Centering Ring Placement


Gary Slater
 

Taking a pole.  
 
I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)
 
This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.
 
Do you like:
1: the forward ring in the most forward position at leading fin tip 
or
2: on top of the TTW fin tab? 
 
The other will of course, will be located behind the fin tab.
 
Thanks for your input.  


Mark Joseph
 

I say capture the fin tabs, so I would prefer the second one on top of the fin tab, if you don't have an option for 3.

Mark

________________________________________

From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Gary Slater <gws77@...>
Sent: Thursday, June 10, 2021 4:50 PM
To: cia-rocketry@groups.io
Subject: [cia-rocketry] Centering Ring Placement

Taking a pole.

I know what I want to do. This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying. (Chris will like that!)

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.

Do you like:
1: the forward ring in the most forward position at leading fin tip
or
2: on top of the TTW fin tab?

The other will of course, will be located behind the fin tab.

Thanks for your input.


Greg Montalvo
 

Yes, capture the fin tabs between the two centering rings.  It makes for a stronger system.  I like to build mine from the front back.  This allows me to get a solid glue connection between the centering rings and the fin tabs.

On Jun 10, 2021 4:50 PM, Gary Slater <gws77@...> wrote:
Taking a pole.  
 
I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)
 
This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.
 
Do you like:
1: the forward ring in the most forward position at leading fin tip 
or
2: on top of the TTW fin tab? 
 
The other will of course, will be located behind the fin tab.
 
Thanks for your input.  


Gary Slater
 

Thank you Mark.  
And I just noticed my misspelled word.  Poll, not pole.

On 06/10/2021 4:53 PM Mark Joseph <markjos@...> wrote:
 
 
I say capture the fin tabs, so I would prefer the second one on top of the fin tab, if you don't have an option for 3.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Gary Slater <gws77@...>
Sent: Thursday, June 10, 2021 4:50 PM
To: cia-rocketry@groups.io
Subject: [cia-rocketry] Centering Ring Placement

Taking a pole.

I know what I want to do. This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying. (Chris will like that!)

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.

Do you like:
1: the forward ring in the most forward position at leading fin tip
or
2: on top of the TTW fin tab?

The other will of course, will be located behind the fin tab.

Thanks for your input.


Kevin A
 

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin


On Thu, Jun 10, 2021, 4:50 PM Gary Slater <gws77@...> wrote:
Taking a pole.  
 
I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)
 
This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.
 
Do you like:
1: the forward ring in the most forward position at leading fin tip 
or
2: on top of the TTW fin tab? 
 
The other will of course, will be located behind the fin tab.
 
Thanks for your input.  


Christopher Deem
 

I agree with Mark. Capture the fin tabs.



Sent from my Galaxy


-------- Original message --------
From: Mark Joseph <markjos@...>
Date: 6/10/21 4:53 PM (GMT-06:00)
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

I say capture the fin tabs, so I would prefer the second one on top of the fin tab, if you don't have an option for 3.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Gary Slater <gws77@...>
Sent: Thursday, June 10, 2021 4:50 PM
To: cia-rocketry@groups.io
Subject: [cia-rocketry] Centering Ring Placement

Taking a pole.

I know what I want to do. This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying. (Chris will like that!)

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.

Do you like:
1: the forward ring in the most forward position at leading fin tip
or
2: on top of the TTW fin tab?

The other will of course, will be located behind the fin tab.

Thanks for your input.


Mark Joseph
 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________

From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin


On Thu, Jun 10, 2021, 4:50 PM Gary Slater <gws77@...<mailto:gws77@...>> wrote:
Taking a pole.

I know what I want to do. This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying. (Chris will like that!)

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.
I have only 2 centering rings. Adding a 3 ring is not an option.

Do you like:
1: the forward ring in the most forward position at leading fin tip
or
2: on top of the TTW fin tab?

The other will of course, will be located behind the fin tab.

Thanks for your input.


Greg Smith
 

Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Gary Slater
 

Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Kevin A
 

Is the limitation only having 2, or does something in the design prevent a 3rd?


On Thu, Jun 10, 2021, 6:11 PM Gary Slater <gws77@...> wrote:
Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Randy Milliken
 

Personally, I would cut out a 3 centering ring if the only reason to have only 2 is because you only have 2. :-) 

Randy

------ Original Message ------
From: "Gary Slater" <gws77@...>
Sent: 6/10/2021 7:10:55 PM
Subject: Re: [cia-rocketry] Centering Ring Placement

Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Gary Slater
 

The limitation is that I got only two with the kit. 

There are instances particularly in short, stubby high power rockets that recovery gear may have to be in the nose cone or somewhat wrapped around a motor that invades the airframe space. Just sayin. 

