New Glenn(first post)

[Ryan Miller]

Hey there, don’t know how these intros should go but I’ll try and keep it short since this is the LPR section not the intro section. I’m Ryan. I’m 21yo, I’ve just reignited my interest in model rockets at the beginning of the year. I have built about 10 Estes kits since and ordered my L1 kit(Torrent) to get certified this summer. I’m an electrical engineering student and Cyber Ops in the Air Force. One day I want to be building orbital rockets for a private company but hopefully I’ll still be doing this too.

Since this is the LPR section I’ll share my latest build. I got an estes designers box for 50% off at hobbytown so I decided to build a New Glenn model. The decals were printed at Office Depot they actually turned out pretty good I think. It has an 18mm mount. I’m not sure how straight it will fly given the fin and splitter size but it turned out exactly how I wanted so I’m happy with it.

 

[JERRYR708]

Welcome to TRF! That New Glenn is pretty sweet!

 

[roytyson]

1-2-3 Go. Or something like that. Welcome to TRF. Ryan’s builds are near perfect. We will enjoy his build thread for his L1.

 

[Nytrunner]

Welcome!

Great finish and decals on the new glenn.

For designing stable rockets, check out OpenRocket. It's a free simulator program that's easy to pick up, and fun to experiment with. (Look for Neil_w's Openrocket installer thread here)

 

[Bat-mite]

Cool. I like the feather.

 

[base890]

Awesome job. Let us know how it flies, I’m going to build one of those myself some day but in 4”.

 

[BDB]

Do you know if this is stable? I'm guessing it isn't due to the small aft fins and the canards. This would be a great excuse to buy Joe Barnard's thrust vectoring system.

 

[neil_w]

Do you know if this is stable? I'm guessing it isn't due to the small aft fins and the canards.

I would agree. Looks beautiful, but unlikely to be stable. Definitely run that through Rocksim or OR before flying. Or if you want then post all the dimensions (or PM me) and I’ll model it for you in OR.

 

[jqavins]

Or swing test it. Design/simulation software, OpenRocket (OR) or RockSim (RS), would give you better confidence, but a swing test is lots better than nothing.

The nice thing about OR and RS is that they give you confidence in your stability (and performance) before you build, where you obviously can only swing test afterward.

 

[BABAR]

Turned out great! Very nice first post!

 

[neil_w]

I did an eyeball job on it in OR, close enough to draw conclusions I think:


Note there are only two fins at the bottom (that's how the real thing is as well, for whatever reason). This version of the rocket will not fly, unless you count skywriting. You need to add some extra finnage at the bottom to stabilize it.

I tried a full set of four fins on the bottom:

Conceivably you could load enough nose weight into this version to make it fly straight-ish, assuming you have enough thrust to lift it. Still very little fin area in the back, I wouldn't expect it to fly "well", but who knows. Some scale missile models seem to be able to fly despite unfavorable CP by loading up sufficient nose weight.

Best solution I think is to add some larger clear fins at the bottom for stability, else perhaps just keep it as a very nice display model. Just MHO. Would hate to see that thing destroy itself attempting to fly in its current config.

 

[Homer_S]

Could always do the "flames" thing out the back!

Homer

 

[jqavins]

What's the body tube size? Cut out the motor mount and install the bps.Space thrust vectoring system? (Not so easy, of course.)

 

[roytyson]

Ryan, Modelers will often use clear acrylic fins for rockets that do not have fins in real life. This will provide stability, yet give you the "appearance" of the real thing. SpaceX models do this with their kits.

 

[Ryan Miller]

What's the body tube size? Cut out the motor mount and install the bps.Space thrust vectoring system? (Not so easy, of course.)

Not so cheap either. Do you know if those are able to be easily taken out and re-used in multiple rockets? I cant make myself spend $350 to use on one LPR rocket. I dont think it would fit in this one anyway, It is a bt60.

 

[neil_w]

My understanding is that the BPS system really has to be built into the rocket from the get-go. I don't think it's practical to retrofit.

I don't know if it's possible to move it from rocket to rocket. Seems difficult but maybe.

 

[kuririn]

Zooch style flame fins need two tubes parallel to the main motor for the fin tubes to nest into. Major reconstruction for an already built motor mount.
Maybe clear fins attached to a clear fin can? Slip on the rear and secure with masking tape (easiest) or a twist lock system (harder)?
Nice thing is it would be removeable for display.

 

[aerostadt]

Apogee sells a clear plastic BT-70 tube. It might be a little bit too large for the BT-60 or maybe just about right. I did this about 8 years ago for some LPR models. I found it not easy to glue clear plastic fins on to the plastic tube. Cutting the fins from clear plastic can be difficult, too. Quite often the fins would break off of the tube after a flight. It can be done, but my experience was not easy. Perhaps, better glues might be out there.

 

[kuririn]

One more idea: a fin can with coupler that slips onto the rear. Like a booster stage without the motor mount. Vinyl or masking tape on the outside seam to secure or friction fit the coupler with masking tape, or both:

From my Fliskits Sat 1B build in progress (like, forever).
Easily upscaleable.

 

[jqavins]

Not so cheap either. Do you know if those are able to be easily taken out and re-used in multiple rockets? I cant make myself spend $350 to use on one LPR rocket. I dont think it would fit in this one anyway, It is a bt60.

My tongue was part way in my cheek, so let's just pretend it was in all the way.

As for moving it, one could probably build it permanently into a removable tube that has centering rings to be placed into a bigger tube, making it swapable between even bigger rockets. Reading afadeev's build thread, I see that it needs "calibrating" to the rocket, so that would have to be repeated each time it's moved; it looks pretty easy. But that's rather far off topic.

 

[kuririn]

Another idea: get a 3D bt-60 screw together coupler. I got mine from erockets. Glue the half with internal threads to the back end of the rocket. Glue fins to the other half, and screw together. Unscrew for display.

 

[neil_w]

Whoa, hadn't seen those before, very cool.

 

[K'Tesh]

Nice looking build!

Please let us know what you choose to do... Don't forget to add photos, and upload links to videos of it in flight.

Pointy Side Up!

 

[jqavins]

Another idea: get a 3D bt-60 screw together coupler.

Whoa, hadn't seen those before, very cool.

My friend just bought Estes's latest update of the Mean Machine, and it includes a bayonet version of the same basic thing. It lets you split the 6½ foot rocket in half for transport. I like your suggested application.

 

[K'Tesh]

Key thing to remember is that the more weight you add to the back, the more you're going to need to add to the front to make it stable.

 

[K'Tesh]

Key thing to remember is that the more weight you add to the back, the more likely you're going to need to add weight to the front to make it stable.

 

[base890]

Add the landing legs as fins.

 

[neil_w]

Anyone know why the real thing has only two fins at the back? I can't think of a functional justification for that.

 

[Ryan Miller]

Anyone know why the real thing has only two fins at the back? I can't think of a functional justification for that.

They add cross range for decent back to earth. Lets New Glenn glide closer to home during re-entry on heavy launches. Probably adds some lift too.

 

[Ryan Miller]

Another idea: get a 3D bt-60 screw together coupler. I got mine from erockets. Glue the half with internal threads to the back end of the rocket. Glue fins to the other half, and screw together. Unscrew for display.
View attachment 379192

Ive, decided to go with your idea. Will probably have to remount the motor tube further aft so it doesnt burn the plastic, its currently flush.