Glasspacks' LVL II Build

Today my beautiful wife and I spent a little bit of time together downstairs; while she was sewing, I worked on my model.
The body tubes are dressed at the edges with thin CA and the Glassine layer came off the Motor mount tube.
You can see the parchment/wax paper around the inverted nose cone to hold the tube fibers neatly compressed and the CA glue sets.

I am still brainstorming the airframe; because the two 34" tubes, the 1" switch band and the longer nosecone; are still not enough to give me the scale length.
I have it upscaled at 102.362" tall; if I use the original metric dimensions (130cm length & 5.3cm diameter) from the SKYTEC Box. So far I am considering a shorter tube for the Fin Can and using a coupler at the FWD Centering ring to stiffen and add a piece airframe tube......giving my the total length I need.






Oh yeah, here is the AFT centering ring I was working on with the Dremel Table, Starting to get a nice bevel to match the Tailcone.

Hi, following your build with interest. Already like the idea of a modified nose cone re-purposed as a tail cone.
I've also been looking at how I might bevel the edges of my fibreglass fins on my current scratch build. I've done a trial sanding on a spare fin for practice and I'm now looking at the Dremel router table accessory to see if that would be better, although I'll need an idea on resolving the angle either with a jig to hold vertical alignment or an angled router bit. I'll await your update on how you go with this task to see how you do it and what I can learn.

BrendanH69 said:

Hi, following your build with interest. Already like the idea of a modified nose cone re-purposed as a tail cone.
I've also been looking at how I might bevel the edges of my fibreglass fins on my current scratch build. I've done a trial sanding on a spare fin for practice and I'm now looking at the Dremel router table accessory to see if that would be better, although I'll need an idea on resolving the angle either with a jig to hold vertical alignment or an angled router bit. I'll await your update on how you go with this task to see how you do it and what I can learn.

Click to expand...

Brendan, This is how I did my other fins....I made a jig for my router table. If you done have a full size router table perhaps, design a jig for your Dremel Table. I built the jig with an 80 degree angle so my fins are 10 degrees each side. The bit is just a straight cut bit. PRACTICE on the same thickness scrap material first !! Plywood does not take a knife edge worth a crap ! Fiberglass may take it much better...…… I like to leave a tiny bit of flat edge you can sand round after your done.

AND ALWAYS REMEMBER SAFETY...…….. ROUTER BITS WILL DESTROY YOUR FINGERS




The edge you want to bevel rests against the table and is clamped securely to the jig. Set and lock the fence to take just about 1/16th off the edge.....Practice with SAME thickness scrap First !!

I KNOW from experience, had to remake a fin after taking to much material in the first fricken pass



These are 1/8" thick Birch Ply fins. I was very pleased with the results:

I plan to use the same jig for my Cotton Phenolic fins....just not sure they will turn out as nice since I am using such thin material.
I got the new sheets Friday... 1/8" thick. ... What am I saying these plywood fins are 1/8" I'm sure the Phenolic will look good as well

Another dam snow day so I was running sims on Open Rocket and Rocksim...……. Trying to get the Rail Exit velocity safely over 50fps yet still keep the altitude down. CERT Flight you know...
Not so easy, I'm finding with this model...…..Also I am finding quite a bit of difference between Rocksim and Open Rocket Simulation data. I have been playing with configuration of fins and stuff to increase performance; but, mostly for Safety !! I don't really like the stability margin much below 1.5 when fully loaded. I do have means built in to add nose weight, but am doing what I can to create this upscale accurately while ensuring stability and safety. Using the original dimensions printed on the box would make this upscale 4.01" Dia and 98.35" tall. That is what I am shooting for.
Some changes include trying it at different lengths by a few inches.....and I have increased fin semi-span from 4.4" to 5" and the FWD fin Root Chord to 17"
I moved my fins aft and kept my longer boat tail The fin slots will be cut into part of the boat tail to keep the exposed part of the boat tail 4.5" as the math works out; according to the original Open Rocket file I have from Argentina. Basically the boat tail length is 4.5" on the upscaled version of my build. My current boat tail is 7" long, to fit and hide the Slimline Retainer very nicely. I originally thought of trimming the tail a bit to match the 4.5" length; but, I moved my fin sets aft to not only keep the 4.5 " of exposed boat tail; but to move the CP aft.

Its still in work and I am just verifying final changes before I cut my fin slots !!

Please any feed back is greatly appreciated !

Beautiful design, and I'm enjoying your attention to detail, especially with the fins.

