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Community Build F/A-18 Super Hornet 2B the FT-18 when completed

HilldaFlyer

Active member
#1
Hello all FT Scratch Builders.

I would like to start this thread to complete a community build of the F/A-18 Super Hornet. There are lots of foamy designs out there, but I would like to have one for FT.
FT-18 Article Icon-01s.jpg

The goals of this build will be
  1. Use simple build designs familiar to FT for beginner builders.
  2. Have the same wingspan as the FT-22 (26")

I've done a lot of leg work to get this project started, so I'll just start by showing what I've done.

First, I've collected photos from the internet, and some really great profile layouts to form the basis for the general plane's shape. I'm pretty good with the computer, but it is still easier for me to print out something and draw on it to get the general idea of what parts are needed for a FT aircraft.

IMG_1879s.jpg

Here are some thoughts after drawing my proposed outlines:
The fuselage isn’t as wide as the prop hole needs to be - note that in the FT-22 the fuselage is way wider than “scale”. This may be why a lot of park jet plans have the motor hanging off the rear of the plane? Make the rear fuselage same width as the leading edge wing extensions to add strength to tail. I would like to allow for 7” propeller, the same power train that is on the FT-22.

The prop hole cuts a huge section out of the wing. We may need to add wing support like KF airfoils or CF rods (fly without to see). RCPowers always uses carbon tubes in his designs because Depron is not stiff enough on its own to support the forces of flight.

We'll have to see if a single layer of foam core is strong enough. If not, we'll have to use either KF airfoils which will double the wing thickness on LE or add carbon fiber tube by cutting open and hot glue rod in one thickness to keep weight down. Tape over cut. We will have to build one and see if carbon is needed.

My calculations from the sketch indicates we’ll need a 7” propeller to power the plane and an about an 8 inch propeller hole. This is for the same motor/prop as I have with the FT-22. If we use the outside of the fuselage as the outer limit of the hole, then I calculated that the wingspan would be 52” which is exactly twice the FT-22 at 26”. To get a plane down to 26” wingspan, we will need to widen the fuselage with respect to the wings, just like the FT-22.

If I alter the plans so that a 8" prop hole aligns with the point where the leading edge wing extensions meets the wing, then the wingspan needs to be 26.25” rather than 52”, only 0.25” longer than FT-22. This is doable.

The tail is skinnier than the leading edge wing extensions, so the fuselage under the wing will have to taper down or the tail will have to be wider.

With these thoughts, I dropped the image into Adobe Illustrator and traced out the parts that I would need. It was a lot easier than I anticipated. In one evening I had printable plans (of some sort)

It only took an hour to print, tape and cut out the 26 inch plane and it seems like it will work well without additional structural support on the wings...

IMG_1796s.jpg

This roughed out model does not have any contouring on the fuselage, I did it to see if the wings and fuselage would mesh and to see how the fuselage under the wing would work.

IMG_1798s.jpg

You can probably tell that I designed the under-wing fuselage to be shaped hourglass-like. I was also trying to get the engine intakes to be angled. After cutting it out several time I succeeded, as you can tell, but it was very complicated. I decided that to keep it simple for the FT beginners, we would need to come up with a "straight" design. We can put this design into the next more advanced build. The tapered fuselage would trap a lot of thrust right behind the prop with the skid plate in place. This is the main reason for changing to a straight design

I wanted to see if I put the propeller hole in the right spot, so I laid the electronics on the plane and held them in place with a little tape.

IMG_1797s.jpg

WOW! That make me happy! :) Looks like it will balance with the motor and propeller in the forward part of the wing.

I altered the plans to make a two piece rear fuselage, one that extends from the point where the wing meets the leading edge wing extensions to the wing's trailing edge, and the other the same width as the tail that extends from the propeller slot to the tail.

IMG_1804s.jpg

Here is the inside fuselage pieces that extend from the tail to the propeller hole. The outside fuselage sides I decided to combine with the belly plate for added strength and support.

IMG_1802s.jpg

The belly plat has tabs that mount inside the propeller hole, so it looks like this when attached.

IMG_1856s.jpg

The prop hole doesn't have to be as wide on the belly plate, so I just cut it out to what I thought was a nice size.

The rest of the electronics were installed.

IMG_1808s.jpg

To mount the servos... I used little "nests". I know the Readi-Board peels really easily, so a little torquing and the paper lifts off the foam. This provides added stability to the servos.

IMG_1809s.jpg

The receiver is mounted in the rear, this way only one wire is snaked past that wire chopper called the propeller. The ESC is mounted in the body below the wing and the battery directly above the ESC. I had to use a 15 cm servo extension on the ESC to get it to reach the receiver.

IMG_1812s.jpg

I forgot to mention that the new design has a cockpit window bubble and a pointed fuselage. It is a little more advanced than simple, but it can be done.

IMG_1810s.jpg

Prototype #1 complete... This has a HK D2822 1450kv motor with a 7x6 propeller.
 
#6
F-18 v2

I've already decided to upgrade or create a version 2.
I read a recent article that demonstrated a plane made with Ross foam core withstood getting wet, actually it crashed into a lake! I decided to build another F-18 with Ross as the construction material.

