Scratch - 3D Mega Daddy (3D MD) {Scratch}

Scratch 3D Mega Daddy (3D MD) Modification

Scratch - 3D Mega Daddy (3D MD) {Scratch}

Contributed by Steve Lindeman

Construction Rating:
Flight Rating:
Overall Rating:

Published:	2015-08-19
Manufacturer:	Scratch

Brief

I was playing around with my Estes 'Big Daddy' one day when I discovered that its NC would fit the tube that my Aerotech Initiator came packed in. The decision was then made to acquire another Big Daddy and build the 3D Mega Daddy (3D MD).

3D MD

Components

Only 3 components were used from the Big Daddy:

Nose Cone
Main Body Tube
Motor Retention Clip

From the Initiator Starter Set:

Just the 3" x 25.25" packing tube that the main body of the Initiator came in

The rest of the components were either handmade or came from my stock supplies. They include:

10' 1/4" Elastic cord
36" 12 Strand round pink parachute (24" 6 strand yellow hexagon in photo was before I ran the sims to find out what size I needed)
Handmade 3" x 5" tube coupler/baffle
4 - 3/16" x 3" Plywood discs (2 for MM and 2 for baffle)
1 - #8-32 x 1-5/8 in Eye Bolt with nuts
4 - 1/8" Plywood fins
3 - 6" BT-50 tubes
2 Additional Estes 'E' clips
3 - 1/4" Motor Stops (These were cut from a used 'E' motor and not shown because I already had them installed.)
2 - 1/4" Launch Lugs (handmade and not shown in 1st photo)

Construction

Total construction time for this project took a little over 2 years. This was the only Con: and was because I had to make a decision early in the build whether to build a slightly shorter version without the Big Daddy BT with the possibility of only 3 fins as I was going to make this a 3 engine bird. That would make all 3 fin roots the same length and easier to glue to the MM. But after sleeping on it for a few weeks (more like a month or two) and the fact that I didn't want to have to cut new slots in the Aerotech tube, plus I wanted this rocket as big as possible, I finally settled with using the Big Daddy BT and going with the 4 fin configuration. Full detail of this build can be found here at http://www.rocketreviews.com/mega-3d-daddy.html.

Finishing

Finishing was done in my normal fashion. First I went over all spiral grooves with HobbyLite by Hobbico. This has been my goto filler since the 80's when I was building gas powered balsa airplanes. Great stuff to work with. Rocket was then given the usual prime, sand, prime, sand, and main coats. Lastly the body tube was masked off and the flames added. After that entire rocket was sprayed with Dupli-Color Clear Effex paint to give it that rainbow effect.

No Cons:

3D MD Glamour shot

3D MD Glamour shot

Construction Score: 5

Flight

Rocket currently has 3 flights logged. 2 on D12-5's and 1 on E9-4's. All 3 flights have been picture perfect. No Cons:

3D MD Launch

3D MD Launch - All 3 motors lit

Recovery

The main Con: is the 36" round nylon parachute I'm currently using is more than adequate for the job. Simulator says that I needed a 33" parachute but I'm walking further than I like for recovery, especially on the E engines (about 1/2 mile). On the plus side, I'm not getting any major damage from landing on hard surfaces. I may end up swapping it out for a smaller 'chute or at least a different style.

3D MD under chute

3D MD under 'chute at Graves Campgrounds M.I.S.

3D MD recovery

3D MD recovery near exit to camp grounds

Flight Rating: 4

Summary

This was an interesting and very gratifying build and I learned a couple new things along the way. The homemade baffle I installed seems to be working perfectly as I haven't found any damage to the parachute yet. Wish I could see how the aluminum coating on the bottom of the baffle is holding up.

Would love to try 3 composite motors like the 24mm Aerotech F32-6T but besides being hard to get all three composites to light at once, I'm afraid I might lose her unless I can find a much larger launch field and I spent way to much time building her to chance it. Maybe someday if conditions are right and I can afford the motors (that being the major factor).

Overall Rating: 5