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Sea Vixen boom length


Pat C

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I asked my long suffering Dad to measure the length of the tail booms of Yeovilton's Sea Vixen given the issues around the accuracy of several kits in this respect.

He measured 3530mm from the wing root to the forward edge of the rudder. I scaled that to about 5cm in 72nd. I have the High Planes kit and that looks to be pretty much spot on. If you saw my build of the Cyber-Hobby kit you know I chopped part of the boom off and in fact it is still several mm too long. Perhaps someone could measure a non-chopped kit and post the results here?

Would anyone be able to measure the booms on the Xtrakit/ MPM, Frog and Airfix 1/48 kits and also post the results here for reference?

Pat

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I am away from home and can't get to my stash but am delighted that you've initiated this research. i have the Hi-Planes and Frog in the stash.

Please thank your Dad for his service to modelling!

David

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A bit hard to measure as both kits are unassembled and the front edge of the rudder is shaped slightly differently on each but I make the Frog one 5.5cm and the Hi-Planes one 5.1cm.

David

Edited by David Womby
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Thanks chaps - anyone got a Cyber-Hobby or Airfix 48th they could measure?

Length of the aircraft is often quoted as 55' 7" and yet the pilots notes quote 53' 6 1/2". I understand the later to be the accurate one - about 8mm different in 72nd. Interesting that the Xtrakit is 6-7mm longer in the boom than High Planes and I reckon Cyber-Hobby will be also around this amount longer if not more.

Pat

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Pat

This thread prompted a buried memory that sent me hunting through my enormous stack of magazines.

I found an article by a Mike Chaplin in an old SAMI Oct1999 (v5 issue10) saying the Frog one needs its booms EXTENDING by 4mm!

So I just want to confirm I measured the right thing - from the trailing edge of the wing to the frontmost point of the rudder (not the fin).

David

Edited by David Womby
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David - you have measured it right. If the writer of the article was working from 55' 7" as the length (and I understand there are plans that show this) then an extra ~4mm would be what you might think was needed. Just by eyeballing pics and looking at where the NACA duct and "Royal Navy" titles sit relative to each other and the wing root I was was fairly convinced that High Planes are right and Cyber-Hobby are way off - Frog would be somewhere in between from your measurments.

There was a Russian chap on here who posted some photos overlaying the dodgy plans on a photo that showed the issue - I'll try and find it.

EDIT - found it see below

http://postimage.org/image/qcky0xfy7/

Pat

Edited by Pat C
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>

There was a Russian chap on here who posted some photos overlaying the dodgy plans on a photo that showed the issue - I'll try and find it.

>

Pat

Wow - great underside shot of the real thing. So the red are the spurious plans. Interesting.

David

I don't know if this helps at all? It's from the Sea Vixen illustrated parts catalog, so I assume it's quite accurate

John

Great. Thanks.

David

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Interesting stuff this.

I've long wanted to do a D.3 and have the Revell/Frog release along with all the Aeroclub

bits for it.

I heard(on here or Unnoficial Airfix Forum)that the Froggie needs 3mm in the booms

along with 2mm in the radome to bring it up to length.

A quick scale convertion gives us 226.66mm OAL in 1/72nd for PN's quoted 53' 6 1/2".

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I heard(on here or Unnoficial Airfix Forum)that the Froggie needs 3mm in the booms

along with 2mm in the radome to bring it up to length.

Miggers - I think the fix for the Frog radome is more for aesthetic rather than than accuracy reasons. The fuselage is supposed to be too fat and the radome stretch gives a better overall "impression". Assuming we are all measuring from the same datum, there appears to be evidence to suggest the Frog boom is not too short but possibly the opposite. See pic below to help!

Pat

Vix1-1.jpg

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Yes Pat,apparently it is too wide on the fuse. itself but the span works out right.

You can see it looking at the underside,the position of the pylons and the fact that the

missiles won't fit on without fouling each other.

I believe you're correct about the 2mm radome fix,sanding down the RATOG bulges

either side of the nosewheel well is also said to help,it's reckoned they're too big.

139" works out to 49.04mm in 1/72nd,so that makes the Frog at 55mm and the

Highplanes at 51mm both too long in the booms!!!!

