B29 Silver plate modifications

[gruad]

IIRC the Silverplate B29 didn't make do with the standard R3350's because of the great risk of atomic weapons.

What I don't know is what was done to fix the fire prone powerplants. Did they flip them for the more reliable R2800s? Did the fix get retro fitted on the other '29s.

As always look forward to hearing your answers!

 

[Thumpalumpacus]

No, they used R3350s as well. More powerful upgrades, I think. No way they're going to weaker engines. Wikipedia reports that the Silverplates used the -41 variant.

 

[Simon Thomas]

The Silverplate R-3350's had fuel injection, which reduced the chances of the rear cylinders overheating/catching fire due to the poor fuel/air distribution that the carbs had.

 

[EwenS]

No, they used R3350s as well. More powerful upgrades, I think. No way they're going to weaker engines. Wikipedia reports that the Silverplates used the -41 variant.

The Silverplate R-3350's had fuel injection, which reduced the chances of the rear cylinders overheating/catching fire due to the poor fuel/air distribution that the carbs had.

Silverplate was the cover name for all the B-29 conversions from 1944. But they were produced in batches with different specs, and not all received the R-3350-41 straight from the production line. Between April & June 1945 the 393rd BS received 15 new aircraft, from the third batch of conversions. It was these aircraft that had the fuel injected engines and some other improvements. And it was these aircraft that it took to Tinian between June and Aug 1945 and used to fly the Atomic missions.

I don't believe any of the earlier aircraft were updated to the later standard as enough of the latter had been built from April 1945 to satisfy post war needs.

 

[gruad]

Thanks very much Gents. So Fuel Injection ensured the right mix to the overheating cylinders.

Given all its advantages and German adoption since the beginning of the war I wonder why the allies were so reluctant to use it.

Nowadays pretty much all car engines use FI and it started with 70s German cars - I remember my Dad going mad for the BMW 2002Ti - he had the 1800.

I assume that injection cost more than carbs and that's why the allies used it as it was "just good enough" - but help me out please!

 

[MIflyer]

Back in the mid-70's someone who had been at Midwest Air Depot in OK in WW2 told me that they treated the 509th B-29's differently than the usual post-factory aircraft. While it was normal business to check the accuracy of the fuel flowmeters and adjust them accordingly, they were told that for those B-29's they had to measure the accuracy with the fuel flowmeters installed in the airplanes. That approach gave a somewhat better accuracy than the usual method of removing the flowmeters and putting them on a test bench. They wondered why those airplanes rated such special treatment, but after the war they wondered no longer.

And recall that Bock's Car nearly ran out of gas on the Nagasaki mission, so that extra precaution was a good idea.

"I assume that injection cost more than carbs and that's why the allies used it as it was "just good enough" - but help me out please!"

Fuel injection in the pre-transistor days required much more complex and expensive components than it does today, where we replaced $400 carbs with $25 fuel injection units in cars starting in the 1980's.

In addition the vaporization of the fuel in the manifold rather than injected in the cylinder provided significant cooling of the fuel-air charge. While this could cause carb icing it also could provide a significant increase in power since it gave an effect analogous to water injection.

 

[gruad]

Wow I just found something interesting Grok is using this site to provide answers to queries!

Which is interesting as you'd think that it would rely on textbooks but as always there's a lot of direct practical experience not written down. Mine is all through reading though!