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YF-16 dimension queries


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Hello guys,

 

I'm currently converting the Tamiya 1/48 F-16C into YF-16 number 2 but I'm a little confused to where and by how much the fuselage was extended between the YF and production versions.

 

YF-1568-Navy-Competition-Paint-Scheme.jp

 

I have this general drawing linked from this zone five YF thread (from the Aerograph I book), and also one in the detail and scale book (I don't have permission to share but is the same, just the entire top view) that is similar. 

 

FSDvYF-16_zpsf3eec4af.jpg

 

 

Then I watched this youtube restoration video of YF-16 number 2. At the 3.25 mark you can see where a 10 inch extension was added to help make this YF-16 the same length of a production F-16 for testing.

 

 

 

Then this vid, a discussion in replacing the nose, in where at 2.07 it is stated the YF nose is 10 inches short than the F-16's nose:

 

 

 

Ok, so those two additions so far make a 20inch lengthening, assuming excluding the pitot, of the YF-16 to match the F-16A. 

 

The William G. Holder F-16 book (1976) gives the YF length as 47.23ft.

 

The Aerograph 1 books gives the F-16A an overall length of 49.49ft, therefore a length difference of 2.26ft = 27.12 inches

 

My questions are:

 

1- The 10" off the nose + 10" fuselage from the 27.12" still leaves a 7.12" difference in length, assuming all these dimensions are accurate. Where is that 7.12" extra coming from?

 

2- From the drawing picture, the cockpit was moved back by 6 inches, where seemingly that made the very tip of the where the LERX meets the forward fuselage in line (side view) with the front of the canopy frame on the YF-16

 

General Dynamics YF-16 at Air Fete 77.

 

Opposed to on the F-16 where the front edge of canopy frame looks about 6+ inches forward of where the LERX starts from the forward fuselage (vertical line).

 

F-16_Nose_and_Cockpit_Side_View_in_Songs

 

 

So was the cockpit moving rearward by 6 inches on top of the fuselage 10 inch plug or incorporated? What I mean is, the whole forward fuselage from the break point in the video (top and bottom) moves back 10 inches but the cockpit area only 4, so in relation to the fuselage reduction, it has appeared to move 6 inches further rear from the F-16? If that makes sense! I'm explaining it like this because that's *I think* how I can replicate it in plastic form on the Tamiya kit, taking the whole front back by 10" but the cockpit line only 4, therefore in relation to the LERX is has only moved 6" back and should be in a vertical line like the YF pic. The reduction in length here, behind the cockpit also explains to me why the YF-16 has much more of a hump look aft of the rear transparency compared to the F-16, roughly the same height change from the forward to reward fuselage seems to be condensed into a shorter length. 

 

 

3- The drawing shows a 11inch rearward move of the intake, but the first youtube video linked states only a 10 inch lower fuselage plug to help bring that YF up to F-16 length for testing, so 10 inch rearward movement. I'm questioning whether the lengthening of the that YF number 2 sensor test airframe, in order to mimic the F-16A, is actually where the real YF was lengthened to the F-16A length. In that is was not as simple on the real deal as that 'quick fix' plug for this YF test airframe. I'm hoping it is! Looking at photos comparing the two, it looks like that is where the fuselage length gain was. 

 

4 - Comparing the Tamiya F-16C NSI front gear well length to the older tool Tamiya and Monogram FSD-ish models, it is noticeably longer. This is also shown by the YF nose gears split doors in these older kits being noticeably shorter than the Tamiya F-16C nose gear bay length (and Hasegawa). I assume this is accurate and the YF nose gear bay was shorter? The rear position of the door and gear well is the same, just that the front of the bay is further back in these FSD kits by a few mm in 1/48, taken into account by the shorter nose gear doors. Which I think would help explain the shorter wheel base of the YF compared to the F-16. 

 

I appreciate none of us have General Dynamics YF-16 drawings at hand but maybe somebody has a clearer idea than I do how the YF was lengthened, I'm a bit confused to be honest! 

