5" Wildman Gizmo Build Thread

[EeebeeE]

After shredding a paper/plywood rocket at LDRS this year, and having ongoing struggles trying to keep from damaging a QT rocket, but still trying to push the envelope, I decided it was time that I used much stronger material to build my rockets. two reasons. First, I hate replacing kits. Second, once I build a rocket, I don't want to waste time fixing it. I'd rather spend that time building another rocket.

This is my first foray into fiberglass rocketry so I chose a Wildman Gizmo. Seemed to be a straightforward build...until I simmed some flights with it and realized that it can fly well more than a mile up. That means I will need to make it dual deploy. I am thinking I will put a 54mm tube in the nose cone and blow the main chute out of it.

First, the obligatory kit shot. The kit is pretty bare-bones. I bought a couple U bolts so that I can glue the fincan together. The rest of the materials will be ordered this week.



This is taken after everything is sanded. Had to work at the centering rings because the motor tube holes were a little narrow, but it only took about 10 minutes per ring or so to expand them out to where they needed to be. Used 60-grit sandpaper for the fin roots, and 250 grit for the rest. I rough sanded the seams of the nose cone with 60-grit, then used 250 all over the nose cone to even all that out as well. The motor tube is sanded with 60-grit, and the airframe is done with 250. I will rough up the edges of the fin slots with my dremmel later on.

I'm a little disappointed that the trailing edges of the fins weren't beveled, but I am going to leave them as is. I think the slight amount of increased drag will actually help the stability, given that this is such a short rocket.

Once all was sanded I test-fit everything to see if it would all go together well. The base of the nose cone seems a little out of round, but I think I can address that with the bulkhead.



This is the design in Open Rocket. Note the motor that fits in here and the potential altitude. Since I am using another 54mm motor tube to hold the main, I am somewhat limited in chute size. The sims suggest I needed a chute that is 45" in diameter. Concerned that it would not fit, I am opting instead to go with 2 27" diameter chutes. In addition to being easier to pack, they should also help the landing stability, and it should look kind of cool. The tracker and the Perfect Flite Stratologger will go forward into the nose.



To vent the altimeter, I will drill 3 x 1/8" holes about 1/4" below the top of the nosecone shoulder and then drill 3 holes in the bulkhead. I will then create tunnels connecting the holes so that the air is vented behind the nose cone. In the section of the 54mm tube that holds the altimeter, I will drill 3 x 1/4" holes to make sure that I get enough venting there as well. I have to figure out how I am going to install the switch. Otherwise I think what I have done will work.

Suggestions are welcome.

 

[jd2cylman]

If you fly it Wildman style, you don't need dual deploy. At the club launch earlier this year, Tim launched his on a huge green motor. He didn't need nomex, because the chute was BELOW the ejection charge :eyepop:

He used a 30" chute and a tracker. We saw it go up, go out of sight, then never saw it again til the tracker led us to it.

Adrian

 

[Disaster_Guy]

I look forward to following this build.

 

[bill2654]

The Gizmo is my favorite rocket in my fleet. I have two regulars and did my L2 at Airfest with my GizmoXL. I want to buy another nose cone and set it up for DD for my regular ones. I'll be watching this thread.

 

[Disaster_Guy]

I want to buy another nose cone and set it up for DD for my regular ones. I'll be watching this thread.

That's what I was thinking as well...

 

[DANLK66]

I did my level 2 with a Gizmo on a J250 skid. It went about 3500ft and I was able to see it land not far from the field. You can't go wrong with a Gizmo. Put a tracker in it and any motor that will fit

 

[EeebeeE]

Probably one of the more bland steps in the process is putting in the ballast, but what the heck. Most threads I have seen on a Gizmo have had about a pound. I settled on 12 ounces, figuring that the DD setup will weigh 4 ounces.

Thanks to the folks at Biekirch Ammunition Supply, I was able to secure lead #8 buckshot instead of zinc. Go figure. It is next to impossible in New York state to get black powder, but you can get lead buckshot. The lead is heavier than the zinc, so it takes up less space in the nose, which is precious, and also moves the CG forward.

I used auto body fiberglass epoxy since it takes longer to cure, has more fluidity, and since the cure time is longer the temperature stays down. I mixed about 1.5 oz. of epoxy and poured about half of it in the nose. Then I poured in about 8oz. of buckshot. Then I added a little more epoxy and the rest of the shot. I ended up with about a 3/16" covering of the shot with the epoxy. I had enough epoxy left so I could keep it in a small container and better gauge the temperature. If the reaction gets too hot, you can melt your nose cone...which would suck.

