Monday, October 31, 2011

Quest Striker AGM Build Part 3 Nose Cone

I jumped ahead to the nose cone.
Before gluing, sand off the molding flash especially on the side without the alignment pins.
I've had some experience with the old Nike Smoke two-piece cone before.

To see one way to fill the seams and molding dimples,
Check last year's Nike Smoke post HERE

After the two sides were glued together, medium thickness CA glue drops were set into any concave seams and dimples.

After it thoroughly dries, the rasied CA is sanded to the surface of the cone.

Quest Striker AGM Build Part 2 Engine Mount Adapter

Step 1 is a typical engine hook install.
Slit the tube 1/4" from one end. Insert the hook and wrap with tape in the middle.
I substituted a 2 3/4" length of BT-20 for the thin Quest yellow tube.

Check the first photo. The interior ribs extend past the top and bottom of the adapter a little bit. Sand the top and bottom flat so you'll have a better flat gluing surface for the centering rings.

After the rings were glued in place, the adapter assembly wouldn't slide into the 35mm tube easily. Sand the ring edges to the diameter of the upper and lower adapter ends.

The smaller, lower ring will be exposed.
The brown ring is a little rough. I hardened and sealed it for smooth sanding by applying a coat of CA brushed on with a Q-Tip. A little sanding with 400 grit will leave a smooth surface for paint later on.

There is an "gotcha" in step 3. With a wrap of tape around the engine tube and over the hook, the tube won't slide into or past the upper centering ring.
I removed some tape and widened the inside ring diameters for a better fit.
I'd recommend cutting a notch for the hook, especially on the lower ring. Otherwise, there wouldn't be enough hook movement to allow an engine to be inserted.

Sunday, October 30, 2011

Model Profile Dr. Zooch Atlas Agena

On the Zooch website you are reminded:
"This kit is NOT for beginners- nor is it for people who don’t bother to read the text."
The cardstock flares around the nozzles will take a little more time but are doable.
I've flown this one many times with great success.
The flame fins were painted with white and yellow spray cans. I left off the orange this time after looking at NASA launch pictures. Real engine flame goes from bright white, then a little yellow to gray smoke.

Quest Striker AGM Build Part 1 Parts

Here's all the parts, right out of the bag.
The Striker AGM looks to be a great design, perfect for demos and small fields with a B6-4.
The 35mm tube is long, just a little over 18" long.
The blue engine block isn't shown, it was found inside the yellow engine tube after the picture was taken.

The pieces of interest:
The engine hook will be replaced with a spring steel hook made from the metal strip inside an old windshield wiper blade. This hook included with the kit bends easily. Looking ahead at the engine mount, the hook will need to be flexible.

The yellow engine mount tube is a little thin. It has a rough finish and would require a smooth surface where it's exposed out the back of the tail cone. I'll substitute a BT-20 tube.

The centering rings seem thin, but should be fine the way they are assembled in the mount.

The tail cone has ridges on it. There is four recessed lines used for fin alignment.
The thickness of the ridge around the shoulder is inconsistent, thinner on one side. This might effect the fin root edges contacting the body tube.

Saturday, October 29, 2011

Engine Hook Idea from Greg Poehlein

Recently a member of the was asking about an engine hook that seemed too short for a newer Estes E engine.
Greg Poehlein responded back with a great new idea of putting a reverse bend in the top of an engine hook.

Thu, October 20, 2011 1:15:23 AM[OldRockets] Re: Estes Engine Hook
From: Greg Poehlein
If you are planning to use it in a rocket with a body tube of BT-55 or larger, you can still use these hooks. My suggestion is to put a motor block in the tube at the depth you want for an overhang. Then, bend the top end of the motor hook AWAY from the motor tube at a 90 degree angle. Glue the centering ring just behind the hook, so at ejection, the ejection charge will be pulling the motor hook against the centering ring between the motor tube and the body tube. For that matter, you could do the same thing with a standard (2.75") length motor hook as well. Good luck with the build.

