1/40 Delta III

[stevem]

that must be exactly what happened - great idea vjp - thank you.

 

[marvSRG]

Great job! Sorry about the loss, but good luck on the rebuild--that thing is a beauty!

 

[mike_bar]

Originally posted by stevem
My son and I just kinda stood there for a moment and then started laughing. What else ya gonna do?

I will rebuild this one and try again

Sorry about the mishap, the model looked beautiful, as always.

Originally posted by stevem
here's a pic of the nc - I am very happy with how this turned out for my first attempt at a cardstock nc. I used the same technique on the boosters - cones are all made of cardstock with a 5/16" wooden bead for the tip.

I am going to make some clear fins for this thing - where do you guys get the clear plastic to make fins out of?

Since you will be rebuilding, I had two questions:

1. What material did you end up using for clear fins? Did you go with Lexan? What thickness? How did you attach the fins to the sustainer?

2. That nose cone is beautiful. Can you describe the construction in more detail? Did you use centering rings inboard or only at the base? What is a "wooden bead" nose cone tip? Did you make a cardstock “transition” with a stubby balsa cone tip?

Thanks in advance for the prior build thread. I am most interested, and love your work.

Regards,
Mike

 

[stevem]

Thanks Mike - here ya go

1. What material did you end up using for clear fins? Did you go with Lexan? What thickness? How did you attach the fins to the sustainer?

I used a piece of 3/32" acrylic that I got at Lowe's. Not sure if it's Lexan or not. Basically Lowe's had two types of clear plastic material. One type was much more expensive than the other. I used the cheaper of the two. Sorry I don't know exactly what it was. To glue it to the rocket I drilled a series of 1/16" holes along the BT where the fins attach. Then I drilled a series of 1/16" holes al along the root edge of the fin abot 1/16" of an incn from the edge. I then used 5 minute epoxy mixed with cab-o-sil for added strength. It made a very strong joint. As you can see in my 'exploded parts' picture, two of the fins remained solidly attached after the impact!

2. That nose cone is beautiful. Can you describe the construction in more detail? Did you use centering rings inboard or only at the base? What is a "wooden bead" nose cone tip? Did you make a cardstock “transition” with a stubby balsa cone tip?

Maybe this diagram will help explain how I made it. I made the shroud first using VCP. Then I got a styrofoam craft ball that was as close to the scale diameter as I could find. A 2" ball was close. I sanded it carefully to maintain the roundness and then glued it into the shroud fron the inside. Then I added the centering ring. I then slid the length of BT80 coupling material up into through the CR until it made contact with the insode of the shroud. I glued this all in place. Then I glued a balsa block (bulhead) into the BT80 coupler. Once it was all glued up I coated the entire thing with 3 coats of finishing epoxy using a rotisserie motor to rotate the cone while the epoxy cured. I then filled all the low spots using Bondo Spot glazing putty.

For the rebuild I am considering an all balsa nose cone. I haven't decided yet. I had to add 4 ozs of clay to the front of the rocket since the nose cone was so light. With an all balsa cone I shouldn't need to add any weight.

I will not use a 24mm stuffer tube to run up into the chute compartment this time. Since BT80 runs length of the rocket (it goes up through the upper 4" section) I will just put a baffle in and that's it. I think this give more reliable ejection.

 

[stevem]

here's a rough diagram of the original build

 

[stevem]

this is how I am leaning on the rebuild

 

[mike_bar]

Originally posted by stevem
I used a piece of 3/32" acrylic that I got at Lowe's. Not sure if it's Lexan or not. Basically Lowe's had two types of clear plastic material. One type was much more expensive than the other. I used the cheaper of the two. Sorry I don't know exactly what it was. To glue it to the rocket I drilled a series of 1/16" holes along the BT where the fins attach. Then I drilled a series of 1/16" holes al along the root edge of the fin abot 1/16" of an incn from the edge. I then used 5 minute epoxy mixed with cab-o-sil for added strength. It made a very strong joint. As you can see in my 'exploded parts' picture, two of the fins remained solidly attached after the impact!

Steve,
Very nice fins. I suspect the more expensive clear plastic was Lexan.

Lexan is reported to be much stronger than acrylic. Acrylic fins tend to snap-off at landing. It is impressive that your acrylic fins held-up on this Delta landing, but they did not take a direct hit. That looks like an excellent technique for the fin attachment.

Thank you for the detailed construction notes.

 

[mike_bar]

Originally posted by stevem
Maybe this diagram will help explain how I made it. [Snip]

Excellent diagram of a fine construction technique.

Originally posted by stevem
For the rebuild I am considering an all balsa nose cone. I haven't decided yet. I had to add 4 ozs of clay to the front of the rocket since the nose cone was so light. With an all balsa cone I shouldn't need to add any weight.

I have worked with paper components often. I agree with you, the parts come-out light weight.

