IQSY Tomahawk Sport Scale Bash

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Bruiser

Well-Known Member
Joined
Jun 7, 2018
Messages
1,593
Reaction score
862
I have decided to try rocketry again after a 40 year hiatus. I wanted to keep the first rocket kinda simple and I wanted to try to purchase everything locally. It turns out the only place that actually sell kits in town is Hobby Lobby but they did not have a scale kit in stock so I have decided to bash an Estes Star Orbiter into a IQSY Tomahawk. I spent a few days last week researching how to go about that and I have come up with a plan. I started cutting and gluing this morning.

First I had to cut one of the tubes down and make the slots for the fins. The tube did have slots cut for the Star Orbiter but unfortunately, only for three fins. A piece of angle aluminum and a single edge razor blade worked great.
Slotted Tube.jpg



Next I had to decide how to glue in the centering rings for the motor mount tube. I decided to glue the top ring inside the tube first so I need to come up with a "tool" to push the ring up in the tube squarely. I went out to the tool box and this is what I found:
Insertion Tool.jpg



I carefully measured where my ring of glue needed to be. I marked the distance on a Bic pen and after several transfers, got the ring where I needed it, then I pushed the ring into position with the centering tool.
Insertion Tool At Work.jpg



I used the end of the pen to smooth out the glue and I think I came out nice.
Top RIng Installed.jpg



Next step will be to install the motor mount tube into the body. Need to wait for the glue to dry :)

More to come later,
-Bob
 
Last edited:
The glue dried so next was to install the motor mount tube in the body tube. I ran some glue around the upper part of the motor tube and then using the same method as before I ran a bead of glue around the inside of the body tube where the middle centering ring would be. Working as fast as I could I slide the motor tube up in the body tube until it was at the correct depth. Then I ran bead a glue around the outside of the motor tube and the inside of the body tube and installed the lower centering ring. I set the tube aside to dry.

Body and Motor Tubes Joined.jpg


So while it was drying I decided to start on the fins. I cut them all out using the template I had made with a razor blade. I was surprised that worked on basswood. It did take multiple passes but I got it done. I stacked tem together with a few drops of CA to hold them together and sanded them all to shape. It was during the sanding I noticed that the grain was not orientated correctly. It was running with the body tube instead of the leading edge. After I finished sanding the outline I separated them with some trepidation. Would it be just the one, or would there be more? Turned out to be just the one.

Bad Fin.jpg


I cut another and used the bad fin to match up the outline. Then I drew my guide line for sanding the leading edge to a point and went to town making dust. I got a nice, straight line with my permagrit sanding tool and here they are ready for paint.

Four Fins.jpg


Of course, I just had to stick them in the slots for a visual. I positioned the mount motor ring and sized the tabs so that they would fit together, sorta interlocking in a way. The tabs will support the motor mount tube and the centering rings will help support the fins.

Body with Two Fins.jpg

Coming from the R/C world I was thinking of using water based polyurethane as a sealer but I keep reading about thinned out wood putty. Any opinions about that?

On to joining the body tubes now.

-Bob
 
Be sure to use properly proportioned screws if you elect to add them. The NARTS scale pack actually includes the dimensions for the countersunk and cap screws. What is the body diameter?
 
The body diameter is 1.66 inches. I found a rocket blog where the fella built an older IQSY Tomahawk kit with a 1.33 tube. He had a jpg to print decals off from that he offered on his blog. I think I am going to go that route and slightly enlarge the jpg when I print it.

I didn't get much done today. Mostly worked on fabing up a baffle. I'm using a 3" piece of the body tube I cut off and two plywood discs. I have a short length of dowel I am putting in the upper disc to give the eye hook plenty of material to thread into.

More to come tomorrow,
-Bob
 
CWP Fin.jpg
I applied the CWP to the fins and let them sit for a hour or so. I stacked them with layers of wax paper between them and weighted them down with a book. I thought an hour would be enough for them to dry but they were flexible so I put them back in the stack and let them sit over night. They were good to go this morning and I got them all sanded. I taped off the glue areas and sprayed the first coat of filler/primer on and they look pretty smooth. Now to be patient and let them dry for the wet sanding. Not really sure why I spent the time taping them off as most of the primer will be sanded off...

