LOC ISQY Tomahawk Build Thread

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Zbench

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My daughter picked out this rocket because she liked the looks of it and also it flies on 29mm motors which are relatively inexpensive and don't require hazmat to ship. We started on it this past weekend and have benefitted from other's threads, so thought I would post our progress here.

Having built a few rockets with fins assemblies outside of the booster tube, I really wanted to do that for this rocket. Problem is that isn't possible with the supplied rings. After thinking about it for a bit, I realized I could create something with my CNC that would serve that purpose. I devised a thicker ring that has slots cut into it to hold the fins at perfect 90 degree angles to the motor mount and allow for an outside the tube construction approach. Here are the rings freshly cut from the sheet stock:
rings.jpg

While the stock kit only comes with two rings and a short tube, I opted to make a longer motor mount and include a third forward ring. The thicker rings will also come in handy to screw in the rail buttons later. The stock is baltic birch and is nominally 3/8" thick.

Before we could assemble the mount, I did a quick bevel on the leading and trailing edges using an 11 degree carbide chamfer bit and the router table:

bevel1.jpg

The result was nicely chamfered fins that will make a nice airfoil:

bevel2.jpg

Next was the glue up of the entire assembly. We used Rocket Poxy and you can see the finished result here. It made for a quick and easy assembly. To insure one ring was planar with the other, I scribed a line on the motor mount tube and made sure that the first fin root was exactly parallel to the scribed line. I also allowed enough of the motor mount to stick out to attach a motor retainer which will be glued on after finishing. Since there is a space between the fins and the rings that will be occupied by the booster tube, I had to be careful to clean out any epoxy that collected there. Also opted for a 8/32" screw eye frozen in place with epoxy:

fins.jpg

The bane of my existence for any of these projects is filling the spirals. I decided to try one of LOC's kits for fiberglassing the tubes and I have to say it worked great, even for the first time. I used CE 2000 epoxy that was made by by an outfit called resin research. It has an open time of about 30 minutes before it starts to harden. I made it in two batches, doing first the booster section and then the payload section. Big take aways are make more epoxy than you think you will need. I feel like it went on too thin on the booster which left some rough spots that I will fill in. I used a liberal amount on the payload and it came out as smooth as glass. The only thing that needs addressed on the payload section is the .002" high ridge where the edge of the one piece of mylar started. Make sure you have everything laid out. I weighed the 2:1 mixture by pouring it into a paper cup on a postage scale. I also used a cheap $1 Harbor freight chip brush which I was surprised shed very few bristles. Like maybe only two that I had to pick off the fiberglass. Start with lots of space and a taped down piece of freezer paper (coated side up) and all the stuff you will need:
fiberglass.jpg

I intended to document this more fully, but wearing gloves and working with sticky epoxy proved a challenge. So I didn't catch any more shots than this and the finished product. Some thoughts:
1) Pour the epoxy right on the fiberglass in as many streams as you can. the more the better as it's not like paint and the more uniform you can make it the better
2) Use the brush to work it all around on the fiberglass until it all becomes a uniform color.
3) It seems like the perfect amount of epoxy on the fiberglass is when you can't see the weave of the fiberglass anymore. if you can, it might leave a rough finish on the tube.
4) Don't expect the fiberglass to have a perfect seam--it will overlap and you will never be able to see where that is in the finished product. Just make sure that the seam of the fiberglass is not lined up with the seam in the mylar.
5) Roll the entire works on the tube and once you are like 3/4 of the way wrapped, carefully peel back the butcher paper and finish rolling the tube
6) With your hands, smooth out the fiberglass ensuring there are no puckers or gathers...this is mostly an issue on the end where the seam is, so take note
7) Once wrapped, pick the whole thing up and put it on the mylar and roll it up and tape in the middle. I used an old credit card to get the air bubbles out. One thing that i didn't fully realize until after it was dry is there are two kinds of bubbles. One type is large bubbles between the epoxy and surface of the mylar. These are easily worked out with the credit card. The other type are tiny bubbles in the epoxy itself that are not on the surface of the mylar. You will never get all of those out, but once the epoxy is dry, it won't matter as they are not on the surface and are very tiny. Perhaps these tiny bubbles are unique to my flavor of epoxy.
8) Leave the brush in the epoxy as a guide for when to cut the wrapped ends flush with a knife. it should be a little flexible and not hard. It is much easier to cut when it is not fully cured than it is after it hardens. I trimmed the ends flush and cut out the fin slots. I think I did that cutting about 4 hours after mixing. YMMV with your formulation of epoxy.

A shot of the finished product which is as smooth as a pvc pipe (at least the payload section):

wrapped.jpg
Not a hint of a spiral and it will really be a snap to paint. I think it was much less work than filling spirals and you have the added bonus of extra strength. Pretty excited about learning this new skill.

