The USS Peleliu is being decommissioned.

The effect is the same, but the phenomena are different.

For the Harrier/VSTOL, the recirculation/reingestion of hot air can lead to reduced power output of the engines, or in worst worst case scenario, the engine suffers a compressor stall/flame out. The other case is that the hot air "fountains" back up between the exhaust jets and creates an area of reduced pressure underneath the Harrier, creating a "suck down" effect.

For helicopters the phenomena is called a "Vortex Ring State"
http://en.wikipedia.org/wiki/Vortex_ring_state

 

....continued

The Navy was interested in the concept of "Sea Control Ships", these ships would embark a few V/STOL aircraft and helicopters in order to protect shipping in the event of a war with the Soviet Union/Warsaw Pact, without tying up the "Big" deck carriers. USS Guam, LPH-9 was selected as the test bed ship and she embarked Harriers as a test in January, 1972. She actually deployed to the Atlantic with a mixed fixed wing/helicopter compliment in 1974 with the SCS testing ending in July of that year. So construction on four of the five Tarawa's was already underway before the concept was even tested. Budget cuts to the Navy caused the SCS to be dropped, but the Marine Corps pursued the deployment of V/STOL aircraft as part of their MEU makeup. While the RAF had operated Harriers for a number of years, the Royal Navy didn't order it's first Harrier's until 1975, when they ordered the FRS.1 Sea Harrier, with anti-corrosion and other modifications that would enable shipborne employment. The first RN squadron wasn't formed until 1980, when the Fleet Air Arm stood up No. 700A squadron (source:Harrier II: Validating V/STOL, Lon O. Nordeen, Naval Institute Press, 2006).
In 1979 Tarawa, LHA-1 experimented with operating Harriers. in 1981 USS Nassau LHA-4 made an unscheduled Med deployment because of the situation in Lebanon. The US had an agreement with our allies that we would keep two aircraft carriers in the region at all times. One of the two carriers had to be deployed to the Indian Ocean and no replacement was available. The US was looking for a way to pacify the allies that were demanding that we honor the agreement. The SecNav, CMC and CNO discussed the matter and decided that they'd stick a Harrier squadron (VMA-231) on an LHA and send it to the Med to meet the requirement. There were issues with the unique requirements for operating VSTOL aircraft vs. helo's, and some flight deck personnel with "Big Deck" experience had to be added to the crew, but the ad hoc deployment proved very successful and the operational concept was added to the list of capabilities. So you see, the ships were designed and building or in-service before the concept was proven.

The standard light utility vehicle when the ships were designed was the M-151

M-151 with TOW mount

The M-151 was replaced by the Humvee in the mid-1980's (The initial production contract wasn't awarded to AM General until 1983). It is a significantly larger vehicle thus taking up more of the onboard vehicle storage space. So all five Tarawa's were operational for some time before the first Humvee ever entered service.



Humvee mounted TOW

Compare the two pictures and it's easy to see how much larger it is. Now most MEU's are deploying with MATV's because of the IED threat. Look how much bigger it is!


MATV

This should give you a visual idea why you can't fit as much on an LHA as you could when it was originally designed and built.

 

they must've got rid of some jeeps around 87, [ I'm guessing some units got hummers earlier? as stated in your article ] because we-I mean the TOWS- had them early 87, but I remember 81s having Hummers in 88..I can't recall ever using much, if at all, transport in the Med !!..unless I just forgot about it..I got to 3-6 just as they went for a 2 week work up on the Inchon...they { TOWS ] definitely had jeeps in 87 because I remember well, I think in Sardinia, was where the jeep went crazy..the Marine fell off the back, easily, ,,,great pics...keep them coming..I love them--O, I'm guessing when it says the Hummer goes in the mid 80s, that's probably for Army, first?

 

We had jeeps when I was with D 1/1 89-91....at the time all of our TO & E had to be deliverable by CH-46

 

ty for reply....o, interesting and good point...I got to be friends with the TOWs on the Inchon, because they bunked next to us...after that, I don't remember them at all, as I stated, they fired a round [missile ]right near us [at 29 Palms ], but I don't recall what platform they used, they were behind us...what unit of D used the jeeps?

