Thinking about a PML Amraam 2

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Antares JS

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I can't speak to the AMRAAM 2 specifically, but I do love PML kits. I picked them over LOC when I was starting out in high power. Quantum tube is great, as long as it's not cold out.
 

Crazyrocket

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I still fly mine and its about 15 years old. Used it to cert Level 1. Usually fly it on a G67 or similar motor. I have about 40 flights on it. Great rocket kit. I would highly recommend it!
 

Back_at_it

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When I first built mine I thought it had some nice features. I thought the piston ejection system was a good idea, I like the materials etc. At the time I was new to Fiber glass so there was a little bit of a learning curve but over all I was happy with the end result. Or so I thought. . . .

I did the stability test and added weight until it checked out fine. The first flight on a mild for that rocket F44 (also used for stability testing) caused the rocket to sky wright and ultimately land in the tall weeds unharmed. Only thing I could think of was the piston and recovery gear was farther forward during the stability test. I went back and added additional nose weight and tried again a few weeks later. Same F44 gave me a straight but low flight.

At some point in the future I began flying it on F67's and found that it gave me nice 700ft flights. I was happy until I started having issues with the ejection piston. Keep in mind that I was sure to clean the inside of the rocket between flights but eventually the piston system became unreliable. After the 2nd failure I decided to remove the piston system. Problem is that to do so correctly and remove all of the harness you need to cut the rocket in half. That same tough construction that allowed it to survive all of the accidents made it a real pain in the butt to modify.

I ended up removing the piston and installing a more traditional ejection baffle with a much thinner Kevlar recovery system. After all the surgery I ended up losing about 6oz of weight. My flight log currently shows an empty weight (no motor) of 23oz. This is down from 29oz before surgery.

Long story short. It's great rocket but leave the piston put of the rocket and you'll be much happier. On a side note, I have the PML "IO" as well and after about 6 or 8 flights the piston in that one became unreliable as well. I haven't had time to put that one under the knife so it hasn't flown in a about 18 months.
 

n3tjm

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Yeah, I am thinking about leaving out the piston. I was actually debating on should I pick up and IO too.
 

Crazyrocket

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I left the piston in mine and have not had any issues. After a flight, I pull out the piston and wipe it down and I wash out the tube and dry it. During construction of the rocket, I put the tube in the freezer and sanded the piston enough that it would easily slide up and down the tube when pulled out of the freezer. I did not want the piston sticking in cold weather. I do have a 3" PML AMRAAM that I did remove the piston. I just cut it right below the piston and then tied additional lengths of tubular nylon to the strap. Never had any issues that way either.
 

Back_at_it

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I left the piston in mine and have not had any issues. After a flight, I pull out the piston and wipe it down and I wash out the tube and dry it. During construction of the rocket, I put the tube in the freezer and sanded the piston enough that it would easily slide up and down the tube when pulled out of the freezer. I did not want the piston sticking in cold weather. I do have a 3" PML AMRAAM that I did remove the piston. I just cut it right below the piston and then tied additional lengths of tubular nylon to the strap. Never had any issues that way either.

The piston in both of mine were very loose to begin with so no sanding was needed. Didn't think about contraction on cold days but looking at the flight log, the last two back to back failure were in summer. One in July and the other in late Aug. so I that wasn't a factor in mine.

My cleaning process sounds like yours. Wipe it out with a old cloth after the flight then clean the inside with a house hold cleaner and a old rag when I get home. There was no visible build up on the inside walls when I cut my AMRAAM in half to modify so I'm not thinking that was the issue. If I had to point a finger at something I'd say that maybe the piston was too loose and was either rocking in the bore and getting stuck or letting too much pressure escape. Either way, I've gotten three more successful flights on that rocket after adding the baffle. Losing some weight was an added benefit.
 

Pem Tech

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As my title says, I am thinking about getting myself an Amraam 2. What do you guys think about this kit?

The AMRAAM 2 was my first AP rocket. Love the Quantum tubing and fiberglass fins for the lack of filling and sanding. Plus it is a good looking rocket, all military and tough looking. The piston ejection was a new experience and found to be temperature sensitive. The big story was that I had never seen an AP motor launch, let alone pushed the button. So I loaded it up an F40, cut my finger on the copperhead, shoved it up the pipe and pushed the Go switch. From 6 feet away.
Yeah, it was quite a startlement. Seem to remember jumping and shouting something like MOTHER OF COD while choking on the bellowing white smoke.
But to the point, it is a great kit you will enjoy.
 

hball55

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+1 on keeping the piston. I have never had a problem with the piston system. On the other hand, on a couple of my larger diameter PML rockets, I did convert the piston into a baffle; either way works.

Warning: LOC is out of stock on many of the PML kits and I have already seen one PML kit converted to LOC tubing; so who knows if LOC will keep the Quantum tube or only until the current stock runs out. The 2.1 Amraam is currently in stock.
 

n3tjm

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I pulled the trigger on it:
Two Rockets.png
 

n3tjm

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Got my Amraam 2 today. Looks like a nice kit. Need to buy some epoxy and some more sandpaper tomorrow to be able to put it together. I am looking forward to it :D
 

hball55

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I pulled the trigger on it:
View attachment 502135

Just my opinion, but you should have ordered the 38mm option on the IO. You should also consider using two-part expanding foam to encapsulate the fins on both the Amraam 2 and the IO. LOC has the two-part foam.

Congratulations . . . btw, I have both these kits. Currently building the IO, or I should say building for the second time due to my first IO being damaged beyond repair several years ago.
 

Jim Hinton

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My AMRAAM 2 flies quite well on a G, it can definitely handle the power of an H. The airframe is a little snug with a chute release, but it will go when carefully packed. AMRAAMs are an easily acquired taste.