Thanks Beels,

I had a pretty rough time trying to get a nice bevel on my thin Phenolic Fins this last weekend. Thank god for the scrap pieces to practice on !!
My original method using the 10 degree Jig and the router table proved to be disastrous. No matter how careful I was or which direction the fin was fed.... the ends would chip out way to often to try it on my set of fins. So after much research again ......I really liked "Crazy Jims" fool proof method of using sandpaper on the table with a stop guide and shim piece to elevate the fin, and create the angle as it is sanded by hand. I have 20 edges at least to bevel....So I researched some more...…….. Finally built a new jig for the table saw since I can use the blade to set any angle from 0 to 45 degrees. Determined that 5 degrees works well and found a most satisfactory method using the table saw and the 80 tooth Carbide tip blade. I have a little bit more finish work (like getting the fins to stay put) to do on the Jig then I will post some pics and get some work done.

I would like to thank Tfish38 for some inspiration ………. Holy cow that carpet tape holds the fins on the jig well !!

Glasspack said:

Thanks Beels,

I had a pretty rough time trying to get a nice bevel on my thin Phenolic Fins this last weekend. Thank god for the scrap pieces to practice on !!
My original method using the 10 degree Jig and the router table proved to be disastrous. No matter how careful I was or which direction the fin was fed.... the ends would chip out way to often to try it on my set of fins. So after much research again ......I really liked "Crazy Jims" fool proof method of using sandpaper on the table with a stop guide and shim piece to elevate the fin, and create the angle as it is sanded by hand. I have 20 edges at least to bevel....So I researched some more...…….. Finally built a new jig for the table saw since I can use the blade to set any angle from 0 to 45 degrees. Determined that 5 degrees works well and found a most satisfactory method using the table saw and the 80 tooth Carbide tip blade. I have a little bit more finish work (like getting the fins to stay put) to do on the Jig then I will post some pics and get some work done.

I would like to thank Tfish38 for some inspiration ………. Holy cow that carpet tape holds the fins on the jig well !!

Click to expand...

His jig would slide a lot smoother if he applied some paste wax to the touching surfaces.

I think he mentioned waxing it

Paste Wax...…...Thank You ……….I am going to try that on my new Jig. Although my new Jig is simpler (just a 90 degree brace very much like the other one I built; you can see in the above photo. It slides across the table itself, I hold it tight against the table saw fence.
I am going to try to get my Phenolic Fins Beveled Today or this weekend.

Paul

All I got done this weekend was a whole lot of frustration........ Like I said a line or two ago.....My 10 degree bevel Jig is to small for these fins and I like the 5 degree edge better anyway.
I built a new jig and had absolutely no luck making the bevels look good using my nice 80 tooth blade in my table saw. I could not get straight consistent lines with my table saw and the new jig. The bevel seems to taper off; BUT, it is consistent with the feed direction. Because I flip the fin over to do the other side.. the two bevel lines don't match up at the mating edge. So I tweaked the position of the jig and the cutting blade...….I thought I had it dialed in so I started to bevel one of the small lower fins



Nope. Still not the precision bevel lines I needed
I even tried to do it again on my router table with a higher quality bit and a slower rpm. I was wondering what I was doing wrong...… I was running out of test material !!



This morning I noticed my new jig has a small bow in the face of the board I clamp the fin to. Found out, as the fin even though its clamped onto the board of the jig, as it passes through the cutting media, the fin becomes closer to the teeth at that point of the board because of the bow. It even seems to have a bad edge on the piece of the jig that rides against the fence. Because the fins are so thin already that 1/16" error in "squareness" shows itself well.



Dam it. I should have used Crazy Jims simple, manual, fool Proof method !!! No wonder we all respect and admire that guy !!

Well I have a new jig almost finished (with non warped plywood...……); and its clamped and squared better as it dries. I will get this right... I know I will

Once I do I will redress the one actual fin for the model that you see in the first images...….. Or cut a new fin if it cant be fixed.

Thanks for reading ……
Paul

I dropped the jig option after playing around with it for a while. I went for a simpler home-made 10 degree wooden ramp which I mounted onto my belt sander, then marked up the dimensions and then sanded little, easy and often after that. Not perfect, but pretty happy with it for the straight edges. Hand sanding and trial and error for the double delta leading edges after that.

Photo 1 - Trial piece and a blank

Photo 2 - Sander & 10 degree ramp

Photo 3 - Installed fins

Brendan,

Thank you for the input. The fins you did look really nice. I have thought about one of those benchtop machines......

Tell me do you use it much for rocketry....They are not that costly and I would love to know if most people really are glad they got it ?

Glasspack said:

Brendan,

Thank you for the input. The fins you did look really nice. I have thought about one of those benchtop machines......

