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Old Jan 22, 2013, 09:03 AM
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juanjulian's Avatar
Guatemala, Guate
Joined Jul 2007
276 Posts
My godies from hk arrived the second week of january. So now I have retracts and edf motor. My servos arrived from a usa vendor heads up rc.

Not using top of the line gear for this build but think the gear selected has good reviews.

My tail fin got fixed by strapping it to one side with masking tape and heatin it up with a heat gun. It was a easy fix took more time thinking about it than doing it. Also finished the fin by putting the hinge points that came from hk. The servo will go inside the fin with a opening for the horn.

One of the retracts does not comes back by itself. Opened it and has some scratches in the inside. Think that with the weight of wheel will be enough to start it going. Not a big fan of hk but for accesories nobody can beat them.

Tower pro servos
Changesum fan with lm2855 2800kv motor

Retracts

Fin


Cheers

Juan
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Old Jan 22, 2013, 09:49 AM
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United States, CA, Chino Hills
Joined Mar 2007
376 Posts
Ka l39

I have one of these NIB but have not built it. Looks like a good quality kit. For the price the should be. Well I'll keep watching. If anybody needs one to build along here give me a pm.

Well Looking great so far. I think I have some of these micro gear to....
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Old Jan 22, 2013, 12:00 PM
turbonut's Avatar
upland CA
Joined Dec 2004
7,199 Posts
looks like your gettin there..it wont be a rocket with the CS fan but will fly very well..I also have the same kit..well I think three of them..Time to finnish one up..FYI with about 1400 watts in a wemo fan this will do over 140mph
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Old Jan 24, 2013, 01:42 PM
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juanjulian's Avatar
Guatemala, Guate
Joined Jul 2007
276 Posts
Finished the instalation of rudder servo and linkage.

Since the fuse is open is really easy to install the servo this way. On a Savex l-39 that build for a friend was a pain installing the servo in the ruder with internal linkage. This form it is easier to adjust. The glue that used to glue the servo in place was goop.

Turbonut will apreciate some detail info on building the flying stabilizer, specially the pivot point measurement from leading edge. Think why invent something if it has been done.

Cheers
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Old Jan 24, 2013, 05:24 PM
Just having fun before I die!
BadLemon's Avatar
DeKalb,IL
Joined Dec 2008
922 Posts
Hi Juan
Glad your rudder repair worked out it's a scary moment when you first start to apply heat you think it's just going to melt into a ball of fiberglass at any moment! Also have you used those tower pro servos from Heads up Rc before? How do you like them!
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Old Jan 25, 2013, 06:43 AM
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juanjulian's Avatar
Guatemala, Guate
Joined Jul 2007
276 Posts
Doug
This will my first time using tower pro servos. Got the 9 gram metal gear for ailerons and a carbon resingear for the other surfaces. They seem to have good reviews and use them a lot in the trex 45o clone. They have 22-27 oz being the metal gear the highest.

Tried all of them and seem to center well.

Cheers

Juan
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Old Jan 25, 2013, 08:01 AM
Just having fun before I die!
BadLemon's Avatar
DeKalb,IL
Joined Dec 2008
922 Posts
Juan

Thanks for the info, one thing you mite what to consider is using a metal gear servo on the Elevator. most of the time more force is generated on the servo pitching the aircraft then rolling it.

Food F Thought.

Doug
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Old Feb 02, 2013, 10:06 AM
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Guatemala, Guate
Joined Jul 2007
276 Posts
Days before worked a little on the servo bay of one wing. Messed the first one since servo was protuding wing and had to move servo to center of wing. Did not notice on time tha the plastic cover that comes with kit was the tip of were in wing the servo is located. Have no plans only a written instruction and a diagram of plane of location of components with no specific measurements. Not a big deal if you have some build experience.

This friday night advanced on the other wing servo bay and started the retract instalation in one half wing. Was hoping in getting some detail instruction with measurements but could not get anny so had to use my ingenuity.

Located cg on wing half and traced a horizontal lonemin wing. Moved back this line half an inch to place location of wheel. Bended a dummy wire to get an idea of weremshould retract go.


Opened a channel in the wing. Used a hot wire to cut into the foam. A new chanel has to be made in the foam to allow a passage of the air tube to retract. The servo channel needs to be modified since the wheel will obstruct the original channel. It is scary removing big parts of foam, thinking the wing will be ruined. The new wing is hallow molded so should not be a problem.





Build two plywwood spars gluing two 1/8 inch plywood by 1/4. This spars extend to the center of wing, and the idea is that the spars will serve for two poposes, retract placement, and wing spars. Never liked the idea of just gluing a block o wood to hold retracts in place. This spars distributes the impact forces in a wider area. To help in the torsion will add a wing fence that also will be glued into the spars.


Could not worked more since epoxy had to cure and already was into the morning. Will cover with balsa the retract channel leaving open only the retract area, and cut to shape wheel bay.

Cheers

Juan
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Old Feb 03, 2013, 11:17 PM
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Guatemala, Guate
Joined Jul 2007
276 Posts
Worked more this sunday finished the next half wing.


Glued wing together.
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Old Feb 03, 2013, 11:50 PM
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upland CA
Joined Dec 2004
7,199 Posts
It looks like you are moving along well..sorry no pics I have been working 7days a week for a while now...
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Old Feb 04, 2013, 07:49 AM
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Guatemala, Guate
Joined Jul 2007
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This morning the wings glued well. Just added a little more epoxy to the bottom seam were it did not reached. Ready for some filler and final sanding for a glassing job.



