1/4 Scale Viking 7 sounding rocket

[GalantVR41062]

I have flown the rocket 3 times, it is not completed but more of a work in progress.

I can put a update together on the 3 flights with flight data, pictures and video.


Motor: Aerotech L1000w su 54mm.
August 14 2021



Motor: Aerotech L1256WS-p 75mm.
July 9th 2022


Motor: Aerotech L1365M 75mm
September 11th 2022.

 

[GalantVR41062]

Test flight

Motor: Aerotech L1000w su 54mm.
August 14 2021

Altitude: 1,119'
Max velocity: 252.4 ft/s
Landed on drogue at 25ft/s in a ditch.

View attachment 20210814_155256_001_001.mp4

I worked on the coupler body tube fit and finish to help the sag I was seeing in my ground testing. I used clear packing tape as a final layer for the ebay into the booster and nose cone into the payload.



For the test flight I did not have shear pins in the nose cone. The nose did pop out as the over sized drouge took air and slowed things down at apogee 1,119' above the sod farm.

The main was a tight fit into the deployment bag and remained stuck, this is the reason it landed on drogue. The rocket was not damaged and it landed in a wet ditch and received some natural brown paint on the booster.



I have been using the frame strapped to the trailer for transport, and using the frame to bring the rocket out to the away cell and back from the LZ. We do get some interesting looks on our 1hr 15min drive to and from the launch site.

I downloaded the ARTS2 data and have the CD, motor burn profile and flight summary. I have been tweeking the OR simulation files after the flights to hone in the details and flight profiles.









For the test flight I had time to lay fillets and paint the nose cone yellow. I had a old sled (from my L2 rocket) and twist and tape on the electronics.





I do not have any specific photos but I did have to get a little creative adapting down from 98mm to the single use 54mm AT L1000w-18. I plan to fly this project on 75mm/98mm from now on.

 

[GalantVR41062]

Motor: Aerotech L1256WS-p 75mm.
July 9th 2022

Altitude: 1,900'
Max velocity: 340 ft/s
Landed in mess in the middle of the field. The main chute was fouled by the payload tube but landed with no damage.
We added a buddy being deployed with the main, paratrooper Snoopy.

I did plan to fly the rocket again in late 2021 but due to a anomaly during prepping the rocket I decided to shelf the project for the fall/winter. I came back to it in the spring with a plan to paint the rocket like a Minion, blue bottom with 2 black fins, black switch band and yellow top. My daughter loves the minions, and this was decided and painted just before the world was on high alert and Ukraine was invaded by Russia. I came to find out the Ukraine flag is Blue and Yellow. As of now the rocket is still painted this way. I do plan to work on filling the spirals and making a go of the actual sounding rocket paint job as I already have the material.

I decided to check the separation charges again after the paint job. I did up the charge size a little from the test flight.



We also decided on adding Snoopy our paratrooper with the main parachute. He drifts nice and vertical on a well used 24" PS2 chute.




I had assembled the motor in 2021 so before heading up to the launch site I inspected the motor and re-lubricated the o rings. The amazing Aerotech L1256WS roared to life and lifted the "Minion" skyward to a apogee of just over 1,900 feet. I was able to again download the data off the ARTS2 and simulate drag and thrust curve for the motor. I had the sled more secure this launch and a very clean accurate looking thrust curve was plotted.



After the test flight I reworked the recovery gear and recovery plan a little. I picked up a smaller drogue chute, it was a Rocketman Pro experimental drogue 7 foot. I noticed the decent rate was still a little slow and resulted in a almost vertical payload tube. It was rotating in a cone shape and when the main charge fired the nose cone was almost pointed too the booster and everything came straight down and the payload tube landed on the canopy of the main before it full inflated.



The rocket landed on the field with a thud, no structural damage to the rocket.

The boost was nice and straight, I did not have anything for fin tabs sorted for this flight so it was not a true scale Viking 7 sounding rocket yet.



