PML Patriot 4" Build Thread

[Quaranta]

Some of you may be following my Sirius Sat V Build thread. As that nears completion, I need to get my level 1 in order to fly her...

For Level 1: I have chosen the PML 4" Patriot w/ 38 mm MMT.

Why? It's a nice size for level 1. I'm going to build her engine deploy,... but she comes with a 12" payload bay, so I can mod her for dual deploy later if I ever get the urge.

I'll build her close to stock, except I don't care for Piston eject systems, so I'll add an eyebolt and have a traditional recovery arrangement. Launch rail lugs will be used instead of the brass tube lugs. I'm going to attach the NC to the PB with 4 machine screws for now...

Paint will not be one of the 2 common Patriot paint schemes, but will be military themed.

Here are the relevant parts. The kit also comes with the piston h/w, a 48" chute, nylon cord, and brass lugs (not shown).

[Aksrockets]

Sounds like a good plan. The patriot seems like a perfect kit for a L1 cert.
Remember to get that quantum tube nice and rough!

Alex

[Quaranta]

Sounds like a good plan. The patriot seems like a perfect kit for a L1 cert.
Remember to get that quantum tube nice and rough!

Alex

Good advice. I use a segment of belt sander belt to rough the tubes. Very tough and abrasive. Works great. I've built 1 other QT rocket (PML AGM PitBull).

[Quaranta]

Here's the 38 mm MMT. Marks at the rear of the tube are for the CR and an AeroPack MRS.

In some pics you will see blue painters tape. I use painters tape to hold the CR's level as epoxy sets. I then remove the tape and add fillets.

Fwd CR has been marked the drilled for welded eyebolt. (I'll have to dig out some washers from my tool box).

[Quaranta]

Forward CR attached.
Notch for the piston cord filled with balsa / epoxy.
Fillets added fwd /aft of CR.
Eyebolt attached with washers either side.

(painters tape now at rear of MMT to align aft CR to MMT while bonding MMT to main BT.)

[CarVac]

What's wrong with pistons? What are the "traditional" methods you speak of? (my school's rocketry class uses PML 2" rockets and the pistons work great every time and you can use miniscule amounts of black powder so as to not burn the shock cord)

[Quaranta]

What's wrong with pistons? What are the "traditional" methods you speak of? (my school's rocketry class uses PML 2" rockets and the pistons work great every time and you can use miniscule amounts of black powder so as to not burn the shock cord)

I never said there is anything wrong with pistons. I said I don't care for them.

As for what I consider a traditional recovery arrangement: eyebolt in CR; shock cord to nose cone; parachute attach to shock cord just aft of nosecone.

[Quaranta]

Fwd CR / MMT epoxied in BT. (I use 30 min epoxy, to allow a little time to get position just right).

The Aft CR is not epoxied yet,... just fit for alignment. Will be removed to add fillets to Fwd CR and fins prior to finally being epoxied in place. If you look close, there a 4 scotch tape tabs to pull it out...

The mark on the MMT (in Pic #2) aligns with the eyebolt. (this is important to place between fins to avoid interference between fin tangs and the base of the eyebolt)

[CarVac]

Are you going to use a PML HAMR for retention or do you have something else in mind?

[Quaranta]

I'm using AeroPack 38mm MRS. I've used AeroPack MRS on all my MPR/and now 2 HPR rockets.

I like them, and they look very professional / engineered. That said, I've never used anything else.

[sodmeister]

Another great choice for a rocket and your level 1.How do I know ,well i built one of course ,and it flies great and is quite a tough bird when built properly (just the way you are doing it )

I built mine very much like what you are doing ,almost exactly as a matter of fact.

Used machine screws and drilled & tapped the nosecone to the payload ,ditched the piston ,did not use those silly brass tubes but instead used rail buttons.I did however use the PML HAMR retainer (could not get the Aeropack in time) but it is pretty much the same as the AP ,except it has a small flange where it meets the aft CR.

Next to fiberglass ,you sure can`t beat painting Quantum tube ,can you !

Take care

Paul T

[Quaranta]

Thanks Paul.

I think the paint scheme I have in mind will look familiar to you. Your "Little John" was my inspiration.

[Quaranta]

Bulkhead epoxied into Payload section coupler.

[Quaranta]

Fins sanded and epoxied.

The aft CR is still only friction fit (if you look close, scotch tape tabs are visible to allow removal). Fillets are next... internal and external at BT, as well as at MMT.

[Quaranta]

Taped in preparation for the external fillets...

[Quaranta]

External fillets applied.