 

Thank you in advance for any help,

 

David

 

 

 

 

 

 

Edited by MirageIV
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First of all, starting with the Tamiya F-16C kit is only going to make life harder.  There are much better kits from which to make a YF-16, including the original early Tamiya release #61022: 

 

https://www.scalemates.com/kits/tamiya-61022-general-dynamics-f-16-fighter--133888

 

Second, the prototype and production jets were built up in modular sections, so there is a natural "break" where those sections are joined.  For the YF-16 that break was at FS 253. That corresponds to the bulkhead between the gun bay and the forward fuel tank.  That made for the most logical place to insert "plugs" in YF-16 #2 to match the production profile for the pole test at Rhome.  In the image @dinozavr posted FS 235 is where the "CLEAR LIGHT" callout is, forward of where he shows to cut.

 

So where was the real change made for production? (vs the YF plug mod) Since one of the reasons for the longer airframe was to increase internal fuel storage, and in an effort to not "reinvent the wheel" I'd guess the extension was made at this same manufacturing join point. One way to tell is to compare those FS (Fuselage Station) numbers between prototype and production.  I may have the production FS info in my files but they are in deep storage.

 

You can't use the the LERX to determine cockpit location because the LERX (and nose) is a different shape. In fact those shape differences are some of the big reasons to start with something other than the Tamiya F-16C kit.  Again, the video mentions FS 65 and FS 88 as reference points on the YF, compare those locations to the production FS info to find the differences.

 

Having typed all that, I'd still recommend finding the old Tamiya kit or, better, the Kiddyland kit:

 

https://www.scalemates.com/kits/kiddyland-hf-19-general-dynamics-yf16-ccv--163655

 

See here for more options:

 

http://web.archive.org/web/20080111110036fw_/http://www.habu2.net/vipers/viperkits/48/more48.2.html

 

I'd also recommend perusing this thread, especially the pics on p. 4:

 

 

 

Edited by habu2
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7 hours ago, habu2 said:

First of all, starting with the Tamiya F-16C kit is only going to make life harder.  There are much better kits from which to make a YF-16, including the original early Tamiya release #61022:

...................................................................................................................................

 

 

 

It is not true. If correct, Tamiya's early kit is the F-16FSD (third prototype), which is very different from the first two and corresponds in size to the first production F-16A. The same applies to the Monogram kit

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12 hours ago, dinozavr said:

For the Italeri kit

Backup_of_корректировка чертежа.jpg

P2210277.jpg

20220124_025032-1.jpg

 

Thank you Dinosaur for those images, that is I think where the shortening happened. How did you make the nose? Is it the Otaki/Arii kit nose or modified from a base kit? Your YF-16 looks excellent!

 

Check this video at 3.04

 

 

Kevin Renshaw mentions part of the 10 inch extension was in the extending of the main gear bay 4 inches forward. He had to cut Blk1-30 gear doors down by 4 inches from the front to get them to fit the bay. So that means the 10 inches must have been added to fuselage right at the front of the main gear bay. Also, interestingly he has installed Blk.25 F-16C light weight gear, it fitted perfectly! 

 

8 hours ago, habu2 said:

First of all, starting with the Tamiya F-16C kit is only going to make life harder.  There are much better kits from which to make a YF-16, including the original early Tamiya release #61022: 

 

https://www.scalemates.com/kits/tamiya-61022-general-dynamics-f-16-fighter--133888

 

Second, the prototype and production jets were built up in modular sections, so there is a natural "break" where those sections are joined.  For the YF-16 that break was at FS 253. That corresponds to the bulkhead between the gun bay and the forward fuel tank.  That made for the most logical place to insert "plugs" in YF-16 #2 to match the production profile for the pole test at Rhome.  In the image @dinozavr posted FS 235 is where the "CLEAR LIGHT" callout is, forward of where he shows to cut.

 

So where was the real change made for production? (vs the YF plug mod) Since one of the reasons for the longer airframe was to increase internal fuel storage, and in an effort to not "reinvent the wheel" I'd guess the extension was made at this same manufacturing join point. One way to tell is to compare those FS (Fuselage Station) numbers between prototype and production.  I may have the production FS info in my files but they are in deep storage.

 

You can't use the the LERX to determine cockpit location because the LERX (and nose) is a different shape. In fact those shape differences are some of the big reasons to start with something other than the Tamiya F-16C kit.  Again, the video mentions FS 65 and FS 88 as reference points on the YF, compare those locations to the production FS info to find the differences.

