The return of the C5...

At the end of this week, I received an email from Estes, featuring this image:

This got me very excited, for the following reasons:

• An increase in the types of available 18mm black powder motors, the number of which has been on a steady decline for the past couple of decades. Hopefully, this marks a turnaround point.
• An 18mm motor that can get the Estes 1/200th scale Saturn 5 and some other heavy birds (like the Centuri/Semroc Orion and Estes/Semroc Mars Lander) off the pad at a decent speed.
• More motors for the range box.
• I can now legally fly some of the old C5s in my motor stash.

However, my excitement was a bit dampened by some posts on the internet from folks who did not understand the need for the C5 - what was wrong with the good old C6, after all? I mean, it has a higher average thrust, doesn't it (6 newtons as opposed to 5)?

Well, let me explain why this is a great thing, and why it is the likely precursor of an even greater thing, namely, a C5-0 booster motor.

First off, the labels on a model rocket motor are just general guides - you can tell the impulse class (in this case, C, which means a total impulse between 5 and 10 Newton-seconds), and the average thrust, which is generally (but not always) the total impulse divided by the burn duration.These are helpful in motor selection, but sometimes you have to dig deeper into the motor numbers in order to discern the differences within an impulse class. The label on the motors doesn't indicate there is much difference between the C5 and C6, but the motor thrust curves show otherwise.

Estes C6 motor thrust curve (Click to enlarge).

Estes C5 motor thrust curve (Click to enlarge).

The first thing you notice is that the C6 has a peak thrust of about 11.6 newtons, dropping down to a sustained thrust of about 5 newtons for most of its 2 second burn time - total impulse close to 9.8 newton-seconds. The C5 has a peak thrust of 21.8 newtons and drops down to 4 newtons, burning out after 1.75 seconds - total impulse is 9.5 newton-seconds. Both motors reach their peak thrust at about the same time, but the C5 puts a much greater percentage of its impulse up front, meaning it can accelerate a heavy model more quickly off the pad. That's why the ad said "50% Increase in Max Thrust" (actually it's more like 47%), but you would have never gotten that just looking at the motor casing,

So, a C5 can lift a plastic Saturn 5 better than a C6, but what else is it good for? Imagine, if you will, a C5-0. This booster engine, with the bulk of its power up front, makes possible the 18mm powered 3 stagers of Yore - notably the Arrow 300 and the Farside/Farside-X. No longer will we have to stick a 24mm motor mount in the booster, as in the current Comanche-3, but can build them as the master designers intended. These motors, when they are released, will be the beginnings of a return to Eden for us old rocketeers - bring on the 3 stage clones!

In the meantime, I have a few C5-3's on order - need to encourage Estes to get around to making those C5-0's.

Plus, it will be very nice seeing my Saturn lift off on a C5!

Rockets on TV!

A lot of rocketeers are talking about a recent TV commercial that features model rockets. We are used to the occasional appearance of rockets on TV - in a "Wonder Woman" episode, occasionally showing up in "The Big Bang Theory", and in an ad by Enterprise Rent-A-Car:


The recent ad is a Jardiance commercial, featuring the goings-on at a rocket fair (Cool idea, btw). It is a full minute of rocket goodness - Check it out here.

Can you name some or all the rockets you see in the ad? If so, post a comment so we can all be amazed by your rocket identification skill!

Another 4th of July rocket...

Every year I make an effort to build a patriotic-themed rocket to commemorate Independence Day. Last year, it was an Estes America, and here are a few more from previous years. All this stuck-at-home stuff got me wondering what I was going to build this year, so I began to browse through my collection to find something appropriate. The search did not take long.

Back in 1986, Estes phased out its much loved (at least by us old guys) Estes Aerospace Club (EAC). it was replaced in 1988 by the Estes Space Program, which was, in my opinion, a stripped-down version of the EAC - not as much cool stuff. But like its predecessor, the Estes Space Program introductory package came with a "special" rocket - the patriotic Yankee Clipper, which looked snazzy with its red, white, and blue decor. In actuality, it was a recolored Estes Cougar, released a few years earlier in 1984, but I still liked the Yankee Clipper's style. So I opened the Estes Space Program bag and pulled out the parts. They were all there, so I am good for the build.

Estes Space Program page from the 1988 catalog (Click to enlarge).

But first, I had to run a few simulations...

The Yankee Clipper is a simple 4FNC (4 fins and a nose cone) bird, so entering the various parts into Open Rocket was a snap. The only tricky part was getting the decal (stickers - yuck!) scan into the program to complete the decor. But my Open Rocket kung fu is pretty good, and I finished the simulation in about 45 minutes. The flight numbers show a range of altitudes between 290 and 1070 feet with conventional Estes motors; I think she'll do her maiden voyage on a B6-4 (Imagine that!).

Open Rocket simulation of the Yankee Clipper (Click to enlarge).

The choice is made. Now it's time to start work on this model...

Listening to podcasts...

As I enter my 8th straight week of telework, I have become bored by my music playlists, so I have started to listen to a few podcasts to provide some variety. The list includes a couple of my faves, The Rocketry Show, and its recent spin-off, The Model Rocket Show. Old or young, newbie or expert, if you are a rocketeer, you ought to listen to these podcasts - they are really nice!

The Rocketry Show (now in season 6) is hosted by Cornelius Gould (C.G.), Jim Seibyl (Gheem), and Daniel Petrie (the Rocket N00b), with Jesse Ulibarri recently joining the cast while Daniel is focusing on The Model Rocket Show podcast. The show varies from episode to episode - sometimes there is an interview with a well-known rocket expert or manufacturer, sometimes you have launch or event coverage, and sometimes there is interesting rocket chat focusing on a few topics and some viewer questions - "workshop talk." Up until the beginning of season 6, The Rocketry Show tried to cover all aspects of rocketry (and they achieved a pretty good balance, btw), but I think they wisely saw the difficulties in trying to cram all of rocketry in one podcast, and so Daniel spun off The Model Rocket Show to cover LPR/MPR, leaving The Rocketry Show to focus on HPR, advanced rocketry, and STEM. And so the last few episodes of The Rocketry Show have featured discussion of rocket avionics (C.G. is an electronics wizard), an interview with Jeff Skinner of Mach 1 Rocketry (can you believe BT-20 fiberglass kits?), High Power Rocket safety, and some of the new features in Rocksim 10. If you check out the show archives, you will find a pretty impressive list of topics covered in the past seasons.

Daniel is just getting The Model Rocket Show fired up, with 3 casts so far - a premier episode, followed by the story of how he got into rocketry (in a somewhat unconventional way) and a discussion of FlisKits and their products (includes interview bits with Jim Flis and the new owners). It's a great beginning and I look forward to the next episode. Daniel has a good style and a knack for picking relevant topics to us LPR/MPR folks - his blog is proof of that.

Since they are "sister shows", episodes of The Model Rocket Show and The Rocketry Show will be released in a staggered fashion to avoid conflict. Needless to say, I like this arrangement very much, because I now have two quality rocket podcasts to listen to.

Here are the links to the podcasts' webpages (they are also available on Spotify, TuneIn, Apple, etc.):

The Rocketry Show: https://www.therocketryshow.com
The Model Rocket Show: https://themodelrocketshow.com

Give them a try (do you have something better to do in the current pandemic?), and if you like them as much as I do, throw them a little support by donating thru Patreon. A few bucks can go a long way, especially if all the listeners contribute. The hobby needs podcasts like these, so let's help keep them going!