My first minimum diameter build

[ac2fv]

I just purchased a Laserloc 1.6 kit, it will be my first md build. I should mention that I have built many hpr rockets. My question is, as a first md attempt, should I build the kit as is, or build in electronic ejection, etc?

My gut is telling me build the kit as is…

Thanks in advance

 

[Hobie1dog]

have you built HPR with electronics for deployment?

 

[ac2fv]

have you built HPR with electronics for deployment?

Yes. But nothing this small. It will be my first attempt at using fiberglass on fins too

 

[Hobie1dog]

What motor are you going to use? How high is the predicted altitude?

 

[Pepe Le Pew]

Build it as a kit, you have already built many HPR, DD.

 

[watheyak]

The issue with a lot of minimum diameter rockets is that the flight times exceed the delay of most motors, so electronics deployment is your only option.

 

[Conway Stevens]

The issue with a lot of minimum diameter rockets is that the flight times exceed the delay of most motors, so electronics deployment is your only option.

Exactly this. Electronic dual deployment is a must. As is high quality Tracking. Minimum diameter flights usually take very little to go high and out of sight. Motor ejection is useless for these flights. As is visually tracking them.

Motor choice really does make a difference in how it should be built structurally.

 

[ac2fv]

Thanks to all for your wisdom. I will smash ahead with electronics. My first flights will be fairly low altitude, as we have a 4500’ ceiling. My eyes are looking forward to next year at LDRS, where I can fly higher.

 

[Hobie1dog]

what model altimeters do you use?

 

[ac2fv]

what model altimeters do you use?

Funny you should ask, that was my next question. I have a Featherweight GPS tracker, which may or may not be the tracker to use in this situation. Any recommendations?

 

[Hobie1dog]

Funny you should ask, that was my next question. I have a Featherweight GPS tracker, which may or may not be the tracker to use in this situation. Any recommendations?

I was just thinking of the small physical sizes that are available now.

 

[ac2fv]

I was just thinking of the small physical sizes that are available now.

It's something I really need to research. My Featherweight is small, but the antenna is big. My goal is to get the rocket built over the winter, fly it at low altitudes (2-3K) next year April-May, and then go for broke at LDRS

 

[Conway Stevens]

Funny you should ask, that was my next question. I have a Featherweight GPS tracker, which may or may not be the tracker to use in this situation. Any recommendations?

For my minimum diameter builds 38mm and up i use Raven4 and Blue Raven altimeters and the featherweight tracker.

 

[ac2fv]

For my minimum diameter builds 38mm and up i use Raven4 and Blue Raven altimeters and the featherweight tracker.

Thanks, Conway! This will be a new challenge for me, but that's what I like about it! Do you put the tracker in the nosecone? Pics would help...

 

[watheyak]

I put them both as far forward as they will go in the nosecone. That ares is usually just empty space.

 

[ac2fv]

I put them both as far forward as they will go in the nosecone. That ares is usually just empty space.
View attachment 595087View attachment 595089

Thanks. Man, do I have a lot to learn! That sled has everything but the kitchen sink in a very small space! Are the knurled nobs the connection points for ejection charges?

 

[kjhambrick]

I put them both as far forward as they will go in the nosecone. That ares is usually just empty space.

That is beautiful, @watheyak !

One Q: How do you get ambient air pressure in there for the Featherweight *Raven ?

-- kjh

 

[watheyak]

That is beautiful, @watheyak !

One Q: How do you get ambient air pressure in there for the Featherweight *Raven ?

-- kjh

Thanks! There's a static port way up front. Even though it points into the relative wind a bit due to the nosecone curvature, the Raven handles it just fine. It makes for some inaccurate data from the baro during boost, but by the time it's at apogee the airspeed is slow enough that it doesn't affect deployment.

 

[b.wieting]

While I'd always favored fat rockets, this year I built a Wildman Blackhawk 38, dual deploy.
Space constraints definitely made building the e-bay trickier. I used an EF Quantum (wifi control eliminates need for an external switch. Doghouse charge wells were great, just fit in the available space.

I also strongly endorse a GPS (I use an Eggfinder).

Have had 3 good lower impulse flights, have the drogue streamer + main all sorted out.
Planning a max flight (J500G) for this fall once the desert cools off...

 

[Conway Stevens]

Thanks, Conway! This will be a new challenge for me, but that's what I like about it! Do you put the tracker in the nosecone? Pics would help...

This is the sled in my last project. Tracker on one side. Altimeter, Altimeter battery, tracker battery on the other side usung the perch. All fits inside the avbay for a head end deployment set up. The main chute is in the nose. Drogue above the motor. Used all 4 channels for deployment. I have done similar set ups like Scott aka Watheyak with cable cutters. And a single break with electronics in the nose. Last project was a 54mm min diameter that went 31,374 on a K. Not enough for the record. But fun flight.
If you want to see impressive you should check out Scotts flight on the Loki L

 

[kjhambrick]

Very nice Conway !

What material is the threaded rod along spine of your sled ?

