Twin Boom A/P Slow Stick "Dragon" pusher build thread. - RC Groups
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Jun 18, 2005, 09:42 PM
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Twin Boom A/P Slow Stick "Dragon" pusher build thread.


Well, I have a number of inquiries and so I will take the time to post this.

I will try to compile the basics of my twin boom Slow Stick pusher project. I did not take photos all the way along and I've had to dig for these photos so I will try to explain where i fail in photos.

First - materials:

2 - SS glider kits
1 - extra SS fuse/boom
2 - extra SS plastic parts kits.

Of course all your eletronics, motor etc.

Step One: Center wing panel.

Take one wing and lay it flat out on the table. Take a straight edge and cut the trailing edge off, just up to get rid of the "bat flaps" and make the whole wing nice and straight from one end to the other.

Next, to get about a 6' overall wing size cut one "bay" and the tip off of each side. This will make the center section aproxx 33" long.

Scuff sand the center between the two wing halfs, mist with water and use expanding polyeurethane "Gorilla" glue to glue the center of the wings in the proper dehedral - I used the stock dihedral. Tape firmly over the glued area unless you want to have to sand the glue after if expands. I blocked up one side and weighted the center just to be sure things did not move.

When you get done you should have something that looks like this:
Last edited by CactusJackSlade; Jun 19, 2005 at 02:42 AM.
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Jun 18, 2005, 09:47 PM
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Center panel cont'd


Next is to get your CF tubing out.

I used:

R-08C Solid Carbon Rod .140" Dia. x 48" $7.00
TUP-08 Carbon Tube .230" OD x .144" ID x 48" $7.50

You can get it at http://www.acp-composites.com/acp-cat.htm

Go to the hardware store and get some good fitting aluminum or brass dihedral bracing tubes.

Make your dehedral tubes, cut your CF tubes to length (to the end of the wing panel) and glue into the dehedral braces.

Next, VERY IMPORTANT: WRAP THE TUBING WITH KEVLAR THREAD or it will SPLIT under stress!

You should have something like this:
Last edited by CactusJackSlade; Jun 19, 2005 at 01:08 AM.
Jun 18, 2005, 09:51 PM
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Center panel cont'd


Now that you have front and rear matching CF wing "spars" tape them in place. I used small patches of that criss cross heavy duty strapping tape - awesome stuff!

Oh, I used FOAM SAFE CA glue (the thick stuff) to finish securing the spar to the wing.
Last edited by CactusJackSlade; Jun 18, 2005 at 10:09 PM.
Jun 18, 2005, 09:54 PM
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Center panel cont'd


I finish off the taping, including the center area with red packing tape - like you use on your Zagi/foamie wings.

The center panel is now finished.
Jun 18, 2005, 10:07 PM
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Outer Wing Panels


Next I did the outer wing panels.

This is wher you can learn/avoid the MISTAKE I made when I did mine, so pay close attention!

First cut the center out of the second kit's wing, right at the top of the first "rib".

Now you are going to cut the "bat wings" off again, but you need to make this panel about 1/8" WIDER than the center section since this panel will use RODS that slide into the tubes of the center section... I forgot to add the wall thickness of the two tubes on the center section - about 1/8".

The best thing to do is insert the rods into the center section, measure the distance between them and THEN cut the "bat wings" off the panels.

After cutting off the bat wings I trimmed up the wing tip, I will later taper the trailing edge after the rods are in place.

The CF rods were cut 22" for the leading edge and 16" for the trailing edge. 4" of the rods will slide into the center panel CF tubes.

Same drill here, tape the rods onto the wing with straping tape. I also CA glued the rods on with FOAM SAFE CA glue and kicker. I then covered the rods and strapping tape with colored packing tape.

Here is the right wing panel finished.
Last edited by CactusJackSlade; Jun 19, 2005 at 02:42 AM.
Jun 18, 2005, 10:11 PM
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Finished wing panel


Here is the finished wing panel, just a tad under 6 feet in length.
Jun 18, 2005, 10:27 PM
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RUDDERVATORS - stab - A tail


The "A" tail was next.

I again cut the bat wings off the tail. I then went to one side and just where the radius of the curve started I cut it off square. This makes it about 14.5" from one tip of the stabilizer to the cut. Cut the movable surfaces "ruddervators" to match.

Next I joined the Stabs... but I wanted them foldable/detachable from one-another. I used 2 plastic aeileron hinges for this. I cut the end of the hinge pins off, slide the pins out and replace the hinge pins with one long "L" rod.

