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

[Airguardian]

Some more Hornet flying :)
(We need to decrease shutter speed to get rid of the light flickering, I know!)

[nuts-n-volts]

Evan and LB, all the work you guys do is impressive! Thanks for all the great info and files.

[ColtPilot]

Aros and Airguardian , the 3D cockpit is outstanding. I also put a 1/10 scale JHH pilot in as well. It's certainly worth the effort, but the only concern was that the 3D cockpit and pilot added another 150 g (over 5 ounces) of weight to the nose. I now place my RT 6250 as far back as possible (even removed the circuit board for extra room) and the furthest back I can get my CG is 98mm, and that's already with another 1.5 ounces of lead in the elevator bays. It also has the RC Geek twin AB's in for a little more tail weight, but to even get close to the 112 mm Airguardian is flying, it would require more lead, something I'm not too keen on adding or a lighter weight battery-but love the 5-6 minute flight time. With all the extras and the paint and graphics, it came in at over 1.2 pounds heavier than the stock grey, but that extra weight seems to hardly be noticed. I've flown it as far forward as 92mm, and it flies great, but like it even more further back. Can't imagine what it would handle like at 112 mm, and I do have a gyro in it. Keep up the outstanding video's!!

I'd like to have that cockpit in my Blue Angels B1RD.

[Madness]

Hi everyone! I have s situation with my F18 that I would like your comments about it. I have tried to fly the airplane on 4 different occasions but the plane just doesn't wants to take off. My plane is the stock grey version. On Maiden the plane crashed at take off because the motor cables somehow got disconnected from the ESC in mid air and it went down. I replaced the fuselage and extended the ESC cables. After that, the plane just don't rotate at take off. It has the speed on the runway (asphalt) and the elevator fully deployed (and flaps) and it just don't take off. After 3 attempts I'm about to throw the plane to the garbage. I have checked and rechecked throws, CG, gyro, EDF...everything according to manual and nothing. Are there more cases like these on this or any other models? Today was the 3rd crash trying to take off!!!! 😡 I have no problems with my other 4 planes (two 70mm, 1 80mm and a Freewing F-16 90mm) I'm curious because all this happened after I changed the fuselage. On the very first flight at least the plane was on the air, now it just won't take off!!! 🤬🤬

Thanks in advance for your feedback.

[Evan D]

If you can post pics do a pic of neutral elevator and full elevator. Also a picture of where yours is balancing at.

[Madness]

Here are the photos of the battery on it's CG position and the elevator at neutral.

[Hugh Wiedman]

Hi everyone! I have s situation with my F18 that I would like your comments about it. I have tried to fly the airplane on 4 different occasions but the plane just doesn't wants to take off. My plane is the stock grey version. On Maiden the plane crashed at take off because the motor cables somehow got disconnected from the ESC in mid air and it went down. I replaced the fuselage and extended the ESC cables. After that, the plane just don't rotate at take off. It has the speed on the runway (asphalt) and the elevator fully deployed (and flaps) and it just don't take off. After 3 attempts I'm about to throw the plane to the garbage. I have checked and rechecked throws, CG, gyro, EDF...everything according to manual and nothing. Are there more cases like these on this or any other models? Today was the 3rd crash trying to take off!!!! 😡 I have no problems with my other 4 planes (two 70mm, 1 80mm and a Freewing F-16 90mm) I'm curious because all this happened after I changed the fuselage. On the very first flight at least the plane was on the air, now it just won't take off!!! 🤬🤬

Thanks in advance for your feedback.

