Looking at Mooneys (M20E particularly)

[madjano]

Ya full tanks to empty pretty much straight up and down on the plot. That was a big reason going Mooney over old Bo.
I can tell u load up the luggage compartment in the E. I am amazed how much better cruise speeds are.

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[takair]

14 hours ago, zaitcev said:

I think we can be (almost) certain that my calculations are good. However, the inputs are very much suspect. If you could share your empty CG and the stations that you use, it would be very helpful.

The ship's empty CG is 42.71" with 1695.4 lbs. What catches the eye immediately is that the weighting was done with full tanks, and the directly weighted CG was found at 43.59".

Fuel 48.43", front seat 39" (and that is with seats in rearmost positions - I'm 6'5" and I fly on the last available position hole). These are most vexing ones. Rear seat at 70.7" and baggage at 95.5" are empty.

Remember that the corners of the envelope are 42" at 2100 and 46.5" at 2575 lbs. So, for a pilot of 230 lbs, such as myself, and a passenger of 190lbs, we end at 41.98" - just in front of the front corner. Adding full fuel pushes us way out: 42.75" at 2427.4 lbs. Basically, the only way to carry a passenger in this M20E is to fly with 1/4 tanks and put 10 jugs of water in baggage compartment.

Something seems way off.  My empty CG (with oil) is 45.7 at 1671.9 lb.  The pilot seat range is listed at 36.5 to 44.0, so that too seems to be off if you have 39" as the aft position.  39" is the nominal position.  I would be suspicious of the weighing of your aircraft.  Did they have it level at the time?  It also depends on what your gear was doing (compression of pucks) it shifts the center of the axles significantly and that will shift your CG significantly.  Do you know if this was measured at the time of weighing and calculated that way or did they try to use the original chart?  Were the scales calibrated?  While weighing the aircraft would intuitively seem like a more accurate representation of weight than calculation, if it is not done precisely you can be living with large errors.  I am not that much lighter than you and often fly with equally large folks and don't have to ballast the aircraft.  It may be worth a re-weigh or go back to day one and run the numbers.  I have a rather complete spreadsheet if you need a short-cut.  This would give you a sanity check of the weighing. 

[Bob_Belville]

2 hours ago, takair said:

Something seems way off.  My empty CG (with oil) is 45.7 at 1671.9 lb.  The pilot seat range is listed at 36.5 to 44.0, so that too seems to be off if you have 39" as the aft position.  39" is the nominal position.  I would be suspicious of the weighing of your aircraft.  Did they have it level at the time?  It also depends on what your gear was doing (compression of pucks) it shifts the center of the axles significantly and that will shift your CG significantly.  Do you know if this was measured at the time of weighing and calculated that way or did they try to use the original chart?  Were the scales calibrated?  While weighing the aircraft would intuitively seem like a more accurate representation of weight than calculation, if it is not done precisely you can be living with large errors.  I am not that much lighter than you and often fly with equally large folks and don't have to ballast the aircraft.  It may be worth a re-weigh or go back to day one and run the numbers.  I have a rather complete spreadsheet if you need a short-cut.  This would give you a sanity check of the weighing. 

+1

You should not be at the forward CG limit in an E.

My '66E empty is 1675.5# @ arm 47.4". With rear seat passengers & luggage I flirt with the 49" rear limit. I have several avionic boxes in the rear. Fortunately, I am only 5'8" and use the 2nd or 3rd hole from the front. My front seats have arms from 36.5-44".

[zaitcev]

16 hours ago, mooniac15u said:

First, the TCDS lists the front seat rearmost position at 44.0" and the baggage area at 93".

I see. Thanks for the tip. I downloaded the TCDS 2A3 and found the right numbers. It's still pretty tight though, almost exactly like Cherokee of the similar vintage, but at least I can get half fuel with the passenger now.

[zaitcev]

3 hours ago, takair said:

Something seems way off.  My empty CG (with oil) is 45.7 at 1671.9 lb.

Yeah, if mine were so far back, it would not be a problem. It's possible that it was not weighed correctly. I have an annual coming up next month, and I'll bring the matter up with my mechanic.

I should note that my M20E is a Chapparal, with 200 mph Vne. Possibly the structure is somewhat different from a garden variety E.

Edited March 25, 2017 by zaitcev

[mooniac15u]

16 hours ago, zaitcev said:

I see. Thanks for the tip. I downloaded the TCDS 2A3 and found the right numbers. It's still pretty tight though, almost exactly like Cherokee of the similar vintage, but at least I can get half fuel with the passenger now.

Did you run a calculation with just full fuel (no pilot or passenger) to see if your result is the same as the W&B from the weighing?

[HRM]

On 3/24/2017 at 0:33 PM, MyNameIsNobody said:

You putt putters make me laugh.  Go farther faster...or Putt Putt.

This was my LOL for the day.

When I was plane shopping I started by looking at the E I now own and decided too pricey and too much work (interior and panel were yuck).

Then I moved to an Ercoupe. I liked the idea that Mooney had a finger in that pie and the thought of pushing back the canopy and cruising around was enticing. Then I thought--hey, the term 'cruising' really points to speed, the 'coupe is a 'putter'.

Then I turned to aerobatics and began lusting after an Aerobat. The thought of flying along and then pulling a barrel roll at whim was intoxicating. I went to Florida and flew an absolutely gorgeous 'bat that was being sold parachutes included. Then I thought about all the trips I had planned and a 'bat is still a 150 putter aerobatics or not.

