10" diameter JayHawk

[SMR]

... the drogue pulls the dbag out. pulling the main out of the airframe. and releasing the main. letting the two half's come down separately. seems like it should work well.

I am a huge fan of the Defy Gravity "Tether". By far, one of the greatest products I have ever used, and I am very pleased to see Troy has them back in production and available here... (https://defyg.com/tether.html) The Tether's function is similar to the old Black Sky ARRD, which I first saw in use in the Gates Brothers' full size JayHawk. A video of her second flight (NSL, May 2002) is available here...

https://www.youtube.com/watch?v=xNIdalEHqR4

I have had 8 Tethered flights to date. The Tether worked exactly as advertised on each flight. I had 2 anomalies (attributed to my learning curve), neither of which resulted in a hull loss. On flight #1, the short length of shock cord between the Tether and the top of the deployment bag was a little too long, allowing the deployment bag to slide towards the open top of the payload bay. Airloads then pulled the main parachute out of the deployment bag while it was still in the rocket. Longer walk, but no damage. On the 5th flight, the payload bay, an unreinforced cardboard LOC tube, suffered a 6" long zipper at apogee. This "captured" the drogue shock cord, preventing it from pulling out the main deployment bag. Luckily, it was winter and the snow cushioned the higher descent rate (under a big drogue only). Other than the original zipper and some good scratching, no significant damage. The 10" Jayhawk has fiberglass reinforced body tubes, and will have a thick nylon strap (flex handcuff material) glassed to the body tube at the top to further reduce the possibility for a zipper event.

 

[stickershock23]

Thanks for that. it increases my confidence (I know the product works.. it how to use it I was curious about) I think I will order one today..

 

[SMR]

I finally have some time to catch up on a bit of the Jayhawk build. Last week we laid up carbon fiber and fiberglass cloth on side A of the revision 3 wing, and then clamped it in a homemade press to squeeze out the excess epoxy. The blue (painter's) tape is to protect the beveled leading edge of the wing from the overflow. When the entire wing is done I will run it back through the router to clean up the bevel as previously done with the winglets. I am always amazed that the fiberglass cloth becomes transparent when wetted with epoxy, clearly showing the opaque CF underneath it. The vertical lines visible on the photo are threads woven into this particular brand of fiberglass cloth, which is actually two layers of fiberglass sewn together, with the glass weave rotated at a 45° angle. This also tends to reduce it's drape-ability (if that's a word) and make it is a little easier to work with on flat surfaces.

 

[SMR]

This week we finished adding the carbon fiber and fiberglass layers to the revision #3 wing, and cleaned up and re-beveled the leading edges. The project bogged down a bit during this stage of the wing build, but I feel the added delay of about a month was well worth the investment as the wing is pretty stiff. The winglets are now attached, (although I will probably add brackets to strengthen the fillets on the interior seams), and the stainless all-threads that run through centering rings #2, #3, and the avionics bay are bolted on. Next step is slotting the lower body tube to fit over the wing tang. To get back on schedule, the body tube needs to be installed and glassed in by the end of May. Finally. as they are no longer necessary, the revision #1 and #2 wings were officially discarded.

 

[davalf]

Really neat project. I have become a big fan of the Jayhawk. I bet it will have one hell of a whistle after burntout. Looks great.

Dave

 

[SMR]

Sorry I haven't posted in a while. My next step is to glass the two body tubes, but I have to clear my workshop of a different project to do so. That one (an upscale Estes Death Star) is getting done and can be seen here...

https://www.rocketryforum.com/showthread.php?t=11861

When the last fin gets put on later this week, the Jayhawk moves back to the top of the list. I appreciate your patience.

 

[SMR]

My next step should have been to add 2 layers of fiberglass cloth to the 10" Polecat body tubes. Unfortunately, due to a lack of prior planning, I used the centering rings (needed to hold the body tubes properly on my "glassing pole") as shims to hold the motor tube / wing combination at the correct height to attach the winglets. (This is clearly evident in the first photo of post #34.) I didn't want to move that assembly until the brackets are installed, as the winglets are only held on at this point with 2 guide screws and are therefor a little fragile. So, the last few weeks have been spent cutting, drilling, and installing the aluminum brackets. I did not want to spoil the flat outside surface of the winglet with some ugly hex head bolts and washers, nor did I want to countersink flat head bolts into the winglet (not as strong), so a compromise was made here. Once again, McMaster Carr comes to the rescue! They provided a 1/4"-20 stainless bolt with an extremely large, low profile head, which provides the best of both worlds... the wood-holding strength of a fender washer and the almost-flush finish of a countersunk flat-head screw.

