Official Freewing 80mm A-4E/F Skyhawk Thread

[e4dragongunner]

Ready to Rotate! And a little added insurance on the wing tips. :-)

I have a question. Per the addendum, it states not to fly initially with the Avionics Hump? please explain.
Additionally it also states not to add any slow down to the flaps, How would 1.8 seconds up and down hurt?

Many thanks!

Balanced at 193mm gear up!

[seaviper]

Looking good e4dragongunner! I run a 3 second deployment for flaps on all my birds including the A-4. I haven't noticed any tendency to nose over or balloon with flaps. Actually, I think most people experience problems with flaps because they are just carrying too much speed when they deploy them. Dumping flaps at warp 9 is usually not good.

[crxmanpat]

Flap slowing depends on your radio. If you are mixing in up elevator, some radios will only slow the flaps but not the up elevator trim, so you'll get some ballooning until the flaps catch up with the elevator. My old JR XP9303 slows both channels when set up in the Flap System menu, and I have mine set to 2 seconds.

[The RC Geek]

Interesting RC Geek. I balance the plane from the point where you slide in the guns. When I put down the flaps, the nose pitched down a lot more than the suggested up elevator/flab mix suggested. Based on your experience I wonder if I should move the CG back a bit and see if it eliminates the nose pitch. Thoughts?

I'm not talking about a pitch change when deploying the flaps but rather an uncommanded pitch up that occured at stall. When I had the CG a little further back, I had a couple tail strike arrivals resulting from the aircraft doing an uncommanded pitch up when getting slow in the flare. Moving the CG forward completely took care of this.

In what you're describing, I would recommend simply adding more elevator mix. The speed at which you deploy the flaps makes a big difference too.


Chris

[xplaneguy]

Chris, Was your initial CG based on measuring from the base of the gun or at the gun insert, aft? Check out post 588. For flaps or flying with tanks, I like 180-185mm from the gun insert, aft.

[spy]

hi all.
I just maidened mine today excellent flyer !! ..flap Ballooning ?No way the A-4 pitches down when flaps are down> you need UP Flap/elevator mix as outlined in Page 9 ( bottom of page) >> CG? no need to measure just look at the pictures @ the motionrc product update here > https://www.motionrc.com/pages/produ...df-a-4-skyhawk.
>>>>>> mine came with some problems .when I first put the wings on only the L aileron and Right Flap worked "together",,so I had to remove the wing connector plates and found the servo plugs > unplugged ,loose,and 2 in the wrong slot..it was not easy to plug it in correctly because the wires where really short...however the A-4 flew great just follow the updated manual..

[The RC Geek]

Chris, Was your initial CG based on measuring from the base of the gun or at the gun insert, aft? Check out post 588. For flaps or flying with tanks, I like 180-185mm from the gun insert, aft.

I was at the recommended 195mm mark. I'm probably closer to the 180-185 now. Flies beautifully there!

[crxmanpat]

My new fuse will arrive on Thursday, so by Friday she should be operational again (want to do the same weathering I did before). I'm out of town Saturday, but should be able to fly Sunday.

[ryramZ]

Decals done! A little matte finish and the shine off of Callie's graphics and the stock water slides all match. Love it! I want to do another.

[seaviper]

Looking good Ryan! Outstanding!

I flew this one today...film at 11.

[RFODOR]

I was at the recommended 195mm mark. I'm probably closer to the 180-185 now. Flies beautifully there!

That should make it more nose heavy. The battery is already full forward for 195.. Must be using heavier batteries than Admiral 5000.

[EDFNut]

Has anyone measured the installed thrust on the stock system yet?

Thx in advance

[EDFNut]

That should make it more nose heavy. The battery is already full forward for 195.. Must be using heavier batteries than Admiral 5000.

Just took a look at mine, looks like it'll take an 8000mah nano 25c easy.

[e4dragongunner]

Decals done! A little matte finish and the shine off of Callie's graphics and the stock water slides all match. Love it! I want to do another.

