One day I came across Mach 1 Rocketry’s BT-50 Patriot Missile and was very curious about it. Here was a rocket that is inherently sturdy (fiberglass!) styled in a form that I really appreciate (I’ve always loved the Estes Patriot’s simple, 4FNC design). But it’s a smaller BT-50 size and therefore, can fly off of the A (maybe),B and C BP Estes engines I usually use.
Unfortunately, there was little information about this rocket, not even pictures of the kit or a finished specimen. So I reached out to Mach 1 Rocketry and they agreed to send me a BT-50 Patriot Missile kit for a nominal cost. In return, I would do a write up of my build, and here it is. NOTE: By the time I received this kit, Dave Thomas posted a really nice build video of this kit which I encourage you to watch if you’re interested in buying or building this kit.
I hope you enjoy the write up as much as I did building this rocket. The rocket is currently in the process of being painted and I’ll post pictures of the Patriot when the painting is done. Right now, the yellow is drying…
The above pictures show what you can expect when you get your kit. I believe the nose cone is the same one that comes with the Estes E2X Generic and Alpha, but I'm not 100% sure. The below picture shows the parts I used for the major modification of adding a baffle and reinforced dead space.
When I built the motor mount tube, I knew I wanted to also install a baffle. Ideally, I’d use a longer BT-20 tube to hold both the 18mm removable baffle and the 18mm engine. Because I didn’t have that, I decided to install a permanent baffle. Because it’s not removable, I added reinforcement to the dead space by lightly gluing in a BT-50 coupler that had been sanded down to save a little bit of weight and help it fit in the BT-50 tube more easily (I like to build heavy, but don’t like adding weight unless it serves a purpose).
Part of adding a reinforced dead space meant I needed to shift the top/front fiberglass centering ring to the upper tip/end of the fiberglass motor mount tube (MMT). This was necessary to maximize the dead space volume while still preventing ejection gasses from having direct contact with the main body tube at the point just above the MMT (something I like to avoid in my cardboard LPR builds, although probably not necessary in a fiberglass rocket…). This led to a problem where I no longer had the fiberglass centering ring in the right location to help hold down the metal engine hook. So I took part of a 24mm BP Estes engine and added it to the MMT so it has 3 centering rings (even though only 2 of them actually do any centering).
Because I was going to use a permanently installed baffle, I went with a 24mm one instead of an 18mm one.
Here's what everything looks like when installed.
The kit comes with a nice thin-mil Nylon parachute from Top Flight Recovery LLC. It’s 9” in diameter, which would be a bit small for a rocket of this weight…if it were made of wood and cardboard! I added the metal ring and snap swivel; those weren't included in the kit.
Here's how I attached the launch lug. I went ahead and use a 1/8" one instead of the one included with the kit as I don't have a 3/16" launch rod and I planned on launching this with no more than a C engine. I'm only posting a picture here to show how I aligned the launch lug and how you can use a sander to confirm it's properly positioned.
Now we’re getting to the “new” stuff for me, namely using epoxy to glue in fiber glass fins. Not much to do here besides post the pictures. I will note that I still have much to learn about filleting with epoxy, as after I removed the masking tape, I noticed that there was a bit of a “ridge” where the epoxy met the masking tape edge. I tried to reduce this by removing the masking tape before the epoxy fully cured, but I think I waited too long, as the ridges were very evident.
Once the fins were done, I completed the recovery system. Yes, I’m still using the parachute protector that came with the kit because it’ll help keep the parachute clean from a little bit of non-damaging bits that come through the baffle.
And here’s what the rocket looks like when it’s mostly done being built. The parachute wasn’t inside the rocket in this picture, but besides that, this rocket is ready to fly.
As mentioned earlier, I’ll post more update pictures once the painting is done.
As for my overall impressions, this is a great, high-quality kit with top-notch components and parts. And the fiberglass...it...is...niiiiiiiiiice!
The only things I didn't like about the kit had nothing to do with the kit, but rather, the precautions you have to take when working with fiberglass and epoxy (wearing gloves and a mask when sanding fiberglass, wearing gloves when working with epoxy, working outside when sanding fiberglass, etc.).
