Is there a reason why the RC-135 has vastly different engines than the KC-135?

Which version are you referring to?

I don't do engines but I know all KC-135s that I know of were rengined many years ago to a more efficent non-smokey design.  It's very possible that the RC-135s never got the upgraded engines.  (differnet aircraft so not funded/coverd by the contract)  Do they pour out black smoke during take-off?  I've never knowingly seen an RC-135 in 27 years of association with the Air Force.

Not my plane, can't help.

You must mean the EC-135s.   I think all the RCs have all been AMPd and re-engined.  Heck are there even any ECs left?

Ummm...because....


In 2005, the RC-135 fleet completed a series of significant airframe, navigational and power-plant upgrades which include re-engining from the Pratt & Whitney TF-33 to the CFM International CFM-56 (F-108) engines used on the KC-135R

If you're thinking of J(unk)Stars (E-8) they have small/shitty motors because supposedly the two inboard engines would interfere with the radar horizon of the underslung radar.  

OK so first of all, I got the planes mixed up. I didn't realize the RC-135 is not the same as the AWACS. Apparently the AWACS is the E-3. So the E-3 AWACS, and the KC-135 are what I am comparing, but the question still stands as they both use the -135 as the base aircraft, correct? I'm pretty sure Chairborne answered my question. I have seen the AWACS in person but won't say when or where for OPSEC reasons, afterall they post Security Forces on it for 24-hour guard so it must be a pretty important aircraft. The KC-135s on the other hand, a dime a dozen, I'm sick of them LOL.

The RJ's do have the big engines.

could be wrong being only a BUFF and former Herk Crew Chief, but I think the E-3s were built from scratch and save for a few of the early prototypes were not built off 135s

Just for clarification:





AWACS (E-3):











JSTARS (E-8)






RC-135:









KC-135:









What was your question exactly?

 

Most of the RC/EC fleet has been re-engined with CFM56/F108's like the 135R Model. This will be the third engine type for some .

J-Stars is getting P&W JT9's to replace the JT3/TF33 engines.

I think the two still serving  " Open Skies " WC-135's still have TF33's, Last of the E models that didn't get R model conversion are in the boneyard.

All I know is that I wanna go back on F-15C with 220's.

Not a fan of the TF33-P103 on the 52's.

you jets or crew chief up here?

I'd go back to 15's with -100s

There are zero ECs out there (in the boneyard).  Every single RC has F-108s.
The KC has essentially the same engines as the RC (Minor Differences).

The E-3 and the E-8 are true Boeing 707 airframes.  The KC/RC/OC/C(etc)-135s are not.  

        (wow, I just used "EXP's" face in a thread...   )


Keep in mind there are different variants of the RC-135s out there.

Oh, the Navy E-6B Mercury has been outfitted with the bigger engines.  KA3B is the resident expert on those as well.  KA3B, did the E-6 always have those engines, or did it start out with TF33s as well?

jets



never worked on the -100's, but I hear I aint missin much

That's only sorta true.  Many of the airframes were converted to KC-135R/Ts.  McConnell flies them, and they still have their UARSSI receptacles, so they are the only KC-135s that can be in-flight refueled.  When in place as a receiver they can also pass gas backwards through the boom to the tanker.  



 

So the JSTARS E-8 and the E-3 AWACS share the same engine? It looks like it from the pics. I am only asking about the AWACS as that is what I have been around, never seen an E-8 JSTARS but after seeing the pics I do remember seeing the RC-135 during Valiant Shield, or Cope North, don't remember which op. So the E-3 is NOT -135 based then? Because if the E-8 and E-3 are both 707 frames that explains why they both have the smaller engines and most of the -135 based aircraft do not.

One of the cool things (to some people) is the engines the USAF uses...

C-141A/B/C - TF33
B-52G/H - TF33
KC135- Used to have TF33
E3- TF33
E8- TF33

This allowed the Air Force to have common parts across their inventory for many decades... sure, there were some differences between the engines on the airframes but for the most part, they were almost interchangable.

I always thought it was cool the BUFF had the same engine as the C-141... they just used water injection... we didn't.

I was a sheet metal guy, this is outta my lane.

The background of the airframe doesn't really explain engine choice since as has been mentioned above the -135 series didn't start with CFM56 engines.  

