Return of Fat Boy

the model rocket show
eggtimer rocketry
the rocketry show
Wildman Rocketry
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
jsargevt

jsargevt

Well-Known Member
Joined
Jun 18, 2011
Messages
1,550
Reaction score
7
Hey all - after losing the body (but recovering the all-important nose cone) of my Fat Boy at CMASS on a D10, I was determined to resurrect the Fat Boy.

So....ordered up some BT-80, a motormount, and some basswood stock. Cut out some stock-sized fins, cut and slotted the BT-80 and built the motormount. I used a little 5 min epoxy to attach the fins.

I thought that it came out pretty nicely!

74c4a479.jpg


6b3263e6.jpg


Should be pretty exciting when I toss it up there!
 
Very cool! I did the same thing, see this thread it has flown on a D12 and 4 C6s all but one motor lit and it still screamed off the pad.
 
Keith,

NICE! Great paint job by the way. I, obviously, need to put some paint on it but with winter weather finally here I suspect I'm a few months away from doing any painting. I really need to build a garage! On the other hand i can get some time to consider some cool painting options.

On my sim I think that i'm looking at 5-6oz in the nose for D12/C6 combo. I did not install a baffle so I don't have that extra weight to offset.

It should be a good launch when I get the chance! Thanks for the linky!
 
It seems that the FAT BOY is a common rocket to make modifications to; as far the motor(s) configurations. I was thinking about building one too. It would be kind of neat to build a booster stage for it. I was thinking about (4) 24mm's ... it would probably really push it high!

Great job on the build!
 
KHamel said:
Very cool! I did the same thing, see this thread it has flown on a D12 and 4 C6s all but one motor lit and it still screamed off the pad.
Click to expand...

Just curious, how do you know what "C" motors to select to match with the D12 burn time and ejection... or maybe an E motor?
 
Looks to me you are going to try and lose it again with that power plant you put in it.
Anywhoo- Nice job on the fin bevels. Nice and clean and even.
 
RocketManDan said:
Just curious, how do you know what "C" motors to select to match with the D12 burn time and ejection... or maybe an E motor?
Click to expand...

The Estes C6 and D12 have a similar burn time see D12 and C6 data sheets from the NAR web site. I think I used a D12-5 and 4 C6-5s.
 
KHamel said:
The Estes C6 and D12 have a similar burn time see D12 and C6 data sheets from the NAR web site. I think I used a D12-5 and 4 C6-5s.
Click to expand...

Thanks...

I just remembered I have some 3x24mm center rings for a BT-80. I could use those.
 
RocketManDan said:
It seems that the FAT BOY is a common rocket to make modifications to; as far the motor(s) configurations. I was thinking about building one too. It would be kind of neat to build a booster stage for it. I was thinking about (4) 24mm's ... it would probably really push it high!

Great job on the build!
Click to expand...

I have built a few Fat Boys, a two stage, a 4 by 18mm cluster, a single 24mm and a 4 by 24mm cluster as well as the one referenced above.

See here and here.
 
KHamel said:
That will work! Good luck with the build we will need to see pics!
Click to expand...

I will get to it...

I have a bunch of kits I should really build or sale? Haven't decided yet?

I should just stay with scratch building:)
 
Scotty Dog said:
Looks to me you are going to try and lose it again with that power plant you put in it.
Anywhoo- Nice job on the fin bevels. Nice and clean and even.
Click to expand...

Thanks Scotty Dog! I was happy with the bevels (for once!).

I would have recovered the other fatty had the estes shock cord not given out. Man I do NOT like the boing cords - I got 3 flights out of the original. I took care of that for this build and used Kevlar. Based on where the nose landed I am sure that the body is somewhere in the woods in Acton but I didn't want to try to find it.

I am pretty confident that I'll get this one back (eventually). If not I have more tubing and another kit in the closet.

Regarding the burn time - the D12 and C6 is pretty close so I'm confident that it will work out. If not what is the worst that happens? :)
 
Very nice...

Why is the nosecone so important?? You can pick up the PNC-80BB (which is the cone used) on practically any hobby store shelf... VERY common cone!

It's the "pointier" 80K cone (like that used on the Phoenix missile or V-2) that's MUCH harder to find! (though others are producing it now so even that's not a big deal anymore).

Later! OL JR :)
 
Which launch did you lose it? Was this the Yellow Fat Daddy? Got pic's or video?
 
