KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Posted (4 years 6 months 2 weeks 2 days 2 hours ago) and read 12397 times:
The first flight for the re-engined E-8C J-STARS is scheduled for 17 Dec., from the NG facility in Melbourne, FL. NG is the prime contractor for this re-engine program. The new engine will be the JT-8D-219 engine, used on the commerical MD-88 airliner. The USAF will give this engine a military designation later. The test aircraft is E-8C T-3, which was originally the E-8B orignal J-STARS test aircraft. There were two E-8A test aircraft, also, later brought up to the E-8B and finally the E-8C configueration. The test engines, reversers and Seven-Q-Seven (SQS) pylons (called the propulsion pod system) were removed from the privately owned B-707-SQS aircraft, which already has completed FAA supplemential test certification.
Should these flight tests be a success, this may be an answer to the USAF tanker problem, as it would be easy for NG to up-grade the KC-135E aircraft with this SQS propulsion pod system.
KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Reply 2, posted (4 years 6 months 2 weeks 2 days ago) and read 12384 times:
Since military aircraft are generally exempt from noise restrictions, going with the JT8D-219s is consideraly cheaper than re-engining with the CFM-56-2B engines.
But, I agree the CFM-56s (USAF designation F-108) would make more sense as it is a more advanced engine, and already has full maintenance support within the USAF. The F-108 engines are on KC/RC-135s and C-40B/Cs, as well as USN E-6Bs and C-40A (the USAF provides depot level maintenance for both the E-6 airframe and the F-108 engines on them).
Spacepope From Vatican City, joined Dec 1999, 2744 posts, RR: 1 Reply 3, posted (4 years 6 months 2 weeks 1 day 19 hours ago) and read 12334 times:
The old story is that the CFM-56, since it has a much larger diameter than the TF-33s, actually blocks some of the sensor's line of sight. The JT8D-219 is very close to the original TF-33 external dimensions, so avoids those problems (and the subsequent long electronics retesting process).
Performance and efficiency will be improved regardless.
RayChuang From United States of America, joined Jun 2000, 7711 posts, RR: 5 Reply 4, posted (4 years 6 months 2 weeks 1 day 19 hours ago) and read 12329 times:
One reason why the USAF is looking at using a JT8D-219 variant is the large number of MD-80 planes now hitting retirement, which means a large number of surplus JT8D-219 engines will be available. They will find new life not only for the E-8 JSTARS, but possibly replace the TF33's on the E-3 AWACS fleet and re-engining the KC-135E fleet.
MD88Captain From United States of America, joined Nov 2001, 1292 posts, RR: 22 Reply 5, posted (4 years 6 months 2 weeks 1 day 19 hours ago) and read 12313 times:
21k per engine probably is plenty of trust. It is a better engine in a FOD rich environment. They are cheap, reliable, and plentiful. It will be really hard to scrap a pod on landing. No FADEC capability but then the E8 is a steam gauge type jet. It may be a sound choice given the mission.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 6, posted (4 years 6 months 2 weeks 1 day 18 hours ago) and read 12299 times:
Quoting Max Q (Reply 1): I must be missing something, why are they re-engining with the JT8D rather than the more powerful and efficient CFM56 ?
The 7q7 struts will bolt up to the existing 707-300 wing attachment the same as the jt3d struts saving tons in refurb costs , the CFM56 struts are a whole new fabrication and mod to the existing wing, the JT8D is a more reiable engine than the JT3d dog the E-8's have now, don't know if the E-3 will go to this the TF-33 P 100a is a powerful engine but it does problems of going places that don't like the noise it produces.
Does anybody know the cost per 7Q7 strut compared to the old 707/KC-135E strut which is over a 1mil a piece for a new replacement?
Gsosbee From United States of America, joined Jan 2005, 825 posts, RR: 0 Reply 7, posted (4 years 6 months 2 weeks 1 day 18 hours ago) and read 12296 times:
Spacepope is correct - the decision was an operational one. The CFM's interferred with the operational requirements of the airplane. (Of course they will not say what the problems are.)
All of the fit issues were resolved on the 135's, and the USAF would have preferred one engine type for spares and mx reasons.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 8, posted (4 years 6 months 2 weeks 1 day 18 hours ago) and read 12291 times:
Looking at the picture on the link provided the one thing that concerns me is keeping the oil in the Constand speed drive on the generator cool enough. I know it worked on the standard 707 but it is not running a high energy consuming surveilance radar on the belly along with a huge computer and communication suite plus does the E-8 fly at lower altitudes than a high flying E-3 which means less cooling going across its forced air fans and oil coolers.
