Glasspacks' LVL II Build

[Glasspack]

I am not very fast on this build that's for sure. Had some time between a sick day and fixing some plumbing fixtures.
I had new Phenolic sheets coming in the mail, so I could cut a new set of FWD fins but that package got lost in the mail...…
It was in New York on the 8th and it hasn't been updated since. That help make the decision for me to use the original fins after I trimmed the bad parts of the bevel and re-bevel them. I reworked the Rocksim and the Open Rocket files with the slightly shorter FWD fin set and still have over 5 calibers of Stability with out the motor. Even the longest motor I plan to fly still gives me 2+ calibers of stability.....so that's good. I really done think I will need the provisions I made for Nose weight adjustment. Still have to trim the centering ring at the aft of the airframe tube, it will have to fit just inside the shoulder of the tail cone to allow the aft fin set to but up against it. Still not sure how I cut the notch in the fin tab to far back from the tip.


So here is how I did the final trim of the Aft Tail Cone...…. The Slimline retainer was dry fitted to the 54mm Motor mount tube and inserted tight up against the Aft centering ring. Then I measured with my caliper how deep it sits inside from the end of the cone. Marked the cone at THAT measurement to make the cut. Very important to get a square cut on a tapered (Conical) tail cone. I have a 90 degree jig for my table saw fence for various things..... I secured the tail cone into the aft airframe and then secured that assembly into the jig.


The Compound Miter saw works perfect for this type of cut.



Very happy with the results...……… Here is what the final assembly will look like. The retainer is hidden inside the tail cone, just like I wanted.



So I was hoping if I posted the Open Rocket file I could get some feed back for all you more experienced builders & fliers.

I am building the AFT airframe using a shorter tube so I can do the internal filets and fin securing a bit easier. PLUS, I am thinking the coupler added just FWD of the fin set will help stiffen the airframe and help to keep the airframe from crumbling from Air load stress !! I already know Cardboard models have made Mach 1 flights.

Thank you

Paul

 

[Glasspack]

 

[OverTheTop]

I inspected the ends and ANY damage found on the tips were cut off before tinning the wires.

Did you tin the ends that go into the terminal block? Bad idea if you did. The solder creeps under pressure and the pressure comes off the connection. Either use stranded straight into the connectors if you have connectors with the nice plates that protect the wires, and/or use bootlace ferrules on the multistrand to protect it.

Also, when tinning multistrand wires remember that where the solder stops becomes a stress point for vibration and movement. Support the wire until past that point for reliability.

Looking good so far .

 

[BrendanH69]

I am not very fast on this build that's for sure. Had some time between a sick day and fixing some plumbing fixtures.
I had new Phenolic sheets coming in the mail, so I could cut a new set of FWD fins but that package got lost in the mail...…
It was in New York on the 8th and it hasn't been updated since. That help make the decision for me to use the original fins after I trimmed the bad parts of the bevel and re-bevel them. I reworked the Rocksim and the Open Rocket files with the slightly shorter FWD fin set and still have over 5 calibers of Stability with out the motor. Even the longest motor I plan to fly still gives me 2+ calibers of stability.....so that's good. I really done think I will need the provisions I made for Nose weight adjustment. Still have to trim the centering ring at the aft of the airframe tube, it will have to fit just inside the shoulder of the tail cone to allow the aft fin set to but up against it. Still not sure how I cut the notch in the fin tab to far back from the tip.
View attachment 416268

So here is how I did the final trim of the Aft Tail Cone...…. The Slimline retainer was dry fitted to the 54mm Motor mount tube and inserted tight up against the Aft centering ring. Then I measured with my caliper how deep it sits inside from the end of the cone. Marked the cone at THAT measurement to make the cut. Very important to get a square cut on a tapered (Conical) tail cone. I have a 90 degree jig for my table saw fence for various things..... I secured the tail cone into the aft airframe and then secured that assembly into the jig.
View attachment 416265

The Compound Miter saw works perfect for this type of cut.
View attachment 416266


Very happy with the results...……… Here is what the final assembly will look like. The retainer is hidden inside the tail cone, just like I wanted.

View attachment 416267

So I was hoping if I posted the Open Rocket file I could get some feed back for all you more experienced builders & fliers.

I am building the AFT airframe using a shorter tube so I can do the internal filets and fin securing a bit easier. PLUS, I am thinking the coupler added just FWD of the fin set will help stiffen the airframe and help to keep the airframe from crumbling from Air load stress !! I already know Cardboard models have made Mach 1 flights.

Thank you

Paul

Looking good! Compound Mitre saw next on the tool shopping list!