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Miggers - I think the fix for the Frog radome is more for aesthetic rather than than accuracy reasons. The fuselage is supposed to be too fat and the radome stretch gives a better overall "impression". Assuming we are all measuring from the same datum, there appears to be evidence to suggest the Frog boom is not too short but possibly the opposite. See pic below to help!

Pat

Vix1-1.jpg

Airfix 6.9 cm with 1/48/rule 10' 9" Cyber Hobby 5.7 cm with 1/72 rule 13' 6" Edited by Grizzly
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The drawings that I have are for the FAW.2, and they seem to match the 55' 7" overall length which is quoted in numerous sources (for the FAW.2). The picture above from the parts manual is for a FAW.1, and lists the overall length as 53' 6.5". Does anyone know if there really was a difference between the two marks? Longer radome, longer booms, etc. Something that may account for the difference, assuming both values are "right."

I'm starting the Xtrakit model, and I don't want to be cutting away any more than I have to on the booms! Is it possible that the addition of the extra fuel tanks, which extended the boom past the front edge of the wing, also necessitated extending the booms on the rear for balance, or to keep the same center of gravity and thereby maintaining the flight characteristics of the plane?

Cheers,

Bill

Edited by Navy Bird
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I've considered chopping the Frog fuselage to bring it back to the correct width before, but it's not going to be an easy job I fear.

Now I wonder if using the measurements shown in the document posted by John it would be possible to correct the existing drawings ?

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The drawings that I have are for the FAW.2, and they seem to match the 55' 7" overall length which is quoted in numerous sources (for the FAW.2). The picture above from the parts manual is for a FAW.1, and lists the overall length as 53' 6.5". Does anyone know if there really was a difference between the two marks? Longer radome, longer booms, etc. Something that may account for the difference, assuming both values are "right."

I've been thinking about that too, if the IPC and pilots notes say the same would it be safe to assume the length for both Mk's is 53'6.5", in the IPC it gives the length of the radome (with masking strip) as 6'9" how dose that compare to the Mk.2?

This is the text from radome to tail plane, what do you think? are the two Mk's the same length? is it the way the parts are dived up? or is this just the case that a wrong measurement has become accepted as fact?

Vix3_zpsc38ca382.png

John

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I did some more fooling around with this last night. If I take my Sea Vixen drawings (either the one on Wikipedia or from Blueprints.com) and scale the length of the aircraft to be 55' 7" (at 1:72 scale) then the forward portions of the Xtrakit (main fuselage section and radome) are a "reasonably" good fit, the one noticeable error is that the two openings for the pilot and navigator are off by a few millimeters. Looking at the booms, they seem to be about 5mm too long, which is pretty close to what has been stated previously.

If I scale the drawing so the length of the aircraft is 53' 6.5", the Xtrakit is oversize everywhere. Nothing matches, so it seems obvious that Xtrakit (MPM) used the 55' 7" value when engineering their kit.

Another thought that came to mind was the idea that 55' is the actual length along the aircraft centerline, and 53' is the length along the ground. I did the math, and this would require the aircraft sit at a 15 degree angle, nose high. Looking at a lot of photos, she certainly sits nose high, but it doesn't look anywhere near a 15 degree angle. So I don't think that's the confusion.

It will be interesting to hear what else can be determined. For my building of the Xtrakit FAW.2, I will go with the drawings scaled to the 55' figure, since that is obviously what they used. I will shorten the booms accordingly. If the actual figure is 53', then the Xtrakit model is about 3% too large, probably not noticeable with Eyeball Mk.1.

Cheers,

Bill

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I've been thinking about that too, if the IPC and pilots notes say the same would it be safe to assume the length for both Mk's is 53'6.5", in the IPC it gives the length of the radome (with masking strip) as 6'9" how dose that compare to the Mk.2?

This is the text from radome to tail plane, what do you think? are the two Mk's the same length? is it the way the parts are dived up? or is this just the case that a wrong measurement has become accepted as fact?

All descriptions I've read of the FAW.Mk.2 conversion say that the booms were extended forwards, ie ahead of the leading edge - nothing about any substantive additional structure aft of the trailing edge. I suppose the radome might have been longer, but with the same equipment inside it I can't think of a reason to extend it; and besides, two feet of difference ought to be obvious even to the naked eye, with that short fuselage. I have the old Birtles and Gunston books at home and can double-check later, but my money's on an error being handed down.

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