GWS F-15 Build Thread

[Jarron]

Back in 2019, I was tasked to build not one, but two of our GWS F-15s. Here's how it went. If you're thinking about buying one of these fun to fly, surprise free airplanes, go ahead and look through this build thread.

First I'll list the equipment I recommend using:
ESCs x2: https://alofthobbies.com/hobbywing-flyfun-mini-30a-esc-v5.html
Battery: https://alofthobbies.com/gens-adventure-2200-11-1v-50c.html
Servos x5: https://alofthobbies.com/power-hd-hd-1900a.html
Glue: https://alofthobbies.com/foam-cure.html
Wire for motor lead extensions 16AWG for battery leads, 18AWG for motor lead extensions: https://alofthobbies.com/silicone-insulated-power-wire.html

After balancing the included 6 blade, 64mm EDF units, (more info on this in a future thread) I placed them in their mounting spaces in the upper half of the fuselages. I already had a set of two 30 amp ESCs lying around, so after setting them up for twin motors, I placed them in their respective compartment up at the front. This is so I could measure how long I needed to make the motor extension leads:

I decided to not use bullet connectors in this build, as you won't really be able to get to them easily anyways once you button up the fuselage. So I clipped off the weird GWS bullet connector thingies from the leads coming from the motors, then stripped them back a few millimeters. Then I cut, tinned and soldered on six 18AWG extension leads, being absolutely sure that motor rotation was correct:

I placed a dollop of our Foam Cure glue under each fan and rotated the units back and forth in their mounts to spread out the glue. Now it's time to get to work on installing the included adjustable pushrod connectors to each of your five servo arms. Look at this diagram, it explains the installation:

Got it? Okay let's go.
I drilled out the second hold from the outermost hole on all of my single output servo arms to 2.1mm:

Then I pressed the pushrod connector body through the hole like this. It should be a tight fit, but with almost no play:

Then grab one of these little red plastic fiber washers and install it like so:

A plastic bushing pressed over the shaft locks it all together:

Now, repeat this process four more times. Once done, grab the bottom half of your fuselage. See the block of foam I'm pointing at with my razor knife?

It called your mother ugly, so you need to cut it out, like this. Use a fresh blade:

There's another one on the other side too, so cut that one too.

 

[Jarron]

More on this tomorrow.

 

[Jarron]

Ha ha, I lied. Anyways, on with the build.

I grabbed two of my servos and installed servo arms on them, making sure to center them and that the arms were facing in opposite directions and as close to 90 degrees as possible. These will be used as the elevator servos. Now the servos I used have too long of a lead, so I cut them short enough so that when I installed the new plug on the end, it rests neatly in this channel. You'll want the servo arms to be facing down like I have here:

Before connecting and routing the included servo lead extensions, I took the time to install the wing hardpoints, those are the black thingies under the servo wires:

And here is the finished wiring. I used drops of foam safe CA to tack down the servo leads:

After being sure that i had everything working properly, I glued the upper and lower fuselage halves together and I also cut out and installed the cheater hole covers, they cover the gaping holes in the top of the fuselage that used to be needed in the old days before brushless motors:

Next are the vertical fins and their mounts, the fins are held in their mounts by two bolts per fin, so they can be removed for storage/transport:

That's all for today, stay tuned for more of this build tomorrow!

 

[Jarron]

Time to build the landing gear!
I went and harvested the main landing gear mounts as well as the parts for the nose gear from the included black parts tree, then assembled them as per the manual:

Left and right main gear (minus wheels..for now)

Nose gear:

Spacers made from plastic tubing keep the wheels from rubbing against the wire struts:

Make sure that the main gear has the coily bit facing the rear of the plane:

And that the axles face outwards:

All landing gear installed! Now to install the nose gear steering servo and it's onto the horizontal tails.

 

[Jarron]

Installation of the nose gear steering servo was easy, just glue the servo into the pocket and pass the lead up into the receiver compartment. Then attach the included linkage like so. Don't forget to center the servo and nose gear before tightening the linkage stopper.

I started by gluing in the included fiberglass tubes into the horizontal stabilizers, then cut out the elevators with a fresh razor blade for a cleaner cut.

Then I slotted both the elevators and stabilizers to accept my hinges of choice. Once everything was cured..

I glued them to the fuselage.

The next day, I installed the elevator control horns and connected the linkages. However the L bends I made in the music wire the kit supplied made them too short!

Good thing I had already stopped at a certain hobby shop that sold K&S and grabbed some bundles of 1.4mm music wire, the same stuff used in the kit! I didn't waste time cutting new lengths. Excess wire was snipped off.

 

[simon]

Thanks for all the detailed photos. We’re using this log to help us build ours today.