I have yet to fly this rocket, but I'm confident it'll perform well. I might need to add some weight to the nose cone, although my simulations in Open Rocket say that's not necessary. We shall see...
Unfortunately, there was little information about this rocket, not even pictures of the kit or a finished specimen. So I reached out to Mach 1 Rocketry and they agreed to send me a BT-50 Patriot Missile kit for a nominal cost. In return, I would do a write up of my build, and here it is. NOTE: By the time I received this kit, Dave Thomas posted a really nice build video of this kit which I encourage you to watch if you’re interested in buying or building this kit.
I hope you enjoy the write up as much as I did building this rocket. The rocket is currently in the process of being painted and I’ll post pictures of the Patriot when the painting is done. Right now, the yellow is drying…
The above pictures show what you can expect when you get your kit. I believe the nose cone is the same one that comes with the Estes E2X Generic and Alpha, but I'm not 100% sure. The below picture shows the parts I used for the major modification of adding a baffle and reinforced dead space.
When I built the motor mount tube, I knew I wanted to also install a baffle. Ideally, I’d use a longer BT-20 tube to hold both the 18mm removable baffle and the 18mm engine. Because I didn’t have that, I decided to install a permanent baffle. Because it’s not removable, I added reinforcement to the dead space by lightly gluing in a BT-50 coupler that had been sanded down to save a little bit of weight and help it fit in the BT-50 tube more easily (I like to build heavy, but don’t like adding weight unless it serves a purpose).
Part of adding a reinforced dead space meant I needed to shift the top/front fiberglass centering ring to the upper tip/end of the fiberglass motor mount tube (MMT). This was necessary to maximize the dead space volume while still preventing ejection gasses from having direct contact with the main body tube at the point just above the MMT (something I like to avoid in my cardboard LPR builds, although probably not necessary in a fiberglass rocket…). This led to a problem where I no longer had the fiberglass centering ring in the right location to help hold down the metal engine hook. So I took part of a 24mm BP Estes engine and added it to the MMT so it has 3 centering rings (even though only 2 of them actually do any centering).
Because I was going to use a permanently installed baffle, I went with a 24mm one instead of an 18mm one.
Here's what everything looks like when installed.
The kit comes with a nice thin-mil Nylon parachute from Top Flight Recovery LLC. It’s 9” in diameter, which would be a bit small for a rocket of this weight…if it were made of wood and cardboard! I added the metal ring and snap swivel; those weren't included in the kit.
Here's how I attached the launch lug. I went ahead and use a 1/8" one instead of the one included with the kit as I don't have a 3/16" launch rod and I planned on launching this with no more than a C engine. I'm only posting a picture here to show how I aligned the launch lug and how you can use a sander to confirm it's properly positioned.
Now we’re getting to the “new” stuff for me, namely using epoxy to glue in fiber glass fins. Not much to do here besides post the pictures. I will note that I still have much to learn about filleting with epoxy, as after I removed the masking tape, I noticed that there was a bit of a “ridge” where the epoxy met the masking tape edge. I tried to reduce this by removing the masking tape before the epoxy fully cured, but I think I waited too long, as the ridges were very evident.
Once the fins were done, I completed the recovery system. Yes, I’m still using the parachute protector that came with the kit because it’ll help keep the parachute clean from a little bit of non-damaging bits that come through the baffle.
And here’s what the rocket looks like when it’s mostly done being built. The parachute wasn’t inside the rocket in this picture, but besides that, this rocket is ready to fly.
As mentioned earlier, I’ll post more update pictures once the painting is done.
As for my overall impressions, this is a great, high-quality kit with top-notch components and parts. And the fiberglass...it...is...niiiiiiiiiice!
The only things I didn't like about the kit had nothing to do with the kit, but rather, the precautions you have to take when working with fiberglass and epoxy (wearing gloves and a mask when sanding fiberglass, wearing gloves when working with epoxy, working outside when sanding fiberglass, etc.).
I have yet to fly this rocket, but I'm confident it'll perform well. I might need to add some weight to the nose cone, although my simulations in Open Rocket say that's not necessary. We shall see...
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