 

[Glasspack]

Did you tin the ends that go into the terminal block? Bad idea if you did. The solder creeps under pressure and the pressure comes off the connection. Either use stranded straight into the connectors if you have connectors with the nice plates that protect the wires, and/or use bootlace ferrules on the multistrand to protect it.

Also, when tinning multistrand wires remember that where the solder stops becomes a stress point for vibration and movement. Support the wire until past that point for reliability.

Looking good so far .

Thank you Over The Top,

I did in fact tin all the wires that go into the terminal blocks. I can add some tracers of RTV to support the wires around stress points and I can also redo the connections in the avionics bay......

 

[OverTheTop]

If you don't want to redo the connections you can just nip them up before each flight.

 

[Glasspack]

I was able to get some work done today before work. I had previously marked the aft airframe for fins and rail guide yesterday. I finalized the measurements for setting the aft fins into the tail cone to reduce the exposed cone length to closer match the upscale. The AFT fin slot is 4.125 inches long and goes into the tail cone 2.25 inches. The FWD fins have a tab that's 12 inches in length and the distance between the fins is about 2.125 inches.

So I marked the entire tube, and set up the slot machine. The double hash marks are so I can put the tail cone back in correct orientation every time I remove it during the build, and then for final assembly.

The 1/8" Router bit did not cut a very clean hole in the card board tube, so I have some clean up to do; but I expected that.
It was nice to be able to help visualize the whole thing for the first time other than an image.











That aft edge of the main fin will be filled and cleaned. It will not be noticeable when I'm done.
That was one of the marks from my dam router table incident.



That stubby version was to include the nose cone. Just for a fun shot...…….

Anyway I was happy to make some progress on it again. AND.......Got a new notification from the Post Office.
My new Phenolic Sheets are finally back on their way to South Dakota form the East Coast.

Oh well, I committed to cleaning these fins up and using them !!

 

[OverTheTop]

Looking good.

You can fly the stubby version if you set it up right. I have done that with my Velociraptor.

 

[Glasspack]

I got started on some work since I have a four day weekend. The Fin Can/Motor Mount assembly will be built outside the airframe and then slide up into position for final gluing. Noticed during test fit that the fin tabs are not deep enough by about 0.010" so I clamped them together tight and square, then taped them all together with clear packaging tape and added a piece of masking tape across the root edge to marked them. My Dremel tool and a rotary cut off wheel worked well, to go through all three fins at the same time.




The Lower Airframe section is designed to be about 22" long coupled and epoxied to the to the Middle airframe to allow for the length of the model while allowing ease of internal fillets and adding strength the airframe. You can see the cut line in White paper edge under the masking tape. I used the compound miter saw to cut the airframe tube to size. There was a sacrificial coupler inside to help give me a cleaner cut.





Its only Sunday...……… I have the rest of today and Monday to do some work on it...……….

 

[Glasspack]

The fins were sanded along the root edge with 60 grit paper, to rough up the material for bonding, then the entire fin was sanded with my mouse sander and 220 grit to prep them for filling and finishing.



Yeah that's fricken' tape holding the battery in my sander...… ….all of my Nextec batteries have broken tabs and fall out of the tools.

After sanding and cleaning up the dust I wiped them all off with Denatured alcohol and let them dry...… Then tacked the FWD centering ring in place while it was in the airframe and butted up against the fin tabs. That ring was tacked with quality wood glue since its cardboard to wood. The material will fail before the glue joint comes apart.

I Had to change the design length of the 54mm Motor Mount tube to 25.5" due to the final overhang once the FWD Centering Ring was secured in place.
I now have just 0.25" of the tube sticking out the front, (instead of 0.5") just enough to add a fillet, AFTER the Mid Airframe coupler is glued in place tight against it. I will also add the Recovery Harness anchor to the tube after the fins are all tacked. Tacked one of the fins with CA after cutting the 54 mm Motor Mount Tube down to size. Not sure if my glue is messed up or not but, it took a very long time for the CA to cure an even remotely secure the fin.



So I mixed up a tiny bit of Proline 4500 and tacked it that way !!


I will get them all tacked and secured with the internal fillets and get back to the post !

 

[Glasspack]

So now that two of the fins are tacked to the motor mount tube...……….
I grabbed the third fin to tack it on, and I also grabbed the Plywood Fin Alignment Plate.
Most of you know what kind of plate I'm talking about...…..

Like this one.....




You ever do something and then wonder WHY THE HELL you didn't do that to begin with ???
Well just a got a major set back...… I put the jig plate up to make sure the fins were in the right spot and realized the first two are not exactly 120 degrees.
look at the off center gap of the jig in this picture...…..
AND …….To make matters worse !! The slots I cut are not lined up very well with that same fin Jig plate. I used a printed fin guide on a piece of paper to mark the 3 fins & Aluminum Angle to put lines on the tube. NOW I realize, should have used the guide with the aluminum angle to ensure the slots were exactly 120 degrees apart as well. I could have made it work since I was able to cut the last fin off the 54mm tube with an X-acto knife and two blades to cut through the epoxy joint. The slots would have to be widened but, then the aft fins would be off as well since they were cut on the same lines...…. Those slots also would have to be widened.

