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-   -   Kangaroo-NitroPlanes-Assembly (https://www.rcuniverse.com/forum/arf-rtf-75/6732742-kangaroo-nitroplanes-assembly.html)

Crazy4Flight 12-09-2007 12:24 AM

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On Black Friday Nitro Planes had a sale. I bought the KANGAROO. It looks like a clone of the Balsa USA's Force One. A pusher prop deltawing. Colors are silver, black and orange. The ad said the Kangaroo was retract ready. But no listing in the retracts for the Kangaroo. An Email about retracts to Nitroplanes has gone unanswered to date. OK, I have a set of Spring Air #305 lets use them.

Main gear pockets in the wings were very close to size I only had to lengthen the pocket by 1/8". OK proceed lets do retract instead of fixed gear. Cutting the soft sheeting was no problem and not much glue holding the wing sheeting down to the landing gear blocks. On one wing you can see the ribs are not perpendicular, add some glue and hope it holds.

Next are the wheel wells. One of the vacuum formed wells has a large radius around the well to the flat glue flange. This radii holds the well out of place above the wing instead of sitting down flush. See pictures below. Note that the good well has several little dimples around the flange in the tight radii. Those are from small vacuum holes drill in the mold to assist the drawing down of the plastic over the mold cavity. Nitro Planes will get an email about this.

While working on the gear pocket best to do the servo pockets. They are exposed by removing the covering, the servo mount has a doubler in it to provide 6 mm of wood for the servo mounting screws to pass thru. Also a notch was laser cut to allow the servo lead to pass through without getting hung up. Pilot drill then install and remove #2 screw, and then a drop of thin Cya to harden the threads. The string provided to pull the servo lead the wing was too short. No slack made it useless to me. With retract unit removed I was able to finesse the lead with a dental pic through the ribs and under the wing tube and exiting the wing.

Each wing has an elevator servo pocket for a mini servo like the Hitec HS-81. I will skip the dual elevator servo set up and put a Hitec thin wing servo, HS-125mg, in the stab and route the extension through the wing. Ribs will be doubled up for mounting a servo hatch and the servo will be mounted to it.

The fuse is set up for a flush mount unit like the wing. A little surgery will be done in the nose for steering arm.

Next problem is the 6 mm dowels for the wing-fin-stab alignment at assembly. The wood dowels are less than 5.5 mm in diameter! Too sloppy of a fit here! Note: The fins, are called rudders in the manual, are to be glued to the wings with a portion of the dowel to extend into the stab. Thankfully the aluminum wing tubes fit fine to the wings and fuselage. The whole plane is assembled by sliding the wing onto the tubes up to the fuselage just before they meet the stab is placed on the dowels that pass through the fins.

Power will be an OS .50 SX with a Pitts style muffler.

opjose 12-09-2007 12:02 PM

RE: Kangaroo-NitroPlanes-Assembly
Re: Wheel wells

I posted this in the support forum...


I had the same thing with the Bobcat's.

...Not really a problem.

Enlarge the opening slightly, and when you glue or screw the well into place, push it down and in.

This forces the walls to conform to be a bit steeper.

You can also CAREFULLY hit it with a heat gun and press it into place as you do so.

But you must be VERY careful not to overheat the plastic and the temp variance is fairly small where this occurs.

Kmot 12-09-2007 12:10 PM

RE: Kangaroo-NitroPlanes-Assembly
C4F: I like the "zoomies" headers! :D

Crazy4Flight 12-09-2007 06:10 PM

RE: Kangaroo-NitroPlanes-Assembly
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I cut the Horizontal stab open to install a Hitec HS-125 MG servo. Made a hatch and itis ready for assembly.

The wood dowels supplied are less than 5.5 mm in diameter a SLOPPY fit for 6 mm holes.
A trip to the Orange store got 1/4" dowel to sand down to a good fit a 6mm.

Rudders will be added to the fin panels.
Servos will be place in the original elevator pockets.

