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Old Nov 29, 2011, 10:15 PM
More Motors, More Fun... :-)
nioa's Avatar
Phoenix, AZ
Joined Jan 2008
684 Posts
Build Log
Seagull Piper Twin Comanche 46 ARF

Just found this very nice looking Comanche Twin at Horizon. I suppose it will be awhile before it is in stock, but I am collecting info on it, as it looks very promising. I have ordered one, and will see how long it takes before I can start my build.

UPDATE: February 27, 2012: OK, Just got my Seagull Piper Twin Comanche 46 ARF.

Introduction:

I will be adding new build information to this thread here in Post's #1 and #2. My Electric Retract Installation is in Post #4. Anytime I do add new information I will post a message in the thread to let subscribers know that there has been an addition. The manufacturer's specs are immediately below. My contribution starts at "What's in the Box", followed by "My Preliminary Fit", sections below. The actual build will be shown in Post #2.

Constructive comments and input are always welcome. Please keep this thread on topic; namely the Electric Build Version of the Seagull Piper Twin Comanche 46 ARF.

If you are interested in a Nitro build, Craig has a Twin Comanche thread on RC Universe for you. Check it out, as there is some good building there too.

I am not going to be rushing to put this plane together. I have other plane commitments, but I will announce new information to the thread as I go along; that way if you are subscribed, you can follow along too. Check back here at posts #1, #2, and #4, to keep up-to-date. If there are any questions I can answer I will be happy to do so.

Nick

Link to Manufacturer's website.



Seagull Piper Twin Comanche 46 ARF Specifications:

Wing span: 76.4in (194cm).
Wing area: 830.8sq.in (53.6sq dm).
Weight: 10.6-11lbs (4.8-5kg).
Length: 51.3in (130.3cm).
Engine: 0.46-0.55cu.in, 2-stroke; or 0.72-0.82cu.in,4-stroke.
Radio: 6 channels with 10 servos.

Electric Conversion Option figures from the Manual:
Model size: .35-.45 size models
Motor: 35mm, 830 kV
Propeller: 10x7E
ESC: 50A
Lipo Batteries: 4 cell 3200mA

Wheel Well and Nose Doors: SEA13413
Optional Mechanical Retract Set: SEA13414

ARF Features:
  • The control surfaces, including the ailerons, elevators, and rudder, are pre-hinged with hinges installed, but the hinges are not glued in place.
  • Electric motor mount "kit" is provided.

Here's What's In the Box:



Nice colorful box, arrived in good shape.

Covering is tight. No wrinkles. Everything was very neatly packaged in plastic. Nose Cone and Nacelles wrapped in paper and plastic. No cracks, no chips, no broken parts. Scroll on down to see the attached images.

Preliminary Fit and Features:



Whenever I get a new ARF, I always put the major parts together so that I can see if the kit is OK, and whether or not to proceed. The photos below starting at [image 18] are of the plane temporarily assembled with clear tape. So far everything fits, and it looks like there are no major defects in the kit.

The wing spar fits perfectly, and everything lines up, is square, and fits as it should. I am not too crazy about the cardboard wing tube, it really should be fiberglass, but OK. The bottom access panel in the fuselage is a little too tight, but that's an easy fix.

Not mentioned anywhere else, is the fact that this plane has a full instrument panel [image 20]. The pilots were a nice surprise too. There are a lot of nice details, like faux lighting on the rudder, nose cone, and wing tanks. The little antenna's are a very nice touch too.

Servo blocks attached to the servo covers for the ailerons and flaps are also installed in the wing! This goes well with the pre-fitted and pre-hinged flaps, ailerons, rudder, and elevator. As stated above, the hinges are not glued in place. Also nice is that the covers are in the correct orientation of the servo arms for the ailerons and flaps. The servo covers have holes pre-drilled for the mounting screws. Also, the tray that the servo mounts on for the mechanical retracts is removable. It is held in place with a socket head screw and tabs.

I did not expect to see spinners, but they are in the box too. They are 2-1/4" white plastic spinners. I will replace these with aluminum spinners, but it is nice to see them in the box.

Another amazing thing was the use of steel clevises. The control rods are 2mm and they have 2mm nuts to lock them to the clevises. I like 2-56 hardware, and I usually always replace the kit hardware with 2-56 or 4-40 in almost every ARF I have built, but I will be using the provided 2mm hardware. The nose gear, rudder, and elevator control rods are pre-installed for you.

A tail skid is included!

The quality of the hardware, looks good, and complete. The control arms are screws with control horns added. In the hardware bag, strips of covering are included to finish off those seams. [image 30] shows the hardware. The engine mounting hardware is not shown, but included with the mounts.

The wheels are 2-1/2" in diameter. They look nice. I usually replace the stock wheels with Dubro wheels. They are not hard rubber, more like foam with a rubber skin.

There are 2 nylon wing bolts per wing. A total of 4, and the main compartment cover is held in place with a small 4mm nylon bolt.

