How the US Army could have used the UH-1D/H as a gunship (but didn't)

Ray,

Great post. So that's where Revell got their gunship from.

Rich

Rich,

  That was exactly what I thought.  One day I'd like to do a "what if" bird with all the bells and whistles.  The TM also indicated that teh XM-157 7 shot rocket launcher was to be used as well, but those pages were messed up in the document scanning process.  Would one of our resident Huey drivers mind telling me how a H model equipped with the M-5, M-21, and M158 systems would perform?  could it get off the ground?  I think at least the space problem for ammo and such would not be an issue with a H model.

      Ray

The hardpoints on the UH-1D/H were built into all the airframes. The usefulness of these hardpoints is reflected in the maintanence and operators manuals under the headings of special missions equipment. You haven't even gotten close to what the UH-1 could carry, beyond the illustrated weapons. Other operators such as RAAF and RVNAF utilized the weapons first because the US wasn't giving away gunships and because the other users were buying fewer airframes and wanted maximum flexibilty in what they bought. If the US Army had INTENDED to use the UH-1D/H as a gunship they would never have continued using B/C/M airframes, never authorized the AH-1G or considered the AH-56. The clear role for the UH-1D/H in the US Army was support.

There is much commonality of airframe parts between the models of the UH-1 series. Shared parts make production more efficient and less expensive. 

Chief Snake 

Gotta go with the Chief here.  Sounds to me like the original qualification of the D/H model included the weapons, but the US Army never fielded it.  Adding weapons gave those poorer nations dual-role capability, while Uncle Sam went with the Huey for support and developed dedicated gunship airframes.  I'll give you another example - in the '80s, there was a program to provide Stinger air-to-air missiles on all Army helicopters.  I ran the program for Cobra.  We developed and qualified the mod, but it was never fielded.  Nevertheless, you can find an approved mod kit (MWO) to add Stinger to a Kiowa or Cobra.

Dan H.

I've heard through the grapevine of my hidden in the dark SOAR clients that the MH-60L armed helicopter commonly called the DAP, has a variation called IDAP. Improved DAP. That has the Stinger to airframe mod used on the upper ESSS hardpoints. Also heard that it is AIM series capable just like the Marine AH-1W. Haven't seen a photo of it mind you, but the speaker about such oddity is right where the action is and hasn't given me any reason to doubt him. Bet something you worked on made it through the pipeline to those fellows on the dark side.

Chief Snake 

Chief,

  If the US NEVER intended to use the D model in the gunship role, why would they intentionally put hardpoints and connections (these are more than just attachment points, but electrical connections and wiring for weapons) for US weapons systems?  Also, why put the info on arming birds in the 1965 (at least) maintenance manual?  I'll give you that the US never OFFICIALLY adopted the D model gunship, but there are any number of photos showing that weaons systems were tested on the D model airframe.  granted it was the YUH-1D for the most part.  To be honest with you I think the Aussies had a great idea.  Why did we use uderpowered, loaded to capacity B models that could barely take off wheh we could have used D's instead.  I know the D/H was needed as a troop transport, but it couldn't be that much more expensive to make the Deltas and they could carry more ammo and weapons instead of continuing to make B's and C's.  I'm sure everyone has an opinion on this, but does anyone know what the OFFICIAL US policy was on gunships?  It just seems to me like the insistance on using B models as gunships instead of the more powerful D/H models is yet another symptom of how screwed up things were during the VN years.  

    Ray
 

I changed the Title of this thread to more accurately confer what I meant in the first place!  By the way, my main intent was to show why armed UH-1D/H models have the rockets mounted on the rear set of hardpoints and any that have guns have them on the front set of hardpoints.  This also helps explain why the rockets and guns are mounted seperately on D/H model birds instead of together like they are on B and C models.  that's what I meant by the REST OF THE STORY comment.

   Ray
 

It's fairly simple to see what the army intended. Just follow the historical developement from A to B to D to H and the paths intended for each aircraft is obvious. Remember, flexibility is a very desirable trait and being able to do it doesn't mean that you intend to keep doing it once you've established you can. The US was/is a leading aircraft and weapons making country and those get sold to many other countries. The armed forces of those countries take great stock in how the US military and industrial machine work and they are quite willing to buy into the results. The UH-1 series started out as a troop carrying helicopter. The need and ability to arm it became obvious when it came into use in an armed conflict. The limitations of cabin size in the utility role dictated the size expansion, not for needs of weapons carrying but for more effective troop carrying capacity. The changes to primarily gunship roles took an entirely different path. The hardpoints have a basic role in the aircraft, to allow attachment of external loads. The variation of weapons combinations fitting those hardpoints is a selling point to those customers who sought flexibility in their airframe purchases and also placated the desire for gunships. Search further into the hows and whys and whats of the gunship's history you'll note that we didn't sell military UH-1/AH-1 gunships to anyone during the 60's and early 70's. This is twofold, the US needed what production was available (not just for Vietnam but for worldwide US Army modernization) and because the development was ongoing through several practical iterations. You cannot ignore politics in this, it has a very clear effect. It still impacts weapons systems and aircraft developement to this very day. Think about it and you'll be able to verify what I'm saying when you take anything the US has developed and then see the curve in when and who was able to buy it later. With both limitations to the systems or customer specified substitutions within the systems. 

