B-29 APU restoration and first engine start in 30 years!

[B29Gunner]

Well friends, it looks like Photobucket has ruined all the fun, as apparently I've exceeded my bandwidth limit! I'll be moving all the pics over to a new host in the days to come, and then it will be back to our regularly scheduled programing

[Xray]

Looks like photobucket is not cooperating.
If you don't want to pay the $25 fee for reasonable storage space, this might be a good option

http://postimage.org/

[DH82EH]

I just discovered this thread.
Really enjoying it.
Thanks

Andy Scott

[B29Gunner]

Well the Photobucket pics are back up for the time being--until I exceed by bandwidth again! I'll try to get them all moved before that happens again, but for now, let's pick up where I left off and talk about crankcase ventilation on the V-32 engine!

Now for those who aren't familiar with why the crankcase needs to be ventilated, the simple explanation is this: all piston engines generate blow-by, which is when hot gases in the combustion chamber escape past the piston rings and enter the crankcase (not to be confused with valve blow-by, which is a whole nother issue). In severe cases, where the piston rings and cylinder walls are badly worn, you'll also get fuel and other contaminates entering the crankcase and contaminating the oil. All of this can ultimately lead to the destruction of the piston and the cylinder itself, but for this post, we'll just stick to the combustion gases! Unless these gases are vented, they will build up inside the crankcase and cause oil leaks (that pressure has to go somewhere!), as well as affecting the overall performance of the engine. Over time, you'll also get a nasty buildup of oil sludge as well.

The solution that the designers of the V-32 engine came up with for ventilating the crankcase was pretty ingenious, and I'll quote it directly from the manual:

"The system when operating, ventilates the interior of the engine and maintains a negative pressure in the crankcase. When the engine is operating, cooling air flowing through the scroll creates a negative pressure in the breather tube which opens the breather valve in the oil filler neck exposing the crankcase to the negative pressure. At the time this negative pressure is induced in the crankcase, the ventilating valves on either side of the crankcase which are controlled by calibrated springs, permit air flow originating at the rocker box vents, to pass through the rocker box vent hose to the crankcase. Sufficient air flows to ventilate the engine interior, but is so controlled that a constant negative pressure is maintained. It is when this negative pressure is destroyed, usually through malfunction of the valves, that positive pressure is built up and severe oil leakage develops at various places in the engine."

Now let's take a look at the various components of the system.

The breather tube:



Here's where the breather tube connects to the scroll.



And the one-way valve on the oil filler neck:



Here we can see the rocker box cover vents and hose, and another sophisticated graphic of the airflow









And finally a "ventilator valve" (one-way valve).



In the next update, just as soon as I can sit down to go through all the pics, we're really going to get our hands dirty and dig into this engine! Well, I'm going to get my hands dirty, while ya'll just sit back and watch Stay tuned!

[B29Gunner]

I just discovered this thread.
Really enjoying it.
Thanks

Andy Scott

Thank you! I'm having fun "spreading the knowledge," and I hope this thread will benefit others who also have one of these engines. And for anyone out there who wants a real "warbird project" to work on, but one that's also inexpensive, a B-29 APU would be it! Plus, they're really loud and will drive the neighbors crazy, and what can be better than that??

[B29Gunner]

Well friends, I've fallen way behind on updating my progress with the APU--so many pictures to sort through, and so little time!

But in the meantime, today was a very important day for both the B-29, and the world.

August 14th, 1945, was the B-29's last bombing mission of WWII. At 3:39am on August 15th, "The Uninvited," a B-29B flown by Captain Daniel Trask of the 502nd Bomb Group, became the last B-29 to drop its bombs on Japan. Later that morning, President Harry Truman announced that the Japanese had surrendered, and many B-29s were still in the air returning from their missions. "The Uninvited" was also the last B-29 to return home after a total flight time (non-stop) of 16 hours and 45 minutes!



"War Ends!" This was the front page of the Saipan Beacon newspaper on August 15th, announcing that Japan had surrendered and the war was finally over. "Victory and peace, paid for with blood and toil, were ours; home and loved ones were close to all."



Later that day, on August 15th, the last remaining original members still serving with the 19th Bomb Group (now a B-29 group stationed on Guam) got together to pose with a very special flag. The flag had been flying over Clark Field when the Japanese attacked on December 8th, 1941, and was later smuggled out of Mindanao aboard a submarine before the Philippines fell. The flag stayed with the 19th Bomb Group until the end of the war. (If anyone knows what became of the flag after the war and where it is today, please let me know!) Most here are probably familiar with the 19th Bomb Group's most famous pilot, Captain Colin Kelly, who paid the ultimate sacrifice when his B-17 was shot down on December 10th, 1941, after attacking a Japanese cruiser.

[B29Gunner]

Happy VJ Day!

"Let us pray that peace be now restored to the world, and that God will preserve it always." ~ General Douglas MacArthur, 2 September 1945.

Newsreel of the Japanese signing the Instrument of Surrender: https://www.youtube.com/watch?v=p7REAvk0iJQ

President Truman announces that the Japanese have signed the Instrument of Surrender: https://www.youtube.com/watch?v=Qf8YqaFZjak

[super14j]

All I can say is wow.. Very interesting thread about the B-29 APU. Thank You for sharing this...

[B29Gunner]

Happy Birthday to the Boeing B-29 Superfortress, whose first flight was 72 years ago today!