Build Thread - Wildman Piercer 98

[kswing]

One of the elves told me that I'm getting a Wildman Piercer 98 for Christmas, so, I'm going to do a build thread on it. I've also heard that it will have a 6-1 nose cone in place of the standard 4.5-1, so, it should stand about 72-73" tall. This will be my first fiberglass rocket, so, it will be a bit of a learning experience. I'm not too concerned about the fiberglass since I've built a few other HP rockets before (cardboard/blue tube/canvas phenolic) and I've also built other things out of fiberglass (RC airplanes, sea kayak). So far I'm planning to use T-88 epoxy for everything except the fillets where I'm planning to use RocketPoxy. I'm planning to do redundant (head end) dual-deploy, but, I haven't chosen the altimeters yet.

Here's a link to the kit on Wildman's site: https://wildmanrocketry.com/collections/wildman-4-inch-kits/products/piercer-98

If you follow this, I'll warn you that this will likely be a slow build thread as I don't even have the kit yet and I also have family/work/other commitments that often occupy my time. I'll provide more details and pictures once I have them. I'm still trying to think of a good name and color scheme, but, here's a picture of how it might look once it's done:

 

[kswing]

Merry Christmas to those who celebrate it, otherwise, Happy Holidays!

Since it is Christmas I was finally able to open and check out this kit. It looks very well made and I'm looking forward to building it. Normally I paint rockets, but, with this I'm considering just filling it with clear epoxy since that would highlight the natural colors of the fiberglass parts.

I'm going to stick with standard HED dual-deploy with the main in the nose. For the avionics bay, I'm probably going to use U bolts for the attachment points on the end-caps and 1/4" threaded rod for the sled rails. I'm working on a system where I can share altimeters between rockets by keeping the rail spacing common. I'm also designing the altimeter sleds so that they can nest (back to back) if needed for redundancy. Using this system, I'll probably have it flying with an Eggtimer Quantum along with an Eggtimer Quark for redundancy.

For the recovery harness, I'm planning to use 3/8" tubular kevlar attached to the MMT and then 5/8" tubular nylon (TN) for the rest so that it has a bit of give. I'll use a ball bearing swivel between the kevlar and the TN so the fin can can spin without causing trouble. I'm not sure on the drogue chute yet, but, for the main I have a 50" chute from another kit that I think may work. I'm planning to do some calculations on it once I know the completed weight and adjust as needed.

I still need to give it all a bath, but, here's what the kit looked like once it was unpacked...

 

[kswing]

Here is the obligatory dry fit picture. It comes out to about 73.5" inches tall. I've tried out some spray clear gloss on one piece and it looks nice, so, I think I'm going to just going to leave the nose cone and body tube natural colors with clear-coat. I'm not sure the natural color of the fins fits well, so, I'll probably paint them black or maybe dark green.

 

[Theory]

NICE!!!

looking forward to seeing her fly

 

[kswing]

NICE!!!

looking forward to seeing her fly

Thanks! I'm hoping to have it ready for Battlepark by February.

I'm not making major progress today because I'm currently waiting on a swivel for the booster harness and some 1/4" kevlar for the main harness. I decided to switch to 1/4" tubular kevlar for the main since it will take less space in the nose. I did round the edges on the fins and spray a few coats of clear gloss on the nose and below is how it looks so far. I sanded it with 600 grit, wiped it with acetone and then sprayed it a few hours later. It looks more glossy in person than in the picture, but, I'll probably still cover it with one or two more coats to get a nice glossy look.

 

[Theory]

Cool deal.

Those WM nose cones really look good with only some clear.

Cool this kit has the 6-1. Believe that is the best looking nose cone currently on the market!

 

[kswing]

Those WM nose cones really look good with only some clear.

Cool this kit has the 6-1. Believe that is the best looking nose cone currently on the market!

I agree the 6-1 is the best looking N.C. I've seen. The kit came with a 4.5-1, but, I wanted a bit more space in the nose, so, I chose to upgrade and pay the difference.

 

[kswing]

The swivel I'd been waiting for arrived yesterday, so, I finally got to glue some parts together. I roughed up all of the parts with sandpaper and then wiped off the dust with acetone. I had already used a file to notch the top CR for the kevlar harness, so, I did a dry fit of the centering rings with a fin and then tacked the top CR to the MMT with some thick CA. Next I epoxied the top CR to the MMT and then epoxied one side of the recovery harness to the MMT. Once that has set I'll glue the other side of the harness to the MMT. I'm mostly following the instructions that can be found on WM's web site. Here are some pictures:

 

[Theory]

I agree the 6-1 is the best looking N.C. I've seen. The kit came with a 4.5-1, but, I wanted a bit more space in the nose, so, I chose to upgrade and pay the difference.