Madness that's very discouraging, sorry to hear it. There must be something way off. I have the original stock grey F-18 that I redid that ended up weighing about 1.2 extra POUNDS than the stock grey and I fly off of grass and she lifts off in 100 feet just fine. To make matters worse, mine has the original stock 9 blade 3748-1750 Kv outrunner, which Motion recently upgraded with the 9 blade 1900Kv inrunner (which I assume is in yours), so mine should be much less powerful than yours. I also have the 90 mm F-16, upgraded to the 12 blade 1835 Kv inrunner and my F-18 get's off in the same or even less distance. I'm using a RT 6250 mAh 35C battery in my F-18 (but the HRB 6000 50C in the F-16), which weighs in at 790 g and I fly it at a CG further back than the manual at around 97 mm (the furthest I can get it and some are flying at 110-120mm just fine). All I can recommend is to recheck the CG, get it to at least 94 mm from the recommended 88 mm and make sure that the battery you have has sufficient discharge capacity (C) to spool up the EDF to it's full potential. And keep in mind that just because a battery has a printed C of some number, that's definitely not what it really is. If you have a power meter, your EDF at full throttle on a fully charged battery (inrunner or outrunner) should be drawing somewhere around 117-120 Ah and 2600-2800 Watts. An inferior battery will be as much as 10-15% below that and will definitely affect the take-off. One last thing, with most EDF's, it helps to start the take-off run with full up elevator, thus relieving downward pressure on the nose gear and slowing it up on the take-off run (in grass it's even more pronounced). As it gets closer to lift off speed, you can relax the elevator so it doesn't shoot straight up and stall and you should then get a nice smooth take-off.

I will also tell you that in my case, I maidened it at 88 mm and it require a hell of a lot of up elevator trim to fly level, something like 5mm more than at the stock neutral location. If I remember, that was something like 50% up trim in the elevator.

Not sure any of this helps, and hope others with more knowledge than I have get to weigh in. Something definitely is holding your F-18 back. I suspect 1) not enough up elevator travel-neutral position not up enough & 2) not enough power from your battery.

[ColtPilot]

Here are the photos of the battery on it's CG position and the elevator at neutral.

Is the leading edge of the elevator at the 2mm below the fuse line as shown in the instructions? Mechanical positive deflection of the elevator is a must. I did the maiden on the 90mm HD Blue Angels and no issues with taking off with 100' run no flaps. Flew well. My battery is set back 1" back from the front of the nose gear motor casing, cg at 98mm.

[ColtPilot]

Here are the photos of the battery on it's CG position and the elevator at neutral.

Set the battery back farther from where you have it. I'm using a pulse 5000 35c.

[Hugh Wiedman]

Madness and don't forget that with the F-18 and flap deployment, although it increases wing lift at a slower speed, it also forces the nose down and requires at least an additional 10% of up elevator trim to get it to a level attitude. So with a more nose heavy CG and flaps, it will put even more downward pressure on the nose gear until you trim it out well.

[ColtPilot]

Madness and don't forget that with the F-18 and flap deployment, although it increases wing lift at a slower speed, it also forces the nose down and requires at least an additional 10% of up elevator trim to get it to a level attitude. So with a more nose heavy CG and flaps, it will put even more downward pressure on the nose gear until you trim it out well.

That's why I use flight mode for flap to elevator trim mix. So at each flap setting, you set the elevator trim. So you'll need more positive elevator at each flap setting.

[Hugh Wiedman]

That's why I use flight mode for flap to elevator trim mix. So at each flap setting, you set the elevator trim. So you'll need more positive elevator at each flap setting.

Absolutely agree ColtPilot , FM set to your flaps is the only way to go. I can't imagine how pilots who fly aircraft with flaps can possibly do it without that feature. I also enable it on the ailerons in addition to the elevator just in case the flap travel on each side is not exactly the same. Even with that feature, I still find myself occasionally adjusting the trim depending on wind conditions and when I'm messing around with trying different CG locations, sure makes it easy to deal with.

[Airguardian]

From the description of the problem, I bet you are way too nose heavy and use too little throws. Did you try high rates for take off?
This jet pops off the ground pretty easily, you clearly must be doing something very wrong.

[ColtPilot]

From the description of the problem, I bet you are way too nose heavy and use too little throws. Did you try high rates for take off?
This jet pops off the ground pretty easily, you clearly must be doing something very wrong.