I then set the nose cone in the airframe tube to keep it level. About a half-hour later I noticed that the temperature was getting pretty hot, so I filled a cup with icewater and rested the nose cone in it. That worked very well, and I had no deformation.

The other reason I wanted to mention the ballast is for safety. When working with lead, It is best to use buckshot as opposed to melting it because lead gives off fumes when melted. Also, if you touch lead, wash your hands with cold water afterward. When lead oxidizes, the lead oxide can rub off and get on your skin. If rinse with cold water and no soap, your pores stay closed and the lead oxide, which is water soluble, is easily removed. If you wash with hot water and/or with soap, your pores open and the lead oxide can get into your system (bad thing). Incidentally, this approach works effectively with poison ivy as well.

Nose cone in icewater.



Finished ballast

 

[EeebeeE]

I did my level 2 with a Gizmo on a J250 skid. It went about 3500ft and I was able to see it land not far from the field. You can't go wrong with a Gizmo. Put a tracker in it and any motor that will fit

I want to test fly this with a J250. I have run sims on a K454, a K2045, and some other 4-grain monsters. According to Open Rocket, a K454 skid will put this up to nearly 6,000 feet...and look freakin' awesome! That's why I want to go DD.

 

[Disaster_Guy]

Maybe I missed it somewhere but what is your expected built weight? Mine comes in right at 9lbs flight ready with a 3 grain motor.

 

[EeebeeE]

Dry, it should come in somewhere around 6 pounds. I weighed the airframe components and they all come in at 5 lbs. 4 oz. I bought an 11-pound scale that measures to the nearest 0.1 ounces. I have been disappointed with the weight estimates from Open Rocket. It tends to estimate way light. With a CTI K2045, It should come in around 8 pounds, give or take a couple ounces.

 

[tbonerocketeer]

Just drill your vent holes at the base of the cone, before the airframe joint. Works just fine.

 

[gregm]

Maybe I missed it somewhere but what is your expected built weight? Mine comes in right at 9lbs flight ready with a 3 grain motor.

Mine was 7 pounds when it flew at Airfest on a J1055. 10 second delay was absolutely perfect!

I hated this rocket with a passion until that flight. Now it is getting an upgrade. New long nose cone makes it look a lot better to me. Shouldn't hurt how it flies either. Will be adding an altimeter for dual deployment so it can fly on the biggest 54mm motors.

 

[EeebeeE]

Parts for the DD system were ordered today as well as my motor retainer. The DD concept is to load the electronics far forward in the nose cone. Separate the electronics/main chute tube with a bulkhead, attached to a removable coupler tube. The eyebolt would be 6" long and go through the E-bay to also serve as the sled holder. Another coupler tube inside the e-bay acts as a stop for the bulkhead of the removable parachute tube as well as a stop on the forward end for the forward bulkhead. The chute tube has to be removable so that a bp charge can be loaded. Toward the aft end of this structure is a cap to hold the main in the chute tube. It will be tethered to the main shock cord. The entire assembly has a 3" centering ring glued to the aft end so that it can be screwed to the nose cone bulkhead. from the forward end of the electronics to the drogue deployment BP cannister. Wires run through one of the ebay vent holes to the drogue BP cannister.

In this configuration I think I only need about .5 grams of BP to deploy the main and probably 2.5-3 grams for the drogue. With the chute/electronics tube being filled end to end with coupler tubes it should be strong enough to hold the weight of the rest of the rocket as it descends. A relatively small BP charge in it should also reduce stresses on it. I am using LOC parts for this.


The design is in the attached file.

 

[bill2654]

Evan, have you checked out GaryT's thread? https://www.rocketryforum.com/showt...quot-GIZMO-XL-FROM-PERFORMANCE-ROCKETRY/page2

 

[EeebeeE]

I had seen that one as well as others. You have a lot more room in the 8" Gizmo than you do the 5". In the 5" if the nose cone bulkhead is at the forward end of the shoulder and you want to use a CTI 4-grain motor, there is 3/4" clearance from the top of the motor to the bulkhead.

To make sure I have enough room for my transmitter antenna and to maintain structural integrity of the bulkhead, I felt I had to keep the AV Bay/Chute tube down to 54mm in size. Also A 4" hole in the bulkhead still leaves 1.75" on either side to put in an AV bay in the 8" Gizmo. I drilled a 2.26" hole in my bulkhead and I have little more than an inch left on the outside ring. Cutting out another hatch large enough to put in a sled and a battery would severely weaken that part of the bulkhead.