 

[dixontj93060]

Once again, McMaster Carr comes to the rescue! They provided a 1/4"-20 stainless bolt with an extremely large, low profile head, which provides the best of both worlds... the wood-holding strength of a fender washer and the almost-flush finish of a countersunk flat-head screw.

I've used low profile S.S. truss head screws from McMaster-Carr before--they are nice. I think the ones you have are even lower profile

 

[SMR]

I love these low-profile bolts! Nice brushed, stainless finish on them, too. Almost makes me want to mask them off instead of painting them with the rest of the wing. I sandwiched JB Weld under the brackets during installation, then tightened the bolts to squeeze out the excess. Now that the epoxy has fully set, I was directed to remove the motor tube / wing assembly from the dining room. (Actually, I was asked that several months ago, but was unable until she could stand on her own. Now she can.) This week, in addition to the move, I cut the 19" combination avionics bay / body joint from a full 48" length of coupler tubing. Starting with a X-Acto razor saw and quickly learning the futility of that, I finished the cut with a B&D fine tooth backsaw. Here are some photos of her present condition. At this point, she weighs 38 pounds and stands 75" tall, to the top of the avionics bay. The payload bay body tube is 46" long, 8" of which fits over the coupler and the 38" remainder to hold the 10' drogue and three 16' Spherachutes. The 33" exposed length of nose cone brings her total height to 146". (She looks crooked in the final photo, but that is just distortion from the wide angle lens used for the shot. I couldn't get far enough away to use a standard lens. Until I get back into the dining room.)

Tomorrow I start glassing the body tubes. I also need to fill the 2 per winglet "guide holes", and dremel off the extra length of 1/4"-20 bolt thread, flush to each nut, on the inside corner of the winglet-wing joint. More to follow.

 

[SMR]

1st of two tubes wrapped with 2 layers of 6 ounce fiberglass cloth using West Systems epoxy. I use centering rings in the tube to help it roll on the PVC pipe I use for a rotisserie, as well as to ensure the tube stays round during the process. Bare tube weighed 6 pounds 0.6 ounces. After glassing, it comes in at 8 pounds 4.6 ounces.

 

[SMR]

The second body tube was fiberglassed today. It looks a bit of a mess, the result of a completely unforeseen phenomenon. I had previously marked this tube where it would be cut to fit over the wing tang, using a permanent fine-tipped Sharpie, and knowing the fiberglass would be transparent after absorbing the epoxy. And I learned something new... West Systems epoxy dissolves Sharpie ink and made the lines bleed. So, after the epoxy cured, I moved the lines over about an inch and marked nice crisp new ones to be cut tomorrow.

Also on the agenda for tomorrow is glassing the 3rd tube. Why three tubes, you may ask? The body is 96" of body tube plus the 8" tail cone and 34" nose cone. Polecat tubing comes in 46" lengths, so I need a 4" slice of the third tube. I do have a use for the remaining 42" scrap, which will be documented here next year under the working title "Super Thumper".

 

[SMR]

First was the Omni Manufacturing "Tight Fit Drill Kit" mentioned in post #23. Second, a recent acquisition, is a Craftsman 3D sander. (Thanks to Tim D. for this discovery.) Allows you to sand rounded and uneven contoured surfaces. These have evidently been discontinued by Sears, so grab one when you can find it. Third is a Fiberglass radius roller. Used it for years as an auto body tool, even more useful in glassing rocket tubes. It is a ridged roller, which holds down the fiberglass cloth while forcing air bubbles out of the epoxy.

 

[dixontj93060]

First was the Omni Manufacturing "Tight Fit Drill Kit" mentioned in post #23. Second, a recent acquisition, is a Craftsman 3D sander. (Thanks to Tim D. for this discovery.) Allows you to sand rounded and uneven contoured surfaces. These have evidently been discontinued by Sears, so grab one when you can find it. Third is a Fiberglass radius roller. Used it for years as an auto body tool, even more useful in glassing rocket tubes. It is a ridged roller, which holds down the fiberglass cloth while forcing air bubbles out of the epoxy.

Hey posting again--great. Still hoping to see this "work of art" flying at MWP8!

 

[SMR]

Still hoping to see this "work of art" flying at MWP8!

I am running the project much as the folks at NASA do... behind schedule, over budget, and with the constant reminder that the person with the checkbook might cancel the program at any time.

 

[Brent]

I am running the project much as the folks at NASA do... behind schedule, over budget, and with the constant reminder that the person with the checkbook might cancel the program at any time.

Now that is funny:clap::roll:

 

[Pem Tech]

Incredible attention to detail...

Your Engineering Fu is strong...

 

[SMR]

Today was body tube wing slot day. I started by checking my measurements and marks by physically placing the body tube on top of the wing / motor tube assembly. Everything seemed to line up, so I hauled the body tube outside and started to cut. This took the whole day. Wow, am I a bad judge of time or what! (I never did get to glassing the third body tube.) You'll notice in the second picture it is just beginning to get dark out. I finished up by trial fitting the pieces together. Tomorrow, in the light of day, I will put the top tube and nose cone on for her first real photo op.