Two very tiny fuel tanks are provided. They are not marked with capacity, but they are about 3.4 inches (86mm) x 2.3 inches (58mm) x 2.2 inches (56mm). One holds 8 ounces of fluid, about 235cc. The empty fuel tank with hardware weighs 1.8 oz (50g). The tank with liquid weighs 279g. A typical 0.46 engine weighs in at about 489 grams.
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Old Nov 29, 2011, 10:18 PM
More Motors, More Fun... :-)
nioa's Avatar
Phoenix, AZ
Joined Jan 2008
684 Posts
The Build



Components:

Brushless Outrunner electric motors: Emax BL3526/04 860 kV Brushless Motor
ESC's: Hobbyking Plush 80, BEC's will NOT be used.
Motor Batteries: Two (2) Haiyin 4S 5000 25C 545 grams each, (19.2oz), 145 mm x 55mm x 35mm.
Receiver Battery: LiFe 2S 6.6v 1100mAh (A123)
Retract Battery: LiFe 2S 6.6v 1100mAh (A123)
Propeller: APC 11x7E
Servos:
Hitec HS-485HB : Ailerons, Elevator, Rudder (4)
Hitec HS-485HB : Flaps (2)
Hitec HS-485HB : Nose gear steering (1)

Futaba R617FS 7-Channel 2.4GHz FASST Receiver
Futaba 7C 2.4GHz Radio System (Flaps are variable on this system)

The weight of all the airframe components as it comes out of the box:
Electric: 3217g = 113.5oz = 7.1 lbs
Fuel: 3493g = 123.2oz = 7.7 lbs.

I plan on installing the stock fixed landing gear temporarily. Later on, I will install Electric retracts. The mechanical retracts for the main gear use one servo for both wings, that would make it interesting to transport the plane without removing the wings. If you did have to remove the wings, you would of course, have to remove and re-adjust the linkages on the servo each time. Fun.

Build

I'm going to take the traditional path and start with the hinges. I hate to hinge. What is great is that all of the hinges have been done for you. Every bit of it, except gluing. I actually enjoyed doing the hinges for this plane. It was nice to see how well it was done at the factory too, everything lined up perfectly.

Right now, the goal here, of course, is to get the plane together as much as possible to be able to determine where the electric power components will be placed.

The Hinges:

Tighten the covering - this is the last chance to iron out imperfections in the covering on the hinge line before gluing.

I use BSI Insta-Flex flexible thin CA. This has low odor, which is a big plus, but this glue does take a bit longer to dry than regular CA..

Watch your hinge gap, centering, and clearances. I used to use the "pin" method to space the hinge, but now I deflect the hinge and glue it in place. I find that this prevents too large a gap that the pin method can sometimes make in the hinge. I also "tack" the CA hinge to one side of a control surface before I insert it for final gluing. This keeps the hinge from moving out of place. Use plenty of CA, and use a cloth or paper towel to absorb any excess CA on the surfaces.

Wipe off excess CA, especially when gluing the flaps. You don't want to glue the flap in the up position do you? Move the control surface as soon as you are finished applying CA.

Also, I use a piece of low-tack tape to mark each position of the CA hinges. This makes it easy to direct your glue nozzle precisely to the hinge. Because the hinge is white and the covering is white, and the gap is small, it is easy to lose the position of the hinge.

Horizontal Stabilizer: While you are doing the rudder and elevator hinges, look carefully through the covering at the trailing edge on the elevator. In the middle of the surface is printed "TOP". It is easier to see in a bright light. You want to install the stab right side up when the time comes, right? If it is not printed, then look at the covering to determine which side has had covering applied last. That surface is the top. Mark the top surface with low tack tape.

Do the pull test - better to come off now than in the air!

Servo Installation



The servo covers for the ailerons and flaps have holes pre-drilled in it. Use a 1/16" drill bit. I thought the screws provided were a little too big looking so I opted for #2 screws with washers. Use the cover inverted as a guide for drilling.

For mounting the servos I like to use the "Dead Center" tool to locate the holes to be drilled to mount the servo's. This tool is a must have, it produces very nice evenly spaced marks for drilling with professional results. Much better than trying to do it "by eye". The Hitec HS-485HB servos I have chosen fit the aileron, flap, rudder, and elevator bays precisely without any trimming needed.

Once the servo holes have been drilled in their covers or trays, use thin CA to "harden" the wood the screw grips.

I will be making a custom wire harness that the servos/power will connect to. Instead of having to plug-in many individual servo connectors, I will combine those to make one connector for each wing side. In case you are wondering why the photos above have the servo leads coming back out the servo covers, it is because the servo connectors will have to wait until later in the build to be finished.

While drilling the holes for the rudder servo, I cracked one side of the E/R servo tray on the fuselage wall. The tray and how it is mounted is not very strong. I recommend that you reinforce your servo tray.

I placed 1/4" square hardwood (3-3/4" long) underneath both sides to reinforce the tray. I used a spreader clamp to help hold the pieces in place while the epoxy dried. It is kind of an awkward clamping situation, so I was not able to use the usual triangle stock. I also put 1/8" plywood under the servo rails to give the servo screw more to "bit into".