Tell me do you use it much for rocketry....They are not that costly and I would love to know if most people really are glad they got it ?

Click to expand...

I bought it just last year inspired for rocketry stuff and then realised I wish I'd gotten one years ago for general DIY stuff too. It was very very rapidly followed last year by a table saw, for the same motivation, and I had a similar realisation I should have done that years earlier too! I've used it to make several rocket related jigs, notably my version of the body tube holder / fin slot router / fin alignment/support combo.

BrendanH69 said:

I bought it just last year inspired for rocketry stuff and then realised I wish I'd gotten one years ago for general DIY stuff too. It was very very rapidly followed last year by a table saw, for the same motivation, and I had a similar realisation I should have done that years earlier too! I've used it to make several rocket related jigs, notably my version of the body tube holder / fin slot router /View attachment 412335 View attachment 412336 View attachment 412337 fin alignment/support combo.

Click to expand...

REALLY nice, Brendan!

Thank you Brendan. I am currently almost done with a new fixture to use with my table saw to shape the fin bevels hopefully with the clean lines I am looking for.
And I am working on securing the AFT most centering ring into the tail cone...…..

My 7/16" Tubular Kevlar Webbing came in the mail last night, so I will try to get that installed soon as I build the Motor Mount.
That is going to make the recovery harness anchor point, secured of course to the motor mount.




The AFT most centering ring was previously tacked into the tail cone so I mixed up some Pro-Line 4500 epoxy and put into a syringe to inject it down onto the FWD side of the ring.
Have to be careful not to get any on the inside edge of the ring, or the 54mm motor mount tube will not make it. The AFT centering ring will be tight against the Slimline Motor Retainer helping to transfer motor thrust to the 1/2" thick ring. That ring is epoxied to the tail cone and will also be mechanically secured to the fiberglass cone with set screws or pins.

Here its upright curing,
The tail cone assembly is the last piece to install after internal fillets and such.. Epoxying THAT assembly to the aft airframe, thus effectively transferring the motor thrust to the airframe. Anyway That's how I see it

Paul

Did a little work on my Antares Model today...….

I have the AFT centering ring Epoxied in place inside the tail cone. I want to help transfer thrust so I drilled and tapped the tail cone and 1/2" plywood ring for small set screws to further aid in the transfer. In theory it will not be an epoxy joint alone that transfers the thrust to the tail cone and thus to the lower airframe.

I have a nice centering tool from DogHouse Rocketry, for drilling into tubes and such...….
So I set out and marked the cone with the location of the Centering ring.... helps make sure you anchor to the right place.
The tool has different adapters for various sizes....I started small and eventually drilled a 1/8 hole in all four spots symmetrically around the cone.

My handy ESTES Tube Marking tool & pencil still works great, although I had to sand the crap out of the pencil to get it to fit. Just taped the stop in place so It didn't move as I went around the cone.
Turned out I found the roll of masking tape worked great to fit snugly around the cone and provided a stop to rest the edge of the drill guide on. And wouldn't you know it happened to put drill guide hole to line right up with my drill marks in the center of the 1/2" ring The dotted line is the edge of the ring.... the drill holes are 1/4" from that... center of the ring thickness.



Once I had all four holes drilled and wiped off, I tapped them with a 10-24 Tap to properly install the set screws. Each hole is of course slightly angled forward to match the taper of the cone, that's part of the beauty of using the drill guide. It ensures the drill bit is perpendicular to the surface, Tapered or straight tube... still effective

More to follow......

Each hole has three drops of thin CA glue to help harden the hole and secure the set screws.

Updated the Open Rocket file a little more...……… I will post the Open Rocket and Rocksim file soon if anyone is interested.
Thought id share this 3D image of my planned LVL-2 Model. For those of you NOT familiar with Open Rocket: The whiteish color cylinders are shock cord pieces,
& the yellow and red discs are parachutes. The aft coupler, which will all be glued in with Tight Bond Wood Glue; allows me to build the fin can much easier & stiffen the lower airframe....
Besides… I needed a way to add enough airframe tubing to reach the upscale length safely.

Please feel free to add some feed back and constructive critisism.

My new Typhoon Carbide Fine Burs came in the mail yesterday from Foredom.

https://www.foredom.net/product/typhoon-tungsten-carbide-burs-1-4-shank-tapered-shapes-coarse-or-fine-priced-ea-copy/

So far my first test pieces of 1/8" Hardboard are proving to be pretty nice. They definitely leave lines in the material like Others have stated.
But that can be taken care of when final sanding with 150-250 grit paper

Thank you again to Steve (Hooked on rockets) for chatting about your experience.

