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Outdoor Free Flight Forum => Free Flight Scale => Topic started by: atesus on October 30, 2013, 01:59:19 AM



Title: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on October 30, 2013, 01:59:19 AM
I started building the Kocherigin & Gurevich TSh-3/TsKB-4 WWII Russian ground attach aircraft from Michael J. Heinrich plans, enlarged by 150% to 24" wingspan.

The information I was able to gather on the original is quite sketchy at the moment. I hope to find more and reliable information on the plane as I go on with the build. What I know so far is that the design was geared towards the Russian air force requirements of 1932 for a heavy armored ground attack monoplane with a top speed of 250km/h, an operational ceiling of 4000m and strong armament. The design work was done by S.A. Kocherigin and M. I. Gurevich. The airplane was basically a steel tub all the way back to the rear gunner, and a duralimin frame covered with fabric aft of that. The wings also had a duralumin frame covered with fabric. The aircraft had a radiator retractable during strafing runs and the cooling was temporarily provided by air sucked in through an armored scoop and plus 106 lt of water in the cooling system. Apparently two prototypes were built. The aircraft was first flown in 1932 and met the design targets comfortably. However by the time the trials and refinements were complete in Spring 1934, the aircraft was already obsolete in 1934 due to fast progress in aircraft designs in that time frame. The aircraft never went into mass production.

With it's ample wing area, this model has the potential of being a good performer. I hope I can do justice to her :D.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on October 30, 2013, 02:10:22 AM
I was able to find one photo, a few illustrations and a very rough 3-view for the aircraft. Between those, there are quite a few discrepancies. I'm intending to rely mostly on the only photograph I have. Since there's no hard core scale competitions in my neighborhood, I'll probably take quite a few liberties too. I started a thread on SFA where I titled the thread "a what-if project" which pretty much sums up how I approach this model.

Here are the only photo I have, followed by a couple illustrations, a render from an online game and the rough 3-view.

Not sure if the plan is available in the HPA plan gallery but I know it's available at Outerzone. If they are not available here, I'll upload them.  

EDIT: The plan is available under the "Death Trap Squadron plans" in the gallery.


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 03, 2013, 02:31:32 AM
Nothing earth shattering so far but some progress nevertheless :).

Built the fuselage sides on top of each other and started putting the fuse together.

The 3/32" sq running in the center of the front section of the fuselage is not on the plan. I'm planning to sheet the areas which are armored in the original and I'll need that extra structure for gluing the 1/32" sheeting pieces.

The double vertical members towards the rear of the fuselage are in support of my intended DT scheme (I'm planning to tip up the whole tail). 


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 14, 2013, 03:27:07 AM
I got a chance to do some more work on the TSh-3.

The angular shape of the armor apparently was a major factor in the relatively low speed of the TSh-3 and thus contributed to its ill fate. So my model gets angular shaped armor :D. For that purpose, I changed the first lower half-former from a curved shape to an angular one.

I'm planning to apply the armor in separate plates, hoping that that's going to give a better effect. As I don't want to lose the seams between the plates after installing them in their place, I decided to fill the balsa ahead of time and get it as smooth as I could as to minimize filling and sanding after installation. I mixed some micro-balloons in 50/50 thinned dope and applied two coats on a sheet of 1/32" balsa and sanded. It feels pretty smooth to my hand but the proof of the pudding will be in the painting.

I installed a piece of 1/16" on either side of the nose -slightly recessed and painted black to give an illusion of depth- which will serve as the mounting plate for the exhaust pipes. I tack glued the armor plates on the fuse and marked the cut lines. Next step is to cut the plates and apply them on the fuse individually.

In the meantime, I also worked on the turtledeck. I decided to lower the stab to line up with the top of the turtledeck, as seen on the only photo that I have. I also slightly changed the shape of the nose, forward of the cockpit. 



Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: Yak 52 on November 14, 2013, 05:34:13 AM
Looking good Ates, lovely work. Are micro balloons lighter than talc for sanding sealer then?

Jon


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 14, 2013, 10:54:56 AM
Thanks Jon.

I switched to micro balloons after I realized how heavy the small talcum powder bottle felt in my hand. Apparently the density ratio is around 10  :o between the two materials (~2.5g/cm3 for talc and 0.15-0.25g/cm3 for micro balloons). I've used the micro balloons in the past for making fillets and such, this is the first time I'm using it as grain filler. I guess the final verdict will wait until the paint is applied. 

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: Prosper on November 14, 2013, 11:04:25 AM
Yeah, talc is very heavy. I bought a small sack of it once - it amazed me how heavy it was to lift - like rock dust or something.

This looks like turning into another handsome model, like the Broussard.

Stephen.


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: PB_guy on November 14, 2013, 01:55:07 PM
I have used a plastic wood filler (actual density undetermined) to use instead of epoxy in certain applications on lighter models because I found it relatively light and cheap.
ian


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 16, 2013, 04:39:36 AM
Today I worked on the armor plates. After cutting them apart I slightly beveled the edges of the individual pieces to emphasize the seams and installed them on the fuselage. So far it looks OK to me, but won't know for sure until after painting.

Rivets, what rivets? (cat's flea comb is suddenly looking like a modeling tool ;D but I guess I'll pass).

Next is the nose block and the "ЛУДИНГ" effect on the cowl ;).