 

[Rocketman248]

Oh, man this thing is looking sweet!

 

[SMR]

I took some time today to assemble the 10" Jayhawk for the first time. (the tailcone is just temporarily stuck on here, held in place loosely by the aft centering ring.) It was such a nice day, after storms last night, that I brought the whole fleet out. Kelly, 53" tall, is included for size reference. Here, from left to right, are...

Polecat 5.5" Jayhawk - 54mm (flown x 2)
Crayola Jayhawk (Crayhawk) - 38mm (flown x 1)
BT-60 Jayhawk (purple) - 18mm (flown x 6)
BT-60 Jayhawk (orange) - 24mm (in construction)
10" Jayhawk - 98mm (in construction)
Hershey's Strawberry Syrup Jayhawk - 38mm (flown x 2)
BT-5 Jayhawk - 13mm (flown x 4)
BT-20 Jayhawk - 13mm (flown x 6)
Polecat 4.0" Jayhawk - 38mm (flown x 3)
Hershey's Chocolate Syrup Jayhawk - 38mm (in construction)
Madcow 2.6" Jayhawk - 29mm (flown x 1)

Missing from the group picture is my Fliskit BT-70 ACME Jayhawk (flown x 2), which was lost in tall grass at a low power launch on June 5th.

 

[judo]

Looks like you buy orange paint in bulk.

 

[DANLK66]

Great picture Sather! It wont be long now.

 

[SMR]

Looks like you buy orange paint in bulk.

I do. My earlier Jayhawks were painted in Plastikote Chevy Engine Orange enamel, a high temperature paint with a nice reddish-orange color. I had some cans left over from my hot rod days, but it is pretty pricey to get more. ($9.99 per can plus shipping!) So I switched to Valspar orange, readily and cheaply available from Lowes. Great paint... very fast drying, no runs, no orange peel, and a nice deep gloss. Got to be careful with the second coat, though. The instructions say "before 4 hours or after 36 hours". I lay it down pretty thick to get a high gloss, so it takes longer to dry all the way through. A week between coats works better than 36 hours. I used this paint on my King Tut's Pyramid, one side at a time. The second coat on the first side attacked the first coat and heavily crinkled it. I liked the effect, so i did all four sides the same way. It wouldn't be good look on a 3FNC, though. (Or a 2FNC).

 

[dpower]

...Missing from main picture is my Fliskit BT-70 ACME Jayhawk, which was lost in tall grass at a low power launch on June 5th.

Sather, can you put this pic in the Spitfire Photo Collage thread? It was a great design, I'm really surprised (and bummed) we didn't find it with all that tromping around...

https://www.rocketryforum.com/showthread.php?t=11348

 

[kelltym88]

a recent acquisition, is a Craftsman 3D sander. (Thanks to Tim D. for this discovery.) Allows you to sand rounded and uneven contoured surfaces. These have evidently been discontinued by Sears, so grab one when you can find it.

I picked one up on ebay for $5. Love it, love it, love it. Yes, Thanx Tim D. :clap:

 

[SMR]

can you put this pic in the Spitfire Photo Collage thread? It was a great design, I'm really surprised (and bummed) we didn't find it with all that tromping around...

Wow, I didn't even know there WAS an ACME Spitifre thread. Thanks for pointing this out. I just posted some pictures of her there. I haven't given up on getting her back, so will probably stomp around out there a while next sod field launch, too. Probably too soggy to fly again, but she would like to be in future Jayhawk family album photos.

 

[SMR]

I am going to add this to the Jayhawk build thread as I have had a few PM's on it, so others may find it interesting. On my altimeter skids, I use POPO switches (Push On Push Off) from GC electronics, one per altimeter. They are attached to the skid to minimize re-wiring when switching altimeters between rockets. I have vent holes in the rocket, lined up with the end of each switch, so it can be armed on the pad with a short length of dowel. A link to GC is here...

https://www.gcelectronics.com/index.asp

https://www.gcelectronics.com/order/SubCatPDF/pushbuttons 298-305.pdf

The only current link I could find in their online catalog is for a DPDT switch, part number 35-491. (Scroll down to it from the 2nd link above. It is on page 300 of their catalog). I am using 4PDT switches, which allow me to combine the squib shunt function with redundant power functions on the same switch. (i.e., the e-matches are shorted when the power to the altimeter is off, and not when the altimeter is on. The "ON" switch is doubled, to reduce switch failure anomalies.) One less thing to mess up. These GC switches have part number 35-492-BU on the packaging. (The BU signifies they were purchased in "Bulk", and then re-packaged individually.) I bought mine from "Jaytronics", an electronics supply store in Rockford, Illinois (https://www.jaytronics.com/products.htm). You can contact them at 866-965-6775 or by email at [email protected]. Very helpful people. Ask for Andy.

