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1/72 - Yakovlev Yak-1 & Yak-1b by Brengun - Yak-1 & Yak-1b released - new Yak-1b boxing


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Oh okay. Boy oh boy do i know when i smell a kitbashing in the making 😄  Those big recesses on the lower wings of the Brengun kits near to the undercarriage bays, the Arma kit does not have this as a recess, it`s flush with the surface. Brengun have any parts to make that area flush and what is it?  

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12 hours ago, top turret toddler said:

Oh okay. Boy oh boy do i know when i smell a kitbashing in the making 😄  Those big recesses on the lower wings of the Brengun kits near to the undercarriage bays, the Arma kit does not have this as a recess, it`s flush with the surface. Brengun have any parts to make that area flush and what is it?  

 

Are you sure you're talking about the Brengun Yak-1B kit and not the Yak-1? The recesses in the Yak-1 kit wing are the fuel tank locations; the Yak-1 kit has photoetch to complete these and bring them flush with the rest of the wing undersides. The Brengun Yak-1B has the covers shown by panel lines molded in the plastic, as would be usual with most other kits - entirely different from the Brengun Yak-1.

 

John

Edited by John Thompson
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On 12/21/2019 at 11:10 PM, AaCee26 said:

.... For me wing planform accuracy is the main reason to go to the Brengun kit. Arma doesn't look right and after checking it with an original factory document I'm confident about this....

 

The wing "posted" here  - https://www.pwm.org.pl/viewtopic.php?f=14&t=88798

look more like Arma Hobby one, or am I wrong?

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5 hours ago, Wojtek2 said:

The wing "posted" here  - https://www.pwm.org.pl/viewtopic.php?f=14&t=88798

look more like Arma Hobby one, or am I wrong?

Hi, I am not sure what you meant in the message, but having another look at Kuznetsov's drawings (which are consented  to be rather OK in the planform and more or less are in line with the published measuring), I still tend to think that Arma's wingtips are too narrow and thus look too "pointy". It is rather obvious if you have a look at the photos of the wings of any Yak-1. Not exact as they are one can more or less have and idea of a shape.

The color picture from the thread you suggested is taken from the Yak-1 manual and was intended for illustration purposes only.  You would have similar  questions and issues comparing things to pictures in comic books, or trying to replicate the Soviet camo by the illustrations from 1941 "Instruction on camouflage".

I have the measurings published at scalemodels.ru and, if I have time, shall try and measure the Arma kit. "If I have time, or do not forget"(c)

Happy New Year!

 

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This is the Arma Hobby wing 3D design (colour lines) compared with the Yakovlev. Yak 1 vol. I i II
Sergei Kouznetsov, Alexander Rusetski Kagero book plans (black lines).

Please note that the Yak-1 had different position lights than Yak-1b.
 

 

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Edited by GrzeM
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Hi Grze,

 

Looks like Arma CAD follows exactly the Kagero drawing. But when compared to the period drawing the trailing edge starts to curve from third rib counted from the aileron tip, or from outer aileron hinge point. 780 mm from wing tip which is a hair less than 11mm from the wing tip.  Kit aileron starts to taper earlier and also the wing leading edge shares this feature.

 

Happy New Year!

 

Greetings,

 

AaCee

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You mean this picture (from airplane manual)?
spacer.png

 

Here is good comparison of Yak-1 and Yak-9. You can also see how far from the wingtip the straight trailing edge starts to bow.
spacer.png

Edited by GrzeM
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This becomes more and more interesting....I have dug out the kits to compare and here are some findings (relatively crude for now) :

I compared the wings of Arma to BrenGun (after it was cleaned up from flash - sadly despite being a new kit BrenGun one still shows some) and as expected found the difference in the wing tip. It is a relief, as I started thinking, I am losing the sense of shapes after looking at the similar images for a while.

The wings actually show very good correspondence up until the point of outer wing aileron"border" and depending upon positioning a relatively similar shape along the leading edge up to the point of the position light. The trailing edge outside is were the difference is and Arma is about 1-1.3mm thinner were nervure (rib) 22 is supposed to be, hence a more pouty look of the wing tip.