FRUSTRATED !!!!! I am going to use another piece of airframe tube, since I have several; and pick this up again later.

Here are the new fin lines I made on the other section of 4.01" airframe ….



I think I will just use the Aluminum angle and cut the slots by hand with an X-acto blade or two...…. I am so DISSAPOINTED IN MYSELF !!!

 

[mbeels]

I've done worse! But your attention to detail here will make a really nice rocket in the end.

 

[Glasspack]

Mbeels, Thank you for your Support...………….

I was very upset at myself, but was very encouraged by your comment !! Thank you !

I got home from a dinner party tonight and started right away.
Went back to old school methods and put together a cutting jig for the High Power Cardboard Tube airframe pieces. I started with a 34" section to make the new Lower Airframe.

Had to make a new section 22" long ……… This thing worked GREAT ! The paper trick for the very straight line and the Razor Blade for the nice cut !
The Jig is a 90 degree frame with a stop block clamped onto the work bench at the other end to keep the tube from moving out of the desired measurement. The fixture is also clamped to the table so it cant move. The brand new razor blade is screwed to the handle. A little bit of pressure on the handle as the Tube is rotated towards the blade, slowly but smoothly cutting a VERY nice edge.



There was also a coupler under the cut to help make it a clean cut. Both ends were later sealed with Liquid CA and I am pressing forward !!




That turned out a much nicer cut than did my miter saw ……….My tail cone will fit nicely up to that edge when I epoxy it in place !

Thank you all for watching...…….I wish I had the skills Crazy Jim or John Coker have !!!!

GOD Bless and Happy Memorial Day !!

 

[Nytrunner]

Very unfortunate!

Do you think there was a scaling error when you printed out the guide.

 

[Glasspack]

No scaling error.....its a paper I've had for a long time. Its just lines on a paper with differant tube sizes.

Basically the Estes guide on a piece of paper....... Just made marks on tube, then used aluminum angle to draw lines...... Should have used a more precise method.

 

[Glasspack]

No scaling error.....its a paper I've had for a long time. Its just lines on a paper with differant tube sizes.

Basically the Estes guide on a piece of paper....... Just made marks on tube, then used aluminum angle to draw lines...... Should have used a more precise method.

Paper version of this.......

 

[rfjustin]

So do you prefer Foredom bits or Saburrtooth?

 

[Glasspack]

So do you prefer Foredom bits or Saburrtooth?

So I haven't actually tried the Saburrtooth bit ....it looks so much like the Foredoom one I have but its yellow instead of blue. I didn't like the spiral cut one I have, It did a nice job but I like the longer bevel edge that the other bits provided. I will let you know if there is a difference between the Foredoom and Saburrrtooth

 

[rfjustin]

So I haven't actually tried the Saburrtooth bit ....it looks so much like the Foredoom one I have but its yellow instead of blue. I didn't like the spiral cut one I have, It did a nice job but I like the longer bevel edge that the other bits provided. I will let you know if there is a difference between the Foredoom and Saburrrtooth

Please, and thank you.

 

[Nytrunner]

didn't like the spiral cut one I have,

Fascinating, I'd think the spiral would help even out the gouges, but I defer to empirical data

 

[Glasspack]

Fascinating, I'd think the spiral would help even out the gouges, but I defer to empirical data

It did even out the and minimize the gouge for the parts of the bevel that were redone cut after trimming the leading edge down a bit.
Here are the best three sides.......... Its not as wide a beveled edge due to the angle of the bit.


Those 5 degree burr style bits work well when you don't screw up the pass across the bit !!!



I've since modified my router table top a bit to eliminate any spot that could catch a fin edge as it slides across.
Hell since I made the big screw up on my Lower air frame and had to cut a new section .....
I may just cut three new fins !!!

But, I feel I can make these work well...... just have to fill a little bit to fix the gouges and make em pretty

 

[Glasspack]

So I've recut, re-slotted & reassembled the new 22" Lower Airframe section. Then test fit the fins using the Fin guide to check. MUCH nicer !!







NOW....I am going to solicit YOUR help (Your Opinion really)…….. You can see how "off" my first slots were..... In the below photos, you can see the original slots cut into the white tail cone. If I line up ONE of them to the new AFT fin slots; this is how far off the other two are:


This slot lines up to the new AFT Fin slot lines...…..