Thanks turbonut. If you can only give me the measurment of pivot point for elevator will apreciate a lot.

Cheers

Juan
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Old Feb 06, 2013, 07:50 AM
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Guatemala, Guate
Joined Jul 2007
276 Posts
Played last night with torch and bending landing gear.

Will share this really usefull article found in the internet.
///////////////////////////////////////
By:Roy Vaillancourt
The music wire that we use for landing gear and cabane struts is medium carbon steel that has been heat-treated to a spring temper. It is generally very useful to us in this form.
Spring temper defines a metal hardness that, if measured on the Rockwell hardness scale, would be about Rc 45. At this temper steel is referred to as being in the “tough” hardness range, with a Rc 20 being considered soft and Rc 60 being considered hard.
When in the tough temper state wire can be worked, but not as easily as if it were soft. In this tough condition it can be bent and cut using the proper tools and techniques, however, sometimes this tough state is just too tough for us....
To work steel more easily we can heat it up, and as it heats it becomes softer. While in this softer state we can bend it the way we need it. After we have bent or formed the wire it may cool at an uncontrolled rate. This cooling rate is directly responsible for the hardness of the wire after it is formed. As a result the finished part may be much softer (or harder) than its previous state. Now for some parts that’s ok... but for landing gear we just can’t leave it in the soft state because on the very first landing the wire would simply bend and not “spring back” to its original position or shape. If we left it in a hard state the next landing would snap the wire. So, to return the steel to its springy condition we must restore that specific spring temper by heat treating the appropriate area.
The steps that should be taken in order to form wire more easily would be to first anneal it (that is to soften it), form or bend to desired shape and then re-heat treat the part back to the spring condition. First the wire should be annealed at the location to be bent. To anneal heat your wire with a torch until it becomes a bright cherry red (this color represents about 1400 degrees F). Let the wire cool completely to the touch. Don’t quench it or blow air on it. Just let it cool naturally away from any drafts. The wire should now be in the Rc 25 range. This is considered soft and you will find the wire bends very easily at this hardness. After forming, once again heat your wire with a torch until it becomes the bright cherry red but this time “quench” (rapidly cool) in room temperature water. When plunging the steel into water, do it with a twisting swirling motion to prevent water vapor from insulating the wire from the coolant action of the water. This will insure that a more even quench is therefore obtained.
At this point the wire should be very hard... probably above Rc 60. To test whether this is so attempt to file a mark on the super-hard area. The file should slide off without cutting into the steel at all. If, however, it does not slide off but cuts, you did not heat and quench properly or you do not have high carbon steel... Try the heat and quench cycle again. If your file still cuts then you definitely don’t have high carbon steel.... So get another piece of wire and start over because you will not be able to add the necessary carbon to low-carbon steel. If you are successful in getting it very hard do not try to use the wire while it is in this very hard state. It is quite brittle and will snap off.
The next step is to temper the wire back to the desired hardness. Tempering is a form of annealing but is controlled so that the steel “stops” at a specific hardness. Start by shinning the wire with steel wool or emery cloth. Then heat it up gradually using the torch and watching for the following colors as a guide: The first color will be straw (350 degrees), followed by a dark blue (600 degrees), which is followed by a medium blue (750 degrees). At this point remove the wire from the heat source and allow it to cool slowly. DO NOT QUENCH IT OR BLOW ON IT! Just let it stand to cool on its own at room temperature away from any drafts. Once the steel returns to room temperature it should be at the target RC 45 hardness, which is a good spring temper. Perform the file test again. You should be able to make a mark now.... But with some effort. If it passes this test you have tempered your wire to the proper degree. Good luck!
Tempered music wire can also make great special purpose tools. Instead of tempering to the 750 degrees, stop at the straw color stage and you’ll have the wire at about Rc 60; it is still very hard, but not so brittle. Wire at this temper makes great drills for wood and plastics and most Aluminum and Copper.
/////////////////////////////////////////////////////

So tried bending my first spring for the front strut. The first one snap breaked after templing it and fooling with it. It was so brittle that with litle effort braaked.

The second one came ok and this time heat treat it imediatly after templing. The wire used is ks saller size than1/8 inch.

A brass tube was soldered to the struts since retracts are 3mm. They had to be sanded to size.


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Old Feb 09, 2013, 06:46 PM
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Guatemala, Guate
Joined Jul 2007
276 Posts
Putting the retracts was not as easy at it seemed. Messed the struts by cutting more than necesary so had to build new ones. The retracts were to into the wing so had to sheem the retracts so they can lock when wheels go into. The plywood spar tha is into the wheel hole was to thick so had to dremel off so wheel will fit.



Started the elevator and will be flying stab. Found a picture in the clasifieds of hinge poin in elevator so used 36% of mac.
http://www.rcgroups.com/forums/attac...mentid=5460880

Build bushing for elevator

Glued bushing to fuselage
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Old Feb 15, 2013, 08:41 AM
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Guatemala, Guate
Joined Jul 2007
276 Posts
Have done more work for elevator.


Made elevator horn using dubro hd arm and gluing a wheel collar this works really good.




Elevator fited in fuselage.



Pending sanding to shape elevator.
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Old Feb 15, 2013, 11:27 AM
turbonut's Avatar
upland CA
Joined Dec 2004
7,199 Posts
Nice work..you did your tail almost exactly the way I did mine!
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