I understand how you would consider a balsa cone. I would do more balsa cones if I had wood lathe. In the meantime, I will continue with the paper cones. I will most likely beef them up with more centering rings, and use more laminated parts to add strength and weight both.

 

[stevem]

Here's the first stage of the rebuild - I've reused the plywood centering rings from the first model and have installed the 4" BT and the shrouds for the nose cone and the lower transition.

Thankfully the 9 booster assemblies survived the crash so I don't have to remake them all.

Next step is to make the top of the nose cone out of balsa.

 

[dlrflyer]

Cooool rocket, too bad about the lawn dart. I'm still looking at the pic showing the business end. How did you manage to wire up the ignitors? Whatever technique you used obviously worked well.

 

[stevem]

How did you manage to wire up the ignitors? Whatever technique you used obviously worked well.

it did work very well - its nothing fancy, I made a 6 pair clip-whip and connected like this....

I use a 12volt battery and a relay type launch system. This is the biggest cluster I have done to date and all the motors lit!

 

[Delta-IV]

Steve,

I just joined the group a couple of weeks ago and am doing a Delta IV. I actually work here at the Cape.

If I was you I would scrap the Delta III thing. We did so here on the real things. Its Delta II's or IV's. The Delta IVs come in 5 configurations. See Attached...

Good job on the model it looked very impressive.

I will attached a small photo of my prototype D-IV Medium 4+2 on next reply.

 

[Delta-IV]

Attached is the D-IV Medium 4+2 just prior to its 2nd launch. Complete 3 so far, next launch will be powered strap ons (captive).

 

[cjl]

I don't see why he should scratch it just because it is out of use in real life. Heck, one of the most popular scale projects among rocketeers is a Nike Smoke, and that hasn't been used in a much longer time than the Delta III has been out of use.

 

[Delta-IV]

I was just kidding, a little pun considering his launch attempt. As he said, he and his son just laughed after a moment of silence. The Delta III (real one) was kinda just like that too. A good idea that just didn't work out this time.

I too have had a few of those, I remember a Little Joe II that I didn't install the ballast weight that chased my Dad for a couple of loops. He never went to another of my launches....can't figure???

 

[stevem]

Scrap the Delta III!!???

no way! this is one of my favorite rockets!

here's a picture of my rebuild progress....

 

[stevem]

Delta-IV - nice to know we have a Delta expert on board!!

good looking model you have there! You say the strap-ons are captive - any thoughts on making them separate? I love stuff that comes off my rockets as long as it is SUPPOSED to come off!

Did you ever get to see any of the Delta IIIs launch??

I don't know much about them other than they make a cool model!

I'm thinking about putting a 29mm central MMT in this rebuild for more engine options. That way I can adapt down for the central 24mm when I want to cluster or I can fly on a single 29mm.

Its either that or I will figure out a way to use my interchangeable MMTs which will give me the option of flying on a single 29mm or even a 13 x 24mm cluster!!

 

[Delta-IV]

SteveM,

I wasn't here for the Delta III's, some of my co-workers remember the doom and gloom after the first one blew up and the second one didn't get a second stage burn. The third and last flight was a success, but by then the decision was made to press with the Delta IV. Many things on the D-IV were developed on D-III though.

Go to this link if you haven't already.....

https://www.boeing.com/defense-space/space/delta/delta3/delta3.htm

I am building a prototype D-IV Heavy, yes I plan to jettison the outboard Common Booster Cores. I plan to have a complete suite of >36 inch tall Delta IVs with even the Solid Rocket Motors (SRM) being jettisoned.

The Boeing website offers excellent data to do a fairly good scale job. For me I do have that inside edge.

 

[brianc]

Originally posted by Delta-IV
Attached is the D-IV Medium 4+2 just prior to its 2nd launch. Complete 3 so far, next launch will be powered strap ons (captive).

We interrupt this thread.....

Delta-IV, check your PMs.











And now back to the excellent discussion and pics of "Boeing Builds"...

 

[stevem]

I'm hoping one of you guys can help me with this.

on the real Delta III, what is the yellow/gold colored wrap approx mid-way on the large upper airframe?

I know its some kind of insulation for the cryogenic rocket engine but what type of material is it?
Is it a shiny gold? does it have some kind of texture?

One the original build I just enlarged the wrap from a set of paper plans and printed it on a color printer. Looked OK but it always looked like a paper wrap.

Thanks!
Steve

 

[Delta-IV]

Its insulating foam...the same stuff on the Shuttle ET. On Delta IV, the same stage (Upper Stage) is painted, but on Delta III it was left unpainted.

 

[stevem]

thanks Delta IV

here's the rebuild progress picture with the rocket painted and the insulating foam wrap applied.

 

[Delta-IV]

Looks excellent, just like the real thing!

Great Job.

 

[stevem]

booster attached and some detail added...

decals will be next