1/2 scale PML Patriot build

So, for now I put the RamJet away for now and will get back to it when I finish this build.
I started with the upper payload bay by fiberglassing it with one wrap of 8.5oz.
I got all the parts for the motor mount and started that next. Here are a few pics of what I did so far.

Got the holes drilled for the motor retainer


Got the retainer on with motor case

All the parts for the MM, for got to include the U bolts

Marking spots to drill


Taped the CR together and start drilling the holes


Time to dry fit everything, is this overkill for the recovery system?
Next I'll be glassing the main body tube, all four feet of it:tongue:

Who is anyone to say if its a over build. Its your rocket so you can build it like you want. I guess I am a over builder myself, but than again I have not had one come a part yet.

Looks like good work so far.

A couple of questions. What is the MMT diameter? At 1/2 scale that should be a 8" diameter BT so that looks like 54mm MMT? Why the four threaded rods? Would a longer MMT (to accommodate a CTI 6GXL case) with a extra CR be lighter then the threaded rods and hardware? Or at least put the weight more forward? That would also prevent the motor casing from getting damaged by the recovery harness and any quick links used.

Those are my thoughts, can you let us know why you made the choices you did? I'm always up for learning more.

Thanks...

Handeman said:

Looks like good work so far.

A couple of questions. What is the MMT diameter? At 1/2 scale that should be a 8" diameter BT so that looks like 54mm MMT? Why the four threaded rods? Would a longer MMT (to accommodate a CTI 6GXL case) with a extra CR be lighter then the threaded rods and hardware? Or at least put the weight more forward? That would also prevent the motor casing from getting damaged by the recovery harness and any quick links used.

Those are my thoughts, can you let us know why you made the choices you did? I'm always up for learning more.

Thanks...

Click to expand...

Thanks, now to answer your questions. Yes it's a 54mm motor tube, your right it should be 8" dia but PML sells it at 7.5" dia, as for the four threaded rods, I wanted a more solid attachment point for the recovery harness as this will be a big and heavy rocket and I don't want the recovery to fail, I've seen people do this in bigger L3 rockets and wanted to try it myself.

I would of put a 3" motor mount in it. This way you can adapt down, and fly a full L then a M when your L3.

I got a lot done today, first I got the main body tube glassed then I got started on glueing the motor mount together, it took a lot of epoxy to fiberglass the body tube

Got all the stuff to start fiberglassing

Fiberglass done and peel ply on


I'm using Aeropoxy for the motor tube and rings

jus_rockets said:

I would of put a 3" motor mount in it. This way you can adapt down, and fly a full L then a M when your L3.

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I really wanted to put in a 3" MMT so I could use L motors, but with a limited budget, 3 kids a wife and a mortgage I just can not afford to upgrade to a 3" MMT:sad:

With a 3" motor mount you can always adapt down but, you took away that option.


JD

Kehoes23 said:

I really wanted to put in a 3" MMT so I could use L motors, but with a limited budget, 3 kids a wife and a mortgage I just can not afford to upgrade to a 3" MMT:sad:

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There are plenty of spunky 54mm motors that will provide beautiful, majestic flights for a rocket like this. AT K1100 or K1050. Many CTI choices. My L2 cert back in '96 was a 7.5" patriot (LOC tubing) on a K550.

JDcluster said:

With a 3" motor mount you can always adapt down but, you took away that option.


JD

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I still have the option to put in a 3" MMT, since I'm only putting it together and have not epoxied it in the main body tube yet, like I said in the previous post I can not afford to buy the parts for the 3" motor mount, but if you have the parts for a 3" MMT I would gladly take it and put that in instead of the 54mm MMT.:handshake:

You may be a rocket geek if you’re constantly being pulled over by law enforcement for having a ½ scale Patriot Missile strapped to the top of your Ford Fiesta.

You may be a rocket geek if your ½ scale Patriot Missile costs more than the Ford Fiesta upon whose roof it is strapped.

You may be a rocket geek if the motor for the ½ scale Patriot Missile produces more power than the engine of your Ford Fiesta.

And you may be a rocket geek if you actually know a formula for converting and comparing the two.

Good luck with the build; take lots of pictures when it flies.

On my 1/2 scale Patriot I went with a 98mm MM, adapted down to54mm. Flown on K550 low and slow, K1100 fast lift, about 2000 ft. (wieghs 35 lbs). I removed the piston and made it dual deploy. Warning, I didn't have enough room for the class 3 chute so I added 24" to the top. used a fiberglass sock to glass it, worked great. I like the U bolts, I used 2 eye bolts and they streched last flight, don't know how I'm going to get in there to fix them. Great rocket, just have a friend help you carry it to the pad and, oh yeah, help you retrieve it.

:rofl::rofl::rofl::rofl:

boomtube said:

You may be a rocket geek if you’re constantly being pulled over by law enforcement for having a ½ scale Patriot Missile strapped to the top of your Ford Fiesta.

You may be a rocket geek if your ½ scale Patriot Missile costs more than the Ford Fiesta upon whose roof it is strapped.

