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AR15.COM
9/6/2014 1:51:34 PM EDT
I just heard that some planes had an inverted v-12 engine, like the bf-109.  What was the purpose of inverting it?  My guess would be it just fit better in the fuselage, or moved the center of gravity.
9/6/2014 2:47:34 PM EDT
[#1]
Think the BF109 managed to squeeze a 20mm cannon in the prop hub that way.  We did the same thing in the P-39 w/ a 37mm, but we had to put the engine in the back.
9/6/2014 2:59:38 PM EDT
[#2]
Better lubrication.  The oil flowed down from the crankcase instead of having to be pumped up hill...

I'm joking...
9/8/2014 6:33:29 AM EDT
[#3]
Kept the weight and bulk of the engine lower, and allowed easier access to the cylinder banks.
9/8/2014 5:37:21 PM EDT
[#4]
Inverted engines were more common than you think.  DeHaviland used them in the Tiger Moth.  We used Ranger engines in a couple of designs.  The design had been around for a long time.
9/13/2014 7:29:28 PM EDT
[#5]
Quote History
Quoted:
Think the BF109 managed to squeeze a 20mm cannon in the prop hub that way.  We did the same thing in the P-39 w/ a 37mm, but we had to put the engine in the back.
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Aero Cobra ... pilot had a driveshaft between his legs.
9/14/2014 11:29:10 AM EDT
[#6]
Proof that there is more than one way to design an engine.  Rolls-Merlin for the win though.
9/17/2014 2:47:30 PM EDT
[#7]
For direct drive props inverted V engines meant better visibility and shorter landing gear legs. Visibility was better because the crankshaft was near the top of the engine and therefor the cylinder heads were below the pilots line of sight so the engine cowling sight line was lower. This was especially important on the taildragger aircraft designs used during WWII. Also, because the crank was toward the top of the engine the propeller was higher off the ground which allowed for shorter main landing gear legs and better ground handling.

I think the issues with oil control and consumption (inverted piston skirts filling up with oil and crankshaft oil slinging) caused more problems then they solved and the advent of propeller reduction gearing resolved the prop clearance issue.
9/21/2014 10:19:36 PM EDT
[#8]
A lot of WWII planes had inverted V's but yeah, the Germans used them a lot.

I always thought it had to do with getting fuel to the manifold in inverted or other crazy maneuvers but I am not for sure. I had also read it was for ease of maintenance. Personally, I figured it made it easier to put two MG's on top of the fuselage but I really don't know.


10/8/2014 9:57:19 PM EDT
[#9]
Quote History
Quoted:
A lot of WWII planes had inverted V's but yeah, the Germans used them a lot.

I always thought it had to do with getting fuel to the manifold in inverted or other crazy maneuvers but I am not for sure. I had also read it was for ease of maintenance. Personally, I figured it made it easier to put two MG's on top of the fuselage but I really don't know.


View Quote


Bf109 was fuel injected, so no cares.

Spitfire was carbureretted, so that limited negative 'g' maneuver time, lest the engine starved for fuel.