Launch report & aerial photos

I recently had a successful test flight of my newest and most sophisticated rocket to date. This is a 2.6" rocket with a 54mm motor mount, designed for two-stage flights.

The interstage coupler has thin carbon fiber rods that slide into channels between the second stage's motor mount tube and airframe. A PerfectFlite mini-timer is built into the coupler, along with a locator siren to assist in recovery of the booster.

The second stage uses a PerfectFlite altimeter for deployment, in a unique ducted electronics bay which permits use of motor ejection as a backup. The power switch and ejection charge connections are on the outside the bay's access panel. A separate, smaller panel provides access for install the ejection charges. The whole setup is intended to make prep fast and easy.

The 35mm camera payload is controlled by a custom electronic timer and also contains a locator siren.

The test flight was made using an I284 in the first stage, and a J90 in the second stage. Another, smaller rocket, powered by an H97, was launched alongside the large rocket in hopes of getting pics of it in flight.

The flight of the two-stager went very well, with only two small problems. First, the interstage coupler drag-separated where it joins the booster. Ignition of the second stage motor occurred at about the same time, before the igniter could be pulled out of the motor. However, the drag-separation did cause the second stage to angle over a bit.

The second problem occurred at ejection when the motor retention failed, resulting in the loss of a brand new casing.

Altitude was 5602 feet. All components except for the lost motor were quickly and safely recovered. I then spent the next several hours searching fruitlessly for the motor, in temps that reached 115 degrees, before calling it a day. The photos from both flights turned out great, and can be seen here:

https://albums.photo.epson.com/j/AlbumIndex?u=3009006&a=30098271&f=0

That shot at apogee is stunning! You get a feeling for the height the rocket got!

Thanks for the pics.
Pat

I liked the staging shot too. too bad about losing the motor.

Ray, would you explain a bit more about building the booster stage, lining up the carbon fiber rods, how to drill holes in the sustainer MMT rings, etc.!

Awesome pics Ray!

Awesome pictures! And wasn't your rocket featured in Extreme Rocketry a while back?

Originally posted by cls
I liked the staging shot too. too bad about losing the motor.

Ray, would you explain a bit more about building the booster stage, lining up the carbon fiber rods, how to drill holes in the sustainer MMT rings, etc.!

Click to expand...

I plan to post some construction pics (and will likely do a detailed article for ER) but for now I'll try to explain using only words. Basically what I did was this:

1. Mark the positions of the fins on the motor tube.

2. Glue the centering rings onto the motor tube.

3. Glue the fins onto the motor tube.

4. I glued 1/8" square strips of wood at the base of each fin, one on each side, to provide a more secure anchor for the fins.

5. Glued a second set of 1/8" wood strips parallel to the fins, spaced about 3/16" from the strips at the base of the fins. This formed the channels for the carbon rods.

6. Using a dremel, I cut gaps in the aft centering ring, to create the openings into the channels.

7. Slotted the airframe tube to slip over the motor mount/fin assembly, and glued it in place.


The interstage coupler was made using a short section of 2.6" airframe tube and a coupler. I lined up the airframe tube to the aft end of the second stage tail and marked the positions of the channels.

The tricky part was that the rods had to be glued to the inside of this airframe tube, extending about halfway down into the tube, and had to be lined up as straight as possible. To do this, I first drew lines on the outside of the tube, running the full length of the tube, and used those to position a straight edge so that I could draw lines on the inside of the tube.

The carbon fiber rods I used are not round, they are about 1/16" thick by 1/8" wide. Later I found that this thickness would not provide enough rigidity, so I doubled it by gluing two of them together. If you can find rods that are 1/8" square, you could skip that step. I cut eight rods, six inches long. I made a mark on each of them to show the halfway point.

The rods were then glued into the short airframe tube, carefully lining them up to the lines marked inside the tube. The channels they fit into are wide enough to allow a little bit of imprecision.

Once the rods were in place, I glued in a bulkhead, butted up against the ends of the rods inside the tube.

The coupler tube is removable, and held in place with small screws. I mounted the timer and its 9v battery to one side of a sheet of rigid plastic (thin plywood would work just as well). On the other side, I mounted the locator siren and its battery pack (it uses 2 AAA batteries).

This slides down into the coupler tube. On the side where the timer is, I cut an opening in the coupler tube for access to the timer. I cut a matching opening in the airframe tube, except a bit larger. This was used to make the access panel. The timer's power switch is mounted on the access panel, and when the coupler is installed, the access panel is held in place with four small screws.

Leads from the timer extend through a small hole in the access panel, and connect to a pair of small screws. These are the connection points for the igniter leads.

When prepping the rocket, the igniter is installed in the second stage motor and lightly taped in place. The booster is placed on the pad first, then the second stage rocket. The igniter leads are draped over the lip of the interstage coupler, which has a small notch cut into it for this purpose. Slide the rods into the channels until the aft end of the second stage rocket rests on the lip of the interstage coupler.

Connect the igniter leads to timer output leads, and when you're ready to launch, turn the timer on. The timer is G-switch activated so there's nothing else to connect.

Hope this makes sense!

Originally posted by Rocket Guy 1317
Awesome pictures! And wasn't your rocket featured in Extreme Rocketry a while back?

Click to expand...

Thanks! I've had a few articles in ER, and was the subject of one of their interviews once. The most recent issue had a short article of mine about making transition sections.

I also wrote a booklet for ER called "A Guide to Staging High Power Rockets". I've written another one on rocket aerial photography which is due out in print anytime now.