You may be a rocket geek if the motor for the ½ scale Patriot Missile produces more power than the engine of your Ford Fiesta.

And you may be a rocket geek if you actually know a formula for converting and comparing the two.

Good luck with the build; take lots of pictures when it flies.

Click to expand...

:rofl::rofl::rofl::rofl:

cobra1336 said:

On my 1/2 scale Patriot I went with a 98mm MM, adapted down to54mm. Flown on K550 low and slow, K1100 fast lift, about 2000 ft. (wieghs 35 lbs). I removed the piston and made it dual deploy. Warning, I didn't have enough room for the class 3 chute so I added 24" to the top. used a fiberglass sock to glass it, worked great. I like the U bolts, I used 2 eye bolts and they streched last flight, don't know how I'm going to get in there to fix them. Great rocket, just have a friend help you carry it to the pad and, oh yeah, help you retrieve it.

Click to expand...

Do you have pics of the 1/2 scale Patriot? Would you happen to know the approximate CP location? How much weight did you use in the nose cone?

I'll try later at home. Working long days now.

I finished getting the motor mount glued together and ready to glue inside the main body tube, I left the aft and forward CR unglued so I can do fillets on the middle CR and internal fillets on the fins.:caffeine:

I'm starting to think my 5.5" patriot with the 3" MMT is scary... Seriously though - looking forward to seeing this all together.

HaackIt said:

I'm starting to think my 5.5" patriot with the 3" MMT is scary... Seriously though - looking forward to seeing this all together.

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https://www.rocketryforum.com/showthread.php?53991-L3-5-5-quot-Patriot-from-scratch&highlight=5.5+patriot+l3

Nice! How much did yours end up weighing? I wasn't exactly scratch, but my kit was designed for a 54mm motor so it had a lot of beefing up to do.

HaackIt said:

Nice! How much did yours end up weighing? I wasn't exactly scratch, but my kit was designed for a 54mm motor so it had a lot of beefing up to do.

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Sorry - re-read - see ~25lb.

I drilled holes for internal fillets of the motor mount and center CR

The MMT is inside the body with the fins taped on, I do it this way so when the MMT is glued in, it will be a perfect fit for the fins.

That's a far reach to the center CR, getting ready to add some Aeropoxy


I had to stand on a chair to reach the center CR to apply the Aeropoxy

It even looks big when not put together.
Should I do traditional paint, (red,black,white and yellow)? Or do something different? Either way, it's going to take lots of paint.

I'm getting ready to do the body work on the payload section, which would be better to use to fill in the pinholes? Elmer's wood filler or bondo? Thanks for your advice

Kehoes23 said:

I'm getting ready to do the body work on the payload section, which would be better to use to fill in the pinholes? Elmer's wood filler or bondo? Thanks for your advice

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Although both may work, Bondo is designed for a fiberglass/epoxy base and would be a better choice. Even better would be a lightweight epoxy-based filler like SuperFil or QuickFair.

dixontj93060 said:

Although both may work, Bondo is designed for a fiberglass/epoxy base and would be a better choice. Even better would be a lightweight epoxy-based filler like SuperFil or QuickFair.

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Thanks for the info, what would be the best place to get the superfil/quick fair?

After a little elbow grease I finally got the forward CR on

And some more Aeropoxy to hold it in.

One other thing that I worked on was the bulkheads for the avebay, I also decided to fiberglass the bulkheads, I just wanted to add some more strength for the recovery attachment point.

Kehoes23 said:

Do you have pics of the 1/2 scale Patriot? Would you happen to know the approximate CP location? How much weight did you use in the nose cone?

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Per the PML Website Kit Specification Chart pdf it is 73" from the tip of the nose cone.

Kehoes23 said:

Thanks, now to answer your questions. Yes it's a 54mm motor tube, your right it should be 8" dia but PML sells it at 7.5" dia, as for the four threaded rods, I wanted a more solid attachment point for the recovery harness as this will be a big and heavy rocket and I don't want the recovery to fail, I've seen people do this in bigger L3 rockets and wanted to try it myself.

Click to expand...

I understand your desire to have a strong point to attach your recovery harness. Yes many folks do add the threaded rod for L3 rockets but the 75 and 98 mm motors are much heavier than 54mm motors. IMO the 4 lengths of rod and hardware will add extra weight to the end of the rocket that needs it the least.
The following suggestions are for future builds. I am not certain of the size rod you used but it looks like 5/16", two lengths of 1/4-20 would have been sufficient especially if you ran them through the middle of the u bolts and used fender washers on the aft end. An alternative would have been to used no rod, but glue in a 6" section of tube coupler in front of the fwd centering ring. This would add little weight and it would be almost impossible to pull the ring out.
I try to build rockets as light as safely possible.
More weight will require larger/stronger recovery gear which in turn adds more weight. It can be a vicious circle.
Good luck on your flights

Sailorbill said:

Per the PML Website Kit Specification Chart pdf it is 73" from the tip of the nose cone.

Click to expand...

Thanks for the info.