Bwahahahahaaaaa!!! FATBOY!!!!!

[nialloswald]

4 E9's is a nice combination, the long burn is great!

Even better CHAD-stage 2 of the E9's from D12's, gives you ~150Ns of BP power and a ~5 second burn. I've flown this combination 3 times now, with significant horizontal velocity it puts my fairly large and heavy rocket ~1600ft up.

Depending on the weight of the rocket, you might have to watch the wind though - after the intial peak of thrust, acceleration is pretty sluggish. Luckily the D12's hanging off the back give my rocket a small margin of stability, and its not until they drop that it heads into the wind!

https://www.bits.bris.ac.uk/niall/gallery/view_album.php?set_albumName=EARSMarch2005&page=8

The staggered combination of motors makes for an interesting acceleration graph!

 

[melvyn]

Went out to Arginia today (thanks, KLOUDBusters ) and flew both my Fat Boys, one on C6's, the other on E9's. The E9 powered one just kept going and going and going... someone commented that it was like the Energizer bunny. I liked the E flight so much, I went back and did it all again.

I got a bit too ambitious, and tried an Aerotech single use E30 in a Blue Ninja, but had a brain fart and got a motor with a shorter than optimal delay. It went up great, but shredded the 'chute at ejection for heads-up recovery. Gonna try that again soon, but with a nylon 'chute and a longer delay on the motor.

 

[AkitaDog]

Here is a shot of my Fat Boy I built by glassing the BT and cutting new fins from 1/8" plywd.

The motor baffle was cut on our CAM from 1/8" Liteply.

Had to cut the bottom off the nose cone and epoxy some lead shot in to the nose.

It flys on 6 c6-7's and one D12-7.

Just before launch
https://home.inreach.com/akitadog/Fat Boy Cluster1.jpg


Launch, only 4 C' and the D lit.
https://home.inreach.com/akitadog/Fat Boy Cluster 2.jpg

Mark

 

[nialloswald]

Launch, only 4 C' and the D lit.

You want quickmatch

Its exempted by UK regs, however I believe you need a license for it in the USA. If you can get it, its good stuff (tm). Great for clusters in the size between using individual igniters and flashpan ignition.

 

[benjarvis]

I had a Fat Boy (renamed 'Fat Yob') which flew on F101T's... that was a fun little flight

Man that is one fast motor

I bought a second Fat Boy which I intended to carbon wrap and stick an I357T in... but then we lost AeroTech and so it's still sitting in it's bag.


They do scream out to be abused


Ben

 

[powderburner]

Originally posted by benjarvis
I had a Fat Boy (renamed 'Fat Yob') which flew on F101T's... that was a fun little flight

And the fins stayed on?

 

[benjarvis]

Originally posted by powderburner
And the fins stayed on?

Sure did


I admit, the fins were laminated on both sides with paper and polyester resin to make them more rigid, and were glued in place with epoxy rather than wood glue... but I recon it may well have held up as standard if built well.

Oh... amd the motor mount was strengthened as well, IIRC the aft centering ring was replaced with a plywood one.


Ben

 

[andysrockets]

Originally posted by powderburner
And the fins stayed on?

I witnessed it fly... it flew very well indeed. So well in fact, that I nearly bought one myself to do the same, but that wouldn't have been very original.

 

[nialloswald]

I had a Fat Boy (renamed 'Fat Yob') which flew on F101T's... that was a fun little flight

Man that is one fast motor

RTV did one on a G55

Mike 'scary' Hoffman turned up at EARS in December with an estes Big Daddy, complete with wonky fins and launch lug (yes, lug!) big enough to fit a 'C' motor in, and a Pro38 H hanging out the back.

Contrary to the predictions of all assembled, it actually worked - no shred, no skywriting, and a chute!

It wasn't pretty, but it worked.

F101T was 24mm right - so you could get 4 in a Fatboy H404 anyone!?

 

[benjarvis]

Originally posted by nialloswald
RTV did one on a G55

Mike 'scary' Hoffman turned up at EARS in December with an estes Big Daddy, complete with wonky fins and launch lug (yes, lug!) big enough to fit a 'C' motor in, and a Pro38 H hanging out the back.

Contrary to the predictions of all assembled, it actually worked - no shred, no skywriting, and a chute!

It wasn't pretty, but it worked.

F101T was 24mm right - so you could get 4 in a Fatboy H404 anyone!?

Estes kit abuse is a classic sport, we should do it more often

You find me four F101T's and I'll build the Fat Boy

And yes, they're 24mm...

what about 7 of those 18mm full 'E's or were they low 'F's that AeroTech used to make?

If you stretched it a bit and took the bulkhead out of the base of the nose you could fit a 54/852 case in there

J460T?


Ben

 

[Westy]

The possibilities for the FatBoy kit are endless......I have my fingers crossed that it doesn't follow the same path as the Big Daddy "OOP" ! !

Westy

 

[Elapid]

has 2-24mm, 2-13mm, and 4-18mm in the booster, and up to 4-24mm in the sustainer.


did i mention that it's a 2-stage?

 

[nialloswald]

That looks cool...how're you doing the staging?

 

[Elapid]

here is the thread

https://www.rocketryforum.com/showthread.php?s=&threadid=12309&highlight=fat+boy+^2

in 3 flights, the staging has been 100% successful.

 

[nialloswald]

Nice....I thought of doing something similar. My thoughts were to set the booster up with 4x24mm MMTs, of which two would hold D12-0's and the other two some combination of D12-3 or -5's.

The D12-0's would each have a length of quickmatch running to the quickmatch (i love that stuff!) bundle for the 4x24mm sustainer. Of course the booster would be lit with QM too.

The idea I had for recovery was to set the booster up so that the -0 MMT's were extended to run through a coupler 'nose cone/interstage' which would separate from the sustainer body at deployment, the idea being to keep the parachute away from the staging gases

Dunno if that makes any sense, I ditched the idea and my 2-stage clustered design became less of a Fat Boy and more of a long skinny boy 7 out of 10 flights in primer, time for a decent paintjob - see attached photo. Time also to fly 2-stage again

 

[flyr98]

I'm doing the same with a Big Daddy kit and I am going to fly it on 3 G40's!