This is how far off the other two are...…….Give or take a 1/16" of an inch


SO...… I would like your opinion..............and your experience.
I can use the tail cone I already made and widen the two slots I need to ……then fill in, and shape it. Ultimately hiding it with the epoxy fillet .

Or... Should I get a new cone and rebuild it.
Thanks


I am going back to the model to put on the recovery anchor.

 

[Speaknoevil]

I would just make the existing tailcone work.

 

[BrendanH69]

New fins and body look good.
I tend to agree with Speaknoevil - make it work without re-starting the tail cone.
If tail weight of the added epoxy is not an issue for you and if I'm right in thinking that in your design the tail cone isn't intended to be removeable, then I would go with your first suggestion to widen out the tail cone slots and fill in several stages with thickened epoxy. You may have intended to drill a few holes in the body tube and tail cone to inject internal fillets, so widening the slot is just...well.. a bigger version of that!

 

[Speaknoevil]

New fins and body look good.
I tend to agree with Speaknoevil - make it work without re-starting the tail cone.
If tail weight of the added epoxy is not an issue for you and if I'm right in thinking that in your design the tail cone isn't intended to be removeable, then I would go with your first suggestion to widen out the tail cone slots and fill in several stages with thickened epoxy. You may have intended to drill a few holes in the body tube and tail cone to inject internal fillets, so widening the slot is just...well.. a bigger version of that!

Actually, shouldn't add much weight to fill the fin slot gaps. Use some thick epoxy (filled West or RocketPoxy), push the minimum amount needed into gap and apply an adhesive fiberglass tape, then some vinyl tape. Turn over and let settle into the gap. After cure you will have a nice smooth fill with the minimum amount of added weight.

 

[Glasspack]

Thank you all for your thoughts. Your right ....only two of the slots have to be modified.
I will press on with the build and not spend the $65.00 for a new piece to make a new tail cone.


Last night I had dry fitted everything and was trying to decide which fin guide to use..... My holding jig that I made to lay up one fin at a time along the airframe axis. OR The Laser Cut Plywood all 3 fins at once guide.... When the whole thing fell off the work bench onto the floor and broke a fin tip and the plywood guide. I took that as a sign from the Rocketry Gods to call it a night !!!

This morning I tacked the fins to the motor tube …………. I never did get the recovery harness anchor put on yet.... that's next after I pull out the fin can assembly from the lower airframe; after the fins set up for a few hours.

If you zoom in , the fin on the left has the tip missing...……
I will epoxy that in place once the entire motor mount /fin can is done.

 

[Glasspack]

New fins and body look good.
I tend to agree with Speaknoevil - make it work without re-starting the tail cone.
If tail weight of the added epoxy is not an issue for you and if I'm right in thinking that in your design the tail cone isn't intended to be removeable, then I would go with your first suggestion to widen out the tail cone slots and fill in several stages with thickened epoxy. You may have intended to drill a few holes in the body tube and tail cone to inject internal fillets, so widening the slot is just...well.. a bigger version of that!

Your correct Brendan, The tail cone assembly is almost the last piece to be added to the motor mount/lower airframe. It will be epoxied in at the same time the Slime line retainer gets JB welded in place.

 

[Glasspack]

Finally got the fins attached to the motor mount today, also put in the recovery harness anchor. The little block of ply wood in the last photo is the upper rail guide attach point. It will be also be glued to the inside wall of the airframe and the guide screwed into it, through the airframe. The lower one looks just like it, but 1/4" shorter.




I had a few frustrating accidents with it as it fell twice to the floor. Now I have two fin tips damaged...… and a ding in one trailing edge......
It hasn't even fricken flown !!!!
I wanted so bad to have NICE phenolic fins !!!
I have a lot of finish work ahead of me to make this look nice !!!
Got to figure out what I can put behind that block, light weight, that will help hold it against the inside of the airframe as I drill and mount the Rail guide. Maybe the Proline 4500 is enough..... I had already glued the middle centering ring behind the FWD fin set so I can't reach in with a long stick to put it in later......

 

[Glasspack]

Well here is what I came up with to ensure that Plywood piece stays against the inside wall of the airframe as I drill and Mount the FWD Rail Guide

Think it will work fine ………
Going to work on cleaning the fins today and getting the motor mount assembly epoxied into the lower Airframe.

 

[wsume99]

Well here is what I came up with to ensure that Plywood piece stays against the inside wall of the airframe as I drill and Mount the FWD Rail Guide

Think it will work fine ………View attachment 419215
Going to work on cleaning the fins today and getting the motor mount assembly epoxied into the lower Airframe.

Interesting idea. I normally just glue it to the ID of the airframe. In this case I'd have put it ahead of the FWD CR and installed it before inserting the MMT.