You'll also note that some of the foreign E-3 AWACS have the CFM56 engines, having been built later in the program.

http://en.wikipedia.org/wiki/Boeing_E-3_Sentry

Exactly.   Although they are all part of the TF33 family, there are differences.

E-3 has the TF33-PW-100A, which produces 20,500 lbs of thrust
E-8 has the TF33-PW-102C, which produces 19,200 lbs of thrust

That's modern stuff.

Back in my day BUFFs and 135s burned water.


J-57s and water injection: Converting demineralized water into high decibel noice, producing the illusion of thrust.

The TF-33s on the BUFFs (H) used essentially the same core, but the fan duct set up was different.

It was the J-57s (used on A-model tankres and B-52s through the G) that had water injection.




Dang, I'm getting old...  

Only the "H" model BUFF used the TF33 engines.  The older G and D models used the J57 turbojet engine rather than turbofan.    The J57s did use water injection but I don't think the later "H' models ever used it though but I could be mistaken.

Oh the days of the J-57... lots of noise, little thrust... big planes...


TF33-P7A Bifurcated duct on the C-141B. I wish they would have put CFM56's on the Starlifter when I was flying on them... better fuel economy, greater thrust, quieter... but they didn't. They tested a few on #3 pylon but never converted the fleet...


Oh yeah, we only had 17,700 pounds of thrust... but we had 4 engines so it was sufficient... unless it was ungodly hot, high altitude, or we had a shit ton of cargo on board... then it wasn't enough.

thats what I was thinking too.  DEECs can kiss my ass, EECs always worked..... well most of the time.  Don't get me started on the POS 229s....

I didn't know that.

Of course, that wouldn't have helped the wing cracks.  

If you hated the DEEC's, you would have despised the Group 6 DEEC's even more.

It combined the DEEC and EDU as one unit, replacing the EDU with a crazy junction box. It was supposedly supposed to increase reliability by combining both units, but the junction box can kick out it's own fault codes, meaning it still needs to get changed like an EDU. Except when installed on F-16's they don't have the room that a 15 has, turning a 15 minute EDU job into 2+ hours.

It also replaced the AP3 borescope plug with a probe that had no function (as of when I PCS'ed in late 09). Which was a pain to remove when you had to scope a motor, and as always had it's own fault code you had to troubleshoot even though it was basically non-functioning.

What were they thinking?

I almost miss those days.

C-141B/C Crew Chief from 1987-2002
KC-135 Crew Chief 2002-2003

Now flying a desk and computer for another gov'mt agency. Less fun, more money.

HEY! We had the boron wing patch repairs...

Then we had the windshield post crack repairs...

Then C-17 funding was renewed and the 141's were mothballed.

You took my job! Wah, wah, wah!

Just kidding. The 141's were designed in the 50's, built in the 60's, SLEPPED and extended in the 70's, flown to hell in the 70's and 80's, and worn out in the 90's and still used into the 00's...

Shiiiiiiiiiiit, the E-3s are pretty much on that track.  Shifted slightly to the right (don't think they started designing it until the late 60s, with 71 being the first year model), but we're still flying the crap out of them today.   And I bet we'll be flying them in the 2020s.  

The 707 has been around a long time though.  

The taxpayers got their money's worth out of that airframe.

I was out in Tucson a couple years ago and passing by DM saw some being cut up.  

Thats the story I have heard also.  But I work on C-130's engines

Yeah, the airframes were paid off several times over... they were simply worn out. I  know most of the ones I flew on had close to or over 40,000 hours... and Lockheed said they were only designed originally to have 25,000 hours of flight time expectancy...

The CFM-56 is an incredible engine. It is the perfect demonstration of how even cancelled military aircraft programs can pay immense dividends. The dark secret about the CFM-56, perhaps the most successful jet engine of the past 30 years, is it was born of the B-1 bomber. The core of the engine is based on the General Electric F101 turbofan that was developed to power the B-1 (the GE F101 also served as the basis of the F110 that powered variants of the F-14 and F-16, and the F118 that powers the B-2 and U-2). The fan is a French design by SNECMA (BTW - The name "CFM International" comes from the prefix each company uses for its jet engine model numbers, GE uses "CF" (for its turbofans), SNECMA uses "M").



