Installing a screw-on motor retainer on a kit

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lcorinth

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I just got my first mid power rocket kit - a Quest Big Dog. The Apogee Components website recommends installing a screw-on motor retainer on this rocket, as there's no retainer in the kit. It has a 29mm motor tube and a 24mm motor adapter for D and E motors (well, it's not long enough for an E - another recommendation by Apogee is to use a different adapter if you wish to fly with E motors). The rocket has a 29mm, 4.5 inch long motor tube, wound paper thrust ring, and fiber centering rings.

I've never used one of these before. Do I simply glue it on to the end of the motor tube included in the rocket? Do I need to modify my kit construction if I opt to install one? And, if I do install one, am I still able to fly with black powder motors, or do I need to stick with composite? I don't mind if that's the case - I want to gain experience using composite motors, so if I have to choose, I'd make this a composite motor rocket.

Also, do you have a recommendation for a retainer? Apogee recommends Aero Pack, but when I asked about this on the NAR Facebook page, I got a lot of conflicting opinions (i.e. "Aero Pack is best" vs. "Aero Pack is too expensive for this rocket - go with Estes retainers"). Nobody gave me any advice on installation, however, so I thought I'd ask here.

Thanks!
 
Install with JB weld. Do not install the motor block. The estes retainers are $8 for two. Aeropacks are $25 for one. Both work just fine. I've got a pair of estes in a cluster rocket and I've fired everything up to a couple of I200W's in there. Little toasty, but still work just fine.

To use BP motors, either make a tape thrust ring at the rear of the motor, or cut off a spent motor and glue one to the end of the motor.

Estes (right after it's 6th flight): I'll burn out the rear end before these fail.
14044698134_4e8b3dd1c0.jpg


Aeropack:
14949838693_bc4693072c_n.jpg
 
Install with JB weld. Do not install the motor block. The estes retainers are $8 for two. Aeropacks are $25 for one. Both work just fine. I've got a pair of estes in a cluster rocket and I've fired everything up to a couple of I200W's in there. Little toasty, but still work just fine.

To use BP motors, either make a tape thrust ring at the rear of the motor, or cut off a spent motor and glue one to the end of the motor.

Estes (right after it's 6th flight): I'll burn out the rear end before these fail.
14044698134_4e8b3dd1c0.jpg


Aeropack:
14949838693_bc4693072c_n.jpg

So, do you epoxy these right over the motor tube? Do you adhere them to the rear centering ring?
 
I just got my first mid power rocket kit - a Quest Big Dog.

LOL, I'm back in model rockets again after 30 years, and my Big Dog is in the mail...

I was researching the same thing, and noticed that (similar to the response above) on the Apogee website at:

https://www.apogeerockets.com/Build.../Screw-On_Retainers/Estes_29mm_Motor_Retainer

they state:

"To use these retainers, you'll first scuff up the inside of the inner ring with sandpaper. This will allow your adhesive to better grab to the plastic ring. For the adhesive, Estes recommends epoxy. I believe that regular 5-minute epoxy you purchase at a hardware store will be sufficient for most rockets."

Regarding longevity, everybody I have read states that the plastic Estes retainers are just as good as the metal ones, and more than likely will outlive your rocket, so that's the way I'm going to go...

Cheers!
 
So, do you epoxy these right over the motor tube? Do you adhere them to the rear centering ring?

They both go over the tube, and I typically have them seat right up to the rear CR.

15602010341_c602ab6b41.jpg
 
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LOL, I'm back in model rockets again after 30 years, and my Big Dog is in the mail...

I was researching the same thing, and noticed that (similar to the response above) on the Apogee website at:

https://www.apogeerockets.com/Build.../Screw-On_Retainers/Estes_29mm_Motor_Retainer

they state:

"To use these retainers, you'll first scuff up the inside of the inner ring with sandpaper. This will allow your adhesive to better grab to the plastic ring. For the adhesive, Estes recommends epoxy. I believe that regular 5-minute epoxy you purchase at a hardware store will be sufficient for most rockets."

