Wild Thing Vintage Kit Build Update 3

Here is a brief update on the Wild Thing.  I’ve got the baffle almost finished.  I drilled 4 holes on four sides of the top of the motor tube.  I have the bottom bulkhead of the baffle tacked in place.


Here are all the parts of the baffle section.


I did away with the forward bulkhead that came with the kit and replaced it with two thinner bulkheads from Apogee Components.  I drilled four 1 inch holes in one of the bulkheads.  That will be the top of the baffle.  It will be installed after the motor mount is expoxied in the main tube.  That will let me get a good bond on the bottom bulkhead of the baffle.  The part with the eyebolt in the lower left of the picture is the recovery system anchor point.  It is a 5/8 in plywood plug with a hole in the middle to allow the eyebolt to be attached.  I will epoxy the nut of the eyebolt to prevent any future loosening.  It gets installed at the top of the motor tube.  It will force the exhaust gasses out the holes in the motor tube and then they will pass through the four holes in the forward baffle bulkhead.  I use this system in my Mini Magg to good effect.

Here are the baffle parts dry fitted for a check.


I have also started printing some additional parts for the rocket.  You might recognize what these are supposed to represent.  They are strictly decorative on this rocket.  But I think they will add to the visual appeal once the paint goes on.

That’s it for now, more to come.

Thanks for looking.

Wild Thing Vintage Kit Build Update 2

Time for a quick update on the Wild Thing.  I finished sanding the seam on the tube and it is now quite smooth as can be seen in the below photo.


I did have a spot on one end of the tube where one layer of the fiberglass lamination did not stick and got sanded off. The first layer was still well attached to the tube so I just needed to patch the one layer.  I mixed some 30 minute epoxy and spread it into the divot.  Then I took a strip of blue painters tape to get the epoxy to lay smooth and avoid a bunch of sanding.  After it set I removed the tape.  I gave it a day to completely cure and then sanded it smooth.  The below picture shows the edge where the patch is.  You can hardly tell it is there.


With the tube done for now, I turned my attention back to the motor mount.  I dry assembled the parts and then put the fins in place.  I wanted to see if my tape spacer at the end of the 29mm tubes was going to affect how the fins fit in place.  Here is a picture of the dry assembly.


It looks like they will fit fine.  Without the tape spacer the 29mm tubes would be too close together to get the fins all the way to the 38mm tube.  This is the way the kit was designed.  The result would make the fins just a bit more fragile on landings.  With the spacer in place I am able to get the fins all the way to the 38mm tube.  This will result in a much stronger joint.  I ran the change through Rocksim and it doesn’t affect the stability.  With seven fins it will be very stable even with the fins being about 3/8 to 1/2 inch shorter than the original design.

Next I wanted to start assembling the motor mount.  Since the 29mm tubes actually hold the 38mm tube in place it was going to be very messy trying to glue the tubes together tube by tube and keep them parallel to the center line while keeping the centering rings perpendicular to the center line.  Here is a shot of the plans showing the way the tubes fit together.


What I decided to do was to fit all the tubes together, then get the centering rings lined up and make sure the tubes are not angled.  Then I applied some CA glue to the centering rings and 29mm tubes to hold them in place.  Then I mixed up some 30 minute epoxy and glued the 29mm tubes to the upper centering ring.


After that had cured I used more 30 minute epoxy to glue the 38mm tube to the 29mm tubes from the top of the upper centering ring.


When this is completed I’ll epoxy the 29mm tubes to the back centering ring.  The 38mm tube will be firmly attached to the airframe not only at this point, but also at it’s upper end by the baffle that I will build later.  At the business end, the fins will solidly attach the 38mm tube to both the fins and the 29mm tubes.

When I finish the fins, I’ll work on the baffle at the front of the 38mm motor tube.

Much more to come.  Thanks for looking.

Wild Thing Vintage Kit Build Update 1

I got the new pumps from West Marine, so now it’s time to glass the tube.  I placed the tube on a section of PVC pipe and suspended that between a couple of saw horses.


Next I mixed up some epoxy and coated the tube with the epoxy resin before I started applying the fiberglass.


Next I took my fiberglass and laid one edge on the line I had previously drawn.  Then I slowly pressed the glass into the wet tube and started rolling the tube and applying the fiberglass.  After I had about 4 inches or so started on the tube I then brushed some more epoxy resin on the glass to get it thoroughly wet. When the fiberglass is clear and you can see the tube underneath then it is wet enough.  But you don’t want the resin dripping off either, just enough to get it wet.  I then rolled the tube and applied more glass.  I smoothed it down and toward the tube ends with my hands as I applied the glass.  I also was checking for air pockets in the glass as I was going and smoothed them out as I went.  This continued until I made it back around to where I started and then continued with more resin and more rolling the tube.  I cut the fiberglass so I had enough to wrap the tube twice.  Two layers should be enough for this build.  I’m sorry I don’t have pictures of the actual process, I was doing this by myself and my gloved hands were sticky with resin so I didn’t want to touch my phone.  Anyway here is the tube after it had two layers of glass applied.


I wrapped the ends with some masking tape to try and keep the ends attached to the tube.  Keeping the ends smooth without any wrinkles is one of the hard parts of glassing a tube.  When the fiberglass is at the just barely tacky stage but not fully cured then you can remove the tape.  When the fiberglass is still at the plastic stage but not hard cured you can cut the ends of the fiberglass cloth flush with the tube ends.  Here is the tube with the ends cut off.


You can see I brought it into the house.  I did that to help with the cure.  When the tube was cured to the point that the resin was not wanting to run anymore I brought it in.  The weather just didn’t warm the garage up enough.  The warmth of the house finished the cure nicely.  Next comes the fun part of sanding the seam smooth and doing any necessary touch ups on the ends.  Anyway that’s where is stands as of now.  More to come and thanks for looking.

