1/10 Sport-Scale Nike Hercules

[pugachu]

Ever since I saw Wedge's 1/3 scale Nike Hercules a long time ago, I've wanted to build one. Back then, 3d printers and CNC routers weren't hobbyist tools, so it was a huge challenge.

Fast forward to now, and actually making a sport scale (not exact) is doable for me without a crazy amount of difficulty.

Attached is a basic CAD rendering of my plan. It is approx 1/10 scale, with a 3.1" OD sustainer, and the booster tubes are made from 54mm tubing.

The booster will be a central 38mm, surrounded by 4x 29mm mounts. The sustainer will be a single 54mm.

I've done HPR clusters, airstarts, and staging, but not all three on the same rocket.

 

[pugachu]

Our local field is small, with a low waiver, so I can't fly this 'full send' anytime soon. Initial simulations show this as going over 10k with a mild I and 4 G's in the booster, staging to a J in the sustainer.

The max motor that I can fit in the sustainer is a 3-grain J, but I can only do that if I can put enough nose weight in to keep it stable. In reality, I probably won't put anything bigger than a 38mm full I in the top.

I plan on flying the sustainer single-stage first, to prove out stability, keep it low, and test the recovery. There is very little room for a proper sized parachute, with all of the nose weight that I anticipate needing.

 

[pugachu]

So far, I have printed the centering 'rings' for the booster, and attached the motor mount tubes. The plan is to use two part foam to fill and support the structure. I am still debating how I will attach the booster fins, as there isn't a lot of 'through the wall' support. Having the 29mm mounts in the booster tubes gives me less than 1/4" long 'tabs' for the fins that go through the wall.


While I figure the fin attachment out, I have focused my work on the sustainer.

I have printed the sustainer nosecone, cut the 54mm core body tube, made the aluminum nose tip, and cut out the nose fins. I have a 'dry fit' of the nose shown below

The main structure tube is a failed attempt at vacuum bagging a fiberglass airframe. It wrinkled horribly, but it will be fully covered in this build, so I decided to use it here.



The next steps will be beveling and attaching the nose fins, and filling the nose with steel shot and epoxy. I plan on filling it in as much volume as I can, while leaving a 6" section of 38mm tubing empty for the recovery and staging electronics. I plan on machining removable weights to slip in the top of the electronics bay, to allow me to dial in the ideal stability.

I also need to print the tailcone, and cut the main fins from 3/16" plywood. I'm hoping to have the tailcone and main fins ready for attachment this weekend.

It's actually a little smaller than I imagined, but it's not a bad size.

 

[astronguy]

Attached is a basic CAD rendering of my plan. It is approx 1/10 scale, with a 3.1" OD sustainer, and the booster tubes are made from 54mm tubing.

The booster will be a central 38mm, surrounded by 4x 29mm mounts. The sustainer will be a single 54mm.

A Nike M-5 Booster is 16.44" in diameter, so a 1/10 scale model would be 1.644" dia - BT-60. The 54mm tube is 2,26" diameter, making it 1/7.27 scale, 28% bigger. Recheck your numbers.

Brian

 

[pugachu]

A Nike M-5 Booster is 16.44" in diameter, so a 1/10 scale model would be 1.644" dia - BT-60. The 54mm tube is 2,26" diameter, making it 1/7.27 scale, 28% bigger. Recheck your numbers.

Brian

The sustainer is 3.1" OD, which is about 1/10 scale, the booster is closer to 1/8 scale, as you indicated. I do agree that this is not a perfect scale model, and that is why I called it a sport scale in the title and description. I will not be trying to achieve a perfect scale representation, that was never my intent to make this a museum or contest model. it is just for fun. I went with a bigger OD in the booster to allow room for recovery electronics and the parachute. there isn't a lot of room for that with 1.6" body tubes.

 

[terryg]

How are you going you to do the interstage? I would think that would be tricky to build. I love Nike Hercs!

 

[pugachu]

How are you going you to do the interstage? I would think that would be tricky to build. I love Nike Hercs!