KHamel said:
I have built a few Fat Boys, a two stage, a 4 by 18mm cluster, a single 24mm and a 4 by 24mm cluster as well as the one referenced above.

See here and here.
Click to expand...

Did you use tumble recovery on the booster or did you use parachute(s). I would think there would be some damage to it? I launch at a dry lake bed and was considering doing a booster stage with it, but need a chute for it. The surface is pretty hard and would probably break a fin or two? I'm undecided on the 3x24mm or just go with a single 24mm. Probably cheaper to fly it for sure and I would have some choices of composite motors. I would probably add an inch or two to the length to accommodate a longer engine mount tube.
 
RocketManDan said:
Did you use tumble recovery on the booster or did you use parachute(s). I would think there would be some damage to it? I launch at a dry lake bed and was considering doing a booster stage with it, but need a chute for it. The surface is pretty hard and would probably break a fin or two? I'm undecided on the 3x24mm or just go with a single 24mm. Probably cheaper to fly it for sure and I would have some choices of composite motors. I would probably add an inch or two to the length to accommodate a longer engine mount tube.
Click to expand...

It is tumble recovery were we launch the grass is fairly soft, the booster is 24mm.

dlazarus6660
Which launch did you lose it?
Which launch did you lose it? Was this the Yellow Fat Daddy? Got pic's or video?

It was the 4by 24mm launched in Amesbury a few years ago, I had video but have no clue where it is. The Fat Daddy is not my rocket I think the one you are thinking of is ............. ok I am have a brain drain.......I forget who owns but it is very cool I think it's a 19 motor cluster 5" Fat Man.
 
How much nose weight are you guys putting in your clustered Fatboys? I ask, because I built one in my early BAR'dom with a 3X 24mm MMT. I kept adding noseweight until I got back to the CG of the stock kit with a C6-5 motor and the nosecone seems like a lethal projectile (lead weights covered in epoxy). I flew it once and 2 of the 3 D12's lit and it did a 'nice' ballistic arc into the ground a few hundred feet in the safe direction. I was happy it went that way, but I have never flown it again, as I think the nosecone is too heavy.

Looking for thoughts, as I wouldn't mind flying it again if I could lighten the nosecone and use a softer type of weight.

Sandy.
 
OL JR - Ah I was being somewhat sarcastic about the nosecone - although out of any given kit it is typically the more difficult/expensive piece to replace. Had I not recovered the nosecone I'd probably have just not worried about rebuilding the rocket. In this case I concede that the 80BB is easy to find anywhere.

Sandy - RockSim says about 6oz in the nose will get its stability on target. I agree that you probably ought to revisit that one if you decide to launch it again. Its pretty easy to get a new nosecone :wink:. When I get a chance to balance it out I'll let you know what the final number was.
 
Sandy H. said:
How much nose weight are you guys putting in your clustered Fatboys? I ask, because I built one in my early BAR'dom with a 3X 24mm MMT. I kept adding noseweight until I got back to the CG of the stock kit with a C6-5 motor and the nosecone seems like a lethal projectile (lead weights covered in epoxy). I flew it once and 2 of the 3 D12's lit and it did a 'nice' ballistic arc into the ground a few hundred feet in the safe direction. I was happy it went that way, but I have never flown it again, as I think the nosecone is too heavy.

Looking for thoughts, as I wouldn't mind flying it again if I could lighten the nosecone and use a softer type of weight.

Sandy.
Click to expand...

Here is the thread on TRF1 regarding the 4 by 24mm Fat Boy. I used 4.4 oz of nose weight. I also cut off the base of the nose cone and pack the chute there. The 24mm and 4 by 18 mm has 4 oz of nose weight with the base of the nose cone cut off. Both flew very well.
 

Similar threads

Bruiser
GAR 1 Quick Build
Replies
9
Views
377
Bruiser
Bruiser
BigMacDaddy
Fat Man Atomic Bomb Semi-Scale Model Rocket (3D printed + internal tubes)
Replies
27
Views
1K
BigMacDaddy
BigMacDaddy
Back_at_it
Estes Fat Boy 29mm rebuild.
Replies
14
Views
1K
RobertH3
RobertH3
KenECoyote
Yet "Another" Another Fat Boy XL Build Thread (Fat Boy "XLite")
Replies
26
Views
1K
KenECoyote
KenECoyote
86mustang408w
Boosted Big Daddy.
2
Replies
31
Views
2K
86mustang408w
86mustang408w

Latest posts

Back
Top