WH-300 3-Amigos build thread (3 ways of doing the same thing)

[warren cross]

RC PATTERN FLYER, I have the same set up as u do. I have about 30 flights on mine, its one of the finest plane I ever flew. I too put 8611a on rudder as push pull. It was no big deal. I made a servo tray for both sides,cut some ultra coat our of one of the circles in the rear,and mounted them,put some balsa around the hole for the ultracoat to stick to,and recovered the hole. BUT I goofed! Thare are holes above and foward to whare I put mine. But if u use them u have to have longer control rods. Mine are 2 1/2in prolinks. Worked for me,and love it. Dont worry about matching the control rods,use ur sub trims and prolinks to even themup. I didnt need any adjustments. I am running a 3W150,MTW 110 cans,flexheader cut to 11 1/2in. 8611a all around,switched to dx7 radio (love it),powerexpander eq10,turbo reg,one 4800 lipo,one 6800 lipo. Never weighed it but guessing 41-42pds. Flies like its 30 pds. Hope this helps

[The Dirt Doctor]

	Quote: Originally Posted by RC_Pattern_Flyer
	San Antonio texas here, and as someone earlier mentioned, i don't se anywhere for the stab servo wires to penetrate the fuse.. guess that would have become apparent later eh Anyhow, off to work, going to try and set up the rudder tonight. having never done a double pushrod setup on the rudder, what is the easiest way to program the servos so they dont bind? i am using 8611a and flying Futaba 8U. Should i have one servo into each reciever or am going to use a matchbox setup? thanks in advanve. Chuck

Hey Chuck, we missed you at the SC IMAC F&J school last weekend up in Ft. Worth. Where were you?

Bobby

[randy racer]

guys keep up the good work and please post more pics, i should have mine in a week and watching this thread is a lot of help.

randy

[KrisW]

	Quote: Originally Posted by Shawn Berkheimer
	Kris, at the beginning of this thread you had stated that this would be your '07 IMAC aircraft. I am curious why you would program your aileron servos with so much throw and set you linkage ratios so agresssively. The way it is set up you will have to dial your rates way down and loose resolution. I am also concerned with the ratio and the stock plastic arm leading to flutter. Shawn

Actualy, Shawn, if you do NOT use a 1 1/4" arm the control rod will never go at a 90 degree angle to the trailing edge of the wing The hard point for the Rocket City horn is 1.25" off the center of the servo, so to get a 90 degree angle at the arm, to the horn, it's necessary to use the 1.25" or longer arms, and use the outer hole. I'd prefer that the hard point was only 1" off center, and that is how I would have set the plane up if I was building it from scratch. That way, with a 1.125-1.25" servo arm, the rod would move back and forth across 90 degrees to the hinge line, giving you a better angle and straighter load angle on the control horn. As it is, with the horn set where it is, you will get about 20-25 degrees of side-force against the horn and hinges of the aileron, pushing in an outward direction every time the controls move. this is very undesirable.

As for the servo arms flexing . . I've been using composite servo arms for 7 years now, and never had a flutter, failure, strippage, and only broken them in a crash. They are not as glitzy or glamorous as anodized aluminum arms, but they are just as stiff (to the point of failure) under the 190 ounces of torque these servos put out. By mounting the ball links on the underside of the arms, I also achieve a much better load geometry for the servo mounting pads and intermal bearing on the servos output shaft. Add in that lowering the ball link toward the wings skin allows a straighter average angle in the up-down plane for the pushrod going out to the control horn. I have about 10-15 degrees maximum angular deflection of the control rods with this setup, throughout the entire sweep of the servo arm. Left-right deflection is more, due to the placement of the control horn, but is still less than 20 degrees at 40 degrees of surface deflection.

Remember, I am achieving 40 degrees of throw in one direction with about 65 degrees of servo arm movement. I could dial up the ATV if I wanted and get probably 50-55 degrees of surface movement. Also, since I have a lot of thread left on the control horns, I can easily move the ball links outward, rendering less movement from the ailerons if I want.

I have a lot of set up options for dialing the plane in, once I get it flying. I'd want no less than 35 degreesof throw in each direction on ailerons, on high rates, and probably 25 degrees on low rates. This setup, as it sits, is pretty close to an optimum starting point for this plane. Only after flight testing will I know for sure what needs to be changed.

YES. . I know I need to put 2 more screws into the servo mount. . .

Pic1 shows the angles of the servo arm and pushrod for zero deflection of the aileron. It's barely 90 degrees, which is not desireable. You actually want the pushrod to angle inwards to the control horn slightly.

Pic 2 and 3 show the extreme angles of the pushrod at full deflection of the surface, and 100% ATV on the servo

Pics 4 and 5 show 50% throw on the Servo, about where I'd start for "IMAC Rates"

[KrisW]

I'd like to put in a shameless plug for a product here.

Ashlok Connectors:

http://dreamworksrc.com/catalog/inde...e19d0bd5096c18

These things are just THE setup for your aileron wiring.