Max Q From United States of America, joined May 2001, 3326 posts, RR: 19 Reply 9, posted (4 years 6 months 2 weeks 1 day 10 hours ago) and read 12190 times:
Very interesting, thanks for the information.
The best contribution to safety is a competent Pilot.
EBJ1248650 From United States of America, joined Jun 2005, 1932 posts, RR: 2 Reply 10, posted (4 years 6 months 2 weeks 1 day 9 hours ago) and read 12179 times:
Quoting MD88Captain (Reply 5): 21k per engine probably is plenty of trust. It is a better engine in a FOD rich environment. They are cheap, reliable, and plentiful. It will be really hard to scrap a pod on landing. No FADEC capability but then the E8 is a steam gauge type jet. It may be a sound choice given the mission.
How many years can these engines be supported via the logistics chain?
KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Reply 11, posted (4 years 6 months 2 weeks 1 day 4 hours ago) and read 12091 times:
Quoting Venus6971 (Reply 8): Looking at the picture on the link provided the one thing that concerns me is keeping the oil in the Constand speed drive on the generator cool enough. I know it worked on the standard 707 but it is not running a high energy consuming surveilance radar on the belly along with a huge computer and communication suite plus does the E-8 fly at lower altitudes than a high flying E-3 which means less cooling going across its forced air fans and oil coolers.
I would guess the CSD oil cooler is cooled with bleed air directly from the engine. I believe that is how the airlines keep the CSD cooled on the MD-80 series and B-737-200/ADVs.
Quoting EBJ1248650 (Reply 10): How many years can these engines be supported via the logistics chain?
The US military has a way of being able to support engines and equipment long after the production lines end. Just look at the B-52H and EA-6B engines, as well as the KC-135, C-130E/H, B-52H, and EA-6B airframes.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 12, posted (4 years 6 months 2 weeks 6 hours ago) and read 11938 times:
KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Reply 13, posted (4 years 6 months 2 weeks 3 hours ago) and read 11901 times:
According to the USAF, the current plans are to keep the E-8 J-STARS for another 50 years. But, all these B-707-320B/C airframes were bought used, including two CC-137s from the RCAF. I know they were completely refurbished when converted to the E-8 standards, but can they actually last that long? If thaey can last that long, then why can't the KC-135s last that long?
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 14, posted (4 years 6 months 1 week 6 days 19 hours ago) and read 11831 times:
Quoting KC135TopBoom (Reply 13): According to the USAF, the current plans are to keep the E-8 J-STARS for another 50 years. But, all these B-707-320B/C airframes were bought used, including two CC-137s from the RCAF. I know they were completely refurbished when converted to the E-8 standards, but can they actually last that long? If thaey can last that long, then why can't the KC-135s last that long?
If they do last that long I can gaurantee you that all the t6 aluminum on the fuselage will not be the original metal that came off the assembly line back in Renton and Boeing will be manufacturing wing spars again for the 707 which is usall suspect when a 707 is sent to her death.
LMP737 From , joined Dec 1969, posts, RR: Reply 15, posted (4 years 6 months 1 week 6 days 19 hours ago) and read 11833 times:
Quoting KC135TopBoom (Reply 11): I would guess the CSD oil cooler is cooled with bleed air directly from the engine. I believe that is how the airlines keep the CSD cooled on the MD-80 series and B-737-200/ADVs.
On the JT8D the CSD oil cooler is located in the fan bypass at about the six o'clock position. I've only had to change the cooler once, the CSD overheated. Typically it's the generator portion of the CSD/GEN that goes bad.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 16, posted (4 years 6 months 1 week 6 days 19 hours ago) and read 11832 times:
Quoting LMP737 (Reply 15): On the JT8D the CSD oil cooler is located in the fan bypass at about the six o'clock position. I've only had to change the cooler once, the CSD overheated. Typically it's the generator portion of the CSD/GEN that goes bad.
What is the usaul KVA rating for a standard JT8D installed generator, to put this perspective a E-3 has 8 generators 2 per engine at if I remember 65 KVA per generator to run a radar system that takes 114 volts 400HZ and steps it up to 20000 volts, don't know the power requrements of a E-8 but imagine it is close to a E-3. I can't imagine a standard Generator for a 727 or MD80 could handle that load.
