Terrier-Sandhawk

[hambirm2018]

I’m building a LOC Terrier-Sandhawk and doing an E-bay install from Apogee. Almost done!

 

[heada]

How are you doing motor retention on the 38mm Sandhawk?

 

[hambirm2018]

I’m going to try and get a 38mm retainer epoxied on but Tape if all else fail. I still have not decided on a reload or a one time use but that will also go into factor.

 

[heada]

I have the same kit and was going to use a Giant Leep Slimline threaded retainer. I don't like just tape for HPR and an aeropack is too wide.

 

[Cameron Anderson]

I have the same kit and was going to use a Giant Leep Slimline threaded retainer. I don't like just tape for HPR and an aeropack is too wide.

Smart move on the slimline.
I got my Aeropack for my Sandhawk in there but I had to send the inside of the Terrier ISC and I had to dremel a channel for the sustainer ignitor to fit past the retainer. It worked alright but if I redo this build I would go slimline.

 

[hambirm2018]

Yep. It’s a challenging build. The Sandhawk portion has got to be right on or you get a heavy one stage flight and thumbs down. I’ll look into the retainer. What motors did you guys use?

 

[heada]

I haven't flown mine yet but the motors I have planned is Loki I405W staged to Loki I110W moon burner. Eggfinder Quantum doing the staging in the Apogee sled with another one in an av-bay to do dual deploy and a mini GPS in the nose. Drogue less at apogee.

 

[Cameron Anderson]

Yep. It’s a challenging build. The Sandhawk portion has got to be right on or you get a heavy one stage flight and thumbs down. I’ll look into the retainer. What motors did you guys use?

First flight was AT i305 to CTI i223.
Second flight was AT J420 to AT i435.

Both flights were awesome.
I modified the Terrier to make an av bay.
I also modified the Sandhawk - chopped the fin can and added an av bay.

 

[Faroutspacenut]

Fun and challenging build indeed. I've finished mine but have only done a test flight with a dummy motor in the Sandhawk to check drag separation. Will attempt an actual air start as soon as we can fly again. Also use the giant leap slimline retainer - it works great. Had to sand down the coupler a little bit but I have room for the motor retainer and also the conduit for the e-match that lights the stage motor.

 

[Cameron Anderson]

Fun and challenging build indeed. I've finished mine but have only done a test flight with a dummy motor in the Sandhawk to check drag separation. Will attempt an actual air start as soon as we can fly again. Also use the giant leap slimline retainer - it works great. Had to sand down the coupler a little bit but I have room for the motor retainer and also the conduit for the e-match that lights the stage motor.

Did you get drag sep?

 

[Faroutspacenut]

In fact it didn't. The blow-molded interstage was still a little too snug. I've sanded it down even more. I also think hitting it with a much more energetic boost will help. Separating the stages would be ideal, but I'm ok with letting the sustainer do the work. I've been told the sustainer motor coming up to pressure may be enough to pop it off if drag sep doesn't happen on its own. This is my first high-power staged rocket and my first air start so I'm taking it slow with lots of testing.

 

[heada]

The sustainer will pop the interstage when it ignites. The biggest worry is that since the interstage is plastic, it could melt or deform from the heat. You can mitigate that with a thin coating of epoxy in the inside of the interstage.

I'm going to coat the inside of the interstage and actually pin it to the sustainer so it doesn't drag separate. The Quantum I'm using to stage has 2 events. I'll use 1 at booster burn out to blow the stages apart and then the 2nd to ignite the sustainer.

 

[Cameron Anderson]

In fact it didn't. The blow-molded interstage was still a little too snug. I've sanded it down even more. I also think hitting it with a much more energetic boost will help. Separating the stages would be ideal, but I'm ok with letting the sustainer do the work. I've been told the sustainer motor coming up to pressure may be enough to pop it off if drag sep doesn't happen on its own. This is my first high-power staged rocket and my first air start so I'm taking it slow with lots of testing.

10 grains of 3F black powder is what I use as a sep charge and it's golden.

 

[Gramparocket]

I picked up a kit last month during my visit to LOC for an open house tour.
I got the standard av/bay with it. This is my first HPR two stage.

 

[hambirm2018]

Did you get drag sep?

I have it set up for the drag sep. I went to a Party Store and bought a birthday straw for the wire run. I have not launched it yet, as I am double checking everything. All of these pointers are awesome!!!

 

[Cameron Anderson]

I have it set up for the drag sep. I went to a Party Store and bought a birthday straw for the wire run. I have not launched it yet, as I am double checking everything. All of these pointers are awesome!!!

I always hope for drag sep but haven't got it yet (might have once but didn't have a camera on that flight to verify). I lean towards better stability and a tighter fit and needing a sep charge as opposed to guaranteed drag sep.
Have you looked into taperwire to pass your sustainer ignitor down? I got some for my next two stage project (Two Madcow 54mm Adventurers with 38mm motor mounts)

https://www.amazon.com/s?k=taperwire&sprefix=taperwir&ref=nb_sb_ss_ts-apa-p_1_8

 

[hambirm2018]

FRANKEVER Super Flat Speaker Wires/Cables,Self Adhesive Speaker Cables, 2 Pure Copper Conductors, DIY Audio Cable,23 Gauge AWG, 0.63 inch Wide x 25 ft. Long https://www.amazon.com/dp/B07K859Z4F/ref=cm_sw_r_cp_api_i_0xPwFbAABEFHS

 

[Gramparocket]

Please explain how that wire is being used. If you can post some pics that would be awesome too. I'm building my Terrier right now and still hashing things over for the sustainer. I had already though of slimline retainers as i have used then prior on builds with boattails. I'm still thinking about the Apogee e/bay. More now because my RRC3 came with the sled and it doesn't fit the LOC e/bay. Either way i have order parts