I came back to the E and never looked back afterward--absolutely not a putter and criminal to be flown that way.

[Bob_Belville]

20 hours ago, zaitcev said:

Yeah, if mine were so far back, it would not be a problem. It's possible that it was not weighed correctly. I have an annual coming up next month, and I'll bring the matter up with my mechanic.

I should note that my M20E is a Chapparal, with 200 mph Vne. Possibly the structure is somewhat different from a garden variety E.

My '66 M20E (Super 21) has a Vne of 189 mph. I did not realize they had changed Vne in later years. What else might have changed?

Vne 189 mpg;

Vno 150,

Vfe 100,

Vs 67,

Vso 57,

Vlg 120,

Va mgw 132, Va 2200# 122,

Vx (t.o. flaps) 80,

Vy clean 105,

Vg mgw 105, Vg 2200# 97,

V window 150 

[Hank]

2 hours ago, Bob_Belville said:

My '66 M20E (Super 21) has a Vne of 189 mph. I did not realize they had changed Vne in later years. What else might have changed?

Vne 189, 200

Vno 150, 175

Vfe 100, 125

Vs 67,

Vso 57,

Vlg 120,

Va mgw 132, Va 2200# 122,

Vx (t.o. flaps) 80, 85

Vy clean 105, 100

Vg mgw 105, Vg 2200# 97,

V window 150 

Bob--

I put the numbers for my 1970 C above in red where they are different. Electric gear and flaps. I don't remember what Vg stands for . . . But I probably know the number. Best Glide is 105 mph. Stall is 64 mph clean, down to 54? with full flaps. Vy is 100 mph minus Altitude in thousands. Lots of changes through the late 60s.

[Hank]

Just now, Hank said:

Bob--

I put the numbers for my 1970 M20-C Ranger above in red where they are different. Electric gear and flaps. I don't remember what Vg stands for . . . But I probably know the number. Best Glide is 105 mph. Stall is 64 mph clean, down to 54? with full flaps. Vy is 100 mph minus Altitude in thousands. Lots of changes through the late 60s.

 

[Bob_Belville]

5 hours ago, Hank said:

Bob--

I put the numbers for my 1970 C above in red where they are different. Electric gear and flaps. I don't remember what Vg stands for . . . But I probably know the number. Best Glide is 105 mph. Stall is 64 mph clean, down to 54? with full flaps. Vy is 100 mph minus Altitude in thousands. Lots of changes through the late 60s.

Vg is best glide. Note it varies with weight.

Thanks for the other numbers. The 3 speeds that increased would be nice to have. Vne - red line, Vno - bottom of the yellow, and Vf - max flap. As it is I often cruise in the yellow, descend at red line, and cannot use flaps until into base leg.

[adrian]

I'd also love to increase the Vne and Vno numbers.  I've never been able to find out if there was actually any change to the structure, or if it was just a paperwork change.  Does anybody know?

[Hank]

Rudders are different, all the way bel I w the stab to the bottom of the fuselage. Flaps mount differently, the sub spar changed. What else? I dunno.

[Bob_Belville]

31 minutes ago, adrian said:

I'd also love to increase the Vne and Vno numbers.  I've never been able to find out if there was actually any change to the structure, or if it was just a paperwork change.  Does anybody know?

There are several threads here asking these questions. There are several answers but I don't think I've seen anything I'd call definitive. I try to live within the proscribed limitations with the caveat that there is probably a margin for error if I get some bumps while in the yellow or find myself at 90 kias on base after putting in partial flaps. I've heard of folks who might take off in an E @ 2700#.

[zaitcev]

12 hours ago, adrian said:

I'd also love to increase the Vne and Vno numbers.  I've never been able to find out if there was actually any change to the structure, or if it was just a paperwork change.  Does anybody know?

Larry Ball's book is not very helpful. All it says is the following.

About M20F:

"The 10-inch increase in cabin length... Fuel capacity was increased from 52 gallons to 64 gallons, and gross weight was increased to 2,740 pounds, up 165 pounds over the M-20E Super 21's 2,575 pounds."

About Chapparal:

"The Chapparal was essentially a 1968 M-20F Executive shortened back to its original fuselage length... Fuel capacity was reduced from 64 gallons to 52 gallons. It did have new electric flaps, and electrically operated gear was standard equipment. ... Flap extension speed was increased from 87 knots up to 119 knots. Best of all, the airspeed caution arc was moved from 130 to 152 knots."

So, I can conclude that all the control surfaces are better attached and possibly stiffened or have different anti-flutter weights. It is also possible that Chapparal would operate at higher gross weight, with a corresponding increase in stall speeds. May be useful for a ferry. But that's about it. I would really like to know what was the actual difference in the structure.

[outermarker]

This example is using the back seats for luggage as well as baggage compartment. Camping gear to OSH or Sun n' Fun!

1965 Mooney E Weight & Balance.xls

Edited April 20, 2017 by outermarker

[DXB]

On 3/23/2017 at 11:46 AM, Godfather said:

I think the manual gear shines with old planes that sit a lot. If I had to choose between two 50 year old planes that have only 3k hours I'd prefer the mechanical operated unit. If the two planes were 20 years old with the same number of hours I'd go for the electric unit every time. 

If only I could find a 20 year old Mooney with a J Bar.  This mythic beast is my dream aircraft.