1/5 Scale Nike Hercules

[sambatterman]

Started the avionics bay. So many thoughts here...

First, it will contain 4 altimeters - primary and backups for both forward and aft ejections.
Second, this unit is embedded in the sustainer - it is not removable. It is accessible from hatches on one side of the sustainer.
Third, like many avionics' bays, this has four pieces of 1/4" all thread holding it together. The top and bottom caps are two pieces of 3/8" birch. One is embedded in the tube and the other forms a cap.

I'm working on a diagram to describe for everyone the deployment plan. I'll try to post that this week.

 

[sambatterman]

There are still small canards that sit forward of this fin point on the nosecone. They will go through the nosecone's fiberglass wall and make a nice area in the interior where I can put the recovery hard point and lead shot to pull the CG forward to where it should be. The sim says 10-15 lbs., but I will have to see what it looks like before I do that.

 

[sambatterman]

It would be way cool if OpenRocket could automatically generate diagrams like this. It has all the info it needs to do so. I might recommend this.

 

[David Schwantz]

Do you have a backing plate on the other side of the U bolt also?

 

[sambatterman]

Do you have a backing plate on the other side of the U bolt also?

Yep!!!

 

[sambatterman]

Beginning the second blue tube skin on the sustainer. Blue tube cuts well. Just use a jig saw.

 

[sambatterman]

Working on the hatch for the booster. A thick card stock shaped as a hatch cover and covered with four layers or carbon fiber and fiberglass. We’ll see how it goes…

 

[sambatterman]

Every once in a while, something crazy actually works out. The hatch cover that I layered carbon fiber and fiberglass over thick cardboard stock came out pretty well. There's still some clean up and reinforcement and sanding to do on it. It will be held to the booster with 1/4" T-nuts and screws.

 

[sambatterman]

This weekend I'm working on the blue tube skin that fits over the foam. It's going to make a great surface to finish and a final fillet at the large fin roots should provide all the strength we need to ensure those crazy things stay affixed during flight.

 

[sambatterman]

Hatch on the booster is nearly complete. This crazy thing was a ton of work. I'm also completing the blue tube skin on the sustainer and filling and sanding any edges. Pictures of that coming this week. Let's see, what's left here... Avionics bay, sustainer hatch, electronics sleds, priming the sustainer, BP charge separation test, final painting and decals (thank you StickerShock23.com) and installing recovery drogues and chutes.

 

[sambatterman]

Weigh in number two! Booster is 35 pounds, sustainer is 23 pounds, nosecone is 12 pounds. With motor (L2200) at 10 pounds it will be around 80 pounds. Still have electronics, shock cords and parachutes/drogues to work in and paint. With L2200 delivering 488 pounds of thrust and the 5:1 ratio, I need to stay under 97 pounds.

 

[fyrwrxz]

OMG! Dude, I can totally appreciate all the engineering difficulties you have conquered. Mind you, I'm a retired aerospace engineer, so it's not faint praise. Really looking forward to flite pics! Straight smoke and good chutes!

 

[jmasterj]

Weigh in number two! Booster is 35 pounds, sustainer is 23 pounds, nosecone is 12 pounds. With motor (L2200) at 10 pounds it will be around 80 pounds. Still have electronics, shock cords and parachutes/drogues to work in and paint. With L2200 delivering 488 pounds of thrust and the 5:1 ratio, I need to stay under 97 pounds.

Per our discussion in your L1 thread, make sure you look at the rail speed for this beast. That L2200 is justly barely acceptable for a 75lb (dry) rocket with 6 feet of rail guidance to work with. You might have longer rails available, but remember that only the length above the top rail button really counts.

 

[sambatterman]

Per our discussion in your L1 thread, make sure you look at the rail speed for this beast. That L2200 is justly barely acceptable for a 75lb (dry) rocket with 6 feet of rail guidance to work with. You might have longer rails available, but remember that only the length above the top rail button really counts.

It's UNISTRUT rail buttons --- and I know that Dan Michaels flies off of larger rails at MDRA...I was just thinking about that conversation this morning. The top rail button is at the top of the booster (around 38" tall). I'll send a message to the MDRA leadership and find out the tallest Unistrut rails they have available.

