That a really nice looking model, looking forward to following the build

  Larry , most people won't be able to find a Cox killer Bee , if you had to buy a motor today it would be the Cox Int. product motor , Brodak 1/2A or the AP Wasp .061.
    Bill

 Larry , I have two of the original Killer Bees  left after trading a third one on a mouse racer for a Super Pow Wow . The Killer Bee was extremely competitive in the few mouse racers  I entered as a pilot [the pilot wasn't as good as the motor ] .
   My point was maybe Larry should use a standard Cox product motor . But if Cox Int. is planning to make a true killer Bee again then it makes sense . Like you said "one can only hope" .
    Also I am proposing to the Valley Circle Burners next meeting to do a 1cc Stunt for Cash contest at the Sepulveda Basin in late June . No trophies just cash ! Will do an update after the meeting Jan.16th 2010 .
   Bill Barber

I am taking a nice trainer and conveting it to a killer competition machine.  As Captain Kirk would tell Scotty "I need POWER NOW".  There is no substitute.  Trainers fly on 26' to 35' lines of dacron.  I need to fly on 40+ ft of .008 steel and get good line tension overhead.  Stay posted for my progress.

The 4 gospels of stunt are "Size, Shape, Intersections and Bottoms".  If you ain't got them all, you ain't going to stunt heaven.

That said, the thread becomes increasingly more interesting!

Did you do anything extra to the nose area for reenforcement? I thought I was seeing something extra on the triangle stock behind the firewall.

Robert

Here is the model ready for final installation of the hardware.   Finish is 3 coats of butyrate dope (sanded between each coat with 600 grit), add the decals, and then two light coats of LusterKote clear gloss.  Man, that is at least a 5 point finish! (out of 20 possible)  But it is very light, and very fuelproof.  Perfect for what I need.  I can't imagine that even the large decals add detectable weight.  I still hope for around 5 ounces finished.  Less would be nice!

The line is spaced about 1/16" apart and 3/16" from the hinge line.  There is plenty of meat there to hold the elevator on, and the threads themselves have a huge margin of overstrength.  The number of loops is based on the balsa strength, not the thread.  I suspect two loops would suffice, but 4 in several locations doesn't cause any binding, so why not.

Figure eitht hinges have been outlined elsewhere, so do a search.  Basically, you run a needle and thread through one surface, pull it to near the end, glue the end.  Then up through the hinge joint and down through the other surface, up through the joint and down through the original surface.  Viewed from the side it forms a figure eight of threads.  When you have 3 or 4 eights, tighten up the thread, level the two surfaces and glue all the penetration points top and bottom, but not the thread where it goes between the surfaces.

Definitely my favorite hinge for 1/2A.

Here is a close-up of a hinge.

What is "spiderwire" and where does one get it?

Spiderwire is a fishing line made of Spectra thread.  It is incredibly strong for its size and weight, and unlike Kevlar, is not prone to fraying from flexing and abrasion.  Unfortunately, Spiderwire has expanded its line to include monofilament nylon.  It is worthless for our purposes.  Be sure to get the woven or braided (multifilament) line only.

The stuff is good enough to use for flying lines!

Never try to cut it with scissors, it just won't.  You have to use a very sharp knife on a giving surface like wood or hard plastic.  Knots will slip unless you use a special one like the "Palomar Knot".  I just tie a square knot and fuse it with CA Glue.

The "Ultimate Handles" from RSM use Spiderwire for the leads.  Never had a failure.

Some kite line is also made of Spectra.  I have a local kite shop in North Alabama that keeps bulk spools in many pull tests.  He will sell it by the ft. His contact info is:

Forever Flying, L.L.C.
2528 Spring Ave, SW
Decatur, AL 35601-6345
Phone: (256) 308-0988
Fax: (256) 308-0658
Email: info@foreverflying.com
http://www.foreverflying.com/

Although not legal for AMA events I have used it for flying lines etc:  Good stuff!!

It comes in a variety of tensile strength levels.  For a Ringmaster, I would want at least 50 lb test, as the strength at the knots is compromised a bit.  I am not aware of anyone doing standard line ends with the stuff, but that could help a lot.  Be sure to bevel the inside ends of the tubing you use!!  I would make up a short sample and then pull test it to destruction.  For a .35 powered Ringmaster, I would want the test sample to hold at least 40 lb .  That gives you some margin for "oops".  In my experience, wire will stretch on impact, but Spiderwire will break.

