Delta III?

So let me lead with the story...
I was perusing Apogee's excellent website, and came across the "garage sale" area. I came across the 2 - 22.6mm/5.77" Tubes, which are " left over from the out of production Delta III kit."

So, I bought a pack of 6 in an attempt to perhaps rebuild the Delta III (probably one of the best performing rockets in real life, amirite?)

There are only 2 references I can find to the original kit (maybe they were separate?), which was put out by DRF Technologies (now Real Space Rockets, who make fantastic looking display models, btw). One comes from rocketreviews stating, "It is designed to be able to fly with 6 A10-PT motors and a core C6 motor in the main airframe. " Another comes from a review of the Apogee version of the discontinued product, which seems to have only used one motor.

hMy plan is to do something that in the end will look something like this :




I acknowledge that the fins are not part of the actual rocket; they are there for prevention of death by model Delta III

The top portion is BT70, the bottom portion that the booster sections are glued to is BT50. The rationale for these are: 1) The diameter of BT-50 + 2 booster tubes is approximately BT 70 and 2) 6 of the boosters can encircle a BT50 snugly enough, while leaving room for fins.

BT-5 tubes would be placed inside all or some of the apogee garage sale tubes (BT-26?). Why the 13mm? I dunno, seems simplest as historically it seems it launched on minis (plus, for reloading the thing, it coming in packs of 4 doesnt hurt at all). would be quite easy to deviate a bit, though.

Now the interesting thoughts I had for the whole build, let me know what you think or have any additional ideas that would be fantastic:

1) Load all boosters with an A10-PT (plugged), the main with a C6, with deployment of a parachute from the BT-70, as usual
2) Load 3 of the boosters with an A10-3T, load the other 3 boosters with small estes parachutes, and have a 3x rear-ejection. My preliminary simulations show that this would not be enough to slow it down, and thus a C6-3 would again be used to deploy a parachute from the BT-70
3) Load all boosters with an A10-3T, with rear-ejection of a parachute from the BT-50 tube
4) ??? (other suggestions)

Also, if anyone has the original kit instructions or dimensions, sharing is caring

This project will be thought of in-depth for a good amount of time, whilst I finish up the Cosmic Interceptor I'm currently working on, then the Partizon which is waiting in the hangar bay.

Thanks in advance!

I'd kinda like the design.
If were me, I'd go with a longer center tube, a bt-60 I think would look better.
Load all 6 boosters with A10-0, but go with a 24mm nose block and retaining set.
Go for separation, meaning, 2 chutes. One for the lower section, and one for the reducer and above.
You could even go with clear tubing for a payload bay with removable nose cone.
Idea's will fly, but with the rocket?
Consider clear lexon for the fins...

Woody,
Thanks much for the ideas. The BT60 does indeed look nicer methinks, and I suppose does not stray too far from the appearance of the actual Delta III, which I am trying to keep in line with

Im a bit confused as to your separation- where would the 2 parachutes come from, and what would be their means of ejection, if I had all 6 boosters with engines?

To clarify, when you said "A10-0", did you mean "A10-plugged"?

Thanks again, looking forward to your continued insight

Both chutes would be in the longer bt-50 center tube.
Ejection would be from 24mm motors. Using a nose block and retainer set you can use standard Estes, single use Aerotech or reloadable motors.
No, you can use plugged if you wish. If you use "0's) you will get a nice poof of smoke from the open tubes as drawn using engine hooks.
If you use nose cones, you can friction fit the mini's and they will blow themselves out to reduce recovery weight.

d11rok said:

[/B]So, I bought a pack of 6 in an attempt to perhaps rebuild the Delta III (probably one of the best performing rockets in real life, amirite?)

Click to expand...

Uhh the Delta III only flew three times, two of which were failures and the third wasn't even a complete success. Were you thinking Delta II? That rocket has a stellar record. Nevertheless, Delta III is definitely one of the coolest rockets in real life!! I don't know how accurate you're trying to get scale-wise, but it also had 9 boosters, not 6.

