Flightline RC Tigercat F7F

[Beeg]

When's the next batch of Tigercats due in? Is there going to be a V2?

[Silver Kiwi]

Watch this video of a real one starting, no counter rotating propellers.

https://youtu.be/hpph7-iunvI

Sorry, I didn't mean to suggest that the full scale aircraft had them. It's just that our model does and I think that changing the rotation on the motors would help greatly in order to keep the total thrust closer to the aircraft centerline thus lowering the Vmc and helping with directional corner at low speeds or if the motors aren't turning at the same rpm. Thanks for your input.

[dkalwishky]

The propellers should rotate toward the fuselage as this keeps the total thrust closer to the centerline of the aircraft which is critical for a twin engine airplanes as it keeps the Vmc (velocity of minimum control) lower when operating on one engine.

Watch this video of a real one starting, no counter rotating propellers.

https://youtu.be/hpph7-iunvI

[OV10]

I believe that you are correct. The propellers should rotate toward the fuselage as this keeps the total thrust closer to the centerline of the aircraft which is critical for a twin engine airplanes as it keeps the Vmc (velocity of minimum control) lower when operating on one engine. This would not be a problem for an electric powered model most of the time except when one motor doesn't produce the same RPM as the other. This is the case for my newly purchased F7F Tigercat. Grrrrr......the left motor turns 1,200 RPM slower than the right and makes it a real bear, no pun intended. Add the fact that the rotation of the motors isn't correct and it now becomes a real problem. Electric motors of equal KV should turn the same RPM with batteries of the same voltage, right! I haven't yet checked to see the Wattage output of each but as of now I have no clue for the large RPM difference. I would love to hear others comments.

Hello SK and welcome to the Squawk,
If you've got a 1200 rpm(almost 15%) difference between your two motors then their is an obvious problem(read defect) with the slower motor.
If you've had the plane less than 30 days, give Motion a call 224-633-9090 or open up a support ticket(link below) to get this problem resolved.

https://support.motionrc.net/open.php

Best regards,

[Silver Kiwi]

One thing I plan on changing is the direction of rotation of the motors, the P38 correctly rotates the props away from the fuselage, the real Tigercat rotates toward the fuselage.

I believe that you are correct. The propellers should rotate toward the fuselage as this keeps the total thrust closer to the centerline of the aircraft which is critical for a twin engine airplanes as it keeps the Vmc (velocity of minimum control) lower when operating on one engine. This would not be a problem for an electric powered model most of the time except when one motor doesn't produce the same RPM as the other. This is the case for my newly purchased F7F Tigercat. Grrrrr......the left motor turns 1,200 RPM slower than the right and makes it a real bear, no pun intended. Add the fact that the rotation of the motors isn't correct and it now becomes a real problem. Electric motors of equal KV should turn the same RPM with batteries of the same voltage, right! I haven't yet checked to see the Wattage output of each but as of now I have no clue for the large RPM difference. I would love to hear others comments.

[dkalwishky]

DK.......Actually the full size didn't have counter rotating props.

You are right, not sure what I saw that made me think the full scale plane did.

[TiredIronGRB]

Watch for this distortion around the nacelle mount, if it's like this trim it off so it will sit flush against the mount.



...I used a control rod to pull the rear servo wires through the fuse.

[OV10]

DK.......Actually the full size didn't have counter rotating props.

[dkalwishky]

One thing I plan on changing is the direction of rotation of the motors, the P38 correctly rotates the props away from the fuselage, the real Tigercat rotates toward the fuselage.

[PappaBear]

The latest offering from Flightline RC is the Grumman F7F Tigercat This new model is a similar size to the P-38 with a wingspan of 63". It is the same excellent quality we have come to expect from Flightline RC.

At this point, I would recommend you carefully check the model and make sure you are 100% satisfied with the operation of all the controls and servos before you begin the assembly. In doing that if you have a problem and you need to return the model to Motion RC you will be able to pack it in the box. Once the rear of the fuselage is glued to the front section it will no longer fit in the box.

I assembled the model in a slightly different sequence to that called for in the instruction manual. I will explain what I did and the reason for it as I go through the assembly of the model. The first thing to do is to assemble both of the propellers. These are the same style as the P-38. One is clockwise rotation and the other is anti-clockwise. They are simply held together with sheet metal screws. They go together very easily and when the decals have been applied they really do look the part.

It's at this point I deviated from the instructions. The instructions state to fit the propellers to the motors and then install the units to the wings. I didn't do this, for two reasons. First I want to make sure the motors run correctly and to be safe I don't want them fitted to the motors to carry out the tests. Also, they could get damaged while fitting the motor nacelles to the wings.

I chose to test the servos and connect all the pushrods required in the wing. These included both ailerons and four flap servos. I connected the servos to a servo tester and cycled the servos for a few minutes to makes sure they were going to be reliable. The servos should be cycled before they are connected to the control surfaces, and the control surfaces should be checked for free movement through the entire range. I intend to use a Spektrum DX8 to fly the model and a Spektrum AR8000 RX. I connected the RX to the servos and used a 4.8V battery to center all the servos. I then connected all the push rods and adjusted the control throws. I found it easier to do all this now than after the engine nacelle has been fitted to the wing.

The nacelle has to be attached to the wing next and this is simply bolted to the wing with four screws that screw into hard points installed in the wing. The wires for the retract unit and the ESC are routed down a channel in the underside of the wing. I tested the motor and the retract unit for correct operation before fitting the whole unit to the wing. When you are satisfied with the operation Both left and right wing assemblies are now ready to fit to the fuselage.

The next stage is to fit the two halves of the fuselage together. The rudder and elevator servos are located in the rear section of the fuselage and the leads have to be routed through the front half to locate in the correct position. However, before joining the two sections together I checked both servos for correct operation and again cycled them a few times to make sure they are going to be reliable. I tried a length of string to the servo leads and fed it through the front half of the fuselage before I glued the two together. This also prevents glue sticking the leads to the fuselage.

It's a good idea to fit the wings to the fuselage before gluing the fuselage together. With the wings in place on the fuselage, it is a simple job to turn the rear half of the fuselage left or right to align the wings and the horizontal stabilizer together before the glues sets. This will make for a perfectly straight model. The horizontal stabilizer fits to the fuselage on a carbon fiber tube and it is secured to the fuselage with four small screws, two on each side. I fitted my RX inside the fuselage close to the main control board, and the satellite RX ahead of the main one. I used double sided sticky pads for both.

The decals are fairly easy to apply. Three different color combinations are supplied with the decals. This model does not include a lot of small decals that require a lot of time and attention to fit.

All that is left to do now is to balance the model and go and fly. The two batteries are located in the front of the fuselage, one behind the other.

The first take off and landing was really a non event. I was really very surprised at how well this model flew right off. I did not use flaps for the take off or landing. I can say the model flies really well and I would recommend it to anyone who is looking for something a little different. As you can see from the photos above the model does look very realistic in the air.

Martin.