Polikarpov i-153 "Chaika" (Scratch Build)

JP FPV

New member
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I'm not a huge gamer but when I was playing the game War Thunder I came across this plane.
The nice thing is you can free flight with them and that way you can almost fly every plane from the beginning.
The Polikarpov I-153 stood out because of its gull wing shape.
Flying this plane was horrible at first:D, It had a big torque issue, the powerful engine dropped the left wing so hard I ditched in to the ground ad take off:D..... oeps.

Although small imperfections give a plane its character its not what I want for this build as every one should be able to fly this plane.
That being said this is a intermediate build, now don't let it scare you if this thing flies I will make PDF planes for them and the necessary build instructions.

To be honest I'm a big fan of FPV Cockpits and hopping in to this plane looks so awesome.
You can see the horizon just between the gull wing shape so head tracking is really a must I think or put it on a slider at least.

But first of all lets focus on building one for line of side!

At first I drew a big round body and after cutting it out I totally failed to line the parts out.
After many different tries of designing this thing I finally got something going in Sketchup 2017.
I really had a hard time to make a plane simple in shape.
I started from the beginning and did a square body (Typical FT Style).
That was a goed start as I now had a sturdy base to work on.
Than after that I drew the cowling (Big circle again) it had a lot of gap and thought, can I upgrade the square shape to more 3D look.
And this is what I came op with.
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Its sort of a half octagon if you will and it is very very strong .
The top deck is done by adding formers and a full foamboard turtle deck.
fast forward and you get this.
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I doubled the rudder to make it strong and I'm planning on doing that for the elevator as well.

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I still need to make some small changes to make the build more easy and logical

The dimensions now are:
Span 98cm (39 Inch)
Long 56cm (22 Inch)

(3 Sheets of foamboard)

Hope you guys like it.
 
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Liam B

Well-known member
Yay! War Thunder is an excellent game. Looking forward to this build!

“Hold J to Respawn”:p
 

JP FPV

New member
One thing I am struggling with is which motor/prop combo to use.
You see the tapered nose begins ad 4,5"wide and the cowling widest portion is 6"
I have a NTM Propdrive 28-36 1400 KV laying around which is swinging an 8inch prop.
This means 1 inch of the prop is sticking around the body/cowling.
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Does anybody know wat is the best thing to do here.
I'm thinking I need to step towards a 1000kV Motor and and a 10" to 11" maybe even a 12"prop.
I really would like someones opinion about this.
 

rockyboy

Skill Collector
Mentor
Love this build! Very elegant look!

I think you're on the right track with the lower kV motor and bigger prop - similar to the GeeBee planes, you need to get enough prop out into clear air to take advantage of the thrust.

You're also on to a good thing with doubling up the tail surfaces - I did that on my Caudron C.460 design and it ended up being one of the strongest parts of the plane. No matter how many prototypes I smashed into the ground, the tail always came through without damage :black_eyed:
 

bpw823

Junior Mastermind
Woah! What a build! I play WT all the time and love finding airplanes to build there. When you've finalized the design I'd love to see a build video of sorts to see how the model went together. Very accurate!
 

PsyBorg

Wake up! Time to fly!
Really cool design and a very clean build. Fpv with head tracking would be awesome if you have the skills to take off and land like that.

Looking at that huge cowl I wonder if you could open channels in the front to allow air to flow thru the cowl and out the side to be sort of like a ducted fan action. I think allowing the air to pass thru a portion of that would lessen the drag and aid the motor and prop with cooling and better efficiency of air flow. I am probably wrong but that's how my head works with things like this.
 

JP FPV

New member
Thanks rockyboy the Geebee is a good plane to compare it with, I didn't thought about that one.
I looked ad your Caudron C.460, that thing looks fast, really cool racer-style.
I destroyed the tail of an airplane ones but lets not go that way:rolleyes:.

