Official Freewing F/A-18C Hornet 90mm EDF Thread

[Scottchman]

17 flights now on mine and I can't get it dialed in the way I like, still have some strange issues when I drop the flaps, seems to get unstable at that moment, checked all the hinges, linkages, horns and all that, other than that is flies good, take offs are straight as an arrow, I really like that and the climb out is great with the 1835kv unit, flares nicely and I think this is the only jet that I am able to wheelie so they must have got the landing gear in the perfect spot, can't say I love flying it but I can say, I love looking at it, wow what a beauty, just hoping I can get it dialed in the way I want. Waiting on my servo tester to get here so I can test all my servos to see if I have a problem with one, anyone else weigh theirs? mine is a little over 6 lbs , no battery.

My non-Blue Angles version weighs 7.08 Lbs. with Gens 5000mah 6s. nothing else on board other than receiver plus stock items.

[Dustman]

Tiredlron GRB where did you get the cockpit from? Radar-Guy for some reason I can't down load the file for the hub cap covers. I get a message about the certificate not being trusted.

[janmb]

Well I tried a different mix to get the wobble out of mine when doing axial aileron/ taileron rolls. I had rudder mixed in and wasn't real happy. Looking at it the elevators seem to have a lot of up compared to the center line and the tail was dropping in the roll so I added a down elevator mix to the tailerons. It worked! 8% was the sweet spot.

Huge disclaimer here, since I don't yet have the model, but here is my take. These are also general observations and nothing to do with you in particular.

If down elevator mix helps, this strongly indicates a nose heavy setup, and a better cure for the observed behavior is most likely to get the cg tuned properly first.

Keep in mind that a correct cg is not just defined by "it feels ok", "tracks like an arrow", or "worked fine for me".

If looking for clean axial rolls when rolling fast, a really good cg is the first and most important step.


On a jet like the F-18, I will be looking for a cg the is very close to hands off inverted flight. Close, but not quite, as in the tiniest amount of elevator push needed at middle throttle settings. This does however require the ability to fly coordinated, low bank rudder turns. Bank and yank at slow speeds will at best look bad, and worst case see you spiral down. Which is exactly how things ought to be 🤡


Get this right, and the need for mixes will most likely be gone.

[Evan D]

Cool. When you get yours flying and program in tailerons tell me where your balance is and if it rolls straight.

I have mine balanced about 4-5mm behind the book value and it seems most other pilots are happy with the books value. I think the balance is as good as it will get even though it does need a little push inverted. Going back any more it starts to loose directional stability (like a dart missing feathers).

If anything I think the wing incidence and flap and aileron center positions are affecting it more. At the book value for up flaps and centering the ailerons to the flaps it looks like a lot of wing incidence. Then if you look at the apparent stab incidence there is a big difference. I might at some point raise the flaps (not sure how much I can before it hits the stops) and ailerons to match and see what that does. There will probably always be idiosyncrasies as this is a "scale" EDF and not a neutral pattern plane.

That said it flies well at the book CG, book flap/ aileron/ stab positions. But let us know what you find when you fly yours.

Huge disclaimer here, since I don't yet have the model, but here is my take. These are also general observations and nothing to do with you in particular.

If down elevator mix helps, this strongly indicates a nose heavy setup, and a better cure for the observed behavior is most likely to get the cg tuned properly first.

Keep in mind that a correct cg is not just defined by "it feels ok", "tracks like an arrow", or "worked fine for me".

If looking for clean axial rolls when rolling fast, a really good cg is the first and most important step.


On a jet like the F-18, I will be looking for a cg the is very close to hands off inverted flight. Close, but not quite, as in the tiniest amount of elevator push needed at middle throttle settings. This does however require the ability to fly coordinated, low bank rudder turns. Bank and yank at slow speeds will at best look bad, and worst case see you spiral down. Which is exactly how things ought to be 🤡


Get this right, and the need for mixes will most likely be gone.

[DCORSAIR]

Huge disclaimer here, since I don't yet have the model, but here is my take. These are also general observations and nothing to do with you in particular.

If down elevator mix helps, this strongly indicates a nose heavy setup, and a better cure for the observed behavior is most likely to get the cg tuned properly first.

Keep in mind that a correct cg is not just defined by "it feels ok", "tracks like an arrow", or "worked fine for me".

If looking for clean axial rolls when rolling fast, a really good cg is the first and most important step.


On a jet like the F-18, I will be looking for a cg the is very close to hands off inverted flight. Close, but not quite, as in the tiniest amount of elevator push needed at middle throttle settings. This does however require the ability to fly coordinated, low bank rudder turns. Bank and yank at slow speeds will at best look bad, and worst case see you spiral down. Which is exactly how things ought to be 🤡


Get this right, and the need for mixes will most likely be gone.

When you get yours, you tell us all about it and move that CG as far back as you like it.......:)

Of course you will get one of the gremlin free ones and it flies perfect.LOL

[xviper]

On a jet like the F-18, I will be looking for a cg the is very close to hands off inverted flight.