LMP737 From , joined Dec 1969, posts, RR: Reply 17, posted (4 years 6 months 1 week 6 days 19 hours ago) and read 11820 times:
Quoting Venus6971 (Reply 16): What is the usaul KVA rating for a standard JT8D installed generator, to put this perspective a E-3 has 8 generators 2 per engine at if I remember 65 KVA per generator to run a radar system that takes 114 volts 400HZ and steps it up to 20000 volts, don't know the power requrements of a E-8 but imagine it is close to a E-3. I can't imagine a standard Generator for a 727 or MD80 could handle that load.
On the MD-80 the the CSD/GEN puts out 40kva. Of course the MD-80 does not have the power requirments of a JSTARS or AWACS.
KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Reply 18, posted (4 years 6 months 1 week 6 days ago) and read 11645 times:
Quoting LMP737 (Reply 15): Quoting KC135TopBoom (Reply 11):
I would guess the CSD oil cooler is cooled with bleed air directly from the engine. I believe that is how the airlines keep the CSD cooled on the MD-80 series and B-737-200/ADVs.
On the JT8D the CSD oil cooler is located in the fan bypass at about the six o'clock position. I've only had to change the cooler once, the CSD overheated. Typically it's the generator portion of the CSD/GEN that goes bad.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 19, posted (4 years 6 months 1 week 5 days 19 hours ago) and read 11594 times:
Quoting LMP737 (Reply 17): On the MD-80 the the CSD/GEN puts out 40kva. Of course the MD-80 does not have the power requirments of a JSTARS or AWACS
Maybe the MD -80 could load up the generators if ever decided to use the galleys and serve real food again
Ikramerica From United States of America, joined May 2005, 21041 posts, RR: 60 Reply 20, posted (4 years 6 months 1 week 5 days 18 hours ago) and read 11561 times:
Quoting KC135TopBoom (Reply 13): I know they were completely refurbished when converted to the E-8 standards, but can they actually last that long? If thaey can last that long, then why can't the KC-135s last that long?
While one side of the tanker argument was saying they needed to be replaced, there was also another side which said the current fleet could fly through 2040. So the answer isn't clear.
Of all the things to worry about... the Wookie has no pants.
Venus6971 From United States of America, joined Dec 2004, 1410 posts, RR: 1 Reply 21, posted (4 years 6 months 1 week 5 days 17 hours ago) and read 11555 times:
Quoting Ikramerica (Reply 20): While one side of the tanker argument was saying they needed to be replaced, there was also another side which said the current fleet could fly through 2040. So the answer isn't clear.
the current KC-135 fleet is very capable but what senior leadership fears one day they find some grounding problem that will condemn the acft and they go check the rest of the fleet and it exists on them also. That would no longer give us a global capability.
KC135TopBoom From United States of America, joined Jan 2005, 11738 posts, RR: 51 Reply 22, posted (4 years 6 months 1 week 4 days 1 hour ago) and read 11393 times:
Quoting Venus6971 (Reply 21): Quoting Ikramerica (Reply 20):
While one side of the tanker argument was saying they needed to be replaced, there was also another side which said the current fleet could fly through 2040. So the answer isn't clear.
the current KC-135 fleet is very capable but what senior leadership fears one day they find some grounding problem that will condemn the acft and they go check the rest of the fleet and it exists on them also. That would no longer give us a global capability.
While all that is true, it applies to B-52, E-8s, KC-135s, A-10s, C-5As, and C-130s, also.
TheSonntag From Germany, joined Jun 2005, 3350 posts, RR: 30 Reply 23, posted (4 years 6 months 1 week 1 day 22 hours ago) and read 11205 times:
Quoting KC135TopBoom (Reply 22): While all that is true, it applies to B-52, E-8s, KC-135s, A-10s, C-5As, and C-130s, also.
Which, all of them, have been used for many many years already...
The A400M project gets bashed from all sides because of its huge delays, but somehow I thing developing something entirely new after 50 years is not the worst idea. Certanly the current US planes do the job, but they all age, and I doubt that B-52s, E8s, JC135s, A10s, C5As and C-130s can all be replaced at the same time in 40 years from now...
Lumberton From United States of America, joined Jul 2005, 4708 posts, RR: 21 Reply 24, posted (4 years 6 months 1 week 1 day 22 hours ago) and read 11204 times:
Quoting TheSonntag (Reply 23): Certanly the current US planes do the job, but they all age, and I doubt that B-52s, E8s, JC135s, A10s, C5As and C-130s can all be replaced at the same time in 40 years from now...