Regarding longevity, everybody I have read states that the plastic Estes retainers are just as good as the metal ones, and more than likely will outlive your rocket, so that's the way I'm going to go...

Cheers!

Thanks for the link! I had been looking around the Apogee site for this (I went there for the RockSim file and any useful information on the rocket), but I hadn't found that particular page. Guess I should've looked more!
 
Thanks for the pic! Makes it much more clear. Seems pretty simple.

Photos? I have an annoying amount of those...
5763246368_fe57a8582c.jpg
6746630129_025a222dac.jpg

6221593597_3ee9639ffc.jpg
6225481662_95370f48a7.jpg


tip: remove the cap and tape over the threads when installing. Keeps from gluing the cap on, or fouling the treads....ummm don't ask... Also use some alcohol to wipe out the inside where the JB weld will squeeze out a bit... if you leave it it will make motor insertion difficult.

13864309963_0802ecc3ea.jpg
 
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One thing nobody has mentioned is to leave enough MMT tube sticking out of the rear centering ring to JB Weld the retainer too, depending on the brand it will require up to 1/2 inch of motor tube. (Then again maybe someone did post that and I just failed to observe it)
 
Good point I did forget that. I either dry fit and mark the motor mount where the cr needs to be, or epoxy the retainer on, and push the cr into it, depending on the order of the particular build. It doesn't need to absolutely be against the cr. In some builds the lower cr needs to be up higher to meet the fin tabs, and the motor lower to avoid burning the tube, or there needs to be spacing for a tailcone. In those cases not meeting the cr is fine. Just look at the build and your goals and decide the best way from there.
 
I've used several of the estes retainers also with good results. although with the new aerotech aluminum retainer for $14 I'll be trying one of those soon. I use the retainer to set how much motor tube sticks out and set it so the retainer will glue to the tube and the rear ring. I sand the crap out of the retainer with 40 or 50 grit paper and glue it on with JB weld.
2GXIXyYa_3YTHM0lqCcQP_IaDY5-vA1I_bhksvRm32E=w769-h577-no

419.JPG
 
Thanks for the link! I had been looking around the Apogee site for this (I went there for the RockSim file and any useful information on the rocket), but I hadn't found that particular page. Guess I should've looked more!

Not a problem...the Apogee website is chock-full of info, but it is a tad bit hard finding *exactly* what you need, when you need it.

Thanks for posting the question, btw...it is saving me some time, as this was a question I would have been asking myself very soon.

(BTW, I enjoyed your blog--again, I'm laughing, as both my Big Dog and my Quad Runner are in the mail...we seem to have very similar rocket tastes!).

Also, to everybody kind enough to post photos of the retainers while you are building the models, thanks so much! It really, really, helps to have a photo along with the written description. I really appreciate you all taking the time out to post advice and photos.

Cheers!
 
Not a problem...the Apogee website is chock-full of info, but it is a tad bit hard finding *exactly* what you need, when you need it.

Thanks for posting the question, btw...it is saving me some time, as this was a question I would have been asking myself very soon.

(BTW, I enjoyed your blog--again, I'm laughing, as both my Big Dog and my Quad Runner are in the mail...we seem to have very similar rocket tastes!).

Also, to everybody kind enough to post photos of the retainers while you are building the models, thanks so much! It really, really, helps to have a photo along with the written description. I really appreciate you all taking the time out to post advice and photos.

Cheers!

Hey, thank you!

The Quad Runner has me scratching my head a little. It has two-piece fins, and the directions say to assemble them on a piece of wax paper with wood glue, then apply them to the rocket when dry. I'm worried this might be an easy way to get them crooked at the joint. So, I'm considering putting the main part of the fins on the rocket with my guillotine fin jig, then applying the little strakes with the help of some aluminum angle and clamps, but I don't know how that will turn out either.

Also, I'm not sure how easy that will make it for me to fill them, or to sand an airfoil or at least a rounded edge. If you figure this out, hit me up.