Now what is correct? I am not sure now. I could not find the exact dimensions of nervures 22 and 23 anywhere and the only two sources available to me are the ones from Luranc's set (and Kuznetsov's drawings are reputedly based on them) and the German drawings taken from a captured Yak-1 in 1942. Neither of them provides the measurements for these particular parts, but sort of scaling off the copy of both (so please, mind these are far from perfect) gave me that according to Luranc #22 should be 720mm and according an unknown German circa 1942 -735mm. Now we know for sure, that the base of Luranc measurements were not perfect and rather crude, but they are still the best available. The German drawings, being done professionally and giving some extra details is also questionable (for example it omits #23 completely). 

I measured the wing of Arma's kit were the nervure 22 should be (I have drawn the ribs by pencil to be more precise) and arrived at 645mm (scaled up) or 8.96mm on the model.

Now, I would assume that this discrepancy is accountable for the "pointy" look of the wing compared to BrenGun. And everything now boils down to the accuracy of the source drawings if Lurancs drawings are good (and my calcs are correct) there is a small problem with Arma's Yak-1 wingtip. To my eye and on the sprue Arma's wings looked strange. But I might be just overthinking it, and frankly after removing both Arma's and BrenGun wings from the sprue and putting them side by side, perhaps the difference will not be noticeable? If Arma's source is better, than Brengun's kit needs fixing - and this would take no time at all- just a few careful strokes by a needle file. 

 

And to muddy the waters further- I crudely measured the elevator on the Arma's stabilizers and it is spot on in accordance with the published dimensions, But the stub for stabilizers positioning on the fuselage is oversized.... So more attention and digging is needed here, and perhaps BrenGun dropped the ball here.

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17 hours ago, GrzeM said:

You mean this picture (from airplane manual)?
spacer.png

 

This and the one in msg #75. Both shows thet the trailing edge starts to curve towards tip from the hinge rib. The other drawing gives the measurements I had in my previous message. Kagero and Arm,a starts to curve earlier.

 

17 hours ago, GrzeM said:

Here is good comparison of Yak-1 and Yak-9. You can also see how far from the wingtip the straight trailing edge starts to bow.
spacer.png

Left or right wing? ;) Compare the arch of the curve between photos and Kagero drawing/Arma model.

 

I have browsed so far a dozen books of wooden-wing Yak-1/7/9 trying to find a photo showing the wing shape properly. So far I haven't found a spot-on one but what I have found supports in my opinion my opinion :)

 

Cheers,

 

AaCee

 

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5 hours ago, AaCee26 said:

This and the one in msg #75. Both shows thet the trailing edge starts to curve towards tip from the hinge rib. The other drawing gives the measurements I had in my previous message. Kagero and Arm,a starts to curve earlier.

Could you show it in some way? In my opinion Kuznetsov drawing (from Kagero book), precise and measured, looks the same as the colour drawing from the Yak manual. Your little drawing from #75 post is to small to determine anything and shows the Yak-7, not the Yak-1b. Even Yak-1 wingtip was different than Yak-1b one.

 

5 hours ago, AaCee26 said:

Left or right wing? ;)

Left wing (one of the top). Right wing is more affected by the perspective - the wingtip is hidden.

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5 hours ago, AaCee26 said:

I have browsed so far a dozen books of wooden-wing Yak-1/7/9 trying to find a photo showing the wing shape properly. So far I haven't found a spot-on one but what I have found supports in my opinion my opinion :)

Arma Hobby kit is Yak-1b, not Yak-1, not Yak 7 and not Yak-9.

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25 minutes ago, GrzeM said:

Could you show it in some way? In my opinion Kuznetsov drawing (from Kagero book), precise and measured, looks the same as the colour drawing from the Yak manual. Your little drawing from #75 post is to small to determine anything and shows the Yak-7, not the Yak-1b. Even Yak-1 wingtip was different than Yak-1b one.

 

Left wing (one of the top). Right wing is more affected by the perspective - the wingtip is hidden.