More to follow. Next step is to slit the booster and epoxy in the fin assembly.
 
My daughter picked out this rocket because she liked the looks of it and also it flies on 29mm motors which are relatively inexpensive and don't require hazmat to ship. We started on it this past weekend and have benefitted from other's threads, so thought I would post our progress here.

Having built a few rockets with fins assemblies outside of the booster tube, I really wanted to do that for this rocket. Problem is that isn't possible with the supplied rings. After thinking about it for a bit, I realized I could create something with my CNC that would serve that purpose. I devised a thicker ring that has slots cut into it to hold the fins at perfect 90 degree angles to the motor mount and allow for an outside the tube construction approach. Here are the rings freshly cut from the sheet stock:
View attachment 504728

While the stock kit only comes with two rings and a short tube, I opted to make a longer motor mount and include a third forward ring. The thicker rings will also come in handy to screw in the rail buttons later. The stock is baltic birch and is nominally 3/8" thick.

Before we could assemble the mount, I did a quick bevel on the leading and trailing edges using an 11 degree carbide chamfer bit and the router table:

View attachment 504729

The result was nicely chamfered fins that will make a nice airfoil:

View attachment 504730

Next was the glue up of the entire assembly. We used Rocket Poxy and you can see the finished result here. It made for a quick and easy assembly. To insure one ring was planar with the other, I scribed a line on the motor mount tube and made sure that the first fin root was exactly parallel to the scribed line. I also allowed enough of the motor mount to stick out to attach a motor retainer which will be glued on after finishing. Since there is a space between the fins and the rings that will be occupied by the booster tube, I had to be careful to clean out any epoxy that collected there. Also opted for a 8/32" screw eye frozen in place with epoxy:

View attachment 504731

The bane of my existence for any of these projects is filling the spirals. I decided to try one of LOC's kits for fiberglassing the tubes and I have to say it worked great, even for the first time. I used CE 2000 epoxy that was made by by an outfit called resin research. It has an open time of about 30 minutes before it starts to harden. I made it in two batches, doing first the booster section and then the payload section. Big take aways are make more epoxy than you think you will need. I feel like it went on too thin on the booster which left some rough spots that I will fill in. I used a liberal amount on the payload and it came out as smooth as glass. The only thing that needs addressed on the payload section is the .002" high ridge where the edge of the one piece of mylar started. Make sure you have everything laid out. I weighed the 2:1 mixture by pouring it into a paper cup on a postage scale. I also used a cheap $1 Harbor freight chip brush which I was surprised shed very few bristles. Like maybe only two that I had to pick off the fiberglass. Start with lots of space and a taped down piece of freezer paper (coated side up) and all the stuff you will need:
View attachment 504732

I intended to document this more fully, but wearing gloves and working with sticky epoxy proved a challenge. So I didn't catch any more shots than this and the finished product. Some thoughts:
1) Pour the epoxy right on the fiberglass in as many streams as you can. the more the better as it's not like paint and the more uniform you can make it the better
2) Use the brush to work it all around on the fiberglass until it all becomes a uniform color.
3) It seems like the perfect amount of epoxy on the fiberglass is when you can't see the weave of the fiberglass anymore. if you can, it might leave a rough finish on the tube.
4) Don't expect the fiberglass to have a perfect seam--it will overlap and you will never be able to see where that is in the finished product. Just make sure that the seam of the fiberglass is not lined up with the seam in the mylar.
5) Roll the entire works on the tube and once you are like 3/4 of the way wrapped, carefully peel back the butcher paper and finish rolling the tube
6) With your hands, smooth out the fiberglass ensuring there are no puckers or gathers...this is mostly an issue on the end where the seam is, so take note
7) Once wrapped, pick the whole thing up and put it on the mylar and roll it up and tape in the middle. I used an old credit card to get the air bubbles out. One thing that i didn't fully realize until after it was dry is there are two kinds of bubbles. One type is large bubbles between the epoxy and surface of the mylar. These are easily worked out with the credit card. The other type are tiny bubbles in the epoxy itself that are not on the surface of the mylar. You will never get all of those out, but once the epoxy is dry, it won't matter as they are not on the surface and are very tiny. Perhaps these tiny bubbles are unique to my flavor of epoxy.
8) Leave the brush in the epoxy as a guide for when to cut the wrapped ends flush with a knife. it should be a little flexible and not hard. It is much easier to cut when it is not fully cured than it is after it hardens. I trimmed the ends flush and cut out the fin slots. I think I did that cutting about 4 hours after mixing. YMMV with your formulation of epoxy.

A shot of the finished product which is as smooth as a pvc pipe (at least the payload section):

View attachment 504733
Not a hint of a spiral and it will really be a snap to paint. I think it was much less work than filling spirals and you have the added bonus of extra strength. Pretty excited about learning this new skill.

