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Why The Usaf Cancel The YC-14 & YC-15  
User currently offline747400sp From United States of America, joined Aug 2003, 3757 posts, RR: 2
Posted (8 years 10 months 2 days 2 hours ago) and read 11682 times:

In the mid 70's the USAF was looking for a jet replacement for the C-130. Both Boeing and Mcdonnell Douglas flew their prototype, Boeing had the YC-14 and Mcdonnell Douglas YC-15. The YC-14 and YC-15 out performed the USAF expectation. So why the USAF drop the project.


PS I thought the YC-15 was the best choice

25 replies: All unread, showing first 25:
 
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 1, posted (8 years 10 months 2 days 1 hour ago) and read 11656 times:

Because the C-130 could do everything the YC-14 and YC-15 clould do, and do it for a lot less money.

User currently offlineDougloid From , joined Dec 1969, posts, RR:
Reply 2, posted (8 years 10 months 2 days 1 hour ago) and read 11654 times:

Good point. The money wasn't totally wasted though, a lot of the YC15 development work went into the C17

User currently offlineN328KF From United States of America, joined May 2004, 6491 posts, RR: 3
Reply 3, posted (8 years 10 months 2 days ago) and read 11641 times:

Quoting Dougloid (Reply 2):
Good point. The money wasn't totally wasted though, a lot of the YC15 development work went into the C17

A lot? The C-17 looks like a super-sized, swept-wing YC-15.  Wink



When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineScbriml From United Kingdom, joined Jul 2003, 12868 posts, RR: 46
Reply 4, posted (8 years 10 months 7 hours ago) and read 11463 times:
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The YC-15 looked cool, but those engines didn't look like they could get it off the ground.

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User currently offlineDougloid From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 10 months ago) and read 11397 times:

Quoting N328KF (Reply 3):
Quoting Dougloid (Reply 2):
Good point. The money wasn't totally wasted though, a lot of the YC15 development work went into the C17

A lot? The C-17 looks like a super-sized, swept-wing YC-15.

And even before the C17 got built we were all proud that the YC15 whupped the Boeing offering.  bigthumbsup   bigthumbsup 


User currently offlineWhiteHatter From , joined Dec 1969, posts, RR:
Reply 6, posted (8 years 9 months 4 weeks 1 day 1 hour ago) and read 11278 times:

Quoting Scbriml (Reply 4):
The YC-15 looked cool, but those engines didn't look like they could get it off the ground.

Deceptive photos.

The YC-15 used the JT8D, so it had the power of two 732 or DC-9 aircraft after all.

Boeing's offering used a pair of CF6 engines.


User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12178 posts, RR: 51
Reply 7, posted (8 years 9 months 3 weeks 3 days 22 hours ago) and read 11140 times:

The Boeing YC-14 was technologily musch more advanced. The 2 CF-6 engines were mounted on the wing leading edge, thrust was blown over both the upper and lower wing surface, producing an enormaos amount of lift. The YC-14 clearly out performed the 4 engine MD YC-15. It could lift a lot more weight than either the C-130 or YC-15.

But, later in life, the YC-15 test airplane was used to flight test the (then newly designed) CFM-56-B2 engine.


User currently offlineN328KF From United States of America, joined May 2004, 6491 posts, RR: 3
Reply 8, posted (8 years 9 months 3 weeks 3 days 11 hours ago) and read 11110 times:

Quoting KC135TopBoom (Reply 7):
The Boeing YC-14 was technologily musch more advanced. The 2 CF-6 engines were mounted on the wing leading edge, thrust was blown over both the upper and lower wing surface, producing an enormaos amount of lift. The YC-14 clearly out performed the 4 engine MD YC-15. It could lift a lot more weight than either the C-130 or YC-15.

Yes, and then the Soviets wound up using the Coanda effect for the An-72 design.



When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineRayChuang From United States of America, joined Jun 2000, 8034 posts, RR: 5
Reply 9, posted (8 years 9 months 3 weeks 2 days 4 hours ago) and read 11045 times:

Quoting 474218 (Reply 1):
Because the C-130 could do everything the YC-14 and YC-15 clould do, and do it for a lot less money.

That and the fact the USAF realized they truly needed a bigger plane than the YC-14/YC-15, so as not to repeat the experience with the C-141 Starlifter. The result is the C-17A Globemaster III.


User currently offlineZwaving From Canada, joined Nov 2006, 21 posts, RR: 0
Reply 10, posted (7 years 5 months 1 day 13 hours ago) and read 10307 times:
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What was the experience factor with the starlifter?


