Improving the C-123 Provider

[NVSMITH]

-This is way post WW2 but the aircraft was conceived during the war... as a glider. The C-123 Provider had a long, varied and quite successful career filling many quite disparate missions. I'm not a big Wiki fan but he Wiki page on the C-123 is worth a glance if only to look at the variants.
-In the US we don't really like to upgrade weapons systems. After all, the money comes from designing, testing and building the latest beastie with brand new, sometimes theoretical, bells and whistles instead of steadily improving something that we know works. Look at the histories of the A-10 vs. the F-35.
-There are two C-123 variants listed on the Wiki page that I think really should have been considered: the C-123L and the C-123T; both replaced the recip engines with turboprops. The 123L called for GE T-64 engines; I don't know what was proposed for the 123T. My thinking is that the Providers should have been overhauled and fitted with the same family of engine that powered the C-130 Hercules for commonality of maintenance and operation.
-Would this have been like the Basler BT-67 DC-3 conversion that ended up stretching the fuselage something over a meter and increasing cargo volume? I don't know. Certainly changing from R-2800 Double Wasps to whatever 3500+ hp turboprop, in itself a lighter engine, would have increased cargo capacity, speed and probably range and the two turbojet extra engines with special fuel systems and maintenance requirements would go away.
-Why bother? The Army used C-7 Caribous for a while until the Air Force complained and took most of them away. Some Army National Guard (NOT Air National Guard) units kept them: I flew in both California and Puerto Rico NG Caribous in the early '80s. The Army also tried out a few C-8 Buffalos; I saw a couple that belonged to the 11th Air Assault Division (Test) in Vietnam. In the late '80s both the Army and the Air Force realized that an aircraft smaller than the Hercules was needed for tactical airlift support in "austere" environments and experimented with a bunch of small, usually semi-STOL, twin engine cargo birds. The C-27A Spartan, which served from about 1990 to about 1999, had the GE T-64 engines posited for the C-123L. The C-27J, oddly enough, uses engines and internal systems compatable with/derived from C-130s, was standardized in 2007 and the Air Force dumped them in 2012. CASA C-41s, C-23 Sherpas and other SOCOM special purchase, or rental, have been in the inventory.
-Result: we still don't have an in theater fixed wing transport.
-Would it work? Look at the turboprop versions of the DC-3 and look at what the Japanese did to the P-2 Neptune to make the P-2J.

 

[cvairwerks]

The Thai mod program was being done in Waco, Texas, where I went to tech school in 1979/81. It was a fairly extensive mod program with not only an engine change, but the addition of an APU, boosted controls and converting to a wet wing. There was also extensive rewiring of the aircraft as well as adding a deice system. I think the Thai's ran out of money to fund the mod well before the 1st aircraft was finished. I don't remember the mod aircraft even running the engines when I was there.

 

[FLYBOYJ]

A few dynamics here -

I briefly worked around a C-123, you could put rocket engines on it and it's not going to out perform a C-130 except for getting into smaller airfields. The interior was a bit archaic, IIRC with the elevated flight station, the flight engineer sat on this seat that was hinged on the cockpit entry door and swung into position. I knew people who flew them as well as C-130s and the C-123 was not loved, especially the older Vietnam deployed units that made it into National Guard. However, for the era it was built and deployed, it was a good workhorse that supplemented early C-130 models.

The Caribous and Buffalo were great aircraft, but their time within in the Army was affected by top brass wrestling away mission requirements from each other. The Johnson-McConnel agreement is what took the fixed wing mission away from the US Army. Also consider that those in each branch of the US Military responsible for the planning and procurement of new equipment are usually limited in their assignments and those "think tank wiz kids" jump at the flavor of the moment. If they are reassigned, PCS or retire, a new group comes in and may set the envisioned mission and procurement requirement in a total different direction. I think about 150 Caribous were used by the US Army during Vietnam, just a handful of Buffaloes were operated by the US Army and USAF. I think all of these aircraft eventually wound up with the USAF who eventually retired them during the post Vietnam war period.

Another dynamic is something called "small fleet dynamics" in which the operator has to justify the operation of a small fleet as it perceived that operational costs will not justify the operation of such aircraft on a normal basis. As mentioned, I think there were only a "few" C-7s and C-8s being operated into the 1980s.

25 years plus working around some of these programs as a contractor, I've seen some pretty crazy things regarding limited aircraft procurement. For example, while working at the USAFA I've seen a fleet of motor gliders purchased because some IPs though a training program using motorized gliders would be a great idea. After spending a over a million bucks on this program, they were only used for a few years and it was discovered that just because you can fly an F-16 doesn't mean you can jump into a motorized glider tail dragger and instruct cadets. These aircraft were eventually surplused to other government agencies.