West Systems Epoxy-105, slow hardener-206, colloidal silica - 406.

I leave the tape on until after sanding. Serves as guide during sanding.

[Quaranta]

For internal fillets,... I use the same West Systems thickened epoxy.

I use a 60 CC syringe with refrigerator tubing to apply a bead. I then use a dowel with cardboard spatula tip to create the fillet / remove excess epoxy.

No points for beauty,... but quick, easy, and strong.

[Quaranta]

The Nosecone is being attached to the the Payload Tube with 4 stainless 4-40 machine screws. Plastic washers at the external surface. Nuts epoxied to the inner surface of the nose cone.

To position screws evenly I wrap grid paper around the Payload tube,... count the squares (51),... divide by 4, and mark for drilling. The grid paper also marks the long axis... very easy to evenly space screws etc this way.

To bond the nuts,... I used 30 min epoxy, thickened with west 406 colloidal silica. I run the machine screws through the NC,... attach the nuts,.. tape off the extra screw,... and apply a bead of thickened epoxy around the nut.

[Quaranta]

Bonded the coupler to the aft end of the PL tube.

Forward section of the rocket assembled and complete.

[sodmeister]

Nope ,at times internal fillets are not the prettiest and can be downright difficult ,but strength over beauty has to be the most important thing sometimes.

Seems you got the epoxy where it needs to be !

Paul T

[Quaranta]

Aft CR epoxied in place.

[Quaranta]

Assembly Complete. The AeroPack MRS and Rail Lugs will be attached after paint.

Here are the Fwd and Aft sections,... and the obligatory test fit photo.

Next,... sand / fill / paint.

[Handeman]

Forward CR attached.
Notch for the piston cord filled with balsa / epoxy.
Fillets added fwd /aft of CR.
Eyebolt attached with washers either side.

(painters tape now at rear of MMT to align aft CR to MMT while bonding MMT to main BT.)

Wish I had seen this earlier. I would have recommended you turn the eyebolt 90º. Having it the way you do can make it almost impossible to get a quick link attached once it's in the rocket and the BT is close to the eyebolt. Not as much of an issue if you tie directly to the eye bolt. Looks good.

I just finished a 4" Patriot 38mm, but haven't had a chance to fly it yet. Good luck

[Quaranta]

Wish I had seen this earlier. I would have recommended you turn the eyebolt 90º. Having it the way you do can make it almost impossible to get a quick link attached once it's in the rocket and the BT is close to the eyebolt. Not as much of an issue if you tie directly to the eye bolt. Looks good.

I just finished a 4" Patriot 38mm, but haven't had a chance to fly it yet. Good luck

Interesting. I do use quick links. I position the quick link nut to the center of the rocket, and they are always a #*&^% to tighten. Next 4" tube I assemble, i'll test orientations. Thanks.

[Quaranta]

Fillets sanded. Airframe sanded.

Nosecone sanded (I start with 60 grit on plastic nosecones trying to get paint to stick...).

1st coat of primer sprayed...

[MasonH]

I wish my L1 rocket was built as quickly as yours!! Nice job on the fillets!

[Quaranta]

I wish my L1 rocket was built as quickly as yours!! Nice job on the fillets!

Thanks. It's a simple build,... so it's just a matter of doing it. The sanding / painting process will take 3x as long as the build.

I just realized the next Launch is Labor Day Weekend,... and I have Yacht Club Commitments that weekend (translation: 3 day party with endless BBQ/seafood/drinks/water slides etc). I have to decide if I want to skip out for the better part of the day,... or postpone until October.

[sodmeister]

Geeze ,that is a tough decision ! Fillets look nice BTW ,and like you say ,the build goes quick ,it`s the painting that eats up the time.

Gonna be a nice rocket !

Here`s mine on a CTI J270 green.

Paul T

[JStitz]

I still have my original PML phenolic Patriot booster,nosecone, and a tiny bit of the original payload. It is painted in that cool Testors Olive drab with gloss black fins and cone.( will never buy those little cans any more!)
I have been through the second non-glassed payload and had glassed an extended 4" payload section 48" for higher impulse 38mm motors.

[Quaranta]

Geeze ,that is a tough decision ! Fillets look nice BTW ,and like you say ,the build goes quick ,it`s the painting that eats up the time.

Gonna be a nice rocket !

Here`s mine on a CTI J270 green.

Paul T

Fantastic photo Paul. Would love to have convenient access to a field without trees!

But then again,... here's my 6 y/o last weekend... I guess rocket eating tree's are the compromise!