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Scimitar F1

Tempest Dihedral

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As the proud owner of Special Hobby’s Mk II,V and VI this subject has been vexing me for a while.

 

I have seen lots of builds and on most there appears to be virtually no dihedral overall which does not match photographs. So I went to the RAF museum at Hendon and had a good look at both marks there. From standing directly in front and directly behind the Mk V it appears that the inner sections of the wings are horizontal with neither anhedral or dihedral with the dihedral starting around the point where the undercarriage attaches.

 

Is this correct and has anyone else noticed this?

 

Will

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14 minutes ago, Scimitar F1 said:

Is this correct

yes

14 minutes ago, Scimitar F1 said:

and has anyone else noticed this?

Most other models have from memory.  72nd heller and old tool 48th Eduard for sure.

 

16 minutes ago, Scimitar F1 said:

As the proud owner of Special Hobby’s Mk II,V and VI this subject has been vexing me for a while.

 

I have seen lots of builds and on most there appears to be virtually no dihedral overall which does not match photographs.

If so, at least the solution is easy enough, a cut in the inner outer wing join, and bend up to the required dihedral (I don't have the SH kit, but that's what I try first if as described)

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12 hours ago, Scimitar F1 said:

Is this correct and has anyone else noticed this?

 

Yes, others have noticed it- the wing dihedral (in general, not necessarily midsection vs. outer panels) on the 32nd kits has been mentioned as a problem area.  I can't give you links to good discussion offhand, but after reading your question this morning I just saw this thread:

 

You'll see the connection on his first post, though he doesn't indicate how it happened.

 

p.s. "LargeScalePlanes" is a good site to check for information about any 32nd aircraft.  Not my primary scale, so I don't hang out there very much, but might be helpful with some poking around.

Edited by gingerbob

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Thank you for that. The key point that surprised me is that the centre section is horizontal (I had always thought there was a slight anhedral (downward sloping)). Now I have realised it is horizontal it is a relatively easy fix - AT THE WING ROOT. This was the bit that had confused me. I think that I had fallen for an optical illusion.

 

Will

 

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Edited by Scimitar F1
additional sentence

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No dihedral in the center, 5 1/2 degrees on outer panels, per this.

 

Here's a discussion.

 

It appears that getting the fuselage width right is important- not letting the stuff inside force it too wide (or too narrow).  I don't have any of these yet, though I'd very much like a V and II (never cared much about the VI).

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I hadn't seen that thread so thank you for that. The photo confirms the first poster that both upper and lower surfaces should be parallel and horizontal on the inboard section. Nothing a saw and spar will not fix.

 

Will

Edited by Scimitar F1

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Disclaimer: the following is what I believe to be true, that does not make it true. so, correct me if i am mistaken.

 

 The center section of the Tempest is perpendicular to the fuselage when referenced from the leading edge. However, the wing is slightly thicker at the root than where the outer wing panels meet the center section. The reason for this is the airfoil thickness as it relates to the chord length. If I am not mistaken this is the wing aspect thickness to chord ratio. So while it is true that there is no anhedral or dihedral to the center section it can appear that there is because the wing root is thicker.  If you look at the Tempest wing from head on it can be misleading as the open wheel bay will make it look like the bottom of the wing is parallel to the top. I do not have the Special Hobby kit but I have built the Eduard kit.  ok.. you can blast me now if I have messed this up.:door:

Edited by Nachtwulf
I'm an idiot

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Well spotted.  However this is not the Aspect Ratio but the Thickness Chord Ratio.  The Aspect Ratio is the Span divided by the Mean Chord, often expressed as Span squared divided by Wing Area, as these are more often quoted than mean chord.

 

PS.  The chord doesn't reduce a lot between the root and the link, so neither does the thickness.

Edited by Graham Boak

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5 hours ago, Nachtwulf said:

Disclaimer: the following is what I believe to be true, that does not make it true. so, correct me if i am mistaken.

 

 The center section of the Tempest is perpendicular to the fuselage when referenced from the leading edge. However, the wing is slightly thicker at the root than where the outer wing panels meet the center section. The reason for this is the airfoil thickness as it relates to the chord length. If I am not mistaken this is the wing aspect ratio. So while it is true that there is no anhedral or dihedral to the center section it can appear that there is because the wing root is thicker.  If you look at the Tempest wing from head on it can be misleading as the open wheel bay will make it look like the bottom of the wing is parallel to the top. I do not have the Special Hobby kit but I have built the Eduard kit.  ok.. you can blast me now if I have messed this up.:door:

I believe you are correct.

 

To state this another way (and referring to the classic drawings by Arthur Bentley, backed up by those in the excellent “4+” Tempest monograph), it appears that the datum line of the center section airfoil is horizontal, I.e., exactly perpendicular to the fuselage’s vertical datum. Since the wing tapers in thickness, the bottom surface of the center section angles upward slightly, and its top surface angles downward slightly. These effects are difficult to see because the airfoil is relatively thin, however.

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