Most likely they won't be replaced one-for-one. I would expect some missions to be taken over by UAVs.
"When all is said and done, more will be said than done".
25 747400sp: That's good! I love the way MD88 sounds at take off, so a plane with four instead of two of those great sounding JT8's is music to my ears.
26 KC135TopBoom: While that is a possibility, it is also possible a brand new airplane, like the KC-30 could also have such a problem. You like your music very loud,
27 Prebennorholm: Up front savings is surely an important factor, very likely also line of sight for sensors is also an issue, as stated in earlier posts. But there ma
28 SCAT15F: Correct me if I am wrong, but the JT8D-219 actually is just shy of 22,000 lb thrust, more than the TF-33 and the same as the CFM-56's fitted to the KC
29 747400sp: If it's the music of jet engines, YES Have a Marry Christmas and a Happy New Year.
30 KC135TopBoom: I like the music of the old J-57 (JT-3C) with water injection.
31 Spacepope: SHe flew last week! I've seen photos (not too terribly different), however has anyone found a video?
32 AWACSooner: Re-engining the E-3 eh? That'll happen when they finally get rid of my job on the jet...and that's been rumored for 20 years now. Frankly, this jet w
33 Venus6971: As soon as the E-3 gets the 40/45 mod which the french E-3 F's are going to get from Boeing.
35 TropicBird: Here is a picture of the re-engined aircraft taking off: http://www.airforce-magazine.com/DRA...29%202008/pix122908jointstars.aspx
36 KC135TopBoom: Isn't the USAF, NATO, and RAF E-3A/B/C/Ds being upgraded to the Block 50/55 configueration right now?
37 Spacepope: I love the looks of the TR buckets on that thing.
38 AWACSooner: You guys gotta understand how things work in Air Combat Command. The fighters get the top priority...followed by the bombers (obviously that'll change
39 KC135TopBoom: Now you know how it felt to be a KC-135 Tanker Toad in SAC. The bomber guys got everything, then came the SR guys and the RC guys, then the EC guys,
40 Venus6971: I sure did not feel that way when all your E-3's and RC-135's are broke all the attention you got trying just to get one flyable during OEF,OSW,or ON
41 AWACSooner: That's in the theater...back stateside, it's different.
42 Venus6971: As soon as we start going against somebody that has real Air Force threat or enforcing a no fly zone AWACS will become relevent again. Surprised they
43 AWACSooner: Heh... I wish. I'd take a Keflavik assignment in a heartbeat...but I'm still gunning for Elmo.
44 Lumberton: Gates restored the funding for the re-engining of the JSTARS. http://www.businessweek.com/news/201...orthrop-programs-in-2011-plan.html Compared to so
45 EBJ1248650: Something similar happened to the C-124 fleet in the early to middle 70's.
46 Zeke: The F-108 as on the KC-135 (CFM56-2) is not an advanced engine (it is basically not even as advanced as the CFM56-3 engine on the 737-300). It is vas
47 KC135TopBoom: While that is true today, the F-108 engine is a more advanced engine than the JT-8D-219 engine is, and much more advanced than the KC-135's original
48 Zeke: The JT-8D-219 was certified on February 22, 1985, the CFM56-2B June 25, 1982. Still seen nothing to say the entire fleet could go to 2030/2040, every
49 Spacepope: You still can't get around the physical size of the CFM powerplant, which is one of the main reasons why the JT8D-200 engine was chosen in the first p
50 Flighty: Granted you know a lot more than I do, but there are many KC-135 already sitting in the desert.... just not R models...
51 Zeke: The R model is different to even the E, it had numerous upgrades that are not on other KC-135s like an APU, new landing gear for the higher MTOW ( an
52 Venus6971: Those would be the the JT3d's they pulled off all the retired C-141's,C-135's that had been scraped retired or converted to the F108, there are no ne
53 KC135TopBoom: While that is true, the CFM-56 was a brand new engine design when certified in 1982, and the JT-8D-200 series was originally certified in 1978, and i
54 Spacepope: Question about that: The TF-33s that the C-141 used were a different mark than the ones currently used. Are they still used, after being rebuilt to a
55 Zeke: No, CFM applied for certification of the CFM-56-2 on August 7, 1975, FAA granted certification on November 8, 1979. The CFM-56-2B shares the same typ
56 A342: You can twist and turn it as you please, but the fact remains that ANY version of the CFM56 is more advanced than ANY version of the JT8D, including
57 MechatNEW: The CFM-56 cannot be used on the E-8, due to its large size which interferes with the large radar on the aircraft.