Wild Thing Vintage Kit Build

I haven’t worked on any flying rockets lately, and with the possibility that I might be able to get vaccinated in the next few months, I thought I should work on a new high power rocket.  I went through my collection of kits and picked an old kit that I bought from a fellow club member many years ago.  It’s a kit by Vaughn Brothers Rocketry.  They started in the mid to late 1990’s and folded sometime in the early 2000’s.

It is an interesting design.  It has a central 38mm motor tube surrounded by seven 29mm motor tubes.  It is designed to be flown on the single 38mm motor or a cluster of 29mm motors or both.  The thoughts of flying a cluster intrigued me.  But with safety considerations, it seemed that the safest way to fly the cluster would be to airstart the 29mm motors after the 38mm got it into the air. But, these days you really need a controller that can sense tilt so you don’t start the outboard motors if you are not near vertical.  Plus, the 29mm motor tubes are mounted flush to the 38mm motor tube.  That leaves little room for positive motor retention.  I’ve pondered those problems on and off for a couple of years, and I have finally decided that I just don’t want the complexity and multiple points of failure beyond what a normal rocket has.

This left me with what to do about the outer tubes.  Enter my new 3D printer.  I have designed a false rocket nozzle that will fit in the 29mm tube and surround and hide the central 38mm Slimline motor retainer.  I’ll print 7 copies of that and install them in the rocket.  That should give the rocket a nice interesting look and solve the cluster ignition problem.

So with that major problem out of the way, on to the build.

Here are the parts in the kit.

Mike, the club member that sold me the kit, had already peeled the main body tube and he even threw in the fiberglass for it.  Here is a close up of the centering rings for the motor mounts.  You can see how all the tubes are going to be very close together.

To get a small amount of clearance for the fake nozzles, I wrapped the end of the 38mm motor tube with some masking tape.  That will move the 29mm tubes out enough to clear the Slimline retainer that I’ll be using on the 38mm tube.

With that done, I started putting the tubes in the centering rings.

I’ve done this a couple of times before when trying to solve the above mentioned problems.  The rings need to be kept in a good alignment to get all the tubes in.

Here is a closeup of one of the fake rocket nozzles.

With the tubes in place (nothing is glued yet) I put the Slimline and a nozzle in place to check for clearances.

Just enough room.  The centering rings need some sanding to fit nicely into the main body tube.  I’ll do that after I glass the main tube.  Before I do that, I need to sand the tube to get the major fuzzies off (you can never get all the fuzz off).  I then applied some CA glue to the ends to harden them and also to repair a couple of minor dents on the ends.

Now I need to actually glass the tubes.  First I need to get over to West Marine to get some new pumps for my resin and hardener.  The pump in the resin can seems to be permanently attached now and the hardener is a black orange color so it appears to be past its prime.  The cans didn’t have much left in them anyway and it has been about 5 years since I last used them.  I have trimmed the fiberglass and marked a start line down the main tube, so I’m ready whenever I get the pumps and have some time.

I’m also working on a new plastic model (a BanDai 1/72 scale X-Wing), so I’m dividing my time between this project and the X-Wing (and whatever life decides to throw my way).  More to come.  Thanks for looking.

LDRS 38 Club Project

LDRS is an annual gathering for high power rocketeers from all over the country and a few from foreign countries as well.  This year was LDRS 38 hosted by the Kloudbusters of Wichita Kansas.  They are one of the best clubs in the country for large launches.  They have hosted several LDRS launches and have it down to a fine art.  Which is good because this was the largest LDRS ever.

At the last LDRS held at the Rocket Pasture, LDRS 30, the club built a two stage scale version of the Nike Asp sounding rocket.  It flew well until time to ignite the second stage.  It didn’t ignite!  The recovery system worked properly and we got all the pieces back.  We vowed that the next time LDRS was here we’d try again.

That time came last week at LDRS 38.  Members pitched in and prepared the motors loaded them into the Nike booster and the Asp second stage.  Electronics were prepared and all recovery devices were packed and loaded into their respective stages.

Then we departed for the away pads and to get approval of the Range Safety Officer to fly.  One small problem getting RSO approval, he didn’t like our electronics set up to assure that the second stage would light only if the rocket was still within a few degrees of vertical.  We worked that one out.  Bob Brown the LDRS leader took one of our members back to our camp site to get the laptop so we could reprogram the electronics.  After a few minutes all was well and we headed out to the pad to get the rocket loaded for launch.  Time was ticking down as our FAA waiver only had about 20 minutes left.  We finally got it loaded with just a few minutes left.

The countdown proceeded well and then with a loud roar off she went.  Staging looked beautiful just like last time.  Then the Asp second stage lit and off we go.  Looking good…for a few seconds.  Then the smoke trail changed a bit.  That didn’t look quite right.  But she is still going up.  Wait, the second stage parachute should be out.  Oh, there it is.  That definitely is not right.  There is nothing under the chute.  Plus it should be a lot higher.  We definitely had a problem.  Then we noticed a large section coming down with no chute just trailing some cords to the east.  No sign of the rest of the rocket.  The Nike booster came down just fine.  No problems there.  Now we need to find the as many parts as we can.  The radio trackers came out and then the nose cone was found, but still no sign of the rest of the rocket.

From studying the pictures, we definitely had an anomaly shortly after staging.  Our theory is that as the rocket went transonic or just supersonic we lost a fin.  That caused a deviation from the flight path that increased the angle of attack.  This over stressed the airframe and it broke up.

At least we got the booster back.  I’m sure at some point in the future we will try another club project, but for now we’ll take a break.

Still it was a great LDRS 38, mostly good weather and lots of great flights.