Estes Leviathan "Stretch" Build Thread

[dmgrime]

Hi all! This is my first build thread, so please go easy I'm building an Estes Leviathan, but making a few modifications:

1) Adding 34" of T300 airframe from BMS

2) Replace stock motor mount with 34" T52HMF foil lined motor/stuffer tube to ensure standard motor deploy charges can pressurize the extended airframe properly.

3) Anti-Zipper Design breaking at ~44"

4) Possibly adding nose cone AV bay for EggFinder (TBD)

Here goes .... (been taking this slow, so this is likely to be built out over the next 2-3 weeks)

Dave

 

[dmgrime]

Here's the MMT/stuffer tube already glued in to the stock Leviathan fin can tube. I also have added a top centering ring which will, of course center the stuffer, but also seal off most of the airframe so only the top ~10" needs to pressurize (I'll be putting a baffle in the anti-zipper coupler). This is an all wood glue assembly, except for the JB weld I'll use on the motor retainer (Estes stock), and also for this coupler as I didn't want to risk the next step binding ...

And I also included a backer block made from 3/4" maple plywood to support the rail button. The aft CR will have the same, but I'm leaving that off for now to be able to do internal fillets.

 

[dmgrime]

And here's the assembled lower airframe. To put the two pieces together, I put a ring of wood glue 11" down from the top, then inserted the MMT about 12" in from the bottom of the 34" airframe section. Then, I put another ring in the aft end (working around the MMT) about 4" up. I slathered the exposed coupler with RocketPoxy and hoped for the best. Thankfully it didn't bind and I got a nice bead of glue that will seal the top of the MMT assembly ...

 

[Bat-mite]

Cool! If you do the nose cone AV bay, I will be watching avidly. I want to do mine, but I'm trying to find a cone that isn't sloped on the bottom that will fit the Estes tube.

 

[dmgrime]

Debating the anti-zipper or just a baffle on top of this assembly ... thoughts?

If I anti zipper I planned a bulkhead about 10" inside the upper airframe to minimize the laundry compartment and ensure full deployment.

So many choices ....

 

[K'Tesh]

Did you glue the aft CR in place? Hopefully you didn't (it allows you to do internal fillets).

 

[dmgrime]

Aft CR is not installed yet, and definitely planning on internal fillets. The nice thing is the rail button block also serves as a nice handle to be able to put it on and take it off while installing the fins! Then I'll flip it when I glue it in so the block is on the inside of the fin can ...

 

[dmgrime]

Starting fin installation .... first fin setting up. Jig is from an old TRF thread - so far this will be the largest I've tried it on, and the fin is mostly hanging off ... might need to build a bigger one! Anyhow, the aft CR is just slipped on, and the rail button block makes a convenient handle to take it back off for internal fillets!

Once I get all the fins done, I'll move on to internal fillets then glue in the aft CR.

 

[Handeman]

Debating the anti-zipper or just a baffle on top of this assembly ... thoughts?

If I anti zipper I planned a bulkhead about 10" inside the upper airframe to minimize the laundry compartment and ensure full deployment.

So many choices ....

I'm not sure what you mean about anti-zipper. The ones I've seen have a coupler extend out the top of the lower BT, and the CR at the top of the coupler is the one that hold the top of the MMT. You have the top of the MMT well down inside the lower BT. Are you intending to put another coupler at the top of the BT and a CR at the top of the coupler? My understanding of anti-zipper is that the shock cord is attached to a point that is above the lower BT, usually at a CR in the top of the coupler.

 

[dmgrime]

I'm not sure what you mean about anti-zipper. The ones I've seen have a coupler extend out the top of the lower BT, and the CR at the top of the coupler is the one that hold the top of the MMT. You have the top of the MMT well down inside the lower BT. Are you intending to put another coupler at the top of the BT and a CR at the top of the coupler? My understanding of anti-zipper is that the shock cord is attached to a point that is above the lower BT, usually at a CR in the top of the coupler.

Yes, adding another coupler with drilled bulkheads (a series of smaller holes around outside edge), and a u-bolt on the side that extends out of the booster. I'd then friction fit or rivet or screw the nose on and it would break at the baffle ... or I'd still make this coupler into a baffle but glue the upper airframe on and go normal nose blow ... I only used the longer MMT to act as a stuffer to reduce the overall airframe volume that needs to be pressurized on ejection.

I'm currently thinking mid break/anti zipper and including a replaceable steel mesh inside the coupler similar to aerotech baffles.

 

[dmgrime]

All 4 fins attached ... first set of fillets (internal and external) down ... 3 more to go, then I'll button up the aft end and attach the motor retainer. Still deciding on the top side .... leaning anti-zipper with removable/replaceable steel mesh baffle, but not sure!

