M20 C unusable fuel quantity?

[Urs_Wildermuth]

Folks,

 

a question if I may. I got the original manual of the 65 Mooney M20 C which corresponds to my aircraft. Yet, there is no mention of the unusable fuel quantity, only the total quantity of 52 USG. Likewise, the manual uses 52 USG for range calcs.

So is it so that there is no unusable fuel quantity in those tanks? Or is it documented elsewhere?I have heard figures of 2 USG each, which would leave 48 USG, but I can't find this in writing.

Any inputs are appreciated.

[Gone]

Urs:

It is located on page 10 of the Mooney Type Certificate (2A3), second last entry at the bottom of the page.  It states the useable fuel quantities depending on the serial number of the aircraft.

The Type Certificate is published on the FAA website at http://www.google.ca/#sclient=psy&hl=en&source=hp&q=mooney type certificate&pbx=1&oq=mooney typ&aq=1v&aqi=g1g-v2g-j2&aql=&gs_sm=sc&gs_upl=1119l3202l0l5456l10l10l0l1l1l0l251l1634l1.3.5l9l0&bav=on.2,or.r_gc.r_pw.&fp=548cb621829ee2a3&biw=1173&bih=611&pf=p&pdl=300.

I thought the EASA might have a copy of it, but they only have copies of the parts related to M20Ms and later.

Hope this helps.

[Piloto]

The usable quantity is 52 gallons total. The unusable amount is no more than 1/2 gallon per side. The total fuel that can be loaded varies with the way the air plane is leveled on the ground. Some of the early Mooneys using the thermo bottle caps are placarded 48 gallons due to the cap being recesed lower.

José

 

[Urs_Wildermuth]

Hi Ned and José

thanks for the fast reply.

I went into the document. Mine is SN 3269, therefore 52 USG fully useable. Note 1 (on page 49) states that unusable fuel for the "C" is 3.4 lb but included in the Empty Weight!

Good to know. I notice that there is considerable confusion around on the subject. The checklist I inherited with the plane sais 48 USG useable, which is proven wrong now.

 

[DaV8or]

I guess you might have to fill a tank up, run it dry and refill it to be really sure how much is usable.

[Urs_Wildermuth]

Dave,

might well amount to it. Peter Garrison sais 50 USG usable in his book.

what do you calculate with your "F"? 64 USG?

[DaV8or]

Quote: Urs_Wildermuth

Dave,

might well amount to it. Peter Garrison sais 50 USG usable in his book.

what do you calculate with your "F"? 64 USG?

[Hank]

Just checked my Owner's Manual, 1970. Found the following quotes:

p. 1-5  General Description, Fuel System:  Useable Fuel.........................52 gallons

P. 2-5  Systems Operations, Power Plant, Fuel System  Full fuel capacity is 52 gallons.

p. 4-9  Aircraft Limitations & Operations, Operating Procedures, Normal  To preclude fuel starvation, avoid extreme sustained side slips toward the takn in use when that tank contains less t han 36 pounds of fuel.

p. 6-8  Performance, Cruise & Range Data Conditions  [full power climb, full rich, no wind, etc.] The data is also based on 52 gallons of useable fuel.

So apparently my plane has 52-gallon capacity, and it is ALL USEABLE.  ???

Also of interest, I found THESE two fuel statements:

p. 4.4, Aircraft Limitations & Operations, Power Plant  Fuel........................100/130 octane aviation gasoline

       [what we've all been told, and I use 100LL]   BUT

p. 7-4  Servicing, Refueling   ... With the aircraft standing on level ground, service each fuel tank after flight with 91/96 octane aviation-grade gasoline.

So I DON'T have to use 100LL??? Or I do??? The durn book says both . . . I'm "limited" to 100/130, but am supposed to "service" the aircraft after flight with 91/96. Hmmmmmmm . . . . .

[carusoam]

 

Hank,

 

Just checked my M20C POH.  It is in agreement with yours.  For S/N 20-1186 and on....52 gal usable.  26 on each side.

 

If you have the official W&B from when new, I suspect you may find the unusable weight of fuel and some amount of oil in the "empty" weight of the plane.  

 

Best regards,

 

-a-

[sleepingsquirrel]

Quote: Hank

Just checked my Owner's Manual, 1970. Found the following quotes:

p. 1-5  General Description, Fuel System:  Useable Fuel.........................52 gallons

P. 2-5  Systems Operations, Power Plant, Fuel System  Full fuel capacity is 52 gallons.

p. 4-9  Aircraft Limitations & Operations, Operating Procedures, Normal  To preclude fuel starvation, avoid extreme sustained side slips toward the takn in use when that tank contains less t han 36 pounds of fuel.

p. 6-8  Performance, Cruise & Range Data Conditions  [full power climb, full rich, no wind, etc.] The data is also based on 52 gallons of useable fuel.

So apparently my plane has 52-gallon capacity, and it is ALL USEABLE.  ???

Also of interest, I found THESE two fuel statements:

p. 4.4, Aircraft Limitations & Operations, Power Plant  Fuel........................100/130 octane aviation gasoline

       [what we've all been told, and I use 100LL]   BUT

p. 7-4  Servicing, Refueling   ... With the aircraft standing on level ground, service each fuel tank after flight with 91/96 octane aviation-grade gasoline.

So I DON'T have to use 100LL??? Or I do??? The durn book says both . . . I'm "limited" to 100/130, but am supposed to "service" the aircraft after flight with 91/96. Hmmmmmmm . . . . .