CWP Tube Joint.jpg
I joined the body tubes and applied the CWP to the joint and set it aside to dry. It didn't take long before I was able to sand the joint. I masked off the fin areas where the glue filet will go and sprayed a nice coat of filler/primer on. I can see I am going to need to do a little more blending in the tube joint area. I didn't really see any spirals though so that is good.

Ejection Baffle Coated.jpg
I worked on coating the inside of the baffle tube assembly that I built. I think I'll do one more coat before I assemble it because once it's together, that is the way it'll be. I can't imagine it'll be that easy to remove if I ever needed to work on it.

Time to sit here and let paint dry then the fun of wet sanding...

-Bob
 
Last edited:
Today I had a little scare. I had primered the body tube and I was wet sanding it. It was going well then suddenly I started feeling bumps under the sandpaper. Turns out I had scratched the surface of the cardboard and it was starting to swell up in spots. I set it aside and allowed it to dry. Then I shot on another coat of primer and dry added it to take off the fuzzies. After a few more coats it is good to go. No more wet sanding body tubes for me.

Buffer Upper End.jpg


I also got my ejection baffle assembled and ready to go in.

That's it for today,
-Bob
 

Attachments

  • Buffer Upper End.jpg
    Buffer Upper End.jpg
    21.6 KB · Views: 76
Last edited:
Thank you so much for your reply. There's been all these views and only you have posted anything. I wasn't sure if that was a good sign or a sign that I'm doing so bad no one wanted to post for fear of opening a can of worms :)

Not much going on today but I have got two fins epoxied to the engine mount. I hope to get the other two on as well.
Two Fins.jpg

Thanks,
-Bob
 

Attachments

  • Two Fins.jpg
    Two Fins.jpg
    54.3 KB · Views: 70
Last edited:
I did get all four fins glued on yesterday. I noticed there was some epoxy on the body tube near the slots for the fins that had to be cleaned off before I could run some nice fillets of glue where the fin goes thru the body tube. I guess it scrapped off the fin as I was inserting them thru the body tube. I was so worried about the glue setting before I had them in position that I did not take much time between wetting them in place and putting the fin guide I cut out of cardboard on. Once that was on it was hard to see anything... Anyway, a little scrapping with a razor blade and some light sanding and it was time to run the fillets.


Fin Fillet.jpg

So all the fillets are done now. Next is to attach the 1/4 launch lugs. I guess I'll sand them a little and coat the inside with some CA before attaching them with 5 minute epoxy. It doesn't seem like that will be very strong but I guess that'll do. I'll sand/scratch up the body tube before gluing them on to get a good bond.

-Bob
 
Quick question- have you checked stability on this? I'm guessing you'll be fine but it never hurts to check. Based on my 2.2" version, I'd estimate CP about 30" from the tip of the nose, just above the fins. Does that seem right?
 
I did do an analyses using a program someone recommended and the stability looked better using the "D" engine than it did with either the "E" or "F". The Star Orbiter (donor rocket) is listed as over stable. The biggest change I have made is to shorten the body tube from 35.5. to 27.5 inches, but that is still plenty long. Oh, and I did add one more fin (was three, now four) and changed from balsa to basswood. Another Oh, I did build a buffer tube that will be installed in the body tube about eight inches from the nose cone.

When the rocket is done I will cut out the cardboard template to find the CP and then check the CG with the string for each engine. I have no problem with adding weight if I need to. I'm not going for an altitude record :) Just a sport scale rocket that is fun to launch.

Now you did it talking about the CP being 30" from the nose. Seemed kinda far to me so I just put the nose cone on for the first time and the rocket has come out to be 36.75 inches tall.
First Time Together.jpg

Bob
 
I did do an analyses using a program someone recommended and the stability looked better using the "D" engine than it did with either the "E" or "F". The Star Orbiter (donor rocket) is listed as over stable. The biggest change I have made is to shorten the body tube from 35.5. to 27.5 inches, but that is still plenty long. Oh, and I did add one more fin (was three, now four) and changed from balsa to basswood. Another Oh, I did build a buffer tube that will be installed in the body tube about eight inches from the nose cone.

When the rocket is done I will cut out the cardboard template to find the CP and then check the CG with the string for each engine. I have no problem with adding weight if I need to. I'm not going for an altitude record :) Just a sport scale rocket that is fun to launch.