 

[SMR]

To err is human... This was the first launch of this rocket AFTER switching from external key switches to internal POPO switches. I had previously broken a wire on the back of the external switch (inside the avionics bay) while inserting the altimeter skid, which I couldn't repair in the field. When I later rebuilt the skid with on-board switches, I left the dead external key switch in place on the avionics bay band to fill the hole. It also was a nice place to hang Remove Before Flight flags to remind me to arm the electronics. Luckily, I DID remember to arm them. However, I needed something to remind me to remove the Remove Before Flight flags! (The flag survived the otherwise uneventful flight.)

What I do now... I realize there are a bunch of ways to do pretty much everything, so I offer this up with the only testimonial being "it works for me". I always tape my primary igniter to the side of the rocket for the journey from my prep table to the RSO to the pad. I made up some brightly colored, laminated tags that say "arm electronics before inserting igniter". I keep them in my igniter box and add one to the masking tape when I tape the igniter on. It gives me one last reminder at the pad to do things in the proper order.

 

[SMR]

Rail button screws (but not rail buttons) are installed, and winglet guide holes are filled. The payload section has been removed again as I now make forward progress on wing fillets. This is basically a 16 step process, four procedures repeated four times, rotating the rocket assembly 90° between each step, with a few assembly/disassembly steps thrown in for confusion. note - this is just a summary... (a) Lay down a small exterior fillet of JB Weld. This holds the body tube in position* when I remove centering rings (one at a time) for access to the interior of the body tube, and prevents epoxy from the interior fillets leaking out onto the wing. Repeat for remaining exterior seams. (b) Mark the position, then remove the aft centering ring. Apply fiberglass tape to lower half of lower body tube, along wing-body seam to spread bonding area up side of body and along wing tang. Take car to NOT get epoxy into area that would interfere with replacing aft centering ring at completion of step. Add a generous interior fillet of West Systems 105 epoxy, 206 slow hardener, and chopped carbon fiber. Imbed hardwood dowel into the bead and smooth out the epoxy. Repeat for remaining interior seams. (c) Tip rocket vertical, nose down. Apply fiberglass tape and epoxy fillet around perimeter on the bottom of centering ring #2. Allow to cure. (d) Tip rocket vertical, nose up. Apply generous bead of thickened epoxy around inside perimeter of body tube and outside perimeter of the motor tube, where you marked the aft ring. Reinstall aft ring, forcing fillets to form as you move it into position. Allow to cure. (e) Tip rocket vertical, nose down. Apply epoxy fillet around inside perimeter of body tube and outside perimeter of the motor tube on the bottom of centering ring #1. Allow to cure. (f) Install centering ring #0, thrust ribs, and tailcone. (g) Tip rocket vertical, nose up. Mark the position, then remove the forward centering ring. Foam tailcone. (h) Repeat interior fillet procedure in upper half of lower body tube, around top of centering ring #2 and along wing. (i) Replace forward centering ring as in steps (d) and (e). (j) Apply fiberglass tape and exterior fillet along entire length of wing to body joint.

* The body tube is also thru-bolted to motor mount via rail button screws into hardwood blocks on centering rings.

 

[SMR]

I started the first interior fillet today. Photo is of the interior seam between the body tube and wing tang. Blue tape is to protect the area of the aft centering ring from epoxy drips. I was pleased with how tight a fit the body tube made with the wing assembly. No gaps at all, which is surprising as I cut the very long slots in the body tube by hand with a Dremel tool. I didn't get pictures of the glass and epoxy going in, as I was working against a time limit (epoxy) and got a little epoxy on my hands, so didn't feel comfortable touching the camera for a while. As I fine tune this procedure (over multiple times), I should be able to document it.

 

[SMR]

Three of the four lower interior fillets are now done, and I got my timing down to where I could take pictures between steps without cooking the epoxy. (Not the best photos but they give an idea of the sequence.) The first attached photo shows the interior tube and tang wetted with West Systems epoxy, and the fiberglass cloth laid in position. Second photo shows the cloth fully wetted, with the excess epoxy forming a fillet in the valley. The third photo shows the 1/4" dowel imbedded in the epoxy fillet. The fourth shows the epoxy/chopped graphite roughly spread into position. A piece of waxed paper was placed over this, and with a paint brush taped onto a three foot stick, smoothed into something that resembles a fillet. The fifth photo shows the final result after the wax paper was removed. One more aft fillet to go and I can reinstall the aft centering ring and start working on the tailcone.