LOC "AURA" motor mount question

LOC "AURA" motor mount question

Post by Rich » Mon, 12 May 1997 04:00:00



I PURCHASED A LOC / PRECISION "AURA" AND
DISCOVERED THAT MY AEROTECH RMS IS
EXPECTED TO STAY IN PLACE WITH MASKING TAPE!

DOES ANYONE MAKE A REAL MOTOR ADAPTER FOR THIS
ROCKET?

Regards;
Rich O.

"When at first you DO succeed, try hard to hide your astonishment !"

 
 
 

LOC "AURA" motor mount question

Post by Foxe » Tue, 13 May 1997 04:00:00


Quote:

>I PURCHASED A LOC / PRECISION "AURA" AND
>DISCOVERED THAT MY AEROTECH RMS IS
>EXPECTED TO STAY IN PLACE WITH MASKING TAPE!

>DOES ANYONE MAKE A REAL MOTOR ADAPTER FOR THIS
>ROCKET?

>Regards;
>Rich O.

>"When at first you DO succeed, try hard to hide your astonishment !"

Please do not type in all CAPS!, ok, as far as motor mount / retention
goes that seems to be the norm for most HPR rockets.  One other idea
out of a few options is to install blind (t-nuts) nuts (4-40 or 6-32)
in the aft centerig ring, 180 deg apart, and midway between the MT and
BT  while making the rocket, and using screws and small metal clips or
tabs, with a hole in them, to accept the screw, and***these into
the blindnuts, and the other end goes against the aft nozzle end of
the motor, or use a piece of aircraft plywood or aluminum, cut a hole
in the center to pass over nozzle of motor, then drill 2 holes in this
piece inline with the blind nuts, anbd use this to anchor the motor in
place.

If using a RMS type motor no forward thrust ring is needed, but on a
SU one needs to make a thrust ring out of 1/4 or 1/2" tape to prevent
forward motor movement.

Tape seems to be the NORM and accepted way for even top of the line
kits.  I myself as well as many others prefer positive motor
retention, as described above.


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sender agrees to pay a $100 flat fee to the recipient for proofreading
services.  Take the www out of address to send email.

 
 
 

LOC "AURA" motor mount question

Post by Kevin Henegha » Tue, 13 May 1997 04:00:00


If you still can,

        Built the kit with the motor tube sticking out the aft end of the rocket
about 1/8 to 1/4 inch. This gives you plenty of room to tape the RMS
hardware
to the motor mount tube.

        I have not had a problem with losing hardware in this rocket using tape.

        I have had problems getting my motor hardware back out of the rocket,
        once it has flown.

        Kevin Heneghan



Quote:

> >I PURCHASED A LOC / PRECISION "AURA" AND
> >DISCOVERED THAT MY AEROTECH RMS IS
> >EXPECTED TO STAY IN PLACE WITH MASKING TAPE!

> >DOES ANYONE MAKE A REAL MOTOR ADAPTER FOR THIS
> >ROCKET?

> >Regards;
> >Rich O.

> >"When at first you DO succeed, try hard to hide your astonishment !"

> Please do not type in all CAPS!, ok, as far as motor mount / retention
> goes that seems to be the norm for most HPR rockets.  One other idea
> out of a few options is to install blind (t-nuts) nuts (4-40 or 6-32)
> in the aft centerig ring, 180 deg apart, and midway between the MT and
> BT  while making the rocket, and using screws and small metal clips or
> tabs, with a hole in them, to accept the screw, and***these into
> the blindnuts, and the other end goes against the aft nozzle end of
> the motor, or use a piece of aircraft plywood or aluminum, cut a hole
> in the center to pass over nozzle of motor, then drill 2 holes in this
> piece inline with the blind nuts, anbd use this to anchor the motor in
> place.

> If using a RMS type motor no forward thrust ring is needed, but on a
> SU one needs to make a thrust ring out of 1/4 or 1/2" tape to prevent
> forward motor movement.

> Tape seems to be the NORM and accepted way for even top of the line
> kits.  I myself as well as many others prefer positive motor
> retention, as described above.


> By sending unsolicited commercially-oriented e-mail to this address, the
> sender agrees to pay a $100 flat fee to the recipient for proofreading
> services.  Take the www out of address to send email.

 
 
 

LOC "AURA" motor mount question

Post by Larry W. Hardi » Tue, 13 May 1997 04:00:00


I "engineered" a positive retention system for the Aura.  The airframe
tube is not large enough to use the clips with blindnuts in the aft
centering ring that seems to be popular with larger rockets.  I got
an Estes E size retaining clip and straightened the top bend so it
would not penetrate the motor tube.  I epoxied that to the side of the
motor tube, installed the centering rings, and wrapped the clip with
glass cloth & epoxy between the centering rings.  You need to let the
clip project a bit past the end of the rocket to get enough clearance
to remove the engine.  I used an adapter from an Aerotech kit to form
an engine block spaced to suit the RMS 29/40-120 casing.  That way, I
can use my Aerotech adapters to fit the 24mm casing as well.  Also,
I installed the LOC modular baffle unit to eliminate the need for
wadding.  The rocket is being painted now, so I can't give a flight
report.  The engine installation is shifted back 1/4" which means the
CG is back a bit and I'll check stability before flying.

