clustering fat boy????

[lipp]

I was just wandering if anyone knows if FlisKits makes a clustered engine mount that will fit in Estes Fat Boy????

 

[slim_t]

Fliskits recently introduced some new cluster mounts based on the BT80 which is what the Fat Boy BT is, but they aren't available yet. I just checked the site. Maybe Jim will reply soon and let us know when they'll be available.

Click here:

https://www.rocketryforum.com/showthread.php?s=&threadid=11054&highlight=fliskits+cluster+bt80

Tim

 

[joepolicy]

The Fatboy boy uses a BT-80 tube. Fliskits currently only offers clusters for up to BT-70, but according to the website, BT-80 cluster motor mounts will be offered in the future.

Thrustline carries motor mounts for BT-80, here are some links:

4 Engine Cluster (4 X 24mm) MMT kit
https://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2567&item=5911411652&rd=1&ssPageName=WD1V

3 Engine (2 X 18, 1 X 24mm) MMT kit
https://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2567&item=5920619392&rd=1&ssPageName=WD1V

Thrustline also sell rings so you can build your own MMT. Go to Ebay and do a search for BT80

And, BalsaMachining
https://www.balsamachining.com/

carries a variety of cluster centering rings for T80 tubes as well as the motor tubes themselves so you can BYO. I am sure there are others out there that also carry what you need.

 

[lipp]

how much weight should I put in the nose????

 

[rocketsonly]

Originally posted by lipp
how much weight should I put in the nose????

I would first find the CG without the cluster, but everything stock (just don't glue to stuff in). Then mark the CG. Then put in the cluster rings and motor tubes. Then add weight to the nose till the CG is the same.

Hope that helps.

 

[joepolicy]

For my 4 x 24 Fatboy (1 of 5 Fatboy cluster configurations I have), I used 12 oz in the nose cone. With the 4 motors installed, the static margin is right at 1.05. The Fatboy makes a great cluster and is fun to fly!

 

[flying_silverad]

Originally posted by joepolicy
The Fatboy boy uses a BT-80 tube. Fliskits currently only offers clusters for up to BT-70, but according to the website, BT-80 cluster motor mounts will be offered in the future.

Thrustline carries motor mounts for BT-80, here are some links:

4 Engine Cluster (4 X 24mm) MMT kit
https://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2567&item=5911411652&rd=1&ssPageName=WD1V

3 Engine (2 X 18, 1 X 24mm) MMT kit
https://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2567&item=5920619392&rd=1&ssPageName=WD1V

Thrustline also sell rings so you can build your own MMT. Go to Ebay and do a search for BT80

And, BalsaMachining
https://www.balsamachining.com/

carries a variety of cluster centering rings for T80 tubes as well as the motor tubes themselves so you can BYO. I am sure there are others out there that also carry what you need.

Thanks Joe! You took the words right out of my mouth!

 

[lipp]

thanks for all the help

 

[JStarStar]

Originally posted by lipp
how much weight should I put in the nose????

You'd want to RockSim it... the FatBoy is a pretty short, stubby design to start out with. Installing a cluster mount and motors in the tail end is gonna pull that CG back quite a bit.

Just off the top-of-the-head, I'd guess you'd have to put a couple ounces at least.

 

[flying_silverad]

I simm'd it out to 3- 3.5 ounces for a marginally stable rocket with 3 D12's. It was almost a full caliper between CG and CP. That would work.

4 Motors would be closer to 4 oz's I suspect.

 

[Rocketjunkie]

My 12 x 13 mm Fat Boy has 100g nose weight. this is enough for stability with 12 C20's installed. Here it is on A3-4's.

https://www.tripolisc.org/modules/x...oops_imageid=713&set_albumName=album27&id=aaa
https://www.tripolisc.org/modules/x...oops_imageid=805&set_albumName=album27&id=abu

 

[gerbs4me]

cool pics rocketjunkie