L3 Build - Starless Rogue

[pathtouch]

With the announcement of LDRS coming to the Eastern US and looking for a winter project I decided to start on my L3 certification journey.

Initial criteria for me:

• Fiberglass airframe, as I occasionally launch on frozen lakes and they don't treat cardboard well.
• 98mm motor mount adapted to an AT M1315 in 75mm hardware for Cert flight.
• Apogee under 10,000ft to be east coast waiver friendly.
• Four fin design for added drag and better stability.
• Capable of flying on an L-impulse shake down flight

I decided I would like to create a loosely quartered scale model of the “Starless Rogue”. This is the proposed sub-orbital vehicle being developed by BluShift Aerospace. They are a Maine based company working on developing the first commercial rocket powered by carbon-neutral biofuel. After Pricing out options with several vendors the most economic source for airframe materials would be to start with an Ultimate Widman Kit from Wildman Rocketry. Tim Lehr was able to provide me with an additional fin, and slotted the airframe for a four-fin setup versus the standard three-fin offering. The overall length, nose cone profile, and fin shapes aren’t exact matches, but as the rocket hasn’t reached production yet I am satisfied with the look.




Naturally as soon as my box of goodies arrived I had to tape it all together and stack it up to get a sense of scale. I'll file this under large.



Aside from my extra fin, below is what you get with the Ultimate Wildman kit. The only exception is I cut myself an extra 1/8" G10 bulkhead for the nosecone. You'll see later on I used this to create a stepped bulkhead so I'll be able to maintain access to the nose cone for GPS trackers and other payloads.


I did the usual parts cleaning with warm soapy water to get rid of any stray dust/fibers and mold release.


All surface preparation for bonding fiberglass components will be based on advice from this forum and consist of sanding with 220 grit and cleaning with either acetone or denatured alcohol until a good water break surface is achieved. This 6" Bosch sander has been worth its weight in gold for prep on large diameter rockets and will continue to do so for this build. Hooking it up to a shop vacuum also greatly reduces the fiberglass dust let loose in the shop. My epoxy of choice is Total Boat 5:1 thickened with West 406 colloidal silica when needed. I've recently tested this product combo on a K2050 flight in a 4" bird @ 44Gs, and then proceeded to cut that fin can loose and drop it out of a 60 foot pine tree and not a single fillet was cracked.

 

[darrenf]

I've been kicking around the idea of doing level 3 at next year's LDRS, but I think that might be just a bit too much for me in the coming months. I really look forward to following your build and seeing it fly at Potter farms though.

 

[pathtouch]

Nose cone construction started by bonding the shoulder. I decided I wanted this epoxied in place. I have done Wildman kits where you leave this loose and rely on threaded rod and a larger bulkhead to hold everything together, but I feel like that can distort the nose cone shape.



Speaking of that bulkhead. I didn't think ahead to order, or ask for this to be swapped out to one that matches the OD of the shoulder. The stock kit comes with one matching the ID and the intent is for you to epoxy it in place. Luckily I had a sheet of 1/8" G10 and just cut my own extra bulkhead out, and bonded this to the stock bulkhead to create a super beefy stepped bulkhead. I attached a 1/4" u-bolt here with blue locktite, and drilled a hole to accept a long 1/4-20 rod from the aluminum tip.


Here you can see the 1/4-20 rod double nutted and locktited. This is essentially the nose cone ready for paint! I'll drill shear pins last after running some calcs.

The weakest component here hardware wise is the 1/4-20 rod, and that's rated to 1,900 lb ultimate strength. This nose cone is about 5lb, so unless a 380G deployment event happens nothing should fail.

 

[bad_idea]

So, uh, I guess the first chute that comes out will be the Starless Drogue?

(I'll show myself out.)

 

[pathtouch]

Steady progress in the rocket lab. Moving onto the motor mount. I squared up the tubes on a flat piece of tile with some 120 grit sand paper. I also did this for all the body tubes but didn't get a photo of that.



Next I predrilled the centering rings for the Aeropack and my two 1/4" u-bolts for recovery gear. Each u-bolt is rated for 2,822 so the two of them can handle over 5,600 lbs.


I tacked the centering rings in place with thick CA using the fins as spacers. Make sure u-bolts and fins don't conflict!


Using a 1/4" luan template, I tacked the fins in place with 5 minute epoxy. I like this approach as its easy to square things up and you can use the airframe to ensure fins are straight as well. Over an 18" long fin, if there is only a 1/32" of slop in the air frame you can't be more than 0.1 degrees mis-aligned axially. Also get that first fin centered between Aeropack mounting holes or you'll have a conflict with hardware.


Slid it all back out through slits in in the air frame behind the fin slots and prepped it for internal fillets.


Weapons of choice here. The popsicle stick mixer is key. Each pair of fins needs about a full pump which is around 25 grams of resin. Noting quantities for my future self when I'm doing the next big rocket.