About 1/2 way down the page is some kite line. It comes with a line winder and sleeving for the ends.  The sleeving eliminates the breaking at the knot problem. Not legal for AMA events but will work.  It is the same material as Spider Wire only it has been polished to make it slide over each other.

http://www.foreverflying.com/access.html
 
75lb/75ft (Berry Blue-Line Spectra 2000 w/winder and straps) - $27.95

Obviously I have a bunch of the stuff at my house because I fly two string stunt kites.  I have not tried kite string on say my Ringmaster however I have flown 1/2 A on some of the lighter stuff.  The only reason I would be temped to try it on a bigger plane is the fact it is bullet proof.  If some jerk steps on your lines on a grassy field they would not be damaged. I have had kids stomp all over my kite lines at the beach with no problem. By the way my 7' kite pulls like a bear. It will drag your feet in the sand on a windy day.  If set up properly their is no breakage problem. Also they are easy to wind up.  Having said all that I probably never will get around to trying it on a .35 size ship.  As the old saying goes if it ain't broke don't fix it.  For me steel lines work just fine.

       

So what size Spiderwire do you use for 1/2 A - .061 flying lines? Is spiderwire the only workable brand? there is also PowerPro, made of spectra, and probably many others today. The PowerPro 8 lb test is 0.005 dia.

W

I am not familiar with fishing line but I would think any line that was made of Spectra and is braided (vs monafiliment) has to work.  The beauty of the Spectra family of string is that it has almost no stretch.  I have found that new Spectra lines need to be set by stretching.  After I make up a set of lines I hook one end to a nail on the garage door jam.  With the controll handle attached to the other end I give a big pull.  Obviously you need to stop short of breaking the line but I can feel the line give a little till it "bottoms out".  At this point the line becomes as stiff as wire. A better methoid would be to use a pull test scale but I dont have one. Good stuff for 1/2 A lines.

 

I use the smallest stuff I can find, it is still overkill!

I've had the conversation about Spiderwire with a few and never get a "Specific" answer on what flavor is used. I have some that I bought that I am sure is the wrong stuff as it breaks very easily.

Box Color
Model Name
Test

Any of the sources for the stuff carry different "models" of the stuff. (Referring to "Spiderwire" as the Make.. if you will to make this more clear)

Mark

Pardon my interuption of all this talk about spiderwire and sewing hinges onto models to ask a question about the subject of this topic.
Larry, how did the plane fly?

Larry

Bill,
     Aside from Larry's special needs I would like to point out that this model was designed for the Cox Sure Start engine with the choke tube in place and that Larry has modified it to fit the Killer Bee. Cox is looking into making these type of engines available latter this year. We can only hope.
The other Larry

Hi Larry,

Back to your kit and the mission at hand.

As far as this modication goes. Sure Start or Killer Bee both have the exact same mounting pattern. These Horseshoe shaped firewalls are the same for both engines with the exceptions of the snorkel. When I have ran the SStarts I pull the screws and remove the snorkel. Then it exactly the same. I also shorten up the needle Valve.  What I am saying here is that it should have worked "Stock" and the modification probably had more to do with the removal of the "extra material" below the engine in the stock configuration for the weight savings and appearance sake.

It is a neat looking plane and I think its great that its set up to run with the Snorkel on. This should have been done a very long time ago. If I were a young person I would like to see the photos that you take of the Captain Blackhawk "Here is what your buying"  model with the "Tank on including the fuel line"  Its not that we cant figure it out but I can tell you that everyone will refer back to the box when building one of these.

Larry Rengor,  Get better and we all look forward to the results. I have engines ready to hang on a copy after you make it work.

Mark

Mark,

     There are several reasons that we do not show the fuel tank on the box art or in pictures. I do not want to be the person who tells you which fuel tank to use or not to use. Any fuel tank of appropreate size may be used, square, round, rectangle, wedge or balloon may be used and as to the location and fuel line placement ...
     Okay here is a question for all of you: On a profile model where would you place a fuel tank other than on the right side of the fuselage with the fuel feed lined up to the engine air intake. Now I do not mean to belittle anyone or anger anyone I just do not know and I have been asked by old time experanced modelers where the fuel tank goes, so if you have somewhere else to put it please let me know. Type of tank for stunt should be a wedge tank but any other will work. Fuel line should run in any direction as long as it is as short as posibable and does not kink.
     We do not show controls and fuel tanks on box art, and this is true of most companies, because it makes the model less attractive, these items are saved for on the plans.
Thank You for the question and please do not be offended as I know that you are only trying to help.
Larry

"Okay here is a question for all of you: On a profile model where would you place a fuel tank other than on the right side of the fuselage with the fuel feed lined up to the engine air intake."