I opted to install my steering servo in the nose retract bay, instead of using the rudder servo for steering. Since I have the extra channel, I like to use it since I don't have to worry about getting the mechanical centering perfect, as I can use the trim on the steering channel to center the steering wheel. The electric retracts I plan to install later can also use this servo. Originally the servo in the nose bay was to activate the mechanical retract in the nose.

The hole for the steering servo mount was too long so I had to cut a piece of wood to fill in the gap. I also added 1/8" ply underneath this tray as well to make it stronger.

Control Linkage

At this point, I have the control arm hardware in place temporarily. I want to see how the control throws are going to work out before committing the hardware to epoxy. To get the maximum mechanical advantage and resolution from the servo, I want the servo arm to be as short as possible and the control arm of the control surface to be as long as possible. The ailerons, for example, will have the required 12mm up/down throw if I use the inner most hole of the servo arm with the maximum length of the aileron control arm.

I'm going to leave the rudder and elevator control arms for later, but the assembly is exactly the same as the ailerons and flaps.

The holes for the control arm hardware are pre-drilled and pre-marked. The CA hinges are good quality. Cut a small "circle" in the covering to place the hardware. Underneath the covering you will see that the control arm screw hole has been drilled for you. How easy is that!

Place thin CA in the holes that are drilled in the wing for the control arms of the ailerons and flaps. This will harden the wood. Allow the CA to thoroughly dry. Install the crowned washer and 3mm x 35mm long screw on the top surface and hold in place. Place epoxy on the opposite side so that the wood surface, screw threads close to the wood surface, and the inner part of the flat washer are coated in epoxy. Use an up and down motion to work the epoxy into the exposed wood hole. When you have good coverage, slip on the 3mm nut and tighten. Remove excess epoxy with alcohol.

I found that the control arm horn needs to be drilled out with a #49 bit to clear the 2mm control rod. The clevis hole in the servo arm needs to be drilled out with a #52 bit. It is snug, and using these bits results in slop-less motion.

My flaps are able to deflect 40mm. To set the linkage, I centered the flap servos, and adjusted my linkage until I had 20mm down flap.

The nose gear steering linkage required a bit of experimentation to find the right dimensions to fit correctly. My third attempt was successful. I used 2-56 rod, and my favorite ball links. I am not sure that 2-56 rod is strong enough, I may have to go to 4-40 rod. The bends made in the wire, allow for further unwanted bending on a hard landing, but that may not be a problem, as any bending would protect the steering servo.

On to the elevator: Mark the R/E servo tray where the rudder servo and the elevator servos go. Temporarily put in the control rod for the elevator. This will be a guide for the next step.

Temporarily install the vertical and horizontal stabilizer to determine which side the control arms should be. I installed the elevator control arm when I installed the horizontal stab, I also installed the rudder control arm when I installed the vertical stabilizer, but that's skipping on to the next section.

While the horizontal stabilizer is in-hand, make the center markings for reference and covering removal in the next section. I hope you still have your drafting triangle, it will come in handy about now. While the rudder is in-hand, consider installing the anti-collision lights on the rudder now. I like to use hot glue, otherwise use thick CA. Follow the manual for these steps and the next section too.

Horizontal / Vertical Stab Installation:



This is pretty straight forward. The manual can be followed here. Remove the covering from the bottom of the horizontal stab and mating area's on the fuselage. Epoxy and clamp. Don't forget to install your tail skid with epoxy.

Once that is dry the vertical stabilizer is next. Again, the manual is fine here.

The Motor Box



The motor box has a piece of plywood that the motor attaches to that allows you to slide it back and forth so that you can fit the length of the motor to the fiberglass nacelle. I did not use this feature. I glued this sliding mount as far aft as it would go. I will use spacers to position the motor to the nacelle opening. I did that because if I need to change out motors, I can do so without having to be limited by motors that are the same length or shorter. The second advantage is that the forward and aft positions of the mount define the down-thrust and right-thrust. Intermediate positions require more care in placement.

To make the mount as strong as possible, I used 1/4" hardwood triangles that were placed at stress points in the motor mount area and glued with epoxy.

I went over the entire motor box assembly joints with thin CA.

A cross member was added at the top of the box to stiffen it, as it was possible to visibly twist the box with moderate pressure. I used a piece of 1/4" hardwood here too. The reinforcements I used only added 18.5 grams to each of the boxes. The box is now very stiff and ready for installation on the wing. If you have the time, and want a really strong box, you could epoxy 1/4" balsa triangle stock to all the joints aft of the motor mount. I also added two cooling holes in the aft part of the box.

Attachment of the motor box to the wing box is straight forward. I sanded the common surfaces lightly for better adhesion, wiped away the dust, applied epoxy, and clamped.

The fit of the nacelle to the motor box, is excellent. It is a bit snug getting the nacelle on, but it does go on easily enough.

