Going for 100,000 Feet

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I was thinking about that myself for two reasons. It is hard to hear the altimeter beeping behind FG. If I added another vent over the magnetic switch I could see the light from it as well as hear the beeps. And it would give me a second hole.
 
Ended up not test flying the sustainer. had a CATO on another flight and needed to pull the tracker out of DO to use for other rockets. The sims are both under 18,000' so I think I am safe. I will be getting it ready for its flight on the weekend of URRF 4.
 
Ordered the motors from AMW. Final decision was based on what was in stock. Booster will be a CTI H399 (282 NS). Sustainer will be a CTI I-204 (348 NS). 630 total NS. A full I is 640 so I should be set for the altitude record attempt. RAS Aero and Open Rocket sims are about 400' apart with RAS Aero showing 17,600' and OR showing 17,200'. I need to run then flat wire through the sustainer airframe, test the leads, and then I should be done and ready to go.
 
Well... In about 12 hours this bird flies. Had to make some major changes to the electrical system. The flat wire was still too thick and the motor would not fit with it inside the airframe. So I attached it externally. The wire runs most of the length of the airframe and stops about 2" away from the forward end. There, I drilled holes through the airframe and soldered telephone wires that connect to wires coming out of the AV bay. On the aft end 30 ga. shielded magnetic wire will allow it to go back inside the interstage coupler and connect to the separation charge and the sustainer igniter.

Not as pretty, but it should be functional.

Here is the final build photo. Wish me luck.

Do 15.jpg
 
Hope the flight goes well! Should be on you way to the pad about now!
 
SUCCESS!!!!

High baro pressure, squirrelly transonic flight (yeah the fins were a little too small), and increased drag due to the running of flat wire externally limited the altitude to 15,101 AGL, But the rocket flew as planned. Stage separation occurred immediately at booster burnout and the sustainer fired approx 2-2.5 seconds after separation.

It took five hours to find. Thanks to Nat Kinsey who located it in a cow pasture. I had looked for 3 hours then came back. Someone else recovered the booster. I found the break-away rail guides, then we all started talking about winds above 7,000'. Someone mentioned a drift rate of 100 FPS for a larger rocket and I realized that it had landed farther away than I initially thought. So we went over the hill. Nat and I, coming from opposite directions, picked up the signal about the same time. He found it. According to Google Earth distance was approx. 3.1-3.2 miles away.

Below is a screen capture from the launch plus telemetry information. There was unfortunately no onboard video because we had to wait for cloud cover to clear. To my knowledge there is no Tripoli Complex I record, so this flight will be submitted.

Do 16.jpgDo 16a.jpgDo 16b.jpgDo 16c.jpgDo 16d.jpg

Now it is on to Re...
 
$_1.JPG
 
Nice flight. If you're flying to 15K, you should keep an eye on the upper level winds. Here's a site I like:

https://www.aviationweather.gov/windtemp/plot

I don't know what flat wire you used, but if it's Gecko Wire, aka Tapper Wire, then you can peel off the heavy wear layer on top. What's left is very thin. The top is then sticky, and I just cover that with scotch tape of something similar.

Jim
 
Congrats!

Did you not get GPS packets on the way down? Or was it just drifting so fast that the last packet was way off?
 
This was a similar product made in Canada. Rather than cover the sticky portion with more tapew, I opted to use denatured alcohol and clean it off. Made for a very smooth finish that hopefully would reflect sunlight. Unfortunately, it didn't.
 
Lessons learned from Do...

Test fit and experiment with everything well in advance of the build. The flat wire being still too thick hit me with about a week to go before the flight. My solution worked, but being time crunched and having the problem hit me well after most everything was finished limited my options.

Coast time can be rethought. I did not ose near as much speed as either sim suggested. This means I could probably handle adding time between separation and sustainer ignition.

The fins could be bigger, although coning was not an issue after it punched through Mach. It did get squirrely beforehand and that probably slowed it down.

Fire the separation charge from the booster. A couple reasons...More simplicity in the wiring. Two flat wires used to fire the sustainer would have fit inside the airframe.

Make sure there is enough room for your recovery equipment of choice. The rocket could have used an extra inch.

The engine paint worked well. I had some issues with loss around the fins, but overall, it seemed to be fine. It also sanded a lot smoother.

If I'm going to go higher, I need a lot better recovery equipment. GPS tracking, better receiver. tracking for the booster.

Add more coast time.


So moving on with Re, I will add the necessary electronics. It will be dual deploy, coming down drogueless. I also need to look at an alternative to BP for apogee separation because this rocket will be pushing 40,000'. Re will be moving much faster...Mach 2.5 or so. I am going to have to deal with more heat resistance. I tend to take a summer break from rocketry and fly again in the fall. Re will be the winter build project this year. I had a coule other rockets last year while I built Do, but I think I want to better manage my time with this one...if I can control myself.
 
Are you going to fly Do again? Should give it a shot, while adjusting parameters until you optimize your flight. At least motors for Do are cheap :)
 
Are you going to fly Do again? Should give it a shot, while adjusting parameters until you optimize your flight. At least motors for Do are cheap :)

No... "It was a successful mission."

Aside from using a pair of H255's which would get me 2 more NS and about 10 more feet, the real optimization would require a reconfiguration to separate the booster with a charge fired from a small accelerometer in the interstage coupler. That way I would need to only run two flat wires to ignite the sustainer instead of 3 to both ignite and separate.

Two flat wires would have fit inside and given me much cleaner aerodynamics. However, then I would have to peel the flat wire from the sustainer, clean out the solder that connected the wire coming from the AV Bay to the flay wire, refill those holes, then repaint the rocket...and if I'm going to repaint it, I would need to sand and smooth the surface again because of paint that chipped away from the fins.

I may as well do that with the next one instead of spend time doing it with this.

The real purpose of Do was to build and fly an extreme minimum diameter rocket and determine if a delayed ignition of the sustainer would work and gain altitude. That was accomplished. Plus, If you've ever been to Potter, you know that you have a good mile of field to recover...nice...but for a rocket that is not DD and needs the main chute to open at apogee, you're going to need a lot more than a mile to recover it. And once you get away from that nice open field, you have trees, cows, barns, silos, ravines, etc. that make finding it a real challenge.

I'm thinking that when I go to Black Rock to fly Mi, that I might resurrect Do and Re to fly as well, but not until then.
 
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