 

[jmasterj]

It's UNISTRUT rail buttons --- and I know that Dan Michaels flies off of larger rails at MDRA...I was just thinking about that conversation this morning. The top rail button is at the top of the booster (around 38" tall). I'll send a message to the MDRA leadership and find out the tallest Unistrut rails they have available.

You should be good, then. Those rails are probably 12-15ft tall.

 

[sambatterman]

Still working on the sustainer Blue Tube skin. It’s now filled with Super Fill and ready for a final sanding and ply of fiberglass.

 

[sambatterman]

Sustainer is now fiber glassed. Super happy with the result.

 

[lowga]

Really starting to take shape now. Can't wait to see the finished rocket. One of the best build threads on TRF in some time. Thank you for sharing.

 

[dbpeirce]

And the filling begins!!!!!!
Looking great!

 

[sambatterman]

I figured I would show a quarter of the sustainer blue tube being fiber glassed. I used a single sheet roughly cut to length. Wetted out the tube with West Systems (I've used 3 gallons of the stuff over the last 6 months) tip to tail and smoothed the glass onto the tube. Then I ran a brush with some light epoxy over the edge/fin root. After 30 minutes when the glass goes into leather stage, I cut the excess off with an xacto-knife.

 

[sambatterman]

Started working on the deployment sled for the sustainer. Redundant altimeters for forward charge (separating the nose cone from the sustainer) and the backward charge (separating the booster from the sustainer). Two Missileworks RRC3s and two PerfectFlites. I can't wait to show you how this card will slide into the avionics bay! It's quite a different approach, since the sustainer uses hatches to access the BP charge areas and the avionics bay, which is glued into the sustainer and not removable.

 

[sambatterman]

Okay - now you guys are going to think I've gone completely crazy. This is the avionics bay. It's a 6" ruby fiberglass coupler that is caped with 3/4" plywood discs that form a cap with an inner lip. All thread runs between the discs and doubles as lateral strength and the rail to hold the avionics sled. You might ask "why is a quarter cut away?" Good question - and something I have deliberated about for months. This coupler is not removable, it will be glued into the sustainer. The sustainer does not lend itself to breaking apart as you would normally handle something like this. So, we are left with a hatch approach. Hatches in this case are complicated because it's not just one hatch. You need to be able to get to the hard point to connect the chute, set the BP charge, thread the igniters, etc. It also needs to be sealed so the BP pressure blows the nose cone and the booster from the back.


Looking deeper into the assembly you can see the bottom 1/4" all thread. That all thread will carry a base plate that will allow for a perpendicular avionics sled to slide onto it easily and be removed and assembled easily.



Here's a better view with the base plate dry fitted. The vertical 1/4" all thread is where the avionics card will slide down onto. More on that in tomorrow's post.



A side view showing the base plate and all thread holes that will position the board so that the avionics board is always perpendicular with easy access from the hatch.



Let me know your thoughts. I'm very aware that this is avante garde for avionics bays.

 

[sambatterman]

I also got the Unistrut rail buttons put on and tested with an 6'-foot section of Unistrut rail. Works great. The booster is ready for one more priming and then final paint and decals.

 

[sambatterman]

Working on the hatches for access to the avionics bay and BP charges and hardpoints. I hate hatches. They are a ton of work.

 

[sambatterman]

Here’s the avionics bay assembled. I’m working on the card that will slide in right now. While it’s unusual, it will get the job done.

Here’s a prototype of the avionics card. I’m working on mounting the electronics and routing the wiring.

 

[sambatterman]

The altimeters are mounted on the card.

 

[JackC]

Did your motors show up? I want to see your Nike fly at NXRS!

 

[sambatterman]

Did your motors show up? I want to see your Nike fly at NXRS!

Hi Jack - I live in PA, so getting to Oregon (I think that's where NXRS is) would be a haul. I'm planning on flying at MDRA in either July or August this summer - most likely August at this point. I will make sure I have a dozen cameras trained on the launch so you feel like you were there.

 

[JackC]

Hi Jack - I live in PA, so getting to Oregon (I think that's where NXRS is) would be a haul. I'm planning on flying at MDRA in either July or August this summer - most likely August at this point. I will make sure I have a dozen cameras trained on the launch so you feel like you were there.

Sorry, I don’t know why I thought you were in the Pacific Northwest. I will love to see the photos. Good luck!

 

[sambatterman]

Nosecone is almost done.