Custom Bullet Upscale?

[Back_at_it]

Finally flew my Custom Bullet #10015 for the first time this weekend. Built it 15 yrs ago and never flew it until yesterday. Flew it on a B6-4 then a C6-3 using an 18 to 24mm adapter. After two successful flights, I'm thinking I want an upscale version. Thinking of building something to fly on a 29mm.

My thoughts are to do a BT70 main tube with a BT60 inner and BT50's for the out board tubes. Has anyone done an upscale Bullet that wants to share?

 

[MALBAR 70]

I've never done an upscale, but a BT70 based Bullet would be cool. Go for it!
This thread reminded me that I have one in the build pile. I dug it out this morning and will start on it tonight.
I like Custom Rockets kits, some of them would make excellent upscales. I have always wanted to do a BT70 based Ion Pulsar...someday...

 

[cwbullet]

Do you have a rock sim?

 

[neil_w]

Wait, what would be the function of the BT60 inner?

 

[MALBAR 70]

Wait, what would be the function of the BT60 inner?

Under the side pods, the main BT is necked down to a smaller size, then back up to it's original size.

Photo courtesy of Rocket Reviews

 

[neil_w]

Ah, didn’t notice that.

Nice looking rocket, should work great as an upscale.

 

[Back_at_it]

I don't have open rocket but i have done the math by hand. The upscale to BT70 will use a 1.67 multiplier.

Upper tube will be 30.0"L.
Lower tube will be 10.0"L.
The gap with the exposed BT60 will be 1.67"L.
BT50 side tubes will be 4.60"L.

Over all the upscale should come in just a touch over 50 inches. Planning on building with a 29mm mount. Should fly nicely on an E16-4.
Planning to do a Baffle and separate it somewhere in the center to avoid having to do a stuffer tube.

Need to find a suitable nose cone. Been looking on ERockets and have a couple of options. Really wish there were more plastic options for BT70's. I'm probably the only person in the world that doesn't like balsa nose cones.

 

[Back_at_it]

I've never done an upscale, but a BT70 based Bullet would be cool. Go for it!
This thread reminded me that I have one in the build pile. I dug it out this morning and will start on it tonight.
I like Custom Rockets kits, some of them would make excellent upscales. I have always wanted to do a BT70 based Ion Pulsar...someday...

Do a build thread on the bullet.

 

[MALBAR 70]

Do a build thread on the bullet.

I'll consider it. I never did end up working on it last night, life (and toilet repairs got in the way). I will get to it this weekend. It's on the bench at least.

 

[Back_at_it]

Finally finished this one up.

Total length 54inches.
Nosecone - 11.0"
Upper Tube - BT70, 30.0"
Lower Tube - BT70, 10.0"
Inner Tube - BT-60, 20". Exposed area 2.0"
Side Tubes - 29mm, 4.50"
Plywood centering rings.
Motor Tube 29mm, 20.0"
Estes 29mm motor retainer.
Fins are 1/8" Basswood.
24" nylon chute.
500# kevlar cord.
3/8 Elastic cord, 12.0'
Built using entirely 30 min epoxy.
Final weight is 14oz empty.
When I checked and compared CG of the two rockets they were within a .500" when scaled.


Shown with it's little brother that was build about 15/16 yrs ago but only recently flew.

 

[neil_w]

Really nice!

 

[MALBAR 70]

Wow, that turned out spectacular!

 

[Back_at_it]

Old thread but I finally got these out to fly. Had a chance to fly both the original and the upscale.

Original flew on a new C5-3 using an Estes adapter. Delay was a tad quick but overall a good flight. Sim'ed at 530ft. and I believe that it got every bit of that and more.

Upscale flew on an Estes E16-4. Left the pad hard and easily flew to 500ft. Ejection was perfect and it came down nicely on a nylon 24" chute.

 

[BABAR]

Old thread but I finally got these out to fly. Had a chance to fly both the original and the upscale.

Original flew on a new C5-3 using an Estes adapter. Delay was a tad quick but overall a good flight. Sim'ed at 530ft. and I believe that it got every bit of that and more.

Upscale flew on an Estes E16-4. Left the pad hard and easily flew to 500ft. Ejection was perfect and it came down nicely on a nylon 24" chute.

View attachment 437901View attachment 437902View attachment 437903View attachment 437904

Few yards off to one side of the pad and you may have required a U.S. Navy recovery!

 

[Back_at_it]

Yeah. Wind was almost 0 at ground level but blowing away from the pond at 100ft up.

problem is that there’s is a gravel road about 20 ft left of the pad. The hard part was getting them up far enough to get them past the road and into the grass.

Most rockets landed between 100-300ft from the pad. But a couple came down on the gravel. It was a perfect day to fly.