Please count the ribs on the manual drawing from aileron tip to the hinge. Hinge is in 3th rib counted from aileron outer edge.  Aileron trailing edge starts to curve from this point.

 

Kagero drawing starts to curve earlier. The manual drawing is a primary source, Kagero is a secondary one.  A good  one, but still not an original document.

 

Yak-family wooden wings were all derivated from the Yak-1 wing. There were lot of differences between types with many details, lights, fuel thanks, landing gear, tip shape etc. but the main geometry is the relevant one in this case. If I have understood correct the basic geometry between them was the same.

 

Try this for the Yak-7 wing (and a German "Jak-1" wing drawn 1942) drawing : http://massimotessitori.altervista.org/sovietwarplanes/board/index.php?topic=2455.msg22065#msg22065

 

This is my opinion and I have told why I think so. Everyone has freedom to agree or disagree with it.

 

The kit is a very beautiful one. I would be happy to be proofed to be wrong ;)

 

Cheers,

 

AaCee

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19 hours ago, AaCee26 said:

his and the one in msg #75. Both shows thet the trailing edge starts to curve towards tip from the hinge rib. The other drawing gives the measurements I had in my previous message. Kagero and Arm,a starts to curve earlier.

Sorry, but no. I actually referred to this drawing in my message as the "comic book one". My calcs were based on Luranc drawings (which are reportedly  the base for all Kuznetsov's books drawings) and the German drawing AaCee refers above. Unlike, AaCee, I would not pay too much heed to the manual picture, it is a good and solid reference source, but not really a guide to shapes and sizes, in my opinion.

 

I am happy to admit that Arma's CAD model is based in the Kuznetsov plans and the fact that on their screens it corresponds to them perfectly, but looking at the result in plastic, it does not seem so in the wing tip area.

 

And finally, I am totally with AaCee here  - I would be very happy to see my calcs about nervure 22 and 23 wrong as it is much easier to bring BrenGun Yak-3 to Arma's shape, and I have an fully intend to build both of the kits.  

 

 

 

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6 hours ago, BallsBuster said:

I am happy to admit that Arma's CAD model is based in the Kuznetsov plans and the fact that on their screens it corresponds to them perfectly, but looking at the result in plastic, it does not seem so in the wing tip area.

This is Arma plastic on the Kuznetsov plans from the Kagero Kuznetsov book.

 

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For what it's worth, several months ago I had a brief correspondence with Wojtek regarding the goodness of the Luranc drawings. He said that they had begun the Yak-1B design process with the Luranc ones, but then progressed to the Kuznetsov drawings. I must have deleted the discussion; that was what he said, as clearly as I can remember it.

 

John

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Well, I browsed again the Kakero books and looked especially pictures on page 33 top (Yak-1b) and 99-100 (Yak-1 tall back resttoration project). The wing tip curve radius is much tighter in both trailing and leading edges than in the drawings of the book.

 

Looks like BallsBuster and I have come to same conclusion with different methods. I see the period material value in the way how they deptict structures as they were made by people who were working with the real planes.

 

Cheers,

 

AaCee

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Quote

Kagero drawing starts to curve earlier. The manual drawing is a primary source, Kagero is a secondary one.  A good  one, but still not an original document.

 

Yak-family wooden wings were all derivated from the Yak-1 wing. There were lot of differences between types with many details, lights, fuel thanks, landing gear, tip shape etc. but the main geometry is the relevant one in this case. If I have understood correct the basic geometry between them was the same.

 

Try this for the Yak-7 wing (and a German "Jak-1" wing drawn 1942) drawing : http://massimotessitori.altervista.org/sovietwarplanes/board/index.php?topic=2455.msg22065#msg22065

Comparing these two drawings it is obvious that the area we discuss (curve on the aileron) differs a lot on these two drawings (German Yak-1 and Yak-7). How do you explain that? Which one is correct? Or maybe both are somewhat wrong?

"Primary sources" - at least German drawing is measured. The colour drawing from the period airplane manual shows the structure, but definitely is not the measured plan and can not be considered as a source of information about shapes and sizes.