I made a stop motion video of the build which took 2 hours...

[video]https://youtu.be/FZkDfzBHPpM[/video]

The REAL upgrade was I put a 2200kv motor on it with a 6x4 propeller.

IMG_1860s.jpg

With a 6" propeller, the propeller hole can be 2 cm narrower.

Here it is ---

F-18 v2.jpg

And it really does... well kinda'

I trimmed it out and was having a great time when the motor cut out as I pushed the throttle all the way to the wall.

[video]https://youtu.be/FCVWYPj_nic[/video]

Turns out the ESC fried. Grayson Hobby ESC rated at 30A. I checked the configuration and this motor combo doesn't suck more than 28A, so I guess it was a faulty ESC or it got some moisture in it. Here is the damage>
IMG_1888s.jpg

I replaced it with a Turnigy Plush 30A ESC to see if it will hang in there. We'll have to wait and see. In the mean time, I put the Ross foam board to the real test - airbrush paint!

Paintings.jpg

Now I really want to fly it again.
When I painted it, the stress marks on the wings became visible. There are small creases that run from the propeller hole to the tail. I'll bet the wings will fold at some point. Version 3 will include the option of installing a carbon tube in the wing. Flat foam core just doesn't have the strength to support this type of aircraft.
 
#8
Not looking to steal the thread but Just finished this Ross foam board up yesterday, the front is the FT- f22 and the back half is an Avro arrow. A bit under powered with a blue wonder and 800 mah but it flies fine.

virtually unstallable, nose just comes right back down, and it floats in like a helium balloon. I think I am going to add a rudder servo and see how that does.

ATT_1444557888606_20151011_060310_HDR-crop.jpg
 
#9
Not looking to steal the thread but Just finished this Ross foam board up yesterday, the front is the FT- f22 and the back half is an Avro arrow. A bit under powered with a blue wonder and 800 mah but it flies fine.

virtually unstallable, nose just comes right back down, and it floats in like a helium balloon. I think I am going to add a rudder servo and see how that does.

View attachment 55843
That's cool looking. When is the article coming? Love to see it.
 
#10
This past week I put the finishing touches on version 3. Added a 3 mm carbon fiber tube to the wing to keep it from flapping in the breeze.
IMG_1927bcs.jpg

Plans and article are in queue.
 
#11
F18 super Hornet

Thanks for posting the plans and article they were great and easy to follow. Ready for it's maiden, I'm running a blue wonder with a 800 mah.



20151029_161417_HDR-crop.jpg
 
#12
Maiden flight went exceptionally well! just a few clicks of trim and she was flying straight and true.

I did build it out of ross board but did not put a spar in the wing. Only using the blue wonder and don't plan on any extreme flying.

I was surprised on how well it did slow down for landing, floated right in.

Thanks again
 
#13
Maiden flight went exceptionally well! just a few clicks of trim and she was flying straight and true.

I did build it out of ross board but did not put a spar in the wing. Only using the blue wonder and don't plan on any extreme flying.

I was surprised on how well it did slow down for landing, floated right in.

Thanks again
Yeah!
Looks awesome! Great job :) Glad to hear it went well. I think the build is really easy too - ready for new FT line called Instabuild.
 
#14
I built one at 80% last night to use a multi-rotor sized motor. No paint yet. Too windy today for maiden. Surprised I had trouble being nose heavy, usually its the other way around.
 
#16
Crashed the F-18 v3

Do you like crash stories???

I went flying last weekend and had a great time. The following was my fifth flight with the F-18 v3... a red-tailed hawk joined me in the air. I went for a high speed loop and turfed it.

Here is a video of the whole thing

Here is the damage:



10 minutes later with a hot glue gun...


almost as good as new! Still flies great!
Ross foam board is awesome stuff. Paper held on... it was great.
 

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#17
Trying to Crash the F-18 v1

The first F-18 made of Readi-Board had warped wings from the very first flight. After landing in the dew, the skid plate peeled.



So I flew it four times trying to get the wings to fold. They didn't, but the last two flights were simply fun.
I guess if you bend the wings on purpose, you can get a really good indoor flyer. Watch this....

[video]https://youtu.be/-TPVfi51v5o[/video]
 
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#18
I also like the Ross board much better, I went to my local Walmart and asked the dept. manager to order me 2 cases.

Hopefully they should be arriving within a week.
 
#19
I maiden the 80% ( 21" wingspan, length 29" ) with 1804 motor, 3s 500mah, 5X4 prop. Total flying weight was 195grams. I was hoping mini power pod would fit but not quite so I glued it in. Seemed fast enough going straight but just not quite enough thrust, barely had some vertical and rolls weren't near as tight as I wanted. Will adjust to the outer most hole on servo and see if I can get more throw and will do a 6X3 prop and see it that gets me a little more thrust. If not will have to build at 70% and see if can get to perform with my existing 1804. I have a 2204 motor that would have no trouble with vertical but really want to try to make 1804 work.

I did manage to hit a tree on the second battery, luckily didn't get stuck just a crumpled nose and few bites out of the wing.


No decorations still just foam board until it flys well enough. Easy enough to build likely will wait until next one to add color.

Pictures with the 6X3 already installed. Just the right length slot for it.

 
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