Preliminary Battery Placement Tests for CG

I spent a good part of the morning setting up the aircraft so that I could determine the best placement of the battery. There are two possible locations: (A) placing the batteries in the fuselage, or (B) having a battery in each nacelle.

For testing, I used 700g 5S 5000mAh batteries, and a 140g LiFe battery for the receiver. Without any batteries, the plane is slightly nose heavy. You should note that there is a compartment in the tail for the receiver battery.

(A) With the batteries in the most forward position in the fuselage (you can see that in image 25 in post 1 above), and the LiFe battery in the middle of the fuselage, the plane balanced. The range of balance is excellent. Use of lighter batteries was accommodated by moving the receiver battery more aft. If needed, you still had plenty of range by utilizing the tail compartment.

(B) Using the nacelle's to mount the battery resulted in a very nose heavy plane. The Life battery had to go into the tail battery compartment, and ballast had to be added to the tail in order to balance the plane.

I originally wanted to go with the batteries in the nacelle's. It would be nice to have hatches on the top of the plane in which to make battery changes (I had a neat idea for how to cut those hatches straight and professionally too, but...). The downside to (B) is the lack of adjustment range you have before you have to add tail ballast. You would also have reinforce the motor box quite a bit to make it strong enough for the weight of the batteries. That reinforcement would of course, make the plane even more nose heavy.

There is plenty of room in the forward part of the fuselage for the batteries. They would slide in under the wing tube. The distance of the wires from the ESC to the battery is about 12 inches, when the ESC is mounted as far aft in the motor box as possible. This wire length is about what my other planes have. For those concerned about ESC to battery wire length, keep in mind that this is a relatively low voltage, low power system. It is those high voltage, high power systems that the wire length becomes an important issue.

Motor / Nacelle Installation

Nacelle to Wing Mounting

I wanted to increase air-flow to the motor so I removed the faux opening decals in the nacelle. To clear the opening quickly, I drilled holes to remove material, and then used a file to shape the opening.

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Description: Nacelle finished (Click on image for enlarged image)

Next step is mounting the nacelle and locating the holes that need to be drilled into the motor blocks to mount the nacelle. There are probably a lot of ways that you could do this, but I chose a simple stick and marking technique.

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Description: Location of block mounting holes (Click on image for enlarged image)

Remove the motor if it is mounted, and tape the nacelle in its location on the wing using low-tack tape. There is a left and right nacelle. Be sure that the tape "pulls" the nacelle at the aft end of the nacelle and wing trailing edge.

Using paint sticks, I split one stick down the middle to make a "skinny" "left" and "right" stick. They are inserted into the left and right openings until the meet with the nacelle mounting block. They are then used to make markings with another reference stick that I placed on the front of the nacelle. The mounting block for the nacelle is 1" x 2". I want to place the holes in the middle of the block, or 1/2" in. A mark 1/2" further forward represents the distance "into" the block and marks the place where the hole should be drilled.

Use low tack tape on the nacelle to allow you to make markings on the outside of the nacelle to mark the location of the drilling points. I used another piece of tape that I placed marks on for the 0 and 2" point that represents the block length, and marks at 1/2" and 1-1/2" that represents the actual drilling point. Peer into the openings to get the "height" of the blocks, and by eye, transfer that to the outside nacelle markings.

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Description: Good placement of holes. (Click on image for enlarged image)

Use a flashlight to double-check your locations of the marks before actually drilling. Keep in mind that the nacelle is tilted slightly compared to the wing inclination, so make sure that when the wing is level, your two marks along the block are level as well.

Once you have drilled the holes in the mount, use thin CA to harden the holes. I used a 1/16" bit for #2 screws and a washer. I also enlarged the holes in the nacelle's so the screw would pass easily through it.

To finish the nacelle mounting, drill a hole in the aft part of the nacelle to mount it to the wing. I would also suggest that you consider a reinforcement to the aft hole on the nacelles. I used a small steel plate with a small hole in it. Epoxy was used to glue the plate in place. CA the mounting holes on the wing to harden them.

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Description: Nacelle hole reinforcement

Motor Mount to Motor Box Mount



In order to perfectly align the motor shaft with the nacelle opening, I made a 42mm centering guide out of Depron. A circle cutter was used, and to make the center hole in the Depron, I used a sharpened piece of 5mm brass tubing which matched my motor shaft diameter. Don't worry if you don't have a piece of tubing that matches the diameter of the motor shaft, you can use a slightly smaller tube like a 5/32", and that will work just fine, the Depron will "stretch" a bit.

On a soft surface like a carpet, sit the wing vertically on the trailing edge. Gravity is going to hold the motor in place while the motor mount locations are marked on the motor mount box.

Place the motor with its motor mount attached in the approximate location on the motor box.

Slide on the nacelle - a slight left and right, back and forth motion will help ease the nacelle in place on the wing.

Position the motor shaft in the center of the nacelle opening using the Depron guide as a way to peer down and confirm center position.

