Glasspacks' LVL II Build

[Glasspack]

So I have mentioned this goal before.... to build an upscale version of the Sky-Tec Antares model from
Argentina, that I fell in love with. This will be my LVL 2 Cert Model.

Well, with a lot of outstanding help from the Tripoli Club in Argentina and a few awesome gentlemen;
Jorge and Sebastian; I have all the measurements I need to accurately upscale this to a 4" Diameter model to attempt my LVL II Cert.
The first concern I would like to post to all of you is the weight. It will be heavy I know, at over 92" tall. But..holy crap there is a big difference in Fin weight from Phenolic to Birch Ply. I currently have .187" Cotton Phenolic sheets for the two fin sets, the FWD Fin set is listed on Rocksim at 34oz as compared to 6.3oz in Birch.
Perhaps the cotton Phenolic is not worth the weight? I want to build and reach Mach 1 with this cardboard Airframe (eventually) after my Cert. Maybe the weight is not that accurate on Rocksim, I will weight everything of course as I go....

Love to hear your inputs

 

[Nytrunner]

Get the parts in hand and compare weight. I've found the parts database less than thrilling

Looks like a cool rocket! (similar to the Madcow Pike AGM) No one says you have to cert L2 on a J.....54mm mount....., punchy K...., you can get it going

 

[Glasspack]

Oh trust me NY, my cert flight will not be a K motor !!

 

[Glasspack]

Ny, have you used phenolic......is it superior to ply ?

 

[Nytrunner]

If its the canvas phenolic from MAC, id say it is definitely superior to plywood

 

[Glasspack]

So I am going to press on with the Phenolic sheet for my fin set. Thank you Nytrunner.
I will start this weekend with the build....The lower Airframe is not slotted yet so I have to do that.
Finalizing all the measurements and waiting on a couple pieces..

 

[chris m]

Weight will go down . Cert should weigh more . My lv2 maga hi flyer . At 13 lbs was built to be l1

 

[ThreeJsDad]

Ny, have you used phenolic......is it superior to ply ?

I would agree with one exception, if you have the ability to laminate plywood with carbon, kevlar or even fiberglass you will have something you will really like.

 

[Glasspack]

Well I spent a few hours this weekend putting together my "Slot Machine" from Apogee Rockets. I could have used my table saw maybe but I really like the tools that Ted Macklin makes so I got another one.
My small Bosch router will work great and I can make nice slots in tubes up to like 8" now.

The new nose cone is over 19" exposed length and 5:1 O-give .... I like it.


And the conical nose cone is going to be cut to make the tail cone. I need about 4.5" of it exposed.. hope I can get it to work well.
Even have a Slim lime retainer for the 54mm motor. Want to hide most of it with the tail cone.

 

[Glasspack]

I have been working on the Rocksim File and had some time today due to weather closures.... so I worked on the Tail Cone. I used my Compound Miter Saw to take a few inches off the tip of the
Conical Nose cone. Took a little bit of trimming of course while trying to ensure it was all square to the blade; to get as straight an edge as possible. The final fit is what I really wanted.

Please let me solicit your thoughts.... anyone with experience please chime in. I want to hide the Slimline Retainer in the Tail Cone. Like the Photos show. It will be Jb-Welded to the Motor Mount Tube, and of course to the inside of the Tail Cone. It is a molded Fiberglass Cone from Public Missiles.
What do you think about heat damaging the cone?


Of Course I could have it extend past the cone about 1/2" but I bought the Slim line for the reason of hiding it...…. Like this:


I am currently waiting for the new Motor Mount Tube as the one in my kit parts is way to short; since my design uses a Tail cone.

 

[Nytrunner]

You should be fine as far as heat goes. I did the same style hidden slimline retainer on Long Tom. JB weld to the mmt, rocketpoxy to blend the lines.

 

[Glasspack]

Thank you, I will press on. I am currently waiting for a centering ring to add to the Tail cone. (I spaced that one off when I ordered the 3.9" Body tube Rings.)
Two days of shut down due to weather . I should have gotten more done on this...……..

I also have to decide if I am going to use the 1515 Rail guides I got by mistake or wait for the 1010 rail guides. I would like to use 1010 rail guides so I can use my own pad.
And I might shorten the 5" long shoulder on the tail cone...….

Thanks

 

[Glasspack]

Starting off slow obviously...… Was able to get some prep work started on the Aft centering ring set and its fit into the tailbone.
Taking off the outer Glassine coat of the tube and getting a good idea where that ring will fit inside the tail cone.



I kind of want to pin the ring to the tail cone using several small flush mounted screws maybe, along with the epoxy to help hold it all together so the motor mount
can better transfer all that energy out to the airframe. The tail cone of course has a nice shoulder and lip to act as a thrust plate against the lower airframe.