Mine did a smooth transition on take off and didn't pop off the ground like I've seen some do. Have a geotech runway.

[Mizer67]

Well, from the photo it's almost certain that you're nose heavy. That battery is too heavy to be that far forward unless your aircraft is unique.

Your elevator deflection at rest doesn't look terrible in that position with a more neutral CG, but you could use some additional up elevator dialed in vs. what you have there being very nose heavy. I have about that much "up" elevator dialed in on mine at a CG of ~105mm and mine's not quite neutrally balanced (i.e. still a touch nose heavy).

My expectation is that with your current battery and it's length, unless you've relocated the blue box you could basically push it all the way back until it hits the MCB and still be a bit nose heavy for CG. I'm guessing the best you'll be able to do for CG with the MCB in the stock location is something in the mid-90mm range at that battery length and weight.

You've painted the plane, obviously. Did you weigh and balance the plane after painting? It sometimes can add a lot of weight and will change your balance as well. House paint (i.e. latex) is very heavy, for instance.

One thing I'll say is that this plane should take off very easily, even on grass, unless your cheater or fan is plugged. Mine rotates in the shortest distance of my two 90mms and does so very easily, especially if the nose gets bouncing (higher AoA). Granted, I'm using takeoff flaps, but even clean it gets off the ground quickly and easily with very little back pressure on the stick required.

[Madness]

From the description of the problem, I bet you are way too nose heavy and use too little throws. Did you try high rates for take off?
This jet pops off the ground pretty easily, you clearly must be doing something very wrong.

I always take of on high rates for this same reason. I use the recommended throws as per the books. Are you guys using something different? Like you said, I'm probably doing something wrong but so far it does not show what.

[Evan D]

Balance and or elevator travel...

[Madness]

Well, from the photo it's almost certain that you're nose heavy. That battery is too heavy to be that far forward unless your aircraft is unique.

Your elevator deflection at rest doesn't look terrible in that position with a more neutral CG, but you could use some additional up elevator dialed in vs. what you have there being very nose heavy. I have about that much "up" elevator dialed in on mine at a CG of ~105mm and mine's not quite neutrally balanced (i.e. still a touch nose heavy).

My expectation is that with your current battery and it's length, unless you've relocated the blue box you could basically push it all the way back until it hits the MCB and still be a bit nose heavy for CG.

You've painted the plane, obviously. Did you weigh and balance the plane after painting? It sometimes can add a lot of weight and will change your balance as well. House paint (i.e. latex) is very heavy, for instance.

One thing I'll say is that this plane should take off very easily, even on grass, unless your cheater is plugged. Mine rotates in the shortest distance of my two 90mms and does so very easily, especially if the nose gets bouncing (higher AoA). Granted, I'm using takeoff flaps, but even clean it gets off the ground quickly and easily with very little back pressure on the stick required.

The plane was painted with Krylon spray paint. The difference in weight was not significant, around 25 grams. As far as the battery (HRB 6000 50C), it weights 811 grams and it's not bigger than my Spektrum 5000 50C that I use on my Eflite F4 Phantom. Actually, I basically quit using the Spektrum battery in favor for the HRB which fits excellent, give me more runtime with even better performance. When you say cheater you mean Gyro? Do you have pictures of your battery location that you can share with me? I'll appreciate it!

[Mizer67]

This is a picture of my high rates. Plane doesn't need this to take off or land. I usually use mid rates or even low.

I've never measured them, but sometimes a picture is worth 1000 words. Apologies in advance for the bad lighting.

[Madness]

Is the leading edge of the elevator at the 2mm below the fuse line as shown in the instructions? Mechanical positive deflection of the elevator is a must. I did the maiden on the 90mm HD Blue Angels and no issues with taking off with 100' run no flaps. Flew well. My battery is set back 1" back from the front of the nose gear motor casing, cg at 98mm.

I'm using everything based on the book! Can you post a picture of you battery placement?