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Old Sep 16, 2010, 11:39 AM
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GWS P-40 Not a Build Thread Thread

As the title implies this is not a build thread as those have already been done to death. Instead, I wanted to share some tips and tricks I learned to make building the EPO version of the P-40 easier for anyone who hasn't yet built one.

The quality and fit of the parts in my kit was exceptional and everything fit like it was supposed to but there are a couple of tricks that you can do to make sure it is as straight and true as possible. I'll post some pictures that show some of these tips and also some alternatives depending on different setups.

First, glue. Do not attempt to use Foam Safe CA on EPO foam, it simply will not stick. The best glues are: Regular thin or gap filling CA, Epoxy either 5 minute or 30 minute, and GWS cement. The GWS cement doesn't bond well unless the surfaces are very clean so I use alcohol wipes to make sure the surfaces to be glued are as clean as possible. A box of 100 swabs costs about $2.00 at the drug store and they can be used to clean off excess glue as well.
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Old Sep 16, 2010, 11:52 AM
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Getting the main wing in place and straight is really important. You will need to have the wing in place to properly mount the horizontal stabilizer (elevator) so here is how to go about it.

The P-40 uses two wing screws to secure it so alignmentof these is critical. I started by cutting out the ailerons and trimming them before glueing the wing sections together. Use GWS Cement for this but be sure to spred it evenly on both sides and then wait about 5 minutes before putting them together. Press and hold them tightly making sure the tabs are aligned and the gap at the front and rear are tight and flat. Put a couple of drops of CA in several places and use accelerant to hold the wing tightly together while the GWS Cement cures. This will take about 24 hours. After it is set you can fit the fiberglass rod, servos, ailerons, and landing gear pods. More on that later.
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Old Sep 16, 2010, 12:15 PM
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OK, now that you have the main wing done it's time to align the wing retainer nuts in the fuselage. Do not glue the fuse together instead prepare each retainer nut as follows: Coat eact wing screw with petroleum jelly and screw it into the nut until it just reaches the bottom and extend it a tiny bit more. Be very careful not to get petroleum jelly on the nut. If you do, clean it thoroughly with alcohol and start over. Place the plastic nut retainer on a piece of plastic ( I used one of the wing bags ), CA will not stick to it. See photo.

Put a drop of CA ( I prefer gap filling for this) in the bottom of the nut retainer and tap the nut in with the screw in place. Hit it with some accelerant but give it a couple of minutes to thoroughly set. Next, remove the screw and run it through the nut several times to make sure it doesn't bind. Then place the screw through the left wing retainer coat it with PJ again and screw it into the retainer nut assembly. Make sure the flat side is up and put a bit of Petroleum Jelly on the face of the nut this time. Holding the wing in place align the wing seam front and back with the fuse half and with the retainer nut in place in the fuselage, put a drop of CA in either side and spritz it with accelerant. Remove the screw from the wing and screw it into the retainer nut to make sure it doesn't bind. The Petroleum Jelly should keep the CA from getting into the threads.

Repeat the process for the right half and you should have a perfectly straight wing when bolted into the saddle.
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Old Sep 16, 2010, 12:21 PM
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Next the fuselage. There are some things you should consider before gluing the fuse together. I found that I needed to make a cutout for the ESC in order to be able to connect and disconnect the motor. Since I'm using a geared inrunner I had to use the top stick. The ESC wires are routed through the bottom and you don't want to come up short or you will have to cut into your plane to connect the motor. All this must be done before gluing it together. Also notice that I glued in the motor stick. I used GWS glue for this so that If I should ever want to change to an outrunner the stick can be removed without damaging the airframe.

Also you can see in one of the photos the glue is evenly spread and beginning to get glossy indicating it is ready to join. The ESC is taped in place and the servos have also been installed.
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Old Sep 16, 2010, 01:07 PM
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Control surfaces. I like to use the Du Bro nylon hinges in these larger models for a couple of reasons. First, they are much sturdier than the plastic strips supplied by GWS with the kit. Second, they can be flush mounted to make a very close fit but still have full control movement.

I start by marking the position of each hinge and then just use my exacto knife to cut the slots. I always cut the slots a little wider to allow for some adjustment when I do the final installation. After test fitting all of the hinges and control surfaces prep the hinges by coating the center of each hinge with Petroleum Jelly but be very careful not to get any on the tabs. I use GWS glue to install the hinges and find that it works well and gives me a little time to make adjustments. The Petroleum Jelly keeps the glue from contaminating the hinge pin and also keeps any excess glue from sticking the surfaces together. When you are done they should operate very smoothly.