Carefully remove the nacelle without allowing the the motor to move out of place. It's not as hard as it seems, the motor's weight will hold it in place.

With the nacelle off, use your Dead Center Tool to mark the four motor mount locations. Once the pilot holes are drilled, use a small screw (like a #2) to attach the motor to the wing box. Put the nacelle back on and check to see if the motor shaft is still centered in the nacelle opening. If the shaft is not centered, the pilot holes you drilled are still small enough to not cause problems, and let you make better centering marks.

If the fit is good, remove the temporary screws you put in, and drill holes for blind nuts. I used 4-40 hardware. Install the blind nuts in the wing box, and use thin CA to fixate the blind nuts.

ESC / Motor Installation:

Wire the ESC with the appropriate battery and motor connectors. Remove and insulate the red wire from the signal cable as that will not be used. I placed the ESC on a triangular piece of EPP to mount it inside the motor box. Tie down the motor and esc wires.

Mount your motors. I used 4-40 hardware with 3/8" spacers. Use thread-lock.

Also note in the last photo is the kind of "chain" I use to help run the wires through the wing. This is standard lamp pull chain. It is fantastic for working its way though tough to run locations.

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Description: Motor wire lead hold-down. Lamp pull chain (see article text)

Electronics

To tame the large number of connections that come from the wing, I use a custom connector. This connector is like the standard connector we use, but is wider to accept more wires (See photos). I use a header board to plug the wing connectors into. I call this a "Y" - Board. The "Y" is a perf-board that has conductors running the length of it for each wire. On each end is a header. In this case because of the complexity of the electronics, I chose to put the ground and signal wires on one header and the positive supply on another header.

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Description: Electronics

An Assan Gear & Door Sequencer was used to operate the nose gear and doors. I used a separate battery for this as the operation of the Electric Retracts has a definite "spike" when operated. I did not want this power surge to be seen by the receiver which has its own battery.

I used the removable platform in the compartment to place the receiver and Door sequencer on the "bottom" layer. The Y-Board, Interface board, and Voltage Monitors sit on top of that.

A "EC3 Connector Interface Board" is used to connect the LiFePO4 batteries to the receiver. This gives a good hard-point to mount the battery wiring. There is power decoupling and a place to attach the wires for the ON/OFF switch.

If you go to my RCGroups Blog you'll see a Wiring Diagram for the PTC, Motor Power Measurements, and other items of interest.

Battery Mount

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Description: Main batteries mounted.

The LiFePO4 batteries were mounted with Velcro Brand fastener. Just a loop, nothing special. A piece of regular Velcro was placed in the bottom of the compartment, and two-sided loop Velcro was also used. Both LiFePO4 batteries are taped to each other and then placed in the Velcro loops.

The main batteries have a two holders that are made from 1/16" plywood. See the photos for details. This type of fastening system is very strong, and takes advantage of the shear resistance of Velcro. The holder is very easy to install and remove. You place one end in, and fold the holder down against the battery, then put the other "tab" in place. Velcro on the bottom of the compartment is used to assure that there will be a good hold on the battery.

Main Hatch Conversion

I moved the latch from the front of the fuselage to the rear. This was to help give better clearance when you change the batteries. Pegs were installed in the front, and I created a latch for the rear.

The latch was made from 3/32" rod, a 3/32" wheel collar, 4-40 rod for the handle, and a spring. Make sure to cut a "flat" into the rod so that the threaded part of the handle has a good grip on the rod. CA the joint to make sure that it will never come apart.

The existing hole in the front of the cover was hidden with a small round piece of covering that I had from cutting open the wheel wells.

Trim

Wheel Wells: Cut with a sharp heavy-duty scissor. Sand to final dimensions for smoothness. Use medium to heavy CA to glue. Epoxy does not adhere well to this type of plastic.

Aft Nacelle Trim: Cut with a sharp heavy-duty scissor. Shape with a sanding block. Instead of just putting glue on the edges of the pieces, I like to place a balsa block inside the piece to make sure that it will never fall off in flight. Cut small balsa blocks. Roughen the inside surface of the trim piece. Use medium CA to attach the block to the trim. Sand the blocks to conform to the angles of the wing. Remove a spot of covering where the block would be positioned, and use thick CA to glue it in place. I also use a soft brush to place thick CA along the outer edges so they adhere to the covering without making a mess.

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Description: Trim with blocks sanded

Decals: These are pre-cut, you just need to place them. A good way to do the larger decals is with a gallon on water mixed with a teaspoon of dish detergent. The soap will keep the decal from being too sticky, and will let you move the decal around for perfect placement. The water also helps keep bubbles to a minimum. Squeegee out the excess water, and you're good to go.

Completed Weight:

Air frame = 4775g = 168.4 oz = 10.5 lbs.
plus Two 4S 5000 mAh 25C Lipo's = 1082g = 38.2 oz. = 2.4 lbs.
plus Two A123 1100 mAh batteries = 202g = 7.1 oz. = 0.4 lbs.

