From: Zagreb, Croatia
I cant find any specifics but by Oct. '44 (3 months after landings and 2 months after construction began) B-29 were arriving and by late November were operational.
Maybe the results aren't that far fetched after all.
By mid-August 1944 Tinian was secure, and American Seabees began rebuilding a captured Japanese air strip at the north end of the island in one of the largest engineering projects of WWII. Less than one year later North Field was the largest airfield in the world, with four vast 2,600 - meter runways and a total of 19,000 combat missions launched against Japan.
Tinian got a face lifting which made it one of the most important bases of the war. On this remote rock, Seabees of the Sixth Brigade built the largest airfield in the world, larger even than Mayor LaGuardia's proposed Idlewild airport at Long Island which FORTUNE magazine (April 1945) had called the "biggest in the world." The total area of Idlewild wasn't even as large as one of the two parts of the B-29 field the Seabees built. The runways at Idlewild measured at 14.5 miles. Tinian North was almost 20 miles long. Tinian West is only a fraction smaller. Width of runways at "world's biggest airport" is only 300 feet. Large enough, but Tinian's measured from 425 to 500 feet.
The Seabees did all the construction on Tinian. No Army Engineers were there, as were on many of the previous jobs which were done jointly. Battalion builders hauled, blasted and packed down enough coral to fill three times the volume of Boulder Dam-nearly 112 million cubic yards of filling. And along with the airfields came the inevitable barracks, hospitals, chowhalls, BOQs, wells, warehouses, and chapels.
Tinian is about the same size and shape as Manhattan, and when U.S. forces occupied it during the war, they laid out a system of roads with the same general plan and orientation as on Manhattan. To carry the huge quantities of bombs up from the port at San Jose, two divided highways were built across Tinian. The GIs gave the roads names like Broadway, 8th Ave., and 86th street. The main north-south road, is Broadway, and it runs parallel to the other main north-south road, 8th Avenue. The fact that Tinian has streets named after streets in New York City has no connection with the Manhattan Project.
As soon as air service groups prepared the bases for occupancy, hundreds of B-29s began arriving in October and November, ready to undertake strategic bombing operations against the Japanese home islands. An airfield was ready for the first B-29 strike on 24 November. Camps on Tinian were constructed to house 50,000 U.S. troops and 1.2 million pounds of crops were produced, all of which were consumed on the island. By August 1945, a year after construction started, Tinian was the largest airbase in the world at the time, and accommodated nearly 1000 B-29s.
During the last two months of 1944, B-29s began operating against Japan from the islands of Saipan, Guam and Tinian. Initial bombing missions were flown during the day at high altitude, concentrating on chemical plants, aircraft factories, harbors and arsenals. Gen. Curtis LeMay studied the poor results and instructed the bombers to begin low-level incendiary raids at night. The raids targeted Tokyo and some of Japan's other major cities, Nagoya, Osaka, and Kobe.
Hmmm... I don't know... more confusion...
In your text it says that final size the Tinian reached in 12 monts (August 1944 - August 1944).
In WitP-AE the largest Airbase size is 7.
I made Airbase from 0 to 7 in 45 days using 10 SeaBees units...
According to WitP-AE manual B-29 requires Airbase 7 to operate.
Prior Preparation & Planning Prevents Pathetically Poor Performance!
A & B: WitW, WitE, WbtS, GGWaW, GGWaW2-AWD, HttR, CotA, BftB, CF
P: UV, WitP