Here's what one of these hooks could look like if used on a standard 18mm engine mount tube.
While Greg mentioned using this hook in a BT-55 or larger, the hook as shown (with a shorter top bend) could fit into a BT-50 sized tube.

The bend on the right side goes under the nozzle end of the engine. The upper (shorter) bend faces away from the mount and and would sit over the top of the upper centering ring.

The engine hook from the side. Notice how the upper bend of the hook faces out and goes over the top of the upper centering ring.

With a "shotgun" ejection charge any movement of the hook is against the top centering ring, not pulling down inside a thin walled BT-20 engine mount tube.

In this example, the upper outward bend of the hook is shorter so it won't overhang the centering ring diameter.

Viewed from the top, you can see the engine block (or thrust ring) in place.
The thrust ring keeps the engine in place during the boost stage.
The lower and upper reverse bend in the engine hook keep the engine in place at ejection.

A simple, brilliant idea. Thanks Greg!
Check out Greg's Project Paper on TRF HERE


Yeah, I know - it's a green bat!
I don't care, it was just built for fun, something different at the group launch.

Just over 27" tall and 3.75 oz (no engine)
It'll fly with B6-2, C6-3 or C6-5 engines.
It should be a big hit with the kids.

The Batter Up has been flown twice since the build was finished. Once with a B6-2 at the schoolyard and with a C6-3 at the last Orlando ROCK launch on October 1.
It's goofy and stable. At the ROCK launch I had two misfires or as the RSO said: "Two strikes!" It did fly on the third attempt. That ball is hard to find in tall grass.

Friday, October 28, 2011

Cleaning Up Post Launch Part 3

An Email from Andrew Ballard:

Another way to keep things looking clean is a can of dry lube. Especially if you start when your parts are new. The idea is similar to using Pam cooking spray on pots and pans.
I use this industrial type on a 1010 rail launcher. It goes on dry to the touch, non greasy. Makes it very slippery, withstands high temperatures, and black soot wipes right off.

Remaining Teflon will wash off easily, then re-spray again the next time out.
This one is a little expensive, around $9.00. However Home Depot has an off brand around $4.00 I was going to give a try.

Of course if you were using a Blast! Deflector with a "Raise" Spring these may reduce the degree of post launch maintenance. Maybe we'll see them in action sometime in a school yard launch entry.

Thanks Andy!
I still use my original Odd'l Rockets Blast! Deflector, Raise Spring and Adeptor at every schoolyard launch. The Blast! ceramic deflector directs most of the flame and residue away from the flat metal disk below it.

Batter Up Build Part 9 Contact Cement and Fins

Here's the first fin on the handle of the bat.

Remember, for contact cement to work, both adjoining surfaces get a brushed coating. Let the wet cement dry until it is dull, it should be dry to the touch.

Position carefully before pressing the parts together. The quick, strong grab will surprise you!

It's pretty apparent by the picture why I used extended tabs to glue on the fins. They probably wouldn't stick with any other glue except for the contact cement.

These fins do flex a bit from the root edge but are plenty strong for flight. The flex (and give) may help soften a hard landing.

The launch lug standoff was also glued with contact cement.

Here the excess glue is being rubbed off with a sharpened dowel. It'll take a few minutes to roll off the excess glue into little balls, but it will come off.

The lug standoff contact cement joint is very strong!

Thursday, October 27, 2011

Coupler Tip from Jeff Gortatowsky

This was one of those things I never thought about, but is important especially with the new (tight fitting) red Estes couplers and quick grabbing glues.

TIP: Put several wraps of tape around the coupler where it should stop. Then twist in with one motion. The tape lets you get aggressive and still not go too far if it grabs a little and you have to push.

Jeff Gortatowsky
Redondo Beach, CA. NAR 70988

Jeff later wrote:
I believe it would work fine for all couplers but with low tack tape or very narrow strips. You don't want to lift any of the paper off the coupler taking the tape off. So you need to be careful or wind it on the coupler such that pulling the tape off does not lift the end winding of the coupler.

