Aero Pack tailcones

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Well-Known Member
Jan 26, 2009
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Anyone with experience using Aero Pack tailcones?
I am doing some dry fitting for my next build. A 4" rocket with a 3" hole.
I have used lots of Aero Pack's in the past but this will be my first build using a tailcone.
My question is will I have any problems using this tailcone with 54mm motors using the Aero Pack 54mm to 75mm adapter?
The instructions for the adapter show the tapered section of the aft adapter ring facing down.
When I dry fit it in this position I do not like what I see.
When I flip the aft adapter 180 degrees ie. the tapered section up things look better.
Just doing my home work before I start the build.
Any helpfull hints on using Aero Pack tailcones will be appreciated.
L. T.

I had the same question when I built my Extreme Wildman so I emailed Aero Pack and here is there response:
(Sent in on their website)
Comments: I have the 75mm motor mount to 3.9" airframe tail cone retainer and have misplaced the instructions. How far from the end of the airframe should the motor mount protrude. Thanks, Eric Martin

(Aero Pack Reply)
Hi Eric,
For the TRA7539 tailcones the distance is 1.060 inches from end of airframe to end of motor tube.

If you have a fax I can fax the instructions. Otherwise I can scan them and attach to an email. Let me know.
Aero Pack

(My Reply)
Thanks for the quick reply. I think I'll be ok w/o the instructions. I do have one more question for clarification though. For the 75mm-54mm adapter and use with Aerotech motors the assembly should be after the motor is assembled first slide the thrust ring adapter on then snug the collar onto the motor, then place the spacer that came with the tailcone in the retainer body, then the motor with adapter, then the adapter spacer then the tailcone, is this correct?

(Aero Pack Reply)
Did you order the A5475 adapter at the same time you ordered the TRA7539 tailcone? If so you should have received a TRS54 (54mm tailcone spacer). When using an adapter in a tailcone retainer you use a 54mm spacer instead of the 75mm spacer, which are not required with standard motor retainers. So when you assemble the adapter onto the AeroTech motor you first slide the 54mm spacer ring (TRS54) onto the motor and down to the aft closure, followed by the thrust ring adapter down to the spacer that is against the aft closure. Then snug the centering ring onto the motor (at least 2 inches down from the front end of the motor). Then slide the motor/adapter assembly into the tailcone retainer body add the stepped spacer and screw on the cone.

The TRA7539 tailcone retainer assembly comes with a TRS75 spacer that is only used when you fly 75mm AeroTech or equivalent motors. But when flying 54mm AeroTech or equiv motors in the TRA7539 tailcone with an A5475 adapter the TRS54 spacer is used as described above. Please confirm you have a TRS54 spacer ring. If not I will mail one to you.

(My Reply)
I just got the regular adapter but I already use the TRA5430 on another rocket so I already have a spacer.

Thanks for the help. That is why I had the original question. Thing were not working the way I thought they should.

I hope this helps. By the way, next years launch schedule is out. I wonder if Sweaty Balls II is going to live up to it's name again?


Last edited:
Gary and Eric
Thanks for the info.
Looks like I need to get a TRS54 (54mm tailcone spacer).
The 75mm spacer measures .304" tall.
Thinking the 54mm spacer will be about 1/16" less.
What rocket is the tailcone going on?
Extreme WildMan of course.
Not sure if I will make Sweaty Balls II but plan on making Airfest.
The 3" Wildman drag race at MWP this year was cool.
13 or so Wildmen on L motors. Most were on the CTI L935.
Look to be my first mach+ flight.
The Arts II had it at 1191.61 ft/s.
L. T.