 

I suppose that the "problem" with the Arma Hobby Yak-1b wing comes from optical illusion caused by the fine and thin, sharp edges of the kit parts - which may optically appear as more narrow than they really are - and the wingtip light which mekes it even more pointed.

Edited by GrzeM
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This will probably only demonstrate how low my approval threshold is, but, ummm, I managed to reshape the Arma wingtips to about a 90%-accurate match of the outline on the Luranc drawings, with just the proverbial "few strokes of a sanding stick". From even a short distance, it looks pretty good, if I do say so myself.

 

John

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On 02/01/2020 at 23:08, AaCee26 said:

Please count the ribs on the manual drawing from aileron tip to the hinge. Hinge is in 3th rib counted from aileron outer edge.  Aileron trailing edge starts to curve from this point.

 

Kagero drawing starts to curve earlier. The manual drawing is a primary source, Kagero is a secondary one.  A good  one, but still not an original document.

 

Yak-family wooden wings were all derivated from the Yak-1 wing. There were lot of differences between types with many details, lights, fuel thanks, landing gear, tip shape etc. but the main geometry is the relevant one in this case. If I have understood correct the basic geometry between them was the same.

AaCee,

Your assumptions are all correct. But, shouldn't that be discussed in an separate thread? This is about Brengun. I mean, subject may be confusing.

 

First, facts and my own comments. Speaking only on wings (so far):

- yes, all Yak-1/3/7/9 family is evolved from yak-1. Yak-3 aside, it is smaller, redesigned version of the wing. Yak-9 had redesigned wing tip with straight trailing edge almost to the end of wing, so again aside.

Yak-1, Yak-1b and Yak-7 had the same outline, differing on the wheel wells/landing gears, fuel tanks and flaps.

Especially Yak-1 and Yak-1b had the same outline and there is no reason to guess it. I am very surprised Arma Hobby crew (here, represented by Grzegorz) does not know that.

- there is Yak-1 factory drawing published in at least few books, two main are:

Eksmo (2009) - Yakowlew Yak-1 [Як-1. Наш лучший истребитель 1941 года] (by Sergei Kouznetsov)

Kagero (2017) - Yakovlev Yak-1 Vol. I & II (by Sergei Kouznetsov and Alexander Rusetski)

as you see, Arma Hobby has factory drawing in the book they used.

Kagero monograph vol. I treats on Yak-1 and does not contain Rusetski drawings, so vol. II is on focus. However, factory plan can be found in the vol.I of the book.

- drawings from the Kagero Book are drawn by Alexander Rusetski, not Sergei Kouznetsov. Both are co-authors of that (excellent!) monograph, however.

- drawings are very detailed and really well researched, but does contain small errors. One of them is a wing tip shape.

Pictures speaking itself. They are posted on imgur/clickable.

 

Kagero structure plan (red) on the factory structure plan (blue)

efs5zVvl.jpg

 

Kagero Ouline plan (green) on the factory structure plan (blue)

WAvEe1Al.jpg

 

Speaking about Arma Hobby Jak-1b you should divide issues to at least two :)

- if the kit shape is compatible with a book drawing (it is almost perfect)

- if a book drawing is compatible with factory drawing (it is not)

 

AH wing with Kagero plan (red) - is lays very good

plkLbvTl.jpg

 

AH wing with factory plan (you judge)

Tc43nD7l.jpg

 

All my opinion is subjective of course - I am writing it because Arma Hobby crew is oversensitive on any criticism of their job. This is not my intention, I am trying to help you understand that subject.

I believe we could discuss on the other issues of the kit, but I strongly feel this is not a right place.

 

 

Edited by HKR
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4 hours ago, HKR said:

First, facts and my own comments. Speaking only on wings (so far):

[...]

- [Kouznetsov/Rusetski book] drawings are very detailed and really well researched, but does contain small errors. One of them is a wing tip shape.

For the discussion purpose it would be nice if you point which ones are really 'facts' and which ones are your comments (or opinions). We may discuss the facts, while your opinions remain your opinions (or comments).

Especially your opinion about the accuracy of the Kouznetsov/Rusetski book drawings (unless you prove it some way).