The plugs come in 3, 6, 9, or 12 pin configuration, and you can either custom make your own cable with the provieded ends, or you can buy pre-pinned wire leads in a variety of lengths, and build a wiring harness that way.

Prices are VERY good.

I've been using the Ashlok connectors for 3 planes now, in my MX-2, my 35% Yak and now on this Extra. when putting the plane together, the self-locking connector simply slides and snaps together, making it impossible for the plug to come apart while flying. Then, depress the button and the lock disengages and the connector easily slides apart.

I HIGHLY recommend them to anyone with removeable wings or stabilizers. They do away with other connector mechanisms, are self contained, very well priced, and the already made wiring is both very large gauge and very well done. See the pics for an illustration of how it goes together.

[OverTemp]

	Quote:
	Actualy, Shawn, if you do NOT use a 1 1/4" arm the control rod will never go at a 90 degree angle to the trailing edge of the wing The hard point for the Rocket City horn is 1.25" off the center of the servo, so to get a 90 degree angle at the arm, to the horn, it's necessary to use the 1.25" or longer arms, and use the outer hole.

This is exactly why some of us were worrying about aileron geometry for 2 servo IMAC setups.

[KrisW]

	Quote: Originally Posted by OverTemp
	This is exactly why some of us were worrying about aileron geometry for 2 servo IMAC setups.

And which is why I am using 3. Look at the silly angles of the rods. . not my favorite way of doing things. Almost makes me want to drill new hard points.

[OverTemp]

Yeah... what a PITA. We could use 4" screws and 1.5" servo arms

My plane is sitting in the other room with the motor hanging off the front, yet I have no desire to work on it. I think the dark days are snow are getting to me.

Blah.

[KrisW]

	Quote: Originally Posted by OverTemp
	Yeah... what a PITA. We could use 4" screws and 1.5" servo arms My plane is sitting in the other room with the motor hanging off the front, yet I have no desire to work on it. I think the dark days are snow are getting to me. Blah.

Dude . .this is when you make a pot of coffee, remember to call in sick in the morning, and just go to it and have yourself a bonding experience with your plane.

i just checked the weather .. Thursday is shot, but Friday about noon things are gonna clear of, the wind is gonna drop and I'll be at the field ! !

[RC_Pattern_Flyer]

Bobby, just been focused n building and preparing for the TWO seasons. I have a usy contest schedule this year and i ge the oportunity to go to Toledo with 2DogRC and a new foamy line that they carry ( Aerojet Model Aircraft). Should be a fun and busy year.

Got through wih the rudder will post some pics in a bit.

Chuck Hochhalter

[RC_Pattern_Flyer]

Ok, so i built the rods according to WH and they worked great, i have used this before on pattern planes and had great results so trying it here was no big deal.

i do notice a little flex in the forward servo mounting area, wonder if anyone has had this and if i should firm this area up with some cross bracing maybe.

As for servo bind, little if any, i will meter them out tomorrow maybe and see how it goes.

Here is a simple picture of the ruder setup.

[The Dirt Doctor]

	Quote: Originally Posted by RC_Pattern_Flyer
	Bobby, just been focused n building and preparing for the TWO seasons. I have a usy contest schedule this year and i ge the oportunity to go to Toledo with 2DogRC and a new foamy line that they carry ( Aerojet Model Aircraft). Should be a fun and busy year. Got through wih the rudder will post some pics in a bit. Chuck Hochhalter

I hear 'ya Chuck. I've got almost too much going on this spring myself. What is the first IMAC contest that you're going to make?

Bobby

[RC_Pattern_Flyer]

Bobby, not sure yet, part of me wants to go to El Paso, i have family there but 8.5 hours drive.. killer!

We shall see.

Chuck

[KrisW]

So. . here I sit. .10 days after the plane arrived. . .watching the batteries charge up. A new OFNA power supply (to replace my frid Astro PS) powers the Fromeco charger. NICE Powersupply. . I highly recommend it.

All that's left to do . .Slice off all the excess screw lengths on the Rocket City horns, patch a small hangar-rash spot in the belly covering of the fuselage (OOPS), go over the covering with a heat gun, line the seam between the canopy and hatch with some white vinyl tape.

A couple of things I did. . Canopy mounting .. this thing fits perfectly, so all that needs to be done is glue it on. After marking the edges of where the canopy would go, I used a Wood Pecker to perforate the covering and underlying wood, then used a small smear of ProBond rubbed into the area as the adhesive. Rough the plastic of the canopy with some 100 grit paper, then put a small smear of ProBond on there as well, then screw it down on the 4 corners with the supplied screws, making sure it is TIGHTLY in place in front. I overlap the turtle deck slightly, so no glue was used back there at this stage. Then I used some heavy balsa sticks and masking tape to hold the sides of the canopy hard against the hatch sides, to help make sure there was a good glue joint.

After the probond cured up, I removed all the tape and sticks, then used thick CA on the inside of the back former, against the canopy to glue that part together. Wiped off with alcohol after a quick spritz with kicker, and the canopy mounting is done.

