[roc-chat] Re: Aerotech Motor Design Question
- From: John Coker <john@xxxxxxxx>
- To: roc-chat@xxxxxxxxxxxxx
- Date: Tue, 27 Nov 2012 09:25:14 -0800
Yep, there are twelve in the flange and I'll be using at least six in the
future; probably all dozen. :)
It does make me wonder about the cheap steel used in standard T-nuts as
well. I'll look into using stronger steel in future, since it doesn't seem
like the threads should strip out so easily.
John
On Tue, Nov 27, 2012 at 9:18 AM, Jack Garibaldi <jackgaribaldi@xxxxxxx>wrote:
> John****
>
> ** **
>
> An old pro like yourself only used 4 screws when the
> Aeropack Flange has about 8 to 12 on there, it looks like you got lucky and
> kept the case until the end.****
>
> ** **
>
> Jack G****
>
> ** **
>
> *From:* roc-chat-bounce@xxxxxxxxxxxxx [mailto:
> roc-chat-bounce@xxxxxxxxxxxxx] *On Behalf Of *John Coker
> *Sent:* Tuesday, November 27, 2012 9:13 AM
>
> *To:* roc-chat@xxxxxxxxxxxxx
> *Subject:* [roc-chat] Re: Aerotech Motor Design Question****
>
> ** **
>
> Sometimes even the T-nuts aren't enough. There is a *lot* of force
> generated by the weight of a large motor case, even when empty. I used four
> #6 T-nuts through the aft C.R. to hold on a 98mm Aero-Pack retainer and the
> screws pulled right out of the T-nuts!****
>
> ** **
>
> http://jcrocket.com/arliss2008.shtml#mavericks2008****
>
> ** **
>
> John****
>
> On Tue, Nov 27, 2012 at 9:00 AM, Jack Garibaldi <jackgaribaldi@xxxxxxx>
> wrote:****
>
> Chris****
>
> ****
>
> The top one is under Madcow componants on my site and the
> screws are barrel screws so you just screw them into your aft ring then the
> threaded screw will screw into those, these type retainers are for rockets
> that are already built and done. On future rockets you need to think ahead
> and use Aeropack but you have to leave your motor tube extended out past
> your aft ring when you build up to 1/2” then JB weld the Aeropack on until
> you get to 54, 75 and 98mm then you go back to flush tube with aft closure
> because they have flanges on them for bolting on. There are glue on
> Aeropacs in the 54mm but when you start doing 75mm and 98mm I don’t
> believe in glueing on my motor retention with the powerful motors on the
> market today, just a extra precaution that I do.****
>
> ****
>
> Jack G****
>
> ****
>
> *From:* roc-chat-bounce@xxxxxxxxxxxxx [mailto:
> roc-chat-bounce@xxxxxxxxxxxxx] *On Behalf Of *Chris Coffee
> *Sent:* Monday, November 26, 2012 11:43 PM****
>
>
> *To:* roc-chat@xxxxxxxxxxxxx
> *Subject:* [roc-chat] Re: Aerotech Motor Design Question****
>
> ****
>
> Hey Jack,****
>
> ****
>
> What is the one in the top picture that looks like a exhaust gasket? I
> tried enlarging the picture but it becomes unreadable. I like the idea of
> the little clips, but my aft ring is already glued in place and I am not
> sure how I would get the female part of the screw set on the inside of the
> ring.****
>
> ****
>
> *From:* Jack Garibaldi <jackgaribaldi@xxxxxxx> ****
>
> *Sent:* Monday, November 26, 2012 6:22 PM****
>
> *To:* roc-chat@xxxxxxxxxxxxx ****
>
> *Subject:* [roc-chat] Re: Aerotech Motor Design Question****
>
> ****
>
> If you have room on your aft ring you could use two screws and two washers
> or these type motor retainers****
>
> ****
>
> [image: Motor Retainer 29mm]****
>
> ****
>
> [image: Z Clip Style Motor Retainer Set]****
>
> ****
>
> ****
>
> Jack G****
>
> ****
>
> *From:* roc-chat-bounce@xxxxxxxxxxxxx [
> mailto:roc-chat-bounce@xxxxxxxxxxxxx <roc-chat-bounce@xxxxxxxxxxxxx>] *On
> Behalf Of *Chris Coffee
> *Sent:* Monday, November 26, 2012 6:03 PM
> *To:* roc-chat@xxxxxxxxxxxxx
> *Subject:* [roc-chat] Re: Aerotech Motor Design Question****
>
> ****
>
> “Remember, friends don't let friends friction fit.”****
>
> ****
>
> On that note, both rockets that we have use friction fit for the motors.
> Now that the rocket is assembled, is there a way to incorporate a motor
> retention device into them? They both have the 29mm motor mounts. I am
> wanting use my RMS but since the rockets only use friction to retain the
> motor, I am worried about losing a $65 motor casing. Any suggestions.****
>
> ****
>
> Chris ****
>
> ****
>
> *From:* Lakestake Rocketry <lakestake@xxxxxxxxx> ****
>
> *Sent:* Monday, November 26, 2012 5:39 PM****
>
> *To:* roc-chat@xxxxxxxxxxxxx ****
>
> *Subject:* [roc-chat] Re: Aerotech Motor Design Question****
>
> ****
>
> Cool, another "Kevlar vs. Nylon" moment!****
>
> I have never lost a motor with positive retention. It comes down to a
> safety issue: if you kick the motor and don't deploy your recovery the
> rocket still comes back to earth.****
>
> Remember, friends don't let friends friction fit.****
>
> Matt****
>
> On Nov 24, 2012 10:41 PM, "David Erbas-White" <derbas@xxxxxxxxxxxxxxxx>
> wrote:****
>
> On 11/24/2012 10:10 PM, brian.morilak@xxxxxxxxx wrote:
>
> ...and as a follow on, now that I think about it, I've had a number of
> Aerotech engine hooks that didn't do a very good job or retaining the
> motor, and have kicked both single-use and reloadable motors. Thus, I now
> ALWAYS put a couple of wraps of tape around the aft end of a reloadable...
>
> David Erbas-White****
>
> On topic question:****
>
> Is it sufficient to use friction (masking tape) on a 24mm F/G motor for
> "negative" (ejection charge) retention? Or is an engine hook or end
> cap-type retainer an absolute must?
>
> On Nov 24, 2012, at 9:05 PM, David Erbas-White <derbas@xxxxxxxxxxxxxxxx>
> wrote:****
>
> On 11/24/2012 7:08 PM, Chris Coffee wrote:
>
> Older Aerotech motors were smooth. Then, for a while, they sold them with
> a cardboard ring that you could epoxy to the aft end of the motor to act as
> a stop. For the past few years, all Aerotech E/F/G motors (at least, that
> I am aware of) have the ring at the back molded into the case.
>
> I have found that (if you're using the Estes Pro Series II rockets - not
> motors) that you have to remove the label from the motor or they simply
> won't fit. The RMS motors (reloadables), however, do fit just fine.
>
> David Erbas-White****
>
> We are looking to buy more motors for our rockets. We need F & G size
> motors. The motors we just used were the Estes Pro Series II Single-Use
> motors. Neither of our rockets have a motor retainer, so my question is; do
> the Aerotech motors also have that protruding edge that stops the motor
> from going all the way up into the motor mount tube like the Estes does?
> Although the Estes worked fine, I am not real happy about having to buy
> igniters for each motor (especially if the just pop like one of ours did)
> when Aerotech supplies an igniter with their motors. Thanks.****
>
> ****
>
> Christopher L. Coffee****
>
> ****
>
> ****
>
> ** **
>
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