Larry

 
 
 

LOC "AURA" motor mount question

Post by Bob Kapl » Thu, 15 May 1997 04:00:00



Quote:
> I installed the LOC modular baffle unit to eliminate the need for
> wadding.  The rocket is being painted now, so I can't give a flight

Be very careful with baffles and reloads. The baffle increases the back
pressure to the motor, making positive motor retention an even greater
issue. The one time I used a LOC baffle was in an Ultimate, where there was
no room for the Kaplow Klip. Even with threaded inserts between the motor
mounts, I blew the bolts and the casing out. Luckily a kid found the casing
for me. [That's why I put those name and address stickers on everything.
Just got another call this weekend from someone who found my lost Maniac/F7
flight from 2 weeks earlier.]

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"

 
 
 

LOC "AURA" motor mount question

Post by Bob Kapl » Thu, 15 May 1997 04:00:00



Quote:
> I "engineered" a positive retention system for the Aura.  The airframe
> tube is not large enough to use the clips with blindnuts in the aft
> centering ring that seems to be popular with larger rockets.  I got

You'd be surprised what you can do with really tiny hardware. I've found
blind nuts down to 2-56, and when necessary have filed down some of the
flange until they really do look like "T" nuts. If you don't like that, use
the threaded brass inserts. Again, I've seen these down to at least 2-56.

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"

 
 
 

LOC "AURA" motor mount question

Post by Rich » Thu, 15 May 1997 04:00:00


Quote:
>You'd be surprised what you can do with really tiny hardware. I've found
>blind nuts...

OK, what are blind nuts?  I went to Home Depot and they thought I was nuts!

Regards;
Rich O.

"When at first you DO succeed, try hard to hide your astonishment !"

 
 
 

LOC "AURA" motor mount question

Post by Bob Kapl » Thu, 15 May 1997 04:00:00


Quote:

>>You'd be surprised what you can do with really tiny hardware. I've found
>>blind nuts...

> OK, what are blind nuts?  I went to Home Depot and they thought I was nuts!

Well, they may or may not have been correct :-) but they should have known
what they were.

Blind nuts are also called T nuts. The best I can describe them without
resorting to bas ascii art is to say they are washers with a threaded stem
attached. The flat part of the washer either has holes for nails, or spurs
bent out of them to attach the nut to a hole drilled in the centering ring.
Be sure to put the large flat side on the back of the centering ring so that
they can't pull out.

For a complete picture of how to use blind nuts in the "Kaplow Klip" motor
retention system, see the October 1996 issue of Sport Rocketry.

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"

 
 
 

LOC "AURA" motor mount question

Post by Ted H. Apk » Thu, 15 May 1997 04:00:00


Quote:

> >You'd be surprised what you can do with really tiny hardware. I've found
> >blind nuts...

> OK, what are blind nuts?  I went to Home Depot and they thought I was nuts!

> Regards;
> Rich O.

> "When at first you DO succeed, try hard to hide your astonishment !"

Rich,
        They've got them at Home Depot.  Maybe not down to 5/56, but
small enough for most of my stuff.  Look for those yellow drawers of
special hardware.  Then look for T-Nuts.  Sometimes called blind nuts.
Then look for the person who manages the department and suggest that
they might want to look for another sales person!  You can pick up
the small ones and some nifty allen head screws from most hobby
stores like Zeppelin.

Ted

 
 
 

LOC "AURA" motor mount question

Post by Rich » Fri, 16 May 1997 04:00:00




Quote:
>> OK, what are blind nuts?  I went to Home Depot and they thought I was
nuts!

>Well, they may or may not have been correct :-) but they should have known
>what they were.

>Blind nuts are also called T nuts...

I bought T-nuts at home depot, thinking they would do the job.
Last night I went to the local hardware store and the clerk
wasn't sure either, so he called someone for the information.

Who was his expert?  

The local hobby shop that I normally haunt!

I should have tried them first!

Regards;
Rich O.

"When at first you DO succeed, try hard to hide your astonishment !"

 
 
 

LOC "AURA" motor mount question

Post by Bill Sinkin » Sat, 17 May 1997 04:00:00


<snip discussion of t-nuts>

I forget who started this thread, but the original question was
about how to fit an Aura with positive retention.  I don't think
t-nuts are the answer: this is a 38mm rocket with a 29mm mount, so
after accounting for tube thickness, there aren't many mms left
for hardware.  Moreover, the centering rings are thick, heavy
cardboard rather than plywood.  On my Aura I took a regular Estes
motor hook and chopped off the front end, so it doesn't pierce the
motor tube.  I epoxied it into place under the aft centering ring
(had to carve a channel on the inside surface of the ring because
the fit was very snug).  I use a tape thrust ring on the motor.  I've
only flown it once so far, on an Econojet F20-7 - very high flight,
and the retention system worked perfectly.

Bill Sinkins  NAR 70029