Quantcast

HAMR Question

The Rocketry Forum

Help Support The Rocketry Forum:

Pantherjon

Well-Known Member
Joined
Jan 19, 2009
Messages
7,347
Reaction score
1
I am going to be using a Public Missiles 38mm HAMR(Highly Adaptable Motor Retainer) in my Wildman Jr rocket..The thing is when I place the ring on the motor tube there is a bit of 'slop', it isn't snug like I thought it would be..Is this normal? Or should it be fairly snug? When I put it on the tube I can move it from side to side almost a good 1/16 - 1/8"..:confused:
 
Last edited:

talkin Monkey

Well-Known Member
Joined
Jan 18, 2009
Messages
480
Reaction score
0
If were talking about the same part here...:)

The aluminum "ring" goes behind the aft motor closure and then the threaded end screws it all down nice and tight.

EDIT: Oops, I just played with a 29mm version, can't do what I thought you're saying. Are you speaking of the male threaded end too sloppy on the MMT?
 
Last edited:

n5wd

Well-Known Member
Joined
Jan 18, 2009
Messages
1,030
Reaction score
2
...HAMR(Highly Adaptable Motor Retainer) ...when I place the ring on the motor tube there is a bit of 'slop', it isn't snug like I thought it would be..Is this normal?
From the instructions sheet ..."Test fit the sleeve over the motor tube. A loose fit is better than a snug fit to prevent the epoxy from being pushed off."

So sayeth we all... :D
 

SCE to AUX

Well-Known Member
Joined
Jan 18, 2009
Messages
903
Reaction score
3
Mine was a bit loose, as well (about .020" oversize). Leaves room for the epoxy.

Just make sure that the ring is centered before the glue sets. If the ring is shoved over to one side, it might be hard to insert a motor later.
 

Pantherjon

Well-Known Member
Joined
Jan 19, 2009
Messages
7,347
Reaction score
1
Yeah Wayne, it would help to read the instructions!..LOL...So, a loose fit is better then snug, well now..;) Guess I need to get me some JB Weld Tuesday in my gallivanting around on my day off!:rolleyes:

I have never messed with JB Weld before..How long does it take to cure? And if during that cure time while it is still pliable I could insert a motor casing to ensure the ring is centered?(Of course making sure there isn't any of it IN the motor tube first!)
 

n5wd

Well-Known Member
Joined
Jan 18, 2009
Messages
1,030
Reaction score
2
...Guess I need to get me some JB Weld Tuesday in my gallivanting around on my day off!:rolleyes: I have never messed with JB Weld before..How long does it take to cure? And if during that cure time while it is still pliable I could insert a motor casing to ensure the ring is centered?(Of course making sure there isn't any of it IN the motor tube first!)
Putting my HAMR on the MR-1 was my first experience with JB Weld as well. IIRC it takes about an hour for it to set up, and isn't cured completely for 12 hours - it's been a while, so i'm probably a bit foggy on the exact times. Yep, after I got it set in, I slid a used 38mm motor and casing into the mount, just to check, and it lined up just right.

But, I only got to fly it twice - on the second flight, the MR-1 apparently landed on a taxiway butt end first, at the airport where Tripoli Houston flies, and knocked it a little out of round. Had to take pliers to it to get it off and won't thread correctly - gonna send it back home to see if they'll sell me whichever of the parts is out of round, separately.

For my money, it's a nice system, but if you fly it only twice, it can be expensive.
 
Top