Total Air Up weight (AUW) = 6059g = 213.7 oz. = 13.4 lbs.

Note that the plane can also use smaller batteries then the one's that I used. 4S 3300 mAh's would be fine. Typical weights for the 3300 would be about 375g. 375 + 375 = 750g = 1.75 lbs, a weight reduction of 0.65 lbs.
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Last edited by nioa; May 22, 2012 at 12:28 PM.
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Old Feb 06, 2012, 03:37 PM
Horizon Hobby Employee
United States, IL, Mahomet
Joined Jun 2006
595 Posts
The manual is incorrect; this model does not include retracts. Mechanical retracts are an option, there are wheel wells built into the airplane. These wells are just openings, molded inserts are an optional part.
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Last edited by Craig Greening; Feb 20, 2012 at 11:25 PM.
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Old Feb 06, 2012, 04:08 PM
More Motors, More Fun... :-)
nioa's Avatar
Phoenix, AZ
Joined Jan 2008
684 Posts
Electric Retract Installation

Original Post:
Thanks for that info Craig. Very helpful. Actually I wouldn't want the mechanical retracts anyway unless there was no way to get electric retracts in there, and at this point I can't see why not.

What is nice is that there are wheel wells. That in my mind is something that finishes off the plane very nicely. Nick


================================================== ==

I'm going to commandeer my own post so that I can add my electric retract installation to a post separate from the main build.

Here are the main options for the Twin Comanche Landing Gear:
  • Use the original stock landing gear. (A good option)
  • Install the mechanical retractable landing gear system. This would be OK, but in order to get the batteries in, you would have to give up using the rudder servo for steering, and have another servo for steering up front. Plus, you would have to disconnect the wing retract linkage (and most likely have to adjust it) every time you want to remove/install the wing. Unless, of course, you transport the plane intact.
  • Install Electric Retracts. That is the topic of this discussion.

E-flite 60-120 Electric Retract Installation.

I used E-flite 60 - 120 Tricycle Electric Retracts (EFLG430). There are many other retracts you could use, and different ways of installing the retracts; this is my installation:

Mains: The mains require you raise the retract mounting platform so that the retract body will clear a former that runs through the wing. I did not want to cut into the wing to reduce the size of the former. I raised the mounting rails up with a 1/2" x 1/2" basswood block. This block is about 47mm long. I had to cut off a side of the block so that the retract body would fit in the opening. The finished size is about 0.5" by 0.43" (12.77mm x10.89mm). The rail does not have to be a full 1/2" high, I chose the 1/2" because I had that size handy. You could lower the rail a bit if you wanted to and still have good clearance for the retract wiring.

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Description: Main Retract mod. Note the reinforcement block underneath the mounting rails.

To make the mounting rails as strong as possible, I placed a block of hardwood underneath the mounting rails. This fits snugly, and is held in place with epoxy. I used a screw as a handle to help position the block as it is a little tough to get in there. Once glued in place the screw was removed. This hardwood block also has blind-nuts in it to fasten the retract body down.

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Description: Paint and trimming to be done.

The retract is held in place with two blind-nuts, and two #8 x 1-1/4" screws. The image shows the #8 socket head screws used, and their location. A total of four screws are used to hold the retract in place. The other two screws are #6, 1-1/4" hex head wood screws. Alternatively, you might be able to use threaded inserts instead of the wood screws.

Nose Gear
:

The nose gear mounting blocks sit too high to be used the way they are. They have to be "lowered" into the body, so that the wheel will have enough clearance for the doors. I placed the retract body on the blocks and made marks, and drilled holes, so that I would have a reference for later on.

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Description: The nose gear compartment. Remove all the blind nuts.

Remove all of the existing blind-nuts. A hole was cut into the forward firewall so that a rasp file could be used to quickly sand the blocks. Final sanding was done carefully to make sure that the new mounting area was level. This was done with 200 grit on a piece of ply that was about the same width as the opening. A hole was drilled to allow the wire underneath the retract to have clearance.

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Description: An access hole has to be made to allow you to sand down the blocks. Name: PTC-ElectricRetract-3825.jpg
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Description: Final sanding to make level. Name: PTC-ElectricRetract-3831.jpg
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Description: Hole for wiring clearance.

Another access hole was cut into the firewall so that a reinforcement could be placed under the new mounting area. You may be thinking that this is going to weaken the firewall. It would, but we're going to take care of that later, with a new firewall cover. Also, since no one is going to see this area, don't worry if your cuts are not too pretty!

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Description: Another access hole to add a reinforcement underneath. Name: PTC-ElectricRetract-3830.jpg
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Description: The reinforcement plate that will go underneath the mount. Name: PTC-ElectricRetract-3832.jpg
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Description: Ready to epoxy the reinforcement plate in.

To make the "Cap" or cover, for the firewall, trace the outline of the front fuselage onto a piece of paper. Transfer that tracing to a piece of 1/8" plywood. Cut "inside" the line by about 3/32 to 1/4 inch. Attach the new cap to the firewall with epoxy held in place with temporary screws. Do this step last, when everything else is completed, as you will need access to the fuselage.

