Settle the Bet

[Typhoon1244]

I think he said turbo fan.

Uh, the JT8D is a turbofan.

 

[DCitrus9]

jt8d is considered a jurboJET. The fan does not produce any appreciable thrust (5%?) compared to a turbofan. With the BR715 EPR is the primary control for the fadec, N1 is the reversion when sans computer.

 

[TrafficInSight]

jt8d is considered a jurboJET. The fan does not produce any appreciable thrust (5%?) compared to a turbofan. With the BR715 EPR is the primary control for the fadec, N1 is the reversion when sans computer.

Hmm... I don't think I've ever seen it called anything but a low bypass turbofan...

can you provide some sources?

 

[furloughfodder]

How 'bout the JT9D Pratt & Whitney dual-spool \ axial flow \ high bypass Turbofan?

Fan produces 75% of the 52,000 lbs of thrust with a 5 to 1 bypass ratio.

...at least that's what somebody told me

 

[TrafficInSight]

How 'bout the JT9D Pratt & Whitney dual-spool \ axial flow \ high bypass Turbofan?

Fan produces 75% of the 52,000 lbs of thrust with a 5 to 1 bypass ratio.

...at least that's what somebody told me

That's fine for a JT9D but we're talking about JT8D's

 

[Torqued]

The JT8-D is a turbofan, but has a low bypass ratio of about 1.7 to 1. Never heard of it called a turbojet.

 

[dash8driver]

some people like their cucumbers pickled...

 

[Typhoon1244]

jt8d is considered a jurboJET.

By who? You?

The fan does not produce any appreciable thrust (5%?) compared to a turbofan.

The JT8D is a turbofan. The 1.7-to-1 ratio Torqued mentioned is about right.

Now if it had no fan at all, then you could consider it a jurbojet.

(You have actually flown the '9...right?)

 

[FlyFlyFly]

OK, this is a neat discussion, let me try my question again:

Are there any turboFAN (I did say FAN and not JET) engines out there where the primary measure of power is EPR, other than the CF700?

I conclude that the JT8 is arguably a turbofan, so it would qualify, therefore do you set power on it primarily by EPR? I assume the JT8 is that ultra low bypass affair of a stovepipe slung under the wings of 737-100 & 200s.

It also appears that the BR715 has a FADEC that uses EPR to set power, so I would assume the BR710s on a GV would have the same.

Any others?

 

[DCitrus9]

Doh!

Disregard, I was coming in broken and stupid!

Due to the late hour and several coors lights, my post is factually innaccurate regarding turbojet. I've been off of the 9 for a few years, and am simply too lazy to look it up.