Uni-Dent?

[les]

I love the Estes Trident. I presently have 6 versions and I still need to build the Trident 2 kit I have. Here is my collection.
Consists of a standard size Trident, a Hawk's Hobby upscale, and an US Rockets super upscale. My scratch Tri-Trident, the pseudo scratch/bash NewWay Quadradent, and an Excelsior plan pack GooneyDent.



For those not familiar with a Trident, it uses ducted ejection. There is a motor pod on the bottom, and a "passenger" pod at the top. Tubes connect the two pods. The ejection charge from the motor pod passes through the connecting tubes and the chute ejects from the passenger pod. Most of my versions use 3 connecting tubes. My Quadradent has 4. The Estes Trident 2 that I need to build has 2.

But I was thinking about a SINGLE tube version My thoughts are to use a heavy duty BT50 for the connecting tube. Another idea is to use a regular BT50 but reinforce it with an internal BT20 for additional stiffness. The motor/passenger pods will be BT60 or BT70. Make them slightly longer to increase the bonding area of the tubes. Use some dowels, wood pieces to reinforce the pod/tube joints. Figure a 24mm motor mount.

Thoughts before I commit to this?

 

[Back_at_it]

I have always loved this design and but have only built two of them. The first was a complete failure. I couldn't get it to successfully eject the parachute to save my life.

My second one I opened up the ports between the tubes to be about an inch long and that worked much better.

I think I follow your idea on the single tube but I'm having a hard time picturing it in my head. What I'm seeing is a lower booster section BT60/70 and a single BT50H hanging off one side. I think it would eject but I'd be afraid of bending the side tube on landing. You could reinforce it with a full length coupler epoxied in and maybe take it a step further with the BT 20 and a few centering rings.

Would be a neat idea and I'd like to see you try it.

 

[neil_w]

An OR render would help me understand what you're thinking here.

As for reenforcing the BT50... just use BT50H and you should be OK I'd think. Or BT50 + coupler.

But I was thinking.... and pardon the quick rough hack...


INVERSE TRIDENT

• 3x18 cluster!
• More ducting than you can shake a stick at!
• 3 BT20s to stuff tiny parachutes into!
• Fireflash styling!
• Pointy ends everywhere!
• Guaranteed to maybe fly in a generally upward direction!

 

[kjohnson]

I see something like this for a Unident.

kj

 

[BABAR]

I see something like this for a Unident.

kj

That looks like it was drawn with malicious indent.

 

[les]

kjohnson has the concept I was thinking of

But neil_w has an interesting concept. An inverse trident! A common central tube with the pods on the outside.

Now I may have 2 projects to work on

 

[les]

Also, I looked at the directions for the Trident 2. It used BT50 for the pods and BT20 for the connecting tubes. I'm starting to think I need to shrink my concept to match or consider it an upscale or a Gooney version. Not certain I want to get the single tube too long to keep it from crumpling

 

[BABAR]

Also, I looked at the directions for the Trident 2. It used BT50 for the pods and BT20 for the connecting tubes. I'm starting to think I need to shrink my concept to match or consider it an upscale or a Gooney version. Not certain I want to get the single tube too long to keep it from crumpling

Wouldn’t that be a BiDent? DuoDent? TwoDent?

 

[SDramstad]

Forget the ducting and just put an altimeter in the forward section

 

[Azamiryou]

Forget the ducting and just put an altimeter in the forward section

I think the ducting is the point.

 

[les]

Wouldn’t that be a BiDent? DuoDent? TwoDent?

I always referred to it as the BiDent, but the official kit name is Trident 2

Forget the ducting and just put an altimeter in the forward section

I think the ducting is the point.

If is ain't ducted, it ain't a 'Dent!

 

[les]

I went for a walk. While lost in my thoughts, I came up with a name for Neil's version.

The AntiDent

And while all my other dents are white with red lettering and trim, the AntiDent will have to be painted red with white lettering and trim.

So now that it has a name it must be built!

This kinda reminds me of something from my college days. A group of us sorta jokingly considered forming a "club" on campus. But it always seemed like just talk. One holiday break while home visiting my family, I suddenly came up with a name for the group and made a rough sketch of a logo. When I got back I showed it to the group and suddenly by having a name galvanized us. We presented our group to the Student Union, got recognized and some funding and voila, we were official! What's more amazing is the group is still in existence and thriving 48 so many years later.
Yep, I'm old...
Which allows me to ramble on with stories from them good old days
BTW - if anyone here went to RPI, let me know....

 

[BEC]

Wouldn’t that be a BiDent? DuoDent? TwoDent?

The Trident 2 is often derisively referred to as the "Bi-Dent".

I have the bits to do a GoonyDent (even the decals, I think). I need to get on that one. And I love flying my Semroc-kitted Trident. Carl laser cut the gas passages, so they are larger than the original directions have you cut, and that made a bunch of difference in getting it to work properly. I built one the old way first, and an ejection charge blew out the side of the lower body (while deploying the 'chute anyway).

 

[lr64]

That single offset tube had better be very stiff, or the rocket will do some interesting things during ascent. I guess
a thin central tube just wouldn't be the same. If I was making a unident of either sort, I'd consider better materials than cardboard or fiberglass for the thin tube. Carbon fiber or wood. Or at least some reinforcing strips.

 

[les]

The Goonydent in my photo is actually my second one. The first one I put too large a chute in and it floated away....

