Anyone fly an Apogee Katana Jr.

[darrenf]

Just received this kit from Apogee as I'm looking to start messing around with dual deploy in something small that I can fly locally and inexpensively. I have an Eggtimer Quark on the way that I plan on loading inside to manage the flight events. Any tips would be welcome.

 

[Desfossr]

I got mine for the same reasons you did. Mine is built and waiting for paint - it’s been too cold outside and I’m not allowed to paint indoors . I have an Altus Metrum EasyMini installed but have not yet ground tested - it’s been too cold outside and I’m not allowed to blow things up in the house. My calculations indicate the charges should be about 0.2g of ffffg black powder. Once I do get to test this, I’ll let you know. The build itself was pretty straight forward. The fins are three pieces but you can only assemble them one way. Just be sure to get them flat.

 

[waltr]

This is about the same size as a couple of LOC rockets I fly with DD. These are 2.3 inch diameter (IRIS & LaserLOC).

They need about 0.8gram BP for Drogue and 1.2gram BP for main with one 2-56 nylon shear pin holding on the nose cone.

I never have found any of the charge calculators to give the correct amount of BP for these smaller rockets.
Do try starting at 0.3 gram but I think you will need to increase the amount. Then when it works with ground testing increase to amount a bit more to ensure it works in flight.

 

[David_Stack]

My dual-deploy Partizon derivative sees me using 0.6 grams of 4f BP on both the drogue (volume 2.5" x 15") and main (volume 2.5" x 13"), nose cone is friction fit...

https://www.rocketryforum.com/threa...a-project-ddt-dual-deployment-trainer.172528/

 

[darrenf]

I got mine for the same reasons you did. Mine is built and waiting for paint - it’s been too cold outside and I’m not allowed to paint indoors . I have an Altus Metrum EasyMini installed but have not yet ground tested - it’s been too cold outside and I’m not allowed to blow things up in the house. My calculations indicate the charges should be about 0.2g of ffffg black powder. Once I do get to test this, I’ll let you know. The build itself was pretty straight forward. The fins are three pieces but you can only assemble them one way. Just be sure to get them flat.

I've got the motor mount in, hoping to assemble and mount the fins tomorrow. I hope you get better weather soon. Weather today was absolutely perfect and if I had her ready to fly I would have been out with her.

 

[darrenf]

This is about the same size as a couple of LOC rockets I fly with DD. These are 2.3 inch diameter (IRIS & LaserLOC).

They need about 0.8gram BP for Drogue and 1.2gram BP for main with one 2-56 nylon shear pin holding on the nose cone.

I never have found any of the charge calculators to give the correct amount of BP for these smaller rockets.
Do try starting at 0.3 gram but I think you will need to increase the amount. Then when it works with ground testing increase to amount a bit more to ensure it works in flight.

This is very helpful, should keep me from blowing the thing up before it even gets off the ground. Thank you.

 

[Desfossr]

I've got the motor mount in, hoping to assemble and mount the fins tomorrow. I hope you get better weather soon. Weather today was absolutely perfect and if I had her ready to fly I would have been out with her.

Congratulations on your recent L1 cert. - I just noticed the date. Weather is shaping up and I’ve started the finish on my Zephyr. Hope to certify in the next couple months. I’ve got an H-100 for the job. How the Katana Jr coming?

 

[darrenf]

Congratulations on your recent L1 cert. - I just noticed the date. Weather is shaping up and I’ve started the finish on my Zephyr. Hope to certify in the next couple months. I’ve got an H-100 for the job. How the Katana Jr coming?

Thank you. Best of luck on your attempt. Fins are on and first few coats of primer are applied. I’m awaiting delivery of my egg timer order so I can get to soldering the flight computer.

 

[Desfossr]

Ground tested the drogue side today. Used an Eggtimer Quantum in test mode to activate the charge. The Quantum was not in the rocket but connected to the ejection charge through the vent hole. My charge was 0.18 grams of ffffg blackpowder in a centrifuge tube, then packed with “ dog barf” and taped closed. It worked perfectly.

