Another Japanese rocket fighter concept: The ”Rammer”

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tab28682

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I had so much fun doing the Mizuno Shinryu rocket fighter, I decided to do another WWII Japanese rocket fighter design proposal that was never built.

The Kokukyoko Syusuishiki Kayaku (“Autumn Water”) started as an unmanned remote control missile project in 1945, intended to engage enemy bombers in a ramming attack. No warhead was installed. The unmanned aircraft was built to (hopefully) survive hitting the tail of a bomber, so it could be recovered and used again.

Unsurprisingly, a piloted version was designed as well. A mock-up was built, but as with so many Axis late war desperation projects, there was no time to get it built and operational before the war ended.

This design is almost a 3FNC project. Performance should be very high if done with a PNC-80K nose and BT-80. Might be more sensible to use 3”’ PSII to make it a little easier to see at altitude.

The tailless swept wing design will keep the CG fairly close to the motor casing and help minimize ballast.

Different illustrations of the design show differing wing planforms, so there is a lot of design freedom there.

The canopy could be a simple Depron box with painted windows, or it could be a built up part using flat sections of transparent plastic.

Should be a quick and easy build. Paint and markings will take more time than construction.

Unicraft produced a 1/72 scale resin model of the Rammer.
 

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Brian V

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Good evening Tom was just checking in to see how this project is coming along? I’m really interested in seeing how it comes out! Take care!😃👍
 

tab28682

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Not a lot of progress yet. Have been sketching on some scaled up pictures. I did decide on doing it with Estes 3” parts. It was just a little too small at 2.6”.

Picking up some Depron from RC Depron in Waco this week for this and other projects.
 

Brian V

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Cool I was thinking about it last night thought I check in. Just me be curious 😃👍
 

tab28682

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3” cone and tubing are now on order from Estes. Also ordered extra 3” parts for a RC RG design for the H13 motor.
 

burkefj

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I found the 3" parts were heavy for an E6 class rc rg but perfect for the H13 size.

Frank

3” cone and tubing are now on order from Estes. Also ordered extra 3” parts for a RC RG design for the H13 motor.
 

tab28682

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I found the 3" parts were heavy for an E6 class rc rg but perfect for the H13 size.

Frank
This thing will only use about 3” of tubing. I think it will be ok. If not, I will peel the tubing and print a lighter nose cone.
 

tab28682

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While digging through the chaos in my model room today, I found a rocket kit hat I had completely forgotten about for a number of years.

As luck would have it, it was an Estes Big Daddy....:)

I instantly decided to divert its useful parts into service for the Rammer build. Nice lightweight 3" parts. Just enough unslotted tubing to build the airframe

A shame that Estes does not stock and sell these exact parts.

Hope to have the basic Rammer built by the weekend.
 

Brian V

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You got to love when you find a kit that you forgot about and go directly to kit bashing 😃👍 I like it👌
 

tab28682

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Flying WWII Japanese aircraft as model rockets is TIGHT! :)
If you like it, I must be doing something right! Or, at least, interestingly strange....:)

As it turned out, it used most of the Big Daddy tubing, including about half the fin slots. I filled in the ones on the sides and will use the top slot, extended, for the vertical tail. The lower slot will be mostly covered by the skid.

One interesting problem is that I have to slot nearly all of the length of the tube for the wing. I want the wing in something like the "scale" location, low on the airframe but not glued to the outside of the tube. There will be a small section of the tube below the wing and the skid will be below that.

I have an idea for a jig that will keep the tubing circular while it is being glued to the wings.

More to come.

A Big Daddy kit is only 20.97 from A.C. Suppy. Would be useful for parts for other rocket gliders if the tubing was longer and unslotted.

My tubing from Estes showed up. Turns out the 3" tubing is the same as the Big Daddy tubing. The 3" PSII cone is 3.5 is untrimmed, while the trimmed Big Daddy nose cone is just 2.1 oz.

The tube and cone for the Rammer is 3.1oz, which is doable for a model that will weigh about 10.5 to 11.5 on the pad.
 
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Daddyisabar

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It is a lot of fun to kitbash and use odds and ends parts to make old airplane rockets. I started with Estes Spaceship One, Baby Bertha and cluster bomb kits. Then moved to old TLP kits. Parts is parts! Scratch building oddrocs rules! Love the Japanese planes. I have done a Kyushu J7W Shinden, Aichi D3A Val and Nakajima B6N Tenzan.
IMG_20180511_211856418_HDR.jpg
 

Daddyisabar

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Several different ways for low and high wing mounting. Wood glue, epoxy, TTW, tabbed, surface mount reinforced, single or multiple piece. So many problems...How much can I push the envelope on asymmetric drag and keep it balanced...How much nose weight to keep it stable...Will the RSO send me packing?
IMG_20180327_220608282.jpg
IMG_20140630_190643384.jpg
 

tab28682

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That is one really impressive body of work, Daddy! Thanks for posting the group pics.

However, when it comes to rockets shaped like airplanes: I really like the ones that are rockets that do not glide, but I LOVE rockets that glide, and I love RC rocket gliders most of all….:)

Made a little more progress on the Rammer yesterday. Wings and tail are cut out and wings are ready for spars and hinging. Have cut and fitted some of the parts of the cockpit fairing. Pics soon.
 
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