From: barrett@add.itg.ti.com
Newsgroups: rec.models.rockets
Subject: Re: Aereoux
Date: 6 Jan 93 21:25:39 GMT
Organization: Texas Instruments Incorporated, Austin
NNTP-Posting-Host: powder.add.itg.ti.com

Thomas E. Smith writes:

>>  I built an Aereoux rocket a little while ago, and had a couple of good
>>launches out of it.  The rocket is supposed to get up to about 3000 ft
>>which is just out of visual range for me, but I could still see the
>>parachute deploy.  Well, the last time I flew it, I lost sight of it and
>>never saw the chute, or the rocket again.  For all I know it went into
>>orbit :)  (I launched it into the wind, but without the chute it didn't
>>fall any where near me.)  The rocket uses the coiled metal (what's the
>>proper name for this?)  to cool the exhaust that will pop the chute.  I
>>think that it may have blocked the air from going through somehow.
>>
>>  Since I am re-building the Aereoux I was wondering if any one has had
>>the same trouble with the rocket or the coiled metal.

  Tom, I have built a few Aerotech models in my time.  I posted a
"construction tips" article a while back.  It might be good to repost it
again sine it looks like other folks are starting to re-discover some of
the problems with them.

  BTW:  The plugged baffle is a notorious problem, good guess (although
without a proper post-mortum, just a conjecture).

=============================================================

                Aerotech Construction Tips


  I first thought that the overall design of the kits were quite good,
however, I did have some problems that I figured out fixes for.

  - The internal thrust ring is a real pain.  The spacers tend to get
welded to their cheap motor mount tubes (Buzz, note I didn't say engine
;-)).  Don't use it.  Instead, use an external thrust ring at the base
of the engine.  I use 1/2" masking tape or I epoxy a 3/8" piece of MMT
to the end of the engine.  This allows for longer engines anyway (e.g.
H70, H100, G42, etc).

  - The motor retention "hook" gets the big heave ho.  I had a few
motors come out; even a re-load :-(.  I extent the MMT 3/4" behind the
aft bulkhead and then use tape (strapping tape if a reloadable motor is
involved) to keep the engine from coming out at ejection.  This means
that you will have to move the Fin Lock rings forward a corresponding
distance.

  - The Aerotech MMTs are really poor.  After a few flights, they tend
to burn up!  I use Phenalic(sp?)  MMT on all my rockets now.
Unfortunately it is real hard to get the Fin Lock rings to fit a 29mm
Phenalic tube without lots of sanding.  I would paint the outside of the
MMT with some finish coat epoxy (after you glue the Fin lock rings into
position) in order to give it some added durability.

  - I would also coat the aft end of the MMT with Epoxy so that it is
reenforced to stand up to many launches/motor insertions.  Even a thin
coat on the inside would help. You will have to sand after it dries
before a motor will fit.

  - The baffle system needs to be inspected before EVERY launch.  It
tends to get clogged up and will eventually cause the ejection to vent
side ways through the side of the rocket (which then becomes a lawn
dart!).  Take a 1/4 wooden dowel and drill a hole in the end and epoxy a
1" pin or small nail to the end.  Poke holes in the wire mesh to keep it
porous.  You will have to replace the wire mesh with a "chore boy" after
6-10 launches.  Unfortunately the old mesh tends to weld itself to the
plastic piece at the top so this is a pain.  You really can't use
wadding because the shock cord is attached to the forward bulkhead
(unless you move the attachment point ala LOC).

  - Don't tie the shock cords to either the nosecone/payload section or
the parachute; use small quick links instead.  This makes for easier
transportation and more flexible interchange of parts.

  - Use Epoxy on everything!  CA should only be used to tack a piece in
place (the spray CA accelerators work GREAT for this).

That should do it.  Aerotech models are a good first step from the Estes
arena, however, they really can't be considered a durable HPR vehicle.

Stu Barrett  barrett@add.itg.ti.com
TRA#1277  NAR#4341
Newsgroups: rec.models.rockets