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: Don McLellan on November 16, 2013, 12:36:54 PM
Very, very nice work Ates. 

After looking at the pics in reply #1 above, I think I see the top of the cowl as being flat, rounded and angular(?). 

Don


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 16, 2013, 03:04:10 PM
Don, thank you! You're right about the multiple ways this airplane is depicted. From the specks of information I was able to gather on the plane, I came to believe that the first B&W picture is the only photograph (if it is one, I wouldn't be surprised if that one is fabricated or heavily doctored ;D). Apparently the rest are illustrations based on sketchy data plus some artist's imagination. As such I decided to follow the photograph, though there are still some question marks about that one too, 7x2 exhaust pipes being the most peculiar one :o). I'm also allowing my vision to be conveniently distorted by the sniplets of information I read here and there. This not intended to be a contest model so I'm taking many liberties ;D and using this model as a learning vehicle.

EDIT: I forgot to add,  the top of the cowling was not armored, so I'm going with a rounded top.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 18, 2013, 02:51:31 AM
I spent some time on the cowl and the nose block. I cut the cowl out of 1/32" balsa and after fitting it, I doped and beveled the edges. The nose block is made out of 4 laminations of 1/8" balsa. I'm planning to fit a GizmoGeezer freewheeler (most probably a 8" unit)on it. The GG has a small spinner which somewhat looks like the spinner in the picture if I squint  ;). I'm not exactly satisfied by the shape of the nose block,  but before doing anything about it I'll wait until I install the GG and finish the sheeting around the cockpit to see how everything comes together.


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: bigrip74 on November 18, 2013, 12:16:25 PM
atesus, I like your 90degree method. The fuselage is coming along fine, I also noticed that you are a clean builder.

Bob


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on December 02, 2013, 04:00:52 AM
Thank you Bob  :).

I wasn't able to spend much time on the model within the last week. Here are a few pictures showing what small progress I made in the cockpit area.


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on January 11, 2014, 04:43:51 PM
This project is on hold for a while  :(, until I get a couple planes ready for IWC...

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: GeoffinIN on January 12, 2014, 08:09:24 AM
Interesting subject, beautifully crafted.  Its appearance seems redolent of the Supermarine Type 224  https://www.google.com/search?q=Supermatine+224&rlz=1C1NNVC_enUS490US491&oq=Supermatine+224&aqs=chrome..69i57.5041j0j8&sourceid=chrome&espv=210&es_sm=122&ie=UTF-8


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on January 12, 2014, 11:08:10 AM
Thank you Geoff! I wasn't familiar with the Supermarine Type 224, there are indeed quite a few similarities, thank you for the link.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on June 05, 2015, 09:49:28 PM
I've finally got my act together and resolved to finish my various half-done projects before I move on to something new. TSh-3 is the first one in the queue. I took a long break off of this one, almost a year and a half.

Within that period of time I apparently finished the wing, even sanded it! I didn't think that I did :o...  I added extra ribs at intermediate locations as the ribs looked too sparse once I scaled up to plan from dime-scale to 24" w/s.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on March 04, 2018, 06:02:06 AM
Back at it after another 2.5 years of hiatus. As soon as I went back to this model, I remembered why my enthusiasm had waned away. It's the wheel spats! I did my best to get done with them before I got discouraged again. I'm frankly not very happy with the results but it's gonna have to do :)

And while I'm at it, I put the bones together to see if it looks anything like the subject aircraft. Well, no one I know is sure what the original looked like, I guess I should be fine.

--Ates   


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: faif2d on March 04, 2018, 10:10:51 AM
I have that plan hanging on my shop wall.  I look at it about once a week but have never gone past that. Yours looks very nice!


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on March 14, 2018, 03:49:38 AM
Did some work on the canopy framing and nose block. I fitted this model with a 8" GizmoGeezer prop with spinner. The prop in the picture is something I had laying around, and it looked the part better than the GG unit did.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on October 18, 2019, 03:13:22 AM
12 days shy of 6 years after starting it, the TSh-3 is finally covered and ready for initial trimming. I'll take her to Lost Hills where I hope to find some time away from WC activities and work on trimming. I'll do the detailed finishing afterwards.

--Ates


Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: Prosper on October 18, 2019, 04:53:18 AM
At last! Kudos for sticking at it and a lovely, interesting model Ates. Don't spose you could get the trimming, finishing and final twiddly bits done in the next twelve days, could you? That would be a real anniversary :D.

Stephen.



Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: Pat D on October 18, 2019, 09:02:15 AM
that's a great looking bird there !

must admit I had never heard of this before but it has a really charming shape especially those u/c fairings.

Great Job !

Pat



Title: Re: Kocherigin & Gurevich TSh-3 / TsKB-4
Post by: atesus on November 04, 2019, 01:56:30 PM
Tsh-3 is in the air, finally! More work is needed to finish but I'm quite satisfied with the early performance I've observed this weekend.

https://youtu.be/N7opcJ4WBnY

As is, AUW (no rubber) is 40g. With some luck, I'm hoping to finish it under 50g. The motor is 6g of 4x1/8" SS. I've used an 8" Gizmo Geezer front-end. The rubber seems to hit something inside, not sure where, didn't get a chance to look at it carefully.

--Ates