 

[Glasspack]

While I am waiting to do some shaping to the aft centering ring to fit the tail cone just right, I decided to work on the Avionics bay. Well, I didn't get far, because my altimeter doesn't power up properly. I tried like hell to find a new 9 volt battery, but couldn't. So went with plan B, my multimeter proved the battery was not the problem as It read 8.8vdc

It only took a minute of troubleshooting to find out the Schurter switch I installed had failed. If I tapped on it after it was turned on, it would eventually make contact. Holy crap its never even flown and it crapped out !!
Well.....better to find out now, than at 4000ft.




knowing it failed even before I ever used it for a flight, makes me NOT want to get a replacement.
I ordered some screw switches from Additive Aerospace.

https://www.additiveaerospace.com/collections/popular-items/products/surface-mount-for-screw-switch

 

[FMarvinS]

Hi Glasspack-Your build looks good! My rocketry warehouse Rogue (98 mm air frame with 54 mm motor mount) also utilized 2 schuter switches (2 altimeters) until both switches failed (fortuitously on ground, not flight). I now use 2 of the same screw switches in 3D printed enclosures which work well on the Rogue. Just one suggestion with these switches, make sure you have enough wire length to remove your avbay from the coupler (when needed) without disconnecting the wired soldering joints on the switches. Also, use JST or better yet, dog house rocketry locking cables to ensure that the cables don't disconnect during flight. For the JST switches, consider adding masking tape around the male-female connecting joint for extra security.

Good luck on the L2.

Fred, L2
ICBM, Camden, S.C.
KG4YGP

 

[Glasspack]

Thank you Fred, the first photo of the Avionics bay in the post above shows the locking connector that allows me to remove the innards of the bay by disconnecting the power switch.
I still cant believe the Schurter switch failed during the build stage.... I hope the Screw switches work well. They seem simpler and thus MORE reliable.

Paul

 

[Glasspack]

The stuff from Additive Aerospace has not even shipped, so I started to work on the rest of the Avionics Bay. I have wire left over from work and chose yellow & brown for drogue charge; and orange & green for the main charge. I want to have all the wire pairs twisted to reduce interference; the drill turned out to work perfect for this task. Carefully secure one end of the pair into the drill chuck. Hold the wires together tightly as they come out of the chuck, slowly pull the trigger and work your fingers down the set of wires. This photo shows two of the sets of wires I did. I inspected the ends and ANY damage found on the tips were cut off before tinning the wires.



I tinned all the wires and tightened the drogue set into the RRC2+. Next was installing the Drogue Charge Well onto the AFT Bulkhead of the bay. My choices for this model came from Doghouse Rocketry. The lower airframe houses the drogue in about 10” of 3.9" dia space. The upper airframe houses the main chute in about 24" of 3.9" dia space. After doing the calculations for the required approximate charges; I used the 1.5g well for the lower airframe (drogue) & 3.0g well for the upper airframe (main). Should leave enough room for the charge, igniter, and packing material. I marked and drilled the holes in the lower lid for the charge well. Installation went well, I used a little piece of heat shrink to further protect the wires as they are secured to the rails. All connections were heavily tug tested.



In the below photo, you can see the skinny studs on either side of the charge well. Those are all torqued and locked down; connected to the eyelets on the underside. They pass the current to the ignitor and use small knurled nuts to lock it down.

I used a piece of shielding over the main set of wires for its amazing protection properties since the upper bulkhead is removable. I installed the main set of wires into the RRC2+ and installed the eyelets for the main charge well. It was going well up to this point …. until...……. I realized I forgot to install a locking connector in the middle; so, I can actually install and remove the bulkhead and the sled.




As you can see from the next photo, I was all set to install the charge well, and hook up the eyelets. At least I figured out my mistake before hooking it all up. The red and black wires on that connector in the photo are for the arm switch that is not here yet.



I will take out the orange and green wires to add the connector tomorrow......

I keep thinking about using forged eyebolts for harness connection; but I wonder if the plywood bulkhead would rip out under stress enough to open the eyebolt. What do you think? The bulkheads are pretty strong.


My tubular Kevlar cord for the Y harness that attaches to the motor mount came in the mail as well. I hope I didn't get screwed over by some hack version...…...

This cord is from "5col Survival Supply" through Amazon. The cord is about 1/4 round braided and rated at 2000 lb. (5col Kevlar Parachute Cord, MIL-C-87129A Type 9 (2000 lb. Min Break Strength))

 

[Speaknoevil]

Looks nice!