Now you did it talking about the CP being 30" from the nose. Seemed kinda far to me so I just put the nose cone on for the first time and the rocket has come out to be 36.75 inches tall.
View attachment 356004

Bob

The CP is really far back on this design- should be an inch or so above the fins? 7" from the bottom sounds right.

I'd trust whatever OpenRocket/Rocksim tells you- this is a pretty standard design (nothing it can't sim) so it should be good. The cardboard cutout method works but tends to be really conservative- it should be plenty stable with most motors.
 
So open rocket shows these measurements

D12
CG 62.4 cm
CP 76.1 cm Apogee 62.5m

E16
CG 65.5 cm
CP 76.1 cm Apogee 117 m

F15
CG 67.0 cm
CP 76.1 cm Apogee 238 m

I can't figure out how to see this in inches. The rocket is about 94 cm long. It seems the "space" between the CG and CP varies about 3 3/4 to 4 1/2 inches or so. Should that be fairly stable?

Apogee is the height, correct?

Thanks,
-Bob
 
Last edited:
Progress has been made. Yesterday I painted the body tube white but I ran into a problem with the paint splattering. The can of paint almost got launched into orbit but then I saw that the finger tip on the glove I was wearing was hanging over the spray nozzle. Once enough paint had collected, it would drop off into the paint stream and cause the splatter. So I let it sit overnight and did some wet sanding this morning and tried again. This time I was mindful of the glove and I like the results :)
White Body Tube.jpg

So now I need to paint one fin black. I have a can of black paint but it is not the same product as the other paints I have used so far. I have been using Duplicolor perfect match and I like the results. The only thing I don't like is the price, eight bucks a can. I used the whole can of white to paint the body tube over the gray primer... I don't really want to spend another eight bucks for a can of black, but then again I don't want paint mismatch problems either. Guess I'm springing for another can of paint :)
Paints.jpg


Need to go buy some black paint now,
-Bob
 
Ok, well I had a little set back. I intended to make some stickers/decals for some of details. I purchased some Avery clear sticker paper and printed out the details. I cut out the row of bolts that go on the nose cone and applied them. Right away I could see that it was really not clear as you could barely see the red through the sticker. So I peeled the sticker off and peeled off some paint too-ARRGH!

I guess for future builds I will have to find a paint that sticks to plastic better. I did sand it with 400, applied primer and then paint so that is what I did again. Nose cone fixed...

As for the black paint, I did manage to pick some up while out on errands. Unfortunately they did not have any "GM" blacks :( so I had to settle for a universal black :) . I have the fin painted and after the problem with the stickers, I painted the top band of black on the body tube. I think I am going to use some paint to simulate the bolts and I will print out the telemetry section on paper, glue them on and then clear coat.
Black Fin.jpg

Guess I need some clear coat now. I use to use Krylon crystal clear on my RC aircraft but I guess I should stick with the Dupicolor on this one. Gonna be looking for a new brand of paint for the next project though because at nine bucks a can I now have thirty-six, soon to be fourty-five dollars in paint for this 3 color scheme on a twenty dollar rocket
 
Last edited:
Been busy again. Tried stickers for the telemetry section and didn't like the results so I decided to paint it on. It's Testor's silver enamel paint and a white Sharpie marker.
Telemetry 1.jpg

Telemetry 2.jpg

Then I struggled over using stickers or glueing on fin (?) doublers. I finally decided to go the route of painting them on so I am using a fine tip marker and the same Tester's silver paint.
Fin Can.jpg

Maybe not entirely scale but I think it's a good representation.

Thanks for looking,
-Bob
 
So I decided to work on the 24 to 29mm adapter. Since we don't have a hobby store and I didn't want to wait, I bought a Estes Generic from Hobby Lobby to use for parts. I cut the body tube to the same length as the engine tube. Then I also cut eight 1/4 sections off the body tube to make rings. I also used the engine hook. I installed the engine hook and captured it with the rings that I cut. The adapter still fit a little loose in the 29mm tube so I added a layer of printer paper and now it fits nice. I made a "capture" ring out of some 1/8" ply with my dremel and permagrit tool and epoxied it on. After everything sat for awhile I thinned out some epoxy and coated the outside of the assembly.
24mm Adapter.jpg


Next it was time to see if it would really work so I inserted it in the mm tube
24mm Adapter Insert.jpg


The final thing was to see if I could capture it with the nut:
24mm Adapter Installed.jpg

And it seems to fit perfect!

