Ye Olde Rocket Forum

Ye Olde Rocket Forum (http://www.oldrocketforum.com/index.php)
-   Projects (http://www.oldrocketforum.com/forumdisplay.php?f=17)
-   -   Build thread: Rocketarium Jayhawk Deluxe (http://www.oldrocketforum.com/showthread.php?t=17524)

jeffyjeep 09-29-2018 04:05 PM

Build thread: Rocketarium Jayhawk Deluxe
 
6 Attachment(s)
I happened upon this kit on erockets site and HAD to have it! I've built the previous (non-deluxe) Rocketarium Jayhawk before, so lets see what's different.

First of all, the boat tail doesn't have to be formed from cardstock. It's 3D printed and has scale surface details.

The decal sheet is far more detailed and more to scale now.

I haven't perused the instructions yet, but it appears there's now an ejection baffle assembly.

The winglets are slot-mounted to the main wings/fins.

Should be fun!

jeffyjeep 09-29-2018 04:51 PM

4 Attachment(s)
Fitting the engine mount into the 3D printed boat tail.

I first sand the mounting places of the boat tail with 220 to give it some grip for the epoxy. The 24 MM engine mount that I've assembled is a nice slip-fit into the boat tail and registers beautifully! I've used mid-cure epoxy for the adhesive.

I then add the wood centering ring to the protrusion of the engine mount tube and epoxy it also.

TBC

jeffyjeep 09-29-2018 09:13 PM

5 Attachment(s)
Now the baffle assembly.

The perforated baffle disks register into the ID of the JT60 baffle body. I've epoxied those in as well as the shock cord screw eye. Once the baffle assembly is glued into the main BT60 it will probably never again be serviceable so I've cut a length of 100# braided Kevlar and tied it to the screw eve with (2) bowline knots and (1) lark's head knot. The supplied shock cord is the rubber kind, so I've rep[laced it with a 1/4" wide braided elastic fabric cord that's 48" long.

I then epoxy the baffle and shock cord assembly into the main BT60. A 4" length of tube is provided in the kit to push the baffle assembly in the correct distance.

Last step for the night. After marking the BT60 for external features I epoxy the boat tail into the main BT60.

Time for some Scotch! Good night.

TBC

LeeR 09-29-2018 11:23 PM

Jeff,

That kit looks nicely done. I’m looking at the tailcone on a smartphone, but zooming in, it looks pretty smooth, with nice detail. Was any sanding required? A year ago it seemed that most 3D rocket parts needed a fair amount of sanding/filling. The quality of 3D parts is just amazing now.

I bought Rocketarium’s aluminum motor retainers in 18mm and 24 mm when they were introduced several years ago. Excellent fit and finish.

jeffyjeep 09-29-2018 11:30 PM

Quote:
Originally Posted by LeeR
Jeff,

That kit looks nicely done. I’m looking at the tailcone on a smartphone, but zooming in, it looks pretty smooth. Was any sanding required? The quality of 3D parts is just amazing now.

I bought Rocketarium’s aluminum motor retainers in 18mm and 24 mm when they were introduced several years ago. Excellent fit and finish.


You’re right. The 3D printed boat tail is pretty smooth. Because of the subtle scale surface details I’m Not going to sand it.

Besides the boat tail, the canards, flare nose cone, and antennas are also 3D printed.

LeeR 09-29-2018 11:33 PM

Thanks for responding tonite. Now please go ahead and finish that scotch, and go to bed. ;)

BARGeezer 09-30-2018 01:49 AM

Hard to tell from the pictures, but looks like they may have a thicker shock cord than the older model? The older version had a lot of clay ballast making the nose cone quite heavy. On my first flight the 1/8" elastic snapped and the rocket came down horizontally less chute. Sustained cracks to the winglet glue joints.
These winglets apparently have a reputation for landing damage. Don't remember if it was the Rocketarium instructions or Madcow's, but it said there are two schools of thought: Tack on the winglets and deliberately have them pop off at landing, minimizing damage and repairs. Or, do the traditional strong glue bond. But if they get damaged, repairs will be more extensive.

jeffyjeep 09-30-2018 09:25 AM

1 Attachment(s)
Good morning shipmates.

The nosecone is stuffed with a huge block of supplied plasticine(?) and 1/2" of epoxy and it weighs a whopping quarter pound! The supplied shock cord was indeed 1/4" wide, but it was white rubber--which I promptly replaced with 1/4" braided elastic fabric and 48" long.

My theory is: after ejection and laundry deployment (assuming the shock cord doesn't separate) the weight of the nosecone will cause the nose cone to recover physically lower than the rest of the model--with it's fragile winglets and and antennae.

TBC

jeffyjeep 09-30-2018 10:17 PM

7 Attachment(s)
After a full day of honeydews (not the melons,) I can finally dedicate a few minutes to the Jayhawk Deluxe.

In step 7 of the instructions it states: "If you do not feel comfortable tapering the fins then round the leading edge of all wings and fins". Sheesh! On my worse day I can scrape a taper into a stinking fin! How think do they drunk I am?

The full-size fin pattern sheet shows how much to taper the fins and winglets. Using the outside measuring jaws of the dial caliper, I pierce tiny marks into the balsa at (2) places on each edge at the correct distance. I then simply draw a line across the marks to indicate the bevel line.

I'll start with the winglets. Using the Corian slab that's covered with 220 grit, I scrape only the outer edges of the leading edges of the winglets.

I think I've had too much Scotch. I'll do the rest of the bevels tomorrow.

Time for some Scotch. Good night! TBC

jeffyjeep 10-02-2018 07:52 PM

4 Attachment(s)
Back to the tapering.

Scraping the inside bevels of the winglets is a little harder. It's a good thing there's a full size balsa pattern sheet included!

Again using the Corian slab I scrape the bevels into the inside miter cuts of the winglets and then I clean up the horrible job I did of scraping with the mahogany block.

Both winglets are shaped now. I don't know if I'm satisfied with them and I might do them over--but in basswood. I'll see how t hey look on the main wings after the main wings are shaped. TBC


All times are GMT -5. The time now is 06:11 AM.

Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.