I've installed 2 side-side braces where the wings mount to the fuselage. The sides of the plane flex a LOT, and I wanted to stiffen this area to help keep the wings better aligned with eachother. By inserting a hard CF side-side rod between the front and rear of the wing roots, it makes this area very rigid, and the wings cannot move fore-aft at the tips under flight loads. I've seen a lot of planes crack formers and side plates in these areas, and this effectively stops that tendency.

I had to lengthen the pull-pull slots in the tail by doubling their length, because the rudder horns moved in and out, and increased tension on the CF rods as they tried to turn the corner. The offset servo arm keeps things tight at all times, rather than going slack on the trailing side, so it was necessary to lengthen the slots to prevent binding against the side of the fuselage as the rudder horns moved in and out in their arc of travel.

Wheel pants. .I NEVER use them .. but did this time. We'll see how long they last. I have about 8 pairs of Composite-Arf wheel pants on the shelf for replacements if necessary.

hole in the bottom of the cowl, for cooling air exit, is about 6" f-r, and 11" wide, with a 3/4" airdam/lip at the front. A simple bottom plate duct was installed on the front of the cowl, then after the work was finished and things sanded smoothed it was masked off and sprayed with dark grey texture paint. . Looks very nice like that. choke lever rod comes out the front of the cowl, due to the angle of the arm.

The ignition system has been tested and works fine. Fromeco 4800 pack with 5.5 volt regulator supplies power, through an MPI standard charge jack switch.

Fuel system uses a 50 ounce DuBro tank, with 5/32 Tygon line, and Slimline filler fitting.

Still need to string the antennas on the belly, but that's very easy to do.

Other than the iron work, and slicing the horns, the plane is RTF.

Fun build. . good plane . not too much bashing needed for the pipes. . I am HAPPY.

[Flatlandman]

	Quote: Originally Posted by KrisW
	So. . here I sit. .10 days after the plane arrived. . .watching the batteries charge up. A new OFNA power supply (to replace my frid Astro PS) powers the Fromeco charger. NICE Powersupply. . I highly recommend it. All that's left to do . .Slice off all the excess screw lengths on the Rocket City horns, patch a small hangar-rash spot in the belly covering of the fuselage (OOPS), go over the covering with a heat gun, line the seam between the canopy and hatch with some white vinyl tape. A couple of things I did. . Canopy mounting .. this thing fits perfectly, so all that needs to be done is glue it on. After marking the edges of where the canopy would go, I used a Wood Pecker to perforate the covering and underlying wood, then used a small smear of ProBond rubbed into the area as the adhesive. Rough the plastic of the canopy with some 100 grit paper, then put a small smear of ProBond on there as well, then screw it down on the 4 corners with the supplied screws, making sure it is TIGHTLY in place in front. I overlap the turtle deck slightly, so no glue was used back there at this stage. Then I used some heavy balsa sticks and masking tape to hold the sides of the canopy hard against the hatch sides, to help make sure there was a good glue joint. After the probond cured up, I removed all the tape and sticks, then used thick CA on the inside of the back former, against the canopy to glue that part together. Wiped off with alcohol after a quick spritz with kicker, and the canopy mounting is done. I've installed 2 side-side braces where the wings mount to the fuselage. The sides of the plane flex a LOT, and I wanted to stiffen this area to help keep the wings better aligned with eachother. By inserting a hard CF side-side rod between the front and rear of the wing roots, it makes this area very rigid, and the wings cannot move fore-aft at the tips under flight loads. I've seen a lot of planes crack formers and side plates in these areas, and this effectively stops that tendency. I had to lengthen the pull-pull slots in the tail by doubling their length, because the rudder horns moved in and out, and increased tension on the CF rods as they tried to turn the corner. The offset servo arm keeps things tight at all times, rather than going slack on the trailing side, so it was necessary to lengthen the slots to prevent binding against the side of the fuselage as the rudder horns moved in and out in their arc of travel. Wheel pants. .I NEVER use them .. but did this time. We'll see how long they last. I have about 8 pairs of Composite-Arf wheel pants on the shelf for replacements if necessary. hole in the bottom of the cowl, for cooling air exit, is about 6" f-r, and 11" wide, with a 3/4" airdam/lip at the front. A simple bottom plate duct was installed on the front of the cowl, then after the work was finished and things sanded smoothed it was masked off and sprayed with dark grey texture paint. . Looks very nice like that. choke lever rod comes out the front of the cowl, due to the angle of the arm. The ignition system has been tested and works fine. Fromeco 4800 pack with 5.5 volt regulator supplies power, through an MPI standard charge jack switch. Fuel system uses a 50 ounce DuBro tank, with 5/32 Tygon line, and Slimline filler fitting. Still need to string the antennas on the belly, but that's very easy to do. Other than the iron work, and slicing the horns, the plane is RTF. Fun build. . good plane . not too much bashing needed for the pipes. . I am HAPPY.

i need pics !!!