Little Joe II repair thread

[mjennings]

I have a Estes Little Joe II, that recently suffered some hanger rash, LES tower broke off. So it got moved to the fix it hanger. I went to fly this rocket a several months ago and none of the 13mm motors I had in the range box wanted to fit. I decided the motor mount was warped and put it back in the car to be retired. (this is my first attempt at motor mount repair) I said to my self the other night,
"Self"
"Yes?"
"If you're going to glue the LES back on why not fix the motor mount too?"
"Hmm, not a bad idea, and if it looks like I'll do more damage to the rocket by removing the mount she's already semi-retired and I'll stop and just reattach the LES"
So I set out to fix my Little Joe II

First I remembered, didn't I field repair the motor mount in about 2001 with CA, that should make things interesting (First exposure to CA, I was flying with a friend, from college, and his kids the MM popped out and he said here use this to fix it.)

looking down the dirty old body tube 1


looking down the dirty old body tube 2


MM successfully removed! Took some pushing and cutting and in the processes I popped a fin off, but that is not a big deal


Shot of the left over glue in the body tube 1


Shot of the left over glue in the body tube 2

 

[Gillard]

i've got a little Joe II,
i always thought it would be nice on an 18mm motor,with a bit of mass in the capsule, she would be stable.
are you going for the standard 13mm or an upgraded 18mm, you could always use an adapter 18mm-13mm if you go for the 18mm.

 

[mjennings]

Just a straight 13mm for 13mm replacement, I got the motor mount built and as I was installing It I thought I should have made this a 4X13 mm mount. Oh well maybe some other time.

 

[mjennings]

The removal of the motor mount used a lot of pushing on the edges of the old centering rings using a X-acto knife handle, and X-acto knife scribe. Cracked the old glue joints and did very little damage to the BT, some localized pealing was the only real issue.

The construction of the new motor mount was more challenging that I had hoped. First I raided my stock of centering rings and centering ring material. I thought I had enough. Took some measurements and cut a ring out of stock, well I cut too small and didn't leave enough space for the second ring anyway. I had some rings from a designers special kit I've had for years, but none the right size. Fortunately there was a 13mm to a larger size than I needed CR so I picked those. These centering rings left a lot to be desired, very flimsy and did not cut or sand down very well. So I added 4 balsa reinforcements to the assembly and sanded like crazy till the assembly fit into the rocket.


Forward view of the cleaned out BT


attach point for the fin I broke off


Motor mount assembly in parts


assembled Motor mount with Kevlar leader 1


assembled Motor mount with Kevlar leader 2

 

[mjennings]

The original damage to the LES was easy enough a few drops of CA, hold in place for a 60 count and good to go. The motor mount was now fully assembled, including a thrust ring cut from a spent casing, the original didn't have a thrust ring. With most of the glue knocked/sanded from the body tube I applied wood glue in place and slid the motor mount forward. The mount grabbed a little before I wanted it to but it should be fine (maybe 1/4 inch). I then touched up and painted as needed. I used plain old Testors red and silver (that is most likely what I used originally and appeared to match pretty well, the new silver is a little shinier)

the repaired LES sitting on the old Motor Mount


New Mount fully installed


Old Mount and repaired rocket before paint


All done ready for return to flight status!!!