Tuesday, August 25, 2015

Saturn V, SA-667 - final touches

Well, it's done. I epoxied the bellmouth onto the lower body with JB Weld and attached the augmenter tube assembly with three small screws. The bottom of the augmenter tube assembly is at the top of the thick black/white striped sections on the base. I cut 1" sections from those black areas to help avoid the Krushnic effect. The upper and lower bodies are connected with 5 basswood spars. I have two 1/4" lugs - one next to a spar and one at the base. I didn't consider lugs when I aligned these sections and, since I wanted the upper lug to be supported by a spar, I had to trim the corner of one of the engine shrouds.

It weighs in at 18.3 oz and the CG is an inch above the air gap. I hesitate to say thiis, but it should be marginally stable without the GDS and thus it should fly fine. I said that about its predecessor so who knows. This will be flown from HPR pads suitable for 'L' motors.


A big V-2 history post (updated with a video)

The images below document a V-2 launch circa 1950. They were part of an article in the October 1950 issue of National Geographic, which was written by Clyde T. Holliday.  Mr. Holliday  was an employee of the Johns Hopkins Applied Physics Lab under contract to the Navy.  Click to see the biggest copies. (The image above documents two V-2 launches circa 2008.)

Update:  The photos below are of round No. 56, launched November 18, 1949.  Along with the pictured camera, it carried a Pirani temperature probe, air sampling bottles  (U. Mich.) and a 'grenade experiment' (Army Signal Corps.).  It reached an altitude of 77 miles. (via ROTW,  Peter Alway,   pp. 21-22.)

Update #2: This NatGeo article is referenced in a article from Air and Space Magazine: The First Photo from Space, Tony Reichhardt, November 2006.

Update #3: Added a video.

Saturday, August 22, 2015

Saturn V, SA-667 craziness

I received the aluminum water bottle whose neck was supposed to form the bellmouth section of my augmenter tube. And, after some hacksaw work, I had a bellmouth. Here it is dry fit to the lower body and the induction tube. At ~$10, that is the most expensive single component. It feeds into a 6" induction tube (38mm BlueTube). That was sized very roughly based on a sketch of a Jetex augmenter. Oh my, this whole hairbrained idea is taking this project to a new level of craziness. The BlueTube is centered in a coupler and will sit below the neck of the bellmouth. That sub-assembly will be attached to the lower body with 4 screws and will be removable. I will be drilling a lot of vent holes in the lower body below the tail end of the induction tube. This isn't Sparta, it is madness!



Wednesday, August 19, 2015

Saturn V, SA-667 building status

I resumed construction of the next-gen Gas Dynamic Stabilized (GDS), aka Induction Stabilized, Saturn V. I had started top down and now continued from the bottom up. Hopefully these sections will meet in the coming weeks. The features shown in the photo includes the 3.1" OD tubing, the bottom most paper wrap, fairings that were attached to and cut from BT-60 tubing and fins that have a core of 1/64" fiberglass. The nozzles are a plastic part that was included in a box-o-parts that I inherited from Paul Miller. I hot glued the nozzle piece to a section of telescoping tubing and it is thus only for display.


I have decided on an inner induction tube inspired by the old Jetex augmenter tubes. These were demonstrated to increase the thrust by up to 30%. Mine will not be optimally shaped so I don't expect any noticeable gain. Heck, I'll just be happy if it stable during boost and is recovered in one piece. I plan to make the bellmouth from an aluminum water bottle. Finding one locally that was both close in size and inexpensive was problematic so I ordered one off of Amazon.  How to  mount it, how to attach an induction tube and how long to make said tube are questions yet to be answered.

Tuesday, August 18, 2015

Rocket recovery rig

After losing a rocket to the trees last weekend, I decided to build one of US Water Rocket's tree rescue system. They described their tool in a video: Tree Rescue System. Mine is basically the same concept but has a smaller PVC tube (3/4"vs. 1" diameter and 2' vs. 3' long). I also fashioned a duct tape pouch to help hold the projectile. They used weighted dowels so I made one of those and also grabbed a scrounged arrow.


I shot the arrow over a low limb in the back yard and it looks like it should work. I need to venture further away to see just how high I can reach. I suspect that, by the next launch, my Saturn V will be in poor shape but I will try to recover it just for practice.

