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

[DCORSAIR]

Got out flying today and put the Mig and 2nd Hornet painting on hold. The F-18 Canadian had been flying great with about 30 flights on it with the new 12 blade inrunner, but all of a sudden it developed the dreaded flap issue others have posted. This is the 2nd time out in a row that the left flap (I think), won't go down in flight, yet on the ground and even under pressure it works fine! Reduced the delay to 2 seconds and to 0, yet in flight it's dead! Man, it sure flies squirrely with only one flap in the landing position (drastic roll left-so assume it's the left flap not going down). Virtually uncontrollable until it gets raised. Next plan is to bypass the BB completely. I'd change the servo, but even under heavy pressure on the bench, it works fine, but if bypassing the BB doesn't solve it, guess I'll try a new servo!

I had no flap delay on my two F-18 and they both still did it, almost lost them both from the same issue, it's just crazy, also had one where the rudders would go left when I retracted the gear, that was fun on the maiden, I hated the way that jet flew anyway, never could get them locked in to what I liked. sold both of mine, problem solved...............

[T-CAT]

To be perfectly honest (a rarity for me) after going to landing flaps, it went violently out of control, spun towards the ground, and was able to get it nose up just before it went into the 10 foot high Everglades saw cane. The gear was already down since I was trimming it for landing configuration, so it doesn't seem that there was too much current draw. I then chopped and stumbled my way through the bush and was lucky to find it, completely unscathed (the jet, not me)! Truly a miracle that it ended up just above the bush, nose up with very little momentum.

T-CAT, I'd had an issue on an earlier flight where it seemed one flap wasn't working, so I had already changed the delay from 4 seconds to 2 seconds. Still happened and this time it happened so quickly it was hard for my molasses brain to react fast enough. Since bringing it back, I've tested both servos (with the GT Servo Tester) and they test out fine and seem to have plenty of torque, as I'm only using the middle control horn hole. I was going to swap out the servos, but not sure that will help, and since these servos are on ribbon cables, I can't really bypass the BB without running separate servo wires bypassing the ribbon cables.

Not sure where I'm going next with this. I could go to a 0 second delay, but really hate to have instantaneous flap deployment. That worked on my Avanti and both my B-24's that had the same issue (but those don't react as quickly as the F-18), but with those, one of the flaps (different one each time) would not return to 0 after deflection, but only noticed it after landing and putting the flaps up, so no issues in flight (unless I would have retracted them). I wonder if I should swap out the BB, although it worked fine for the first 30 or more flights even with a 4 second delay.

Need to get this worked out, especially since I'm working on a 2nd Hornet. The last thing I need are 2 uncontrollable beasts (already have those with my kids).

Dazed and Confused in Miami

Ugh, yeah that’s always difficult experiencing and diagnosing electronic issues like that. Hopefully you find a solution and have predictable flap action on future flights. I’m happy to hear that your jet is in great shape after that last flight!

[Hugh Wiedman]

Wow this flap issue is a real thing. I've had it happen on several of these models. Very intermittent. Looks like I should swap out the flap servos as well. Glad you were able to bring her down in one piece Hugh Wiedman!

To be perfectly honest (a rarity for me) after going to landing flaps, it went violently out of control, spun towards the ground, and was able to get it nose up just before it went into the 10 foot high Everglades saw cane. The gear was already down since I was trimming it for landing configuration, so it doesn't seem that there was too much current draw. I then chopped and stumbled my way through the bush and was lucky to find it, completely unscathed (the jet, not me)! Truly a miracle that it ended up just above the bush, nose up with very little momentum.

T-CAT, I'd had an issue on an earlier flight where it seemed one flap wasn't working, so I had already changed the delay from 4 seconds to 2 seconds. Still happened and this time it happened so quickly it was hard for my molasses brain to react fast enough. Since bringing it back, I've tested both servos (with the GT Servo Tester) and they test out fine and seem to have plenty of torque, as I'm only using the middle control horn hole. I was going to swap out the servos, but not sure that will help, and since these servos are on ribbon cables, I can't really bypass the BB without running separate servo wires bypassing the ribbon cables.

Not sure where I'm going next with this. I could go to a 0 second delay, but really hate to have instantaneous flap deployment. That worked on my Avanti and both my B-24's that had the same issue (but those don't react as quickly as the F-18), but with those, one of the flaps (different one each time) would not return to 0 after deflection, but only noticed it after landing and putting the flaps up, so no issues in flight (unless I would have retracted them). I wonder if I should swap out the BB, although it worked fine for the first 30 or more flights even with a 4 second delay.

Need to get this worked out, especially since I'm working on a 2nd Hornet. The last thing I need are 2 uncontrollable beasts (already have those with my kids).

Dazed and Confused in Miami

[T-CAT]

One thing to try/test to reduce the chance of the flap deployment issue occurring is to move the L-bend of the control rod to an inner hole on the servo arm (closer to the arm center screw) of the servo to achieve better torque from the servo. This will be at the expense of servo throw, but if you can achieve enough servo throw for the flap positions you want by using an inner hole on the servo arm, then an outer isn’t necessary or beneficial if you’re wanting to prioritize torque. It’s been a while since I’ve owned the Freewing F/A-18C, so I can’t remember which servo arm hole I used on the flaps for the linkage. However, then again, the flap issue could simply be from the stock servo not being strong enough for the job. It’s still worth a try .