I prefer a centering ring at both ends of the fins if possible but I also realize the strength lies at the centering ring/fin tab interface. I often add that 3rd CR when I build a rocket with “short” fin tabs like the one in question because I want that extra little bit of airframe stiffness where the forward fin tip meets the tube. 

So my options are to make another,  buy another or do without.  This rocket airframe length and volume will accommodate the recovery even if I do add that forward ring. Even more so because the shoulder of the nose is open giving me an extra 3 1/2 inches of length/volume. 

For the record the kit in question is a Loc Minie Magg. I am removing the closed aft end of the nose. 

On Jun 10, 2021, at 6:19 PM, Kevin A <kauskings@...> wrote:


Is the limitation only having 2, or does something in the design prevent a 3rd?

On Thu, Jun 10, 2021, 6:11 PM Gary Slater <gws77@...> wrote:
Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Kevin A
 

The Minnie Magg kitshould most definitely include 3 rings... Mine should be done for GARLO.  I'd personally get a hold of LOC and ask them to send another.


On Thu, Jun 10, 2021, 6:42 PM Gary Slater <gws77@...> wrote:
The limitation is that I got only two with the kit. 

There are instances particularly in short, stubby high power rockets that recovery gear may have to be in the nose cone or somewhat wrapped around a motor that invades the airframe space. Just sayin. 

I prefer a centering ring at both ends of the fins if possible but I also realize the strength lies at the centering ring/fin tab interface. I often add that 3rd CR when I build a rocket with “short” fin tabs like the one in question because I want that extra little bit of airframe stiffness where the forward fin tip meets the tube. 

So my options are to make another,  buy another or do without.  This rocket airframe length and volume will accommodate the recovery even if I do add that forward ring. Even more so because the shoulder of the nose is open giving me an extra 3 1/2 inches of length/volume. 

For the record the kit in question is a Loc Minie Magg. I am removing the closed aft end of the nose. 

On Jun 10, 2021, at 6:19 PM, Kevin A <kauskings@...> wrote:


Is the limitation only having 2, or does something in the design prevent a 3rd?

On Thu, Jun 10, 2021, 6:11 PM Gary Slater <gws77@...> wrote:
Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


Gary Slater
 

I should. That kit has been laying around here a couple of years now. 

On Jun 10, 2021, at 6:51 PM, Kevin A <kauskings@...> wrote:


The Minnie Magg kitshould most definitely include 3 rings... Mine should be done for GARLO.  I'd personally get a hold of LOC and ask them to send another.

On Thu, Jun 10, 2021, 6:42 PM Gary Slater <gws77@...> wrote:
The limitation is that I got only two with the kit. 

There are instances particularly in short, stubby high power rockets that recovery gear may have to be in the nose cone or somewhat wrapped around a motor that invades the airframe space. Just sayin. 

I prefer a centering ring at both ends of the fins if possible but I also realize the strength lies at the centering ring/fin tab interface. I often add that 3rd CR when I build a rocket with “short” fin tabs like the one in question because I want that extra little bit of airframe stiffness where the forward fin tip meets the tube. 

So my options are to make another,  buy another or do without.  This rocket airframe length and volume will accommodate the recovery even if I do add that forward ring. Even more so because the shoulder of the nose is open giving me an extra 3 1/2 inches of length/volume. 

For the record the kit in question is a Loc Minie Magg. I am removing the closed aft end of the nose. 

On Jun 10, 2021, at 6:19 PM, Kevin A <kauskings@...> wrote:


Is the limitation only having 2, or does something in the design prevent a 3rd?

On Thu, Jun 10, 2021, 6:11 PM Gary Slater <gws77@...> wrote:
Let me add some information. 
The motor tube option is to accommodate up to a 38/720 case. So about 14 inches. 
What I want is all 3 CRs but I only have 2. 

On Jun 10, 2021, at 5:50 PM, Greg Smith <gregs@...> wrote:



Agree completely with Mark. A third, forward ring is useful because it provides a convenient anchor point for a U-bolt or other recovery attachment, and it makes construction easier because it holds the motor tube in good alignment while you work on the internal fin tabs and fillets. But its structural contribution is minor.

 

- GDS

 

 

 

From: cia-rocketry@groups.io [mailto:cia-rocketry@groups.io] On Behalf Of Mark Joseph
Sent: Thursday, June 10, 2021 5:45 PM
To: cia-rocketry@groups.io
Subject: Re: [cia-rocketry] Centering Ring Placement

 

Interesting points, Kevin.