Jim
 

n3tjm

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Just my opinion, but you should have ordered the 38mm option on the IO.

I briefly thought about ordering the 38mm version. Launch Lab did have the 38mm in-stock, but I decided to go with the 29mm mount since that is what I will be flying it with.
 

Arsenal78

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I got the 2" one for free already built from my club president. He acquired a lot of built stuff from rocketeers retiring/passed so he let people pick what they wanted. I'll mainly fly mine on probably an F67 or another F motor since we have a lot of trees around here. I love it though. It's phenolic not quantum and probably 15-20 years old I'm guessing. It has brass 1/4" lugs on it which I would like to rip off and do rail buttons instead.
 

crossfire

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I got the 2" one for free already built from my club president. He acquired a lot of built stuff from rocketeers retiring/passed so he let people pick what they wanted. I'll mainly fly mine on probably an F67 or another F motor since we have a lot of trees around here. I love it though. It's phenolic not quantum and probably 15-20 years old I'm guessing. It has brass 1/4" lugs on it which I would like to rip off and do rail buttons instead.
Leave the lugs on and put buttons on another side
 

tjsnakez

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I had an Amraam 2 from 2003-2019. I usually flew it at least once every launch. I don't have a flight log, but I would guess I had close to 100 flights on it. Early in it's life it had a steady diet of F20 and F23 EconoJets. After a couple years I swapped out the chute for a skyangle that was a couple ounces heavier than the stock chute. After that it was G's and H's. I flew every 29/180 and 29/240 load in it no problem. The piston worked great - just check it before every launch and make sure it moves freely, and sand if needed. Also it's a good idea to reduce the ejection charge to .75g in the HP style Aerotech cases.

Ultimately lost it to a failed ejection charge in a 25 year old G80. I should have known better. I would like to build a new one at some point.
 

hball55

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Leave the lugs on and put buttons on another side

And effectively double the drag on the rocket? I ran a sim on a 2” rocket without rail buttons and then with rail buttons and I was surprised when the difference in altitudes was nearly 800’.
 

hball55

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Never would have guessed that. What motor?

It ran the gamut of motors (all motors). Try it, if you have Rocksim, run sims with and without rail buttons. Hopefully, I wasn’t doing something wrong; I created rail buttons using the custom fins tab, changed the number of fins to one for each separate button, and changed the plan points to the dimensions of the rail buttons.

I misstated the doubling of drag, what I meant was doubling the drag that the rail buttons and lugs create.
 

Crazyrocket

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I have a hard time believing the sim and that with and without rail buttons that there would be an 800' difference in altitude. I routinely fly mine with G54 motors which gives and altitude around 800 feet (visual estimate). It has both lugs and buttons. Hard to believe that if I removed them I would get 1600'. May be I misunderstood your comment.
 

n3tjm

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Decided to order a nice accessory for my Amraam 2 and Io.
 

hball55

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I have a hard time believing the sim and that with and without rail buttons that there would be an 800' difference in altitude. I routinely fly mine with G54 motors which gives and altitude around 800 feet (visual estimate). It has both lugs and buttons. Hard to believe that if I removed them I would get 1600'. May be I misunderstood your comment.

First, do you have Rocksim? If you don’t then you won’t understand what I am saying. If you have Rocksim, run a sim with neither launch lugs or rail buttons. Then run a sim with launch lugs and run a sim with rail buttons. Perhaps even run a sim with both at the same time, that would be interesting.

What I said is that I ran sims on Rocksim with several motors, without any type of guide (lug or button). Then I ran sims with the same motors with rail buttons installed and the altitudes the sim showed altitudes nearly 800’ lower than the previous sims.

What actual results at your launch site will be, I don’t know, I was just reporting what Rocksim said. Is that clear enough?
 

Crazyrocket

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Understood. And yes I have rocksim and also use openrocket. I was just commenting on my real world experience and suggesting that the sim doesn't seem to reflect what I would expect when you actually fly the rocket.
 

boomtube-mk2

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One thing you can do with the piston to improve reliability is to burnish the outside surface with a powered graphite lubricant.
Hob-E-Lube is one brand.
 

hball55

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Understood. And yes I have rocksim and also use openrocket. I was just commenting on my real world experience and suggesting that the sim doesn't seem to reflect what I would expect when you actually fly the rocket.

You can change launch conditions (ie. temperature, humidity, altitude of launch site, winds, etc.) in Rocksim, to match the conditions at your launch site. Early on, I didn’t know that and I had large variances between the sim and actual results. So, there’s that variable to think about when comparing the sims and actual launch day results.
 

n3tjm

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Amraam.jpg

Pretty much got my Amraam Assembled. My arm is really aching from sanding the piston down to get it to fit. Got some Rail Buttons Ordered from LOC (add on during an e-bay purchase for another project) and Ordered some Aero Pack 29mm Retainers from Apogee. Me-thinks this rocket will fly real nice with F62T and G104T motors. I need to get myself some cases for those loads.
 

Arsenal78

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Whoever built the one I have didn't leave any motor tube for a normal retainer, I think it was designed for a triangle shaped screw on plate which I didn't have so I had to get a new flat bottom retainer which I kind of prefer more, though I was misled by Apogee on it actually being for flat bottomed rockets. I'll try and get a picture of it.
 

hball55

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Whoever built the one I have didn't leave any motor tube for a normal retainer, I think it was designed for a triangle shaped screw on plate which I didn't have so I had to get a new flat bottom retainer which I kind of prefer more, though I was misled by Apogee on it actually being for flat bottomed rockets. I'll try and get a picture of it.

I had that same problem and I took a dremel tool and cut away the centering ring around the mmt and was able to install an aeropac retainer.
 
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