[sugpro] Re: Hello Sugpro
- From: "Michael Monteith" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "michael_r_monteith@xxxxxxxxx" for DMARC)
- To: sugpro@xxxxxxxxxxxxx
- Date: Tue, 10 Feb 2015 16:49:20 -0800
Andrej,
I thought I had read somewhere that there is a way to separate out
the anti-caking part. Might of course be in one of my books that's packed
for the moved and won't be here until like the first week of March. Uggh
But maybe someone here has surely been through that feat before.
Michael
--------------------------------------------
On Tue, 2/10/15, Andrej Vrbec <dmarc-noreply@xxxxxxxxxxxxx> wrote:
Subject: [sugpro] Re: Hello Sugpro
To: "sugpro@xxxxxxxxxxxxx" <sugpro@xxxxxxxxxxxxx>
Date: Tuesday, February 10, 2015, 4:30 PM
Ah, OK
that makes it clearer. I thought that you have a 70cm BRB
GPS version.No, I
don't use any clamping. I know that clamping should
improve density but I haven't yet come to try this. I
typically get grains to about 97-97,5% of ideal density.
I did
quite some experimentation with different grades of
potassium nitrate. My goal was to develop a mixing and
casting technique that would allow me to use a fertilizer
grade potassium nitrate which is very cheap and readily
available. I've tried many different grades, particle
sizes, pH values, defoamers, surfactants, vacuum
degasing, you name it I've done it. In the end I just
couldn't get the same high density propellant as I get
when I use a food grade potassium nitrate without anticaking
agent. I've read that a lot of people use fertilizer
grade KN with good success but it wasn't working for me.
Surfactans and defoamers helped to some degree but still
the density was lower than with a food grade KN. It seems
that anticaking agents used in this potassium nitrate
fertilizers have a significant efect on wetting abilities of
molten dextrose. as they make the KN particle surface more
hydrofobic. All these problems went away when I switched
back to a potassium nitrate without anticaking agent, which
is twice the price of fertilizer grade, but gives very
good results. So far I
didn't have any problems with disbonding even in large
grains. The material I use for the inhibitor is not a
paper, but a gasket material called Tesnit BA-202, which is
made of organic fibers and nitrile rubber. I cut the
material to correct size to fit snugly in the steel tubular
holder which is then heated in an oven to 150°C as well as
base and a coring rod. Just before pouring, the mould is
pulled from the oven and the propellant is cast. Here is the
link to this material website: http://donit.eu/material/ba-202/ I
use 0,5mm thickness and the factory that makes it is
conveniently located just a few kilometers from my home
:)
Andrej
From: Richard Nakka
<richard.rocketry@xxxxxxxxx>
To:
sugpro@xxxxxxxxxxxxx
Sent: Tuesday, February
10, 2015 8:55 PM
Subject: [sugpro] Re:
Hello Sugpro
Andrej,
Thanks for the info. I
actually bought the new BRB900 unit, which
comes with a simple GPS receiver. Great thing
about this unit is that
no amateur radio
licence is required.
To
keep this post on-topic, here's a question about your
propellant
grains (beauties, by the way). Do
you cure the KNDX under pressure or
clamping? To prevent disbonding. I've
temporarily migrated to KNSB to
get good
bonding (I use clamping pressure), but would like to get
back
to using KNDX...to hopefully get those
nice flat thrust curves that
your motors
exhibit :-)
Richard
On Tue, Feb
10, 2015 at 1:06 PM, Andrej Vrbec
<dmarc-noreply@xxxxxxxxxxxxx>
wrote:
> Hi Richard
>
> It's nice to hear
from you again. You are right, the propellant is plain
> KNDX. I've also experimented with
other sugars (sorbitol, erythritol and
>
mannitol) but in the end I decided in favor of dextrose.
> Bigredbee GPS was a real game changer at
least for me as I don't have large
>
open spaces to fly from. I fly from a small clearing in the
middle of the
> dense forest and so far I
haven't lost a rocket yet. BRB GPS is very easy to
> set up. First you must download a
configuration software from BRB website.
> When you connect the GPS to the computer
you can make settings like how
> often do
you want it to report location and altitude, your call sign,
output
> power, etc. On the ground you
will need some kind of radio setup that can
> decode incoming APRS data packets sent
from BRB GPS. There are a lot of
>
options but mostly it comes down to how much are you willing
to spend. Based
> on my experience I
would say that the best option for rocket use on the
> field would be an all-in-one radio such as
a Kenwood TH-D72 or a Yaesu
> VX-8GR
(recently discontinued) or Yaesu FT1DR. These radios are
pricey but
> very easy to carry around
when you are chasing you rocket as you don't have
> to have several pieces connected with
cables as would be the case with an
>
ordinary radio connected to a TNC (terminal node controler
such as Byonics
> TinyTrak4) and a
separate battery. When the radio receives the data packet
> from BRB GPS it decodes it and displays a
current altitude, latitude and
>
longitude. When the rocket lands you take the last known
coordinates and
> punch them into a
handheld GPS receiver or if you have one of the above
> mentioned radios it will display a
distance and direction to the landing
>
site.
>
> Andrej
> ________________________________
> From: Richard Nakka <richard.rocketry@xxxxxxxxx>
> To: sugpro@xxxxxxxxxxxxx
> Sent: Tuesday, February 10, 2015 4:36
PM
> Subject: [sugpro] Re: Hello
Sugpro
>
> Amazing
work, Andrej...! Your rockets are beautifully crafted.
> Congratulations!
> I
particularly like your nice flat thrust curve, that's
KNDX, right?
>
> GPS
is a clearly a real boon to rocketry recovery, as your
flights
> demonstrate. I recently
purchased a big red bee GPS and look forward
> to flying it soon....although I must admit
I haven't quite figured out
> how to
use it ...
>
>
Richard
>
>
>
>
>
>
>
On Tue, Feb 10, 2015 at 3:16 AM, Andrej Vrbec
> <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
>>
>>
Hello guys
>>
>>
I have just recently found out that Sugpro is active again.
I really
>> missed
>> it, as it was always fun to read what
others are doing with sugar
>>
propellants.
>> Recently I have
sucessfully flown a sugar rocket to 8km. Here are the
>> videos
>> of the
motor static test and the flight:
>>
>> https://www.youtube.com/watch?v=Q2YJtmsqKSU
>>
>> https://www.youtube.com/watch?v=z4QmCuDgi_w
>>
>> https://www.youtube.com/watch?v=zImHsYWY9-s
>>
>> Before that I
also made a sucessfull flights with a 100mm M motor. You
can
>> see the videos here:
>>
>> https://www.youtube.com/watch?v=JJlIXvbbtNA
>>
>> https://www.youtube.com/watch?v=d_AweYPlwkk
>>
>> How many
subscribers is there currently? I hope that most of the
folks
>> from
>>
the old Sugpro will join the new list.
>>
>> Best
regards
>> Andrej Vrbec
>
>
>
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