Short fat rockets

[hball55]

I wanna be cool, so I’m building a 54mm Big Daddy.

I wanna be cool, so I’m building a 54mm Big Daddy.

AMW/ProX (Robert DeHate) sells a fiberglass Big Daddy with a 54mm mmt. Trouble is, their site has been down for a while. Curtis (Composite Warehouse) supplied the kit, or at least the body tube, I know because I ordered it, it came to me with four fins, but the body tube only had three slots cut. Gloria emailed me and said she would have Curtis send me the correct body tube out pronto, and I had it in days. So, if you contact Robert by email, I’m pretty sure you could order one.

 

[jqavins]

I tried this variation of a Bullet Bill (probably totally naïve and was unsuccessful but still a fun experiment)...

Not sure if it was actually stable (it was stable on a swing test) but arched due to imperfect construction or windcocking (and then crashed due to incredibly heavy nose) or if it was inherently unstable (I think you can maybe see it wiggle and stabilize a number of times).
View attachment 477156

I suspect it's inherently unstable. My torpedo experiment was a failure, which had a somewhat similar concept and failed, and I suspect it had a better chance than yours.

RockSim, which does handle ringtails, said it was stable. A swing test said it was stable, and I was pretty rough with that. The RSO took one look and said it's not stable, but because of the swing test success he'd let me try it from a high power pad (which I'd have asked for anyway, since I wasn't altogether confident either). He was right; it's a sky writer.

Like me, you've got a ringtail with a tail cone inside it. Unlike me, your ring in not all the way down and then you've got more full body tube diameter below the boat tail and ring, which I strongly suspect make the situation worse than mine.

I'll be heading back to the drawing board. If you do the same, perhaps we can share notes.

 

[DigBaddy]

I so love this thread!! Childhood Alien Space Probe. Some legs broke a long time ago, so I amputated the rest. Fixed after lawn dart with new body tube (and 24mm mount) only to lawn dart again on a motor with a bad ejection charge. Just cut off 1.25" of the front of the body tube. It's even more stubby but flies great yet with some nose weight. D12-5 is a do-it-all-day motor for it (550' or so). Need a bigger field to give it an E sometime.

 

[boomtube-mk2]

"Tri-Oomph!!" BT-101 with a custom printed nose-cone. 3x24mm motors.

 

[MikeyDSlagle]

My latest, keeping with the Fallout theme. LOC Mega Magg

 

[bobbyg23]

LOC Minie-Magg I call deep blue

 

[boomtube-mk2]

"Spot On" Bt-80 2x24mm 2x18mm

 

[ThirstyBarbarian]

This is my short, fat rocket named Foamy. Foamy is made of foam insulation board. Diameter 7”, height 48”, weight 4 pounds. Foamy likes CTI I125 motors with a 4.4-second burn.

 

[crossfire]

Here is a Smokin' Rockets Chubsy, 7.5" dia. and 36" tall, that I converted to a Bullet Bill thanks to Mark at Stickershock23 and his decals.View attachment 477181

Is that Bullet Bobbies father?

 

[BABAR]

View attachment 477409View attachment 477413View attachment 477414
"Spot On" Bt-80 2x24mm 2x18mm

So a two motor staged cluster with twin independent boosters, in case they didn’t go off simultaneously they still work.

very clever, I like it. Need some good spotters with three pieces!

 

[BABAR]

Is that Bullet Bobbies father?

Would that be Robert Remington?

 

[hball55]

Is that Bullet Bobbies father?

Actually that is the actual name of the flying bullets in the Mario Brothers video games. It’s trademarked, so Launch Lab couldn’t use the name and chose Bobby instead.

 

[crossfire]

Would that be Robert Remington?

Robert Winchester Jr.

 

[hball55]

I suspect it's inherently unstable. My torpedo experiment was a failure, which had a somewhat similar concept and failed, and I suspect it had a better chance than yours.
View attachment 477204
RockSim, which does handle ringtails, said it was stable. A swing test said it was stable, and I was pretty rough with that. The RSO took one look and said it's not stable, but because of the swing test success he'd let me try it from a high power pad (which I'd have asked for anyway, since I wasn't altogether confident either). He was right; it's a sky writer.

Like me, you've got a ringtail with a tail cone inside it. Unlike me, your ring in not all the way down and then you've got more full body tube diameter below the boat tail and ring, which I strongly suspect make the situation worse than mine.

I'll be heading back to the drawing board. If you do the same, perhaps we can share notes.

Scott Binder sells a rocket that resembles a 50 caliber bullet. I believe the fins are removeable so you can display the rocket as a bullet.

 

[jqavins]

Scott Binder sells a rocket that resembles a 50 caliber bullet. I believe the fins are removeable so you can display the rocket as a bullet.

OK, but I was referring to this:

and comparing it to this:

I'm no firearms expert, but I'm pretty sure that fifty cal rounds don't have ring tails.

 

[boomtube-mk2]

"Bumble-D" Bt-70 24mm two stage. You can clearly see the vent hole for "Gap-staging".
The entire rocket is about 14" long.


The booster uses streamer recovery, otherwise it would come down like a rock.


