Big Mouth vs. Small Mouth

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KXY

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Unread post08 Jan 2008, 17:01

Ok, so I know the Vipers after block 25 had the more powerfull GE engines along with a larger intake.
My question is - Could someone post some reference pictures - comparing the "big mouths" with the "small mouths"?
Maybe I'm just blind, but I havn't been able to see a huge difference in the intake size. Also, I'd love to be able to recognize the different blocks when I see them, so any other obvious differences to help me decipher them would be much appreciated.
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ACMIguy

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Unread post08 Jan 2008, 17:08

KXY wrote:Ok, so I know the Vipers after block 25 had the more powerfull GE engines along with a larger intake.
My question is - Could someone post some reference pictures - comparing the "big mouths" with the "small mouths"?
Maybe I'm just blind, but I havn't been able to see a huge difference in the intake size. Also, I'd love to be able to recognize the different blocks when I see them, so any other obvious differences to help me decipher them would be much appreciated.


here you go
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KXY

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Unread post08 Jan 2008, 17:15

Ah. Thank you!
It looks as though the main difference is the inside..
I hope this wasn't too much of a noobish question. :oops:
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ACMIguy

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Unread post08 Jan 2008, 17:18

no problem

"The Modern Viper Guide" is a great book, you might want to pick up a copy.
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SixerViper

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Unread post08 Jan 2008, 17:54

ALL P&W-powered F-16s are "small mouths". ALL GE-powered F-16s after 86-0261 (block 30) are big-mouths. 86-0261 and previous GE jets are small-mouths.

Did you notice the slightly swept environmental intakes on the big-mouths and the non-swept ones on the small mouths? Well, the splitter between the top of the intake and the bottom of the fuselage is swept on big-mouths and not swept on small-mouths.

Other than the engine, which differentiates the 0s and the 5s/2s, the block 40/42s have a HUD with two combining glasses on them. Other C-models have HUDs with only one glass. There are other, extrememly esoteric differences between block 25s and 30/32s, but right now I don't have time to list them.
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AfterburnerDecalsScott

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Unread post08 Jan 2008, 19:10

Ah. Thank you!
It looks as though the main difference is the inside..
I hope this wasn't too much of a noobish question.


Well, no, the difference is in the shape of the intake opening, which is an external highly visible feature.
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KXY

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Unread post08 Jan 2008, 22:11

Now that I look at it more, it is more obvious. Thanks again. I'll have to get ahold of a copy of The Modern Viper Guide.
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Unread post09 Jan 2008, 03:57

KXY wrote:Ok, so I know the Vipers after block 25 had the more powerfull GE engines along with a larger intake..... Also, I'd love to be able to recognize the different blocks when I see them, so any other obvious differences to help me decipher them would be much appreciated.


The F100-PW-229 of the Block52 (and ANG Block42s) makes almost the same power as the F110-GE-129 of the Block50, but still retains the small mouth intake.

The intake size isn't needed for the power it's needed for the airflow requirements of the engine. The GE engine moves more air per second than the PW. The PW may use less air but has a higher temperature and exhaust velocity.

The exhaust nozzles are an easy way to tell which engine is installed. A longer more straight nozzle is on the PW F100, while the GE F110 has a shorter more curved nozzle.

Also; If you can hear the jet fly over, the PW will make a "zipping" noise when the throttle is moved. (The PW uses an air-motor to power the nozzle actuators which are mechanical) The GE nozzle is hydraulic and does not make noise when it's position is changed.
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JakeMelampy

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Unread post09 Jan 2008, 04:22

ACMIguy wrote:no problem

"The Modern Viper Guide" is a great book,


Thanks! I had a ton of help putting it together.

Jake
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Raptor_One

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Unread post09 Jan 2008, 09:51

That_Engine_Guy wrote:
KXY wrote:Ok, so I know the Vipers after block 25 had the more powerfull GE engines along with a larger intake..... Also, I'd love to be able to recognize the different blocks when I see them, so any other obvious differences to help me decipher them would be much appreciated.


The F100-PW-229 of the Block52 (and ANG Block42s) makes almost the same power as the F110-GE-129 of the Block50, but still retains the small mouth intake.

The intake size isn't needed for the power it's needed for the airflow requirements of the engine. The GE engine moves more air per second than the PW. The PW may use less air but has a higher temperature and exhaust velocity.

The exhaust nozzles are an easy way to tell which engine is installed. A longer more straight nozzle is on the PW F100, while the GE F110 has a shorter more curved nozzle.

Also; If you can hear the jet fly over, the PW will make a "zipping" noise when the throttle is moved. (The PW uses an air-motor to power the nozzle actuators which are mechanical) The GE nozzle is hydraulic and does not make noise when it's position is changed.


I realize you're going to shoot back with a retort to this, but I feel the need to inject some actual facts now that you've brought your obviously biased pro-P&W spin into this thread.