Quote

Kagero structure plan (red) on the factory structure plan (blue)

efs5zVvl.jpg

 

Kagero Ouline plan (green) on the factory structure plan (blue)

WAvEe1Al.jpg

Very interesting. As you noted, the OKB (Yakovlev design office) drawing is "structure plan" - it shows the wing structure and some measurements, while it is obvious that such drawings not always give correct shapes. It is clearly seen in the wing front view (with several 'kinks') and also in the wing trailing edge - which is shown there not as a straight line but with some 'kinks' (look at the area between undercarriage leg root line and the fuselage).
It is also very interesting that this OKB plan - if it is correct in outlines - proves that AaCee is wrong speaking about the aileron trailing edge curve starting point.

 

Another very interesting thin is that another 'factory drawing' (of Yak-7 - already posted here - showing 'outline identical as Yak-1') is very different speaking about the aileron trailing edge shape. In my opinon these OKB or factory drawings does not show the proper outlines, because their purpose is different - to show the structure and measurments.

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Quote

Speaking about Arma Hobby Jak-1b you should divide issues to at least two :)

- if the kit shape is compatible with a book drawing (it is almost perfect)

- if a book drawing is compatible with factory drawing (it is not)

I think the most important issue here is the third one - which one is more compatible with the real airplane.

Quote

AH wing with Kagero plan (red) - is lays very good

plkLbvTl.jpg

 

 

This is very important information. Arma Hobby kit outlines agree very well with precisely drawn and measured plans from the book prepared by probably the world best Yak airplane specialists Kouznetsov/Rusecki (and probably based on the most actual research).

Quote

Arma Hobby crew is oversensitive on any criticism of their job.

Marku, this is Britmodeller Forum. I don't think such judgements about someone's personality are needed here.

Edited by GrzeM
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Gentlemen,

 

Every drawing should be taken with a grain of salt. Every.

 

In this case please compare the wing tip of different drawings with a photo of the Yak-1b wing in the Kagero Yak-book vol 2 page 33, top. Look the curvature of the wing tip outboard the aileron on both trailing and leading edges to the photo. Another useful photos are in the same book page 99 of a recovered wreck of a high-back Yak-1 and in page 100 of a rebuilt wing for the same plane.

 

Make your own conclusions. I have done mine. This is likely my last words about this subject.

 

Cheers,

 

AaCee

 

PS. Moderatos: Would you please split this part of this chain to separate discussion in appropriate location.

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As I find some people becoming ridiculous in their crusade against Arma whatever the latter does (and before I go further, I would like to note one more aspect: Arma is now being criticized for strictly following the drawings that are considered the most accurate. I'm pretty sure that if they didn't follow them, the jihad would be twice more intensive :) ), I decided to ask the original source. This is what Sergey Kuznetsov answered:
"Neither of the factory drawings used (in this thread) are a scan from the original drawings (these are polygraphic and photo copies), which therefore may result in various distortions in the first place, and in particular, the shapes. Before the publication of the drawings in the English edition of Kagero, naturally, more than one wingtip drawing went through my hands. Based on the materials and sizes found, Sasha Rusetskiy built a 3D model of the Yak-1 (for linking problem areas in my drawings from 1995, which have become known over the past time, and of which the modelers themselves told), and then this was used to make 2D drawings at different scales. Therefore, the drawings of 2016 turned out to be as precise as possible, finalized and close to the original. To avoid any disputes about distortion in 2D drawings, dimensioned drawings were specially provided separately from them. Using these, everyone can optionally build their own exact model of the machine.
The process has not ended, new documents are found and drawings are being updated on their basis.
Discussions about the "millimeter" and "shades of green" amongst the modellers will never end. They would have seen an agreement with the Air Force, which gives tolerances of 0.2% for all linear dimensions of the machine. In other words, the wing span of the serial Yak-1 could be 10020 and 9980 (139.2 and 138.6, respectively, in 1:72 scale). However, I am glad that our drawings have already begun to be compared not with the drawings of Luranc, but with the original, as it should be ;)"

Edited by caughtinthemiddle
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