My Estes retainers came in the mail today. I'm all set to build the Big Dog - if only I had a place where I could paint indoors. I can't finish my rockets, because it's too cold!
 
the Estes 29mm retainer comes with a pretty good installation instructions. Aero pack's instructions can be a smidge confusing for a 1st timer.
Rex
 
Hey, thank you!

The Quad Runner has me scratching my head a little. It has two-piece fins, and the directions say to assemble them on a piece of wax paper with wood glue, then apply them to the rocket when dry. I'm worried this might be an easy way to get them crooked at the joint. So, I'm considering putting the main part of the fins on the rocket with my guillotine fin jig, then applying the little strakes with the help of some aluminum angle and clamps, but I don't know how that will turn out either.

Also, I'm not sure how easy that will make it for me to fill them, or to sand an airfoil or at least a rounded edge. If you figure this out, hit me up.

My Estes retainers came in the mail today. I'm all set to build the Big Dog - if only I had a place where I could paint indoors. I can't finish my rockets, because it's too cold!

clamp them between two marble tiles, lined in wax papepr.

Re: Quad Runner fins, I have two large hard back books that I was going to use to lay the Quad Runner fins on, between sheets of wax paper, to ensure they are glued on straight. Hopefully that will do the trick.

Painting is tricky...it has been cold here (central CA) as well, which I am not used to. It may get up to the 70's today, so I'm going to see if I can get anything done.

I'll attach the Apogee newsletter web link that covers finishing a rocket, he has some good tips in there about painting that I am following (like, it is probably more important that the can of paint and paint is warm, than the outside air). However, I would expect that below a certain threshold (I would guess 60 degrees F) I wouldn't want to chance it, or hang out outside shivering while I'm trying to paint something.

https://www.apogeerockets.com/downloads/Newsletter298.pdf
 
Re: Quad Runner fins, I have two large hard back books that I was going to use to lay the Quad Runner fins on, between sheets of wax paper, to ensure they are glued on straight. Hopefully that will do the trick.

Painting is tricky...it has been cold here (central CA) as well, which I am not used to. It may get up to the 70's today, so I'm going to see if I can get anything done.

I'll attach the Apogee newsletter web link that covers finishing a rocket, he has some good tips in there about painting that I am following (like, it is probably more important that the can of paint and paint is warm, than the outside air). However, I would expect that below a certain threshold (I would guess 60 degrees F) I wouldn't want to chance it, or hang out outside shivering while I'm trying to paint something.

https://www.apogeerockets.com/downloads/Newsletter298.pdf

I was thinking of attaching the base fins with my guillotine fin jig, then attaching the strakes using two pieces of aluminum angle as a guide. But I'm not sure if I should fill them with CWF first, or if I need to worry about sanding the base of the strakes too much and making them not match up... I just want to get the fins on straight. Everything else, I'm comfortable doing. But this will be my first rocket with two-part fins.
 
...My Estes retainers came in the mail today. I'm all set to build the Big Dog - if only I had a place where I could paint indoors. I can't finish my rockets, because it's too cold!
FWIW, I often finish rockets in the cold, well below freezing. Keep the rocket & paint warm, take outside only while spraying each coat. If you want no smell at all inside, keep the rocket out between coats, but bring the paint in. With lacquers (re-coat anytime), this works fine. A little trickier for re-coat within 1 hour enamels, but still do-able.
 
FWIW, I often finish rockets in the cold, well below freezing. Keep the rocket & paint warm, take outside only while spraying each coat. If you want no smell at all inside, keep the rocket out between coats, but bring the paint in. With lacquers (re-coat anytime), this works fine. A little trickier for re-coat within 1 hour enamels, but still do-able.

Maybe I'll try this. I'm building a few new ones I really want to launch, winter be d@#&ed, and I don't want to wait until spring to paint them.
 