But to address the lack of an in-theater fixed wing transport - why when you now have heavy lift helicopters and the Osprey that can easily do the job???

 

[NVSMITH]

A few dynamics here -

I briefly worked around a C-123, you could put rocket engines on it and it's not going to out perform a C-130 except for getting into smaller airfields. The interior was a bit archaic, IIRC with the elevated flight station, the flight engineer sat on this seat that was hinged on the cockpit entry door and swung into position. I knew people who flew them as well as C-130s and the C-123 was not loved, especially the older Vietnam deployed units that made it into National Guard. However, for the era it was built and deployed, it was a good workhorse that supplemented early C-130 models.

The Caribous and Buffalo were great aircraft, but their time within in the Army was affected by top brass wrestling away mission requirements from each other. The Johnson-McConnel agreement is what took the fixed wing mission away from the US Army. Also consider that those in each branch of the US Military responsible for the planning and procurement of new equipment are usually limited in their assignments and those "think tank wiz kids" jump at the flavor of the moment. If they are reassigned, PCS or retire, a new group comes in and may set the envisioned mission and procurement requirement in a total different direction. I think about 150 Caribous were used by the US Army during Vietnam, just a handful of Buffaloes were operated by the US Army and USAF. I think all of these aircraft eventually wound up with the USAF who eventually retired them during the post Vietnam war period.

Another dynamic is something called "small fleet dynamics" in which the operator has to justify the operation of a small fleet as it perceived that operational costs will not justify the operation of such aircraft on a normal basis. As mentioned, I think there were only a "few" C-7s and C-8s being operated into the 1980s.

25 years plus working around some of these programs as a contractor, I've seen some pretty crazy things regarding limited aircraft procurement. For example, while working at the USAFA I've seen a fleet of motor gliders purchased because some IPs though a training program using motorized gliders would be a great idea. After spending a over a million bucks on this program, they were only used for a few years and it was discovered that just because you can fly an F-16 doesn't mean you can jump into a motorized glider tail dragger and instruct cadets. These aircraft were eventually surplused to other government agencies.

But to address the lack of an in-theater fixed wing transport - why when you now have heavy lift helicopters and the Osprey that can easily do the job???

-Thank you for providing first hand knowledge. All I ever did was ride in the back of the beasties!
-I agree about small fleet dynamics & won't get into the Key West agreements: Fiat G-91 in US Army markings anyone?
-Your last comment/question may be the most important. 1) I think that, from the Army standpoint at least, the issue of in theater fixed wing transports has never gone away, that is an indication that some senior folks think the idea has merit. 2) From what I've been told and have picked up over the years, the operating and maintenance costs, not to mention maintenance hours, heavily favor fixed vs. rotary wing. 3) This is a factor unknown to me: how does the service life, both age and number of flight hours, stack up for fixed vs. rotary wing? 4) I think that pound per cargo mile fixed wing trumps rotary wing in speed and haulage per aircraft.
-In practical terms the point may be moot anyway.

 

[FLYBOYJ]

-Thank you for providing first hand knowledge. All I ever did was ride in the back of the beasties!
-I agree about small fleet dynamics & won't get into the Key West agreements: Fiat G-91 in US Army markings anyone?
-Your last comment/question may be the most important. 1) I think that, from the Army standpoint at least, the issue of in theater fixed wing transports has never gone away, that is an indication that some senior folks think the idea has merit. 2) From what I've been told and have picked up over the years, the operating and maintenance costs, not to mention maintenance hours, heavily favor fixed vs. rotary wing. 3) This is a factor unknown to me: how does the service life, both age and number of flight hours, stack up for fixed vs. rotary wing? 4) I think that pound per cargo mile fixed wing trumps rotary wing in speed and haulage per aircraft.
-In practical terms the point may be moot anyway.

Agree about the rotary wing maintenance vs fixed wing bit at the same time you have to consider getting into a tight area vs pound per cargo mile, that's why the Osprey was good fit into this. Now as far as the Army - I think they will be stuck in the rotary wing world for a long time with regards to moving men and equipment until someone re-evaluates the Johnson-McConnel agreement.

 

[daviemax]

The C-123 had very, very poor stall characteristics and was very difficult if not impossible to recover from a stall, so any modifications to the aircraft would ideally address that issue.

