[The Rocketry Show] Episode #55: A Rocketry Show Holiday Party!

The team goes on the road, and set up at their club Christmas party and record a show.

Lots of rocket stories are shared.  Enjoy, and Happy Holidays!

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[The Rocketry Show] Episode #54a: Addendum – Let’s make a correction!

Chris Pearson called to make a correction to some of the distance information we shared in the initial (free) version of Episode 54…

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Star Wars – Imperial March on Eight Floppy Drives

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[The Rocketry Show] Episode #54: LiPo battery follow-up, and filing for FAA Waivers for your club!

CG follows up on the previous episode, adding some important notes about Lithium Polymer (LiPo) Batteries.

We invite Chris Pearson, Prefect for Northern Ohio Tripoli to the show to talk about what it takes and things to think about to file an FAA Waiver for high power rocketry launches.  He also talks about things to think about when doing so.

For the Patrons of our show, we will post (shortly) a much longer version of this show, where Chris Pearson fills in much of the history behind this process!

FAA information mentioned in this episode can be found here:

Filing for FAA Waiver

Laws & Regulations




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[The Rocketry Show] Episode #53: Season 4 Premiere! Straight Fins and Lithium Polymer

*** NOTE from CG: Do not use the LiPo salt water disposal method mentioned in the episode!  While it has been “common knowledge” within  hobby circles to use this method of disposal, I have found very good reasons not to do this, and I’ll talk about it in Episode 54!!!   Just take bad LiPo batteries to a recycling center***

We’re back for Episode 1 of Season 4 of the Rocketry Show!

This is a show packed with lots of information for you!   Daniel, The Rocket n00b starts with a discussion on a technique he mastered for making curled balsa and basswood rocket fins straight again!

CG chimes in during the second half to give a basic beginner’s primer on Lithium polymer (LiPo) batteries for powering your electronic systems on board your next rocket project!

References for you to follow up on what CG was talking about:

Since the show was running a bit long, and there were details CG didn’t get to cover, he has provided some quick, but important notes here:

What does the Battery “C Rating” mean?

The C rating of a Lithium Polymer (LiPo) battery (or cell) is used as a guide to show what kind of continuous current draw, in amps,  the cell in question will support.

By multiplying the C rating times the cell capacity in milliamperehours (mAh), the continuous current in milliamperes (mA) of a cell can be calculated.

In my case, the batteries I use for Nesaru are rated as 180 mAh, 25-40C.  I’ll use the lower “C” number, as I’m pretty sure the 40C is “peak” capacity – more on that in a moment.

The Turnigy LiPo battery CG uses for his rocket, Nesaru.

For this battery, the safe continuous current draw value is found by multiplying 180 (mAh) x 25 (C), which gives you 4500 mA, or 4.5 Amps.

Now, for the “Peak value”.

This is the amount of current the battery can safely deliver for very short periods of time.   In this case, the battery says its peak value is 40C.  Using the same math above, we get a peak current rating of 7200 Ma, or 7.2 Amps.

Note on Charger setting:

The battery in my example is rated for 8C max charge rate.   Doing the math (180 x 8), the safe charge rate for my battery is about 1.44 Amps.

As for the charger settings for this battery, I should stay below the 1.44 Amp charge value to stay safe.   Not pushing the battery to its limits in the charger means the cells will stand a much lesser chance of becoming unbalanced (in multi-cell batteries).  So, I typically charge this battery at a 0.5 Amps on the charger.

Why?  Because unbalanced battery cells = a really bad day in the field – if you’re lucky!

Links I found for further reading on the topic, and packed with many of the tips I gave, plus much more:

The Lithium Polymer Safety Guide

The Drone Girl blog

That swollen cell phone LiPo battery CG talked about during the show!

liPo cell phone battery gone bad!

The swelling is apparent, and even though the battery has a big “Li-Ion” stamp on the lower right corner, the fine print on top says what CG figured out when the swelling pushed his old cell phone apart…

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The End of an Era

By Chris Pearson

It was with some sadness today that I learned the iHobby Expo, formerly called the RCHTA Show, has been cancelled and is not expected to ever resume. The original RCHTA Show, (Radio Control Hobby Trade Association) was, as its name suggests, an association of RC plane manufacturers. In the fall of each year, they had an industry show, which at first was open only to hobby shop owners and others in the business. They later allowed first trains, then crafts and even things like doll houses and scrapbooking in. They also began to allow the public to attend the show. The last time I was there, Thursday and Friday until 6PM were trade days, Friday night and all day Saturday and Sunday were open to the public.

