DiscoWings

My Feedback: (76)

Rex, can you do an external horn on the flower hinge flaps? How would you do this? I asked James about this and he replied, just cut the regular honrs. I"m pretty sure this was supposed to have been done at the factory, can you let me know if the F-18(s) you have put together, were they done at the factory or did you have to do the horns for the flower hinge flaps?

Also on a side note, I've decided to go with the 7980s all the way around except for the nose gear, this was because I needed the HS-7950s on another plane and did not have any more, I'm sure the rudders and flaps don't need the power of the HS-7980, but since I needed the 7950's it will be 7980 all the way around.

lastly, what should be the distance of the horn from the hinge line on the aileron? Should be the pivot point be exactly on top of the line, in front or behind?

DiscoWings

My Feedback: (76)

Some updates:

Started working on the wings, I will go with the 7980's all the way around, but you have to open up the servo bays a bit, not much. Fly Eagle now pre-installs the servos for he flaps but looking at my servo bay either they PUT the WRONG servo box for the flap or they just have the wrong boxes. The Box was far too low into the wing not giving enough space for the arm. I had to add 6mm (1/4 inch) worth of extra plywood to raise it up on each of the rails, this finally gave the correct cleareance.

Next time to drill out a hole channel for the flap linkage, I still don't have the correct horns from Fly Eagle so I'll have to make something on my own. Also I think the length of the push rod is too small if you plan on using the small blue pin link on the servo and large one on the horn. On a side note, the Hitec blue servo arm is perfect for this, I drilled out the outermost hole to 3mm. (For Ailerons I will use the 2nd most outer)

I"LL upload the pics later, right now RCU is giving server 500 error...

rbxbear44

My Feedback: (86)

Just sent you a few pics of the Ailerons and external flaps setup I did. Also, a video of the flap movement and geometry.

Hope this helps.

Rex

DiscoWings

My Feedback: (76)

Nice cold day, so what to do? BUILD.

Since RCU's image system is down I put the pics on flicker:


1st is the Flap install:


Start out but cutting using a dremel with a router bit or even a drill machine a hole where the servo linkage will travel through.

Then you can mark the place where the horn for the flap will be. FEJ is too lazy to give you a proper horn so you'll need to cut one of the other horns to fit:




now its on to the alierons:


I will be using double horns with a ball link, I find this to be the strongest setup, 30 min epoxy mixed with BVM milled fiber 1/3 fiber ti 2/3 epoxy.

NOTE: I got the option of the light kit and FEJ has an upgrade for the light kit aileron cover that includes the nav light, however, the rails sit too high so you have to bend the fiber glass cover a bit to get it to sit just right:

DiscoWings

My Feedback: (76)

Some things to note:

1, FEJ included a string form ailerons to the root that you can use to guide the servo wire... sounds good until you realize that the damn string is glued into the fuse and can't move[:@]
2, There is no clear channel for the flaps to go back to the root, your going to have to drill out your channel to get the flap servo wire to out of the wing root. It is a PIA so make sure have you a long drill pit or an thin extension.

rbxbear44

My Feedback: (86)

I never use the strings they install...I always tend to route my wiring a different way anyway. The main reason is...they do not allow for safety clips for the servo extensions to pass through AND they don't always match up with the entry point to the Fuse. Just a part of the build...it's that way on pretty much all the brands.

Is there a hard mount block in the Flap for the control horn? That's why I went with external...huge surface to move with lots of "blowback" load when deployed. The god news is, if you have to beef up that area for a good anchor, it's easy to hide it once the surgery is done.

Looking good, man!

Rex

DiscoWings

My Feedback: (76)

Yes there is a hardwood block for the flaps, ODLY enough the ailerons did NOT have a hard wood block so I had to fill it up with epoxy/milled fiber to make a solid base before installing he the horns. The only hardwood portion that was on the ailerons was the edges so I had to make sure not to cut into them too deep.

I checked the results on the ailerons they are solid and firm grounded to the bottom skin of the aileron.

rbxbear44

My Feedback: (86)

Yea, as long as you spread the "load" and put some "mass" in there, it will be fine.

Keep er' going!

murdock0700

Duck,

I think I would trade in that chain saw and hatchet for a dremel tool for cutting out those control horns. Good grief.

