54mm fin cans

Performance nut

Well-Known Member
Joined
Nov 30, 2012
Messages
224
Reaction score
4
Hey all. I came across 6' of Hawk Mountain 54mm fiberglass tubing I bought awhile back. Also found an Acme fincan that Giant Leap lightened up. Just need a good nosecone and a motor retainer to make an easy semi-bullet proof minimum diameter rocket project. Only thing I have no idea how well the Acme fincan will hold up to heat once you start getting into crazy fast motors (Cesaroni K1440). I have an image of a lump of plastic at the end of a fiberglass tube like a big lollipop when I eventually find it.

Sim I ran last night says it can get Mach 2 with the right motors and trimming the length down. I have no idea how accurate that is but seems like an easy project to find out. Anyone know how well the Acme fincans hold up? Been eyeballin' the Max Q wares for awhile too. Seems that would be better suited for things up to an L2300 (don't blink). Any recommendations based on usage? I almost want to do a fincan performance test to see how well they do against each other.
 

mpitfield

Well-Known Member
TRF Supporter
Joined
Jul 6, 2013
Messages
4,902
Reaction score
446
Location
Toronto, Ontario
I have one of those fincans but I opted not to use it on the first MD build I contemplated. This was more for philosophical reasons for my evolving definition of a MD.

Staying true to my definition I didn't feel that the raised part met my criteria. On that topic I believe this may also throw off your sim unless you account for it in the design.
 

lawndartman

Well-Known Member
Joined
Mar 11, 2011
Messages
632
Reaction score
29
I have flown the 54 fin cans with about every CTI 54 there is. I have used them for years. NEVER had a problem. I put the retainer inside the can, just a little time with a Drummil will do the job. I have never gone Mach 2, but that may be another can of worms...but heat melting, no way. Tim Thomas L3
 

Dugway

Well-Known Member
Joined
Jan 23, 2015
Messages
287
Reaction score
197
Location
Draper, UT
I've flow the crap out of half-a-dozen Acme fin cans, both 38mm and 54mm, but never in a minimum diameter rocket. They seem pretty bullet proof. If you're worried about high speed melting these, I would be way more worried about melting the nose cone. The heat from the motor isn't going to touch these, any more that a motor would melt a fiberglass motor tube.
 

lowga

A.K.A. 'Mr. HoJo'
TRF Supporter
Joined
Dec 4, 2016
Messages
593
Reaction score
203
Location
Birmingham, AL
I've only flown my Acme 54mm fin can a few times, but it's nearly indestructible. I had concerns about heating from both the motors and mach speeds, so I opted to use JB Weld to attach the fin can to the fiberglass air frame. Seems to work great, and super-strong.
 

blackjack2564

Crazy Jim's Gone Banana's
Joined
Jan 17, 2009
Messages
9,167
Reaction score
1,393
Location
Savannah Ga
Acme fin cans are made of Dupont Delrin.
Tig is 190 C or 378 F

You have to get that hot for extended period of time to have enough heat to deform the fincan.
That's a lot of heat soak.

Thickness of fins is at disadvantage compared to Binder Max-Q fincan.

If you have the Acme version with Cut-outs big 'O's you should fill them and taper/bevel the front lip/joint to airframe for better laminar flow.

If you are just building a dumb minimum for fun....Acme is OK.
If you are going for max speed/altitude use another design.
 
Top