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High Speed Rocket (X1)

Here’s some more info about the X1 rocket from my video from the end of last summer.

If you’ve not already, check out the video here!

This build is all about a high performance model rocket constructed using PVC pipes, 3d printed parts and a large solid fuel motor

I designed this rocket mainly using CAD and manufactured many of the parts from scratch.

I’ve built lots of rockets before but this time I made it dead simple to hopefully show you how you could make a high speed rocket from commonly available materials like this plastic plumbing tube and bits of plywood and stuff like that.

I designed this rocket to small and slippery. High speed vehicles need to be as small as possible to displace as little air as possible. This is why high speed RC aircraft are all as small as possible. As the mission of this rocket was to go faster than anything I’d built before, the X1 was therefore designed to have a very small frontal diameter meaning in will push through less air, have less drag, and be faster than any than many of my previous rockets.

The CAD program for simulations I used is called Open Rocket. I used it to figure out the speed and altitude of different designs by assembling body tubes and nose cones that have drag coefficients and mass. It’s super helpful as you can see how stable your rocket will be and how high it will perform using various motors. The motor I decided to use was a Cesaroni ‘G’ motor with a burn time of around 3 seconds. This engine provides 12.1kg of max thrust and it’s one of the biggest I can buy from a hobby shop online without being certified and doing a qualification. I predicted that this motor the rocket should accelerate to 730kph and top out at just over 840m up, over 100m clear of the maximum hight you can launch rockets in the UK. Here’s some info on UK model rocket laws if you want to get started with model rockets in the United Kingdom.

Building the Model Rocket

As usual I designed parts like the nose on Fusion 360, which has a free licence for hobbyists, before printing them on my 3D printers. Fins were cut from thin sheets of plywood on a laser cutter – I know, not everyone has access to one of these fancy things but you could cut fins by hand. The fins pushed into slots in the fuselage PVC tube, which is just a bit of old plumbing I found lying around, and then, yeah, everything was epoxied together.

Why did I add extra fins?

The finishing touch was to add a coat of bright orange paint. As this is the start of my ‘X’ program of highly experimental rockets, rocket planes and other vehicles, I thought I should take some inspiration from the real X1 flown by Chuck Yeager.

Launch Rail

This launch rail setup is new but I’m still working on refining this setup. I’ve been using the same 2020 aluminium extrusions to launch model rockets for over a year, now but they needed a proper base that’s easily adjustable for sloping hillsides and that sort of thing. For this reason I made an attachment for my favorite tripod which can be quickly adjusted at the launch site.

I’ve also been working on a safer and more refined electronics setup for launching larger, higher powered rockets. Essentially all you need to do to launch the rocket is pass some current through the electronic igniter, so up until now I’ve simply had a controller with a couple of switches that connect the rocket’s igniter to a LiPo battery (the same as I use to fly my airplanes). To move further away, much further away, I’ve combined the launch controller with my RC controller.

The Remote Ignition Switch

The RC controller is as simple as a brushed ESC connected to the throttle channel of my DX9 RC transmitter. The motor wires from the brushed ESC are connected to the igniter. This way, increasing throttle on the transmitter will pass current from the battery directly into the igniter. Now I can retreat all the way back to safety, arm the throttle channel and fire with a programmed switch on the DX9! Straightforward, reliable and effective.

Why Not Use a GPS onboard the rocket?

I’d been thinking it would be a good idea to add a GPS to get some accurate data from the flight. This worked quite well in my High Power Rocket Plane V1.

Now, here’s the thing: my previous GPS was destroyed by the recent rocket car fire so i’ve had to get creative with a replacement. I was thinking about building a GPS with an Arduino, as I’ve seen other people do, but I’d realised I have a GPS already that might do the job!

I have a GPS watch, so I thought I should be able to get some decent data from this, right? Sure, it will only capture data points once every second and be a bit limited, but I should be able to export the GPX files to Google Earth and have a cool overlay of the flight path.

I had the great idea of testing this out by strapping the pod under an RC Spitfire and taking it up on one day during an extremely windy day. Essentially, what I was trying to do was fly around in three dimensions to try and make a 3d path that I could then display on Google Maps, showing my flight path. Unfortunately, the flight didn’t end well. At least I had some good data, right? Well, no. It turned out I’d sacrificed the plane only to find out the watch simply recorded an X and Y and calculated altitude based on ground based position – which was extremely annoying to find out at the last minute.

Only X and Y, X and Y!

I need to come up with a better solution for the future, but for now I have no GPS, unfortunately.

If you’re wondering why I didn’t have a GPS tracker onboard, I’m afraid I couldn’t find one small enough for this rocket so used a Bluetooth tile which – yeah – are useless really. I would recommend them for finding your keys, but not for finding a rocket that could land 500m from the launch site when the range of the tile is but 40m!

X Series Naming System

So, this is the first vehicle of mine I’m naming with my new organizational system to help you and I keep track of these vehicles I make. I’ll be numbering each of them with the prefix meaning experimental. As this one is the first, appropriately seeing as though it’s orange, it’s called the ‘X1’. Hopefully you like the idea.

Concluding thoughts

I hope you enjoyed this one! Make sure to keep a look out for flight 2 of this rocket this spring (2022) when the weather improves.

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