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-   -   US Rockets Trident build thread (http://www.oldrocketforum.com/showthread.php?t=17675)

Les 01-05-2019 09:05 PM

US Rockets Trident build thread
 
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This is a new kit from US Rockets. In fact, so new I discovered I am actually a Beta tester (which I did not realize at the time that it was not a production kit). It does not show up on their web site yet. I found out about the kit via their Facebook page.

Frankly - I have to admit I am a bit disappointed. As I previously stated, this is a beta kit - but I was not informed that it was still in the beta stage. The only instructions are a copy of the Estes instructions. The kit includes a note stating it "doesn't officially exist yet" and that the kit contains "No custom parts and only used stock parts". As such, the Trident is, well, Trident-ish. One issue is the scale. The tube diameters are 2.26x the BT5 and 2.31X the BT50. But the lengths range from 1.88x to 2.22x.
The nose cones are a bit confusing. There are 3 pod cones made of plastic and 3 pod cones made of balsa. My first thought was to use the balsa on the rear where the balsa fins would glue. But the balsa cones are shorter than the plastic cones and the longer cones belong on the rear. Even if I use the plastic on the rear, the cones range from 1.55x to 3.28x. The scales are worse if I put the balsa on the rear.

Now, there was some cleverness in the design. The original Trident used a 5E nose cone, 18" BT5 tube, and 5W tail cone for a total length of 22.13. The US Rockets Trident has a 3.75" nose cone, 36" of tube, and a 4.25" tail cone for a total of 44", or about a 2x scale. Similar for the passenger pod (works out to 1.98x). However the motor pod works out to 2.49x. I did notice the fin template states it is for a 2.25x upscale.
Bottom line, since there are different scales and no real instructions, I will be needing to decide where to cut the ducting ports.
The other issue is a blown up copy of the Estes Fin template is provided. However, since the cones are not scale the pattern will not line up. Again, I am going to need to "fudge" things. The fin material is 1/4" thick x 6" wide balsa.

To give an idea on how the rocket will look, I laid out the parts next to my Estes clone.

Les 01-05-2019 09:10 PM

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Time for spiral filling. The pods consist of 3 - 12" tubes, and they are the same size as the motor tube - so 10 tubes. I can set up a bowling alley! Plus the "passenger" and "motor" section.

Did some cleanup of the Trident rings. A before and after picture. Still want to fill the edges for the exposed rings.

LeeR 01-05-2019 09:39 PM

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The nose cone on the motor section of the original is a 50J. You could give that pointy cone a flat top to more closely align with the original.

Here is my scratch-built 2.3X collection of parts. Six nose cones done, three to go.
I thru this picture together last year. Ducting tubes are not full length, I need to splice extenders on. Upper tube nose cones are reversed, the original used a 50K (Alpha) cone on top, a long 50Y at the bottom of the tube.

One of these days I’ll get those nose cones turned, and finish the build.

Looking forward to seeing yours completed.

ghrocketman 01-05-2019 09:41 PM

I hope this one makes production.
Will go good with my upscale Scorpius and Colonial Viper.

BARGeezer 01-05-2019 10:09 PM

I'm looking at the US Rockets Facebook page and the last post was Sept. 25. Where, exactly, is the Trident mentioned?

Les 01-06-2019 07:09 AM

Quote:
Originally Posted by BARGeezer
I'm looking at the US Rockets Facebook page and the last post was Sept. 25. Where, exactly, is the Trident mentioned?


You have to go back to August of 2017....
I purchased it the beginning of 2018 and I am only getting around to building it.
I am somewhat surprised that it still is not on their website after a year and half

Les 01-06-2019 07:21 AM

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Trident - made some decisions - and need to make more - Comments welcome!

First - I did not like how the pod tail cone was so short and didn't line up with the fin pattern. So I ordered some other cones from eRockets. Man they got here fast!. Shipped Thursday. Initial tracking stated they would be delivered Tuesday and showed Saturday! Here is how the new cones look.

But now my next decision. Based on the tube diameters and the fin, I'm going with a 2.25x scale factor. Used the dimensions from the Estes kit to mark and place the rings on the engine mount. Not bad looking....

But then I thought to check the engine mount to the body/nose cone - whoops. You can see that the cone won't seat fully. And no path for the exhaust gasses.

I see 3 options:
1) Make the body tube longer - but it is already at 2.22x. Making it longer will become non-scale
2) Just shorten the motor tube. I presently have CTI 3G and 6G cases with spacers. The motor tube is presently 12". The 6G case is 12.6". So I can shorten the motor tube and limit myself to 3G motors max. Although I could still be set up to allow a 5G case if I ever wanted more power - just need to buy the case.
3) Move the motor mount back by at least an inch. I got 2 extra rings so I could even add a 5th ring to fill some of the space (see pix below)


Personally, I am leaning for #2 but as I stated, looking for comments/thoughts.
(I did consider trying to hollow the nose cone but felt I would just mess it up)

bernomatic 01-06-2019 11:30 AM

I was working on making a laser cutting file for Jerry on the upscale Trident back in May of 2017. At that time, the idea was a 2.25x upscale, however, he was more interested in using his stock parts than in creating an exact upscale. One of the issues I was having is fitting that aft pod nosecone contour.

LeeR 01-06-2019 11:53 AM

Les,

I think you might want to hollow the nose cone. It would allow gases to get passed the end of the motor tube and “wrap back around” to get to the ducts you have to cut, assuming you are committed to ducting the ejection gases.

The other option is to not use motor ejection. This means no complicated cuts for ducting, greater strength in the structure, and more reliable timing of ejection by using electronics to blow the chute out. You are going to need a very robust joint at each junction of ducting tube to the upper and lower body tubes.

Jerry Irvine 01-06-2019 12:44 PM

I like this thread and the honest criticism. The kit is in fact in stock for immediate shipment. I don't recall him posting what he paid or how long he waited. ALL comments of this thread's nature are adopted into instructions we create. The whole idea as the poster stated is to have a Trident-ish kit using stock parts. Sport scale if you wish.

Thanks!

Just Jerry

6" and 12" is back!


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