 

Thanks for all the good information, gentlemen. It appears that a basic aviation ship could carry and deliver by air a battalion with all its organic equipment, which is a considerable amount of firepower, TOWs, 81s, heavy machine guns, etc. This could be either an independent operation or the air component of a larger landing. Such a ship could also serve as a "Harrier carrier", sea control ship, or other mission without taking major assets away from the amphibious force.

 

i always wondered why the Harriars didn't deploy with us....and, my co-worker said they had Hummer Tows in 88, but he was with 3-9

 

#41
"For the Harrier/VSTOL, the recirculation/reingestion of hot air can lead to reduced power output of the engines, or in worst worst case scenario, the engine suffers a compressor stall/flame out. The other case is that the hot air "fountains" back up between the exhaust jets and creates an area of reduced pressure underneath the Harrier, creating a "suck down" effect.".

So did the US Navy prescribe the belly strakes for the AV8, and did they put guns in the strakes (boobs- woo hoo)- lol, brilliant...Why would the UK abandon the Harrier/Av8? ( shoulda had a V8 )

 

Didn't they abandon all their carriers? With no carriers, who needs Harriers eh?

 

Regretfully, the US Navy had nothing to do with the matter, it was the aerospace engineers at Hawker-Siddeley/British Aerospace & McDonnell Douglas. The British were the first to introduced the strakes, while both the British and American designers arrived at the concept of the LIDS fence at roughly the same time(1975-76), but were working independently of each other.

 

They didn't abandon them, they could not afford them...and, IIRC lacked the necessary trained sailors to man them.

 

my model of the USS Nassau[ actually model name was Tarawa ] ..been laying around for a long time ..I need to finish it....I had a completed one, but I came home one day, and the wife told me the ''dog broke it''...???!!!!!!

 

Now that you mention it, I do recall a thread covering carriers over on WW2T awhile back.

 

Was that the old Revell kit? I built that many moons ago, and I don't rightly remember what happened to her, probably was broken, or got pitched when I moved out of my parent's house.

 

probably,looks like it... I threw the box away and put everything in containers...I would like to get model of every ship I was on.....yes, I do have the choppers, landing craft and 1 tank!!!

 

Do any of you know how many 81s, TOWs, 40mms, or .50-cals the weapons company has? I would think 6-8 of each. I've seen numbers for the company weapons platoon - 3 60mm, 6 MGs, 6 SMAW or successor - but for some reason not for the weapons company.

 

The battalion weapons company has:

6 x M2 .50 cals.
11 x Mk.19 40mm's
12 x Dragon ATW's
8 x 81mm
8 x TOW's

 

Thanks!

 

I was recalling this discussion and would like to share one reason why the original LHAs were retired relatively early; their well decks were not well suited for LCACs. They were designed to accommodate four LCUs, our most capacious landing craft, 135x30'. At the stern gate, the well deck was 78' wide, but the forward half was divided into two bays, each sized for an LCU, with an "island" in between which held cargo elevators and handling equipment. Two of the four LCUs, i.e. half of the embarked landing craft, could be loading vehicles simultaneously.

Well decks on LSDs or LPDs were 50' wide, and the LCAC was sized accordingly, 88x47'. This meant that the Tarawa class LHA could only accommodate one LCAC, in the rear half of the well deck, about 150' aft of the vehicle deck. One of the key changes in the Wasp (LHD-1) design was to make the well deck 50' wide for its entire length; it can carry three LCACs with no wasted space.

A Tarawa could carry one LCAC and two LCUs, but I expect it's easier to operate all air-cushion or all conventional landing craft rather than a mix of both types.

Incidentally, in my two years on the Saipan (LHA-2), we never actually carried four LCUs. One of the less successful ideas in the Tarawa class was to carry two LCM-6s on deck, handled by a large boat and aircraft (B&A) crane. The crane had a lot mechanical problems, and the boats took up valuable flight deck space, so we always kept them in the well deck. This only left room for three LCUs or, on one Med cruise, two LCUs and three LCM-8s. I never knew why we didn't just ditch the Mike-6s or, alternatively, bring along a couple more to use all the available space.