As far as I know the fires in AH are fuel tank fires. This to me means that fires on the b29 should probably not be over abundant since (unless I am wrong and ti does happen alot) the fuel tanks are self-sealing. Now this does not mean that they should never catch on fire in AH but I would think that it would not happen as much as it does but then I have only shot down one so far, so I would not say that I am a witness to the frequency of fires being B29's demise.
Judging by the screen shots, those sure look like engines on fire to me.The 2,200 hp Wright Cyclone R-3350 twin row radial engine was the primary problem. They tend to overheat, swallow valves and even catch fire in flight. I'm pretty certain that a bb gun, with enough velocity, should be able to light up the magnesium crankcase. They used magnesium to get more HP while reducing the weight. Magnesium is strong stuff, very light but its flammable as heck. (I watched a few guys catch grinders on fire at Boeing during my 30 years on the shop floor ...just from friction of removing burrs from magnesium parts. *Once a guy BUFFING magnesium with a buffing wheel caught it on fire!). They had some work arounds late in the war (cooling air to the cylinders, etc.) but I believe it's pretty easy to light up and magnesium-metal crank case with bullets.
*Once, this new hire took some "identified" magnesium parts (they had a big red tag on them) and decided to remove the burrs with a shop grinder. They had a big bucket of water near the grind to dip parts in when they got hot. This fellow started a magnesium fire and then threw some water on !
![Hehe! :lol](http://bbs.hitechcreations.com/smf/Smileys/default/laugh.gif)
Man, was THAT a good fire!
![dancing banana :banana:](http://bbs.hitechcreations.com/smf/Smileys/default/banana.gif)