|Date:||27th August 2022|
|Conditions:||light wind ~5km/h, mostly sunny|
Conditions on this day were near perfect. Very low wind, mostly sunny skies, and launch area clear of crop stubble.
For our first flight we wanted to test the Horizon prototype deployment mechanism that we built a week earlier. We mostly wanted to see if we can eject the 60" parachute sideways from an 80mm air frame. The setup was very similar to what we use normally on our water rockets. We also wanted to attach the parachute the same way we would attach it to the booster so that it would come down sideways. The rocket we decided to test it with was a 10 year old fiberglass rocket. - Polaron G2b. This is similar in length to the booster but slightly wider.
The rocket was filled with 3.8L of water and because we are using a launch tube decided not to use any foam. The rocket took off well and flew nice and straight to apogee. From video we can see that the parachute was ejected cleanly and the canopy fully opened about 1 second after deployment.
The rocket was very stable under parachute and gently landed about 300m away from the launch site. The slight breeze then proceeded to drag the rocket for another 1km until it got caught on a barbed wire fence next to the road. The rocket was all scratched up and dirty, but managed to survive well.
We also flew Daniel's Rokit flight computer along on this ride to measure altitude and see what kind of G-forces were applied to the air frame when the parachute had deployed. This was around -6.5G. We also wanted to see the descent rate the parachute achieved with this weight and rocket orientation. The descent rate was 2.35m/s or 7.7fps. Maximum altitude was 214m (702 feet). Deployment was set to 7 seconds. The parachute was fully inflated at 8.9 seconds.
Here are some photos from the day.
For the next flight we wanted to re-fly the Nova rocket that has crashed on the last two attempts. On the last two attempts the parachute had not deployed and we weren't exactly sure why that was. We suspected that the lack of an ejection force and the airflow over the nosecone was keeping the door pressed up against the parachute and not deploying it.
So this time around we added a small corriflute ejection plate with a couple of rubber bands.
We filled the rocket up with 700mL of water and foam and attempted to launch it at 300psi. When dad pressed the button the rocket did not take off. At first we thought maybe the launcher had failed, but when approaching the rocket we noticed that the launcher had deployed, but the rocket was wedged on the launcher. This was a little weird as we never had that problem before with this rocket. We depressurised it and took it back to the work table. I was suspecting some dirt or sand was wedging the rocket in place, so we washed out the rocket, but this did not help. The rocket was sliding onto the launcher fairly easily, but just wouldn't come off when trying to pull on it again. We ended up rotating the rocket 120 degrees, and this solved the problem of being able to slide off easily. The rocket must not be completely symmetric.
We filled the rocket up again and set it up on the pad. This time the rocket released cleanly and made a beautiful foam trail almost all the way up to apogee. The parachute opened this time and the rocket landed safely. Although on landing the 3D printed nosecone broke again when it hit the ground. I think this is caused by the weak PLA we were using that had quite poor interlayer bonding. There are also only 3 screws holding it together and so these become the stress points. When we printed this nosecone we also doubled the wall thickness from the previous one, but it still wasn't strong enough.
We decided to glue and tape the nosecone back together and try for another flight. The setup was identical and we again launched the rocket at 300psi. The parachute again opened around apogee and the rocket landed safely, and again the nosecone broke a little more.
But it looks like the fix we did to the deployment mechanism worked well and the parachute deployed cleanly this time. The Nova STL files are now available for download.
Over the last 6 months we've noticed our video camera that we've been using for most of our filming has started mis-behaving. The optical stabilizer now produces shaky video when holding the camera by hand, and if we use the automatic shutter speed, in sunny conditions, the video comes out blurry. We can set the shutter speed to something like 1/500th and then it is fine. But we have to remember to do this, because you can't see the slight blur on the screen. Also a couple of times now a video file was corrupted, but I am not sure if it was the camera or the SD card. With these issues, we decided it was time for an upgrade. We ended up purchasing the Panasonic HC-X1500 camera. It is more of prosumer camera with a lot more options, and better quality recording. It will do up to 60fps at 4K. It has a lot more manual controls to get even more out of the camera. So far we are quite happy with the camera and the footage it produces.
We will still use the old camera on a tripod because it still produces good video that way.
Overall it was a very good weekend with lots of interesting rockets going up. There were well over 100 people at the launch site, with 4 universities represented USYD, UNSW, UTS and ANU.