Upscale Fliskits Flea - 'The Tick' HPR build

This is a 'scratch kit' build of an upscale design of the Fliskits Flea that I'm calling 'The Tick' (my 8yr old son came up with the name, ticks are bigger than fleas was his reasoning!). Just getting started, and this will probably be a long running thread.

I say 'scratch kit' because other than some 1/2" plywood bulkheads that I'll cut with my Dremel circle cutter jig (you can see one bottom center in the first pic), and the plywood portion of the fins, I am using purchased off the shelf parts and some custom ordered components.



The rocket will use a 54mm motor mount and 4" body tube - all tubes are Blue Tube that I ordered from www.alwaysreadyrocketry.com. You can see the 27" motor mount tube already cut to size - I used my chop saw, which is always fitted with a fine finish blade. It gives a good clean cut on the Blue Tube material, which is fairly hard and doesn't fray on cutting.

I've also built the altimeter bay already. West Systems 105/205 was used on the coupler construction, and some T-88 holds the nuts on one end in place.

My plan for the fins is a laminated design. The core is the G-10 fins you see on the left, which I ordered custom from www.publicmissiles.com. (Kim in sales was great to work with - I highly recommend this vendor.) The surfaces will be 1/8 birch plywood (which you can see with the templates drawn), which I ordered from www.woodworkerssource.com, and they will be bonded to the G-10 cores with a layer of fiberglass cloth (weight TBD) and the West Systems 105/205, as in wood-cloth/epoxy-G10-cloth/epoxy-wood. The rocket could break Mach 1, so I decided to overbuild a bit and make the fins extra stiff, hence the laminated design. Once installed the entire fin can will also be glassed. I will probably also bond a rounded dowel to the fin edges.

Here is the basic look from Open Rocket:



One component I don't yet have is the nose. Jim Flis was kind enough to provide me with a scaled up drawing for a 4" version of the original nose. It's not quite what you see in the picture above, more like a conic with a rounded tip (will post it at a later date). I will be contacting some of the vendors who frequent TRF for bids on the nose job (!).

That's all for now. We are having a 50 degree day here in Boston today, so good chance I'll be out in the garage working on this. I'll do my best to post regularly, but not necessarily in gory detail. I still have quite a few construction decisions to make and will definitely ask you all for input (God help me!).

To the garage!

Bet Sandman could make that nose for you. He's done a bunch for me, and his work is always excellent. He could even cut the shoulder down to fit in a coupler, if you wanted to use shear pins...

Anyways... looks like a fun project!



Later!

--Coop

Good tip Coop. My current thinking is that the nose will be fixed in place (either screws into threaded inserts or plastic rivets) and that I will mount a bulkhead directly behind or possibly in the shoulder, with a forged eyebolt attached. Then separation will happen at the base of the payload section, which will house the main chute. Also planning to use an anti zipper 'soft ball of something' approach to protect the base of the payload section. But it's early in the build - I may rethink some or all of that as this moves forward.

Aaah... gotcha.

If you have a NC turned for you, though... would a bulkhead be necessary? Turned from solid wood, you could simply screw the upper airframe to the NC directly --or install screw inserts, no?


Later!

--Coop

I saw the title, and immediately thought of this guy...

If the cone is wood, absolutely. I haven't decided on material yet but am leaning fiberglass, in which case I would need a bulkhead.

The plywood fin sheet clamped and ready for the first cut. I'll make the longer cuts with the circular saw using a 60 tooth finish blade, a technique I've used in the past to cleanly cut sheet wood.

K'Tesh said:

I saw the title, and immediately thought of this guy...

Click to expand...

Hmm, you've given me a decal idea K'Tesh!

Fin #4 ready for cleaning (the G-10, to remove any manufacturing residue), sanding and bonding. 3 to go.

K'Tesh said:

I saw the title, and immediately thought of this guy...

Click to expand...

Me too!:grin:

Done cutting the plywood fin laminates. Took around 2 hours clock time, spread out over most of today.