One concern in not having a truly "forward" centering ring has to do with conveniently and securely anchoring the recovery harness. If you've got that worked out in some other way, then I wouldn't give this a second thought. My opinion is that supporting the forward end of the motor mount (or even motor mounts long enough for the range of intended motors) is a somewhat overrated concept. I think that the structural integrity gained by creating the mechanical "system" of airframe/fin tabs/centering rings/motor mount/epoxy is the bottom line.

Thanks for letting me ramble. Again.

Mark

________________________________________
From: cia-rocketry@groups.io <cia-rocketry@groups.io> on behalf of Kevin A <kauskings@...>
Sent: Thursday, June 10, 2021 5:22 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

Just my noob thoughts.

Cheers,
Kevin

._,_


steven dramstad
 

I know Mini Mags are short but I would want the forward most ring far enough forward that you don’t have a lot of body tube to pressurize for ejection. 38s don’t usually come with a lot of black powder. I would make a 3rd ring and position it as far forward as is practical.

Steve

 

 

Sent from Mail for Windows 10

 

From: Kevin A
Sent: Thursday, June 10, 2021 5:23 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

 

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

 

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

 

Just my noob thoughts.

 

Cheers,

Kevin

 

On Thu, Jun 10, 2021, 4:50 PM Gary Slater <gws77@...> wrote:

Taking a pole.  

 

I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)

 

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.

I have only 2 centering rings. Adding a 3 ring is not an option.

 

Do you like:

1: the forward ring in the most forward position at leading fin tip 

or

2: on top of the TTW fin tab? 

 

The other will of course, will be located behind the fin tab.

 

Thanks for your input.  

 


Gary Slater
 

Enough 4F isnt an issue for me, Steve.  

 My tools are not all out of storage or are still boxed up since my move. Making a CR is my problem. 

Costs more to ship one than the ring does I think. 

On Jun 10, 2021, at 7:43 PM, steven dramstad <sdramstad@...> wrote:



I know Mini Mags are short but I would want the forward most ring far enough forward that you don’t have a lot of body tube to pressurize for ejection. 38s don’t usually come with a lot of black powder. I would make a 3rd ring and position it as far forward as is practical.

Steve

 

 

Sent from Mail for Windows 10

 

From: Kevin A
Sent: Thursday, June 10, 2021 5:23 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

 

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

 

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

 

Just my noob thoughts.

 

Cheers,

Kevin

 

On Thu, Jun 10, 2021, 4:50 PM Gary Slater <gws77@...> wrote:

Taking a pole.  

 

I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)

 

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.

I have only 2 centering rings. Adding a 3 ring is not an option.

 

Do you like:

1: the forward ring in the most forward position at leading fin tip 

or

2: on top of the TTW fin tab? 

 

The other will of course, will be located behind the fin tab.

 

Thanks for your input.  

 


Kevin A
 

I would just contact LOC and tell them your situation.  I can't imagine they'd charge you.

Might even be worth asking if they'd send new fins.  The new design is much more robust than the old tab lock fin design.  (If your kit isn't the latest revision)

On Thu, Jun 10, 2021, 9:19 PM Gary Slater <gws77@...> wrote:
Enough 4F isnt an issue for me, Steve.  

 My tools are not all out of storage or are still boxed up since my move. Making a CR is my problem. 

Costs more to ship one than the ring does I think. 

On Jun 10, 2021, at 7:43 PM, steven dramstad <sdramstad@...> wrote:



I know Mini Mags are short but I would want the forward most ring far enough forward that you don’t have a lot of body tube to pressurize for ejection. 38s don’t usually come with a lot of black powder. I would make a 3rd ring and position it as far forward as is practical.

Steve

 

 

Sent from Mail for Windows 10

 

From: Kevin A
Sent: Thursday, June 10, 2021 5:23 PM
To: cia-rocketry@groups.io Group Moderators
Subject: Re: [cia-rocketry] Centering Ring Placement

 

I would think at the top of the TTW fin tab would give the best support... But how far past that point does the MMT extend?

 

If that ring is not at least slightly past the midpoint of the MMT, I'd be looking at other options... Perhaps some shims at the leading end of the MMT tube vs a full ring?

 

Just my noob thoughts.

 

Cheers,

Kevin

 

On Thu, Jun 10, 2021, 4:50 PM Gary Slater <gws77@...> wrote:

Taking a pole.  

 

I know what I want to do.  This is just for discussion, especially for the newer flyers who may be wanting to get into more mid-high power flying.  (Chris will like that!)

 

This rocket uses a Loc 5.5 in airframe with a 38 mm MMT and will fly H-J motors.

I have only 2 centering rings. Adding a 3 ring is not an option.

 

Do you like:

1: the forward ring in the most forward position at leading fin tip 

or

2: on top of the TTW fin tab? 

 

The other will of course, will be located behind the fin tab.

 

Thanks for your input.