This is definitely a cool idea though. I would do 6 A10-0T and 3 A3-4T's in the boosters. Let the 6 A10 loaded boosters eject first with their -0 delays and the A3s would burn longer and separate later. This would make a more realistic flight pattern -- in the real vehicle 6 boosters were lit on the ground and the remaining three were airstarted and the 6 ground start boosters are jettisoned shortly after. You could try to airstart the A3's as well...but that would be much more of a challenge!

As for resources, I would contact Apogee to see if they have any other parts for this kit laying around.

Also did a little search for paper models of the Delta III. I found some that were no longer able to be downloaded but did find this:

https://www.papercraftsquare.com/delta-iii-rocket-paper-model-free-template-download.html

It's an active link to a Delta III paper model but it's a .rar file, I'm not sure what that is. I can't open it on my computer. But if you can get it open you can probably scale the parts to the size you need.

d11rok said:

[/B]So, I bought a pack of 6 in an attempt to perhaps rebuild the Delta III (probably one of the best performing rockets in real life, amirite?)

Click to expand...

Uhh the Delta III only flew three times, two of which were failures and the third wasn't even a complete success. Were you thinking Delta II? That rocket has a stellar record. Nevertheless, Delta III is definitely one of the coolest rockets in real life!! I don't know how accurate you're trying to get scale-wise, but it also had 9 boosters, not 6.

This is definitely a cool idea though. I would do 6 A10-0T and 3 A3-4T's in the boosters. Let the 6 A10 loaded boosters eject first with their -0 delays and the A3s would burn longer and separate later. This would make a more realistic flight pattern -- in the real vehicle 6 boosters were lit on the ground and the remaining three were airstarted. The 6 ground start boosters were jettisoned shortly after. You could try to airstart the A3's as well...but that would be much more of a challenge!

As for resources, I would contact Apogee to see if they have any other parts for this kit laying around.

Also did a little search for paper models of the Delta III. I found some that were no longer able to be downloaded but did find this:

https://www.papercraftsquare.com/delta-iii-rocket-paper-model-free-template-download.html

It's an active link to a Delta III paper model but it's a .rar file, I'm not sure what that is. I can't open it on my computer. But if you can get it open you can probably scale the parts to the size you need

Marcus,
Thank you much for the input! My quoted line was meant in jest...sometimes the sarcastic intonation is lost in text I suppose

Yeah, I understand it had 9 boosters, but indeed I will be editing down to 6. The initial thought of this project was to incorporate the booster tubes that I posit the apogee build used, acknowledging that these are non-standard sizes and I will need to work on each nosecone manually to some degree. Although, I could load the 6 boosters I will be using with an A10 as you described, and load the BT with 3x A3-4 instead of the C i was planning- this would lead to the correct amount of separate engines that the actual rocket had.

After simming the 6xA10-P in boosters and 3xA3-4 in the BT, it looks like that flight was unstable. however, subbing 3xA10-3 in the BT worked well, with apogee of 592'

I could also decrease the amount of boosters that have an a10-P in them to 3, leading to a sim apogee of 450'. this would obviously decrease the reality factor that is a subtheme for this build, however

Another initial thought I had on this project was to go for rear ejection through unused pods if i were to only house engines in 3 of the boosters; however, I think that the cluster of 9 would be a) very interesting, to say the least, b) more real, and c) decrease the complexity of this project just enough to give it a fighting chance of a successful flight. Deployment could be from the simple ejection charge. Ducting of ejection charge from the boosters would also be difficult given that I am using the non-standard tubes to house the BT-5

Marcus and Woody, thanks again for all your input on this project already. looking forward to eventual building and flight of this, and hope for continued ideas from you along the way! Woody, those tips you posted about this for rear ejection will certainly be useful for another project I have planned.

Current status, viewed from aft:


The circle going through the boosters is the forward BT being superimposed. Seeing this on 3D, I will be increasing the aft BT from 2.9cm to BT-55

Methinks this setup using a BT-5 within the nonstandard tubes would be a nice set up to do something like this...

https://www.apogeerockets.com/education/downloads/Newsletter260.pdf. There was a recent post down at the scale subforum that had a youtube video of a very elaborate Delta III with pods that fell back, which I now hope to attain on a very, very simmered down version

d11rok said:

Marcus,
Thank you much for the input! My quoted line was meant in jest...sometimes the sarcastic intonation is lost in text I suppose ...Marcus and Woody, thanks again for all your input on this project already. looking forward to eventual building and flight of this, and hope for continued ideas from you along the way! Woody, those tips you posted about this for rear ejection will certainly be useful for another project I have planned.