Suggestions for how to best clean the G-10 before sanding and bonding?

Finally getting back to this build after spending most of my rocket time getting ready for the launch season and doing those initial spring launches.

I used mineral spirits and a lint free cloth to clean the ring, and JB Weld to epoxy it on. This is the forward fin ring (the one that the forward end of the fin tabs will butt up against). Nice and perpendicular to the tube axis, bond appears to be solid.

I just got a supply of 4"+ 4"+ basswood.

Actually it's a beam 7' long and 4"+ x 9"+.

I also got a few blocks of "ROCK HARD" balsa from Lone Star balsa before they closed but they are only 6" long.

That balsa is almost as hard as basswood but a bit lighter...but not much lighter!

I haven't thought about my nosecone issue in a while - other than, I need to get one, and, on the biggest L motor it can take, this rocket will pass Mach 1, and so nose needs to be able to handle that. I'll email you Sandman when I get closer to that stage of the build.

Goal for this weekend is to construct the fins. One completed yesterday, another clamped and curing right now. It's a laminated fin as I've mentioned before - 1/8" plywood faces, a G-10 core, and 1-1/2 oz fiberglass cloth between each layer. West Systems 105/205 for bonding. They will be solid, stiff and hopefully bulletproof.

Meant to post the completed fins - came out nicely. Very solid. Still need to sand them - good job for my new orbital palm sander.

Finished building the slotting sled and cut a test slot in a scrap section of blue tube. Still need to get an 11/32" straight cut router bit to cut the Tick fin slots.

Looking good! I have a 24mm upscale based on the BT-70 that I call Super-Flea . Fun to fly!


Sent from my iPad using Rocketry Forum

Thanks Jim, it's coming along. Once I get the router bit for the slots the booster section will go together pretty quickly. Then time to get a nose built (thanks again for the spec diagram!)

- Matt

The 11/32" router bit arrived yesterday, my quart kit of Aeropoxy ES6279 the day before, I'm off work until Monday - time to build a fin can.

The slots came out well - practiced a lot on a scrap of Blue Tube to get the hang of using the sled.



Those fins want to be attached!



Slid the motor tube in and used some tape to check rough alignment - easily passed the eyeball test, so I don't see any issues getting the fins in straight (I built a basic jig to help).



Can construction begins tomorrow.

Yesterday I epoxied the forward centering ring to the motor tube. Today I used Aeropoxy ES6279 to install the motor mount in the body tube.



Also used West Systems 105/205 to secure the stiffening couplers. The 4-fin design weakens the aft end, so I decided to reinforce.



I'll rout out the cardboard that's covering the fin slots once the epoxy cures.



Should be able to start fin attachment tomorrow.

Make that tonight. Easily routed out the cardboard, so went ahead and installed the first fin. That CR and clamp are to keep the motor tube centered while the first fin sets.

Another view of the fin jig in action.



Yes I'm using one of the other fins for the shim.

Starting to look like a booster section. The last fin is curing in the jig.

Done with main booster assembly. Fin fillets in place, touching them up a bit. Used West Systems 105/205 mixed with the 406 colloidal silica for the fillets.

First application of Bondo to smooth out the fillet area.

Also built and installed the shock cord anchor assembly. Short piece of coupler with two 1/4" plywood bulkheads (one OD, the other ID diameter to form a cap) and a forged eyebolt. Assembled and installed with T-88 epoxy.

Mounted the switches in the electronics bay. Will get the ejection and telemetry systems installed and wired next, and drill the sled to hold altimeters, batteries and an XBee.

Started work mounting electronics on the sled. Asking about LiPo battery mounting on another thread.

https://www.rocketryforum.com/showthread.php?t=69320

Mounted all the ejection hardware, wired the bay (minus the XBee). Just about ready to epoxy the fixed end into the bay body.



Using a fully redundant dual deploy approach (good practice I suppose for an eventual L3).