Rolls Royce Merlin exhaust angle on early Spitfires

[thierry laurent]

Hi, 

 

I have a problem to position correctly the early tubular exhausts on a Spitfire MkI. Pictures and plans of the engine front view clearly indicate a noticeable angle. Have a look here for one example:

http://jn.passieux.free.fr/html/Merlin.php

 

However, scale plans of the plane including the following one show a nearly horizontal stance in comparison with the datum line:

 

Does anyone have more precise info? To me it looks they were clearly angled! 

 

Weird! 

 

Thierry 

[chuck540z3]

These pics might help.

 

 

 

 

They look mostly horizontal to me.

 

Cheers,

Chuck

 

 

[thierry laurent]

Thanks but from such angles it is not possible to assess for sure. I had the same problems with the pictures I looked at. Only a front view in front of the spinner could give a final reply. 

[thierry laurent]

That one is a rare picture with the nose at ground level and in a more horizontal position. To me the end of the last pipe indicates some angle:

https://i.pinimg.com/originals/36/08/4a/36084ab5137586b218ceda460a2f22e5.png

[BiggTim]

I would vote a slightly downward angle of 2-3 degrees to my eye.

[LSP_K2]

Given that the cylinder head banks were canted outward, and assuming the exhaust pipes were perpendicular to those, yes, a downward angle makes perfect sense.

[thierry laurent]

55 minutes ago, LSP_K2 said:

Given that the cylinder head banks were canted outward, and assuming the exhaust pipes were perpendicular to those, yes, a downward angle makes perfect sense.

That is what I concluded as well. However, I was puzzled when I looked at the planes plans from different sources as well as many models (but the latters are possibly based on the formers). 

[LSP_Ron]

I'd say flat?  I think the seam at the back is throwing the eye to think a downward angle

 

 

 

 

 

[LSP_K2]

Those all look downward pointing to me, Ron, but that's just me.

[thierry laurent]

Funny to see that things we are seeing for years and taking for granted can be so confusing as soon as we try to look closer...!     

[chuck540z3]

These close-ups might help a bit.  Note that the center-line of the exhaust appears to be angled down slightly.

 

 

 

 

From this rear angle, however, they look pretty flat.

 

 

 

 

Cheers,

Chuck

Edited January 23, 2020 by chuck540z3

[thierry laurent]

This is the typical problem of the bottom views! The only way to be fully sure would be a picture taken from the propeller front level. I'm also wondering if the exhausts are not slightly twisted if you compare the relative position of all exhaust holes. 

[Trak-Tor]

I'd say going just slightly downwards. Definitely not straight out of the holes in the engine block like in that Merlin drawing above.

Pictures from David Whitworth's Flickr:

 

1011:G-AIST / P7308 by David Whitworth, on Flickr

 

0180:G-AIST / P7308 by David Whitworth, on Flickr

 

0181:G-AIST / P7308 by David Whitworth, on Flickr

 

I hope that helps a little.

 

Juraj

[RLWP]

 

They're a lot bigger than you might think!

 

I've got one of those air compressors somewhere

 

Richard

[thierry laurent]

I know Jennings but this is typically what I do not see in pictures.

 

If you have a look at the drawing, you see an horizontal section going out of the fuselage sides, then a downards bend and finally the exhaust ends that are going down. I do not see that on the full scaled parts. There is just a rounded slope going from the start of the exhaust up to the tip as the last picture posted by Chuk clearly shows it.