 

Having typed all that, I'd still recommend finding the old Tamiya kit or, better, the Kiddyland kit:

 

https://www.scalemates.com/kits/kiddyland-hf-19-general-dynamics-yf16-ccv--163655

 

See here for more options:

 

http://web.archive.org/web/20080111110036fw_/http://www.habu2.net/vipers/viperkits/48/more48.2.html

 

I'd also recommend perusing this thread, especially the pics on p. 4:

 

 

 

 

 

Thank you Habu for all that information. 

 

What is the 'clear light' callout?

 

I was thinking, using the vid in this post, to make the cut 6 inches ahead of the main Tamiya C bay, then shorten the Tamiya main gear bay by 4 inches respectively, making the correct lower fuselage YF length, then using the same forward vertical cut line as the lower cut, cut 10 inches on the top fuselage. Therefore reducing top and bottom by 10 inches at the same time as incorporating a 4 inch shortening of the main gear bay.

 

A simple pic to understand what I'm thinking, not the best side on pic but I own it to post and demonstrate;

 

L1100056 copy

 

 

Ok understood on the LERX-canopy position. I understand the shape is different and will modify it once I understand where the forward fuselage will be moved, instead of moving a cockpit back, it is way easier to just extend the LERX to meet the vertical line at the front of the canopy and shape it correctly to the leading edge wing root. 

 

I have the Tamiya C, Hasegawa A, Tamiya/Monogram/Esci FSD and still on the the lookout for the Otaki/Arii kit for the nose.

 

The reason I'm using the Tamiya C as a basis is that it is a really accurate F-16, therefore doing the correct backdating mods to it should result in a decent enough YF, it's the best reference to start off with. The Tamiya FSD has some useful parts in it that I will use and modify (fin, tailerons, nose gear bay and doors) but you will be left doing the same basic big changes such as the shortening, wings, tails, nose, LERX etc...as on the Tamiya C, but on a way worse kit kit in terms of details, canopy shape, intake shape etc...might as well put the work into a good modern kit. The bubble canopy of the Tamiya kit is also a big plus for that YF-16 look, none of the earlier FSD kits has that. I now the frame is different but I'll see what I can do.

 

I did start with the Hasegawa A, but because it is already too short by about 10 inches for an F-16, deciding how to chop it up became problematic, everything is already 'out' from the start. At least with the Tamiya C kit you are starting with an accurate F-16 outline to backdate. I've backdated the Tamiya C to Blk 1 before as in the RNoAF F-16A pic above so I have an ok idea how to go about working with the kit to get earlier A variants at least, some of which will be appropriate for the YF. 

 

Also in the vid linked in this post, Kevin talks about the wing reduction. I have 6 inches at the tip, but I don't follow when he talks about the forward flap extension. I thought it was again 6 inches further back on the YF, but he says 10, in front of the seal line.. But that seems to make the wing too small. I've already done the cuts on the Tamiya wing of 3mm of the tips and bring the forward flap back by 3mm, it looks proportionally correct. 

 

Really appreciate your input guys, things are becoming clearer, thank you!

 

David

 

 

 

 

 

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4 hours ago, MirageIV said:

 

Thank you Dinosaur for those images, that is I think where the shortening happened. How did you make the nose? Is it the Otaki/Arii kit nose or modified from a base kit? Your YF-16 looks excellent!

 

 

 

The nose is scratchbuild. The cavities in the nose cone and forward fuselage were filled with resin to obtain the required thickness. Then, with a file, the nose part was given the necessary shape.

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The YF and FSD/production main gear bays are different, with the FSD/prod bays being larger to accommodate the anticipated growth/weight gain capabilities of the FSD over the lighter YF prototype.  Until the recent 1/48 Tamiya and Kinetic kits were released, all other 1/48 kits (including the Hasegawa kit) had main gear bays sized to the YF prototype.  Compare main gear doors on all the kits to see this.  That does not mean the "stretch" was made at the main gear bay, it just means the bay was bigger.

 

While the early Tamiya kit does include some FSD/production changes, the features specific to the YF are still there - specifically the different chine/fuselage interface, gun location and various fuselage ports/vents above the gun. The radome on the early Tamiya (and Monogram/Esci) is somewhere between the YF and the FSD, not correct for either. But, by starting with the latest Tamiya kit or Hasegawa etc. there is the issue of panel lines, which are quite different between YF & FSD.

