Rejected Reality 7.5" Rocket Build!

Did the third set of internals. Since all internals look the same as the first picture I'm not going to post any more but I will take a picture of the completed fin can once I do the last set.

Well, it's been awhile since I updated this thread... and that's because I haven't had much of a chance to do a lot of work. Here's a list of what I have completed.

• Final set of internal fillets. (Pictures to come)
• Base of NC cut off (Pictures to come also)
• Started figuring out how much Nose weight is needed.

After putting every 75mm motor that will fit in this rocket through a simulation, it looks like I need 3 pounds of nose weight. This amount will allow me to fly every 75mm motor up to 35"!

What is still left to do:

• Motor retention ( Going to TSC tomorrow to get the hardware I need)
• Motor Mount into airframe (waiting on motor retention and glueing on the forward CR)
• Rail buttons
• Nose weight added
• Electronic bay -
• Couplers glued in.
• Final weighing
• Charge testing
• Paint
• Flight! :grin:

I may have missed a few things in there as well.

I do have a few questions however:

1. I am currently planning on using steel BB's in the cone for weight, however this option may get expensive. Does anyone else have any other ideas that I could do tomorrow or the next day and get at a store near me (Walmart, Tractor Supply, Sears) ?
2. When I cut the base of the NC off, it allowed the cone to deform. I didn't realize this would happen and it doesn't seem to be a big issue as I just have to squeeze it a little to make it fit into the airframe. What do you think?
3. Is there an easy way to fix this? I can't insert a BP because my main goes in the NC.

I have ordered and received a lot of the supplies I needed for the electronics bay so once I get the rest of it I will likely start on that.

Pictures will come later.

codysmith said:

I am currently planning on using steel BB's in the cone for weight, however this option may get expensive. Does anyone else have any other ideas that I could do tomorrow or the next day and get at a store near me (Walmart, Tractor Supply, Sears) ?

Click to expand...

I've used lead wheel weights before they're denser so you wouldn't need as many and you could (probably) get them at a local auto parts store.

And if you want to get real fancy you could melt them down into one giant block and glue it in!

Well, I promised pictures...
Pic 1) Aft ring looking down
Pic 2) MMT fit into lower airframe
Pic 3) One of the internal fillets.
Pic 4) Top down of MMT into airframe
Pic 5) MMT in it's current state
Pic 6) Nose cone (warped)
Pic 7) Whole Rocket

I was planning on doing the following:

• Scuff up inside of nosecone with rough grit sand paper.
• Wash the inside of the nose cone.
• Drill 1/4" holes in the nose cone near the tip (2 perpendicular sets off center)
• Insert 1/4" dowels
• Using a small amount of epoxy, glue in the 5/16" allthread into the tip
• Mix up a slurry of the BB's and epoxy and pour into the tip.
• Push a bulkhead (size to be determined) on top of the slurry
• Secure the bulkhead to the allthread with a nut

I probably don't make any sense with how I explained it. The reason the dowels are off center is because the allthread needs to be centered in the nose cone for the bulkhead to fit properly.

RAHagen said:

I've used lead wheel weights before they're denser so you wouldn't need as many and you could (probably) get them at a local auto parts store.

And if you want to get real fancy you could melt them down into one giant block and glue it in!

Click to expand...

Good point, at the same time, I would need a lot of wheel weights as they are usually less than an ounce each and I need 3 lbs! I'll look into it though.

Oh, I also glued on the forward CR today too right after I took those pictures.

Crosman Copperhead BB is 5.1 grains. That equates to 4117 BBs (give or take) for 3 pounds. But you also have to add in the mass of the epoxy, which would reduce the number of BBs required.
Maybe a combination of lead fishing sinkers and BBs? Do you live near an outdoors store that sells salt water fishing gear? (Cabela's, Gander Mountain, Bass Pro, etc) Salt water usually means bigger weights. Wally world may have some larger fishing weights as well.
With that much weight, I would add an extra dowel or 2, but then I'm paranoid. Check with Jim and see what he thinks.