I will fly the plane using Elevons mixing, JR sport 125 mg servos supply more torque than needed.
My Futaba 9CA P-mix elevator to an aux channel to drive the real elevator.

Most delta wings need plenty of elevator throw.
With this set up I will hve plenty of control authority.

BadSplice 12-10-2007 11:15 AM

RE: Kangaroo-NitroPlanes-Assembly
I like what you did with the elevator. I had gotten 2 mini servos to use on mine, and was planning on doing the same thing, but with 2 servos, now Im thinking about buying one of those. I will follow your thread with interest. It looks like you are working your way from the back forward, which is perfect, since I started in the front.

Its in the Tips and Techniques forum http://www.rcuniverse.com/forum/m_6701444/tm.htm

Crazy4Flight 12-10-2007 05:55 PM

RE: Kangaroo-NitroPlanes-Assembly

I am working on the "front" I have to lower the nose gear retract mounting rails by 1 1/4". The spring air retract has to be at the lower depth to be "flush" when gear is retracted. Nitro planes had some other rretract in mind I guess. But I had the 305 set on my shelf. Me thinks my Patroit kit is pi$$ed off at me for using its retracts. Checking the Patroit's assembly manual as well as a Cermark F-20 and looking at this retract unit needs mounting surface inside the plane not at skin level.

Last night I took out the origional mounting rails and made a plate to drop in place. Set in with 20 min epoxie. Tonight I will make gussets to hold the plate in place. And then to look for a way to put a screw or two in for added strength. What I did not have interlocking parts.

The OS .50 SX was just set in the engine bay It has not been installed.

BadSplice 12-10-2007 07:03 PM

RE: Kangaroo-NitroPlanes-Assembly
I have a feeling whoever drew those rails into the plans didnt actually understand how retracts work. I have a set of cheap hobbico mechanical ones, and I also had to raise the rails by 1 1/4" if I remember correctly. (might have only been 1 inch, but I added to the bottom of the body there to make room to totally enclose the nose wheel) I looked at it for the longest time, and I couldnt imagine Any type of retract that could possibly fit there and still have some sort of steering Mechanism.

Crazy4Flight 12-10-2007 07:42 PM

RE: Kangaroo-NitroPlanes-Assembly
If they were Robart 630 series then the idea would be right but thos fit ny 18lb jet!

Crazy4Flight 12-10-2007 11:10 PM

RE: Kangaroo-NitroPlanes-Assembly
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Rudders covered and hinged, need to add checkerboard squares.

Elevator hinged ready for servo linkage.

New floor for nose gear 1/4 plywood with a partial doubler in the center for the screws.
Floor is dropped 1 1/4 inches.
Still need to add reinforcing gussets. And set up steering servo.

Crazy4Flight 12-11-2007 09:32 PM

RE: Kangaroo-NitroPlanes-Assembly
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I cut the covering over the elevator servo pocket, which will now be the rudder servo pocket.
First I hade to trim some wing sheeting back to fit the micro servo ( Hitec HS-81).
Next the gusset supporting the servo mount had to be notched to clear the servo lead.
see photos red lines & arrows.


The intened rudder linkage won't work! It will hit the elevator and then would need a 90 degree bend!
I could cut an angle off the elevator and make a J hook linkage like on a four stroke throttle set up, NOT!


Mount the servo on the top of the wing outside of the fin panel.
Requires carefull cutting and proper support under the wing skin.

Crazy4Flight 12-11-2007 09:39 PM

RE: Kangaroo-NitroPlanes-Assembly
ADDED NOTE: the propeller slot is about 11.5" across.

Crazy4Flight 12-15-2007 05:17 PM

RE: Kangaroo-NitroPlanes-Assembly
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rudder servo mounting had to be done on the top of the wing.
pictures will show why it is good to measure vs. eyeball guesstimate
the side of the servo pockei is 1" outside of the fin panel
the rear edge of servo pocket is 5/8" in front of the prop clearance notch in the wing
My first cut started too far forward and was over the retract pocket thius the support block for the servo had to be moved aft. The support bloch front hads a notch to clear the servo lead, it is fitted between the wing skin and gear mount. It is also notched to be flush with wing skin to fill in my rerror. the rear support block measured 1/2 x 3/4 x 1 1/16 the height had to be sanded slightly to fit the curve of the upper wing skin. 15 minute epoxie was used. The servo wire will need and extention to get into the fuse and a Y cable to run both servos. no reverser needed. I had a pair of Futaba S3102 on the shelf and will operate the rudders.