 

[dmgrime]

One downside of an all wood glue approach ... wood glue dries pretty slowly Hah! Finally got the last set of internal and external fillets done this evening .... once they dry I'll get the aft CR installed and update the post, though that won't be until the weekend as I'm heading out of town for work tomorrow.

 

[dmgrime]

So back from my trip and a great day as a spectator at LDRS34 on Friday. Got some time this weekend to do all of the external "finish" fillets, as well as get the aft CR glued in. Moving to the recovery side next, but here's a few shots of my first try using tape to mask my fillets, and a plastic spoon to shape them. Still need some work on where the front edge of the fin meets the airframe, but overall these came out quite well. Glue was Titebond no-run no-drip (FKA TMTG).

Masked:

Glue before spoon:

Pulled Fillet:

Tape Removed:

Dry:

 

[Zeroignite]

Your photos aren't showing for me.

 

[dmgrime]

I couldn't get direct image uploads working, so these are Google drive "permalinks". I'll see if there is something else I can do ...

 

[dmgrime]

I couldn't get direct image uploads working, so these are Google drive "permalinks". I'll see if there is something else I can do ...

I moved all of my pics to a TRF album, and edited the post to reflect ... still not sure how to make it so you've got thumbnails in the main post with the popup to see the full size images with prev/next links ... once I figure that out I'll probably switch.

 

[K'Tesh]

Looking Good so far...

What you gonna do for your color scheme?

 

[dmgrime]

I moved all of my pics to a TRF album, and edited the post to reflect ... still not sure how to make it so you've got thumbnails in the main post with the popup to see the full size images with prev/next links ... once I figure that out I'll probably switch.

Not sure yet ... honestly it's been such a dismal spring/summer so far, painting is the furthest thing from my mind right now! Gut feeling is either stock paint scheme, or a white and black approach. Since I'm planning mid break at the top of the extended lower airframe, I'd go black from the nose down to there, then white for the lower airframe, and do alternating black and white fins. Still not sure though :wink:

 

[CZ Brat]

Starting fin installation .... first fin setting up. Jig is from an old TRF thread - so far this will be the largest I've tried it on, and the fin is mostly hanging off ... might need to build a bigger one! Anyhow, the aft CR is just slipped on, and the rail button block makes a convenient handle to take it back off for internal fillets!

Once I get all the fins done, I'll move on to internal fillets then glue in the aft CR.

FYI. A have learned a trick for jigging TTW fins (only works for 4 fins) and the fins extend below the BT. Put in two opposing fins and turn the BT upside down so aft end is up. Then take a piece of angle aluminum and set it atop the end of the BT and clamp the two fins to it. Gets them both perfectly aligned. Then repeat for the next pair of fins.

 

[dmgrime]

I'll have to try that on my next one (couldn't resist estes 4th of July sale! ) - thanks! Made a little more progress and will post some pictures tomorrow ... aft CR glued on, motor retainer affixed using JB weld and exposed side of aft CR covered in a layer of glue.

Next I'll move on to the coupler which I plan to make into a cleanable/replaceable chore boy baffle and also be the break point for this rocket.

Slow going but hoping to get some more done this week!

 

[dmgrime]

Finally got around to getting a picture of the motor retainer installation. I'll be working on the baffle/coupler this week and get some pictures up as time permits!

 

[dmgrime]

Finally getting back to this build! Got the baffle assembly built, smeared a layer of JB weld on the engine facing side.



The all thread is to make the top part of the baffle removable for checking the status of the chore boy that will live in the coupler.



Recovery will attach to a U bolt on the other baffle plate.

 

[dmgrime]

Upper section recovery harness installed to coupler which has a doubled bulk plate on the fore end with a U bolt facing aft.



Paracord attached with a uni knot, and a welded steel ring to tie to the booster and chute.



Should finish main construction tomorrow night ... winter here in the northeast so probably not painting until spring ...

 

[dmgrime]

"Stretch" finally flew today ... her maiden voyage was for my L1 cert flight. First flight of the rocket, flying my first ever reload (Aerotech H128-W in the 29/180 case).

Super calm winds at the launch site today, and extra lucky with recovery about 50 feet from the flight line.

That sucking sound? Yeah, I know, my wallet being bled dry!

 

[K'Tesh]

Congrats on the Cert!

You should know that that sound you mentioned gets louder in a direct relationship to the volume of the motor.

 

[noffie79]

Congrats on the Cert!

You should know that that sound you mentioned gets louder in a direct relationship to the volume of the motor.

Truest. Statement. Ever.

 

[Rex R]

also grows louder as one gets closer to Tim's trailer
Rex

 

[Crash-n-Burn]

Congrats! Where did you do your cert flight? I swear I saw a rocket just like that fly today...

 

[dmgrime]

Syracuse Rocket Club (NAR 566). Upstate NY.

 

[Crash-n-Burn]

Well dang, it wasn't you. All the same, congrats.