Notice I went a little extra on the elevator cut. Not very scale looking but I like a lot of elevator surface. In the photos you can see the close fit of all control surfaces but they are very smooth and give me almost 90 degrees of movement, way way more than enough. I'll use the transmitter to adjust the throws when I set it up.
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Old Sep 16, 2010, 01:10 PM
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Here it is all assembled and ready for painting.

More to come......
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Old Sep 17, 2010, 03:30 AM
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Hi John,

This has been a build thread actually. Thank you for sharing sound experiences with friends who have not yet biult GWS P-40.

Be reminded to thoroughly clean the surface of this EPO P-40 by the nice alcohol swabs before painting your favoured scheme on it.

Chen
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Old Sep 17, 2010, 11:26 AM
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Quote:
Originally Posted by GWS CHEN View Post
Hi John,

This has been a build thread actually. Thank you for sharing sound experiences with friends who have not yet biult GWS P-40.

Be remined to thoroughly clean the surface of this EPO P-40 by the nice alcohol swabs before painting your favoured scheme on it.

Chen
Actually I'm glad you menttioned that Chen. Many people think that paint won't stick to EPO without some special preparation. This is not true. Just thoroughly clean the surfaces before painting and it will stick just fine. I use Tamiya paints and they have worked very well on EPO.

Here is a photo of the painted P-40. It is partially finished, not all decals applied and spinner not yet installed.
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Old Sep 17, 2010, 11:42 AM
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A couple of tips on servos. I prefer GWS NARO D+ servos but I had another brand in my parts drawer so I used them. I think the GWS servos are more reliable but I saved some money by using what I already had on hand.

Before you permanently instal the aileron servos in the wing be sure to connect them to the receiver and make sure they are centered. If they are not centered when you install them you will have to cut into the wing to get the control horns off and reposition them.

Also, I used GWS glue on the servos where they contact the wing but also put a drop of epoxy on and under each tab. The last thing you want is for a servo to come loose.
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Old Sep 17, 2010, 11:56 AM
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When you paint your P-40 or other GWS EPO model make sure the surfaces are clean. Use good quality paint and if you are like me and don't have an airbrush, apply it in thin coats with spray cans. You can do a reasonable job and it doesn't matter if it looks a little different than the picture of the real ones. This is after all, your plane..

I use masking tape to keep paint out of the control bay, and out of the cockpit. I also mask off the wing servos, you don't want paint getting into the gears on a servo. I also use high tack masking tape to cover the servo wires and just paint over it. You could also cover the wing stiffener but I didn't.

Notice how neat and tidy my basement work area is. Once I get done it all gets cleaned up, my wife makes me do it..
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Old Sep 19, 2010, 11:49 AM
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OK, I'm ready for the maiden flight and will post a video as soon as I can get my son in law to break out his video camera.

Photos of the finished P-40 and the power plant are below. The motor is a GWS GWEPSQ2815RC fitted with a GWS EP-1060X3 prop. I did not put this on my test stand for fear it would break it but static testing, holding the plane at full throttle tells me that this thing will move. Using my Watts up meter I measured 411.4 watts at 36.09 amps.

Weight without the battery is 670 grams and the all up weight is 860 grams. The CG is at 45 mm back so it is about 4 1/2 ounces heavier than I expected but still OK and just slightly nose heavy. I like fast planes to be a little nose heavy anyway.

The spinner is a 2" Du Bro 3 blade. It requires some modification in that you have to Dremel the openings to fit the GWS prop and you also have to remove the three locator pins. I also fitted a proper spacer in the spinner back plate, I used one of the hundred or so APC spacers I have lying around. The spinner only comes in white or black so I got a white one and painted it red, it turned out very nice.

Notice that I have not applied any decals other than some numbers on the plane. Never put the decals on until after a couple of flights, if you break the cowel you can get another one cheap but the water slide decals are hard to find and expensive.

I want to thank Chen for all of his help in getting the motor assembly for this plane through the lonely birds program. Shipping from Tiawan was faster than I expected and as always GWS service was excellent. I think Caliber has these is stock now so if you are in the US you should be able to order one directly from them.

So that about does it. I'm going to try to fly it today and if I do I'll post video tonight. Happy flying.

John.
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Old Sep 20, 2010, 06:40 AM
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Hi John,

Thank you very much for your words and this new built thread of GWS P-40.
Good luck for the maiden !

Chen
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