Raise your useful load without an STC...

1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the usual 6
lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Hilton

On Thu, 02 Aug 2007 07:34:53 GMT, "Hilton" wrote:

1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the usual 6
lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Hilton


It's valid, or at least more accurate that the traditional 6 lbs/gal.

Fuel specific density probably varies between manufacturers, but is
usually specified as 0.7 or 0.71, which is about 5.84 lbs/gal.

You need to carry a lot of fuel for this difference to amount to
anything useful.
I'll keep using the more conservative "6", ... and start dieting

- Tom

Hilton wrote:
1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the usual 6
lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Yes, diets are completely legal and valid and most of us should do so.

Mooney didn't "define" a gallon of 100LL to weight 5.82 lbs, that is
what it DOES weigh. Someone else "defined" it as 6 lbs many moons ago
to simplify calculations. If Mooney is doing as you say (I didn't take
time to verify), then they are just being more precisely correct, if
more impractical for their pilots.


Matt

Matt Whiting wrote:
Hilton wrote:
1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the usual
6 lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Yes, diets are completely legal and valid and most of us should do so.

Mooney didn't "define" a gallon of 100LL to weight 5.82 lbs, that is
what it DOES weigh. Someone else "defined" it as 6 lbs many moons ago
to simplify calculations. If Mooney is doing as you say (I didn't take
time to verify), then they are just being more precisely correct, if
more impractical for their pilots.


Matt
For 50 gallons of fuel the difference is 9 pounds. Not much of a
difference as most peoples weight can change 4 pounds in a day based on
time of day and water in/out

Matt,

According to Wikipedia: "Avgas has a density of 6.02 lb/US gallon at 15 °C".
Not sure how 'correct' this is.

Hilton


"Matt Whiting" wrote in message
news
Hilton wrote:
1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the usual 6
lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Yes, diets are completely legal and valid and most of us should do so.

Mooney didn't "define" a gallon of 100LL to weight 5.82 lbs, that is what
it DOES weigh. Someone else "defined" it as 6 lbs many moons ago to
simplify calculations. If Mooney is doing as you say (I didn't take time
to verify), then they are just being more precisely correct, if more
impractical for their pilots.


Matt

On Aug 2, 8:54 am, "Hilton" wrote:
Matt,

According to Wikipedia: "Avgas has a density of 6.02 lb/US gallon at 15 °C".
Not sure how 'correct' this is.


One of the material data sheets at Shell's website says their 100LL is
0.718 kg/L at 15 C.
http://www.shell.com/static/au-en/do..._100ll_pds.pdf

0.72 kg/L is 6.02 lb/US gallon.

I guess it depends on how "exact" you want your calcs to be. I mean,
come on, do you actually weigh yourself before you do each and every
w&b calc?

On Thu, 02 Aug 2007 09:23:23 GMT, Tom L.
wrote:

You need to carry a lot of fuel for this difference to amount to
anything useful.

In the Cub, it would allow me to gain 2 pounds, or not to lose 2
pounds, as the case might be.

Every little bit helps!

Blue skies! -- Dan Ford

Claire Chennault and His American Volunteers, 1941-1942
from HarperCollins on August 21 www.flyingtigersbook.com

John Theune wrote:
Matt Whiting wrote:
Hilton wrote:
1. Go on a diet
2. Define a gallon of 100LL as weighing 5.82 lbs instead of the
usual 6 lbs - Mooney did it.

Is this legal/valid? If so, why don't all manufacturers do it?

Yes, diets are completely legal and valid and most of us should do so.

Mooney didn't "define" a gallon of 100LL to weight 5.82 lbs, that is
what it DOES weigh. Someone else "defined" it as 6 lbs many moons ago
to simplify calculations. If Mooney is doing as you say (I didn't
take time to verify), then they are just being more precisely correct,
if more impractical for their pilots.


Matt
For 50 gallons of fuel the difference is 9 pounds. Not much of a
difference as most peoples weight can change 4 pounds in a day based on
time of day and water in/out

I didn't say it made much of a difference, just that it is valid.

Matt

Hilton wrote:
Matt,

According to Wikipedia: "Avgas has a density of 6.02 lb/US gallon at 15 °C".
Not sure how 'correct' this is.

I've seen several different values, but most are less than 6.00 lbs/gal.

According to this site, the specific gravity of ConocoPhillips 100LL is 0.7.

http://www.conocophillips.co.uk/NR/r...D7/0/msds6.pdf



According to this site, the density of water at 15.5C is 8.33727 lbs/gal.

http://antoine.frostburg.edu/chem/se...r-density.html



Multiplying that by 0.7 yields: 5.836 lb/gal for the 100LL.

I can't vouch for the calculator site, but I trust the ConocoPhillips
MSDS much more than anything on Wikipedia, which is about the least
reliable source on the internet in my experience.

Matt

On Thu, 02 Aug 2007 17:08:46 -0400, Cubdriver usenet AT danford DOT
net wrote:


Every little bit helps!

That's why most FBOs have public bathrooms.

"All passengers must "evacuate" before boarding." G