 

[NVSMITH]

-Thanks for your reasoned response. In general I'm forced to agree; as I said initially, the issue may be moot.
-I did think of point #5 and am kicking myself. With respect to operations I think that rotary wing birds are more susceptible to combat damage.
-I'll go back to my belief that, based on my experience, in-theater transport is a need. My belief is that smaller than C-130 STOL or semi-STOL birds, and I don't mean Twin Otters, have utility.
-I don't have enough knowledge about the Osprey to comment but I have heard it is a maintenance bear. That may be the USMC folding blade and wing version vice the USAF SOS version.
-How about we just agree to disagree?

 

[GreenKnight121]

I looked at this a few years ago... and found more details of the C-123T upgrade (T56 turboprops, just like the P-3 Orion & C-130).

In other sources I found that one issue with any C-123 turboprop proposal was the severe lack of airframes that have not been contaminated by defoliant chemicals.

Both the T64 and the T56 were available by 1960... and since the C-123 remained in production until 1970, new-build turboprop examples could easily have been produced.

Do you have the specific model of T64 planned for the C-123L?
The Alenia G.222 (produced from 1970, bought by the USAF as the C-27A) used the 3,399 shp T64-GE-P4D... while the 1964 DHC-5 Buffalo used the 3,133 shp CT64-820-4, and the Kawasaki P-2J of 1966 (Japanese-built turboprop P-2 Neptune) used a Japanese-built 2,850 shp T64 version (plus boost turbojets).
As the C-123L proposal was in 1967 (thus before the most powerful T64 turboprop version), this engine might not be enough of an improvement over the 2,300 hp R2800s of the C-123B or the 2,500 hp R2800s of the C-123K to completely negate the need for the boost turbojets.

The T56-A-7 of the C-123T test aircraft produced 3,420 shp, while the production -Ts were to use the 4,590 shp T56-A-15.

 

[PStickney]

I looked at this a few years ago... and found more details of the C-123T upgrade (T56 turboprops, just like the P-3 Orion & C-130).

In other sources I found that one issue with any C-123 turboprop proposal was the severe lack of airframes that have not been contaminated by defoliant chemicals.

Both the T64 and the T56 were available by 1960... and since the C-123 remained in production until 1970, new-build turboprop examples could easily have been produced.

Do you have the specific model of T64 planned for the C-123L?
The Alenia G.222 (produced from 1970, bought by the USAF as the C-27A) used the 3,399 shp T64-GE-P4D... while the 1964 DHC-5 Buffalo used the 3,133 shp CT64-820-4, and the Kawasaki P-2J of 1966 (Japanese-built turboprop P-2 Neptune) used a Japanese-built 2,850 shp T64 version (plus boost turbojets).
As the C-123L proposal was in 1967 (thus before the most powerful T64 turboprop version), this engine might not be enough of an improvement over the 2,300 hp R2800s of the C-123B or the 2,500 hp R2800s of the C-123K to completely negate the need for the boost turbojets.

The T56-A-7 of the C-123T test aircraft produced 3,420 shp, while the production -Ts were to use the 4,590 shp T56-A-15.

I'm a bit puzzled - the last new production C-123 was accepted by the USAF from Fairchild in early June, 1958. Just after that, the 123s (And C-119s) were being replaced in Active Duty Troops Carrier units by C-130s. Most 123s were handed over to the reserves in '58-60. Some were recalled to active service in Air Commando Squadrons (Troop Carrier), which later morphed into Special Operations Squadrons, and, in about 1971, those that hadn't gone to Thailand or Vietnam, or had been lost, were issued to a couple of USAF Reserve Tactical Airlift Wings.
I flew on some of those (Out of Westover AFB) in the mid-'70s, and they were well and truly clapped out by then.
Anything with a later than a C-123B was a conversion of a B model.

 

[FLYBOYJ]

I'm a bit puzzled - the last new production C-123 was accepted by the USAF from Fairchild in early June, 1958. Just after that, the 123s (And C-119s) were being replaced in Active Duty Troops Carrier units by C-130s. Most 123s were handed over to the reserves in '58-60. Some were recalled to active service in Air Commando Squadrons (Troop Carrier), which later morphed into Special Operations Squadrons, and, in about 1971, those that hadn't gone to Thailand or Vietnam, or had been lost, were issued to a couple of USAF Reserve Tactical Airlift Wings.
I flew on some of those (Out of Westover AFB) in the mid-'70s, and they were well and truly clapped out by then.
Anything with a later than a C-123B was a conversion of a B model.

180+ C-123Bs were updated to C-123Ks during the early 1960s IIRC.

 

[GTX]

Old Wings - Fairchild C-123T Provider - The "Turbo Provider"

www.oldwings.nl