My approach therefore was to have the entire electronics and chute compartments be single removable unit that is bolted to the bulkhead (I will probably use threaded inserts and screws). It is a challenge and it means running and securing some wires that are permanently installed.

 

[bill2654]

Hope you post a lot of pics!op:

 

[EeebeeE]

As I wait for the recovery parts, there is still work to do. Part of what I want to do with this rocket is to have some learning for my L3. Part of that involves making sure my fins stay put while the rocket is flying. So I had sone 3" fiberglass strip laying around from a plywood kayak project from last year and decided that I would use it to make my internal fillets. I felt that by using this material, external fillets would not be necessary, which would be helpful in case I wanted this rocket to break Mach 1. Again using automotive fiberglass epoxy, I cut 8" strips of glass tape, got it wet, and with a piece of scrap pine from the boat project, pressed it against the fin root and then onto the motor tube and the inside of the airframe.

Gotta tell you, this is freakin' messy, and it is exacerbated by the fact that you have to work fast before the epoxy gets sticky. Fortunately, it was a cool night and I did it outside so that the chemical reaction time slowed down. Also, no epoxy dripped down the motor tube, and the epoxy that dripped on the outside of the airframe was easily wiled off. I will sand before painting anyway.

It really only added about 3 ounces to the rocket weight, so I am pretty satisfied how it turned out.

I am pretty sure these fins are going to stay put.



Oh yeah. Since I mentioned the kayak, you might be wondering what it looked like.

 

[eggplant]

First off, awesome Kayak! That looks beautiful. About the rocket though, I think your fiberglassing method was inefficient. I am not quite up to the level that you are at, but I have done some fiberglassing and to be it makes sense to paint the surface with resin first, they lay the fiberglass on top of that, and then paint more resin on it. The mess would have been much smaller, but it looks like it turned out well anyway. I can't wait to see what engine you put in this!

 

[EeebeeE]

I agree with the painting with resin, and tried it, but because it was so confined, the glasscloth started coming apart and I could not get it as confined into the corners. It was much easier to bathe the cloth then slide it into place. Prior to doing this I had sanded the entire area with 60-grit sandpaper, so it had a real good grip. On a rocket where I can get my hand into that space, I will do it the other way.

I checked it this morning and everything seems to have bonded very well although I may have to inject a couple gaps with quick-setting epoxy.

 

[blackjack2564]

Evan,
First off that's a gorgeous job on the boat. I saw you mentioned pine, but the skin doesn't look like pine to me. Pine for structure or ribs?
If it is pine[ the skin]what type, inquiring minds would like to know. I always appreciate beautiful wood water craft. The Old mahogany Chris Craft's speed boats from the 30's-50's were works of art.

Any how, I used to work/ build fiberglass boats back in the day myself. When I began building rockets, I too carried over those techniques to this hobby. As time went on I knew there had to be an easier way that was structurally just as strong. I used to glass strip the fins on MM tube....slot the airframe to the end and insert the pre-built fin/motor tube assembly. It WAS messy and cutting the slots out to the end screwed with the airframe integrity.

External fillets are not needed on projects like the Gizmo... there are none on mine.[it's not painted though]

On L-3 sizes they do become a structural component AND are really needed to get a good paint job.

Then I came upon the injected internal fillet method. I have done several instruction manuals and builds outlining this and one of the best can be found here:

https://www.wildmanrocketry.com/ProductDetail.aspx?product=2902

It can be done on any type material and scaled up or down to fit whatever size airframe you are working on. I've done it on 2in. airframes up to the giant 12in. "Mega Darkstar"

Download those instructions and take a look see. It might make your journey to L-3 a more pleasurable one.

Good luck on your L-3 & Semper Fly!

CJ

 

[EeebeeE]

The boat is made of 3/16" Okume plywood. The pine is for stringers and gunwhales. It has two oak beams, and an oak transom. 16' long and it weighs 52 pounds. That is very light for a boat that size. The construction method is called "stitch and tape" aka "Stitch and glue." You cut the plywood according to the plans, drill holes in the edges that need to be joined, then "sew" the plywood together with copper wire. Once the stitching is done, you then epoxy the seams and cover with strips of fiberglass. Some plans also call for glassing the entire hull and deck. This one didn't. It is a Selway-Fisher design called a "Dart 16." The design came from the UK, and I had to adjust it to fit the more common American lumber specifications for the gunwhales, stringers, keel, and the "hog" (internal keel).