On another note, I would have preferred using a slingbow so I could have used it for target shooting too. However, this was just quicker and easier and less expensive.

Sunday, August 16, 2015

Hostile Projectiles V-2 rebuild complete

Well, you can't find your lost stuff unless you look for it...and I didn't trek up the large hill to search for my lost nose cone.  Here is the new nose cone and new paint job. I didn't go for my usual blotchy camo scheme and I'm not sure I'm 100% happy with it. In any event, it is what it is at least until it is rebuilt again. One thing I like about camo schemes based on Rustoleum paints is that you can shoot all the colors within an hour. Start light to dark and wait about 10-15 minutes between colors.


Saturday, August 15, 2015

Launch Report 2015-7 (NARHAMS)

Location: NARHAMS, Mt. Airy
Weather: sunny, low 90's, wind 0-3?
Total flights: Today - 11; YTD - 53
Total motors: Today - 11; YTD - 57
Motors by class YTD: MMX-2; B-3; C-15; D-4; E-11; F-14; G-7; H-1

Water rocket flights (not included in the totals above): 6

This was as good a day as you are going to get. Not too hot, sunny, barely a breeze and the long grass had been freshly mowed. My wife and dog kept me company to boot. Special thanks to the Ha's for running the launch, Jim Filler for keeping an eye on, and leading us to, my ejected 18/20 case, and Jef Fineran for going out to try to recovery my Saturn V.

My flights:
  1. Estes Sizzler (kit #1906) on a B6-4 - Nice flight, the first in over 17 years.
  2. Quest DC-Y Space Clipper on a D24-4 - Fast boost with a whistle. Late eject, even later 'chute and ejected case. It recovered safely and the case was found. WINNER!
  3. Estes Helio*Copter on a B6-4 - Good flight but it needed rubber bands on the helicopter blades. Ooops.
  4. Art Applewhite Max-Q on an F15-0 -  Nice flight.
  5. 5th Generation on a C11-3 - Nice flight.
  6. Shrox SHX-15 on a C11-3 -  Nice flight.
  7. Estes Majestic on an E16-6 - As this sat in direct sunlight, the cone became VERY tight. Luckily, I checked. I only put it in halfway in, which worked out well.
  8. Estes Mega Mosquito on an F15-4 - Really great flight!
  9. First Flight Mega Sonic on a D12-5 - Good flight, but the balsa cone got another Estes smile. Shock cord is stock length as it was a Beta test build.
  10. Estes Big Dipper Daddy on an E9-4 - Great flight with an award for landing closest to the RSO tent.
  11. Saturn V, SA-666 on an F44-4 - This was actually my first flight so it would go up before the Scouts arrived. The boost started arrow straight and then it took a hard right turn (probably around burnout). With the vents in the transition covered, it had no wobble and didn't ever tumble. However, it landed over 50' up in some trees. RIP.

Tuesday, August 11, 2015

Hostile Projectiles V-2 rebuild, or how to tempt the rocket gods to return the original cone

At the last NARHAMS launch, the Hostile Projectiles V-2 separated and the cone drifted away. I thought I saw it fall on the near side of a far tree line but my wife thought it went over. I started out to find it but the big hill, 4' grass, and the heat got the better of me. I found JonRocket had BT-60 PNCs that would make a suitable replacement so the order went out (5.5" long vs. 5.25").

The order arrived today and the simple rebuild is under way: Cut base off cone, add nose weight with Kevlar leader embedded, and paint/repaint.  Here is the 1st cut at the updated simulation. The mass object near the CP was added to make the body section match the as-built. I then added the nose cone with another mass object to move the CG to the desired spot (same as the original). I takes 2 oz as the resin tail cone is quite heavy. I plan on repainting the whole thing in a camo pattern using tan, orange and OD green. I did this on the latest version of the El Tubo Loco and liked it. Plus, it's 'use what ya' got'.

hostile_projectiles_v2 rebuild
So, what is that 'rocket god' comment all about? Well, I feel that if I go out of my way to quickly restore the rocket, it raised the chances that the grass will be mowed and the old cone is found hanging a few feet off the ground in the trees.