Good call! Did the same thing with my WM Drago 4

 

[kswing]

Today I glued the switch band onto the tube coupler and I also started to cut out my fin alignment guide. For the guide, I'm using foam poster board that I've marked with a compass and protractor. I cut out the center circle and then a slot for each fin as needed. I'll slide it over the body tube as I glue the fins to ensure they are aligned properly. Here are some pictures:

 

[kswing]

Today I was finally able to make a bit more progress on this. Progress had been stalled for a few days because the power to my house was out due to a big snowstorm.

A few days ago I glued the MMT into the body tube. Initially I only glue the upper CR (on the MMT) in to the body tube and just temporarily install the lower CR to be sure the MMT is aligned properly.

After the MMT had cured for a few days and the power came back, I started gluing fins. I sand and dry fit everything first to be sure it will line up properly. Next, I coat the root of the fin tab with epoxy, insert it so it touches the MMT, then remove and repeat it so that it has good initial amount of epoxy on the fin tab/MMT joint. Internal filets will be handled once all the fins are glued.

For this rocket, since it has long fins, I also drew a line extending the fin slot up the body tube to be sure the forward part of the fin was straight. Once the fin is inserted, I put on my alignment gauge/jig to be sure it is straight and then leave it for a day for the epoxy to set. Below are some pictures.

In the jig without the bottom CR. It may look a bit crooked, but, it isn't. The plastic wrap in the MMT is there in case epoxy gets spilled. The dark patches on the body tube are tape on the outside identifying specific fin slots and the location of the lower rail button.


With the bottom CR temporarily installed to be sure everything is aligned properly:

 

[kswing]

Today I also configured one of the end-caps on my avionics bay. I'm setting it up for redundant dual-deploy even though I may sometimes fly with just one altimeter. I'm using CPVC end-caps as my charge wells and terminal blocks to connect my e-matches. The wires from the terminal blocks connect to the altimeter(s) via JST connectors, so, I can easily disconnect and re-use the altimeter in another rocket. I will tag the wires with colored tape to ensure that I don't mix up my main and drogue connections. I use a bit of epoxy to plug the holes around the wires to prevent any hot gas from getting near the altimeter. The open holes are where the 1/4" all-thread rods will go and they will be terminated by fender washers and nuts on the fixed end and fender washers and wing-nuts on the removable end.

Here's a picture:

 

[deandome]

looks great; did you just epoxy the charge wells and terminal blocks to the ebay lid? does that hold up OK?
I've previously attached blocks with tiny screws, but it's a hassle...gluing is probably fine, whats the worst thing that happens; it comes loose after the charge, no problem.

Epoxy seems like overkill for sealing the wire-hole, IMO. wires need to be replaced now n then, why make that such a pita? I use hot glue or silicone sealant

 

[Hobie1dog]

Thanks for the clear pictures

 

[kswing]

looks great; did you just epoxy the charge wells and terminal blocks to the ebay lid? does that hold up OK?
I've previously attached blocks with tiny screws, but it's a hassle...gluing is probably fine, whats the worst thing that happens; it comes loose after the charge, no problem.

I do just use epoxy to glue the terminal blocks and charge wells and so far it has worked fine in my other rockets. I usually just use 15 or 30 minute epoxy and I rough up both the plastic and the end cap to help the glue get a better hold.

Epoxy seems like overkill for sealing the wire-hole, IMO. wires need to be replaced now n then, why make that such a pita? I use hot glue or silicone sealant

Thanks for the suggestion. Epoxy probably is overkill for sealing the wire holes. For the other end cap I'll have to try some silicone sealant.

 

[Tractionengines]

The swivel I'd been waiting for arrived yesterday, so, I finally got to glue some parts together. I roughed up all of the parts with sandpaper and then wiped off the dust with acetone. I had already used a file to notch the top CR for the kevlar harness, so, I did a dry fit of the centering rings with a fin and then tacked the top CR to the MMT with some thick CA. Next I epoxied the top CR to the MMT and then epoxied one side of the recovery harness to the MMT. Once that has set I'll glue the other side of the harness to the MMT. I'm mostly following the instructions that can be found on WM's web site. Here are some pictures:
View attachment 497680View attachment 497681

Just looking at this thread and have a quick question; What are the ratings of that swivel? Where did you get it from? It looks undersized based on the rest of the recovery setup. A lot of various ratings are used for swivels depending on supply/use. (Ultimate strength where it fails, working load based on some safety factor, some seem pulled out of thin air, etc) Since that location can see a lot of shock load, extra capacity is needed.
I am not saying is IS too small, or that you didn't evaluate the loads, just going by looks..