The show was traditionally held at the Chicago Convention Center, now called McCormick Place. It was the largest hobby show in the US, second only in size to the Berlin (Germany) Hobby Show. In the 1980’s and into the 90’s, if you had a hobby business, you had to be at that show. Of course, the big two model rocketry companies, Estes and Quest, exhibited their new wares to the hobby shop owners and public. A smattering of other model and high-power rocket companies also attended, such as Custom Model Rockets, Starlight Model Rockets, PML, NCR, Aerotech and LOC/Precision. However, the hobby landscape changed in the late 90’s. It just wasn’t the Internet that hurt the hobby industry or caused the shuttering of hobby shops. The interests of young people changed from hobbies like plastic models and rocketry to video games and later social media. The last president of Centuri, Jeff Flygare, complained to me at NARAM-20 (1978) that “all the kids were putting their quarters in Pac Man games and not buying rockets anymore”. So the writing was on the wall decades ago.

It also became prohibitively expensive to attend hobby shows, either as a manufacturer or a shop owner. The displays for companies like Estes, Futaba or SIG were huge and it cost a fortune to build, ship and assemble the displays at the convention center. The Chicago Convention Center is controlled by the Teamsters, so you had to use union labor to unload your truck, move and assemble your display. You want an AC outlet to plug your VCR into? $75 per day per outlet! In later years, because of complaints, you were allowed to move and build your own display as long as you didn’t need tools to do it. You could also plug in your own AC cords, and not have to wait for an electrician to do it for you. Even if you were a hobby shop owner, the motel rooms around the convention center were expensive, even if you stayed in a second rate place like a Holiday Inn. Food and rental cars were also very expensive, compared to say, Orlando.

In 2012, they moved the now renamed iHobby show to Cleveland, Ohio and shortened the show to three days in an effort to reduce costs for the attendees. I, myself and others from NOTRA ran the booth for Tripoli and our club at the show. The result of the move was that many of the big-name companies, including Lionel, Futaba, Estes and Quest, chose not to attend. They moved it back to Illinois the following year, but held it in the Schaumburg Convention Center, outside Chicago. They then changed management companies and moved the venue to Edison, NJ, but the result was even more vendors and manufacturers fled the show. After four years of declining attendance and a general lack of interest by manufacturers and the public, the decision was made this past August to cancel the show permanently. In the end, it had become a two-day mid-week show back in Schaumburg, IL, which this year was scheduled for October 4-5.

The iHobby Expo follows other US hobby shows into oblivion like the IMS (International Modelers Society) Show.

The HMA (Hobby Manufacturers Association) who ran the now defunct iHobby show has started another hobby show to take its place. It is the Rocky Mountain Hobby Expo, and it’s being held in Denver, CO. If you absolutely have to go to a hobby show, here is the link:http://www.hmahobby.org

Unless you attended one of these shows at its peak, you could not understand the incredible excitement of going into a place as big as a football stadium and have it filled wall to wall with hobby stuff. The feeling was electric! It was an absolute geek fest and hobby sensory overload! On the public days, the line waiting to get into the show was wrapped around the building an hour before opening. Even though I was on my feet for 14 hours in the North Coast Rocketry booth some days, I really enjoyed the show. I look back on those days with a certain amount of nostalgia. I will miss it.

Chris Pearson

Chris Pearson is one of the individuals first involved with LDRS, and the early days of what would become known as High Power Rocketry, and a past associate of North Coast Rocketry

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[The Rocketry Show Video]: TARC 2017 coverage. mini Episode 2: South West Rocketry’s cool rocket…

Team “South West Rocketry” from Springs of Life Christian Fellowship from Los Angeles, CA join us at our booth to discus their unique rocket design.

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The Rocket n00b’s latest project!


I built an Estes Photon Probe model rocket kit, but decided to upgrade it to a two-stage model. This is the first flight, in Acton, Massachusetts, which took place July 8, 2017.

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[The Rocketry Show Video]: TARC 2017 video coverage, mini episode 1

Gheem and CG interview Robin Thurman, Director, Workforce Policy at the Aerospace Industries Association (AIA) about the Team America Rocketry Challenge (TARC).

Continue reading

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The Rocketry Show Live! June 11, 2017

Updated 6/11/2017:

We will be audio live streaming the Rocketry Show’s recording session on 6/11/2017 after 8:30 PM.  The stream will be both on Facebook, as well as our website (for non Facebook folks) using the link below:


The website audio link is live now with test audio until the show begins tonight for you to test your devices and browsers.

The topic will be a general rocketry workshop chat, and rocket fun, and you will have an opportunity to interact with us using Discord, and Facebook Chat!

Our invite to you for Discord is here:


You can also send us e-mails using the contact us button on the site!




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