FlisKits Praetor and Praetor-II Build

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With the 7th anniversary of FlisKits right around the corner, I thought that I better build the kit that I won last year during their 6th anniversary celebration. As a side note, I was 10th on the list for kit selection and I choose the Praetor. The great part about it is that if I was 1st I would have still selected this kit. I have always wanted to build one since seeing it hanging in my LHS. When I received my box from FlisKits, I was pleasantly surprised to see that Jim had included a Praetor-II booster with the kit.

Here are the parts for the Praetor set out and ready to go. It is much larger than I thought it was from first looking at the package hanging on a hook.

--- Ron

 

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As with most rocket kits, you start with the motor mount. It is pretty standard. While you can’t see it in this picture, I went ahead attached Kevlar to the motor mount for the recovery system. The kit uses the tri-fold paper mount system in the instructions.

--- Ron

 

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In the kit you get 2 very nice pieces of balsa to cut the fins from. While I do like laser cut fins, there are times that I like to cut my own fins to enhance the construction process. This was one of those times since it is the fins that make this rocket so unique. Here is a picture of the suggested cutting pattern for the balsa. The smaller outlined piece is for the launch lug standoff.

--- Ron

 

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Since the fins are so long, I thought long and hard about whether I wanted to paper them for added strength. I decided not to do it so we will see if that decision comes back and haunts me after a couple of flights. To attach them to the body tube I used a straight pin to poke a series of holes in the body tube and root edge of the fin (my picture of this did not turn out in focus). I then used some medium CA to attach the fin to the BT while using the pin to push the CA into the holes (this decision does come back to cause me more work). This creates a rivet like joint that seems quite strong. Here is a shot of one of the fins drying during gluing.

--- Ron

 

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Here is a picture of the nearly completed Praetor. I just need to attach the launch lugs, fillet the fins (yummy ) and finish the parachute.

--- Ron

 

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Now comes the Praetor-II booster unit. Here are the parts before assembly begins. I must say that the design keeps in the spirit with the Praetor and adds more character than I thought possible when attached to the rocket.

--- Ron

 

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Here’s the suggested cut pattern for the balsa with the fin template. The balsa was as good in quality as the Praetor. So good in fact I decided not to fill the fins and just used a couple of coats of Kilz as the base coat.

--- Ron

 

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The Praetor-II uses gap staging. The instructions call for you to cut a couple of vent holes along two of the fin lines. What I like to do is use a hole punch to accomplish this. I punched the holes 3/8” down from the top of the tube. Then I put in the coupler and marked my holes, removed it, then punched holes in the coupler. The only change I would do differently is to offset the holes 45 degrees from the fins. Once I glued the coupler to the lower tube, I test fitted the assembly into the Praetor. This is when I discovered a gotcha that I made mention of before. The CA rivet joints that were in the lower section of the rocket prevented the coupler from going into the tube all the way. I had to use an Exacto knife and sand paper to flatten them out. After that everything fit fine.

--- Ron

 

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As I said before, I used a couple of coats of Kilz for the base coat. This filled the tube spiral and most of the gain in the fins. What I should have done is used Fill ‘n Finish on the nose cone before painting. You can see some of the gain on the NC. I choose to paint the rocket orange, silver, and purple. I am pretty please with the final result. Here is a picture. I hope to be at the Sept 12th launch of OREO (Oregon Rocketry Enthusiasts Organization) for the Praetor's first flight. Wish me luck.

--- Ron

 

[jflis]

Oh man, that thing came out SWEET!

One question on the paint. On the Praetor you have purple fins with orange tips. Then, on the booster you have orange fins. How do you think contrasting purple tips would look on the booster?

One reaction to the Praetor I always enjoy is the surprise folks get when they see how large a rocket they get out of that little package

Good stuff!
jim