 

Earlier I mentioned the Kiddyland kit because, even though it appears identical to the early Tamiya/Hobbycraft kits, the fuselage is actually shorter by about 0.2" (~10" in 1/48) so the Kiddyland kit does not have the FSD fuselage extension.  Having said that, the Kiddyland radome is identical to the Tamiya/Hobbycraft, so again wrong for a YF.

 

I still think the best YF can be obtained by starting with either a Kiddyland or early Tamiya kit and grafting on the conical forward tip of the Otaki/ARII kit for the nose profile.

 

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7 hours ago, paulsbrown said:

The Monogram has the split gear doors and some other attributes to the YF.  Sanding the nose area to get the correct shape was not too difficult.

 

Don't forget to removed the arresting (tail) hook, the YFs didn't have one.  :thumbsup:

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On 1/24/2022 at 4:14 PM, dinozavr said:

The nose is scratchbuild. The cavities in the nose cone and forward fuselage were filled with resin to obtain the required thickness. Then, with a file, the nose part was given the necessary shape.

 

Ah ok I understand, nice technique! Do you have photos of the completed model? 

 

On 1/24/2022 at 5:28 PM, habu2 said:

The YF and FSD/production main gear bays are different, with the FSD/prod bays being larger to accommodate the anticipated growth/weight gain capabilities of the FSD over the lighter YF prototype.  Until the recent 1/48 Tamiya and Kinetic kits were released, all other 1/48 kits (including the Hasegawa kit) had main gear bays sized to the YF prototype.  Compare main gear doors on all the kits to see this.  That does not mean the "stretch" was made at the main gear bay, it just means the bay was bigger.

 

While the early Tamiya kit does include some FSD/production changes, the features specific to the YF are still there - specifically the different chine/fuselage interface, gun location and various fuselage ports/vents above the gun. The radome on the early Tamiya (and Monogram/Esci) is somewhere between the YF and the FSD, not correct for either. But, by starting with the latest Tamiya kit or Hasegawa etc. there is the issue of panel lines, which are quite different between YF & FSD.

 

Earlier I mentioned the Kiddyland kit because, even though it appears identical to the early Tamiya/Hobbycraft kits, the fuselage is actually shorter by about 0.2" (~10" in 1/48) so the Kiddyland kit does not have the FSD fuselage extension.  Having said that, the Kiddyland radome is identical to the Tamiya/Hobbycraft, so again wrong for a YF.

 

I still think the best YF can be obtained by starting with either a Kiddyland or early Tamiya kit and grafting on the conical forward tip of the Otaki/ARII kit for the nose profile.

 

 

Thanks Habu for the further info!

 

Ok, got you on the main gear bay. It was one of the reasons I did, then didn't start with the Hasegawa kit. Whilst it has the shortened bay, it's 10 inch length deficiency throughout the fuselage was making it difficult to determine where to make another shortening to make a proportional YF, you would just make a short kit even shorter, so a YF in proportion to the Hasegawa kit but not reality, I dunno, I found it difficult to determine where to chop. I will use the Tamiya FSD kit gear doors and use them to dictate the modified C main gear bay length. Pretty sure I can make it work after some testing. 

 

Looking at it again, I agree that the stretch is not into the bay, I think it probably is in the same position it was for the Rhome test. What do you think, should I shorten the length there? I still don't definitively understand where it is. To my eyes, if I cut aft the same point they did for the Rhome pole model and remove 10 scale inches rearwards top+bottom, it will give the YF's characteristic sharper height transition from the aft transparency to the middle upper fuselage. and bring the intake back in unison to where it should be in relation to the canopy from a side profile view. It just *looks* like that is where the extra length was given to the YF for the F-16 imho.

 

I understand your logic for recommending the Tamiya/shorter Kiddyland FSD kits and agree with it in general. It's just that some particular shape things that are important to me stopped me and some physical modelling construction things. I just don't like the canopy, it's too long with a weird tint, if I replaced it with a Hase/Tam C canopy I'd have to cut and chop that area of the fuselage and build up the canopy base which I'd find quite difficult tbh to get it all right and level. The intake, whilst NSI mouth profile is ok, does not go deep enough vertically to my eyes, it looks kinda squished in comparison to the Tam C NSI intake, which apparently was unchanged from YF to F-16. I'd prefer to have engraved panels so I'd have to rescribe the whole thing and because I'd have to chop it up anyways to get the YF wing/fuselage/taileron dimensions, it just didn't add up for the end model I have in my mind. I know there are many mods needed on the Tamiya C kit to YF conversion  (I won't get them all, it will be a best effort YF, like any 'YF' kit in 1/48 tbh), but each one is easier than trying to replace the canopy and scribing on the Tamiya FSD for me. I hope you understand more where I'm coming from. I've already done the wing cutting and A tail fuselage graft to the Tamiya kit now, so no going back! 