Hi Terry,

The current plan for the interstage is 4x 1/4" fiberglass rods that feed into holes in the tailcone:



Again, the intention of this was not to be an exact representation, but a sport scale loosely based off of the Nike Hercules

 

[terryg]

Cool, years ago I made a funscale Nike Herc. It had four 13 mm tubes and a hand carved epoxy coated transition to the sustainer. Flew it with four A10 engines. It will be interesting to see how the 3d printed parts hold up to the heat from the engines.

 

[ReynoldsSlumber]

Cool, years ago I made a funscale Nike Herc. It had four 13 mm tubes and a hand carved epoxy coated transition to the sustainer. Flew it with four A10 engines.

That pencils out to a C with a peak thrust of 39 Newtons, or almost 9 pounds! Impressed that a "minimum diameter" model like that held up.

 

[astronguy]

The sustainer is 3.1" OD, which is about 1/10 scale, the booster is closer to 1/8 scale, as you indicated. I do agree that this is not a perfect scale model, and that is why I called it a sport scale in the title and description. I will not be trying to achieve a perfect scale representation, that was never my intent to make this a museum or contest model. it is just for fun. I went with a bigger OD in the booster to allow room for recovery electronics and the parachute. there isn't a lot of room for that with 1.6" body tubes.

I'm more concerned with the CP shifting around. That's a lot of forward fin area.

Brian

 

[beeblebrox]

So far, I have printed the centering 'rings' for the booster, and attached the motor mount tubes. The plan is to use two part foam to fill and support the structure. I am still debating how I will attach the booster fins, as there isn't a lot of 'through the wall' support. Having the 29mm mounts in the booster tubes gives me less than 1/4" long 'tabs' for the fins that go through the wall.
View attachment 644326

While I figure the fin attachment out, I have focused my work on the sustainer.

Suggestion if it is not too late... Move all the outer motor mount tubes inward towards the central tube, this will give a larger amount of fin tab length thru the outer wall of the 4 Nike tubes. Since you are printing them, they don't need to be concentric...

 

[Cannonball]

It is looking good. Since it ia sport scale model, you would be doing yourself favor by slightly increasing the booster fin span and slightly decreasing the sustainer span. You can play with the dimensions in open rocket to see how much less nose weight you will need.

I just finished a 30" Herc close to scale/ I was in a hurry to get out to the dessert with my son and grandson this season before the heat hit and used approximate cg/cm measurements from other models. I used a b55 single center tube through the entire rocket with a b60 around it for the sustainer and b50 tubes laser cut lengthwise to fit tight the center tube for the booster. used a single E9. Rocket was 10 oz ready to fly minus motor. It went unstable at about 60 ft but lived. I came home and downloaded Open Rocket and keyed in the dimensions and it says my CG configuration was only .6 stable. I can add nose weight but it is already on the heavy side. I love the Herc and will build another. This one sill use a 4 engine cluster and possible a second stage.

 

[pugachu]

Cannonball, I like your launch rail and nike-herc!

The booster on mine is closer to 1/8 scale, so the fins are much larger than the sustainer, and I currently have no stability issues when it is in the two stage configuration. the nose weight is really for the second stage, where it is marginal, due to the nose fins, and main fins that are the whole length of the second stage. if I reduce the span on the sustainer, it will make it even less stable.

I got some more work done on the rocket this weekend, and will take pictures later today. it was a pretty busy weekend.

 

[Cannonball]

Pugachu, that makes sense. I look forward to more pics and updates.

Thanks, I put together the launch pad last minute 2 days before launch. I wanted to use a launch rail system, but the extra shipping cost attached to a 10/10 rail caused me to procrastinate the order. I ripped 1/8"3/4 x 3/4 aluminum angle to 1/4 x 5/8 for {2} 4' rails and attached to a 1-inch strip of 3/4" marine ply and smoothed with a file. It worked but was ugly so I laser cut rail box from 1/4 ply for looks. I was going to mount it to the top of a camera tripod but didn't trust the tripod to hold the weight of the rail assembly, (and it made the rocket look small.) So a couple of days before launch I drew and cut out the pad from mostly 1/4" ply. I made pvc extension legs front and back and a shelf for steel weights in the box underneath. I was pretty stable with just the weights and tear legs.

 

[pugachu]

Cannonball, I just noticed you are new to the forums, welcome!

