warrenehc Posted March 10, 2021 Report Posted March 10, 2021 Hello everyone, I am sorry for asking this question, but I have conflicting information. What I always believed/ understood was that the F model 1967 had 2.5gal of unusable fuel. With a 64 gallon fuel capacity. I just purchased my new to me Mooney and when reading the POH it said it has 64 gallons of useable fuel. In no other place in the POH does it have any other number besides 64 gallons. So is the fuel capacity 64 and can use it all? Does it have 66.5 gal capacity and can use 64 gal? Or is it really 64 capacity and you really can use 61.5? I’m sorry for asking, I just want to know for planning and safety margin.
Pasturepilot Posted March 10, 2021 Report Posted March 10, 2021 It’s buried in note 1 at the very end of the TCDS. 15 lb. unusable
Greg Ellis Posted March 10, 2021 Report Posted March 10, 2021 Not to hijack this thread but 48 lbs of unusable fuel for certain K models? That is roughly 8 gals of unusable fuel? Seems like a lot. Nice to see that my little old C model only has about 1/2 gal of unusable fuel (3.4 lbs).
gsxrpilot Posted March 10, 2021 Report Posted March 10, 2021 My 252 is only about 1/2 gal unusable per side.
David Lloyd Posted March 10, 2021 Report Posted March 10, 2021 The Executive Operators Manual lists the useable fuel at 64 gallons. The unuseable would be more, see the TCDS quote from pasturepilot. Unless you have bladders installed, then something different. In my C, the Operators Manual lists the useable fuel at 52 gallons. The TCDS shows 3.4 pounds being unuseable. But with bladders installed, according to the STC paperwork and flight manual supplement, it now has 57.3 total gallons capacity, 54.8 gallons useable, 2.5 gallons unuseable. When the airplane was reweighed last year, All fuel was completely drained, then 1 1/4 gallons per side were added and then weighed. Later I ran the engine at idle on the unuseable fuel. Ran for 10 or so when I noticed the fuel pressure gauge on 0. I turned the boost pump on and the pressure came back up for about another minute before I shut it down.
RobertGary1 Posted March 10, 2021 Report Posted March 10, 2021 (edited) It’s just checkride trivia found in the maintenance manual. Nothing a pilot needs to know. Empty weight already includes it. you have 64 gal usable until dry. Useless fuel is to collect sediment and won’t be picked up by the fuel system. Edited March 10, 2021 by RobertGary1 2
David Lloyd Posted March 10, 2021 Report Posted March 10, 2021 I got a flight review and IPC from a new instructor a couple months ago. I think he asked me around 10,000 questions. Some of which were pretty good, made me think back about 40 years. 1
carusoam Posted March 11, 2021 Report Posted March 11, 2021 Great question Warren... There is a real answer that goes with that... No matter what the book says, or the decals on the instrument panel, or the sticker on the wing... (placards for the MS aficionados...) The only way to know for sure what the useable fuel is for your plane... Is to measure it... There is plenty of that methodology covered for all new owners... often while they are making a calibrated stick... Do it once, get it over with... the data is good for the rest of your plane’s life... To get a feel for how much unusable fuel is in there... when the tank is low... get a pic of the fuel pick up screen... the top of the screen is where the unusable begins... that is the point where air starts entering the fuel line... Where the unusable fuel ends... find where the fuel sump is... there is about a cup of fuel that can hide below that hole... or water depending on how well you keep your tanks dry... It becomes a really important piece of information... when you are fighting headwinds... PP thoughts only, not a mechanic... Best regards, -a-
M20F Posted March 11, 2021 Report Posted March 11, 2021 I once put 62.5 gallons in my F after a flight.... 1 1
Tcraft938 Posted March 11, 2021 Report Posted March 11, 2021 20 hours ago, David Lloyd said: I got a flight review and IPC from a new instructor a couple months ago. I think he asked me around 10,000 questions. Some of which were pretty good, made me think back about 40 years. Maybe he was about to do his instructor checkride and he asked you the 10,000 questions so he could have answers for his ride. :-) 1
N201MKTurbo Posted March 11, 2021 Report Posted March 11, 2021 2 hours ago, M20F said: I once put 62.5 gallons in my F after a flight.... I’m not sure I’d brag about that... 5
M20F Posted March 12, 2021 Report Posted March 12, 2021 5 hours ago, N201MKTurbo said: I’m not sure I’d brag about that... It was a statement. 1
MikeOH Posted March 12, 2021 Report Posted March 12, 2021 9 hours ago, M20F said: I once put 62.5 gallons in my F after a flight.... I plan never to make such a statement.
M20F Posted March 12, 2021 Report Posted March 12, 2021 1 hour ago, MikeOH said: I plan never to make such a statement. The internet and aviation are filled with people who all have a plan till they get punched in the mouth. PS The original post is a typo, should read 64.5 gallons. 3
Andy95W Posted March 12, 2021 Report Posted March 12, 2021 4 hours ago, MikeOH said: I plan never to make such a statement. 2 hours ago, M20F said: The internet and aviation are filled with people who all have a plan till they get punched in the mouth. Exactly. 30 years and a whole bunch of hours ago I put 39.4 gallons into a C-172 that held 40 gallons total. After a night flight. Because I was stupid enough to listen to a guy just because he was a King Air pilot. We live, we learn. If we’re lucky, we survive our mistakes so that we don’t repeat them. 2
ncav8tor Posted March 20, 2021 Report Posted March 20, 2021 On 3/11/2021 at 11:28 AM, M20F said: I once put 62.5 gallons in my F after a flight.... You got robbed Brother! That pump meter was off a bit LMAO, just kiddin with ya!
cliffy Posted March 21, 2021 Report Posted March 21, 2021 Unuseable fuel and its moment are included in empty Weight and CG. On the other hand- Any CAR-3 airplane does NOT include the weight of the engine oil in the empty weight of the airplane so the weight of the oil in the engine comes off of your useful load. On Pt 23 airplane FULL engine oil is figured in to the Empty Weight calculations.
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