The hinges will be glued to each stab and the L-rod will secure them together, yet allow them to be separated for trasport.

Bevel the underside of the stabs 45 degrees on the bottom side trailing edge. Install the ruddervators on using whatever hinge method you like, i just tape them, but I use the "opposing" tape hinge method along with one across the full length of the top side.

Here is a photo of the hinges ready for insertion/gluing into the stabs and also the finished assemble with the ruddervators tape hinged on.

Here is that taping method I like as well.
Jun 18, 2005, 10:39 PM
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Twin Booms


The deciding factors on the distance between the booms was the size of prop I wanted to swing and also the angle of the "A" tail desired.

I came up with 16" center to center on the booms. This gave me the ability to swing a 12" prop (with room for the push rods along side the booms) and gave me an acceptable "A" tail angle (about 100 degrees). I wanted this narrower than usual A tail angle for more rudder authority and less elevator authority.

Next I glued on 45 degree balsa strips on the ends of the booms. They are the same length as the chord of the stab. I glued them on "over lapped" so I had extra material to sand to the 100 degree angle.
Jun 18, 2005, 10:43 PM
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Attach A tail


I slid the plastic wing mounts onto the booms and rubber banded center section of the wing on.

I squared everything up, scuff sanded the bottom contact patch area of the A tail and epoxied the A tail on.
Jun 18, 2005, 10:44 PM
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Landing Gear


I next concentrated on the Landing Gear.

The front gear I "doubled up" by cutting the "axle" off of one side, bending the leg until it contacted the other side and then kevlar wrapping and CA gluing the two legs together. It works very nicely! Note the small screw through the forward plastic wing/gear piece - keeps the gear in place and the plastic part from sliding.

For the rear gear I went from scratch. I used .054 piano wire and again doubled up the legs by bending half, installing the foam wheel and bending the other half. It installs just like the stock rear gear.

Photos should say it all.
Last edited by CactusJackSlade; Jun 19, 2005 at 01:57 AM.
Jun 19, 2005, 02:11 AM
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Now that the plane has legs...


I then slid on all the plastic parts needed on the two booms for a final fit.

In order:

Servo push rod guide
Rear wing mount
rear servo tray mount
Front servo tray mount
Front wing mount

I then mounted one servo on each boom toward the inside. I made CF pushrods to replace the whimpy stock ones.

Rubber band the two booms and A tail onto the center wing section.

Install control horns, conect push rods.

************************************************** **
Although you will have to experiment with the center boom arrangement, this is what worked for me:

Install onto center boom in order:

Rear wing mount
Two "battery holders" (sideways) to hold Rx
Front wing mount
4 battery holders

Rubberband the center boom onto the center of the wing.

INSTALL:
Rx, speed controller, servo extension wires, motor/GB etc.

This is a photo of the belly of the Depron Dragon, which has the same layout:
Jun 19, 2005, 02:15 AM
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Motor Mount


As I mentioned in this thread here: https://www.rcgroups.com/forums/showthread.php?t=384182

by adding a motor mount riser you can cure the ground clearence/prop problem and minimize the throttle nose-up tendency... both in one mod.
Jun 19, 2005, 02:21 AM
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CG and test fly...


For a test flight I use a big and heavy 8 cell NiCad battery pack (from my Zagi days! ) to strap onto the nose to simulate some of the future hardware.

I balanced the CG at about the same point as advised for the stock SS with good results... maybe a hair forward. YOU DO NOT WANT IT TO BE TAIL HEAVY on the first flight.

Very well put by someone with better wits than I:

"A nose heavy plane flys poorly, a tail heavy plane flys once!"

Check you V tail mixing, set up your throws, re-check CG, do a range check... and GO!

Hope this helps!

CJS
Jun 19, 2005, 02:24 AM
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MUCHAS GRACIAS MY MAN!!

Thank you for the repeat walkthrough on your design. LOTS of great stuff!!

You Rock!!

Qualcity
Jun 19, 2005, 02:40 AM
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IMPORTANT MODS before you load it up...


BEFORE you go and add your 16-24 ounces of payload it is important that you beef a few things accordingly.

The main two items are the front landing gear and the wings... which can all be beefed up with an EZ removable Kevlar thread arrangement.

Here is a diagram, when I can I will add photos.

I use fishing snap swivels where I want the kevlar thread to be detachable, like on the wings and the center boom - it is wrapped and CA glued the the landing gear.

CJS
Last edited by CactusJackSlade; Feb 14, 2006 at 12:12 AM.


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