Welcome to (formerly Essence's Model Rocket Reviews or EMRR). is the home of almost 5000 reviews of rocketry kits and products. Written by visitors to like you, the reviews cover everything from low-power model rocket kits to high-power rocket motors.

The site's Flight Log allows you to record and share your rockets and their flights.  The Builds feature helps you document your rocketry projects. 

At, you'll also find a large collection of rocketry resources such as a list of rocketry clubs, a calendar of rocketry events, and large libraries of OpenRocket design files and Rocksim design files. A number of rocketry tools and calculators are available to help you design, build, and fly your rockets.

As you explore, you'll also find a number of fun things such as a huge library of rocketry videos and a collection of photo albums.


The mobile site makes it easy to add flights to your Flight log using a smart phone or tablet. Visit:

The mobile site allows you to view and enter flights in your Flight Log and to view and add rockets to your Rocket Gallery using simple controls designed for smartphones and tablets. You must have an existing account which the mobile site will ask you to log into.

See Also:

Today's Featured Review

AeroRocket - FinSim {Software}


Contributed by John Champion



John Cipolla offers a great computer program called FinSim that allows one to do structural, aerodynamic and aeroelastic analysis of rocket fins. Equally impressive is his discussion located on the FinSim Website and the link to a paper describing the details of the fin flutter and divergence method. Mr. Cipolla wisely suggests that when using FinSim to estimate flutter velocity, one should bound the flutter prediction by using the theoretical 2-dimensional lift coefficient (2 pi ) to establish a lower bound and the 3-dimensional lift coefficient to establish an upper bound. Most likely the flutter velocity will fall between these two extremes.

The purpose of this review is to put an emphasis on Mr. Cipolla's advice and to suggest that the lower bound be taken more seriously as a means to design fins that will not flutter.

There are two technical reasons that support this position, namely model (equation) applicability and the neglect of the natural frequency in plunging. Both result in the reduction of a rather complex problem into a simple relation to predict flutter velocity. These simplifications result in an incremental over-prediction of flutter speed. The more conservative approach of using the 2-dimensional lift-coefficient disguises the effects of these approximations. If I have peaked your interest, then please read on for further explanation.

Model Applicability -

The approach used in FinSim is known as a quasi-steady approximation to predicting flutter speed. This approximation assumes that the frequency of vibration (oscillation) is small relative to the linear flight speed of the rocket. This relationship is often described as a reduced frequency given by the simple equation:

Reduced (normalized) frequency of vibration


Frequency of Vibration, Hz

Average Chord of Fin, unit-of-length

Linear Rocket Velocity, unit-of-length per second

The quasi-steady approximation is considered valid when the reduced frequency is small, that is when k.<= 0.1 This is rarely the case for subsonic flow (Mach number less than ~0.8). The quasi-steady approximation is best suited for the prediction of flutter speed in supersonic flow, or for use in design studies where trends are of interest rather than an accurate prediction of flutter speed.

The Effect of Neglecting the Natural Frequency in Plunging –

The quasi-steady equation for flutter speed in FinSim relates the flutter speed as directly proportional to the natural frequency in torsion (twist) and neglects any effect due to the natural frequency in plunging (bending). Again, this assumption results in an incremental over-prediction of flutter speed. The error can be minor or quite significant, depending on the magnitude of the square of the natural frequency in plunging relative to the magnitude to the square of the natural frequency in torsion. The error tends to increase as fin aspect ratio and taper ratio decrease. If the natural frequency in plunging were accounted for in the quasi-steady approximation, then the flutter speed would be proportional to the square root of the difference in the square of the natural frequencies, that is:

The %-error due to this approximation alone is calculated as follows:

In conclusion, the additive error of these two approximations could result in a significant over-prediction of the actual flutter speed, particularly if one were to base their calculation on a lift-coefficient corrected for 3-dimensional effects.


Browse our database of about 4,200 reviews of rocketry kits and other products.

Today's Featured Flyer

Ken E. Coyote

AKA: Ken E.Coyote

Location: GWL, NY

Club Memberships: NAR, Metra Rocket Club

Favorite Rockets: Rocketarium Mega Vortico


Although I always wanted to get into rocketry I never really got the chance since I grew up in a crowded city.  However I did fire a ridiculous amount of small bottle rockets when I was younger (I would hope that counts somewhat! :)  I've loved building things growing up...static model kits were the norm and I got into RC models as I got older.  I also love wordworking and any type of craft which involves making stuff.  Rocketry seems to be the perfect fit for me!  I LOVE the multi-media nature as well as the point that the rocket doesn't have to have a perfect paint job to look good (especially good if your eyesight gets worse as you age).  Great bonus is that these rockets aren't static and can be blasted off into the great blue yonder and (hopefully) return safely for another go.  I'm the creative type and I love the diversity of kits out there...this hobby is screaming for me to go crazy with silly (but safe) designs.  I've just started rocketry in 2014, but wow, I've learned a lot!

Thanks for reading! 

Favorite Quote:

Wile E. Coyote is a genius!  Laughing

You know you're a Rockethead if you go to the store or supermarket and start thinking "I think I can make that into a rocket"!



Club Home Page:

Visit Ken E. Coyote's

Visit the Who's Who directory.