 

[Glasspack]

Deleted double post

 

[FMarvinS]

Glasspack-looks very good! I definitely recommend a forged eye nut or bolt-more secure. Also, plywood bulkheads tend to get charred over several launches (black powder effect), you may want to paint the surfaces with auto motor paint to decrease these effects on the bulkheads in the vicinity of your charges. In future builds you may want to use fiberglass bulkheads-they hold up better and last longer.
Fred

 

[FMarvinS]

Glasspack-for the Y harness and deployment laundry, you may want to review crazy Jim's 3 inch punisher build which is "pinned" to the top of the high power rocketry selection column. I and numerous others have used his advice for a guide that has stood the test of time.

Fred

 

[Glasspack]

Glasspack-for the Y harness and deployment laundry, you may want to review crazy Jim's 3 inch punisher build which is "pinned" to the top of the high power rocketry selection column. I and numerous others have used his advice for a guide that has stood the test of time.

Fred

Fred,
Are referring to the harness attached to the motor mount tube ? like this?

I already have plans for that.....Jim was even kind enough to message me back about it.
My last post shows the Kevlar I plan to make the Y harness with.

 

[Glasspack]

Re-worked the avionics bay this afternoon. Took out the wires for the Main charge and redid them with a white and black pair that includes a locking connector.
Had to use a set of eyelets from one of the other charge well kits as its to hard to try and use them once they have been crimped. All the wires were tinned at the solder station and then vigorously tug tested after the connections were made. The two connectors: one for the Main charge well, and one for the power switch that I done have yet, can be seen. I like the idea of coating the bulkhead on the "hot" side once I am ready...… Thank you Fred. I imagine a coat of JB weld thinned out with Alcohol will work nicely.




I have been browsing the web, to find a stainless forged eyebolt to replace the one on the end of the Avionics bay, that doesn't already have the welded one.
Here's my Antares IV Avionics Bay almost all built:



The switch for the red & black wires, should be here in a couple of days.....


I even loaded it with igniters and tested the setup..... wanted to make sure it would report correctly. I will do live testing of ejection charges much later of course......

 

[Glasspack]

The new switches arrived to day, and I had the day off...… so I soldered up a screw switch and mounted it to the switch band.



These screw switches are very nice...….. I really like them. I can see why sooooo many people use screw switches.....Simple, reliable




Also started to unbury my table saw to start cutting out the fins !

 

[Glasspack]

Have a really cool Avionics bay for the nose cone from "Mac Performance Rocketry". Decided to do a little bit of work on that...…
I removed the end of the shoulder so I could access the inside of the cone. I don't know if I said it earlier but I chose the Pinnacle 5:1 Ogive from "Giant Leap Rocketry.
I really like the long ogive and the overall look of this one.

"The forward bulkhead is epoxied to the little ridge (shelf) inside the cone where the shoulder and cone joint is.
​

Of course all the parts are washed and sanded.

I like the Proline Epoxy but boy ….I could really see myself making a mess with this stuff. Have to be more careful.

​

The lower threaded piece is epoxied to the 54mm Avionics bay, then it all gets epoxied into the cone and the aft bulkhead adheres to both the shoulder and the plastic threaded base.
I am modifying this one just a bit to include a slightly longer piece of all thread to allow me to use an adjustable nose weight system. I will cut it to size in a bit.
I might not need it, but the stability on Rocksim is currently only about .60 with my Cert motor.


It is a pretty tall model …. over 90", so well see. I will NOT fly a model with out somehow first verifying its stability. I should be able to get the Table saw out and setup to cut the fins out of my Cotton Phenolic Sheets. I've been toying with the idea of putting holes in the fins at strategic locations and maybe using foam to fill the voids; in an attempt to reduce weight.
Rocksim has this dam thing already at 140oz without the motor !! I really want to reduce that...….. I am trying not to build it like a tank; but I fear my own fears of failure may aid just that !!

Thank you all for any and all inputs …….

Thank you CJ for the conversation !!
Thank you SteveO for the info on your own Nose cone bay !!

Paul

 

[Speaknoevil]

I'm a big fan of the Mac Performance NC Bay's!

 

[Glasspack]

Just got done with the initial cut out of the upper and lower fins. The fin sets are made from 3/16" Cotton Phenolic from Mac Performance Rocketry.

(https://macperformancerocketry.com/...c-sheet/products/cotton-canvas-phenolic-sheet)

I did research the best way to cut it and although I didn't have Carbide tip, I knew the more teeth the finer the cut. But, after a few cuts with my Craftsman Plywood blade......
It really began to dull the blade; so I decided I did not want to continue with it.

Bought an 80 tooth Carbide finishing cut blade by Dewalt, that produced a very nice edge.