Also consider that the organization of other countries armed forces do not necessarily mimic ours to the letter. The very basic allotment of troops in an organization can alter the way one buys equipment. The maintanence books show the installations because they are valid. The people who use the aircraft outside the US also use the same books. Wiring harness locations are simply that, locations. What gets plugged in each end of the wiring harness can be anything, eh?

Chief Snake 

Ray,

Great post mate! Thanks for sharing ya finds

A few questions..

From what you guys have said, am i right in gathering that as the US wasnt selling Hueys to other countries during the war years. The motivation behind adding hard points to the YUH-1D was more about giving the Army the option to add weapons to any or all hueys in Vietnam if need be and less about the prospect of future international sales?

Were the armed 9 Squadron and VNAF D&H models a direct result of the US not handing over B&C models ?

With its more powerful engine and larger carrying capacity, could a D&H model be a better option and out perform the B&C model huey in the role of a gunship?

Andy

Andy,

 "From what you guys have said, am i right in gathering that as the US wasnt selling Hueys to other countries during the war years. The motivation behind adding hard points to the YUH-1D was more about giving the Army the option to add weapons to any or all hueys in Vietnam if need be and less about the prospect of future international sales?"

     Yes and NO.  the US sold plenty of UH-1D/H's to other countries, but (as Chief said) no B/C gunships.  I'll post some specific dates and contract orders published by Bell a little later.

 "Were the armed 9 Squadron and VNAF D&H models a direct result of the US not handing over B&C models ?"

Bell Helicopter recieved an RAAF order for 8 model 204B's on April 17, 1961.  that's the closest thing to a B model gunship I can find that ever went to the RAAF.  However, since the 204B is civilian I assume there was no provision for armaments. 

  If you haven't already read it, check out this article by a former Bushranger armorer.  If anybody knows the truth about the hows and whys it should be one of the guys who did the mods!   

http://www.hotkey.net.au/~marshalle/raaf/bushranger.htm

I must confess after reading this story that I'm not even sure the Aussies realized the UH-1D/H had equipment onboard to facilitate weapons installation.  The portrayal of the "Yanks" is a bit over the top as well, I think.  after all, there would have been no helos, guns, or ammo without the "Yanks!" 

"With its more powerful engine and larger carrying capacity, could a D&H model be a better option and out perform the B&C model huey in the role of a gunship?"

That's the question I can't seem to get an answer to.  All indications to me are that the UH-1D/H culd fly circles around the Bravo.  After all, in 1962 a YUH-1D set all kinds of records including speed and time to climb.  one would think that a UH-1D/H with it's greater rotor diameter and more powerful engine would beat an equally loaded Bravo every time.  I think that Chief Snake may be on to something, though.  Since the Army was after a dedicated gunship, it would be a lot easier to argue the case if your current gunships weren't up to the task.  had they gone with UH-1D/H model gunships, they might not have been able to make the case for a dedicated platform for the attack role.  Just a thought, but I think worth considering.  

   Ray

The lift capacity is determined by the engine SHP and the rotor system it is harnessed to. The UH-1D/H empty weight was 4700lbs, gross weight 9500lbs. That essentially means that it could have 4800 pounds added to it's airframe and still fly. Typically, armored seats add 400lbs, guns and minimum ammo 400lbs, fuel 1400lbs, crew 800lbs for a total of 3000lbs. Now we have a gross weight of 7700lbs on a 9500lbs max airframe giving an additional add on weight of 1800lbs.

The UH-1C weighed in at 5800lbs. Max gross weight, 9500lbs. Fuel, 1000lbs add seat armor 400lbs and crew weight 800lbs for 7900lbs. That leaves 1600lbs for additional weight-the armament systems. The UH-1B was 1000lbs less at empty and gross weights.

The UH-1M weighed in at 5100lbs and grossed out at 9500 lbs. So it's ability for armaments/load increased 700lbs over the UH-1C.

The UH-1D and UH-1C originally used the -11 engines rated at 1100 SHP. The -13 put into the UH-1H and UH-1M had 1400 SHP. This improved the operating limitations for the aircraft it was put into but it didn't alter the load carrying capacity.