Crazy4Flight 12-15-2007 05:37 PM

RE: Kangaroo-NitroPlanes-Assembly
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Motor mounting:

I used the supplied mount and hardware. The mounting screw holes needed a bit of clearance 11/64 drill was used to open the holes in the mounts. This compensated any error preinstalled blind nuts. My OS.50SX had a snug fit between the rails, I broke the sharp corners with a file to relieve stress and it fits fine. I prefer to use 4-40 screws to mount engine. The mounts will be drill and tapped for 4-40 and nylock nuts will installed to prevent the screws from turning loose from engine vibration.

Instruction manual had some errors. One was an editing problem since the blindnuts were installed. The other said the firewall to prop flange on the motor was 145 mm (5.71"). On my plane 108 mm (4.25) was the correct distance to center the propeller between the fuselage and the stabilizer.

A pitts style muffler will by used. Exaust openings point downwind. The muffler was given to me so I do not know the brand and model #.

Crazy4Flight 12-15-2007 05:45 PM

RE: Kangaroo-NitroPlanes-Assembly
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Nose gear mount: A view looking inside the fuse. Plywood was doubled for mounting screws. And a block of balsa was epoxied above the gear plate and to the front former and sides of the fuse.

Crazy4Flight 12-18-2007 11:05 PM

RE: Kangaroo-NitroPlanes-Assembly
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engine mounted useing supplied mount. OS .50 SX is held in place with 4-40 machine screws and nylock nuts. Throttle linkage was easy with the guide tube has a slight offset bend to line up with throttle arm, and a slight drop to the servo. Engine bay was pre-coated with? (clear dope?) for fuel/oil proofing.

Fuel tank was discarded. Too many arf tank leaks in the past! Tower Hobbies 8 oz tank was used.

Crazy4Flight 12-18-2007 11:26 PM

RE: Kangaroo-NitroPlanes-Assembly
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Elevator wiring. I cut a slot in the left wing near the TE to feed the servo lead through matching the horiz stab. Elevator servo lead 36" extention was used altho a 24" may have done the job, buy why run short? With a little luck, a dental pick, and needle nose plyers the servo lead was snaked the through the wing. the rudder servo pocket became a way point, then back inside under the retract mount, thru the oval slot in a wing rib being used for both the aileron and rudder leads, then under the wing spar tube thru another much larger oval laser cut hole and the out of the wing. Note I waited to install rudder servo and retract unit just to get this servo lead in place. Heat shink tubine was used on all servo extentions, cannot have these pull apart later on after all is glued together. At this point servos were testedfor operation. Tomorrow I add control horns and 2-56 linkage. Supplied clevis failed when I spread it open to attach it to a servo.

Also I used the Hitec flat lead for two reasons, 1) it was what was on hand, 2) the flat lead was used fo ID purposes. Hitec HD twisted leads on the ailerons, Futaba J leads on the rudders, air line for retract.

Servos are held inplace with #2 hex head screws, a pro-seller has the for sale here in RCU.
Cushion grip 7/64 allen wrench save wear on the hads driving in all those screws.
I bought it at Production Tool Supply a local tool shop supplier like J&L Industrial Suppy.

BadSplice 12-19-2007 01:17 AM

RE: Kangaroo-NitroPlanes-Assembly
Looking good. There sure is a lot of wiring in this plane. I am taking a stab at solid wiring all my servos for this one. (bought a 50' roll of servo wire) Seems like a good plane for it, since theres nothing to unplug and seperate.

Do you plan to use the plastic wheel wells included with the plane? I couldnt make them work with my mechanical retracts.