Taped things off because I'm not a savage. Also note I taped over the Aeropack mounting holes so they weren't filled in accidently.


What's nice about the thickened epoxy is that you can do more than one fillet at a time. Note I epoxied backing nuts for u-bolts in place so they are now permanent.


I've got to get my recovery harnesses sorted out. I'm thinking of splicing some 3/8" kelvar directly to each u-bolt, creating a y-harness to the to top of the airframe, and then transitioning to 7/16" One-Bad Hawk harnesses from there. Or I may just use loops like I do on smaller rockets. Those are easier to replace and way more redundant.

 

[bunkermonkey9]

Loving this build thread

 

[Tim51]

Loving this build thread

+1

 

[rocketgeek101]

Great build so far! Very clean work.

 

[pathtouch]

Great build so far! Very clean work.

Thanks! I followed your Cosmic Kiss thread and YouTube vids intently. Btw I just flew with Mark R. the other weekend down in Maine, pretty sure he’s up your way quite often.

 

[rocketgeek101]

Thanks! I followed your Cosmic Kiss thread and YouTube vids intently. Btw I just flew with Mark R. the other weekend down in Maine, pretty sure he’s up your way quite often.

Yup, Mark and I live about 10 mins from each other. Was just out launching some models with him this past Thursday. We're currently planning a 2-stage M to L (or maybe even M to M ) project to build together for the next Rage at the Gage. Also hoping to finally make it down to Cherryfield sometime next year and meet some of you guys!

 

[pathtouch]

Made a decision on my Y-harness. I had a 3/8" One Bad Hawk harness from another rocket and I had to cut both sections of it out of a tree. I end-to-end spliced it like you would sailing dyneema (burying at least 47 rope diameters each side!). This shortened the cord about 5 feet so it was perfect length for a y-harness. Looks like Kip Daugirdas did some testing in this thread and thinks less may be necessary but I don't have a good pull test rig and am used to sailing rigging.... so more is better.
https://www.rocketryforum.com/threads/finger-trap-technique.137003/post-2504431


I rigged the harness like a semi equalizing but redundant rock climbing anchor. One strand is rated for 3,600 lb breaking, so using four strands shown below would be 14,400 lbs x 90% for the splice = 12,960 lb breaking. I've seen some dire numbers from Marlow Ropes that knotting aramid (kevlar) fibers can reduce strength to 30%! However if I didn't knot below the quicklink, a failure in any one strand would let the y-harness completely unravel. so I'll take the hit, especially at such high factors of safety. 30% of 12,960lb is still 3,888 lb, and that would mean a 15 lb fin can has to experience a 260 G deployment event, which will probably fail a lot of other components first. So any one of the four strands could get severed and I'd still maintain half the capacity.





Also made progress on the AV Bay. I masking taped the two bulkheads together back to back and drilled all the mounting holes out so they'll be symmetrical.


Then I tapped some holes for the charge wells.


For this rocket I'm going to have the U-bolt for the drogue side attached directly to the two all thread going through the AV bay. This way the highest deployment forces aren't transferred into the rear bulkhead. Yes they'll in theory be applied to the front bulkhead, but that will be a force pulling it against the AV bay coupler, much more evenly distributed around the circumference, and shared with the hardware holding the payload section to the AV bay.



Also got the switch band epoxied into the center of the coupler.
This electronics sled is shared between all my rockets 4" diameter or larger. I just have to make the threaded rod spacing similar between rockets and it slides right in. Big cost savings! I may finally upgrade it to a G10 sled, but that cheap plywood has survived a K2050 at 42Gs. I wonder if the less rigid material helps lower impact on the components?


Decent backing plates and fender washers at all u-bolts too.


Charge wells are Schedule 40 PVC 3/4" pressure caps. This is what 5grams of powder looks like in them. When I ground test next week we'll see if they survive....


Also got a smoking good deal on my main chute so the only thing left to purchase is my recovery harnesses. Waiting to see what blackfriday deals come along for that!

 

[OzHybrid]

Nice rocket. But it's not a 1/4 scale of the BluShift if the fins are a different size, different angles too and the nosecone is completely different. I'll concede they both have 4 fins...... That's not a loose scale, it's rattling.

 

[pathtouch]

Nice rocket. But it's not a 1/4 scale of the BluShift if the fins are a different size, different angles too and the nosecone is completely different. I'll concede they both have 4 fins...... That's not a loose scale, it's rattling.

Hey at least I’ll paint it the same colors

In other news no major progress this past week, had to get a bunch of things around the house ready for winter. Hopefully I’ll have time to tinker on this after thanksgiving!

 

[OzHybrid]

Hey at least I’ll paint it the same colors

In other news no major progress this past week, had to get a bunch of things around the house ready for winter. Hopefully I’ll have time to tinker on this after thanksgiving!