As you can see most of the booster's motor resides inside of the second stage. The lower portion of the tube is reinforced with a length of tube coupler.

 

[hball55]

OK, but I was referring to this:and comparing it to this:I'm no firearms expert, but I'm pretty sure that fifty cal rounds don't have ring tails.

Ok McDuff, you confused me again. I think I was answering the other guy you quoted.

 

[BigMacDaddy]

OK, but I was referring to this:and comparing it to this:I'm no firearms expert, but I'm pretty sure that fifty cal rounds don't have ring tails.

I was hoping that the angled part of ring tail would create some drag (and direct air outwards concentrically) to stabilize this oddrock.

I considered a few other options -- like making the angled transition all the way to the body so there would not really be a ringtail at all but instead just a cone. I also thought about making the ring tail slide backwards so it would be several inches behind the rocket when it launched. I could even move the engine further forward so that it was just behind nose.

I don't eat enough oatmeal to do too many prototypes though...

 

[jqavins]

Old joke: an Englishman said to a Scotsman oats are not fit food, and in England, oats are only served to horses. The Scotsman said "Aye, that's why the English grow such fine horses and the Scottish grow such fine men!" So eat more oatmeal.

I also thought about making the ring tail slide backwards so it would be several inches behind the rocket when it launched...

Moving the ring back by sweeping the pylons is one of the things I might do for the torpedo.

 

[bronicabill]

I don't really care for the looks of short, fat rockets, therefore I only have one that somewhat meets the criteria, and that is my V2 that is currently awaiting paint. Everything else is longer and much slimmer!

 

[kuririn]

Launched some SFRs* this morning.


* Short Fat Rockets AKA Goonies

 

[boomtube-mk2]

"There Once Was a Rocket From Nantucket"

 

[BigMacDaddy]

Does a Convair XFY Pogo VTOL Plane count as a short fat rocket??? Figured I would give it a go after the successful launch of the Coléoptère... I just built this but have not yet tested it. I decided to make it with a pair of mini engines to maintain the look of the prototype (also figured that would give it some good punch since I knew I would need nose weight, trying with 1/2 oz for now which puts CG around 2cm behind front of larger fins/wings).

 

[Cape Byron]

Does a Convair XFY Pogo VTOL Plane count as a short fat rocket??? Figured I would give it a go after the successful launch of the Coléoptère... I just built this but have not yet tested it. I decided to make it with a pair of mini engines to maintain the look of the prototype (also figured that would give it some good punch since I knew I would need nose weight, trying with 1/2 oz for now which puts CG around 2cm behind front of larger fins/wings).

I'd yell "KIT!" again, but it's getting repetitive. ❤

Great work (again) with a super cool subject (again)!

 

[BigMacDaddy]

I'd yell "KIT!" again, but it's getting repetitive. ❤

Great work (again) with a super cool subject (again)!

haha... thanks... need to get yourself a 3D printer

p.s., I will also do a version of nose cone with removable propeller blades (or maybe easier to just swap nose cones).

 

[Pete.D]

Scott Binder sells a rocket that resembles a 50 caliber bullet. I believe the fins are removeable so you can display the rocket as a bullet.

Not a bullet: it looks more like a .30-06 cartridge, and yes the fin can and fins are removable for display. I've got one half-built. The fin can assembly is actually based on a 38mm motor mount, which slides in and out of a 54mm body tube in the base of the "Bullet" (cartridge) body.

Hmm... so I could attempt a flight on a 54mm motor in place of the fin can, but it certainly wouldn't be stable without fins unless it had at least 10 lbs of nose ballast (Rocksim says such a rig might be stable with a K2050 motor, but I dunno; the RSO would never approve).

 

[hball55]

Not a bullet: it looks more like a .30-06 cartridge, and yes the fin can and fins are removable for display. I've got one half-built. The fin can assembly is actually based on a 38mm motor mount, which slides in and out of a 54mm body tube in the base of the "Bullet" (cartridge) body.

Hmm... so I could attempt a flight on a 54mm motor in place of the fin can, but it certainly wouldn't be stable without fins unless it had at least 10 lbs of nose ballast (Rocksim says such a rig might be stable with a K2050 motor, but I dunno; the RSO would never approve).

Yes, lol, my imprecise language gets me in trouble again. Of course it’s a cartridge, casing & bullet. When I got mine, I was dry fitting some of the parts and two of them got stuck together; panic set in quickly, but I was eventually able to separate the coupler with a towel and pair of vice grips. The towel was used so that the vice grip jaws wouldn’t leave marks. I put it all away and have yet to go back to the kit.

 

[Hobie1dog]

NCR Big Brute, has around 25 flights on it, repainted once due to landing on gravel road, chute dragged it about 200 ft. resulting in severe road rash.

View attachment 406675

this is another kit that I wish they would come back out with.

 

[brockrwood]

Post a pic and name of you favorite short fat rocket.

My favorite is either a fat boy or one I can’t think of the name but it had small brakes on the bottom of the fins to slow and push the CP back.

Don't forget the tiniest short, fat rocket: The Mini Meanie!

 

[cwbullet]

Don't forget the tiniest short, fat rocket: The Mini Meanie!

View attachment 488463

I remember it but never bought one. Great trip down memory lane.