Thanks !

-- kjh

 

[mtnmanak]

38mm is not much room, but it is more than you think. I made a 29mm MD rocket and I was able to fit a MW RRC2L in the ebay with a 29mm sled MW makes. It was a very tight fit and required a bit of modding to get it in there, but I have flown it many times with no issues and the dual deployment works every time. I always thought 38mm MD was small, but after the 29mm build, 38mm seemed spacious

https://www.rocketryforum.com/threads/29mm-minimum-diameter-dual-deploy-go-devil.165916/

 

[ac2fv]

38mm is not much room, but it is more than you think. I made a 29mm MD rocket and I was able to fit a MW RRC2L in the ebay with a 29mm sled MW makes. It was a very tight fit and required a bit of modding to get it in there, but I have flown it many times with no issues and the dual deployment works every time. I always thought 38mm MD was small, but after the 29mm build, 38mm seemed spacious

https://www.rocketryforum.com/threads/29mm-minimum-diameter-dual-deploy-go-devil.165916/

Great build! I, too, have a lot to learn, but for me that's the fun of it. I may ping you down the road with questions...

 

[mtnmanak]

Great build! I, too, have a lot to learn, but for me that's the fun of it. I may ping you down the road with questions...

Feel free to ping me anytime. Also check out @rfjustin 's post on building an MD WM Mach 3:
https://www.rocketryforum.com/threads/wildman-mach-3.158888/

 

[b.wieting]

Great build! I, too, have a lot to learn, but for me that's the fun of it. I may ping you down the road with questions...

One more suggestion--it saved me space eliminating quicklinks at e-bay eyebolts: "finger trap", taught in a post by Lowpuller.

Finger Trap Technique​

 

[kjhambrick]

@mtnmanak --

Thanks for the link to your web pages: Mountain Man Rockets

Very Nice !

You've got a lot to study and learn from over there !

-- kjh

 

[kjhambrick]

One more suggestion--it saved me space eliminating quicklinks at e-bay eyebolts: "finger trap", taught in a post by Lowpuller.

Finger Trap Technique​

Yes !

THANKS @b.wieting !

I am installing a 0.0625 inch / 1.6 mm - 750 lbf braided Kevlar shock cord in my latest BT-55 model Vulcanite, La Pequeña Vulcanita, and the finger trap worked for even that small diameter braided Kevlar !

I did taper the tail and I buried ( 21 * 3.5 * 0.0625 ) = 4.5 inches ( from @manixFan's Video Link ).

It seems strong without any stitches and yet I can still push it together to release the tail.

No quicklinks in that little girl !

I made a fid from the bare copper wire from an old Davey Fire e-match to pull the tail.

Thanks for the link ( and also see @caveduck's and @manixFan's links on that same thread !

Nice !

-- kjh

 

[Conway Stevens]

Very nice Conway !

What material is the threaded rod along spine of your sled ?

Thanks !

-- kjh

Its a grade 5 #8-32 all thread. I used the Addative Aerospace harness anchors with it.

 

[Conway Stevens]

Yes !

THANKS @b.wieting !

I am installing a 0.0625 inch / 1.6 mm - 750 lbf braided Kevlar shock cord in my latest BT-55 model Vulcanite, La Pequeña Vulcanita, and the finger trap worked for even that small diameter braided Kevlar !

I did taper the tail and I buried ( 21 * 3.5 * 0.0625 ) = 4.5 inches ( from @manixFan's Video Link ).

It seems strong without any stitches and yet I can still push it together to release the tail.

No quicklinks in that little girl !

I made a fid from the bare copper wire from an old Davey Fire e-match to pull the tail.

Thanks for the link ( and also see @caveduck's and @manixFan's links on that same thread !

Nice !

-- kjh

I have sewn loops on my harness and with the anchor points and how i set things up i never use quick links. In fact i Never use any metal quick links ever. Doesnt matter if its a 38 or 54mm min diameter or if its an 8 inch diameter 100 lb rocket. If i cant attach the sewn loops directly i use a soft link.

 

[kjhambrick]

I have sewn loops on my harness and with the anchor points and how i set things up i never use quick links. In fact i Never use any metal quick links ever. Doesnt matter if its a 38 or 54mm min diameter or if its an 8 inch diameter 100 lb rocket. If i cant attach the sewn loops directly i use a soft link.

Thanks for the info Conway !

I forgot to mention ...

I thought I saw a video here on TRF where tapered tails were discussed.

I couldn't find it but I did find a good video on YouTube about tapering the tail before pulling it into the core:

The Rigger’s Craft—The Eye Splice

The tapered tail DEFINITELY reduced the effort required to start the pull for an eye splice on my 1/64 inch diameter braided Kevlar.

The craftsman, Kristian Martincic, also wrapped a whip with nylon thread below the eye to hold the Eye Splice at low loads.

I am going to try that too -- I like that he was able to melt the ends of the whip to clean it up.

Back to practicing eye splices on various diameter braided Kevlar

-- kjh