More to follow. Next step is to slit the booster and epoxy in the fin assembly.
Can I see more of your router setup please. I need to bevel some fiberglass fins.
 
I've been a pretty avid woodworker for 30+ years, so know a lot more about woodworking than rocketry. I built this router table a long time ago. The base is made of morticed and tenon lumber skids that were in good enough shape to plane down and glue together. The top is two 3/4" pieces of lumber core plywood glued and screwed together with formica laminate on both sides glued with contact cement.

The router hangs in a square hole fastened to a piece of 3/8" thick phenolic sheet. A mod that I recently did is buy that dust box which screws to the bottom of the table and completely encloses the router. There is a 4" dust collection hose hooked to the box and it draws a vacuum down through the hole in the phenolic sheet. A dust hood and smaller hose is on top and catches any stray dust from the top side. It's very effective.

The fence is just a piece of 6/4" maple with a hole cut out of one edge to allow clearance for the bit. To use it is a simple deal. You just eyeball how much you want to remove and clamp the fence on each end and test on a piece of scrap. The bit is a two flue carbide bit and it does have a bearing on top, but in practice, it never gets close to the plane of the fence. I usually set my fence so it is taking off a very light amount, run it through one side, then flip it and run it through the other. I then loosen one clamp and tap the fence over a little and repeat until I get it just right. I don't take my fins to a knife point, I leave a strong 1/16" uncut to give the edge some strength. Once set, just run all the pieces through and then run the other side.

IMPORTANT NOTE! Routers are inherently dangerous spinning at 30,000 rpm. If you get your fingers in there, you wont get a second chance. Always use a backer block to push the stock up against the fence like you see above. It keeps your fingers away from the action and is relatively safe if you keep your wits about you. You always want to feed from right to left so you are pushing against the rotation of the bit. To do it the other way is called climb cutting and it will grab your workpiece and zip it across the room. Another important thing to consider is if you have thick fins and a lot of waste to remove, you will need to take off the waste in stages, not in all one go. Carbide is not that sharp, just very hard. If you try to remove it all at once, you will get a lot of tear out that you will have to later fill. Just remember to work all the fins together with each movement of the fence until you get it where you want it. Of course, if you are beveling laminate, you won't be removing much stock as they are already pretty thin to start with.

Hope this helps.

router.jpg

This dust box is crazy effective. Not a hint of wood chips get into the workspace. You can see where the 4" flexible line connects at the back and then runs to a stationary dust collector. The dust hood on the fence connects to the box so it has a vacuum above and below.

router2.jpg

The router table is nothing fancy, but is very serviceable.

router3.jpg
 
We had some time tonight to glue the fine assembly into the booster. Before doing that I sanded out the booster. There are some very tiny pinholes which are voids in the fiberglass but they will easily fill with one coat of sanding sealer. Here I'm slitting the aft section of booster to allow the fin assembly to slide in:

slitting.jpg

Next. after applying rocket poxy inside the tube, we are sliding it in. A little tricky to get it started, but my daughter and I both took a side and got it started:

fitting.jpg

Finally seated:

seated.jpg

Here again is where a second set of hands comes in handy. One person pulls the flap of the body tube away from the aft centering ring while the other person spreads epoxy on the ring. The thick rings give a lot of bearing surface to glue to. Once complete, two nested clamps pull the carboard tube tight with the ring assembly:

clamped.jpg

Good progress for a school night, more to follow.
 
Work continues on the Tomahawk. While not really necessary considering the stoutness of the fin assembly, I do like the look of nicely formed fillets. Using Rocket Poxy, I tape off the fins with blue tape to match the radius of the 1/4" tool I use for this size rocket and glop on the epoxy with a popsickle stick and smooth out:

Fillet1.jpg

I pull the tape of course while it's still wet. I find about 15 min after smoothing it out is perfect. The finished result:

fillets.jpg

Spent some time figuring out how I want to recover this rocket. I decided on using an Apogee altimeter and the mount that Cris sells. I made a special bulkhead that is offset to allow for another 8/32 screw eye. It's a nice compact unit and can be removed easily to recharge the lipo. Rocket Poxy used on both sides to ensure it never comes out. I drilled the hole in the coupler to arm the altimeter and then slid the bulkhead in to line up with the hole in the coupler. I won't have an access hole in the tube, I'll vent the tube above the coupler to provide for equalization.

Coupler.jpg

Since this rocket has a large payload bay, I decided to just add a drilled and tapped 6/32 stainless cap screw to hold the nose cone on. I plan to push this one pretty high, so will hang an Eggfinder Mini inside the payload tube. While I was at it, I filled the seam with some bondo glazing putty and Tamiya spot putty. I think I like the Tamiya better. Either way, it's ready for finishing which will be red:

nosecone.jpg

Getting to the end of this one pretty quickly. This weekend I will seal the fins and get ready to finish the rocket. Going to use the traditional paint scheme of red nose cone, white body tube and one black fin. Thanks for looking.
 
