"Starship" - L3 Build Thread

[Ben Martin]

This is the build thread of my Performer 98 named "Starship". I plan on using it to gain L2 experience then go for my L3 when the time is right. Expected completion time is around a month, you can expect frequent updates through this thread.

Build materials:

Kit: Performer 98

Epoxy: Rocketpoxy and JB Weld

Tailcone: Aeropack 75P/3.9"

Ubolts: 3x #385 in total, 2 for electronics bay and 1 for nosecone.

Quicklinks: 5x 5/16 Zinc

Recovery:

Electronics: Dual Stratologger CFs with Additive Aerospace 3D printed sled and surface mounted screw switches.

Charge wells: 2x Dog House Rocketry Ejection Charge Mount kit (terminals + charge well combo)

Shock cord: 2,520lb Rocketman kevlar, 2x motor tube mounted and 2x 3 loop

Parachutes: Rocketman 6ft and 2ft (not final)

If you guys have any questions, comments, or concerns please feel free to post them on this forum or message me. Excellent advice and feedback is what I love about this forum.

 

[Ben Martin]

Update #1:

Picture 1: Notched the forward centering ring with a rotary tool for the shock cord motor mount.

Picture 2: Test fit the notched forward centering ring with the shock cord.

Picture 3: Epoxied the switch band to the coupler with RocketPoxy. It was my first time using RocketPoxy and I'm liking it thus far.

Picture 4: Epoxied the forward centering ring to the motor tube with the shock cords in place. Smoothed/shaped fillet with isopropyl alcohol.

Picture 5: Secured shock cord mount to the motor tube. I will be putting an epoxy fillet on the other side of the centering ring tomorrow.

Picture 6: Epoxied nosecone coupler into the nosecone.

Tomorrow I plan on completing the forward centering ring fillets, test fitting the motor retainer (marking locations of all the centering rings) and marking holes for ubolts/charge wells.

 

[Bat-mite]

A quick word. Get some stainless quick-links and hardware. The zinc-plated stuff oxidies rapidly, and they need to be replaced every few flights in my experience.

 

[Theory]

X2 on the stainless hardware!

also, let me state that I fully support this statement

"I plan on using it to gain L2 experience then go for my L3 when the time is right."

There is a lot to learn at L2, and a lot of "meat" in the J, K and L impulse range. looks like you are off to a great start. take your time and things will come out as expected.

 

[Ben Martin]

A quick word. Get some stainless quick-links and hardware. The zinc-plated stuff oxidies rapidly, and they need to be replaced every few flights in my experience.

That was actually going to be one of my questions. I'm going to switch to 1/4in stainless ubolts and stainless quicklinks. Even though I have not experienced zinc-platted oxidizing yet, the added resistance and strength of stainless steel is worth the few extra dollars.

 

[Bat-mite]

Agreed. And every time I have to use pliers to open an oxidized quick-link, I have to chide myself for trying to save a few bucks by wasting so much time and energy.

 

[Ben Martin]

X2 on the stainless hardware!

also, let me state that I fully support this statement

"I plan on using it to gain L2 experience then go for my L3 when the time is right."

There is a lot to learn at L2, and a lot of "meat" in the J, K and L impulse range. looks like you are off to a great start. take your time and things will come out as expected.

I am certainly switching to stainless, it's worth the extra cost. The plan is to have a lot of fun with L2 and learn everything that I need for a successful L3 certification. This rocket is being build with the L3 requirements in mind so that I can use it as such in the future.

 

[Scottrod]

A quick word. Get some stainless quick-links and hardware. The zinc-plated stuff oxidies rapidly, and they need to be replaced every few flights in my experience.

of course you say this after I bought a three pack of zinc quick links yesterday.

 

[Ben Martin]

of course you say this after I bought a three pack of zinc quick links yesterday.

I feel the same way, I just bought all the ubolts and quicklinks a few days ago. Stainless costs a considerable amount more but it should be worth it.

 

[Bat-mite]

of course you say this after I bought a three pack of zinc quick links yesterday.

You can use them, but they do get nasty. They probably last a little longer if you hose them down with WD-40 after each flight.

 

[jmwoody]

Great start Ben! I along with others will be watching your build.

Where the Kevlar harness rides against the fiberglass motor tube round off the edges of the fiberglass ... it cuts and abrades like a knife.

