Freewing A-4 Skyhawk 80mm EDF Assembly & Flight Review

How hot is Heinemann’s Hot Rod?

I keep telling myself to scale back on the foam airplanes, but when the Freewing A-4 Skyhawk came up on pre-sale, I knew I had to have one!  The A-4 is a classic design that I’ve always appreciated.  In fact, I still remember seeing the Blue Angels fly A-4s back in the 80’s.  It was such an agile yet graceful airplane to watch fly, they will probably always be my favorite Blue Angel aircraft.  The F-18s have brute force, but it just doesn’t have the grace and maneuverability that the A-4 did.

If you follow this page on Facebook or Instagram, then you know how this one ends for me.  For those who and for full disclosure up front, this airplane flies really well when setup right, but I actually crashed the airplane twice in the process of making this review…mostly a result of my own error.  The first time was due to installing an already flown battery into the airplane.  It only took a couple laps before the fan quit and of course it was too low to get back to the runway.  Bummed, but not to be defeated the airplane was refinished with a few upgrades (which we’ll talk about).  It came out beautiful, I loved it!  Unfortunately, the CG moved further back than I anticipated and the airplane over rotated on the second takeoff and I didn’t have enough altitude to fully recover.  It’s fixable, though I’ve debated just buying a replacement instead…it’s currently hanging in my shop waiting in limbo.

With that being said, I still wanted to provide this review because as I mentioned, the airplane flies really well.  But, it’s an A-4 and there definitely some things to be aware of when setting it up for best success.

AIRCRAFT ASSEMBLY NOTES

The A-4 is a quick assembly requiring the aft fuselage section be glued on and then the dorsal, horizontal tails and wings bolted onto the airframe.  From there, it’s just a matter of setting up the radio.  I did find that the dorsal was a pretty tight fit to get onto the fuselage and that the wings were a little fiddly too.  So, take your time to avoid dings and lightly clearance things if needed in the process.  That said, just to give an idea, the airplane was assembled in an evening and then test flown the following day.  Note that using 5 minute epoxy to attach the aft fuselage section is highly recommended.  I used the supplied urethane glue (being lazy) the whole glue joint got soft and the foam beads swelled.  It hardened up ok, but the texture was a little upsetting.

As a whole, the airplane is a really nice representation of the A-4 and it’s a great size for an 80mm airplane.  Not exactly 100% scale, but definitely pretty close and a really nice addition to the growing freewing 80mm line.  The finish is nice and quite smooth, definitely one of the smoother freewing airplanes I’ve experienced to date.  External wing tanks and bullpup missiles are included which is a nice touch.  I regularly flew with the tanks, but never flew with the bullpups.  The avionics hump is included as well which is kind of a must for an A-4.  There’s something slightly off about the canopy shape and I found that placing the avionics hump on the back actually made the nose section look more accurate, so the airplane was always flown with it on.

A couple of things that are worth pointing out are that all of the wing servos plug into a single connector which is nice.  This makes removing the wings easier.  Also, the airplane was packaged well, but there was one spot where the wing connector wire got pressed into the fuselage during packing.   It was a pretty deep ding, but easy enough to fix with some filler.  Unfortunately, there are no gear doors included with the kit.  I’m sure it was all in keeping the price down and keeping it simple.  However, this is a really nice looking airplane and I would have paid the extra to have those on the airplane out of the box.  The other thing is that though the nose gear doesn’t look bad, the main gear are a very non-scale trailing link style gear which kind of kills me (I just have this thing about landing gear… 😉 ).  If you want to upgrade, the 90mm Eurofighter mains (link is strut and retract as I was unable to find just the strut on Motion’s website) are a quick and easy replacement.

 

AIRCRAFT SETUP & CG

For the radio setup and CG, there are definitely some things to be aware of that will help keep the shiny side up.  First of all, A-4s are like deltas in that they need much more elevator than aileron throw.  As a whole, A-4s don’t need much aileron throw at all.  Freewing’s recommendations are way too hot, so be aware of that.  The airplane will roll like a drill bit with their recommended throws.  So, for the maiden, I setup the recommended low rates as my high rate and then added 2 lower rates from there.  Through flying the airplane, I settled on the following:

Elevator: 1/2″-9/16″ each way with 15% Expo

Aileron: 5/16″ each way with 10% expo

Rudder: 1-3/8″ with 15% expo to desensitize the steering

Flaps: 1″ mid and 2″ for full (no elevator mixing).

On the CG there are some things to be aware of here as well.  First of all, starting off a bit nose heavy is definitely recommended.  Once familiar with the airplane, then start looking at moving the CG back a little bit if desired, however through flying the airplane with an aft CG, the airplane would do an uncommanded pitched up when it got too slow in the flare with the power off.   As a result, there were a couple tail strikes experienced on landings.  Moving the CG forward alleviated the issue all together.

Based on this, I recommend setting the CG at 180-185mm as measured from the wing root gun cut out aft.  The airplane is a little nose heavy there, but it flies and lands really well at this location.  So consider this a starting point and then look at moving the CG back after a couple flights if desired.  Just be aware of the pitch up that the airplane does with an aft CG.  That’s where I got into trouble with the refinished airplane.

 

REFINISH AND UPGRADES

Before talking flying, let’s talk about the refinish and upgrades briefly.  I was so bummed with the crash as the airplane looked so good!