I used to live near LA, and I was able to drive to McMaster to pick up the 1010 rail to avoid shipping. It does cost about as much to ship it, as it's worth, if you're only buying one stick.

 

[pugachu]

I attached the 4 booster fins to the outboard motor mounts. The plan is to put a strip of fiberglass at the root, then fill with two-part expanding foam, then fiberglass them to the outer tubes.

I also attached the first big fin to the upper stage, and started attaching the spacers and transition guides.


I beveled the nose fins, epoxied them in, filled the tip with steel shot+epoxy, and put the all thread in, along with the electronics 'sled'.

 

[terryg]

It is looking good. Since it ia sport scale model, you would be doing yourself favor by slightly increasing the booster fin span and slightly decreasing the sustainer span. You can play with the dimensions in open rocket to see how much less nose weight you will need.

I just finished a 30" Herc close to scale/ I was in a hurry to get out to the dessert with my son and grandson this season before the heat hit and used approximate cg/cm measurements from other models. I used a b55 single center tube through the entire rocket with a b60 around it for the sustainer and b50 tubes laser cut lengthwise to fit tight the center tube for the booster. used a single E9. Rocket was 10 oz ready to fly minus motor. It went unstable at about 60 ft but lived. I came home and downloaded Open Rocket and keyed in the dimensions and it says my CG configuration was only .6 stable. I can add nose weight but it is already on the heavy side. I love the Herc and will build another. This one sill use a 4 engine cluster and possible a second stage.

Since it survived, add more nose weight and fly it with a Q-Jet E35W!

 

[terryg]

Looking good! Looking forward to seeing it fly.

 

[pugachu]

Looking good! Looking forward to seeing it fly.

Thanks, Terry.

it probably won't fly until this fall, as it's starting to get stupid hot in the desert, and I don't want the 3d printed parts to get soft and start creeping. Plus, I gotta wait until Mark at Sticker Shock gets better, so he can make stickers for this rocket

 

[pugachu]

Did a little work on it the last few days. I printed a shelled out tailcone, to save resin and weight. The current plan is to fill in the remaining with a thick paste of microballoons and west systems epoxy, then sand to final shape.

 

[terryg]

I gotta wait until Mark at Sticker Shock gets better, so he can make stickers for this rocket

Mark is currently taking orders.

 

[Cannonball]

Cannonball, I just noticed you are new to the forums, welcome!

I used to live near LA, and I was able to drive to McMaster to pick up the 1010 rail to avoid shipping. It does cost about as much to ship it, as it's worth, if you're only buying one stick.

Thanks, I just got back into rocketry and my son told me about this amazing resource. I started low power in 77 but went deep into R/C plane building instead of high-power rockets. 23 Years later I took the same path of rockets to RC planes with my son. Now another 24 years and retired, my son and I are jumping back in with my grandson. I may go into high power this time; I can't see well enough to fly RC and just love building.

I will most likely order a 1010 rail if I go bigger. I probably spent more testing different spray paints for this rocket than a rail would cost delivered, I was just being a stubborn OG spoiled by Amazon free shipping-LOL!

The 3D printer must be handy!

 

[pugachu]

Finished Attaching the main fins, and am starting to attach the small, back fins.

I also cut out the rear electronics bay bulkhead, and attached the forged eye nut


Also, ordered my stickers from Sticker Shock. It'll be a bit before I'm ready to finish this all up

 

[pugachu]

Thanks, I just got back into rocketry and my son told me about this amazing resource. I started low power in 77 but went deep into R/C plane building instead of high-power rockets. 23 Years later I took the same path of rockets to RC planes with my son. Now another 24 years and retired, my son and I are jumping back in with my grandson. I may go into high power this time; I can't see well enough to fly RC and just love building.

I will most likely order a 1010 rail if I go bigger. I probably spent more testing different spray paints for this rocket than a rail would cost delivered, I was just being a stubborn OG spoiled by Amazon free shipping-LOL!

The 3D printer must be handy!

I always wanted to get into R/C planes, but I was too scared of crashing them. I like doing rockets with my kids, and they seem to enjoy it. Hope your grandson gets a kick out of flying them.