+1 on SS hardware and Rocketpoxy and JB standard strength epoxy. It's not how many rockets one owns ... it's the quality of the rockets one owns and your well on your way to owning a great rocket.

 

[Ben Martin]

Ordered 316 1/4" stainless steel quick links off Amazon. They are more resistant to corrosion than the 304 stainless steel quick links that people typically use in rocketry. $13 for 4 quick links is a great deal.
https://www.amazon.com/gp/product/B01KYPOYKC/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[Tobor]

You can use them, but they do get nasty. They probably last a little longer if you hose them down with WD-40 after each flight.

Although WD-40 will work, I would recommend dielectric grease. It is silicone based but can withstand high temperatures and is non-conductive.

IIRC WD-40 can actually attract moisture when it begins to break down. But, don't quote me on this.

 

[Nytrunner]

Wasting no time!

Good choice for a simple performance L3. Stick a payload in there and you've got an IREC/Spaceport cup commercial 10k entry!

 

[Ben Martin]

Update #2:

Attempted to dry fit the motor retainer on but I found out that the OD of the motor mount tube is considerably larger than the ID of the retainer. I know that I purchase the correct one so I assume it was just a manufacturing tolerance issue with the fiberglass motor mount tube. I attempted to sand the motor tube down and after a pretty substantial amount of sanding the motor retainer still does not fit.

I guess that the best idea is to just keep sanding until it actually fits? There's nothing else I can really do but I don't want to weaken the fiberglass tube.

 

[GalantVR41062]

Use a caliper to measure the ID of the tailcone retainer body vs the OD of the MMT.

If I had to modify the parts to work I would use a lathe to machine the tailcone retainer body to fit the fiberglass mmt.

What motors are you looking at for test flights and the L2 attempt?
What type of tracking are you going to be using?
What simulation software are you using?
I recommend your decent rate for the certification flight to be 15'/s under the main.
Are you going to have any swivels in the recovery gear? I like having one on the drouge section to booster, and my chutes.
Nomex pads (12" square min) for the drouge and main section, any plans for a laundry shelf?
Are you going to be using shear pins for the nose cone, eBay, and rivets or screws for the payload bay?

Ground test, be proficient at the prep on your rocket, study for the L2 test, pics and video along the way, learn, and good luck.

~John

 

[Ben Martin]

Use a caliper to measure the ID of the tailcone retainer body vs the OD of the MMT.

If I had to modify the parts to work I would use a lathe to machine the tailcone retainer body to fit the fiberglass mmt.

What motors are you looking at for test flights and the L2 attempt?
What type of tracking are you going to be using?
What simulation software are you using?
I recommend your decent rate for the certification flight to be 15'/s under the main.
Are you going to have any swivels in the recovery gear? I like having one on the drouge section to booster, and my chutes.
Nomex pads (12" square min) for the drouge and main section, any plans for a laundry shelf?
Are you going to be using shear pins for the nose cone, eBay, and rivets or screws for the payload bay?

Ground test, be proficient at the prep on your rocket, study for the L2 test, pics and video along the way, learn, and good luck.

~John

I'll measure it with a caliper tomorrow. I can tell that it is very close to fitting now but it took quite a bit of sanding. I imagine that the JB Weld and metal ring will strengthen the sanded section of the tube.

I am using OpenRocket to simulate my rocket. I have already made an initial simulation of the rocket that I will be updating throughout the build process. For tracking I plan on using the T3. For parachutes I plan on getting one size larger than I need, meaning that it will be 15fps or lower on main. For test motors I plan on initially putting it up on a large "J" then progressing to "K" and "L" and when the time is right I will put a baby "M" in it for my L3.

I am going to be using swivels on each parachute and possibly one attached to the booster harness. I have 18 x 18" parachute protectors for the main and drogue. I plan on using shear pins for the nosecone to hold the main in and screws for securing the payload bay. Ground tests will be conducted before it flies and I already have my L2. I am certainly going to document it the whole way, from this build thread to onboard cameras.

Thanks for the advice!

 

[Steve Shannon]

You shouldn’t worry about thinning the g12 motor mount tube too much unless they sent you the 75L body by mistake. 75P bodies have slipped onto the g12 tubes I’ve gotten from Wildman without any sanding other than normal prep for epoxy.
Even if they sent you a 75L body I doubt that the tube would fail. G12 tubing can withstand a lot of thrust and there’s relatively little tension.