This statement has me a little confused. How is the F-18 wing any different than most any other airplane wings ................................ ie, isn't it curved on top and flat-ish on the bottom? This is to make lift (lower pressure on top than on the bottom). If you invert, doesn't that lift become reversed and pull the plane down, thereby requiring some "down" elevator? If you adjust the CG such that it's so far back to fly "hands off" inverted, wouldn't that require quite a bit of "down" elevator to fly level right side up? :Confused:

3D stunt planes can do it but they have nearly symmetrical wing cross section.

[fhhuber]

This statement has me a little confused. How is the F-18 wing any different than most any other airplane wings ................................ ie, isn't it curved on top and flat-ish on the bottom? This is to make lift (lower pressure on top than on the bottom). If you invert, doesn't that lift become reversed and pull the plane down, thereby requiring some "down" elevator? If you adjust the CG such that it's so far back to fly "hands off" inverted, wouldn't that require quite a bit of "down" elevator to fly level right side up? :Confused:

3D stunt planes can do it but they have nearly symmetrical wing cross section.

Hands off both upright and inverted is not really a function of airfoil or wing plan-form. Its mostly a near aft limit CG with "0-0-0" thrust line, wing incidence and horizontal stab incidence in relation to each other.

You can get there more easily with a flying stab model such as the F14, F-4 Phantom and the F18 due to just needing to adjust thrust line to the wing (or wing to the thrust line), then trim the horizontal stab trim.

I revised a Goldberg Tiger 60 to fly hands off upright and inverted. You can do it with a Kadet Senior. You have to shim the wings and tail surfaces and adjust the thrust line.

We expect the jets to be flown inverted more than you'd fly the Kadet inverted. Also the aft CG require more pilot skill for getting out of spins, s the trainers tend to have the CG forward, incidence on the wing, - incidence on the tail and "down-thrust to deal" with the wing being high resulting in the plane wanting to nose up with added power if you do not give it a negative thrust angle.

There's a video on youtube (very old so hard to find) of someone doing 3D with an Avistar trainer. They adjusted CG, incidences, trims and selected the right prop

[janmb]

Cool. When you get yours flying and program in tailerons tell me where your balance is and if it rolls straight.

I have mine balanced about 4-5mm behind the book value and it seems most other pilots are happy with the books value. I think the balance is as good as it will get even though it does need a little push inverted. Going back any more it starts to loose directional stability (like a dart missing feathers).

If anything I think the wing incidence and flap and aileron center positions are affecting it more. At the book value for up flaps and centering the ailerons to the flaps it looks like a lot of wing incidence. Then if you look at the apparent stab incidence there is a big difference. I might at some point raise the flaps (not sure how much I can before it hits the stops) and ailerons to match and see what that does. There will probably always be idiosyncrasies as this is a "scale" EDF and not a neutral pattern plane.

That said it flies well at the book CG, book flap/ aileron/ stab positions. But let us know what you find when you fly yours.

Agreed. And I will. Just need to get the darn thing first - seems it's still 1+ months into the future for me.

When you get yours, you tell us all about it and move that CG as far back as you like it.......:)

Of course you will get one of the gremlin free ones and it flies perfect.LOL

I certainly will.

As for gremlins, in my case I won't really have anything but myself to blame, since the only stock electronics I will have are the retracts. (ARF+ version with JetFan/HET 8S combo, hobbywing ESC, CC pro 20A BEC, Hitec servos all around, jeti rx, no BB)

This statement has me a little confused. How is the F-18 wing any different than most any other airplane wings ................................ ie, isn't it curved on top and flat-ish on the bottom? This is to make lift (lower pressure on top than on the bottom). If you invert, doesn't that lift become reversed and pull the plane down, thereby requiring some "down" elevator? If you adjust the CG such that it's so far back to fly "hands off" inverted, wouldn't that require quite a bit of "down" elevator to fly level right side up? :Confused:

3D stunt planes can do it but they have nearly symmetrical wing cross section.

See the response from fhhuber - he beat me to it and explained it very well.

[duke]

OK guys I'm going to maiden mine tomorrow. Do I use the set up in the manual or what are the recommendations?
I will be flying with 6s and up graded fan.
Thanks for the input/recommendations.
Duke 2275

[Evan D]

Book set up works well.

[fredmdbud]

This statement has me a little confused. How is the F-18 wing any different than most any other airplane wings ................................ ie, isn't it curved on top and flat-ish on the bottom? This is to make lift (lower pressure on top than on the bottom). If you invert, doesn't that lift become reversed and pull the plane down, thereby requiring some "down" elevator? If you adjust the CG such that it's so far back to fly "hands off" inverted, wouldn't that require quite a bit of "down" elevator to fly level right side up? :Confused:

3D stunt planes can do it but they have nearly symmetrical wing cross section.

Here are some interesting articles:

https://www.flyingmag.com/pilots-places/pilots-adventures-more/truth-about-wing-incidence/

https://www.boldmethod.com/learn-to-fly/aircraft-systems/wing-washout-how-it-makes-your-airplane-more-stable/

Go to "How Much Washout Is Built In?", it uses the F/A-18 as an example.