I love it!!! " I want to do another" My Thoughts Exactly! Really can't wait for the F4..... I just feel one is coming! Oh the Livery possibilities!!

[RCjetdude]

I got a second flight on mine today. My CG was initially at 195 mm from the reference point defined in the addendum (gear down and inverted though) when I maidened it with a RT 5800 35C (785 grams) all the way forward to the ledge she was a handful. I can't even imagine it being more tail heavy on take off if I had set it with the gear up. It was obviously tail heavy so today I put my heaviest battery in it. A Turnigy Heavy Duty 5000 60C which weighs 875 grams again all the way forward. It gave me a CG right around 182 mm (again gear down and inverted) It flew like a dream. Lifted off perfectly smooth this time flying Bullpups with half flaps. It flew as if on a rails with no I'll pitching tendencies like with the maiden. Very little flap to elevator mixing required and it settled in level with the throttle and full flaps for a perfect flare and landing. I am with Chris on where my CG is but check out how far forward my RT 5800 35C battery has to be to achieve the 182mm mark. I have the receiver, board and an A3L back and under the battery tray and had to remove the board mount and some foam to get it to work. I haven't even tried to fly it with the drop tanks which I know make it more tail heavy.

[RCjetdude]

I have an ARF+ on the way that I will be doing as a Blue Angels #6. Graphics from Callie are on the way. I plan to add servoless gear doors including a nose strut arm, lights, oleo mains and will be powering it with a Jet Fan 80mm fan unit and HET 2085kV motor running on a HET 125A ESC. That is my plan anyway. These things are like Lays potato chips...nobody can have just one.

[seaviper]

Redemption! I re-maidened the A-4 today. Last week I got in trouble fighting some pretty strong wind by pulling too much power on final. I dropped her in hard and damaged the nose gear mount area and a wing, among other things. It was bad enough I just decided to go ahead and get an ARF+. The bird I flew today is about 70% ARF + and 30% parts from the old bird. The other new parts are in reserve as spares.

I got in three flights today. The wind was unpredictable. From downwind to final the wind would change directions. This caused me a little concern. However the 80mm power unit on a 5000mah battery gave me plenty of time to take action. I flew the bird slick and with tanks. With tanks she might need 2 or 3 clicks of down trim. But speed wise, I saw no difference. I did not fly the hump.

This Skyhawk has the power to just suck up the gear after takeoff and go pretty much straight up. I love it. And it's locked in like the F-5. Actually it flies a lot like the F-5. I can see that this will be a fun bird to fly. Much less stress than trying to launch a 90mm jet on this runway.

My first two landings were greasers. The last one was a rather brick-like landing. And on that landing I ran over some FOD on the runway. The sound of hitting the FOD (white foam from someone else's bad day) and the heavy arrival made me think I broke the little Scooter again. But,as it turns out, the Scoot took the beating in stride.

After three flights I did have to re-tighten the grub screw on the steering arm, as well as take up some of the vertical play in the nose gear. I don't think the factory had loc-tighted the screw. It is secured now. I also went and put my nose wheel steering on a separate channel to aid in fine tuning the alignment.
Sometimes after a day of rough field ops, the nose wheel tracks a little one way or the other. Not often. But when it does, adjusting that screw and linkage under the nose can be an exercise in frustration.

Anyway, here are a few pictures and a video of all three flights. It's mobius cam video but not too awful bad.

[RCjetdude]

Ryan and Patrick, your A-10's look killer!

[xplaneguy]

Nice looking Skyhawks, Gents!

[Monty500]

RCjetdude: There still seems to be a lot of confusion regarding the correct point to measure the cg from. Can you confirm whether the last photo showing your cg measurement is your latest (185mm) or an earlier 195mm setting? Based on Xplaneguy/Ryan's posts (588 & 597 on page 30) it looks like your measurement in that photo to where the guns are installed is more like 200mm. Xplaneguy says that the cg should be measured from where the guns are installed. If the photo shows your latest setting then this may be 15mm to far aft?

Perhaps Ryan or Xplaneguy can clarify?