(https://www.lowes.com/pd/DEWALT-Precision-Trim-10-in-80-Tooth-Carbide-Miter-Table-Saw-Blade/3730073)


The hardest part was getting the 25 degree sweep angle for the main fins on my table saw; the Miter Guide only goes to 30 degrees.

I overcame that, by using shims clamped onto the guide, so the straight edge of the fin rested against the shims; effectively changing the angle of the other edge of the fin to the blade.
All the tape you see, was holding the three phenolic sheets together tight; so I could cut three exact pieces out.



They still need to be sanded and edged with my router table and fin bevel Jig.
Dam things are heavy though.... 29.5oz for the 3pc main fin set !! and 8.7oz for the small 3pc aft fin set.
I would love to hear any experienced ideas on lightening them, with out sacrificing the integrity of the fins.

Thank you Paul

 

[Glasspack]

Well I have been really concerned with reducing some weight on this thing; so after a nice conversation with Mike at Mac Performance I am going to go with 1/8" thick Phenolic instead of 3/16".
After the math, it came out to about 1.5 lbs of reduce weight in the aft end of the model.....pretty significant.


The aft centering ring is 1/2" thick, made from two 1/4" plywood rings. I plan to anchor it to the Tail cone with small counter sunk or flat head screws, to aid in thrust transfer to the tail cone which in turn transfers it to the airframe, through the shoulder and lip. The Slimline retainer is of course butted up to the Aft centering ring. The parchment paper you see wrapped around the motor mount tube is so that the aft ring will not accidently stick to the tube while the two pieces are glued together symmetrically.
On my day off yesterday I figured out how I was going to shape the aft centering ring to fit nicely inside the tail cone.
To account for the taper; I set up my Dremel table and used a cone bit to taper the outer diameter edge.

 

[o1d_dude]

The stuff from Additive Aerospace has not even shipped, so I started to work on the rest of the Avionics Bay. I have wire left over from work and chose yellow & brown for drogue charge; and orange & green for the main charge. I want to have all the wire pairs twisted to reduce interference; the drill turned out to work perfect for this task. Carefully secure one end of the pair into the drill chuck. Hold the wires together tightly as they come out of the chuck, slowly pull the trigger and work your fingers down the set of wires. This photo shows two of the sets of wires I did. I inspected the ends and ANY damage found on the tips were cut off before tinning the wires.

View attachment 409200

I tinned all the wires and tightened the drogue set into the RRC2+. Next was installing the Drogue Charge Well onto the AFT Bulkhead of the bay. My choices for this model came from Doghouse Rocketry. The lower airframe houses the drogue in about 10” of 3.9" dia space. The upper airframe houses the main chute in about 24" of 3.9" dia space. After doing the calculations for the required approximate charges; I used the 1.5g well for the lower airframe (drogue) & 3.0g well for the upper airframe (main). Should leave enough room for the charge, igniter, and packing material. I marked and drilled the holes in the lower lid for the charge well. Installation went well, I used a little piece of heat shrink to further protect the wires as they are secured to the rails. All connections were heavily tug tested.

View attachment 409201

In the below photo, you can see the skinny studs on either side of the charge well. Those are all torqued and locked down; connected to the eyelets on the underside. They pass the current to the ignitor and use small knurled nuts to lock it down.

I used a piece of shielding over the main set of wires for its amazing protection properties since the upper bulkhead is removable. I installed the main set of wires into the RRC2+ and installed the eyelets for the main charge well. It was going well up to this point …. until...……. I realized I forgot to install a locking connector in the middle; so, I can actually install and remove the bulkhead and the sled.


View attachment 409202

As you can see from the next photo, I was all set to install the charge well, and hook up the eyelets. At least I figured out my mistake before hooking it all up. The red and black wires on that connector in the photo are for the arm switch that is not here yet.

View attachment 409203

I will take out the orange and green wires to add the connector tomorrow......

I keep thinking about using forged eyebolts for harness connection; but I wonder if the plywood bulkhead would rip out under stress enough to open the eyebolt. What do you think? The bulkheads are pretty strong.


My tubular Kevlar cord for the Y harness that attaches to the motor mount came in the mail as well. I hope I didn't get screwed over by some hack version...…...

This cord is from "5col Survival Supply" through Amazon. The cord is about 1/4 round braided and rated at 2000 lb. (5col Kevlar Parachute Cord, MIL-C-87129A Type 9 (2000 lb. Min Break Strength))


View attachment 409204View attachment 409205

Nice work. Neatness counts.

Top marks, sir.

 

[Glasspack]

Edited post #28 to correct Aft Centering Ring thickness