You can see more about the design here https://www.selway-fisher.com/Kayak.htm

She handles beautifully, and you can see a video of how she went together on YouTube.

I haven't looked into internal fillets, but I probably should. I don't know whether I will go for my L3 next year, the year following, or make it a 2-year project. I am thinking about doing a 3x upsize of the Estes Der V-3. That was my first D engine rocket back about 25 years ago, and I just lost the rocket in a tree last year. What better way to resurrect it than to make it a Der V-3-cubed.

[YOUTUBE]wzguLryi5E8[/YOUTUBE]

 

[EeebeeE]

I was a little disappointed that the DD parts did not arrive yesterday, but such is life. So I spent the weekend sanding, and installed the lower centering ring. I got the primer on it this afternoon. I have gotten into the habit of drilling the holes for the buttons and then painting the rocket without the buttons installed. Then when it is time, I drill out the paint holes and glue the buttons in place. The hole above the fin is for the video camera. I buy MD 80 cameras from China for a buck a piece ($10 shipping) and they take adequate videos. Figuring that this rocket will hit 7,000 feet, an $11 camera is worth the price and the video extends the value of the flight, considering that I am paying $110+ for the motor.

 

[EeebeeE]

Now that the parts for the DD have come in, I have started laying everything out, cutting tube, laying out my electronics and gluing bulkheads.



The tip of the nose cone would be pointing to the left in this picture. The 54mm tube will be entirely removable and will hold both the electronics and the main chute. Starting from the left, there will be an inner sleeve that will be glued inside the tube a half-inch deep from the forward end so that the forward bulkhead section will be flush with the forward end of the 54mm tube. With the inner sleeve glued in place, the 2 bulkheads will be tightened in place by the long eyebolt, and that completes the electronics bay which is fixed in place inside the 54mm tube.

A small powder cup will be attached to the aft e-bay bulkhead. which will blow out the main chute. It should only take about a half gram of powder to eject the 36" chute. A cap on the aft end of the 54mm tube will hold the main in place. the aft end of the 54mm tube has a 3" centering ring glued to it. Holes will be drilled into the centering ring and through the nosecone bulkhead. #6 nuts are glued to the forward side of the nose cone bulkhead. Screws go through the 3" centering ring and the nosecone bulkhead into the nuts.

Wiring from the forward end of the e-bay will go through a notched area of a forward centering ring (not pictured) that helps to hold the forward end of the 54mm tube in place. The wire is a "4-flat" setup that will go through the nose cone bulkhead and connect to the charge and switch. The switch will be a springloaded lever switch that will be held in the "off" position by a removable pin that will be pulled out from the outside of the rocket. There will be a powder cup on the aft side of the nose cone bulkhead that will hold about 2.5 grams of powder which will separate the nose cone from the aft end of the rocket.

The antenna for the transmitter will go through a hole in the ebay needed for the altimeter and will slide into a couple launch lugs on the side of the 54mm tube. It is pretty cool that I can get my beeline and stratologger side by side into a coupler tube. It is also pretty amazing how much room is freed up by moving the switch outside the ebay.

 

[Disaster_Guy]

I am really digging this build. Please keep on posting with plenty of pictures. I am thinking that once my wallet is freed up a bit it may be time to order a second nose for mine.

 

[EeebeeE]

Thanks. I'm having fun with it myself. We have a club launch in 8 days and I want to have it done by then so pics will be coming fast and furious over the next couple days. I have a CTI J760 White Thunder to stick up its motor hole for its maiden flight. Should go up 4,750'-5,000' ... and make a lot of noise doing it.

 

[Disaster_Guy]

That should be a good flight. I tend to fly mine on the J360 Skidmark, J1055 and J1520 VMAX. Do you have a feel with your DD design what the largest case you will be able to fit will be?

 

[EeebeeE]

I am making sure it will hold a 4-grain CTI case. My goal is to fly it with a K454 and a K2045.

 

[Aksrockets]

You should also consider the K740C*! Nothing on earth quite like a good C-star.

Loving the build BTW...

Alex

 

[EeebeeE]

It sims very well. Busts mach and goes HIGH. Now you can understand why I glassed inside the fincan instead of using fillets. Those fins aren't going anywhere other than where the rocket goes.

 

[UPscaler]

You should also consider the K740C*! Nothing on earth quite like a good C-star.
View attachment 98811
Loving the build BTW...

Alex

+1. The K740 is an awesome motor!



Braden