My Level 3 build log - 7.5" Little John

[Theory]

as you are adding new fins and new centering rings, curious why you opted to start with a kit.

only asking as I have been bouncing around the idea of building a slobber knocker of an EZI-65 that would use slightly different fins and my own recovery system, and I keep coming back to buying parts and not the kit.

 

[conneryc]

as you are adding new fins and new centering rings, curious why you opted to start with a kit.

only asking as I have been bouncing around the idea of building a slobber knocker of an EZI-65 that would use slightly different fins and my own recovery system, and I keep coming back to buying parts and not the kit.

That's a good question. The reason is because when I added up purchasing all of the needed components individually, the price was higher than just buying the kit. So it was easier to just get the kit and then change out the components to match my design. I had actually wanted to do the LOC 7.5" IRIS for my L3, but LOC kept telling me "we MIGHT do a limited run again of the 7.5" IRIS this year, we will let you know". I got tired of waiting lol.

 

[conneryc]

Got everything cut out and ready to assemble the fin can. Looking forward to getting started.

 

[ljwilley]

Nice!

 

[conneryc]

Got the lower section mocked up, once I measure everything and make sure it's all square I'll mix up some West Systems epoxy and get to work. I'll
remove the lower centering rings and cover them with wax paper/saranwrap and re-install so that the epoxy won't stick to them. That way they will be removable and I'll be able add the internal fillets after everything is slid into the body tube before closing it up. Once the epoxy is cured I will ad Loctite to all of the nuts.

 

[conneryc]

More progress over the weekend. Got everything lined up and squared and secured it all together with a little 5 minute epoxy. Once that was cured I started with the fillets using West Systems epoxy with colloidal silica mixed in. After that, I measured and cut out pieces of fiberglass to securely bond the fins to the motor tube. Now its time to 'glass the body tubes.

 

[UPscaler]

What a rad L3 build! Best of luck!

Braden

 

[Hobie1dog]

 

[conneryc]

A little more progress this weekend. Got the fin can mocked up to verify fitment and cut out the forward bulkhead on the CNC. The fin can body tube was glassed using 10oz fiberglass sleeve from Soller Composites (https://sollercompositesllc.com/product/natural-uncolored-7in-light-fiberglass-sleeves/) and West Systems epoxy. Took 8 pumps of resin to fully wet out the cloth. Once that was done, it was wrapped with .003 Mylar and left to cure overnight.

 

[Tim51]

A little more progress this weekend. Got the fin can mocked up to verify fitment and cut out the forward bulkhead on the CNC. The fin can body tube was glassed using 10oz fiberglass sleeve from Soller Composites (https://sollercompositesllc.com/product/natural-uncolored-7in-light-fiberglass-sleeves/) and West Systems epoxy. Took 8 pumps of resin to fully wet out the cloth. Once that was done, it was wrapped with .003 Mylar and left to cure overnight.

View attachment 594966View attachment 594967View attachment 594968

Looking good. Are you leaving the all thread in place? (I would think that now everything's aligned and the epoxy is fully cured the fin can will be strong enough without it..?)

 

[Hobie1dog]

When you put a layer of fiberglass over cardboard and then add the resin thickness when you get done, at the end of the cardboard tube, isn't it going to be larger in diameter than your nose cone, which was the same OD as your cardboard tube when you started?

 

[conneryc]

Looking good. Are you leaving the all thread in place? (I would think that now everything's aligned and the epoxy is fully cured the fin can will be strong enough without it..?)