1) The intake size is needed for the "power". The earliest block 30s to get the F110-GE-100 did not have the big inlet. Because they still used the small inlet, they produced less thrust in certain portions of the envelope BECAUSE the inlet capture area was not sufficient to provide the engine with peak airflow. Saying that the larger intake is only needed for the *installed* engine's airflow requirements and not to produce more thrust is like saying the F-15's variable geometry intakes are only to reduce stagnation pressure recovery losses at high Mach and not to produce more thrust. In both cases, the intakes improve one aspect of the airflow to the engine which directly affect the installed thrust output of both aircraft throughout the flight envelope.

2) When the F110-GE-100 came online, the F100-PW-229 was not operational. You had the Block 30 with F110-GE-100 and the Block 32 with the F100-PW-220. Then you had the Block 40 and 42 variants with the same respective engines. Not until the Block 50 and 52 variants came along did you have the Block 52 flying with the F100-PW-229 which is slightly superior to the F110-GE-100. Of course the Block 50s were flying with the F110-GE-129 which give that variant superior flight performance with respect to the Block 52/F100-PW-229 throughout the ENTIRE flight envelope. The F110-GE-129 has the better engine thrust to weight ratio and the Block 50 F-16C has the better aircraft thrust to weight ratio as well. The Block 50 is a superior aircraft in terms of raw flight performance. Why? Because it has better installed thrust... period. That's THE only reason. The two aircraft are virtually the same with the exception of the different inlets.

3) Comparing only the Block 52/F100-PW-229 (only recently installed in ANG Block 42s by the way) to the Block 50/F110-GE-129 is disingenuous. Why? Because you're leaving out the fact that all Block 30s and 40s with F110-GE-100s outperformed their Block 32 and 42 siblings that continued to use the F100-PW-220. Even the small mouth block 30s outperformed the Block 32s. And if you want to talk about Block 42s flying with F100-PW-229s, you might as well state that if you threw F110-GE-129s in Block 40s, they'd be equally superior in raw flight performance as the Block 50s are to the 52s. As for the GE F110 engine series requiring a larger inlet to produce more power (WAY more for the -100 vs. PW-220 and significantly more for the -129 vs. PW-229) due to their increased airflow requirements, that's not surprising seeing as how the F-16 was designed specifically to fly with P&W's F100 series AB turbofan.

To sum things up, the facts are that ALL F-16s with F110-GE-100s have vastly superior flight performance when compared to F-16s flying with F100-PW-220s. All F-16s with F110-GE-129s have significantly better flight performance when compared to F-16s flying with the F100-PW-229. You always have to match the intake to the engine for optimal performance. If the bigger inlet didn't give the F-16s flying with GE F110s significantly better flight performance, then you might have a case for speaking out against the two. The introduction of the F100-PW-229 narrowed the performance gap between PW F100 series and GE F110 series engines, but it did NOT close it by any means. The F110-GE-129-powered F-16s still perform better than their F100-PW-229-powered siblings. Why you can't simply accept this and move on is beyond me. You are misinforming people here however, and there's no good reason I can think of for you to do that. It doesn't change the facts of the matter which I have just stated clearly and correctly.

And for the record, I think P&W produce amazing engines and are pioneers in their field... especially when it comes to to modern fighter engines. The F100, F119, and F135 either were or currently are vast improvements over anything else the competition has to offer. GE has been successful at catching up and in some cases overtaking its rival P&W, however. Big deal... who cares? You're still caught up in "The Great Engine War" which is no longer being fought. In case you hadn't noticed, the fastest, most lethal fighter in the world has only one company providing its thrust... P&W. GE's proposed powerplant for use in the F-35 has yet to be realized. They're not even in the ballgame yet. The facts are clear when it comes to the GE F110 vs. PW F100 though... and I just stated them. Feel free to try and contradict me, but I am VERY confident in my statements and you would be hard pressed to find ANYONE of authority to dispute what I've just written. If for some reason you did, they'd no doubt favor P&W like you for whatever reason. I think they call that brand loyalty, don't they?
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ACMIguy

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Unread post09 Jan 2008, 14:08

JakeMelampy wrote:
ACMIguy wrote:no problem

"The Modern Viper Guide" is a great book,


Thanks! I had a ton of help putting it together.

Jake


You are very welcome, any chance I can get a signed copy?
Great work hope to see more soon! :D
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tjodalv43

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Unread post09 Jan 2008, 16:09

Hey Jake, just orded a book! Looking forward to it!

Here's a nice picture I found of the intakes side by side.
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JetTest

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Unread post09 Jan 2008, 17:10

I think Raptor One is exagerating the difference in thrust a bit. GE's own numbers are 29000 max thrust at 3980 lbs weight for the -129. PW claims 29160 max at 3740 weight, so the difference seems pretty small based on that. This brings a question to my mind. Why have virtually all new F16 contracts since UAE been sold and delivered with PW power?
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Unread post09 Jan 2008, 17:45

JetTest wrote: ...Why have virtually all new F16 contracts since UAE been sold and delivered with PW power?...

Beacuse Pratt & Whittney have a better International Sales team....

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JetTest

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Unread post09 Jan 2008, 18:00

To me that would not explain why customers such as Greece and Isreal, that already have both types, have selected PW for follow-on buys with no engine competition. In those cases there was virtually no marketing involved, but a summary award by the customer. I think those decisions were made on the complete package of cost, performace, and supportability.
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