Who is Chris Erving?

Purveyor of fine, do it yourself GPS Tracking Systems and Altimeters. I've used his stuff in virtually all the high power rockets I've launched. I personally enjoy putting them together, and then especially watching them work. There are no altimeters that come even close with respect to features when considering the very modest cost.
 
Work on the Tomahawk is nearing a close. I like to seal the plywood fins with a 2 pound cut of shellac. Since shellac is dissolved in alcohol, it dries really fast and makes an excellent base for the paint. I typically do two coats, with a light sand in between and after with 320 grit.

shellac.jpg

Another thing that I like is do is to ditch the stock rail buttons and make them out of acetal rod. Acetal is pretty tough and machines very nicely. Since it's typically available in black and white, and the rocket body is white, I opted for white for this set. I also make the base about 30% thicker to cut down on rail rash. That little bit makes a big difference. I also countersink the heads to conceal the fasteners. In this implementation, I am using #6 sheet metal screws, 3/4" long. They are drilled right into the centering rings:

button1.jpg

Compared to the stock buttons that come with the kit for reference:

button2.jpg

The rocket is already painted, all that remains is to put on the decals and seal it with clear topcoat, screw in the rail buttons and install the shock cord.

Thanks for looking.
 
Shellac is overlooked. Not a 'one size fits all' solution, but also a solution that works well in certain situations.

Thanks for bringing it up. I hadn't thought about using it related to rocketry.

Sandy.
 
Nice build so far! The IQSY Tomahawk is one of my favorite sounding rockets. So you applied epoxy to the fiberglass before it was on the tube? And then wrapped with mylar for a smooth surface? (curious, as I rarely use fiberglass).
 
Thanks. Yes, that's the method. I taped butcher paper out on the table, shiny side up (waxy really). Then arranged the glass on it and applied epoxy with a brush until it's thoroughly wetted and the same color. Then place the tube on it and roll it up. The fiberglass will overlap, but I couldn't feel a bump where that occurred. Finally roll the whole thing up in the mylar and work out the air bubbles. There is a good video on LOCs website showing them do it. That was my only experience, watching that and trying it out. Biggest take away is make sure you are not stingy with the epoxy. More is better as it has to conceal the weave of the fiberglass. I found that if you can still see the weave after the epoxy is applied you could use more.
 
Been a bit since I posted, the finishing parts of these kits seems to take the longest.

I painted the rocket with Krylon lacquer, the body is white, the nose cone red and one black fin. All then topcoated with clear Krylon spray lacquer. I love that stuff because you can recoat in 10 min or 10 hours, no problem. Unfortunately, doesn't come in a lot of colors.

The decals on this were a pain. Since they wrap up the sides of the fin about 1/4", I tried applying them in one piece. I got them on nice and straight, but no matter how careful I was, they would not stick in the area of the bend where the fin meets the body tube. I remedied this by figuring our how much would cover the tube area, then cut the wings and applied them separately as shown below:

decal.jpg

Applied to the rocket, at least the main section and one wing:

decal2.jpg

Pictures of the completed rocket:

rocket.jpg

Fin area with installed rail buttons:

fins.jpg

Aeropack retainer epoxied with JB weld:

areopack.jpg

I have a 20 foot kevlar 3/16" shock cord inside courtesy of onebadhawk. Still thinking about what kind of chute I want to make for this. Considering a 30" pulldown. Rocket with empty motor casing weighs a little under 2#. Will be launching as soon as the weather cooperates.
 
Nice, looks real good with the details.

I build the 1.6" LOC IQSY Tomahawk last year. Flew good until it found the top of a very tall tree this past June. Its still there.
Hope yours has better sense.
 
So finally flew this bird yesterday at the NOTRA launch in North East Ohio. I used an apogee deployment altimeter in the base of the payload bay and flew it with a Eggfinder Mini in the nose, both of which worked flawlessly.

Because the tube was so small, I had to get creative and stitched a 36” 8 gore chute out of the lightest material I could find. Felled seams all around with Kevlar lines sewed at each overlap. I used a chute release at 500’. Landed in plain sight 200 yards from the pad.

Attached is a short video I made up in IMovie.

Thanks to our own Andrew Kleinhenz for the narration and RSO duties.


View attachment trim.0C506CCD-4906-4195-A7AB-B45C4BDFFC8A.MOV
 
It was a near picture perfect flight! Definitely one of the high points of a really good day launching a whole bunch of rockets. And the rocket looks even better in person than it does in the pictures Pete posted.

John Bryan

Oh, and before somebody starts kibbutzing about the highway in the background - that’s the Ohio Turnpike and it’s roughly half a mile from our flight line 😎
 
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