 

[ECayemberg]

Dremel tool + 60 grit sanding drum= quick work of turning down the OD for your retainer.

There are other ways, but the above is simplest and quickest IMO. A sanding sponge as pictured above is probably the worst tool for the job as you want a solid surface to sand against your tube (IE: sanding block). A sponge will tend to round off the edges without taking a lot off the OD of the tube.

Take down the OD however possible, glue it on with JB Weld, and fughetaboutit!

 

[Ben Martin]

Update #3

Sanded down the motor tube for the motor retainer to fit. It took a tremendous amount of dremeling to make it fit, not a normal installation experience.

Picture #1: Added the rear epoxy fillet on the forward centering ring. Epoxied 2nd centering ring onto the motor tube. I will be installing the motor tube without the rear centering ring and motor retainer attached as I'm going to attempt to use wooden dowels to do internal fillets.

Picture #2: Planned out ubolt and threaded rod positions. I figured that I should use stainless steel ubolts instead of forged eyebolts as they have a large surface area. Forged eyebolts would be much easier however, as there's already a hole drilled and it would take up less space. Decisions... decisions... either one will work perfectly though so in reality it doesn't matter too much.

 

[jqavins]

This is the build thread of my Performer 98 named "Starship". I plan on using it to gain L2 experience then go for my L3 when the time is right.

Doesn't an L3 build require lots of documentation and an adviser (I forget the official term) to monitor the build? Did I skim too fast and not see that you're doing that? Point is, if you do this very nice build of this very nice L2 rocket and get lots of flying experience, which is all a very good thing, mightn't you have to start over with another one for an L3 attempt?

 

[C.O.B.H.C.]

I wouldn't run the U-bolt in line with the all thread rods as you're making the bulkhead weaker in that one direction. I hope that makes sense. Run the U-bolt in the opposite direction of the threaded rod to spread the load out more evenly.

 

[Ben Martin]

Doesn't an L3 build require lots of documentation and an adviser (I forget the official term) to monitor the build? Did I skim too fast and not see that you're doing that? Point is, if you do this very nice build of this very nice L2 rocket and get lots of flying experience, which is all a very good thing, mightn't you have to start over with another one for an L3 attempt?

Tripoli allows you to use a rocket that you have already build for your L3 if you have proper documentation. That is exactly what I am doing during this build, documenting it so that after a few flights I can use it for an L3 attempt.

 

[Ben Martin]

I wouldn't run the U-bolt in line with the all thread rods as you're making the bulkhead weaker in that one direction. I hope that makes sense. Run the U-bolt in the opposite direction of the threaded rod to spread the load out more evenly.

I did that to allow more room for the ejection charge mounts but I'll check to see if it will fit the other way.

 

[gwh]

Clicked on this thread expecting a scale build of SpaceX's Starship... cool build nonetheless! Keep up the good work.

 

[Ben Martin]

Clicked on this thread expecting a scale build of SpaceX's Starship... cool build nonetheless! Keep up the good work.

That would be amazing, sounds like I know what my next project is going to be. Sorry to disappoint but thanks for the support!

 

[Nytrunner]

Wouldn't be the hardest, the starship is basically a fat Jart with monokote over it

 

[Ben Martin]

Update #4

Picture #1: Secured loose cord with epoxy.

Picture #2: Checked centering ring alignment before prepping body tube and motor tube for epoxy.

Picture #3: Patent pending popsicle stick taped to an aluminum angle. I used it to distribute the rocketpoxy inside of the body tube. It worked surprisingly well.

Picture #4: Motor tube epoxied to the airframe. Only the front two centering rings were epoxied with the rear centering ring and retainer held in place for alignment and spacing. It appears that I used a lot more epoxy that I actually did. All of the spreading is from putting the circles of epoxy for the CR at the same time, causing the front centering ring to push the epoxy up with it.

This will likely be the last update until after spring break. I will be receiving a bunch of parts (electronics, recovery) over the break so that I will be ready to rock and roll once I get back.

 

[Bat-mite]

Right on the dining room table, huh?

 

[Ben Martin]

Right on the dining room table, huh?

End of the hall of my residence hall. People like seeing a rocket being built.