He PryBorg that might be a good idea actually to make some ducts.
If i find that the nose is to bulky I will try that.
The full scale version has (I believe) 6 exhausts in the cowling and could be used as ducts maybe

I also got a good old DT750 laying around that is swinging a 11x4.7 Slowflyer Prop.
I don't know if it is enough for this model but it might do its first maiden with that.
I'm scared that this KV is to low for the plane.

While mounting it all together I think I'm getting in to trouble with the CG.
So to make the next model I might shove the wings a little bit more backwards and sacrifice some scale.
As specially when I double the elevator.
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rockyboy

Skill Collector
Mentor
How is your all up weight coming in on the plane?

That DT750 with the 11x4.7 should give you a healthy 1250g or so of thrust on a 3s, but if you need a little more a 12x3.8 gets you into the 1500g thrust range (but also at risk of going over the amp rating at 100% throttle).

Gotta say it looks really nice on there though :)
 

Sir Fly

New member
WOW THAT IS AMAZING! I also play War Thunder (or used to :( ), and this looks so iconic and realistic! Really amazing. Subscribed!
 

localfiend

I like 3D printers...
Mentor
Very cool man. I started plans for one of these a year ago, and I think I have some wing prototypes in the basement still. You did such a nice job I'm not gonna bother finishing mine.

Gonna release plans? What's the wingspan? Any thoughts on retracts?

I've got a Tacon Bigfoot .46 670kv waiting for one of these.
 

JP FPV

New member
Thanks for the feecback, nice to se you all like it.
Wingspan is 39"
Overal weight is around 600grams including 1300 3s

It's now ready for its maiden. Its pritty windy these days so ill have to wait.
When everything turns out well I can start on making the PDF plans and build instructions.

Retracts... I did thought about it but space would be an issue in that spot.
 
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PsyBorg

Wake up! Time to fly!
What about a folding mechanism like the PBY Catalinas use? The retracts push out and down and the wheel comes straight out of the fuselage and slightly downward? Would better suit the profile of the plane and give it a naturally wider stance I would think.
 

Sir Fly

New member
What about a folding mechanism like the PBY Catalinas use? The retracts push out and down and the wheel comes straight out of the fuselage and slightly downward? Would better suit the profile of the plane and give it a naturally wider stance I would think.

The Chaika had folding retracts that fit into the wing like the P- 40, except closer to the fuselage.
 

willsonman

Builder Extraordinare
Mentor
As I own a Gee Bee... Mine uses a prop that has only one inch of prop larger than the radius of the fusealge... 9" fuselage... 11" prop. She goes around the field just fine. While there is little in the way of prop exposure at the tip, the tip ends up doing the most of the work in the thrust department because it is rotating the fastest... that is centrifugal motion for you.
 

JP FPV

New member
Thanks Wilsonman that makes me a lot more at ease knowing that.
The round nose should help get a bit more around the body I think in that case.
I tapered the nose so that should leave me with a 4,5" flat piece
with a 11"prop.
I may me wrong though.:black_eyed:
 

JP FPV

New member
The Maiden

It flew and it was horrible :D.
but it will fly again.
At the start the plane did a knife-edge, so I trimmed the plane out but it was hard to steer.
After some wiggling around I found out something strange.
When I gave A roll input the plane banked 5 to 10 degrees and stopped rolling.
But when I gave a rudder input the plane extremely ROLLED! to one side.
So I am going to do make it in to a 3 channel as it is strongly asking for it :eek:.
(It's really strange to have the roll and yaw axis reversed:D)

The motor setup is also not the best.
I think I'm going to order a new one.
It has to be more of a 1200Kv and maybe not a slow flyer prop.
The plane tried to be more in a hover than in forward flight.

But the thing that worried me the most was the CG.
I put a 1300mA 3S all the way in the front and guess what.... it was nose heavy so I'm really happy with that.
Now a 2200 can be used I think.

It's not the best video but this will change when it flies better.
Here's the maiden!!!!!