 

[neil_w]

I went for a walk. While lost in my thoughts, I came up with a name for Neil's version.

The AntiDent

Good name.

Thinking a bit more about this, triple deployment from the center ducted tube is unlikely to work. Would have to think carefully about this (apart from the fact that it looks ridiculous).

 

[NTP2]

Good name.

Thinking a bit more about this, triple deployment from the center ducted tube is unlikely to work. Would have to think carefully about this (apart from the fact that it looks ridiculous).

you only need 1 to work in order to get it back though. that's a 1/3 chance, pretty good

 

[Azamiryou]

Good name.

Thinking a bit more about this, triple deployment from the center ducted tube is unlikely to work. Would have to think carefully about this (apart from the fact that it looks ridiculous).

Internal tubes to duct each motor's ejection charge to one of the nose cones.

 

[les]

Thinking a bit more about this, triple deployment from the center ducted tube is unlikely to work.

Yeah - I was thinking about that. Once the first cone separates the pressure will blow out there and the others may not work. Then again, if the pressure pulse if big enough all three should start moving and "may" separate "simultaneously"

Internal tubes to duct each motor's ejection charge to one of the nose cones.

A concept I also thought of as a solution....

Right now I am checking my part stash to see what NC I have.
I have standard Estes BT20/50 tubes. Agree I need to stiffen the Unident coupling tube though.

On the Antident, I will need to move the fins forward. The rings will sit out in the air stream, but I want the multiple cooling, plasma, whatever rings on the motor tube that all (well, except the Goony version) have

 

[neil_w]

On the Antident, I will need to move the fins forward. The rings will sit out in the air stream, but I want the multiple cooling, plasma, whatever rings on the motor tube that all (well, except the Goony version) have

If you want me to work the OR file for you let me know.

 

[les]

Thanks. I will probably take you up on your offer but need to percolate some concepts first. I don't want to exercise you unnecessarily
If I proceed with the independent inner tubes, it will need to grow to a BT60 so I can use BT20 tubes internally.
Concerned with dropping down to BT5. Existing Trident had quantity 3 BT5 for 1 motor. The Bident reduced from 3 to 2 tubes, and grew the tubes to BT20. My concern is the energetic BT20 size motor blowing out the joint with a tube that could only handle a BT5 size motor....

Hmm - what about the central tube is just 3 BT20 tubes glued together?
Blue are the center connecting tubes, orange are the motor and passenger pods, the black lines are the ducts, the red lines are the fins. A second version with the fins coming out in a non-conventional position.




One possibility of the 3 separate central tubes is at the top the lengths could be staggered....

 

[neil_w]

I believe that is basically 3 UniDents bundled together?

 

[les]

I believe that is basically 3 UniDents bundled together?

yeah, guess it would be. OK - back to the single BT50 with no internal tubes.
Or another idea. Include some baffles in the top passenger modules. Not needed to protect the chute (get that from the ducting) but more as a restrictor so if one nose cone comes off first there would still be pressure for the other tubes.

Or just go with the original concept, no internal tubes, no restrictor. So long as one chute comes out it should return safely (but be subject to damage). Two should be sufficient for an undamaged landing. In fact maybe hard seal the third tube

 

[Azamiryou]

BT-55 has more than three times the cross sectional area of a BT-20. If you use dividing walls instead of tubes inside the main body, your ducts can be just as roomy as the BT-20.

 

[les]

Now I just need to figure out how to make those dividing walls...

 

[neil_w]

Sorry to send you off on such a goofy tangent.

 

[Azamiryou]

Now I just need to figure out how to make those dividing walls...

Strips of balsa? Or plywood?
3D print them?
Re-shape BT-20 tubes?

 

[mjennings]

I have a Fliskits USS Grissom (basically a Trident) this thread is really making me want to get to. Real interesting work discussion. Splitting the center tube could likely be done with card stock, might be easier to work with, and possibly lighter than balsa deviders.

A naming question is Anti Dent related to Author Dent? Don't Panic she gave him the bathrobe!

 

[ReynoldsSlumber]

What do you think about the aesthetics of different tube diameters? Personally I preferred the beefier BT-50/BT-20 combination of the Trident II over the BT-50/BT-5 setup of the original Trident.

In a different design, I tried reinforcing a BT-20 using a BT-5 down the middle, but it didn't help much, since most of the stresses are carried through the perimeter of the cross section. An alternative idea for reinforcing a tube is to just glue more layers of paper around it, as if you were rolling a tube from scratch except not entirely from scratch. It would mean you'd need to lathe larger-diameter balsa nose cones to match.

 

[lr64]

What do you think about the aesthetics of different tube diameters? Personally I preferred the beefier BT-50/BT-20 combination of the Trident II over the BT-50/BT-5 setup of the original Trident.

In a different design, I tried reinforcing a BT-20 using a BT-5 down the middle, but it didn't help much, since most of the stresses are carried through the perimeter of the cross section. An alternative idea for reinforcing a tube is to just glue more layers of paper around it, as if you were rolling a tube from scratch except not entirely from scratch. It would mean you'd need to lathe larger-diameter balsa nose cones to match.

Or you could add the paper on the inside. Roll it up to slightly smaller than the inside of the BT-20, using slow curing glue, then slip a long balloon of some sort into it, and put inside the tube. Inflate the balloon and wait. Just an idea.