[Evan D]

:Angry:Sometimes I just want to close this site.

[fredmdbud]

:Angry:Sometimes I just want to close this site.

What brought that out

[Aros]

OK guys I'm going to maiden mine tomorrow. Do I use the set up in the manual or what are the recommendations? I will be flying with 6s and up graded fan. Thanks for the input/recommendations.

Well Duke, good luck and Happy Landings on the maiden! As some like Evan will tell you, they say the book recommendations are a good place to start. For me personally, I found the aileron recommended low rates still way too twitchy for my tastes. I have dialed mine back to about 70% and it feels much better there. Now granted, we all have our preferences but for me personally, I like to limit my roll authority on a jet when I am maidening and getting to know it. Most tend to agree on the CG while some are 5mm (+/-), but the recommended seems to be a good starting point. Be sure to to do a thorough job checking all control surface authority, CG, range check, be sure there are no "gremlins" lurking (servos acting strangely in different configurations/power settings, etc) that you can see, basically all the usual things you would want to do before a flight and especially a maiden. Again, good luck and let us know how it goes!

[janmb]

Well Duke, good luck and Happy Landings on the maiden! As some like Evan will tell you, they say the book recommendations are a good place to start. For me personally, I found the aileron recommended low rates still way too twitchy for my tastes. I have dialed mine back to about 70% and it feels much better there. Now granted, we all have our preferences but for me personally, I like to limit my roll authority on a jet when I am maidening and getting to know it. Most tend to agree on the CG while some are 5mm (+/-), but the recommended seems to be a good starting point. Be sure to to do a thorough job checking all control surface authority, CG, range check, be sure there are no "gremlins" lurking (servos acting strangely in different configurations/power settings, etc) that you can see, basically all the usual things you would want to do before a flight and especially a maiden. Again, good luck and let us know how it goes!

+1.

Book CG is always a sensible starting point, regardless of whether or not you end up tuning it.

As for rates, I completely agree. For some reason, freewing seems very very liberal with their recommendations - I find manual rates (even low) far too much for most models.

[Jetguy]

We still waiting, for the plane.

[Drifty]

Maiden`d mine yesterday. All went well, used stock settings, flew and landed without a hitch. Bypassed the BB right from the start.

[thisguy65]

More frustration. Bypassed blue box because of elevator twitching. Past post i said rudder, this was wrong. Bypassing solved it.

RX, is a lemon w/ sat. Sat was not hooked up but the radio was beside the plane. Plane function correctly for a week. A week ago from today, Friday, day before I was going to maiden it, it’s like everything went to hell in a hand basket. Nose retract went out the night before and I decided to order new elevator servo. One was only twitching but went a head and replaced both of them, to be safe

As I was working on the elevator, saw the right wing flap randomly move/twitch. Extension are good, hook a voltmeter up to read resistance. Servo is not hot. It’s completely random in how much the servo moves, when the servo moves.

When first put the plane together each servo was tested on a servo tester for 10 minutes using a old esc and 3s battery

elevator twitching an flap are two totally different, types. I would call elevator to be more of a fluttering

I’m about at my wits end. Was getting getting late and called it a night.

Rx has been swapped from two other brands, same thing.

Ever see Old Yeller, at the end? It’s getting to that point.

think I have extra 9 gram servo, I’ll swap out

[DCORSAIR]

Well two more flights this morning before work, I have to say, I finally got it dialed in nicely, landings are a thing of beauty, slows down nicely for a flare onto the mains, I keep backing off the flaps and now I'm at around 38mm, little bit of up mix with the elevator mixed in with full flaps, keeps the nose up just a bit for the approach and is very stable, little blip of the throttle every now and then makes for a nice steady approach, hope to get more flights in this weekend, maybe a video, now I need the gray one with the drop tanks and missles.....:Cool:

[Woodcock]

More frustration. Bypassed blue box because of elevator twitching. Past post i said rudder, this was wrong. Bypassing solved it.

RX, is a lemon w/ sat. Sat was not hooked up but the radio was beside the plane. Plane function correctly for a week. A week ago from today, Friday, day before I was going to maiden it, it’s like everything went to hell in a hand basket. Nose retract went out the night before and I decided to order new elevator servo. One was only twitching but went a head and replaced both of them, to be safe

As I was working on the elevator, saw the right wing flap randomly move/twitch. Extension are good, hook a voltmeter up to read resistance. Servo is not hot. It’s completely random in how much the servo moves, when the servo moves.

When first put the plane together each servo was tested on a servo tester for 10 minutes using a old esc and 3s battery

elevator twitching an flap are two totally different, types. I would call elevator to be more of a fluttering

I’m about at my wits end. Was getting getting late and called it a night.

Rx has been swapped from two other brands, same thing.

Ever see Old Yeller, at the end? It’s getting to that point.

think I have extra 9 gram servo, I’ll swap out

Man! I feel for ya mate. That's the point where I completely undo everything and start over one step at a time. Good luck man!

W