Crazy4Flight 12-19-2007 03:45 PM

RE: Kangaroo-NitroPlanes-Assembly
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if you really want to talk about wiring, my Kangaroo Jet makes this Kangaroo look easy.

cut your leads a litttle long and once you are assembled the cut to final lenght.

BadSplice 12-19-2007 04:55 PM

RE: Kangaroo-NitroPlanes-Assembly
Yeah jets are just Insane :p But sooo cool :D

Crazy4Flight 12-28-2007 11:52 AM

RE: Kangaroo-NitroPlanes-Assembly
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Setting up the Rudders you must get the contol horns above the max hieght of the ailerons or you will have an interference problem. Or like me have to move the horns up 3/4". Just 2-56 was used with great planes clevis. The very first supplied clevis, metal, broke when I opened it. So all spplied control rods and clevises were tossed into my Chinese ARF parts bin. A shame because they supplied lock nuts and fuel line keepers.

Pictures show wing dry fit assembled to do the rigging on all the control surfaces.
Because Delta Wings require a lot of elevator, I programmed my radio with elevons. And then useda P-mix of elevator to aux1. Aux 1 is the actual elevator on this plane.

I fly Futaba 9CAP

ch 1 aileron is the left elevon
ch 2 elevator is the right elevon
aux 1 {ch7} drives the real elevator

Crazy4Flight 12-29-2007 05:27 PM

RE: Kangaroo-NitroPlanes-Assembly
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Retracts Installed.

On the main struts I soldered a washer to the inside to prevent the wheel from binding on the bend radius. A wheel collar could not be used here because the axel portion of the strut whould have been too long and cold have hit the upper wing skin. The washer looks like a brake on the back side of the wheel. A flat was filed on the "axel" for the wheel collar also locktite was used on the set screw. Notches had to be cut in the wing sheeting and wheels to clear the spring loop.

Spring Air found the problem I had with one of the sticky mains and it was in todays mail. I did not expect it back so soon. The problem was the 10-32 set screww for holding the strut inplace was backed out of the trunion far enough the set screw hit the piston shaft just as the gear was nearly retracted. DOH!

I shifted nose retract unit over a bit to give me a bit more room for the steering linkage.

An air restrictor will be installed in the air system to keep the gear from slamming up and down.

Crazy4Flight 12-29-2007 08:43 PM

RE: Kangaroo-NitroPlanes-Assembly
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Wheel wells installed on the mains.
Greatplanes button head screws to hold them in.
3/8 square balsa added under wing sheeting for the screws to bite into.
Did not glue them in for I may need access to retract units.

opjose 12-29-2007 09:01 PM

RE: Kangaroo-NitroPlanes-Assembly

Could you post a detail of the nose gear steering linkage so we can see what you did?

Crazy4Flight 12-29-2007 10:51 PM

RE: Kangaroo-NitroPlanes-Assembly
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Well, I have not finished that yet. I had to lower (raise) the mounting surface for the spring air retract unit. The wheel well will have to be cut back to towards the tire.

Spring Air unit has a steer arm comming off the strut, a brass shaft is on the end of the steering arm, a clevis will hook onto the white nylon ear ( in the red oval ) that slide on the shaft as the retracts moves up or down, 2-56 rod will then go back to a servo not yet installed.

I should have all of the done later tonight after RED WINGS HOCKEY.

They said the plane was retract ready but never did say if they had retracts fo it to sell.
I am using Spring Air #305 flush mounts mad for the GreatPlanes Patroit kit.

Crazy4Flight 12-30-2007 12:52 AM

RE: Kangaroo-NitroPlanes-Assembly
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mounted Hitec 425BB servo
std 2-56 x12" rod and small nylon clevis
rod has vertical rise of 1.75" straight back
then slight angle towards center creating 1/2" offset parallel to first segment with clevis
the with 1" to go before servo slight bend to be parallel to first segment.
90 degree down bend to pass thru servo arm fast link to secure end.

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