There is no free lunch!
User currently offlineStealthZ From Australia, joined Feb 2005, 5743 posts, RR: 44
Reply 11, posted (7 years 5 months 1 day 13 hours ago) and read 10305 times:
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Quoting Zwaving (Reply 10):
What was the experience factor with the starlifter?

IIRC, it was too small for it's weight carrying capacity.
If that doesn't seem to make sense, it often filled the available volume before reaching max weight. This led to the C-141B which were C-141A with plugs inserted in the fuselage fore and aft of the wings adding a total of 23ft 4in to the length.

Cheers



If your camera sends text messages, that could explain why your photos are rubbish!
User currently offlineDL021 From United States of America, joined May 2004, 11447 posts, RR: 75
Reply 12, posted (7 years 5 months 1 day 13 hours ago) and read 10301 times:

Quoting StealthZ (Reply 11):
IIRC, it was too small for it's weight carrying capacity.
If that doesn't seem to make sense, it often filled the available volume before reaching max weight. This led to the C-141B which were C-141A with plugs inserted in the fuselage fore and aft of the wings adding a total of 23ft 4in to the length.

I think that it's a very rare thing to max out a freighter weight wise prior to filling the volume. What they really wanted was a wider airplane to make more stuff fit inside.



Is my Pan Am ticket to the moon still good?
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12178 posts, RR: 51
Reply 13, posted (7 years 5 months 1 day 13 hours ago) and read 10298 times:

The C-141B mod also added air refueling capability that the C-141A did not have.

User currently offlineStealthZ From Australia, joined Feb 2005, 5743 posts, RR: 44
Reply 14, posted (7 years 5 months 1 day 13 hours ago) and read 10298 times:
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Quoting DL021 (Reply 12):
I think that it's a very rare thing to max out a freighter weight wise prior to filling the volume.

Not rare at all, much cargo is not that dense.
Much military cargo comprises things like helicopters, wheeled vehicles etc these will max out volume long before weight is an issue.

Quoting DL021 (Reply 12):
What they really wanted was a wider airplane to make more stuff fit inside.

Absolutely agree, but what you want you can't always have.. had to wait for the C-17 to get the width.
Adding width to the C-141 was not an option so a stretch was the compromise they had to live with.

Quoting KC135TopBoom (Reply 13):
The C-141B mod also added air refueling capability that the C-141A did not have.

Sorry KC135... should have mentioned that!


Cheers

[Edited 2007-07-21 15:00:19]


If your camera sends text messages, that could explain why your photos are rubbish!
User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 15, posted (7 years 5 months 1 day 7 hours ago) and read 10226 times:

Quoting 474218 (Reply 1):
Because the C-130 could do everything the YC-14 and YC-15 clould do, and do it for a lot less money.

......and 30 years later it is still doing it.



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineCTR From United States of America, joined Jul 2005, 303 posts, RR: 0
Reply 16, posted (7 years 5 months 1 day 7 hours ago) and read 10215 times:

Neither the YC-14 or YC-15 programs were canceled. To be canceled you first need to be awarded a contract to develop a production aircraft.

Both the YC-14 and YC-15 were technology development prototype aircraft built to test advanced heavy lift concepts. The size of these aircrafts was based on the minimum size (least $$$) required to be scaleable to larger aircraft, not as a C-130 replacement.

Each aircraft had their own merits. Although the lift performance of the YC-14 was impressive, the associated complexity in the engine, wing and moving surfaces was judged by the USAF as unacceptable.

Have fun,

CTR



Aircraft design is just one big compromise,,,
User currently offlineAirSpare From United States of America, joined Jun 2006, 589 posts, RR: 6
Reply 17, posted (7 years 5 months 1 day 6 hours ago) and read 10207 times:

Quoting KC135TopBoom (Reply 13):
The C-141B mod also added air refueling capability

To chime in a 4th time, it also had major wing root mods, IIRC, didn't it have problems with cracks?



Get someone else for your hero worship fetish
User currently offlineL-188 From United States of America, joined Jul 1999, 29832 posts, RR: 58
Reply 18, posted (7 years 5 months 1 day 6 hours ago) and read 10193 times:

Quoting Zwaving (Reply 10):
What was the experience factor with the starlifter?



Quoting StealthZ (Reply 11):
If that doesn't seem to make sense, it often filled the available volume before reaching max weight. This led to the C-141B which were C-141A with plugs inserted in the fuselage fore and aft of the wings adding a total of 23ft 4in to the length.