Thanks Jeff!
That's a good point about not pulling off a layer of the coupler when removing the tape. You can reduce the tack of the masking tape by pressing it on your jeans and pulling it off a few times. This leaves small denim fibers on the tape and reduces the stickiness.

TIP: The newer RED Estes couplers have a tight fit right out of the bag.
Sand them until you get a smooth slip fit in the tubes you are joining.

TIP: Titebond II and the new (Stronger Formula) Elmer's White Glue can grab quickly, sometimes before the coupler or engine mount is slid into it's final position!
When in doubt, mix up some Epoxy for gluing in engine mounts and couplers.

Batter Up Build Part 8 Contact Cement and Fins

After the fins are dry, the overhanging balsa was trimmed off.

Here's the fins ready for gluing.
I'll be using contact cement to glue the fins to the plastic bat handle.
If you've never used contact cement be ready for a quick grab!

Contact cement is applied to both surfaces being joined. In this model, the glue tabs on the fins and on the bat handle.
Wait for the glue to thoroughly dry on both parts being joined.

Even though the glue is dry to the touch, when both parts are joined, you'll get a bond that is hard to pull apart!
Be sure your fin is aligned before allowing both glued surfaces to touch.
This contact cement is pretty old and brown. When new it is a lighter yellow color.

Using the brush on the glue bottle cap, it was applied to the tab flap of the fins.
A wide line of glue was also brushed on the fin lines drawn on the bat handle.
Try to keep control of the cement, it'll want to go everywhere!

It does clean up easily so don't worry about any extra strings of glue on the surfaces.

Wednesday, October 26, 2011

LAUNCH! Soccer Field October 25, 2011

I was cold this morning, I should have grabbed a jacket.
No wind at ground level, the palm trees were still.

A good first flight and test for the system is my smaller UP! CUP flown with an A10-3t.
At ejection this one falls faster than the larger Odd'l Rockets kit. Stable, noisy and no damage when it was picked up.

My Semroc CENTURION flew to an estimated 325' with an Estes B6-4 engine.

Even though it has a baffle, I still play it safe with one square of crepe paper wadding below the parachute. In the inset picture you can see a little charring even after the baffle.
Both 12" parachutes were used.

The "Wasted Engine of the Day" award goes to an A10-3t engine in the Estes BULLPUP. I used an 18mm casing as an adapter.
With all that clay weight in the nose, it probably got 100' in the air.

This was one of the first models built after getting back into the hobby and it's first flight! I was disappointed with the finish (and those stick on decals) so it went to the back of the shelf.
If it flys again, it'll be with B engines and above.

Say goodybye to my little friend!

I rarely lose rockets, my carded BIG BERTHA was gone with an A3-4t engine. I would have to estimate the altitude at about 700' feet.

While the boost was vertical, the winds took it into the houses at the south side of the field. I hadn't flown anything this high today and even with a streamer it was gone.

Oh well, print and build another.

Also flown:
My carded downscale CLOUD HOPPER with a MicroMaxx engine. It took three tries and adjustments to the igniter to get it in the air.

Batter Up Build Part 7 Fin Skins

Here's how the baseball cards will fit over the 1/16" balsa.
Notice the square fold over the leading edge of the balsa.

The root edge tabs are the gluing surfaces to the bat handle.

The interior balsa was cut a little large and will be trimmed off after the skin is glued and dried.
The balsa was set on the glue and burnished.

The card stock was folded over the leading edge and burnished on the other side.

Be sure the root edge of the balsa lines up with the tab folds.
The fins were left to dry overnight in the pages of a heavy book.

Tuesday, October 25, 2011

Cleaning Up Post Launch Part 2

Take the kinks out of your controller lead wires by folding a paper towel, pinch it over the wire and pull the wire through.
Don't pull the wire near the controller body, you don't want to pull on the inside connections.

