C-5 Tidbits (Of Information) 4 of 4

[Zomby Woof]

[octothorpe]

"Zomby Woof" > wrote in message
news:0sULi.28297$x%6.23120@pd7urf2no...
>
>
>

42 Tons of air per minute. At that rate it could stay aloft for ~15
minutes. That's assuming a 14.7 to 1 air to fuel ratio.

--
Tom

[adelsonsl]

pretty cool dude!!1
"octothorpe" > wrote in message
news:yQULi.12282$Ww5.888@trnddc03...
>
> "Zomby Woof" > wrote in message
> news:0sULi.28297$x%6.23120@pd7urf2no...
>>
>>
>>
>
> 42 Tons of air per minute. At that rate it could stay aloft for ~15
> minutes. That's assuming a 14.7 to 1 air to fuel ratio.
>
> --
> Tom
>

[Rolf T. Kappe]

On Sun, 30 Sep 2007 21:48:14 GMT, "octothorpe"
> wrote:

>
>"Zomby Woof" > wrote in message
>news:0sULi.28297$x%6.23120@pd7urf2no...
>>
>>
>>
>
> 42 Tons of air per minute. At that rate it could stay aloft for ~15
>minutes. That's assuming a 14.7 to 1 air to fuel ratio.
All of which shows that a TF-39 engine has a lot higher air to fuel
ratio. There is no particular reason for a jet engine to fully
combust the oxygen in the air, which is where that 14.7 figure comes
from. Secondly, the TF-39 has a bypass ratio of 8 to 1, meaning 8
times as much air goes around the hot section as through it, and never
gets combusted at all.
Try
http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.html
(especially the CF6 model)
If you play with this, you can see a jet engine at full power could
could have a air fuel ratio of 60. With the 8:1 bypass ratio, the
overall number could be 540. This would give an answer of about nine
hours at full power.

--Rolf

[octothorpe]

"Rolf T. Kappe" > wrote in message
...
> On Sun, 30 Sep 2007 21:48:14 GMT, "octothorpe"
> > wrote:
>
>>
>>"Zomby Woof" > wrote in message
>>news:0sULi.28297$x%6.23120@pd7urf2no...
>>>
>>>
>>>
>>
>> 42 Tons of air per minute. At that rate it could stay aloft for ~15
>>minutes. That's assuming a 14.7 to 1 air to fuel ratio.

> All of which shows that a TF-39 engine has a lot higher air to fuel
> ratio. There is no particular reason for a jet engine to fully
> combust the oxygen in the air, which is where that 14.7 figure comes
> from. Secondly, the TF-39 has a bypass ratio of 8 to 1, meaning 8
> times as much air goes around the hot section as through it, and never
> gets combusted at all.
> Try
> http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.html
> (especially the CF6 model)
> If you play with this, you can see a jet engine at full power could
> could have a air fuel ratio of 60. With the 8:1 bypass ratio, the
> overall number could be 540. This would give an answer of about nine
> hours at full power.
>
> --Rolf

I suspected there would be a problem with the calculation. I completely
forgot about "bypass".
Thank you for the informed answer and the URL. That looks especially
interesting.

--
Tom