A little history here, the C-141 was built to replace the C-133. Both of which had one mission in life when they where developed. To carry a minuteman missle in it's shipping container. That is why they where able to keep the C-130 sized floor dimensions.

But as noted it was quickly realized that a lot of their capacity was wasted when they wheren't carrying a heavy ICBM and it's shippng cradle so that is why they decided to stretch the aircraft and take advantage of the whole lift capability of the aircraft.

Quoting CTR (Reply 16):
Both the YC-14 and YC-15 were technology development prototype aircraft built to test advanced heavy lift concepts. The size of these aircrafts was based on the minimum size (least $$$) required to be scaleable to larger aircraft, not as a C-130 replacement.

That was my understanding, it was a test program not a program leading to a production run.



OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
User currently offlineThorny From , joined Dec 1969, posts, RR:
Reply 19, posted (7 years 5 months 1 day 5 hours ago) and read 10169 times:

Quoting AirSpare (Reply 17):
To chime in a 4th time, it also had major wing root mods, IIRC, didn't it have problems with cracks?

No, that was the C-5A.


User currently offlineAirSpare From United States of America, joined Jun 2006, 589 posts, RR: 6
Reply 20, posted (7 years 5 months 1 day 3 hours ago) and read 10146 times:

Quoting Thorny (Reply 19):
C-5A.

I thought there was a cracking problem. Here is a good synopsis. I had remembered it as part of the upgrade to the B models but it wasn't.



Get someone else for your hero worship fetish
User currently offlineTropicBird From United States of America, joined May 2005, 502 posts, RR: 0
Reply 21, posted (7 years 5 months 1 day ago) and read 10102 times:

As I recall the YC-15 was the precursor to the C-17... MDC won the competition over Boeing.

User currently offlineMCIGuy From United States of America, joined Mar 2006, 1936 posts, RR: 0
Reply 22, posted (7 years 4 months 4 weeks 1 day 20 hours ago) and read 9939 times:

Quoting TropicBird (Reply 21):
As I recall the YC-15 was the precursor to the C-17... MDC won the competition over Boeing.

I was gonna say, put some HBT engines on that YC-15 and you have the look of the C-17, even if the 17 is larger.  

PS> I had the pleasure of seeing the YC-14 at Pima. There's just something about touching one of only two aircraft.  

[Edited 2007-07-23 07:44:56]


Airliners.net Moderator Team
User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 23, posted (7 years 4 months 4 weeks 1 day 13 hours ago) and read 9862 times:

Quoting StealthZ (Reply 11):
If that doesn't seem to make sense, it often filled the available volume before reaching max weight. This led to the C-141B which were C-141A with plugs inserted in the fuselage fore and aft of the wings adding a total of 23ft 4in to the length.

That was the problem, being just a stretched C-130 really. It was that...then the C-5. No middle ground like the C-17 is now.

I did like the old 141 though....miss those old Lockheeds.

DeltaGuy


User currently offlineAeroWeanie From United States of America, joined Dec 2004, 1610 posts, RR: 52
Reply 24, posted (7 years 4 months 4 weeks 9 hours ago) and read 9703 times:
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Quoting AirSpare (Reply 17):
To chime in a 4th time, it also had major wing root mods, IIRC

The first aircraft modified got the wing root mods, but they weren't incorporated on subsequent aircraft, to save money.


User currently offlineThorny From , joined Dec 1969, posts, RR:
Reply 25, posted (7 years 4 months 4 weeks 2 hours ago) and read 9663 times:

Quoting TropicBird (Reply 21):
As I recall the YC-15 was the precursor to the C-17... MDC won the competition over Boeing.

Sort of. Changing requirements favored an outgrowth of the YC-15 over the YC-14, but the YC-14 was the better aircraft in meeting the original requirements.

The Air Force belatedly decided it wanted a much larger airlifter than the C-130-sized STOL prototypes it got in the YC-14 and YC-15. Boeing's YC-14 ran rings around the YC-15 in most areas: STOL in particular (and the YC-14 needed only half the runway of a C-130 for the same payload, so it isn't true C-130 could do everything YC-14 could.) Remember YC-14 and YC-15 were developed in a STOL tactical airlift competition to succeed C-130, not a competition to succeed C-141 (which C-17 eventually won.)

But when the Air Force decided it wanted a new strategic airlifter and not a tactical airlifter (probably as headaches with the hangar queen C-5 grew), the STOL capability wasn't as important, and the YC-15 was more easily scaled up to what the Air Force now wanted. So YC-14 ended up as an impressive curiosity and YC-15 led to C-17.


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