 

[kswing]

Just looking at this thread and have a quick question; What are the ratings of that swivel? Where did you get it from? It looks undersized based on the rest of the recovery setup. A lot of various ratings are used for swivels depending on supply/use. (Ultimate strength where it fails, working load based on some safety factor, some seem pulled out of thin air, etc) Since that location can see a lot of shock load, extra capacity is needed.
I am not saying is IS too small, or that you didn't evaluate the loads, just going by looks..

Although it looks small, the swivel is rated to 530 pounds, so, hopefully that will be enough. I ordered it from Amazon and it looks solid with welded rings. I have a similar swivel in another 4" rocket and so far it has worked well. In general I've been designing for a rocket that is about 9 pounds, maybe even less, with a 50G safety load factor.

Even though I think it will work, I do like to be cautious, so, I may try to do a strength test on a similar swivel using some weights or a come along.

 

[kswing]

Over the weekend I glued on the rest of the fins and also did 2 out of the 4 internal fillets. I'm using RocketPoxy for the fillets and it works well but can be messy. I'll try to get some pictures when I do my next set of internal fillets.

Today I worked a bit on my electronics. I'm using two avionics sleds, one with an Eggtimer Quantum and the other with an Eggtimer Quark. Each sled has its own altimeter, battery, and switch. The sleds ride back to back on the allthread rods. Whenever possible, in each rocket, I use a common spacing of the allthread rods so that I can switch avionics between them by just swapping one of the avionics sleds. Also, I apologize if some of the following picture didn't come out really clear, my phone doesn't always pick the proper focus point.

Here's a side view of how the sleds fit together. The 1/4" allthread rods are running horizontally through the picture and the sleds are mounted to them using 1/4" launch lugs. 1/2 of the launch lugs go with the Quark sled and 1/2 with the Quantum sled.



Here is a view of the Quantum sled. The screw switch is on the left and since the Quantum is armed via WiFi this switch will be accessed (at the car) via a hole in the lower avionics coupler shoulder. The bubble wrap holds a 2S 300 mah Lipo battery. I use plastic stand-offs and screws to mount the altimeter and I thread them into the plywood sled by drilling a hole very slightly smaller than needed and then slowly screwing them in. I typically only use two screws for the altimeter and so far it has worked well. I still need to add the wires with JST connectors for the main and drogue charges and overall I still need to cleanup/manage my wires better:




Here's a view of the Quark sled. The screw switch for this (in the middle) will line up with one the vent holes in the switch band.

 

[kswing]

Today I did another set of internal fillets and took some pictures. The fillets are probably overkill for this rocket, but, they don't add that much weight and they will help make it stronger.

I use a three popsicle sticks taped together to get the epoxy toward the forward centering ring, but, they can be hard to keep steady so it can get a bit messy. I wipe off any epoxy that might interfere with the bottom CR, but, I don't worry too much about the rest. Also, I put some epoxy in and put the tube at an angle with the top down for about 10 minutes to let it flow toward the front. After that, I tape the bottom to ensure the epoxy stays in place and I level the tube. I'm using RocketPoxy and for the internal fillets I try to use it quickly so it flows a bit.

Here are some pictures:

 

[kswing]

Yesterday I finished the internal fillets, so, today I glued on the lower centering ring and then mounted the motor retainer. I used RocketPoxy to glue on the CR and to create the fillet. For the fillet, I let it sit for 15-20 minutes before using it so it has a chance to thicken up a bit. I'm using a flange-mounted Aero Pack retainer. I ordered a new one for this rocket, but, it hasn't arrived yet so I "borrowed" one from one of my other rockets. Also, I use stainless sheet metal screws in place of the socket head screws that came with it as they are easier to work with. Here's the lower CR with the retainer:



I also stitched the end loops in the 5/8" tubular nylon that I'm using for the drogue harness. I stitch them using Kevlar thread with a sewing awl by following directions that can be found in a video on John Coker's (@JohnCoker) rocketry site. Here's one of the loops:



Today I also assembled the other end plate for my avionics bay. I'd include a picture, but, it looks almost identical to the one I posted earlier. The only minor difference this time, based on a suggestion from @deandome , I used hot glue to seal the wire holes and so far it looks to have worked well.

 

[Theory]

Nice work

agree that the sheet metal screws for the flanged retainer are easier to work

also, do not believe that internal fillets are overkill. Not sure the “upper” fillets are needed, but the ones you used against the motor mount definitely are.

