On Monday, I designed built, flew, and lost a little test bed Ohka Glider. Ok, “designed” might be a stretch – I participated in an online Ohka JetCat build back in 1999 or so, and I started with my rough plan from that time.
The glider is small – only a 9″ wing span – but it was fun to shoot around the back yard. It really wanted to zoom and would gain great height on low power and a nearly flat launch. I pushed my luck too far,launched too high and the wind and glide took it into my treeline, near the top of a tall pine. It was a quick build (and a little twitchy), so I wasn’t too upset.
Don DeLoach commented that the tail looked too small. I had already enlarged it once, but trusted Don’s advise (as we all should) and scaled it up again for build #2. Build #2 took place yesterday and I decided two things: 1) photo-document the whole thing and 2) go with full decoration. What follows is my build process, with some explanations of why I do certain things.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess01.jpg)
the laser-cut parts. top-to-bottom: 1/64th ply, two sheets of 1/32″ balsa, and one sheet of 1/16″ balsa
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess02.jpg)
an experiment in #1 that continued into #2. I replaced the nose of the main fuselage with 1/64″ plywood. The nose takes a lot of stress and needs to be strong.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess03.jpg)
I have some 1/8″ wide carbon fiber ribbon that is 0.005″ thick. I cut this to the length of the fuselage, tip-to-tip, and split it to 2 strips 1/16″ wide. This will be on either side of the main fuselage to add a great deal of strength.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess04.jpg)
I pinned down the fuselage side and drew a line tip-to-tip where i wanted the carbon fiber to go. I am using medium CA. It gives you a little time once you put the strip down, but locate the strip quickly.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess05.jpg)
the carbon fiber strip is in the proper location and I an pressing and rubbing it down with the flat end of an xacto handle. Press and force out the excess glue.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess06.jpg)
do the same to the other side. Once the glue was pressed out, I wiped down excess with a piece of scrap balsa.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess07.jpg)
I designed nose doublers to add even more strength. Before I glue them on, I feather the trailing edge so that there is less of a “step” there on the fuselage.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess08.jpg)
There is one for each side. They cover the ply-balsa joint, cover the carbon fiber strip, and extend past the wing to give full support there, also. Given that I need nose weight, I could have done two ply sides over a solid 1/32″ fuselage, but this works just fine. Note that they are also somewhat cross-grained to the main fuselage.
![](https://volareproducts.com/blog/wp-content/uploads/OhkaProcess09-928x1024.jpg)
This shows the CA over the entire area. You don’t want any separation anywhere. I used an “x” on both pieces so that I knew which side was to be glued and which side was to be sanded. Make one left and one right!
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess10.jpg)
Did I mention that the nose takes a lot of abuse? After the sandwiched CA is set, I ran thin CA around the edge to soak into those joints and inside the hook. Then I coated the front part of the nose with thin CA.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess11.jpg)
The leading edges on Build #1 took a beating, so I am using bass leading edges. Bass isn’t super hard, but it is better than light balsa.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess12.jpg)
All parts ready for a) assembly or b) covering! I feathered the trailing edges of the wings and did a little of the same on the tail pieces. All surfaces were sanded smooth and edges rounded.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess13.jpg)
Printed Tissue! This is a tutorial for another time, but I basically take the plan, a good 3-view, a select color, assorted graphics and layer them in Photoshop. Printed on white Esaki through my Epson printer.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess14.jpg)
Cover just like any other model. I coat the entire surface with UHU (yeah, that’s purple UHU – it fades over time and the label peeled off) and cover with dry tissue.
![](https://volareproducts.com/new2024/wp-content/uploads/2017/06/OhkaProcess15.jpg)
all parts covered and ready for assembly. Notice there is no black CF stripe down the side of the fuselage. I glued an strip of 1/32″ balsa over the CF strip and sanded it down until there was almost nothing left – just to “hide’ that black strip.
I am happy to report that Ohka #2 has NOT been lost. I stopped testing short of that. I probably had well over 100 flights on the #1 on Monday – it was just too much fun and showed little glimmers of promise. #2 is much more stable and predictable and pushed the limits of my small field inside of 10 flights. I would have a video here, but I can’t figure out how to launch a jet cat and film it at the same time.
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Theres a lot of good ideas incorporated into the build. Thanks for this posting. I am really looking forward to shooting this one off. By the way i was very pleasantly surprised by the posting about the F-4, thanks very much.