The complication was the F101 was classified when the CFM-56 was first conceived, and it was not considered wise to trust the French with the design of the US's most sophisticated jet engine. So, SNECMA was never provided with the details of the design of the F101's core, only details of  how the French-built fan section was to connect to it.



Of course, the B-1 would be revived later in its B-1B form by Ronald Reagan, but by then the CFM-56 was ready for commercial and military service.



United Airlines kickstarted production of the CFM-56 by choosing it to re-engine their DC-8s and give the airframe a second lease on life, then it would win the KC-135 re-engining program, before firmly establishing itself as the dominant turbofan of its size by being chosen by Boeing to power the 737-300 to 737-500 models (later versions of the CFM-56 would power the 737NG, A320 family, and variants of the A340).



None of the USAF's E-3s are equipped with the CFM-56 (F108). The British, French, and Saudi E-3s were all delivered new with CFM-56s, as were the Navy's E-6 TACAMO aircraft.



As for the J-STARS re-engining program, if it ever fully proceeds, the P&W JT8D will power these aircraft. As stated, the larger nacelles of the CFM-56 would actually mask portions of the J-STARS' keel-mounted canoe radar and limit its coverage. The JT8D-219 does have a smaller diameter fan and nacelle and would not present the same masking issues. Further, my understanding is the "plumbing" of the JT8D compared to the TF33 is similar enough to minimize some of the work that is otherwise required to re-engine 707 and C-135 airframes with the CFM-56.

I was with the 55th Strat Recon Wing back 1968 - 1971 out of Offutt AFB. But I can't tell you about the engines as I worked on the "black boxes that did the recon work" and I 'm not  going to tell you about them. Still don't know what has been declassified to this point.

All I know is they made a hell of a racket when taking off.

EBR666

Anyone who has worked the MD-80 series can attest to the fun that is involved in changing a fuel control or a starter on that engine.  Thankfully most everything else is easy to change on the engine.

The E-6B is also a "true" Boeing 707 airframe.

The E-6's were some of the last 707's to roll off the Boeing 707 production line.

The E-6's were the last 707's built for the US and the US Military.

The last 707 was an E-3D, built for the Royal Air Force.

Line Number / Construction Number / airframe / Type/Model/Series
(starting with the first Navy E-6 aircraft)
983      23430     707-E-6A TACAMO
984      23428     707-KE-3A Saudi E-3 converted to a tanker, powered by CFM56
985      23429     707-KE-3A Saudi E-3 converted to a tanker, powered by CFM56
986      23889     707-E-6A TACAMO
987      23890     707-E-6A TACAMO
988      23891     707-E-6A TACAMO
989      23892     707-E-6A TACAMO
990      23893     707-E-6A TACAMO
991      23894     707-E-6A TACAMO
992      24500     707-E-6A TACAMO
993      24109     707-E-3D RAF CFM56 AWACS
994      24501     707-E-6A TACAMO
995      24502     707-E-6A TACAMO
996      24110     707-E-3D RAF CFM56 AWACS
997      24504     707-E-6A TACAMO
998      24505     707-E-6A TACAMO
999      24506     707-E-6A TACAMO
1000     24115     707-E-3A Saudi CFM56 powered AWACS
1001     24503     707-YE-8B Prototype for new-build JSTARS with TF-33's, converted to E-3A CFM56 AWACS for Saudi Arabia
1002     24507     707-E-6A TACAMO
1003     24116     707-E-3A Saudi CFM56 powered AWACS
1004     24111     707-E-3D RAF CFM56 AWACS
1005     24508     707-E-6A TACAMO
1006     24117     707-E-3A Saudi CFM56 powered AWACS
1007     24112     707-E-3D RAF CFM56 AWACS
1008     24509     707-E-6A TACAMO
1009     24510     707-E-3A Saudi CFM56 powered AWACS
1010     24113     707-E-3D RAF CFM56 AWACS
1011     24114     707-E-3D RAF CFM56 AWACS
1012     24499     707-E-3D RAF CFM56 AWACS (last Boeing 707 built)

The E-6B was designed and built to be powered by the CFM56, the CFM-56-2A-2 with thrust reversers.

Not what I meant.

I mean I would love to go back to F-15s even with the POS -100 engines instead of the F119 powered thing I'm having to deal with now.

I liked DEECs!  But they were on -220s, never worked -229s.