 

 

13 hours ago, paulsbrown said:

The Monogram has the split gear doors and some other attributes to the YF.  Sanding the nose area to get the correct shape was not too difficult.

 

 

 

Hi Paul, I've seen your wonderful build over on BM and it was actually one of the reasons I started this project, it looks excellent! I got the Monogram kit as a nose back up incase I can't find an Otaki/Arii kit, it has a more YF profile obb than the other FSD kits and as you show, with some modification it can look great. 

 

Thanks guys fo the input!

Edited by MirageIV
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20 hours ago, MirageIV said:

I got the Monogram kit as a nose back up incase I can't find an Otaki/Arii kit,


given the rarity of Otaki/Arii kits, I wonder how close the radome  off an F-5A or E kit might work?  Unfortunately I don’t have one to compare right now…

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  • 2 weeks later...
On 1/26/2022 at 2:46 PM, dinozavr said:

Unfortunately, the model is still in progress. Upon completion final photos will be taken

 

 

Ok cool! Would love to see it when completed.

 

On 1/26/2022 at 5:25 PM, habu2 said:


given the rarity of Otaki/Arii kits, I wonder how close the radome  off an F-5A or E kit might work?  Unfortunately I don’t have one to compare right now…

 

My initial plan was using a combo of the Monogram FSD nose and Esci F-5 needle nose, tricky work, but fortunately I have managed to track down an Arii kit which makes things much more simple. The Arii kit really captures the forward fuselage and LERX well, after trying to modify the Hasegawa forward fuselage I realised there is a lot more too it, the whole YF-16 forward fuselage is different to the F-16 in many ways and only the Arii kit actually gets it right imho.

 

After doing a lot of cutting and photo comparison, I think I've got a pretty good frankenstein YF-16 on the go using the Hasegawa as a base (cut down appropriately) but with the whole Arii front end added to it and a spare Tamiya C NSI intake with Tamiya FSD nose gear bay. I will show some photos of what cuts Ive done if interested. A lot of work!

 

Thanks guys

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  • 5 months later...
On 1/23/2022 at 9:57 PM, MirageIV said:

 

YF-1568-Navy-Competition-Paint-Scheme.jp

David

Hey David,

 

How is your project coming along?

 

I want to ask you about the ejection seat. In the first photo you posted it seems that the seat is an escapac IG-2. Is this correct or did they use another type of seat?

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  • 6 months later...

From Kevin Renshaw,

"

Jim Hodgson passed along your message regarding questions about differences between YF-16 and the early model production F-16.  I tried to document the differences in the attached set of charts.  YF-16 #2 was seen as a "pre-production" airplane rather than a prototype and it formed the basis for the production design.  Note that only #2 had a gun and fully operational weapons capability.  #1 was purely an aerodynamic and handling qualities bird.

 

I also included some photos and notes from after we stripped the paint; I know model builders love to see panel lines and details.  We are getting ready to repaint the bird back into the May 1975 red, white and blue scheme.  That date represents how it looked when Neil Anderson landed this aircraft with the landing gear stuck.

 

regards

 

Kevin Renshaw

 

 

253943763_YF-16vsF-16Changes.pdf

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Forum software does not allow file attachments other than image files smaller than 100 Kb.  You'll need to upload your pdf to a site like Dropbox and then provide a link to it here. 

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A couple things to note that didn’t make it into the PDF. The strakes were not extended with the forward fuselage and on the YF along with the mating being more prominent, they reach all the way to the cockpit bulkhead FS 98.0. The starting point of the YF nose (no Pitot) is FS 8.0 while the production is FS -5.0 (this PDF shows FS -2.0 but that is wrong as the actual line drawing found in Aerograph 1 is a production drawing) meaning the nose moved 13” forward while the forward fuselage was only extended 10”, indicating the nose was lengthened 3”.

 

https://www.dropbox.com/s/6lbndyo8h5wtilm/YF-16 vs F-16 Changes.pdf?dl=0

Edited by Vikingson
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