The stretched graphic on the nosecone is going to be unreadable. Best of luck with your cert.

 

[pathtouch]

Maybe I'll make the decals say "Scaleless Rogue"!

I finally got around to playing in the shop this weekend. I cut a block to size and shaped it on the bench sander to use as a backing block and got all my vent holes and static ports drilled out. I usually center punch, pilot hole, then full size bit, all with a backing block and tear out is minimal.



I also drilled a hole in the nose cone bulkhead to vent that to the interior of the payload bay. As far as static port sizes I used the usual guidance of a 1/4" diameter per 100 cubic inches of interior volume. My AV bay is 6"x16"=452 cubic inches and required (3) 0.307" holes so I rounded up to 5/16 (0.3.125") and drilled three of those spaced equally around the switch band.
I used the same 5/16" diameter to make a vent hole in the fin can at the calculated center of pressure. I like locating it there on my rockets so I always have a reference for COP without using a sticker or marker.
I made another vent in the payload bay an arbitrary distance from the nose cone.


Then it was time to prepare and epoxy the fin can into the airframe. Before I slid this all the way in I epoxied in a weld nut for the aft rail guide. Notice how I taped all the kevlar harness up. This not only protects it from epoxy, but also any future ejection charges. Getting epoxy on the harness will concentrate forces and could be reduce overall strength.


Got the fine can all the way in, tourniqueted the back of the airframe to clamp it around the aft centering ring, and epoxied the forward rail guide in with another weld nut.


Also sometimes you have to tape a popsicle stick to a piece of scrap to get that top centering ring fillet into ship shape.


While that cured I got around to epoxying some #6-32 hardware into the AV bay to secure the Payload tube to it. This is just so much easier to source parts for and cheaper than PEM nuts it's my go to method still. I just slather Super Lube in the threads to keep the epoxy out and epoxy a nut to the interior.


So I'm down to external fillets, shear pins, and mounting a camera shroud then it's time for paint.

 

[roytyson]

Did this method crack the fiberglass? Havent seen many people do this method with glass.

 

[DAllen]

 

[pathtouch]

Did this method crack the fiberglass? Havent seen many people do this method with glass.
View attachment 617296

No cracks but the hacksaw blade pulled a fiber out of the interior in a few spots. Maybe next time I’ll dremel it. No concerns since this all gets reinforced by centering rings and fillets.
Here’s what it looks like from the outside.

 

[Rschub]

Having done this twice on cardboard, that actually looks much neater.

 

[frogglicker]

 

[pathtouch]

Started external fillets today. Total Boat Epoxy and West 406 Colloidal Silica per usual. Decided to follow the typical guidance of fillet radius = 4% fin root chord length. With an 18” chord this comes to about 3/4”. Found a socket in the toolbox with an 1.5” OD and went to town. Did the usual sanding and acetone prep.

 

[pathtouch]

Been a while, I was going to try and get this together for a December launch but holiday and weekend plans with the family took over most of my free time. To catch up, I got the Aeropack all mounted up.




I got around to soldering up an Eggtimer Proton so I can finally retire my Adept 22 and capture accelerometer data. Got it mounted to my AV bay sled too.





Then the kiddo helped supervise packing all the recovery gear. A Skyangle Cert 3 XL, Recon 24” drogue, and typical 7/16” One Bad Hawk harnesses will make up that portion.



My goal now is to make it to the next CRMRC launch in January and fly this on a K1050 to about 3k feet for a good shake down run then get it painted. I had to make a 54-98mm adapter out of some 1/2” birch ply for that particular motor.



Today I finalized ground testing too. I’m going with four 4-40 shear pins which can restrain the nose cone under a 50g event (drogue coming out with a lot of horizontal velocity). I’ve heard of Ultimate Wildman flying in N motors with no shear pins on the back end. I’m gonna just go with the same shear pin setup there to help me sleep at night. 5g of Triple 7 FFFg was fine for the main but I needed 6g in the drogue. That sure is a lot of powder for me but honestly I think 3 grams in my 7.5” Doorknob was louder haha. Also the PVC charge wells held up fine. I was half expecting to find them shattered.



I made a YouTube short of you wanna see what ground testing was like.



Gotta get that camera shroud mounted and then comes the dreaded painting and sanding.

 

[OzHybrid]

see next

 

[OzHybrid]

You should be using black powder for ejection, not smokeless powder as you stated in your test. 2 completely different beasts.... Smokeless requires more containment for combbustion.... At that point it goes kaboom. NOT recommended. You want BP. for a woosh. Not a kaboom. It's the lowish pressure over a largish area that breaks the pins. You don't want a shockwave....
While on paper smokeless has better performance, thats not true for its use uncontained, as we use it in ejection charges. Uncontained, black powder burns faster which means you can use less of it. Which is safer ..
This is the opposite of the performance of the 2 in a bullet, where there is substantial containment.