Larry, I think most of us grew up and were told that the tank should go to the outside of the circle, or the right side like the bigger ships.

In the past few days I have come to disagree to this for some Cox engines.
I say this because of what I learned earlier in life that the tank pick up tube should be in line with the spray bar. This is true.
These days when using an engine where that spray bar location is pretty much centered on the firewall, locating the tank on the inboard or left side of the fuselage would be the most logical place for the tank. 
This should hold true with other reedies and even front rotor engine types when radially mounted with the cylinder up, down or to the left.

Rotary intake engines with the cylinder mounted to the right or outside of the flying circle would need the tank on the right side.

Robert   

Okay, robert, I don't see it. Maybe I am dense here but with the intake centered on the firewall it should not matter where the cylinder is pointing. On the inside of the circle you would only gain a fraction of an inch of shortening the fuel feed distance. What am I missing.
Larry

Larry, you hit the nail on the head! You do understand! The point is that you would GAIN that fraction of an inch of shortening the fuel line feed distance as opposed to making that distance a fraction of an inch longer!
Any gain to the good is good I always say.

Robert                                                                                             

This is a good conversation on the fuel tank position.

Many of us are playing with these little engines that these particular planes are designed for.  

A good example for me is that I have fuel delivery issues with My PT-19s that have the backplate motor. The regular ole Babe Bee never had an issue. The quote is: "It just works." I am talking regular flight with a wingover here and there. Althought the regular flight has been very inconsistant. Fuel Line placement as well as the tank design I am fairly certain are the issue. I am interested in building some of these BlackHawk planes designed specifically for this version of the engine. I will be interested to see what Mr Renger makes work.  (fixed the spelling on Larrys lastname)

Robert, Thanks for those additions..

Larry, This will be good for your product and good for Cox International. A good recipe for success makes a Sure Start plane an automatic "Boy/Cub Scout" project. I have a nephew in mind for this already.

Mark

Keep in mind that my idea is neither original nor unique it seems. Check out the drawing that was on the back of their package for the Goldberg motor mount adaptor for Cox engines.
Also keep in mind that Goldberg did not infer nor imply that this tank location was better in any way or for any reason.

Robert

OK the Bullet got into the air and shows potential.  Unfortunately, the Holland Hornet on the front needs a new needle assembly.  This will happen this week sometime.  The plane seemed to fly smoothly with good maneuvering potential.  The weight came out 4.85 ounces!  Fuel tank is an APS film cannister set up as a uniflo system.  Prop, currently is an old plastic Zinger 6x2.5 .  Lines are 45 ft of .008.

If you wanted a current combo that is equivalent, I would go with the Brodak .061 and modify the head to use Merlin plugs, or the AP Wasp with Jan venturi.  They would actually be overkill on this small and light a model, so you would have to use really low nitro and a 2" pitch prop and probably longer lines.

Anyway, here are some photos of the finished plane.

Upon looking at the photos I realize that I need to raise the engine, or set it up with the cylinder horizontal to get the spraybar in line with the tank centerline.  Good thing I didn't go inverted today, the engine would have died lean, for sure!!  Saved by a defective needle, how nice!! 

Antone Kephart, Stan Tyler and I all flew it over the weekend.  I think they are still grinning.  A sheetwood airplane can't DO that!!!  We all flew every pattern maneuver, no problemo.

Antone is thinking of doing a sheetwood baby Magician to the same dimensions as the one I published in Flying Models an aeon ago.  He wants to kick ... in open Profile with it and shock and awe the troops. 

Still a bit of difference up and inverted, so I pulled the tank off, replumbed it to lay on its side rather than more vertical.  Not exactly in line, but much closer, and the shape of the tank should help limit fuel sloshing at the end of the run.  I might put some of the plastic brillo pad stuff in the tank to dampen sloshing even more.  Nice to be able to just pop the top off the tank and make adjustments!

SAVE THOSE APS film cannisters.  Harvest them wherever you can, they are obsolete!!!

It seems to be a Norvel insert.  I guess the previous owner drilled out a dead glowhead to use as a retainer. (Unless someone makes an adapter?)  Whatever it is, starts easily and runs well.