You can fix the nose cone shoulder with a piece of tube or coupler if you have it. Cut it lengthwise then trim the cut until it fits inside the shoulder snugly then scuff & epoxy in place. Could also be pinned in place with toothpicks or pieces of bamboo skewers sanded smooth. The best way to get the size you need is put the cut tube in, then draw a line along the cut edge where it overlaps. I would guess you would have to trim about 1/4" or so, but measure it to be sure. (I've not used up all my wrong answers for this year yet.)

Hope it helps.

T-Rex said:

Crosman Copperhead BB is 5.1 grains. That equates to 4117 BBs (give or take) for 3 pounds. But you also have to add in the mass of the epoxy, which would reduce the number of BBs required.
Maybe a combination of lead fishing sinkers and BBs? Do you live near an outdoors store that sells salt water fishing gear? (Cabela's, Gander Mountain, Bass Pro, etc) Salt water usually means bigger weights. Wally world may have some larger fishing weights as well.
With that much weight, I would add an extra dowel or 2, but then I'm paranoid. Check with Jim and see what he thinks.

Click to expand...

Good idea combining the two. I don't live near one of those stores but I will take a look at Walmart tomorrow. I might add another dowel or two, still not entirely sure... I kinda wish I had gotten a FG nose cone... It sure would have made attaching the weight easier.

Last time I bought lead was in a 5 lb piece at a hardware store. They were used to fix cast iron sewer pipe joints. Before that I bought 10 lb bags of lead shot for reloading shotgun shells. Most gun and reload supply places should have that. You can also check with dive shops. I believe they use lead shot in weight belts now.

Ok, I'll definitely be looking at Tractor Supply tomorrow. They should have something.

Well, I went to Tractor supply, got my motor retention, and...... forgot nose weight. Yep, totally forgot about it... I will try to look next time I am in that area. However, I did get the most important part so I can continue working once time becomes available!

:grin::grin:Wow! Can't believe I totally forgot to update this... This build is pretty much finished now with exception for the AV Bay which I will work on this weekend and finish up Monday. I stuck with Primer on body tube and black nose cone and fins. Not too bad for cheap rattle cans.:grin::grin:

I found that the fishing sinkers being split shout reduced density and took up space, same with gun shot. I found by far the cheapest and easiest place to get small round shot was to buy very cheap scuba diving weight bags and cut them open:

https://www.amazon.com/gp/product/B0034ZECX4/?tag=skimlinks_replacement-20

Edit: Just realized how old that part of the discussion was, hopefully someone will find it useful.

Haha! It's fine! I can't remember if I ever ended up posting what I did so I will again.

Basically, I had a hard time paying that much for nose weight, so I went to Tractor supply and bought 3# of 1/4"-20 nuts. I mixed this up as I normally would and poured it in the nosecone with a bulkhead to lid it off... Pretty darn simple and it doesn't look like it's going to pop out especially since I roughed it up well inside and poured epoxy over the bulkhead.

qquake2k said:

I've used nuts in the past, and they work well. My favorite, though, is BB's.

Click to expand...

What? BB's nuts? Is Matt aware of this?

grouch said:

What? BB's nuts? Is Matt aware of this?

Click to expand...

Hahahaha!

grouch said:

What? BB's nuts? Is Matt aware of this?

Click to expand...

I really hope BB's nuts are bigger than BB's. :tongue:

qquake2k said:

I really hope BB's nuts are bigger than BB's. :tongue:

Click to expand...

I doubt it.....

Really... ��

Rocket used to be BBT now it should be BB's-BB's

Now that is something!

Hahahahahahahahahaha

Nate

Has anyone ever tried Deez Nuts?

[video=youtube;5LlQNty_C8s]https://www.youtube.com/watch?v=5LlQNty_C8s[/video]

ThirstyBarbarian said:

Has anyone ever tried Deez Nuts?

[video=youtube;5LlQNty_C8s]https://www.youtube.com/watch?v=5LlQNty_C8s[/video]

Click to expand...

No!

I'm never gonna hear the end of this....

blackbrandt said:

I'm never gonna hear the end of this....

Click to expand...

Now, what makes you think that????