooney