Wayco's Ultimate Darkstar build

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Started building the avbay yesterday. I received a sheet of black G10 fiberglass from Wildman last week, cut to fit the 18" coupler. I cut out a spot on each end to clear the nut and washer holding the forged eyebolts at each end.
004%205.jpg


The sanded patch is for my custom built battery holder. I glue 1/2" strips of plywood down to hold the batteries in place:
008%205.jpg


Glued it all together with Rocketpoxy and clamped it down to cure.

Then I cut a strip of G10 to hold them down, with short pieces glued on to reinforce where the screws go:
009%205.jpg


Had to make a run to ACE Hardware to get some 1" long 8-32 stainless screws to finish it up.
Used my neighbors drill press to get the holes through all the layers, and mounted pem nuts on the backside to screw into.
Perfectflite sells 4-40 standoff's, and I use them for mounting all my altimeters. Here is the finished sled:
016%206.jpg


I mounted my favorite terminal blocks on the avbay lids. This is an older kit with the fiberglass bulkheads glued together for the lids, which is nice when you do it like I do:
014%206.jpg


I use 24 gauge stranded copper speaker wire for all the terminal blocks, run it through the holes in the lids and solder it to the blocks, then put a spot of hot glue under them and push them down before it cools.
I'm using the large Dog House ejection cups, which hold 6 grams of BP. I drill and tap the lids for the 10-32 screws that hold them down, and cut off the excess screw on the inside to avoid interfering with the sled. My sled is not attached to the all-thread rods, it is sandwiched between the avbay lids and held in place when the lids are tight. Here is how the lids look when done:
003%204.jpg



 
Couple questions - what size is that all-thread, 1/4-20? Also. What size eye bolts are you using? Looks good so far!
 
GMTA !

Except i use nylon 4/40 stand offs , and usually do tNuts . And have started putting the chanel back on the sleds ..not to hold it down but it helps with wire routing to keep clear where the all thread comes through.

That is a BIG sled !

Kenny
 
Worked a bit more on the avbay today, cut down the 6" switch band to 2" and drilled out the holes for my rotary switches. I decided I didn't want to twist and tape while standing on a ladder because it takes two hands, so I dug out some Schurter rotary switches. Drilled 1/2" holes through the switch band and the avbay, removed the switch band and enlarged the holes so the switch would flush mount, and put it all together. I fit the avbay into the fin can and rotated it around for the best fit, which wasn't very good. So I removed it and sanded down the band on a piece of 80 grit sandpaper that was taped to a flat surface. It took several attempts at this before I got it flush all the way around. Once I had it fitting properly, I took it all apart, sanded the band and the area on the coupler where it would fit:
002%205.jpg


001%205.jpg


Mixed up a small amount of Rocketpoxy and glued it together, then set it outside to cure.
Since I used up all my 24 gauge speaker wire on the terminal blocks, I set the avbay aside and started putting the recovery parts together. Wildman sells some really nice 3/4" red tubular nylon and we bought some last year at Airfest. Enough to rig both my Ultimate DS and Sharon's Gizmo XL. I'm using 40 ft. of it for the drogue, and sewing together a pocket to hold it all and a Skyangle 24" drogue chute. I ordered a 60" Nomex cover today for the end that fits to the avbay. Here is what I got done:
004%206.jpg


003%205.jpg


The other shock cord is for the main chute. I ordered a big Nomex pad to wrap the Skyangle XL chute into, and will be working on this project later this week when my parts come in.
 
Yeah, the all-thread and eye bolts are both 1/4-20. Got that advise from some crazy guy that went banana's on his Ultimate...

Great looking build Wayne. Always learn something new from them. I am wondering if the single 1/4-20 eyebolt on a fiberglass bulkhead is beef enough for a rocket this heavy. Is the backing washer 1"? The reason I ask is even on my 4" Broken Arrow, I have some angst about all the concentrated shock cord stress at that single point maybe pulling the eyebolt thru a fiberglass bulkhead. Probably just paranoia, but I am wondering what you and others think on maybe a y-harness to the threaded rods.
 
Great looking build Wayne. Always learn something new from them. I am wondering if the single 1/4-20 eyebolt on a fiberglass bulkhead is beef enough for a rocket this heavy. Is the backing washer 1"? The reason I ask is even on my 4" Broken Arrow, I have some angst about all the concentrated shock cord stress at that single point maybe pulling the eyebolt thru a fiberglass bulkhead. Probably just paranoia, but I am wondering what you and others think on maybe a y-harness to the threaded rods.

We share that concern. I talked to CJ about this, and he reminded me that the 550 lb. rating on that eyebolt is a "working load" rating, and it can withstand a much higher load. I do have a 1" washer backing it up too.
I know that there are a few of these rockets out there, and would like to hear from other fliers regarding this.
 
I am wondering if the single 1/4-20 eyebolt on a fiberglass bulkhead is beef enough for a rocket this heavy. Is the backing washer 1"?.


6 built fiberglass rockets. [6in diameter] I built all.

2 mine.... all use 1/4-20 hardware. Yes with 1in washers.

Flown:

6N's including 2-N-10,000.......N-5800....N-1000.....N-1100

14 M's .....8-L's and many others I can't remember.

1 built in 2003 still going strong. {my L-3}

NO hardware failures in any of them
A simple question to all......have you done it?:wink:
Works for me, I don't overbuild by design. More glue, more metal, more G-10 = more weight and stress =needing larger recovery gear.

As I have always said.....if it makes YOU sleep better , use bigger stuff, nuff said.

PS one was pulled out [attempted] of a tree by attaching the 1in. 4500lb test TN to bumper of truck. shock cord snapped clean, eyebolt never bent or pulled though BP. :grin:
 
I hadn't heard the one about pulling a rocket out of a tree with the truck, but CJ is my "Main Man" for info. on building big rockets, and I don't know anybody who builds or flies more than he does.
I spent a bit of time working on shock cords and another "deployment bag" for the tubular nylon I'm using on the Main chute shock cord. I got in my shipment from Top flight, which included shock cord protectors and a 24"x 24" pad for the Skyangle XL chute.
Drilled the static ports for the avbay, three 5/16" holes. I will post up pic's tomorrow, it's almost bedtime here.
 
We share that concern. I talked to CJ about this, and he reminded me that the 550 lb. rating on that eyebolt is a "working load" rating, and it can withstand a much higher load. I do have a 1" washer backing it up too.
I know that there are a few of these rockets out there, and would like to hear from other fliers regarding this.

First off - I absolutely agree with you and Jim that what actually works in real practice is what matters. If Jim (and others) have flown a particular configuration dozens or hundreds of times with success, than by design that configuration simply works.

That said - one minor quibble regarding understanding "working load": Yes, most any hardware and such can withstand much higher loads than their stated "working load". But this does NOT mean that it is always safe or wise to do so. This is because when a working load rating is given for a particular component, it is done so with the understanding that the load is at rest. Once you add momentum/motion to that load, the actual load on the system or component goes WAY up. I used to do a fair bit of mountaineering (and "industrial" climbing as well). Some people would wonder why my ropes/carabiners/etc. were rated in the thousands of pounds. Why would I need anything rated stronger than say about 200lbs in my gear? - if I weighed 160lbs, that ought to hold me just fine, no? Well a 160lb. body falling just 10 feet would snap that component like a pretzel of course, and I would likely fall to my death.
If something is rated with a "working load" of 550lbs, it is done so assuming a reasonable expectation of motion that that 550lbs might be subject to - which generates a whole lot more than 550lbs. of force. And hence, something that is rated at 550lbs will hold a lot more weight - IF that weight is not moving.

But again - what works in practice for us is what works. I completely trust Jim's experience, and if he says it works, I'd be comfortable with that.

Great build and thread Wayne, as always,
thanks for sharing it with us,
s6
 
Just ask yourself about diminishing returns. Is a 5/16-18 eyebolt going to penalize you considerably in the weight or space department? What additional advantages does the increased size get you? Even if it makes you "feel" a little better, it's probably worth it.

Personally, I'd go to a 5/16" u-bolt on the apogee side. If you watched the onboard video of my Proteus from LDRS this weekend (I've posted it a bunch of times all over, so I'll save from spamming more) you'll notice these larger rockets with big spans can spin quite considerably on the way down. I'd be VERY concerned with unscrewing that tiny little eyebolt. I used a 5/16" u-bolt and used two quick links to prevent it from separating. My Competitor 5 managed to spin up and actually undo the quick link, dropping the booster at 8,000'. There were indications on the quick link's hex nut and the u-bolt from the repeated hammering.

I wouldn't consider increasing the eyebolt's size "overbuilding." I'd consider it a prudent upgrade.

IMG_2245.jpg
 


I went to that thread and noticed something when I enlarged the picture of the failed eye bolt. The bottom picture shows it the best, the whole thing is bent across the length, caused by shear force, it wasn't meant to be used that way. When I looked at it closer, I noticed that it was like one I have and did not use, it was poorly made in China. I pulled it out and took a picture of it next to the American made ones I get from McMaster-Carr:

044%202.jpg


The Chinese one is not flat where it seats against the bulkhead and can rock back and forth, even when tight. The metal looks porous, and the threads are rough. The American made one is thicker in the eye, and larger overall, and the threads and base have a much better finish.
Like I said in that thread, you can destroy anything with enough mass and momentum. The owner of the rocket said that the failure occurred during or at the end of boost, so there were other factors involved. No matter how conscientious we are with our builds, when the "stuff" hits the fan, it's always good to be a long way away, that's why we put the "Large, Dangerous rocket ships" way out there. 'Nuf said.

Yesterday, I supervised Sharon while she started work on her L-3 project, using a drill press for the first time to drill holes in the aft centering ring of her 8" Gizmo XL for the 98mm aeropac retainer. She should be starting her build thread soon.

Here are the pictures I promised to post up of my avbay switches:
040%203.jpg


Not perfect, but that's my first attempt to recess the rotary switches into the switch band.

My least favorite part of a build is drilling holes, especially in filament wound fiberglass. But there are a bunch of them, and I started on that yesterday morning also. I drilled six holes, three to hold the payload to the avbay and three more to hold the nosecone to the N/C coupler. All of these will be countersunk on the outside, and have pem nuts pressed into the inside of the coupler.
I have covered this before, but since I really like pem nuts, and have a simple method to insert them, I'm going back over it now.
First, you want to drill a straight hole with as little fraying on the inside as you can manage. I do this by applying my favorite sticky green masking tape to the inside of the avbay where the drill will pop through:
017%206.jpg


Then I have a large diameter PVC pipe to back it up:
016%207.jpg


Slide the payload tube and avbay onto the pipe:
018%205.jpg


And drill down through the tube slowly, while pressing down on the tube:
023%204.jpg


I'm using 8-32 flat head screws for this rocket, and drill my initial holes with a 5/32" drill, just large enough to screw into and hold the parts together while I drill the next hole. One hole at a time, adding another screw to keep everything in line. When I finished the avbay/payload, I repeated the process with the nosecone and it's coupler. Now I take it all apart and re-drill the inside holes to 1/4", which is the correct size for the 8-32 pem nuts. Be careful drilling the larger holes, if you go too fast it will pop through and fray the filaments despite the tape and pipe backup.
To install the pem nuts, you need a longer 8-32 screw, a nut and a couple of washers. The top washer should fit the screw, the bottom one should have a larger inside diameter to clear the pem nut as it pulls in:
035%203.jpg


Stick the screw and stacked washers through the 1/4" hole and screw a pem nut on from the inside. Hold the screw and tighten the nut until the pem nut is snugged up into the tube:
037%203.jpg


It was starting to warm up by the time I had all the holes drilled, so I took everything into the epoxy/laundry room to insert the pem nuts and countersink the payload tube and nosecone:
038%203.jpg


Here's what it should look like when you get it just right:
039%203.jpg



I also worked a bit more on my recovery, packing the Skyangle XL chute in my new 24" x 24" Nomex pad I got from Top Flight.

009%206.jpg


I always start by laying everything out with the nosecone end on my right and the payload tube/avbay on the left. I put the first wrap of the pad around the chute and pull it tight:
010%206.jpg


Then continue to wrap the shroud lines in, separate from the canopy:
011%206.jpg


Next, I pull the open ends together, paying particular attention to the left side, which is facing the ejection charges. You don't want any gaps there:
012%207.jpg


Here it is all wrapped up:
013%207.jpg


I'm trying something new this time, I made a small pocket to hold the tubular nylon shock cord:
014%207.jpg


I'm gonna slide it over the end of the burrito to protect the (expensive) Skyangle chute from the ejection gas:
015%207.jpg


The Kevlar cord is fairly short, just enough to get the burrito out of the payload. As the nosecone pulls everything away, I should get a nice staged deployment.

With the pocket on the end, and a couple of shovels full of dog barf between the charge cups and the nomex, I should keep everything from getting damaged by what I figure will be a 5 gram ejection charge.
 
Wayne,
My L3 used a Skyangle 2XL chute which I wrapped up burrito syle similar to how you show in a 36" square nomex cloth. I too was worried about 6 grams of powder burning through the nomex, so I added a second nomex large octagonal protector near the charges. Worked like a charm... But I had a 8" tube to play with. I had so much room, I could have rented out some space :wink:
Looks good.

Adrian
 
It's been a while since I posted up on this thread, but I've been busy with other projects while some of the parts I need for this have been coming in. I ran out of 24 gauge speaker wire before I finished the sled for my avbay. When it came in I finished wiring the Schurter rotary switches in.
I also ordered some 5/16" eyebolts, a couple of them will go into Sharon's Gizmo XL, but I also replaced the 1/4" eyebolt on the bottom avbay lid for the drogue shock cord. I'm leaving the 1/4" eyebolt on the payload side, since there is no chance I will get any lateral pull with the shock cord coming down a 4 ft. payload tube. I agree with Dan's post though, it's not like the weight difference is a factor, and it makes me feel better with the larger eyebolt.
My next project is the nosecone. I'm mounting the Eggfinder flat on the top bulkplate of the N/C coupler. I made some plywood bulkplates and fit them together like an avbay lid, with the wider one on top and a thicker 3/4" plate with threaded inserts to hold it all in place. I used 6-32 flat head screws at the top of the coupler, recessed to clear the N/C:
008%206.jpg


I mounted the Eggfinder with nylon 4-40 screws and standoffs, which are screwed into t-nuts. The lipo battery has two sided tape and a zip tie holding it down, with plywood blocks glued to the bulkhead surrounding it.
006%206.jpg


I also built a stand for my transmit antenna, and attached it with a coaxial cable:
007%206.jpg


I like trying different mounting configurations for these Eggfinders, they are a fun soldering project, and I still haven't found out how high you can fly them before you lose signal. Put one up to 23,230 ft. and had good signal at apogee.
It's not likely I will lose this 12 ft. rocket, but the Eggfinder makes it easy to find regardless.
I epoxied in another fiberglass bulkplate at the other end of the coupler, recessed 1/2" so I could add a fillet. It has a 1/4" eyebolt with a fender washer and locknut for the anchor point.
Having most of the innards done, I started painting the fincan last week. When it took an entire rattlecan of primer to do the first coat, I realized I would go broke if I tried to paint it with the expensive cans I used on my "Red Tailed Extreme".

013-2.jpg


I really liked the Dupli-color Metalcast ruby red I used for that rocket though, so I went ahead and bought three cans at $9 each. I masked off the fins with three tapering lines going forward to the avbay, and masked off the switchband. After three coats of primer, and three coats of color, I brought it inside to weigh it. The only place on our house that I can stand it up on a hard surface is at the stairwell:
011%207.jpg


12 ft. 1.5" tall, it weighs 41 lbs.
I still need to add the "Darkstar" decal I got from Stickershock, and I will probably paint the metal nosecone tip to comply with Airfest rules, but other than some shear pin holes and vent holes, this rocket is ready.

 
Here's what it should look like when you get it just right:
039%203.jpg

How do you countersink your screws. I like to do the same thing but I ultimately get a misshaped hole due to the drill bit wandering. Can you also tell me which drill bits you are using?

Thanks and as usual the build looks great.
 
How do you countersink your screws. I like to do the same thing but I ultimately get a misshaped hole due to the drill bit wandering. Can you also tell me which drill bits you are using?