One thing, is you are using a 29mm MMT on on a 38mm air frame, you may want to use something other than the Estes Retainer. The reason, is that the "nut" for the estes retainer is larger than 38mm, and could screw up your placement of lugs/railbuttons. The Aeropack 29mm retainers do not obstruct anything in a 38mm airframe.

Also, with Aeropack, you can buy a "full set" (the part attached to the MMT and the "nut",) and for other birds, just buy the part attached to the MMT, and then use the same "nut". It saves a bunch.....
 
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Big dog is 2" I think, which should work with the estes retainer. However, you do either need a lower profile retainer or rail standoffs for 38MM rockets and smaller.
 
Also, the estes retainers fit in the estes 2" kits, so they will probably work in the 2" big dog.
 
One thing, is you are using a 29mm MMT on on a 38mm air frame, you may want to use something other than the Estes Retainer. The reason, is that the "nut" for the estes retainer is larger than 38mm, and could screw up your placement of lugs/railbuttons. The Aeropack 29mm retainers do not obstruct anything in a 38mm airframe.

Also, with Aeropack, you can buy a "full set" (the part attached to the MMT and the "nut",) and for other birds, just buy the part attached to the MMT, and then use the same "nut". It saves a bunch.....

Big dog is 2" I think, which should work with the estes retainer. However, you do either need a lower profile retainer or rail standoffs for 38MM rockets and smaller.

38mm is about 1.6", and the Estes "nut" is larger than that, so be carefull!

Check to see if things fit ahead of time, before I glue it together? Why would I ever do that?

Thanks for posting this info, this likely has saved me a big face-palm later. I've been stocking up on the Estes motor mounts, as they are cheap...but obviously not for every kit. Those new Aerotech aluminum mounts look really, really nice, and aren't that much more expensive, now.
 
Check to see if things fit ahead of time, before I glue it together? Why would I ever do that?

Thanks for posting this info, this likely has saved me a big face-palm later. I've been stocking up on the Estes motor mounts, as they are cheap...but obviously not for every kit. Those new Aerotech aluminum mounts look really, really nice, and aren't that much more expensive, now.

If you have something like a 54mm or larger AF and a 29mm MMT, madcow has a very cheap option. Their motor retainer is a piece of flat SS, in the correct shape, with two #6 screws, and two brass wood nuts. To use it on another rocket, all you really need is (2)#6 tnuts to mount in the rear CR.
 
I used the Estes 29mm retainers on my souped up Mean Machine, yes it sticks out around a BT-60 but its only about as much as the vertical ridges on the nut and it doesn't interfere with my 1/4" lugs mounted direct to the BT.
 
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Hey, thank you!

The Quad Runner has me scratching my head a little. It has two-piece fins, and the directions say to assemble them on a piece of wax paper with wood glue, then apply them to the rocket when dry. I'm worried this might be an easy way to get them crooked at the joint. So, I'm considering putting the main part of the fins on the rocket with my guillotine fin jig, then applying the little strakes with the help of some aluminum angle and clamps, but I don't know how that will turn out either.

Also, I'm not sure how easy that will make it for me to fill them, or to sand an airfoil or at least a rounded edge. If you figure this out, hit me up.

My Estes retainers came in the mail today. I'm all set to build the Big Dog - if only I had a place where I could paint indoors. I can't finish my rockets, because it's too cold!


I recently built an Estes Xarconian Cruiser, it has two piece fins.. I sandwiched the fins between wax paper and books - turned out good. Those fins had rounded edges as well. I had to sand a bit of excess glue but that method works just fine. Can probably paper em afterwards if you worried about finishing or strength, though the joint will be the strongest part of the fin. I can't help help ya with papering, never tried it

Mike
 
I will install the retainer and the centering ring at the same time. That way you are sure to get it right. Use glue of choice to secure retainer to motor tube, then slide the centering ring into place and add glue as needed. Easy.

Did just that not five minutes ago with a 29mm mega mosquito build. Added an estes retainer and ply rings. Gonna be one bad skeeter!

See ya,
Rod
 
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