HM

dubd

murdock0700, I'm sure many feel Discowings started off on the wrong foot on RCU, but that post is completely unnecessary. At least give the guy a break in his own build thread!

DiscoWings

My Feedback: (76)

Its under the wing, I could careless if its not exactly striaght, main thing its strong and won't move about.

gunradd

My Feedback: (9)

I suggest you reach out to Boli or Luke to find out the mods they did to make their F18 work. They had rudder flutter elevator flutter and the slats didn't work. This plane needs lots of mods to be an everyday flyer.

Also be careful cutting horns like a wedge shape like you had. That will be a stress point now and prone to breaking. If you round out the sharp edge inside it will help get rid of the stress.

DiscoWings

My Feedback: (76)

Ok some updates, after seeing dubd's unfortunate crash I'm really looking closely into the structure, My jet does not have the elevator bracket.

I have asked James to send my the plywood bulkheads and fuse ribs.

1 thing that is very interesting if my elevators servo is glued into the fuse with 2 plywood braces and 1 honey homb.

The rudder servo tray is in plywood and the other side in honey comb, but both are glued not using screws.

I will be doing carbon fiber reinforcing through out the fuse.

DiscoWings

My Feedback: (76)

Thanks gunrad,

my version is with the fixed canopy and does NOT have slats.

Cutting honeycomb is not as easy as fiberglass so getting a perfectly stright cut is challenging. I have however put a good amount of milled fiber with epoxy and am using 2 horns, it should be rip out the aileron before it breaks the horn I was able to see the F-18 fly in person at the Houston Jet Rally:

[youtube]http://www.youtube.com/watch?v=WFjDAcCiu_Q[/youtube]

jetpilot

My Feedback: (48)

That looks like honeycomb with carbon laminate on both sides which is probably awesome compared to what dantley had.
Scott

gunradd

My Feedback: (9)

The F18 I saw at FLjets had the same exact system Dantley had on his tomcat. He had 2 8711 servos on it I think.

Yours is totally different.

dubd

DiscoWings

My Feedback: (76)

well damn, maybe the already changed the setup, what do you guys think I should do? James is sending me all of the plywood ribs to replace the honey comb or glue right along side it.

DiscoWings

My Feedback: (76)

here is an updated pic showing what is honey comb and what isn't

dbsonic

My Feedback: (3)

Disco, wherever a bolt goes through the honeycomb, you should apply a doubler. Basically anywhere you see something "mounted to the honeycomb", I would apply a plywood doubler or change it to a hardpoint. I guess that's your vertical fin servo mount that needs this treatment. The honeycomb in your case looks painted or they did the old trick of mixing graphite in the resin to make it look like a carbon weave. (Even if it were carbon it would still get crushed without hardpoint or sandwich.)

Separate from that, I see they did use carbon in a few places for you and in addition you have some key servo mounting plates that are mounted to real ply formers. So that part is good(the part you mark in red).

dbsonic

My Feedback: (3)

hmm. now the teflon. Is that mechanically mounted? Glue is not sufficient(because its teflon). That needs to be mechanically mounted as well, i.e. with screws or bolts. Something to that effect.

DiscoWings

My Feedback: (76)

the cover on the honey comb doesn't look like carbon fiber almost like some black fabric?

I have some carbcon/kevlar weave coming form James Down dist. along with some west systems epoxy for renforcement.

The feflon seems to be glued and then also screwed in from the plywood side.

I tried to move the elevator bracket, its solid and not moving. However, the turbine mounts are flexing so will need to do some work there.

I"m waiting for FEJ to send the plywood ribs they said they would be sending all of the ribs in plywood. Should I rip out the honeycomb ribs and replace with the plywood, or just stack the plywood behind the existing honey comb?

Based on what I am seeing I am more concerned with the rudder as this tray is hte that is mounted into the honey comb and has screws going through the honey comb.

bevar

My Feedback: (27)

Be ready for your rudders to flutter if you use the stock set up. If you use the direct drive set up on your stabs, they will flutter too.

Beave

gunradd

My Feedback: (9)

Disco screws through honey comb is a very bad thing. Cut that stuff out and use the wood formers with hysol.

DiscoWings

My Feedback: (76)

Ok so rudder formers will be ripped out... what about the elevator, it has a total of 4 1 is on the honey comb but not screwed in.