This is a easy 18mm, tumble recovery oddroc. Art Applewhite is known for making odd rockets. His hour glasses are no exception to this. A variation on a spool rocket, the hourglass looks odd but flies well and uses a minimalist approach to make something unusual and fun.
The kit comes with a piece of printed cardstock (mine was yellow), a piece of foamboard, a motor tube, an engine hook and the instructions. Other than that, you need white glue and an exacto knife. Scissors helped out as well.
Construction was supposed to begin with the cones but I had the sheet turned over, saw the motor mount and got to work figuring its some kind of law that you always begin with the motor mount. I should have known better.
I cut a slit a 1/4" from one end of the motor tube and slipped in the hook. I then cut out the motor tube wrap, applied some white glue on the back and wrapped it around the center of the motor tube, making sure to keep the dashed lines aligned on either side of the hook. I used a little bit of cellophane to hold it down tight as it dried.
It was at this point I realized that I had not begun at the beginning and flipped the instructions over. I then learned that I should have started by cutting out the cones. It seemed that no harm had been done so I cut them out using scissors except for the launch lug holes, where I used an Exacto. I put a little glue on the tab and formed the cone. A few moments later, I did the second one.
The next step involved cutting out the card stock rectangle containing the two bulkheads. When the rectangle was cut out, some glue was applied to the back and the card stock was pressed flat on the foamboard. This was allowed to dry.
The next step is what took time. After the glue was dry from the previous step and Xacto blade was used to cut out the inner cavities from the bulkheads and then cut the bulkheads themselves out. This is best done in small steps and changing the blade along the way is recommended. Eventually, I had something approximately right and used sandpaper to even up the edges.
The rest of the assembly is pretty straightfoward. The motor tube is glued on flush and perpendicular to the after bulkhead, one of the cones is slipped on and filleted into place, the second cone is likewise put on and then the forward bulkhead is glued into place. Care must be maintained so that all the lug holes line up; I did that with a shot section of rod. Then everything was filleted and constructions was complete.
This rocket really does not need finishing since the colored carstock serves that purpose. Never-the-less, there are instructions for painting. The critical step seems to be to use glue to seal the edges of the foam board so that the paint solvent does not disolve it.
If I were to request one change in this kit, it would be for a second piece of cardstock to glue on the opposite side. It would not even need any printing since the template function would be taken care of with the first peice of cardstock. All that being said, I decided to paint the rocket. I used white glue, as per the instructions, to seal the edges of the foam board. After 2 coats of glue had dried, I gave it a light mist of yellow. I wanted to put on several light coats that would be almost dry by the time they touched the rocket figuring that, eventually, the dried paint itself would build up a protective barrier to protect the foam from further paint solvents.
Construction Rating: 4 out of 5
I am loathe to use any of my hoard of booster motors unless I must. So I didn't use a sigle one of the recommended motors.
First up, I tried an A6-4. Prepping was easy. install the igniter in the motor and stuff the motor in the rocket. Hook up wires and push the button. It took off well enough, did not go very high but started doing a crazy spinning about all axes as soon as the thrust ended. The instruction warned that this was normal and the rocket still kept moving upwards until gravity won out and it started down.
The second flight was on a B6-4. Except for going significantly higher, the flight profile was the same as with the first flight. The same cannot be said of the third flight.
The third was on a C6-5. It started to boost like the others but then the crazy spinning started well before boost phase ended. This led to a rather eratic flight but at least it stayed in the air.
PROs: it is odd and will not be too easily lost
CONs: the eratic spinning was expected but not during boost.
Recovery is simple. Gravity has its way and the rocket tumbles down without any fuss. No prepping, no un-tangling.
Flight Rating: 3 out of 5
I'm glad to have built this one but it will never be one of my favorites. I will keep it around for the odd factor, though.
Overall Rating: 3 out of 5