Here's the wires after taking out the kinks and loosely coiling them.
Don't bend the wire where it comes out of the controller, keep it loose and strain free.

Lastly, wipe down the launch rod with a drop of oil on a paper towel. You could also use some silicone spray.

You'll notice that all this work was done over a sink.
That black engine residue can get everywhere.
Keep it where you can do a quick cleanup.

Batter Up Build Part 6 Fin Design

I thought I'd have some fun with the fins.
A piece of paper was set next to the bat handle to get an idea of a workable size.

The Estes Pop Fly had clear plastic fins.
On a themed rocket like this, I wanted themed fins.

After looking online, I found some baseball cards.
They were set side by side with a little folding space down the middle.
I was conscious of how they would face after folding. I didn't want them to be read upside down.

These cards will sandwich over 1/16" balsa. The leading edge of the fin will be the fold between two cards.
The cards were printed onto 110 lb. card stock.

Monday, October 24, 2011

Cleaning Up - Post Launch Part 1

I try to keep my launcher and controller clean, but it does require some maintenance after a launch.

At the launch site, I'll wipe all the black residue off the blast deflector with a paper towel.
When I get home I'll clean it up a bit more.

This is a cheap, soft brass bristle brush. You can buy them for less than a dollar at home supply and hardware stores. It resembles a wood handled toothbrush and the brass bristles bend if pressed with a finger.

Dampen the bristles (not the deflector) and brush off the remaining blast residue.
TIP: To prevent rust, wipe down the blast deflector with a drop of light oil on a paper towel.

Here's that same brass brush used dry to clean off the micro clips. It this is done regularly, they'll stay in almost new condition.
Using the brush instead of sandpaper, most of the residue will come off pretty easily. Too rough a grade of sandpaper will sand down the clips.

Batter Up Build Part 5 Locking Rings

I cut a 1/4" length of ST-7. This was glued over the back end of the extended BT-20.
This locked the tube onto the handle of the bat.

An engine block was pushed into place with an engine casing.
The engine will extend 1/4" out the back, beyond the ring just glued in place. There is no engine lock clip, a single external wrap of masking tape will hold the engine in place.

Another ST-7 ring was glued over the 1/8" of BT-20 sticking out the top end of the bat. This locked the internal tube in place at the top.

While the Estes kit ejected just the ball at apogee, I used a streamer tied to a length of Kevlar.

Sunday, October 23, 2011

Batter Up Build Part 4 Nose Cone Shoulder

I found a plastic nose cone shoulder from a Starlight nose cone.

It's base was traced around the ball with that fine point Sharpie.
Like on the bat body, the hole was widened with a sharp knife.

I had to use epoxy to glue the shoulder in.

The interior BT-20 was cut to extend 1/8" out the top and 1/4" beyond the bottom of the bat.

Here's the fit of the ball at the top.

Batter Up Build Part 3 Kevlar and a Coupler

With the bat body being over 18", I had to couple two lengths of BT-20 to reach from bottom to top.

I only had a ST-7 coupler in my spare parts box. The ST-7 tubes are a little wider than an Estes BT-20.
It was split and the edges sanded down on my sanding block with some 220 grit.

It was sanded until I got a tight friction fit in the BT-20.

This type of coupling makes a convenient place to lock the Kevlar.
A knot was tied and the Kevlar was looped under the lower end of the coupler.

Before gluing together the two pieces of BT-20, you can see where the Kevlar lies.

This was a scrap piece of braided Kevlar, it would lay flatter than most other stiffer Kevlar pieces.

Saturday, October 22, 2011

Batter Up Build Part 2 Drill and Interior Tube

A BT-20 was centered over the end and traced around with a fine point Sharpie pen.

Using a new blade, the interior of the BT-20 diameter circle was removed.

If this circular cut fits the tube well, it should give enough support. There is no way to insert any centering rings inside the body of the bat.

The finger indents actually hug the Bt-20 very well. It made a good friction fit inside the bat handle end.

The front end of the bat was marked and a circle cut like the rear end.