 

[ThatGunGuy93]

I have a question. I ordered this from y'all and it'll arrive tomorrow I have a question about the battery recommendation, most twin 64mm edf's run off 6s lipos, so how does this plane only need a 3s? Would 4s be ok with a twin 40A ESC?

Sent from my SM-S911U using Tapatalk

 

[Wayne]

The voltage requirement will be tied directly to the specs of the motor and the fan blades. If you tried 6S on this motor you would have a major meltdown.

I'll let @Jarron answer the 4S question as I do not know. He is the master of this model.

 

[Chris]

My fans blew out eventually on 4S. The aircraft is so light it is not needed to go bigger than spec.

 

[Jarron]

I have a question. I ordered this from y'all and it'll arrive tomorrow I have a question about the battery recommendation, most twin 64mm edf's run off 6s lipos, so how does this plane only need a 3s? Would 4s be ok with a twin 40A ESC?

Sent from my SM-S911U using Tapatalk

Hello! This is a very light jet and from the mid 2000s when EDFs were just starting to get good. These do not require a ton of power to fly with the lightweight and fairly efficient power system these come with (when balanced, these are actually one of the best economy 64mm fans out there, I used to buy them ten at a time for various projects LOL). The airframe is a bit draggy and it flies a lot like a trainer, so not best for going super fast but if you want some more oomph, grab a pair of these guys and run your 40A ESCs of choice. https://www.motionrc.com/products/f...edf-4s-power-system-w-2836-3300kv-motor-e7204 You'll find that they won't fit properly, so you'll need to sand the foam where the fans go. Power them with a 4s 2200-3300mAh, flight times will go down a bit due to extra amperage, but that is the tradeoff.

 

[jure]

another option is to convert it to a pusher prop.
it is much more efficient and even lighter, as smaller batteries will be enough , instead of the ones required for the EDF configuration.

but , if you like to stay faithful to the original design of record , and also like the sound of a flying vacuum cleaner, go with the EDFs

 

[Jarron]

another option is to convert it to a pusher prop.

Gross LOL

 

[jure]

here is my example :

PS#1 : my specs:
AUW is 948 g or 33.44 oz. ( no landing gear )
4 x 9 g servos
Motor from the Freewing Moray : size 3040 , Kv = 1400 RPM / V , weight = 114 gram
Battery : 3S 2200 mAh LiPo
propeller 8*8 APC
Static current is 25A @ full throttle.

PS#2 :
the performance shown in the video is not achievable with the stock EDFs and battery

 

[Wayne]

My take - the stock motors are fine. Balance them and you will have a good setup.

This model really does not change much even when people double the power. It is never going to be fast, but it will do a lot of things that the fast ones can not do.

It is great bang for the buck!! That is for sure.

 

[ThatGunGuy93]

Oh well thank you I'll keep what it comes with then sine I have a bunch of 2200mah 3s batteries lol

Sent from my SM-S911U using Tapatalk

 

[Jarron]

Oh well thank you I'll keep what it comes with then sine I have a bunch of 2200mah 3s batteries lol

Sent from my SM-S911U using Tapatalk

If you'd like, you can send the fans in to us, I'll balance them for you for $30. PM me for payment info/address and stuff

 

[ThatGunGuy93]

If you'd like, you can send the fans in to us, I'll balance them for you for $30. PM me for payment info/address and stuff

I can do that, but thank you. However you wouldn't happen to know how to make the EPS foam this jet is made out of more durable and less fragile/brittle? I don't have a RC runway anywhere locally and I have always belly landed all my RC planes/jets, however the foam this is made from feels like it's going to break when I belly land, even with my near perfect belly landing skills and the flat all grass section of my yard I do my landings in.

Sent from my SM-S911U using Tapatalk

 

[Wayne]

If you have grass to touch down in you will probably be OK. She is pretty good at spot landings. But a little packing tape on the bottom would go a long way!

The foam is both the blessing and the curse. It is lightweight, but not very durable.

Oh yeah, I suggest you skip the full flying elevator option they show in the instructions. Go with the normal elevator setup. Works much better!

 

[ThatGunGuy93]

If you have grass to touch down in you will probably be OK. She is pretty good at spot landings. But a little packing tape on the bottom would go a long way!

The foam is both the blessing and the curse. It is lightweight, but not very durable.

Oh yeah, I suggest you skip the full flying elevator option they show in the instructions. Go with the normal elevator setup. Works much better!

Much appreciated advice. She'll probably be taking her maiden flight this Wednesday

Sent from my SM-S911U using Tapatalk

 

[Jarron]

Much appreciated advice. She'll probably be taking her maiden flight this Wednesday

Sent from my SM-S911U using Tapatalk

@RafaelAvila and I repaired an E flite Night Radian fuselage section by filling in with depron foam and sanding to shape. I had the idea to smear a coating of BSI Foam Cure to toughen it, which worked well. You could do this to the belly of your F-15.