You can have more than one objective! The crux to me is airframe stress impact
over time from multiple O flights. Historically before SpaceX (BSX) rockets
were “single use.”
I also did have an ulterior motive. I was hoping to seduce you into a paper
that would demonstrate an aluminum rocket is no more or less safe than a CF
airframe. It is beyond my capabilities but I think worth exploring.
I do hope you can make XPRS and show us Tin Man.
On Apr 3, 2020, at 8:35 PM, Gordon Balena <g_balena@xxxxxxxxxxx> wrote:
Hi William,
This was extremely nice of you and I really appreciate it. I’ll read through
the docs and see what I can find. But the truth is this rocket didn’t need to
be all aluminum to achieve it’s objective. I simply love working with metals
and I also love pushing the envelope and try new things. To me that’s how the
hobby grows. The fact that we are flying in space now proves that.
I have two rules of thought on the hobby, where it is now and where it’s going.
I think there is room for growth becoming more high tech, challenging and
exciting but the regulations must grow too. The flip side of that is being an
engineer and seeing some of the things people are doing, (mostly on youtube
rocket launches around the country) it makes me very nervous. I’ve seen many
rockets that are completely unsafe in my opinion. My concern is that something
will happen and then we’ll have the ATF back supervising our every move.
Jim I saw your e-mail about Balls. From what I hear about Balls it would not be
a fit for me. I’m an engineer with OCD and compulsive about safety and
perfection. From what I hear about Balls it would make me freaken nuts😊 No
offence to Balls!
I’m really okay with this guys. For me a lot of the joy is creating something
special.
The rocket is hanging up in my shop and I’ll get to look at it for years to
come.
Gordon
Sent from Mail for Windows 10
From: William Kellermann
Sent: Friday, April 3, 2020 7:57 PM
To: aeropac@xxxxxxxxxxxxx
Subject: [AeroPAC Chat] Re: Spring AEROPAC newsletter
Gordon,
I would hate for you not to fly the rocket at XPRS. I just want to be sure we
do our due diligence beforehand. While I won’t speak for Gene, I’m not sure
many of us were aware of the TRA interpretation of the rule when you flew
Silver Bullet last year. At least I wasn’t.
To comply with the rule, you have to show you are using the minimum amount of
metal to withstand the stresses on your rocket over multiple O motor flights as
designed. While TRA states that the showing is subjective, I don’t think it
has to be.
Since you are a mechanical engineer, you could calculate the stresses and show
the relative benefits of aluminum over commercially available carbon fiber (or
even Fiberglas or cardboard,) while also demonstrating comparable crumple
effects from a ballistic landing.
I am not an engineer and am probably overstepping, but these two documents may
help you:
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700027342.pdf
http://www.amalgacomposites.com/material-properties.php
If you are willing to do the math, it would also help us set a more than
“subjective” standard that would benefit the club as a whole in multiple ways
now and in the future.
I would also be interested in the standard used (If any) by the TCC RSO to meet
the rule when you flew Silver Bullet there.
William Kellermann
Secretary & Corporate Counsel
Aeropac
wtkjd@xxxxxx
On Apr 3, 2020, at 7:17 PM, Gordon Balena <g_balena@xxxxxxxxxxx> wrote:
I totally get that Jim. I have seen the Tripoli doc before and it’s very vague
and I think a little out dated. We all know how much the hobby has grown in
recent years. Hell we are flying homemade rockets in space now! And I know I’m
not the first guy to build an all aluminum rocket. I have seen several in
recent years. But I totally get your concerns. I’m a mechanical engineer and
used to design experimental airplanes. I have a full machine shop and just love
working with metal😊
Well here’s my feeling on the matter. Even though this was almost a years work
and about 5 thousand dollars in materials, I’m not going to bring it. I don’t
want to raise any eyebrows or make anyone uncomfortable. I thought because
this was the “Extreme Powerful Rocket Ships” launch that we could push the
envelope a little as long as we were being safe and careful. After all we are
not Balls😊
There we so many people that really loved seeing the Silver Bullet last year
that I thought this might be something that would really add to the excitement
of this years launch.
Thanks anyway guys,
Gordon
Sent from Mail for Windows 10
From: Jim Green
Sent: Friday, April 3, 2020 6:55 PM
To: aeropac@xxxxxxxxxxxxx
Subject: [AeroPAC Chat] Re: Spring AEROPAC newsletter
Just want to make sure what your reasoning is for the amount of metal and how
that relates to the writeup from Tripoli. If there was a mishap we wouldn't
want the insurance companies to deny coverage because of a safety violation.
Jim
On Friday, April 3, 2020, 6:40:28 PM PDT, Gordon Balena <g_balena@xxxxxxxxxxx>
wrote:
Hi Jim,
I flew the Silver Bullet at 2019 XPRS with the approval from Gene after a full
inspection.
I also flew the Silver Bullet twice at Tripoli Central.
The Silver Bullet and Tin Man are both made of T-6061 aluminum for the
airframes, and T-7075 Aerospace Grade Aluminum for the fins and attachments. I
have full RocSim docs.
I reached out to several directors at AeroPac last year before bringing out the
Silver Bullet.
Do you foresee a problem with me flying Tin Man at EXPS in September?
Here is another project I recently finished that I plan on bringing to XPRS in
Sept.
<3C5F777C2AF84737A55E0E0EE6DF0C67.jpg>
Sent from Mail for Windows 10
From: Jim Green
Sent: Friday, April 3, 2020 5:51 PM
To: aeropac@xxxxxxxxxxxxx
Subject: [AeroPAC Chat] Re: Spring AEROPAC newsletter
Looks pretty.
Here is the writeup from Tripoli concerning the use of metal in rockets. What
kind of aluminum is used? Does it qualify?
http://www.tripoli.org/Portals/1/Documents/Safety%20Code/Metal%20in%20Rocket%20Construction%20v2.0.pdf
Jim
On Friday, April 3, 2020, 3:31:05 PM PDT, Gordon Balena <g_balena@xxxxxxxxxxx>
wrote:
<D3511218AC4B4BCF94821813268F5A78.jpg>
<5A45BD7C0222495E82ABFC49447AD048.jpg>
<B7ACFAC85DB446FABFE7AE8E2066FE6E.jpg>
<819FABBB5B964FA9808D1CB97CB083F8.jpg>
Sent from Mail for Windows 10
Hi Jonathan,
Here is one of the projects I worked on this winter. It’s the big brother to
the Silver Bullet, called Tin Man. It’s a 6 inch all aluminum rocket completely
scratch built of course. Let me know if you want anything more or if you have
any problems opening the pictures.
Thanks,
Gordon
From: Jonathan DuBose
Sent: Sunday, March 29, 2020 9:21 AM
To: AeroPac Members
Subject: [AeroPAC Chat] Spring AEROPAC newsletter
Hello Everyone,
It is my sincere hope that this message finds all of us safe and healthy with
high hopes for anyone who is ill.
This is my twice yearly call for articles for the newsletter. Perhaps some of
you are building projects you would like to share with the rest of the club and
here is your chance. Any other rocketry related articles are also greatly
appreciated.
Hopefully, things will have improved enough that we might be able to hold
MUDROCK in June. With that in mind, I will try to publish by June 1 so please
have your articles in by mid-May if possible.
Stay safe and healthy!
Jonathan DuBose
AEROPAC newsletter editor.
