KC-25 Centuri Honest John Clone

Several years ago I assembled the parts I needed to clone the Centuri KC-25 Honest John. While an older build I decided to share the build here, especially since I just finally got around to painting it almost 12 years later! 

I’ve always liked the Honest John, the Estes Maxi Honest John was one of my favorite rockets as a young rocketeer. It always had a nice slow take off, but was a little scary too since it didn’t go very high, I always prayed for the chutes to open in time! 

I completed gluing the 4 “motor strengthening band” wraps around the body tube, the engine mount, and sanded the fins to shape. 

I painted the 3 smaller 1/8 inch card stock motor bands with thin CA to get a better final finish and to sand and hide the seam. I will do the same to the 1 inch wide band at the bottom after I attach the fins. However one fin will hide the seam on the bottom band.

I deviated from the plans and used a kevlar string tied to the motor mount, rather than cutting slits in the body tube for the shock cord. Strong, and doesn’t ruin the looks of the tube like the orignal plans.

I used masking tape and a flat sanding block to help sand the fins more in the shape of the real rocket’s fins rather than just rounding the leading edge and tapering the trailing edge as the plans suggested. Sorry, my picture of the fin tip showing this is a little blurry. 

Given it’s 3/32 balsa, not sure how much the shape will show when finished, but it didn’t take very long to do.

I glued on the four fins turned out good I think.

I would like to make a note about the Honest John fin marking template that was on the JimZ site. I always check the accuracy of my fin marks by rotating the fin marking template around the body tube and comparing the marks to the template to ensure even spacing around the tube. Glad I do, the marks were off. :surprised: I remarked, still off. I went back and reprinted the template from the PDF to make sure I didn’t have scaling mistakenly on, the template was still short. (For those who might wonder, the tube was raw at this time, no motor bands glued on. The fin templates on the same printed page seem to match the ones I downloaded from YORP so I believe the printed page was scaled correctly. I’m using a Semroc series 8 tube, so I measured the tube’s circumference to an accuracy of 1/50 of an inch, and divided by pi. I could be wrong, but it measured about 0.917 inches outside diameter, which is larger than Semroc lists on their site 0.908, and larger than the 0.907 the 1967 Centuri catalog lists for the Honest John. I know this doesn’t sound like much, but it translates to quite a bit on the circumference. The Semroc tube does have nice thick sidewalls. Inside diameter is correct. Although I measured the fin marking template and it does seem a little on the short side for even a 0.907 tube. In a nutshell the template didn’t work for me, but everything turned out fine. Anyway, always double check your marks before gluing your fins on. I’d be curious what others have experienced with this fin marking template.

Next I worked on the spin rockets. They were not as hard as I first thought they would be, and turned out pretty good. I glued on the launch lug as well. 

And finally it gets some paint!