This new NEXUS model from Discount Rocketry - ModelRockets.us might have the winning design edge.
While a few of the Estes E2X models are glueless or snap-together, the modelrockets.us Nexus gives the students the feeling they are actually assembling a rocket.
ModelRockets.us Nexus Model Rocket Kit (with Streamer) for $7.14
The first Patent Pending Glueless Model Rocket Assembly System of it's kind.
"It doesn't get an easier than this. A completely glueless rocket kit with unique through the wall fin mounting and integral motor mount using model rocket Kraft tubing for the motor mount and body. Assembles just like regular level 1 model rocket kit, but without any glue!"
A complete construction video on YouTube: CLICK HERE
I found the centering ring /fin lock feature interesting. No glue! The engine mount is locked in place by the thru-the-wall fin tabs. The root edges of the fins are locked on external rings.
This reminds me of the older external MPC/Quest fin locks, but the design is new and cleaner. For that matter, Aerotech rockets have internal fin lock tabs, but here it is on a smaller scale.
The video shows parachute assembly. The 12" parachute looks thicker than most, but the thicker sheet allows you to cut it out easily with scissors. The Nexus rocket is available with a parachute for $1.30 more. Heavy walled BT-50 sized tubes are used - another plus.
This "Glueless" concept is Patent Pending. It's too good of an improved design not to be protected.
I only had one concern with the video instructions - every tied knot is call a "double knot". If two overhand knots are tied on top of each (the same direction) other you end up with a "Granny". Granny knots can slip and open, not a reliable knot. Tie a Square Knot, also known as a Reef Knot.
How to tie a Square Knot: CLICK HERE
Hey, Chris,
ReplyDeleteYou and I are working in parallel!! This past Saturday I bought the Estes '3 Bandits' E2X kit to build with the two grandkids. I'll be posting this build tomorrow on the blog. I think it's pretty cool that a couple old BARs like us can step away occasionally and build a simple beginner's kit just for fun!
Oops, my bad... I thought you were doing a build on this one yourself. It's a construction video that you're describing.
ReplyDeleteHi Ed,
DeleteI'm not building this one one on the blog. It is a very clever construction method using no glue. I think it is better than the other school or group build kits out there.
I did a rocketry program at the library where my daughter works this summer and used ModelRocket.us Turbo tube-fin rockets for the kids to build. Worked ok though the general lack of construction skills was a bit of a surprise. In retrospect the Nexus might have been a better choice and we could’ve made it a one day program rather than two - had to let the glue dry overnight (not worth the risk using CA - it doesn’t mix well with younger kids!). Everyone did ok with the build and with the launch the next day but using the Nexus model would’ve let us focus more on flying rather than building.
ReplyDeleteI’m always on the lookout for good first-timer’s models as I find myself working with groups of kids from time to time (most recently a little over a week ago leading the build of about 40 Alphas at the Museum of Flight in Seattle). In a thread about schoolyard demos over on TRF someone mentioned the Nexus and I took a look and was intrigued. This led to me ordering three of them (two streamer, one parachute).
ReplyDeleteShortly after they arrived, I put one of the streamer version together late one evening - it took all of about 10 minutes to do. Except for one spot where you briefly wish you had three hands (putting the first fin in while juggling the two support rings and getting the motor mount assembly in the right spot relative to the notch in the fin and the body tube slot) it’s just about as easy to assemble as they suggest.
I was surprised at the size of it - that heavy-duty BT-50 (call it ST-9) body tube is 12 inches long. So...lots of room for the recovery system. Flying weight is similar to an Alpha III - about 1.3 ounces. It doesn’t fly quite as high on the same motor as an Alpha III however. I get about 400 feet on an Estes B6 and around 775 feet on an Estes C6 (data via flying it with a FireFly aboard).
It’s also about the only model for which I have multiple flights’ worth of data that doesn’t go at least twice as high on a C6 as a B6. I think that’s probably a drag thing. The fins have square edges (and are thicker with no root-to-tip thickness taper as on Alpha III/IV/VI). There is also the two fin-attach rings which are about 1/16 inch thick. These also carry loops that serve as the launch lug and are both thick and stood off from the body a bit.
I was a little concerned about having the launch guides so far down on the model - well below the CG - but they seem to work just fine.
The streamer version comes in pretty hot - about 30 ft/s descent rate (again FireFly data) and it generally pops one fin partially loose on landing. But the plastic used doesn’t seem to mind this and shows no sign of damage from repeatedly re-seating a fin. The kit description on discountrocketry.com says they’re polycarbonate - so rugged stuff indeed.
The red parts also almost glow - even more so than the orange Alpha III parts - so it’s easy to see in the sky and on the ground.
All in all, I like it and have already recommended it to folks at the Museum of Flight for one of their programs where they have used an assortment of random kits and RTFs in the past.
Yes, modelrockets.us parachutes are thicker (I’ve built a few of their other models) and have a fairly unique somewhat stiff shroud line material. Once assembled they are rugged ‘chutes but tying the knots in the shroud lines can be a bit fussy. I expect the parachute version of the Nexus will take at least twice as long to get ready to fly because one has to assemble the ‘chute.
By the way, I am pretty sure that modelrockets.us actually makes the SpaceX Falcon 9 kits as those kits have the same type of parachute and also the distinctive motor hook (with a much smaller fin tab than the Estes 18mm motor hooks).
Hi Bernard,
DeleteThanks for taking the time to write up your comments on the Nexus rocket.
I called up the owner of modelrockets.us and had a good conversation about the Nexus. I didn't know it has been available for over two years. He did say he likes the heavy walled body tubes.
That fall rate on the streamer model seems fast. If I talk to him again I'll mention your recommendation to the M.O.F.
I did read that modelrockets.us did some work on the Space X Falcon 9 kit. That one was not a favorite of mine, the body wraps were terribly done, wrinkled and not straight.
I've mentioned to them that I recommended the model to the MoF.
DeleteTwo years?!? Wow.