Thanks and as usual the build looks great.

I use this to countersink:
https://www.amazon.com/dp/B00004T7OQ/?tag=skimlinks_replacement-20

Not all of my holes come out perfect like the one pictured above, but with practice, a steady hand and the right tool, it is possible. I also use Dewalt drill bits and a compact bosch cordless drill.

https://www.amazon.com/dp/B004GIO0F8/?tag=skimlinks_replacement-20

https://www.amazon.com/dp/B00N8I29X2/?tag=skimlinks_replacement-20
 
Last edited by a moderator:
Keep in mind that not all flat head screws have the same angle under the head so sometimes you need an 82° conversion and sometimes you need a 90°'
 
^^^^yes, this. It took me some time to find a matching countersink to match the stainless screws I have. When it's done (right) it looks great and has zero drag.
 
I havent tried this.. would the doghouse tool help for this ?

Also would it be beneficial to sink the screw a hair and cover with putty CJ style ?

What size screw are you using on the UDS?

Kenny
 
I use this to countersink:
https://www.amazon.com/dp/B00004T7OQ/?tag=skimlinks_replacement-20

Not all of my holes come out perfect like the one pictured above, but with practice, a steady hand and the right tool, it is possible. I also use Dewalt drill bits and a compact bosch cordless drill.

https://www.amazon.com/dp/B004GIO0F8/?tag=skimlinks_replacement-20

https://www.amazon.com/dp/B00N8I29X2/?tag=skimlinks_replacement-20

I was using this type up to know, on a drill press. https://www.amazon.com/dp/B00B9J0V8W/?tag=skimlinks_replacement-20 However unless you can really secure the tube on the press it still wobbles slightly due to the fact that it is not symmetrical and puts force on the leading edge. The one you sent me the link for is symmetrical with 6 flutes, which will very likely resolve my challenge.

My holes are not too bad, see below, but none look as good as the one in your picture which looks perfect to my eye.

View attachment 268436

Keep in mind that not all flat head screws have the same angle under the head so sometimes you need an 82° conversion and sometimes you need a 90°'

I am going to look for the 90°' one as well, thanks.
 
Last edited by a moderator:
I havent tried this.. would the doghouse tool help for this ?

Also would it be beneficial to sink the screw a hair and cover with putty CJ style ?

What size screw are you using on the UDS?

Kenny

Are you talking about the drill guide tool? If so, that's not gonna work. You have the right idea though, most recessed holes look lopsided because the countersink is not held square to the hole.


I was using this type up to know, on a drill press. https://www.amazon.com/dp/B00B9J0V8W/?tag=skimlinks_replacement-20 However unless you can really secure the tube on the press it still wobbles slightly due to the fact that it is not symmetrical and puts force on the leading edge. The one you sent me the link for is symmetrical with 6 flutes, which will very likely resolve my challenge.

My holes are not too bad, see below, but none look as good as the one in your picture which looks perfect to my eye.

View attachment 268436



I am going to look for the 90°' one as well, thanks.

I suppose if it were gonna happen, it would happen here on TRF. I never expected to find someone as picky as myself, but here you are! Most of mine are much like the picture above. You need to drink a beer, it won't look bad at all if you do that.....
 
Last edited by a moderator:
I suppose if it were gonna happen, it would happen here on TRF. I never expected to find someone as picky as myself, but here you are! Most of mine are much like the picture above. You need to drink a beer, it won't look bad at all if you do that.....

:grin: guilty...but my vice of choice is red wine. However resistance is futile as I keep reverting back to my OCD nature.
 
Did some finishing touches to this build. Installed 1515 rail buttons, drilled 4-40 shear pin holes for the N/C and 1/4" vent holes in the fincan and payload tubes. I also epoxied in the t-nuts that I used to mount the eggfinder.
It's been incredibly hot here, I'm waiting for a break in the temp. so I can install the stickers and clear coat them. Also need to do ejection charge tests. That's about it for this rocket.
First flight will be an M2505 at Airfest.
 
Fantastic! My L3 build was nowhere near as detailed or nice as yours, but I did get it together for flying and should post it up soon.
 
Back
Top