58 Venus6971: Actually the C-141 type TF-33 is close to the TF-33-P-100a on the E-3, both have 2 bleed valves to help with spoolup and spool down. the cores of the
59 Zeke: Do not disagree with you on the noise front, the JT8D still does not make enough as far as I was concerned. Please show me the TSFC values of all the
60 A342: http://www.jet-engine.net/civtfspec.html http://www.jet-engine.net/miltfspec.html You'll find: CFM56-2 series between 0.350 and 0.370 JT8D-200 series
61 Lumberton: This is a good, cost effective move. Are their better (and more expensive) options? Most likely. However, this admittedly "mature" engine is still a s
62 KC135TopBoom: Yes, the actual civilian engine designation for the USAF KC-135R and USN E-6B is the CFM-56-2B1 and the military designation for both the KC-135 and
63 Zeke: I do not trust those numbers, looking at the list the 737NG engine is less efficient than the early A320 CFM engines. The numbers you quoted are for
64 A342: True, but that doesn't change the fact that the JT8D is less efficient than the CFM56.
65 Spacepope: It also doesn't change the fact that you can't use the CFM on the E-8 without blinding its sensors, so it's a moot point.
66 A342: I don't buy that argument. Look at these pics: The radar is primarily looking downwards and sideways. The engines only interfere with the radar a lit
67 Venus6971: The mod to accept the new nacelle for the CFM and to modify the rudder system to compensate for yaw for the new engines is what is the major expense,
69 Spacepope: And the JT8Ds won't change it ANY amount. Why lose any sensor capability when losing none is an option? That is, after all, the only reason the E-8s
70 KC135TopBoom: The CFM-56 mod would be "bolt on" too. There are B-707 military varients with the CFM-56-2B engines (E-3, KE-3, E-6), as well as the KC-135. The E-8
71 Zeke: It also does not take into account the recent improvements on the JT8 front, some suggesting 6-8% which would make it better than the early CFM56 eng
72 Venus6971: The engine nacelle is a major mod, the CFM nacelle is not a bolt on, it is a major fabrication. Since the conversion from the J-57 each nacelle on ea
73 KC135TopBoom: I didn't know this 7Q7 engine mod includes the new thrust reverser mods AA is looking at for the JT-8D-2XX MD-83s. IIRC that mod promises a 6% to 12%
74 A342: Please elaborate, I have not heard of any such programme. 6-8% suggests major internal modifications which are unlikely to be widely retrofitted. As
75 Spacepope: I think the difference in the % savings can be attributed to different weights and stage lengths. I think that longer flights will yield higher numbe
76 A342: Maybe, but up to 12% is a bit much, don't you think? Lightsaber, our resident engine expert on a.net, is also quite sceptical. Just have a look at th
77 Ftrguy: The USN's E-6's do have the CFM-56-2A engines with 24000 lbs of thrust...
78 JoeCanuck: Here's the flight global article on the JT8 reverser upgrades; http://www.flightglobal.com/articles...t8d-thrust-reverser-to-market.html
79 KC135TopBoom: Has anyone heard or can confirm the EP-80 exhaust designed system will be added to the 7Q7 engine program on the E-8C? A 6%-12% fuel improvement would
80 Spacepope: Supposedly it uses the existing buckets, though modified. Weight change is minimal.
81 Lumberton: But price? I thought the whole point of the "exercise" was to use existing engines and save $$$?
82 Spacepope: What are you talking about? The existing buckets are used. There is an aerodynamic nose put over the now exposed leading edges of the buckets (don't
83 JoeCanuck: Here's a picture and another article about the mod; http://www.flightglobal.com/articles...-md-80-reverser-gets-american.html Here's a pdf with all th
84 KC135TopBoom: I'm not sure the EP-80 systems is designed for the 7Q7 nacelle, It is only seen on the MD-80 series necelles. Isn't the thrust revedrser buckets on th
85 Spacepope: From the photo posted in reply #35, the buckets are at the extreme aft end of both the MD-80 and 7Q7.
86 Spacepope: Update: new order... http://www.irconnect.com/noc/press/pages/news_releases.html?d=185599 MELBOURNE, Fla., March 2, 2010 (GLOBE NEWSWIRE) -- The U.S.
87 KC135TopBoom: This is good news for the E-8 aircraft, the reengining is finally beginning. This could also become a back-up plan to the KC-X program.
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