I got the two blue Fine Burs on the Left in the image.... I am liking that long taper so far...… Will try it on the Phenolic next



Here is just the very first test with the Typhoon long Tapered Fine Bur...……..
Got to remember to keep pressure against the Router Fence.... I shot one of the pieces across the garage !!


Well we will see how the actual Canvas Phenolic fins turn out soon enough...……….

Well I found out soon enough that my router table is a piece of Sh..! The test pieces ran through the Typhoon bit ok, as well as the smaller AFT fins........
but the long FWD Fin set proved to be problematic for my table....... The fins seemed to get caught on the center insert on the table, or the slot for the fence T-bolts. Each time it happened the fin jumped ever so slightly....but with 1/8" material it doesn't take much to leave a BAD mark.....


My dumb ass even made one pass across the bit with the root edge of one of the fins by mistake !!

I share my failures as well as my triumphs ............. I since laid down a new piece of hardboard over the top and brought the bit right up through it, eliminating all chance of catching edges again. So I will trim the fins a little and run them through again. Or Cut a new set of FWD fins and try again.

Impressive angle on the bits you bought, might need to try those out!

i do like the long bevel edge.......... If only I took smaller passes and had a SMOOTH Table Surface !!!

Nice work! I just bought a small hand held router and I like it so far but really should get a table I can mount it to...

SDramstad said:

Nice work! I just bought a small hand held router and I like it so far but really should get a table I can mount it to...

Click to expand...

You might want to consider building one. I used Router Magic and another Router book to put together my table. The top is pretty standard, but the cabinet was very cool. The front door to give access to the router has a 3/8" gap along the bottom. Then there is a panel about 2" from the back panel that seals the back except for a 1/2" gap on the bottom creating a plenum along the back. The shop vac hose connector is on the back panel and it sucks the air under the front door, across the bottom and into the plenum. Between that and the air moved by the router cooling fans, there is never any sawdust left inside the table when you are done. Just that design was worth the cost of the books...

Handeman, I found out the hard way how important it is to have a GOOD Table Top to try and Bevel the fin edges with a router. When I did it for the 1/8 Plywood I had no problems. This Phenolic is much harder and my table has since worn out more, I guess. The edges of the work should NEVER bind on any edge of the table or inserts. But you see the results (above photos) of catching an edge...…

I received two new router bits in the mail today another FINE "Typhoon" style bit from Saburrtooth, and a Tapered Carbide Spiral cut bit.

This one is basically the same as my Blue one

I really wanted to give the tapered bit a try. First I had to dress up my router table to avoid the edges I caught last time !!
I used a piece of 1/8" Hard Board right on top the table surface to eliminate any edges, then raised the cutting bit right up through the hard board atop my router table. I used a piece of heavy MDF to improve my fence, got a much nicer feather board and proceeded to redo my fin edges.

View attachment 415348 This is a much smoother set up than before - Same table though

I cut 1/2" off the leading edge of the three fins..... Stood them all on the root edge, on the table saw, tight against the fence, made sure they were square and clamped them together. I then wrapped them tight in clear, wide packaging tape. It works great to hold them all together for cutting on the table saw; since you cant cut them with a clamp attached. Duh. It changes the size of the fins just a little, so, I will start updating the Rocksim file and make any needed adjustments to ensure safety of stability and such. OR I still may cut a new set...……

I used the Amana Spiral cut tapered router bit this time, Not as steep an angle (6.2 degree), but it gave very nice results. And a smoother cut than the Typhoon bit. Its made by Amana, I got it from Amazon.

View attachment 415350

Anyway..... The cuts were made a little at a time on each fin, & each side, BEFORE adjusting the fence closer.
The edges turned out pretty nice, there are still a bit of the scars from earlier but I still have to sand the entire fins so I think it will be ok.


I still have not cut the notches in the root edge to create the "through the wall" fin tab, but I am happy with the edges.
Yes they are sized to allow a 0.7566" tab for the 54mm motor mount tube.
I may still use these, or cut a new set; now that I can get a nice edge on a set of fins again !!
If I do use them, I don't even think it will look bad with the trailing edge a deeper bevel than the leading edge.

I really wanted to do this myself...…..but this thin Phenolic comes with some challenges, next time I may save the headache.
DEFINITELY worth it to pay MAC Performance to bevel them !! That store is awesome by the way !! https://macperformancerocketry.com/

What do you all think ??

I agree-I've mostly used the Typhoon bits on 3/16th G10 fiberglass fins. The extra challenges arise when using "softer" materials (e.g. plywood). MAC does great work so I agree in the future for his fin stock, I'd use his service.

Fred, L2
ICBM, Camden S.C.
KG4YGP