In the roughest of terms, the range of load available for the UH-1 series of aircraft basically was 1800 to 2200 lbs. No matter which aircraft it was on, the only way to improve the load range was to decrease the basic operating weight. For the UH-1H that is typically 7600lbs without armament and the UH-1M 7300lbs without armament.

The UH-1B was substantially less able to carry a load and the UH-1C improved this to a helpful degree.

The difference in the lift capacity was narrowed between the C/M gunships and the D/H lift ships by increasing the blade chord of the 44' C/M to 27" from the basic 21" chord of the 48' rotor system. The square footage available to "grab" the air is what gives the rotor system its lifting capacity.

Chief Snake 

Chief,

  Now that's what I'm talkin' about!  Thanks for the info!  At least now the civilians and non-aviators around here know what's what.  GREAT STUFF!!  Most informative and appreciated.

     Ray
 

Chief Snake wrote:

The lift capacity is determined by the engine SHP and the rotor system it is harnessed to. The UH-1D/H empty weight was 4700lbs, gross weight 9500lbs. That essentially means that it could have 4800 pounds added to it's airframe and still fly. Typically, armored seats add 400lbs, guns and minimum ammo 400lbs, fuel 1400lbs, crew 800lbs for a total of 3000lbs. Now we have a gross weight of 7700lbs on a 9500lbs max airframe giving an additional add on weight of 1800lbs. The UH-1C weighed in at 5800lbs. Max gross weight, 9500lbs. Fuel, 1000lbs add seat armor 400lbs and crew weight 800lbs for 7900lbs. That leaves 1600lbs for additional weight-the armament systems. The UH-1B was 1000lbs less at empty and gross weights. The UH-1M weighed in at 5100lbs and grossed out at 9500 lbs. So it's ability for armaments/load increased 700lbs over the UH-1C. The UH-1D and UH-1C originally used the -11 engines rated at 1100 SHP. The -13 put into the UH-1H and UH-1M had 1400 SHP. This improved the operating limitations for the aircraft it was put into but it didn't alter the load carrying capacity. In the roughest of terms, the range of load available for the UH-1 series of aircraft basically was 1800 to 2200 lbs. No matter which aircraft it was on, the only way to improve the load range was to decrease the basic operating weight. For the UH-1H that is typically 7600lbs without armament and the UH-1M 7300lbs without armament. The UH-1B was substantially less able to carry a load and the UH-1C improved this to a helpful degree. The difference in the lift capacity was narrowed between the C/M gunships and the D/H lift ships by increasing the blade chord of the 44' C/M to 27" from the basic 21" chord of the 48' rotor system. The square footage available to "grab" the air is what gives the rotor system its lifting capacity.   Chief Snake

And it is largely in this that we encounter the Model 209, reducing all that forward fuselage weight, enabling the installed powertrain to lift as much useful load in the hot/high climate as possible.  Had the US Army decided to follow the RAAF path and convert some of its slicks to hogs you would have had a supplemental fire support platform that would lessen the load on the Snake crews.

Ray, as far as mounting the rockets aft, that is a CG issue. The basic gun up front does not decrease in weight, but with each rocket fired from the launcher group you are changing your mass. You want that change to be as close to your mast as possible for CG shift compensation.  That and rockets produce a lot of crap out the exhaust end that would eventually foul a gun mount in the slipstream.

BTW got something nice for ya from the Nats!

David 

David,

  thanks for the info.  we missed you at the meeting last week.  we had a greta time, but it wasn't the same without you there.  Can't wait to hear about the Nationals!

     Ray

skypirate1 wrote:

Ray, Great post mate! Thanks for sharing ya finds A few questions.. From what you guys have said, am i right in gathering that as the US wasnt selling Hueys to other countries during the war years. The motivation behind adding hard points to the YUH-1D was more about giving the Army the option to add weapons to any or all hueys in Vietnam if need be and less about the prospect of future international sales? Were the armed 9 Squadron and VNAF D&H models a direct result of the US not handing over B&C models ? With its more powerful engine and larger carrying capacity, could a D&H model be a better option and out perform the B&C model huey in the role of a gunship? Andy

9SQN used the H moddel as gunships, as by that stage all the B/C's were all replaced. The Bushranger gunships were a brilliant idea, and most of the parts and the miniguns had to be srcounged/stolen/bartered for as the miniguns were never issued/bought by our military! Typical aussie workmanship!

And last night, 3 UH-1H's did one of their last fly by's in Brisbane. They will be phased out very soon. Very sad to see them go.

Grimmo,

  They better take good care of those retired Hueys.  One day, when all the technological wizardry fails us, we may need them again!  what is the RAAF replacing the Huey with?

     Ray

The Kioa's and huey's have been replaced with the Tiger. Troop transport we have Blackhawks, and will have MRH-90's soon.

Hey, talking about old tech, our F-111's are still flying! Saw 2 of them do a dump and burn over brisbane last night!