The all-thread will stay. I will help spread the loads from both thrust from one end and the shock of deployment at the other end. I'm not concerned about the additional weight. Considering that the first certification flight will probably be at the DARS Gunter, TX launch site that has a 3500' ceiling, the added weight will help it stay low. After that, the design will accommodate up to a 98/10240 case so subsequent launches may have to be at the TNT launch site in Seymour, TX

 

[Velocity Aerospace]

The all-thread will stay. I will help spread the loads from both thrust from one end and the shock of deployment at the other end. I'm not concerned about the additional weight. Considering that the first certification flight will probably be at the DARS Gunter, TX launch site that has a 3500' ceiling, the added weight will help it stay low. After that, the design will accommodate up to a 98/10240 case so subsequent launches may have to be at the TNT launch site in Seymour, TX

I'm a member of DARS too, pending a membership renewal. I look forward to hopefully being out there to see it. I saw Jack's "fluffy" fly, and thought it was wild. To see a level 3 rocket fly would be insane!

 

[conneryc]

Tip to Tip fiberglass layups and fillets completed. Let the sanding commence....

 

[Velocity Aerospace]

Tip to Tip fiberglass layups and fillets completed. Let the sanding commence....

View attachment 598082View attachment 598083View attachment 598084

Looking good

 

[ridnharley]

Any more of the build?

 

[conneryc]

Progress was delayed for a while as it was much too hot in my shop to work. I have re-started though and got another airframe tube glassed yesterday.

 

[ridnharley]

Progress was delayed for a while as it was much too hot in my shop to work. I have re-started though and got another airframe tube glassed yesterday.

Glad to hear it is coming along.
Looking forward to more coverage.

 

[bad_idea]

I'm a member of DARS too, pending a membership renewal. I look forward to hopefully being out there to see it. I saw Jack's "fluffy" fly, and thought it was wild. To see a level 3 rocket fly would be insane!

Fluffy had a stately flight. Was worried it might land in the tank and emerge a little less fluffy, but fortunately it didn't.

Will be great to see another L3 flight at Gunter.

 

[conneryc]

Little more progress. Airframe completed. All body tubes glassed and the electronics bay is being assembled. I was planning on using the 3D printed sled that I designed for my 4" IRIS so that I could easily swap them from rocket to rocket. Still working on the final design though. (Don't look at the messy shop lol)

 

[conneryc]

Working on the Electronics sled....

 

[conneryc]

E-bay complete. Just need to prime/paint the rest of the airframe, weigh it with all recovery hardware, determine the CG and update all of the parameters in RockSim. Then its on to ground testing and finishing my L3 certification package.

 

[kjhambrick]

Wow @conneryc !

I've never had an av-bay where I could almost fit my head inside

Nice !

-- kjh

 

[conneryc]

Construction is finally complete. All that remains is to install the arming switches, ground testing and finishing up the certification package....and then the flight. Airframe weight came to 40lbs, which includes 8lbs of weight in the nose. This will give just over a 2.0 balance margin with the M1500G that I will be using for the certification flight. The LOC RNWS will allow me to change that weight based on other motors I fly in the future. RockSim predicts a flight up to 5535'

 

[JackC]

My dad built a 6 inch version of the same rocket. Watch your flight critically to see if the rocket starts to cone. That will mean you need to add more nose weight to correct for that.

 

[Velocity Aerospace]

When are you planning on launching?

 

[conneryc]

When are you planning on launching?

Hopefully at the January or February launch at the DARS Gunter field. Only stipulation is that I would only be able to launch if the wind is out of the North. Otherwise there may not be room for recovery. In that case, I'd have to wait until the next TNT launch at Seymour

 

[Theory]

My dad built a 6 inch version of the same rocket. Watch your flight critically to see if the rocket starts to cone. That will mean you need to add more nose weight to correct for that.

“Coning” would indicate an over stable flight profile and one that would require the CG to move aft for correction. So less nose weight not more.

 

[Handeman]

“Coning” would indicate an over stable flight profile and one that would require the CG to move aft for correction. So less nose weight not more.

Looking at that rocket I'm kind of surprised it needs any nose weight at all.

 

[Velocity Aerospace]

“Coning” would indicate an over stable flight profile and one that would require the CG to move aft for correction. So less nose weight not more.

I never realized the cg being far forward could be an issue. What does coning look like?