I guess the only thing left now is the recovery system. I have the baffle made but it's not glued in yet. I haven't found any Kevlar string locally so I'll have to order it. I am waiting on the baffle install until I can attach the string easily (for the first time anyway).

-Bob
 
Back in the day when dinosaurs roamed the earth and I used to work for AeroTech a little over 25 years ago we built a pre-production IQSY Tomahawk that we flew in competition with a hand-turned basswood (or some other kind of hardwood) ogive nose cone. Still have it in storage in the garage. This was in the days before RockSim/OpenRocket. Flew straight as an arrow.
 
The recovery system is full install now. I posted a thread over in the recovery system area for help on that.

I thought that was it but it turns out I still need to epoxy the motor retainer to the tube.

I need to decide on the initial flight engine and find someone with a launch pad (etc) that can help me get it in the air.

Thanks again for everyone's help,
-Bob
 
Thank you. The rocket is done now and I just need to find someone in the Alamogordo area that can help me with launching it. There was a club here so I'll have to see if it's still active.
Finished.jpg

It's pretty simple compared to Neil's IRIS-T but since it was a bash I had a few things to learn. There were quite a few mods to it and quite a few things have changed since building C powered rockets as a kid in the seventies. Looking forward to getting it in the air.

I've got an 7240 Honest John waiting in the wings that I probably will modify in some way. Also have a 7260 Protostar that was clearance priced that I couldn't walk by. It's telling me that it's some sort of sport scale project but I'm not sure what yet :)

Thanks again,
-Bob
 
I'm resurrecting this old thread because I did something today I haven't done in a very long time. Not since I was a young, young teenager. I launched a rocket!

It was the I.Q.S.Y. Tomahawk I built n this thread. I flew it twice on Estes D12-5 motors.

The first flight was very cool. Experts say it probably hit about 450 feet. The chute deployed a little early and I got a zipper about 1/8" long. I was a little worried about a second launch due to the zipper but I decided I already had one repair and I could do a second repair at the same time so I loaded it up again. The second launch went a little higher and the chute deployed much later than the first flight. In fact, you might have heard an "oh-oh" come out of my mouth just before it deployed shortly after apogee. It was a perfect flight! Totally awesome!

I met a lot of nice people at the launch field of the SMRA in Alamogordo. Bill Hanson was very helpful in getting me going and Thomas Kindig Helped me at the inspection table. Met a lot of other people as well and one gentleman showed me the technique for packing the chute and laundry. SO sorry I can't remember his name. I just met so many nice people.

Here's a picture on the launch platform. I tried to get a video but I guess I don't know how to work my phone :(

IQSY Tomahawk on Launcher.jpg

Next month, I think I'll be making a similar post on my Honest John thread.

Thanks for reading,
-Bob
 
Hi Bob,
That was a very nice IQSY today! I'm the guy that helped with the 'chute packing and getting the rocket on the pad for the first flight. Also, I think your rocket was the first one fired from my wireless launch controller other than my own personal launches.

My Avatar here is my 6" dia IQSY Tomahawk on an AMW M skidmark motor. Here are some photos from the build in 2002, L3 cert, and the skidmark flight in 2010. https://photos.app.goo.gl/jr4jLEJG3lhhyGr12

Hope to see you out at the launch again. 1st Saturdays in Las Cruces, and 3rd Saturdays in Alamogordo. Next month is a 2-day launch in Alamo.
 
I was looking for you and Bill when I was getting ready to leave today to thank you but I didn't see you. You might have still been out retrieving Bill's rocket.
Thank you for the compliment on my rocket. I didn't really think I was ever going to fly it. In a way, I didn't really feel the need. I got a lot of enjoyment out of doing the research on the Tomahawk and with building it. But I have to tell you it was real exciting to see it in the air! I have a heavily modified Estes Honest John that I hope to bring out next month now!

One other thing is that I thought I would be happy just sticking to 400-500 foot flights but after seeing that Star Orbiter (that is the kit I bashed into my Tomahawk) fly with an "E" motor I find myself thinking about trying an "E" in mine. Just a simple thing of pulling out the adapter and the "E" will slide right in :)

That is quite a photo of your Tomahawk! The flame and smoke trail look awesome! I did not get any video of my launches :( I'll have to get a lesson from my wife before I go to the range next month :)

Thank you for your help today. I hope to see you again next month.

-Bob
 
Back
Top