So the Ebay for this project has been a struggle and one that almost caused me some major harm. I mentioned a anomaly during prep, here it is. I had my Ebay on the toolbox in my garage, with recovery harnesses hanging off both ends. I had the sled with altimeters installed, the batteries had twist and tape wires setup going to each altimeter, the wires were out of the switch band with a clean cut, no stripped wires folded away from each other and electrical tapped. I had the ematches hooked up directly to the altimeters and in the charge well cups, I have sense moved to twist and tape on one leg of the ematches for all 4 charges.

As I was prepping the deployment charges I had measured out the black powder and was putting it in the charge wells, covering and taping. As I moved the ebay from the drogue side to main I started to hear a very faint beeping from inside the ebay, very faint. I have tinnitus in my ears and took some focusing to hear what was happening. So after tapping up the main charge I came to realize the situation I was in. I thank God the charge did not go off in my face, I had just started to make an exit plan and rotated the ebay as the drogue charge went off, it was pointed downish and across my chest.

As that happened I thought about reading when altimeters miss fire, normally the drogue first then the main.... that was pointed up and about 10" from my face.... I managed to toss the ebay away from me onto my toolbox as the main charge fired pointed at the wall. The garage doors were closed and I ended up with burned eye brows and arm hair and very shaken up by the entire ordeal.

I opened the garage, made sure there were no more fires and dusted my self off. After returning from the launch that day I tried to be methodical in how this happened. I tried everything I could think of and could not get the altimeter to receive power enough to start beeping slightly but not fully turn on. I did determine this was the older MW rrcx2.

 

[GalantVR41062]

Motor: Aerotech L1365M 75mm
September 11th 2022.

Altitude: 2,660'
Max velocity: 408.37 ft/s
Landed under main for a almost perfect nominal flight.



After some trials here it is all hanging under the main chute. I think I calculated the rocket to be around 86 feet from the top of the main to the bottom of the booster. It was an exciting site to see.

I worked on finishing the scale details of the air foiled fin tabs for this flight. I picked up some nylon 1/4-20 screws and cut and belt sanded the shape onto the wood to make the fin tab. I then drilled 2 holes up into the tab, threaded the screw into fin then after painting epoxied the fin tab onto the nylon screws. These are only for the visual look, they do change the CP a little but for smaller motors the stability margin is good with and with out them.

The plan is for the tabs to be a 1 time use, fix as needed, 2 were damaged on landing (The fins are doing great so these tabs being one time use is fine).



I also picked up a AT 98/5120 motor and the full L1500T for the next flight of this project. If the conditions are favorable the rocket could go over 3,000' in altitude. The AT 75mm L2200G will be a more energetic launch but I am looking forward to the 3.5 second burn.



I worked hard on the Ebay from the previous flight. I have continued twist and tape on 1 side of the 4 ematches and reworked the electronics to use 2 wifi switches to turn on the altimeters. I tested things on the bench, in the Ebay before energetics were secured but still something came up on the field. We had made our way out to the away cell and after getting the rocket loaded onto the rail I started to hear the faint noise from the newer MW rrc2+. I tried to connect to the wifi switch for the rrc2+ and it showed up for a split second then nothing, but the altimeter was still making that faint noise.

I almost scrubbed the launch at this point. I decided if I could connect and arm the other set of electronics I could still fly the rocket. I would be lying if I said I did not have some outside pressure, I had family that drove up to see the project fly, my Dad was with and besides flying small rockets at the parks this was his first high power launch.

I was able to connect, arm and hear the proper noise from the other altimeter. This was also the ARTS2 with 200hz sampling to make the motor thrust curve etc.



I was amazed as I reviewed the pictures, video and flight data. The motor burn was good, with a energetic spike at 0.25s into the burn. It came up as a 91.6% L motor.

I was not sure if the thrust curve spike was accurate so I started to view the video frame by frame. I noticed something as the rocket left the rail, about 0.25s into the flight. I saw a shock wave propagating past the rocket.

After a few attempts with screen shots I captured the shock wave on the way up. I need to upload the video to Youtube or something as the file size is to big to upload directly onto forum.



I am not sure what I am going to do about the ebay but I have a little less then 1 month to figure that out and possibly work on the proper paint scheme for this project. The weather and Life has made flying rockets tricky this season.