4" HOJO

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DragonRocketry

DragonRocketry

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I have one 4" Honest John kit. I had made a kit for a friend and had some extra parts, so I put one together. If there is enough interest, I will keep this in stock on my site. The decals are for the black and white version.

hojo kit.JPG


4in honestjohn.jpg
 
jmasterj said:
Any chance of 3D-printed spin motors or that perforated ring in the middle of the airframe?
Click to expand...
Aerobotix (aka Kevin Cespedes) offers the spin motors for 3.9" LOC tubing on Shapeways.

https://www.shapeways.com/product/F...uot-loc-tube?li=marketplace&optionId=62804727
The motor splice band is also available in a BT-80 size, perhaps he can offer an upscaled version if you inquire...

https://www.shapeways.com/product/V...r-bt80-tube?optionId=174526412&li=marketplace
 
I am starting a build of this kit today for the Dragon Rocketry Honest John. Photos to follow. Nice Loc style carboard kit. I have designed and printed the motor band using Fusion 360. I also printed out the scale spin motors from the OpenSCAD file that is available. The kit come with a nice, printed motor retainer but I will be using Aeropac like I normally use.
 
Not too much done today. Spent quite a bit of time behind the drum kit. I did manage to get the motor mount assembly complete using 25 feet of the recovery harness Chris's Rocketry Supply's had on sale. Tomorrow, I plan on beveling the .250 plywood fins and getting them glued in place. There is a nice plywood fin guide included with the kit, so I don't have to print one.
 

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I installed the motor mount this morning. After beveling the fins on the router out in the shop they are getting glued in place. Notice the nice fin jig included in the kit. The motor band along with 2 other bands will be glued in place after I remove the fin jig when the glue sets up.
 

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Finished up assembly today by laying down the fillets and gluing the parts I printed in place. Will have to wait until nice weather to fill and paint. Still have to drill holes and put rail buttons and standoffs on also.
 

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Brent said:
Finished up assembly today by laying down the fillets and gluing the parts I printed in place. Will have to wait until nice weather to fill and paint. Still have to drill holes and put rail buttons and standoffs on also.
Click to expand...
That looks sweet! Did you make the files for the extra parts?
 
DragonRocketry said:
That looks sweet! Did you make the files for the extra parts?
Click to expand...
I
DragonRocketry said:
That looks sweet! Did you make the files for the extra parts?
Click to expand...

I made the files for the bands but the spin motor files were a scalable OpenSCAD file. Not sure if it was on Thingiverse or where I found it. I originally used it to print spin motors for a 2.6 Madcow kit a couple years ago. I also printed some for a friend's 7.5 inch Honest John.
 
Thanks to the help from Brent, the HOJO kit from this point on will include the spin motors and body bands. Now the bad news, the price has gone up $10 on the kit and also it will be a week or so till I have anymore because someone forgot to place a lumber order (ya that is me..LOL) I thought I still had a box of 1/4" but it is 1/8".
 
Last edited:
How much to get the spin motors for the one I bought last month :) Also, are you using PETG?

Also, if anyone is questioning whether to order from DragonRocketry or not, here was my experience. Everything was packed VERY well, the 3D printed nosecone was done very well, also included in the box was a 3 and 4 fin plywood mounting jig for 4" or smaller tubes as well as a 3D printer screw on engine retainer. Can't wait to get started on it now that I have my Level 3 rocket and paperwork done.
 
conneryc said:
How much to get the spin motors for the one I bought last month :) Also, are you using PETG?

Also, if anyone is questioning whether to order from DragonRocketry or not, here was my experience. Everything was packed VERY well, the 3D printed nosecone was done very well, also included in the box was a 3 and 4 fin plywood mounting jig for 4" or smaller tubes as well as a 3D printer screw on engine retainer. Can't wait to get started on it now that I have my Level 3 rocket and paperwork done.
Click to expand...
Yes to petg. If you go to the nose cone page, I have the spin motors and body rings listed as a package.

Thank you
 
Has anyone done a rocksim file for this Honest John?
 
I scaled up an Honest John file that I had and changed a few things. It should be close enough.
 

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Nice flight. Mine did not go so well. I flew it on a CTI Pro 38 I 303 with the delay trimmed to 8 seconds and the ejection charge on the motor was extremely weak. It barley pushed the nose cone off the tube and the chute did not deploy. I have two of those loads left and I defiantly use them on a dual deploy rocket.
 
conneryc said:
Very Nice! Did you build yours as dual-deploy or did you have a long recovery walk? I'm working on mine now and have built it for dual deploy. Glassed the tube so it will be nice and strong for a big motor :)
Click to expand...
Put an altimeter in the Nosecone for apogee deployment. Chute release for the main. Also upgraded motor tube to 54mm.
 

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