 

[pathtouch]

You should be using black powder for ejection, not smokeless powder as you stated in your test. 2 completely different beasts.... Smokeless requires more containment for combbustion.... At that point it goes kaboom. NOT recommended. You want BP. for a woosh. Not a kaboom. It's the lowish pressure over a largish area that breaks the pins. You don't want a shockwave....
While on paper smokeless has better performance, thats not true for its use uncontained, as we use it in ejection charges. Uncontained, black powder burns faster which means you can use less of it. Which is safer ..
This is the opposite of the performance of the 2 in a bullet, where there is substantial containment.

Thanks for the concern and great points. Maybe calling Triple 7 smokeless powder is a bit misleading as Hodgdon calls it a black powder substitute. Either way I wanted to make it clear this wasn’t black powder.

Since there’s a shortage in Black Powder I’ve used 777 these past two years. I also know of some other well known members here that use it successfully. Use charge wells and put your e-match on top, so the flame front travels downward toward containment and it’s less likely to throw unburnt powder outward. Cover that with dog barf and tape. The key is definitely containment, I make four X’s out of masking tape strips (8 layers), and after each X go around the perimeter with a layer of masking tape.
It still has some slower burning embers so make sure your chutes are packed really well in nomex.

I’ve heard it’s much less corrosive and easier to clean up so while not advocating for it to replace BP I’ve had a great experience with it.

 

[r1dermon]

Thanks for the concern and great points. Maybe calling Triple 7 smokeless powder is a bit misleading as Hodgdon calls it a black powder substitute. Either way I wanted to make it clear this wasn’t black powder.

Since there’s a shortage in Black Powder I’ve used 777 these past two years. I also know of some other well known members here that use it successfully. Use charge wells and put your e-match on top, so the flame front travels downward toward containment and it’s less likely to throw unburnt powder outward. Cover that with dog barf and tape. The key is definitely containment, I make four X’s out of masking tape strips (8 layers), and after each X go around the perimeter with a layer of masking tape.
It still has some slower burning embers so make sure your chutes are packed really well in nomex.

I’ve heard it’s much less corrosive and easier to clean up so while not advocating for it to replace BP I’ve had a great experience with it.

Not sure of your location, but as a NH resident, two places I have seen it recently are Kittery trading post in Kittery, ME, and trader johns in winchester, NH. both sell goex.

 

[pathtouch]

Not sure of your location, but as a NH resident, two places I have seen it recently are Kittery trading post in Kittery, ME, and trader johns in winchester, NH. both sell goex.

Hey Neighbor!

I’m actually like 40 minutes away from KTP and Maine Powder House so once this container of Triple 7 is kicked I might try out some Goex. Was at KTP this summer buying some cannon fuse for my…. cannon, and they were sold out if FFFFg at the time.

 

[r1dermon]

Hey Neighbor!

I’m actually like 40 minutes away from KTP and Maine Powder House so once this container of Triple 7 is kicked I might try out some Goex. Was at KTP this summer buying some cannon fuse for my…. cannon, and they were sold out if FFFFg at the time.

Are you in Maine or NH? I am a field engineer in new england and travel maine, NH and MA every day, so sometimes I like to pop into the various gun shops and trading post type places and see if they have any stock. Found leatherman ratchets a few weeks ago at LL bean in freeport which is like a unicorn. Anyway if I find some goex I'll shoot you a line.

 

[pathtouch]

Are you in Maine or NH? I am a field engineer in new england and travel maine, NH and MA every day, so sometimes I like to pop into the various gun shops and trading post type places and see if they have any stock. Found leatherman ratchets a few weeks ago at LL bean in freeport which is like a unicorn. Anyway if I find some goex I'll shoot you a line.

Im about 20minutes south of Portland Maine. Sure let me know if anyone’s got it in stock!
I’m trying to make it to the CRMRC launch in VT the 20th if you’re doing any launching this winter. I’ll be flying this in a big K to shake it down. Hopefully we get some good ice and can launch on lake Winnie too.

 

[r1dermon]

Im about 20minutes south of Portland Maine. Sure let me know if anyone’s got it in stock!
I’m trying to make it to the CRMRC launch in VT the 20th if you’re doing any launching this winter. I’ll be flying this in a big K to shake it down. Hopefully we get some good ice and can launch on lake Winnie too.

Just getting back into the hobby after a 10 year hiatus so whatever time I have just isn't enough haha. 20th I probably won't make unfortunately, and then we're away in Feb so my next launch is looking like March. Hopefully I can get a rocket built that would be suitable for an L2 attempt but we'll see what I can get my hands on.

I am in Scarborough all the time, today I was in south Portland and tomorrow I'll be in Norway Maine. I'll be sure to pop into ktp on my way home and see what they have for stock.