Nose Gear Doors

The nose gear doors will be controlled by an Assan Gear & Door Sequencer. I really recommend that you create a mock-up of the door and retract mechanism. I used paint sticks glued together to form the pocket of the fuselage that the gear sits in. This way, you can work out all of the door linkage and timing steps needed without having your retracts crash into your doors, etc.

Two 9 gram servos were used to actuate the doors. Cut an outline of the servo in both wells. You can use a #11 knife to make the holes. Carefully rock the knife back-and-forth and it will cut through. The "chamber" that I mounted my servo's in does not have any access holes in it. You will have to drill a hole in the aft wall of that chamber in order to pass the wire back to the controller.

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Description: Cutting servo access holes. Name: PTC-ElectricRetract-3834.jpg
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Description: This compartment does not have any way to get a wire to the controller. You will have to drill a hole in the aft wall. Name: PTC-ElectricRetract-3838.jpg
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Description: Door control arms. The wire makes this mounting system very strong.

The right side servo has to be recessed into the wall more than its mounting ears allow. This is to give the wheel axle better clearance. I cut off the mounting tabs of the right servo, and used a piece of wire to act as a guide so that servo would not fall into the hole when I glued it in. The guide also makes it easier to glue the servo in, as it helps align the servo during the gluing process.

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Description: 9 gram servos. One with mounting tabs removed. Name: PTC-ElectricRetract-3837.jpg
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Description: Guide for servo. Name: PTC-ElectricRetract-3839.jpg
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Description: View of door servo

Hot glue will be used to mount the servo's and the door control arm linkages. The door control arm linkages were made from a cut-down servo horn, and then sanded so that it would be thin enough to pass into the Dubro Micro E/Z Link 849 for .032 wire I used. A "Z" bend is used on the servo control horn.

Make sure when you are ready to glue in the doors, that you coat the hinges with oil or petroleum jelly. You don't want the epoxy to jam up the hinge.

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Description: Another view Name: PTC-ElectricRetract-3842.jpg
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Description: Overall view. Test fitting. Name: PTC-ElectricRetract-3844.jpg
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Description: Overall view. Test fitting. Doors open, gear up.

The Assan sequencer lets you adjust the open and closed position of the doors. It also lets you set a delay. It also acts as a reverser so that both doors operate in the correct direction. With your transmitter channel set to normal (not reversed), set up the controller. I made up a Assan Sequencer Manual, you can find it here. Your setup will of course vary, but mine is:

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Description: Assan Sequencer Programming

Door 1 is on the right side of the aircraft, door 2 is on the left side (as viewed from the usual pilot position).

Here are the retracts and doors in operation:

Piper Twin Comanche Electric Retract Operation (0 min 11 sec)
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Old Feb 06, 2012, 04:44 PM
Horizon Hobby Employee
United States, IL, Mahomet
Joined Jun 2006
595 Posts
The wheel wells are covered over but easily opened for use with retracts. We have not yet installed retracts but my colleague who is assembling the model believes the E-flite 60-120 tricycle gear will go in without too much work.
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Old Feb 06, 2012, 11:40 PM
William from Windham NH USA
saltydog56's Avatar
United States, NH, Windham
Joined Apr 2005
160 Posts
Greetings from the North East

Craig I would be interested in the quality of the balsa and if you plane came with any underlining dammage to the balsa structure.

I have purchased in the last year the T6A-Texan II, the Percival Mew, Gull and my latest the Ryan Navion.

The thing that always bites me again and again is, I love the subject matter that Seagull models. But the Quality of there kits when it come to the balsa is sub par.

All three kits had structual dammage to the balsa under the covering. Horizon replaced the wings on the T6.

Three fusalages till they finaly got it right and one wing set on the Mew gull.

And now a fuse and cowl for the Ryan The ryan the cowl and the fuse stripes did not match no matter how I tryed mounting it and the bottom of the fuse was crushed.

Wings where dammaged on the T6 at the root area.

Now get this one I ordered A Mew gull from my local shop.
We opened the box after removing it from the cardboard shipping box to find the fuse crushed!!! Not only was the canopy completly smashed but the structure to the bottom of the fuse crussed..

No dammage to the box at all crisp and clean as all getout
upon further inspection one of the wing pannels was crushed.

Ok no problem will get you a new wing set and a new fuse this went on for three weeks. receved the wing set boxed the shipping box was crushed no dammage to the wing set!!

Every fuse total of three had damage to the air frame, a total of three till they finaly got it right. This was for the Mew Gull

And now I have all these broken parts for they did not want them shiped back

Hats off the the service department, they whey verry kind and helpfull to the best ability. But now I shy away fom any Seagull Kits.