The first upgrade added was a nose gear door (download gear door template here!).  This was made out of sheet styrene and then hinged in the plastic cover that’s on the model.  3/16″ balsa stiffeners were added in the gear cutout in the fuselage to stiffen the cutout and also serve as a ledge for the door to rest against when closed.  For the door, the hinges were setup and glued first and then the perimeter of the door was lined with 1/16″ balsa with about 3/32″ space all around.  The door was then finished up by adding an inner cover from sheet styrene which really stiffens the door to help it hold its shape.  A spring was made out of 0.032 wire which pushed the door open and then some fishing line was used to pull the door closed as the gear retract (elastic cord works too).  The fishing line was fastened to the door and then the gear was retracted and the fishing line was pulled tight to close the door and the fastened to the fuselage.  The “just fly with tanks” choice was made to avoid making main landing gear doors since they basically hide the lack of main doors.

The second upgrade was the upgrading all of the struts.  As mentioned previously, the 90mm Eurofighter strut worked great for the mains.  The wire receiver holes at the base of the stsrut do require being drilled out which should be done carefully stepping up the drill size incrementally (pretty soft aluminum).  The springs are really stiff, so they were cut down such that there was no compression on the spring when the struts were fully extended.  The nose was also replaced with a specially built one my friend made for me.  He used the euro main strut and grafted the lower fork and tire from the Mig-21 onto it using epoxy and carbon thread.  It looked really awesome on the model!

The last bit of detail added were the vortex generators.  This was accomplished using some 1/4″ wide 0.020″ thick strip styrene plastic cut at 1/4″ lengths.  A template was made from a CAD drawing to plot out the VG locations and used a pencil to plot it all out (download the template here!).  From there, slots were cut in the wing at each location and the plastic pieces inserted, aligned, and glued with thin CA.

Lastly, on the refinish itself, a similar process to what has been shown in our warbird refinish and Kfir kit bashing series with the exception that neither the paint was stripped nor the panel lines filled in.  The stock airframe finish was lightly sanded and then all prep was done over that.  Additionally, instead of using 6 coats of minwax polycrilic applied with a foam brush, 2 coats were applied using a spray can version.

The weathering was similar to what we explained in our kit bash weathering video except that a lightened base color was used to fade the centers of the panels vs using a black shade over the panel lines themselves.  The black created too harsh a look based on the depth of the panel lines.  To bring out the panel lines slightly, Raw Umber acrylic thinned down with water and tamiya acrylic thinner was used as a wash and sprayed over all of the panel lines.  Once sprayed, the acrylic was wiped off in the direction of the airflow on the flying surfaces and vertically on the fuselage and dorsal using a paper towel and tamiya acrylic thinner.  For heavier streaking the unthinned raw umber was used in the same manner as described in the Kfir weathering video.  The weathering came out really nice and looked about perfect when finished.  Note that I plan to do a from the bench discussion later this year outlining all kinds of different weathering techniques and ways to use them, so just a heads up there.

One final item of business the airplane was screaming for was a centerline multiple ejector rack (MER).  I started this before the “incident” and finished it up after, so I never got a chance to fly with it on, but they came out really awesome.  If I do another A-4, it’ll be flying with this MER!  Note that the MER kit is available on my 3D Printed Products page if you’re interested.

 

FLYING THE FREEWING A-4 SKYHAWK

In short, when this airplane is setup right, it flies pretty awesome!  The airplane tracks well, has good authority and presence, and just looks good in the air.  It’s not the fastest 80mm jet out there, but it moves out decently and pulls well into the vertical.  Flying with and without the tanks, there’s a little difference in top end speed, but otherwise there’s not a huge difference in performance that was noticed.  My preference was to fly the airplane with the tanks as it made the A-4 a little easier to see and seemed to help the airplane track just a little bit truer in the air.

Through flying the airplane, covering the cheater aux air grate on the underside was played with by taping it over with no discernable difference in the aircraft flight performance noted.  In  fact, the airplane got a little quieter in the process.  The inlets themselves are at about 100% of the fan swept area, so there’s really no need to have the aux air grate underneath.  So, in the refinish, it was closed up more permanently.  One important thing to mention is to calibrate the speed controller before the first flight as this will ensure getting max power out of the fan at full throttle.  To do that, simply plug the airplane in with the radio on and the throttle at full.  Wait for the ESC to beep twice, and then bring the throttle back to idle.  The ESC will then arm and it’s all calibrated and ready to go.

Here’s a short flight video of the airplane in action.  This is the aircraft bone stock before the refinish with the tanks on and the cheater grate taped over.

 

FINAL THOUGHTS

There we have the Freewing A-4 Skyhawk.  This is a good  flying EDF that looks good out of the box.  A-4s do take some extra attention in setup, so keep that in mind and you’ll have a lot of fun with the airplane.  I do wish that gear doors would have been included, but I suppose not everyone is a staunch scale nut like myself.  I’ve been on the fence of getting another one actually, so that should say something about how much I liked it!

Double check that CG and you won’t crash like me…see you at the field!

12 thoughts on “Freewing A-4 Skyhawk 80mm EDF Assembly & Flight Review

  1. Great review and awesome paint and detail job. I love flying this plane. My only problem with the plane has been leaving the antenna on and catching it on something. It is now a shorter antenna.

    • Thanks! I hear you on those antennas, always an accident waiting to happen but totally worth it because they add a ton of character.

  2. Since you have the tomcat too do you think the skyhawk mains will fit the tomcat making the wheels rotate into a scale position?

    • The difficulty is that on the f-14, the wing carry through spar takes up the area that the tire would go when it retracts. So I think notionally that the retract units are similar size, but there’s nowhere for the tire to go when it retracts and rotates.

  3. Getting ready for the maiden voyage using your reccomend throws. I’ll be using the admiral 5000, what should I set the timer for on the initial flights?
    Thanks
    Richard

    • I’d recommend setting it at 3:30 for the first flight for insurance when landing comes in the event of a go around. Good luck on the maiden!

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