It’s likely been discussed, but I haven’t kept up on this thread at all. If so, my apologies. I remember a discussion long ago about keeping the flap deployment speed in the radio to a reasonable amount because if too slow it could cause issues. I always had mine on 2 seconds or less and didn’t have an issue, thankfully.

[Aros]

Wow this flap issue is a real thing. I've had it happen on several of these models. Very intermittent. Looks like I should swap out the flap servos as well. Glad you were able to bring her down in one piece Hugh Wiedman!

[Hugh Wiedman]

Got out flying today and put the Mig and 2nd Hornet painting on hold. The F-18 Canadian had been flying great with about 30 flights on it with the new 12 blade inrunner, but all of a sudden it developed the dreaded flap issue others have posted. This is the 2nd time out in a row that the left flap (I think), won't go down in flight, yet on the ground and even under pressure it works fine! Reduced the delay to 2 seconds and to 0, yet in flight it's dead! Man, it sure flies squirrely with only one flap in the landing position (drastic roll left-so assume it's the left flap not going down). Virtually uncontrollable until it gets raised. Next plan is to bypass the BB completely. I'd change the servo, but even under heavy pressure on the bench, it works fine, but if bypassing the BB doesn't solve it, guess I'll try a new servo!

[Aros]

Yep Big Dave I've had several asymmetrical flap configs which really keeps you on your toes! I do have a 3 second delay so maybe I need to drop that to 2. Also, too much deflection at max settings and it would rub against the side of the fuse which would cause sticking issues as well.

[Evan D]

Many times the book setup is not a very good mechanical setup. On the FW F-18, from memory, the aileron, elevator and flaps all have poor set up when placing the pushrods in the designated servo horn hole and surface horn hole. I moved the push rod in one hole on the servo for each of these surfaces.

Doing so allowed me to use the servo travel at 100% (or more). This makes the servo work easier and with more resolution. One hole is about 20% easier the servo is working.

I hope that makes sense.

[Airguardian]

It's been debated quite a lot already.
Check that the flaps are not hard pressed when retracted (causing further load on the servos), don't use delay functions longer than 2s and in case of doubt, replace flap servos by beefier ones (more torque).

Anyway, how come you didn't immediately retract flaps as soon as that happened?

[Big Dave]

Had my 6th flight this afternoon. Most of it went well but upon setting up for landing and putting one notch of flaps in (what I’ve been using for landing) it started rolling hard right. It eventually went inverted and I pulled it out and was able to miraculously put it down with no damage. By the time I touched down I was full left aileron to keep it from rolling over. When I got to the plane the left flap was at position 1 and the right flap was up. I am hooked up to the blue box but have never seen this before today. Any ideas ?

[Airguardian]

I talked about this earlier too... thoroughly recommended to bury BB under tray to have clean battery compartment access. :)
My battery packs go fully 'under the roof' when installed on the jet :p



I have battery even further aft now than what is shown in the picture... but gives an idea :)

[Hugh Wiedman]

Evan D now those are some "Clean Machines". Your Mig wiring is impeccable, hopefully I can get close to that with mine, thanks for posting photos, just wish you would have done it a lot sooner to show me the way! Without these expert solutions, at least in my case, even a "Blind Squirrel Occasionally Finds a Nut"!

[Evan D]

It's a great place to put your receiver, light module and other things too. Most planes have room under the floorboards. I also clean up the wiring and close off holes and openings in the foam Here's mine.

[Hugh Wiedman]

While working on getting my 2nd Hornet ready for repainting, I removed the battery tray and the BB from it so I can put the BB further aft, making more room to move the battery back and get to my preferred CG. Then it dawned on me, there is plenty of room underneath the battery tray for the BB and all the wires. So then I went back to my 1st Hornet and pulled all the wires out and put them along with the BB under the battery tray. My receiver is up front away from the battery and pulled the wires up through the front of the tray. Before, I had a tough time getting my battery far enough back in that one especially with the 3D printed cockpit and full body pilot (all adding an extra 150 gr of weight to the nose) and all the wires were a real rats nest. I was forced to add lead weight in the elevator bay to get a decent CG, but now with cleaning everything up and coving the wires, I have plenty of room to move the battery around. I'll work on the CG tomorrow and no doubt will be able to remove some of that lead in my a...!!

So if you need more space to move the battery aft and adjust your CG, just relocate the wires and blue box. You may not need to do this with the stock cockpit, but it's an option that works well, at least IMO. The best part is covering up the mess of wires, including the wires for the afterburners.

[fredmdbud]

I never thought of that , using plastic film, please show picture

They're called "thrust tubes".

[fredmdbud]

.......

[steven gubala]

I never thought of that , using plastic film, please show picture

[Airguardian]

Thanks!
Put 4 more flights on her today and got some really cool shots!
I made my lowest knife edge to date... quite excited about that. Pucker factor was high! :o

And just installed some plastic film inside the nozzles to make the air come out 'straighter', giving a better neutral thrustline.
So far it seems to have worked perfectly, will post updates on the progress :)

[steven gubala]

Very nicely done Airguardian

[Airguardian]

Thanks!
I need to work them out a bit more though... I probably enter them too slow and then I need to rush them up and fast forward to the exit or the jet stalls!