Today's Featured Photo

NEFAR Launches

March 2013 Launch


Photo by Roger Smith

Rocketry Deals

Product NameList PriceSale PriceDiscountStore
Scientific Explorer's Meteor Rocket Science Kit$23.99$12.9945.85%
Estes 2274 Recovery Wadding$7.99$4.4943.80%
Badger Air-Brush Company Minitaire Color Paint Set with Color Coat/Paint Retarder$271.40$155.0442.87%

Click a column header (Product Name ...) to sort the table by the selected column. Click the column header again to sort in the other direction.

Visit the Rocketry Deals Finder to discover more specials.

Other Interesting eBay Items

1/144 scale Soviet SS-6 "Sapwood" Heavy Strategic Missile model kit by Maquette
SEALED Estes BLUE NINJA 1300 Flying Model Rocket Kit SEALED $39 retail
Vintage Flying Estes Model Rocket Sealed #1361 - SKYTRACER
Vintage Flying Estes Model Rocket Sealed #1371 - STARSHIP NOVA
Vintage Flying Estes Model Rocket Sealed #1374 - Attack Craft ORION
Vintage Flying Estes Model Rocket Sealed #1375 - SCORPIUS
Vintage Flying Estes Model Rocket #0831 - Mini-Brute STARBLAZER
Vintage Flying Estes Model Rocket #1274 Star Trek KLINGON BATTLE CRUISER
Vintage Flying Estes Model Rocket Sealed #0863 - STARLINER
Vintage Flying Estes Model Rocket Sealed #1971 - NIMBUS
Vintage Flying Centuri Model Rocket #5308 - Super Kit U.F.O INVADER
Vintage ESTES Mercury Redstone Flying Model Rocket Kit #1921 NOS
Estes And Semroc Model Rockets

Featured Rocketry Blog Posts

Model Rocket Building: Estes Apollo Little Joe II, Background
Here's the Little Joe I remembered wanting. The BIG 1/45 Scale Little Joe II from the 1969 Centuri catalog. To see the catalog, CLICK HERE But $12.95? All I could afford was the smaller 1/100th scale Little Joe II. The fin fairings and some trim was vacuum formed. They were lightweight but fragile, much like the Centuri Saturn V fins and fairings incorporated into the Estes re-issue Saturn V kits. The "metalized" wrap was pre-installed at the factory. To see the original Centuri instructions: CLICK HERE The body and capsule came down separately on two 24" parachutes. A three engine cluster. ...
[Read More in This Series]

Model Rocket Building: Estes STM-012 Kitbash to the B32-M Spike, Background
Well, I thought it might work! I bought two Estes STM-012 kits on Ebay with the hopes of kit-bashing one of them into an AMRAAM. It never even occurred to me that the STM-012 model would have three through-the-wall fins. The AMRAAM has two sets of four fins. I would have to buy a couple new lengths of BT-60 to do the conversion. That, and the STM-012 nose cone was long! So the kits sat for a few months with me wondering what to do with them. Then I remembered this design from Madcow: The AGM-33 Pike . I've always like the looks of this one, I did the instructions for their 1.6" diameter kit. ...
[Read More in This Series]

Model Rocket Building: Corner Chip Fill - TIP
Well, we've all been there - the balsa grain runs in such a way that the trailing edge tip can break off. If the tip break is small you can fill it. Sand off some balsa dust from some scrap balsa. Don't sneeze. Apply some yellow wood glue to the broken corner. Use wood glue for this, yellow glue can be easily sanded. Press the glued corner into the balsa dust pile from all sides. Let the balsa dust and glue dry. Note in the inset picture that the dust and glue is a little larger than the chip area. Here's the same filled corner after filling and sanding to surface. Not perfect, but ...
[Read More in This Series]

Rocket Dungeon: Mini Higgs build, part 1
I dug into the build at the very best place to start - at the very beginning, which in this case is the motor mount. This is not so different than any other LPR mount. It includes rings (squares in this case), a motor clip, motor block, etc. The mount also has two normal round rings to hold the clip securely in place. The Kevlar leader is attached behind the forward square centering ring. Unlike any kit I've had, it also includes a section of shrink tube to protect the lower several inches of the Kevlar. I pretty much built this stock. If I want to put a bigger motor in one, I will have to ...
[Read More in This Series]

Model Rocket Building: Carded Red Max Build, Part 1, Parts
I've seen a few pictures of "Rocket Families" on the forums. The Red Max is a favorite with the Estes Mini Max (BT-50 based), standard Red Max (BT-60 based) and Mega Red Max. Well, how about a smaller BT-5 version for 13mm engines? This one is tiny at just 5 1/4" tall! It performs like a BT-5 Mosquito. At one time I had a little carded Red Max model. It was a BT-5 diameter with a Micro Max engine mount. I lost it somewhere along the way and wanted to make another one. After a few searches I couldn't find it. I thought it might be at Wayne Hill's Rocketry Blog - CLICK HERE There are many ...
[Read More in This Series]

[View All Featured Posts]

Today's Featured Video

2008-11-08 NEFAR Mega Cereal Bowl

View our collection of about 5,800 rocketry videos.

Latest Blog Posts

Visit the Blog for more rocketry news and information.

Latest Reviews

Latest Builds

Web Search

[Configure Your Home Page]

- Link to this Page -