Click to expand...

Ah, my lack of sarcasm detection has failed me again! Heh heh. I do love the DIII though, successful or not. such a cool looking rocket.

And you're welcome on input. It sounds like you have the plan under control...and many options! Would love to see the flight of this.

I was unaware of the Delta III previously; now I'm going to have to investigate building one of my own. FWIW, at least from the drawings I found, it appears that if the upper section was BT70, then BT55 would be closer to scale than BT50.

Marcus, indeed with all the help on this thread a complete idea is coming nicely together! Certainly will be an interesting launch. Instead of putting this project completely on the side until I complete the next couple rockets, I may end up gradually working on this one in continuity with those

Jawa, I agree it does look like the bt55 will be better, thank you for the input. I'm excited that you're planning a build of it as well! Any preliminary ideas of engine layout, or parachute deployment?

d11rok said:

Jawa, I agree it does look like the bt55 will be better, thank you for the input. I'm excited that you're planning a build of it as well! Any preliminary ideas of engine layout, or parachute deployment?

Click to expand...

I haven't gotten anywhere near that far yet - I didn't even know about the Delta III prior to last night. All I've done so far is google it, download all of the high-res photos I could find (which wasn't many) and print out a large scale version of this drawing, so that I have something to scale from (it helps to have a roll-fed, large-format color printer next to my desk):


With that drawing open at 100% size on my monitor, the payload section measures real close to BT70 size. So I laid a scale over it to approximate the BT55 for the S1 portion.

Jawa,
that picture was uber helpful! Keeping the booster sections constant at 5.77", using your picture I was able to make ratios and delineate lengths of components as follows:
BT55 section: 7.83"
BT70 section: 8.57"
Transition: 0.82"
Nose cone: 2.3"

Total length: 19.52"

A couple thoughts about attaching the boosters:
- The process that was very well delineated in the article I posted earlier would be a nice fit here. however, I wonder if I could get away from only using 1 prong (dowel) rather than 2 per booster. I don't see a reason why it would be unstable
- since i will have 6 boosters that will separate from the BT-55 tube, even spacing will be paramount. would likely create a "dowel ring" around the BT-55 tube that would hold all the launch lugs to insert each booster's dowel into.
- will use BT50 sized nosecones sanded down to the 2.26cm diameter the custom boosters I will be using have and be glued in. would likely use rear eject streamer recovery for each booster; however, when I am building will entertain perhaps a small 6' parachute wrapped around the BT5 engine mount. would be fun to see all 6 boosters float softly down on their own little parachutes

As for the transition piece, i cannot find a bt70 to bt55, but jonrocket does have bt70 to bt60. this can likely be sanded down or dremeled down to size relatively easily. This piece could also be used as a baffle of sorts by putting multiple holes through it. this would also allow air to enter the bt70 tube and deploy the parachute

Glad to help. For this sort of thing, you're touching on areas where custom parts are necessary. Some of them cry out to be 3D printed, but parts like the transition (and the cone) can probably be made pretty cost-effectively by someone like Sandman. I had him make the transition and cone I needed for an upscaled Astron Cobra (3" to AT 1.9" tube). You might talk to him to get what you need. That might be the only way to get a properly shaped nose cone, too. This Semroc cone from eRockets might be close enough for you (in place of the short ogive shape in your first render):


but if you want the actual correct blunted shape, you might have to go custom. I doubt it'll be that expensive.

As for my own version, I'm thinking a little bigger - more of an accurate, stand-off scale, model (i.e. 9 SRBs, near correct proportions and shapes). I don't have time to get into too much detail, but I'll offer that BT101 tubing is almost dead-nuts perfect for 1/40 scale of the 4 meter payload fairing diameter...