 

[Tim51]

I'm using a flange-mounted Aero Pack retainer. Also, I use stainless sheet metal screws in place of the socket head screws that came with it as they are easier to work with.

Good call, as @Theory said. I have 3 AP flange retainers, and I've swapped all the screws for M3 slot pan heads. That's partly due to me owning more metric fixings (I use M3 inserts), so that replacing a lost screw is easier, but I also find they're easier to tighten when changing between rockets.

Nice build, by the way.

 

[kswing]

Yesterday I started work on the external fillets. I should have been out launching in the cold at BattlePark, but, since I had mild cold-like symptoms I chose to stay home.

I'm using RocketPoxy for the fillets and I'm using red dye with it so they blend with the body tube. I tape off the area for the fillets first and then I apply the epoxy just after I mix it so it still flows a bit. I use a popsicle stick to shape the fillet and then I use a squared off tongue depressor to remove any excess. I also dip a gloved finger in rubbing alcohol and use it to smooth things out if needed.

The first set came out just a bit messy, but, the rest are looking better. Here are some pictures:

Here's the tube taped off for one of the sets:


Here's the first set, it's a bit messy, but, it should sand out ok:

Here's the latest somewhat cleaner set:

 

[crossfire]

Yesterday I started work on the external fillets. I should have been out launching in the cold at BattlePark, but, since I had mild cold-like symptoms I chose to stay home.

I'm using RocketPoxy for the fillets and I'm using red dye with it so they blend with the body tube. I tape off the area for the fillets first and then I apply the epoxy just after I mix it so it still flows a bit. I use a popsicle stick to shape the fillet and then I use a squared off tongue depressor to remove any excess. I also dip a gloved finger in rubbing alcohol and use it to smooth things out if needed.

The first set came out just a bit messy, but, the rest are looking better. Here are some pictures:

Here's the tube taped off for one of the sets:
View attachment 500166

Here's the first set, it's a bit messy, but, it should sand out ok:View attachment 500168

Here's the latest somewhat cleaner set:
View attachment 500169

I normally let my rocket proxy set for 10 minutes after mixing it. It vents of air bubbles and it early helps with no air bubbles in fillets

 

[kswing]

I normally let my rocket proxy set for 10 minutes after mixing it. It vents of air bubbles and it early helps with no air bubbles in fillets

Thanks for the advice; I'll keep that in mind for the next set since I've got one more to do. The way I've been doing them I probably end up waiting 5-10 minutes just mixing in the color.

Also, since rockets need a name, I've decided to name this rocket "Blitzen" which is German for "flash". I'm planning to just clear-coat the nose and body tube and I'll probably paint the fins a dark green.

 

[crossfire]

Thanks for the advice; I'll keep that in mind for the next set since I've got one more to do. The way I've been doing them I probably end up waiting 5-10 minutes just mixing in the color.

Also, since rockets need a name, I've decided to name this rocket "Blitzen" which is German for "flash". I'm planning to just clear-coat the nose and body tube and I'll probably paint the fins a dark green.

Sounds like it will be a great looking rocket.

 

[kswing]

In the past few days I finished the fin fillets and drilled for the rail buttons. I drilled 1/8" holes for the rail button screws and then tapped them with the rail button screws. I also drilled 5/64" holes for the shear pins. I'm using 3 2-56 shear pins for the nose and just one for the booster. Since everything is done except for painting, today I tried a few ejection charge tests. I'm using the Eggtimer Quantum for testing since I can trigger it via WiFi.

Here's the booster charge using 1.7 grams of 4F:
View attachment VID_20220122_153749051.mp4

















For the nose test, first I used only used .8 G and it didn't separate. So, for the second test (shown below) I used 1.2 G and it mostly worked except the parachute stuck in the nose cone. Tomorrow I'm going to re-pack the chute a bit smaller and use a slightly smaller nomex blanket and maybe add one or two 1/10s more of 4F and try again.
View attachment VID_20220122_144603542.mp4

 

[Theory]

FWIW, after having my chute’ hang in the nose, I’ve gone to a full 2g there and 2.5 - 2.75 on the booster.

that’s in my WM Drago 4 with the same nose cone. Iis fg so you won’t break it and the extra insurance is good.

 

[Theory]

Think this way, when you’re watchin her fall from 4K with no deployment or the main fires at 500 and the chute hangs, it’s silly to think that you saved .5g

 

[jd2cylman]

Is this HED? If so, put your charges in the nose tip and fasten the chute to the AV bay lid. Perfect deployment every time for me this way. If you don’t like the chute directly on the bay lid, at least keep it under 1/4 of the shock cord length close to the bay lid. YMMV.