 

[darrenf]

I was hoping on flying last weekend, but 4 days of rain, the humidity wreaked havoc on my tubes. The ebay was basically welded into the booster section, so thee was no way I could fly. In fact, just trying to get it apart really strained the holes in the upper section where the plastic rivets were. I emailed Apogee to try to get some advice and lets just say they were less than helpful. Their "solution" was to sand the ebay until it fit easily again. The problem is twofold, one that tubing is super thin, and two, sanding it just releases the fibers, making the two tubes grab each other even more tightly. After several days of the sanding getting me nowhere (about an hour of sanding a night) I decided to thin CA the tubes, and then sand that CA to a super smooth finish. It took me two more nights of sanding, but as of tonight everything moves smoothly and easily again. I can't really be sure whether I helped it, or the 5 dry days since have had the most impact. I really feel in their effort to make this as cheap as possible, the uber thin tubes, push this kit into almost garbage territory. The brush off I got from Apogee was just icing on the cake. I really wasn't expecting that. Oh well. I'm hoping to get another chance to fly it this weekend. I'll report back once I do.

 

[MidOH]

Yep. Always CA seal your tubes (not aft edge by the motor). And when she's complete, seal the insides with polyurethane. Paper rockets always land in water.

CA seals and strengthens the trailing edge of fins nicely as well.

 

[SDrocketman]

This is about the same size as a couple of LOC rockets I fly with DD. These are 2.3 inch diameter (IRIS & LaserLOC).

They need about 0.8gram BP for Drogue and 1.2gram BP for main with one 2-56 nylon shear pin holding on the nose cone.

I never have found any of the charge calculators to give the correct amount of BP for these smaller rockets.
Do try starting at 0.3 gram but I think you will need to increase the amount. Then when it works with ground testing increase to amount a bit more to ensure it works in flight.

https://rocketrycalculator.com/rocketry-calculator/bp-estimator/

 

[darrenf]

So I flew it finally. Turns out the switch was bad and turned my altimeter off when the drogue was fired. I did notice the switch was a little touchy when I first installed it, but it didn't click with me to make sure it could handle the shock of an ejection a few inches behind it. And when I ground fired it it didn't occur to me that it turned off because I was only firing one charge at a time and wasn't polling the altimeter afterward. Fortunately the field was nice soft grass and everything recovered fine. Again, Apogee was less than helpful, just insisting that they don't replace parts once flown. So, I ordered a pull pin switch from Lab Rat Rocketry and now have that installed. Going to be trying it again this Sunday. Here she is with the pin flag.

 

[Rocketjunkie]

Twist and tape down. Never had a failure in over 1000 dual deploy flights. Only high performance rockets get switches where nothing sticks out into the air flow.

 

[darrenf]

Twist and tape down. Never had a failure in over 1000 dual deploy flights. Only high performance rockets get switches where nothing sticks out into the air flow.

I'm going to stick with the switch. One, it looks awesome, and two, this is a vehicle for me to learn the techniques I'll need on larger rockets down the road.

 

[novahobbies]

Bit disappointed in the customer service you've been getting from Apogee! I was thinking of getting this, and their X-15......now I'm less certain!

 

[darrenf]

Bit disappointed in the customer service you've been getting from Apogee! I was thinking of getting this, and their X-15......now I'm less certain!

Yeah, that hasn't been my experience up to now, but dealing with them for these last two issues has definitely left a sour taste in my mouth. If I were to do this again, I'd go with the LOC Deployer. The added inch of diameter makes things a lot easier when it comes to setting up the electronics too. And still light enough to fly locally.

 

[Desfossr]

So I flew it finally. Turns out the switch was bad and turned my altimeter off when the drogue was fired. I did notice the switch was a little touchy when I first installed it, but it didn't click with me to make sure it could handle the shock of an ejection a few inches behind it. And when I ground fired it it didn't occur to me that it turned off because I was only firing one charge at a time and wasn't polling the altimeter afterward. Fortunately the field was nice soft grass and everything recovered fine. Again, Apogee was less than helpful, just insisting that they don't replace parts once flown. So, I ordered a pull pin switch from Lab Rat Rocketry and now have that installed. Going to be trying it again this Sunday. Here she is with the pin flag.View attachment 583486

Looks like you did something different with the rivets. Yours don’t appear to be what is provided with the kit.

 

[ShadowSpire48]

Yeah, that hasn't been my experience up to now, but dealing with them for these last two issues has definitely left a sour taste in my mouth. If I were to do this again, I'd go with the LOC Deployer. The added inch of diameter makes things a lot easier when it comes to setting up the electronics too. And still light enough to fly locally.

I dealt with their customer service a few times and was less than impressed. Couple that with the ridiculous prices they charge for certain things and I stopped buying from them for good. LOC is superior in service and quality

 

[darrenf]

Looks like you did something different with the rivets. Yours don’t appear to be what is provided with the kit.

I had to replace the stock rivets after trying to separate the parts when they were basically welded shut due to humidity. The holes got elongated, so I epoxied nuts in.