So how is the Quality of this new kit

William
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Old Feb 07, 2012, 12:00 PM
More Motors, More Fun... :-)
nioa's Avatar
Phoenix, AZ
Joined Jan 2008
684 Posts
Quote:
Originally Posted by Craig Greening View Post
The wheel wells are covered over but easily opened for use with retracts. We have not yet installed retracts but my colleague who is assembling the model believes the E-flite 60-120 tricycle gear will go in without too much work.
Any info you can pass on from that build would be greatly appreciated. Especially power system details. Thanks Craig!

Nick
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Old Feb 08, 2012, 12:28 AM
whiirrrrrr
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United States, TX, Houston
Joined Nov 2011
785 Posts
I love the plane! I wonder why they don't call it a 310. I guess they can't use the name "cessna".

I'll be following!
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Old Feb 08, 2012, 08:24 AM
Horizon Hobby Employee
United States, IL, Mahomet
Joined Jun 2006
595 Posts
Hi Nick,

The model we're completing has Evolution 2-strokes, but we are hoping to build and electric version also.

Craig

Quote:
Originally Posted by nioa View Post
Any info you can pass on from that build would be greatly appreciated. Especially power system details. Thanks Craig!

Nick
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Old Feb 08, 2012, 08:24 AM
Horizon Hobby Employee
United States, IL, Mahomet
Joined Jun 2006
595 Posts
Because it's a Piper, not a Cessna...

Quote:
Originally Posted by srt8madness View Post
I love the plane! I wonder why they don't call it a 310. I guess they can't use the name "cessna".

I'll be following!
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Old Feb 08, 2012, 02:54 PM
whiirrrrrr
srt8madness's Avatar
United States, TX, Houston
Joined Nov 2011
785 Posts
Quote:
Originally Posted by Craig Greening View Post
Because it's a Piper, not a Cessna...
LOL!! That would explain it. When I search I included the word seagull not realizing it was the model name, and when only model airplanes showed up I thought it was the cessna. They look an awfull lot alike
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Old Feb 20, 2012, 05:50 PM
Registered User
Denver, CO
Joined Apr 2009
36 Posts
Some BIG Problems with this ARF

So far VERY disappoint with this ARF, looks geat and should be a great flyer I think…. But if you’re going to do electric no one knows where the batteries go NOT even Horizon Hobbies could figure it out. I can’t be the first one to notice this but maybe I am. The manual simply SUCKS, and does not show much of anything for the electric option. It’s a VERY POOR manual with LOTs of errors.

I spend almost 2 hours on the phone today with Horizon Hobbies product support: they also agreed that there are numerous problems with this kit & manual. Problems go like this: Just to start with

1. No instructions where the Lipo batteries go or how they are mounted/installed in the fuselage.

2. No instructions/Directions that you need to add 12-18 inches of battery leads for the ESC’s to the batteries if the batteries are mounted in the fuselage.

3. This one is REAL BS! Kit does NOT come with wheel wells tubs for the retracts in the wings, and also does not come with front nose gear doors or linkage for it, I have never seen a kti that this did not come with, usally you get that stuff and if you don’t need it you discard it, not this model! According to Horizon Hobbies you have to purchase Seagulls mechanical retract set to get the wheel tubs and nose gear doors, so if you purchased E-Flite electrics like I did you are SOL. They also don’t know how to order it apparently there’s no part number for it

Last thing that was said by Horizon was that this kit should NOT have been put out yet, and he said they he would get with a Seagull Rep and find out they had to say about it, and he said he will call me back, we will see….VERY sorry I purchased this kit!

BTW: I just called Castle ESC they said by extending the battier leads 12-18 inches would quite likely damage or destroy an ESC because of the “Ripple affect” caused by going to WOT, they said for sure you would need to add a capacitor pack to stop any “Ripple affect” thy will not warranty any castle ESC that has its battery leads extended that distance.
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Old Feb 20, 2012, 06:00 PM
Registered User
Denver, CO
Joined Apr 2009
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Quote:
Originally Posted by Craig Greening View Post
The manual is incorrect; this model does not include retracts. Mechanical retracts are an option, there are wheel wells built into the airplane.
Correct it does NOT include retracts, BUT it does NOT come with wheel well tubs installed, and least mine did not and neither did the kit Horizon product support opened today did not have them either...I think that’s complete BS that it does not come with the wells/tubs.
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Old Feb 20, 2012, 08:24 PM
William from Windham NH USA
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United States, NH, Windham
Joined Apr 2005
160 Posts
The sad thing about the seagull product line is thet offer some very interesting subjects that have not been offered!!

And get you to take the bait but miss the boat!

I was wondering if it came with the electric motor mounts and the battery boards the last three seagull models I bought came with at least that much to help with the electric conversion!

Also do not hold your breathe waiting for an answer from seagull or you will pass away.

That brings to mind that Horizion is also floating down the river for they do not take the time to pebuild one of these kits before they release it to the consumer

William
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Old Feb 20, 2012, 08:51 PM
More Motors, More Fun... :-)
nioa's Avatar
Phoenix, AZ
Joined Jan 2008
684 Posts
Sounds like I have an interesting challenge. Now I'm even more excited about receiving this airplane.

Nick
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