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

[thmprusmc]

Micro servos on each side? Would you mount them forward of the SB or aft?

[fastforward]

For those worried about the tall nose strut, it's actually the same length from the ground to the retract plate as the Avanti... reputed grass king... so. I wonder if because much if the strut is exposed under the fuse that to the eye it appears significantly longer, but in reality, it's not. It's the same total length as the Avanti.

In terms of wheel size, the A-4's wheels are the tallest of all Freewing's 80mm jet's wheels, and in fact the A-4's wheels are taller than the big F-14, MiG-21, 90mm F-16, 90mm F-15, 90mm F-18, 90mm Venom, etc...

A-4 = 50x15 Nose and 65x17 Mains

By comparison, most of our big 80 and 90 jet's wheels are slightly smaller: nose is 45x15 and 60x17 or so on most aircraft mentioned above...

If any of you are operating the aforementioned aircraft on your grass, by these numbers the Scooter really shouldn't be massively less capable.

I have been "on the fence" about the A-4 for months and my greatest concern was the tall nose gear. After the long consideration, I finally ordered the A-4 last Friday. Subsequently, I found Alpha's post on the subject of the nose gear. I'm resting a little easier now and anxious for the big brown truck to deliver my A-4 Tuesday.

I do not have the luxury of a paved runway to the larger wheels are a bonus. I have been watching videos of the A-4 landing silky smooth and nose high. I am looking forward to practicing landings until I can get them right.

As I mentioned, subsequent to my purchase I have been reading posts about the A-4 on the Hobbyquawk thread, I'm up to page 5 and still reading. I will pay close attention to the balance and error on the nose heavy side for early flights.

Bob DeGood

[Bobaroo]

I have been "on the fence" about the A-4 for months and my greatest concern was the tall nose gear. After the long consideration, I finally ordered the A-4 last Friday. Subsequently, I found Alpha's post on the subject of the nose gear. I'm resting a little easier now and anxious for the big brown truck to deliver my A-4 Tuesday.

I do not have the luxury of a paved runway to the larger wheels are a bonus. I have been watching videos of the A-4 landing silky smooth and nose high. I am looking forward to practicing landings until I can get them right.

As I mentioned, subsequent to my purchase I have been reading posts about the A-4 on the Hobbyquawk thread, I'm up to page 5 and still reading. I will pay close attention to the balance and error on the nose heavy side for early flights.

Bob DeGood

My NoseStrut/Connecting Pin took a beating early on. Very Soft Aluminum up there. I had a rearward cg too on the Jet and it Flew great ! Just hard on that Strut. It got all messed up and the pin is still loose on that one. On the next one, I'm gonna add a Brace and Reinforcements up there to keep it from getting destroyed. GL

[Bobaroo]

Micro servos on each side? Would you mount them forward of the SB or aft?

Forward !! cg dependent of course, The Linkages would work either way. There will be considerable Force applied to these when Open (Even on that little 50mm SA A-4F) Soooooooo, a set of strong Servos is required on these. I ended up using servo Over-Centering in the Deployed position on the LittleGuy to 'Lock' them out when opened !! They stayed there and took the Force without a problem They are of course Reinforced with PolyPly Fiberglass Sheet, and rigidity is essential in this business (You don't want one side collapsing on you in flight) where Aerodynamic Stability can be dramatically altered by a structural failure back there !!

A great Mod really, and it looks cool. GL should you give it a try. Cheers

[Elbee]

My latest project.

TM, Beautiful Work! Welcome to 'The Squawk'. Best, LB

[thmprusmc]

Getting some more work done. Painted the under side of the spoilers, added detail to a wing and added Naca vents on the nose area.

[Alpha]

Your scooter is looking magnificent, Thmprusmc! As a bit of a "blast from the past", here are some photos of our later stage A-4 prototype back in 2016. This is after we had upscaled it from the initial 70mm prototype. Even back then, we knew that split flaps were a must-have, even though they were plastic and expensive. From this CNC'd foam prototype to your customized production bird, all of us at Motion RC are very gratified to see these labors of love find loving homes and hangars.

[Evoman]

Your scooter is looking magnificent, Thmprusmc! As a bit of a "blast from the past", here are some photos of our later stage A-4 prototype back in 2016. This is after we had upscaled it from the initial 70mm prototype. Even back then, we knew that split flaps were a must-have, even though they were plastic and expensive. From this CNC'd foam prototype to your customized production bird, all of us at Motion RC are very gratified to see these labors of love find loving homes and hangars.

I am curious to know the main reasons that it was decided best to scale up the A4? Just want to know the determining factors in RC development.

[EA-6B Geek]

Super cool Alpha! Thanks for posting those photos.

[thmprusmc]

Alpha-

Thanks for sharing, Great to see the prototype!

[Alpha]

I am curious to know the main reasons that it was decided best to scale up the A4? Just want to know the determining factors in RC development.

After testing the 70mm prototype, our development team all agreed that the overall behavior wasn't what we wanted in a mass market Scooter. Upscaling to 80mm resolved our concerns in terms of :

Performace: The 70mm was fast, but the wing loading was higher and landings were less forgiving. The 80mm sized airframe was still quick but landed much more slowly and stalled more gently.

Proportions: The rotating undercarriage required a thick wing, which looked badly disproportionate on the 70's wing. Even then, the 70's wheels were too narrow. An 80mm sized wing allowed both thicker wheels and better model proportions overall.

Price: Short grass capable rotating retracts required a new design and be part which means added cost. It's easier to offset that cost with a larger 80mm sized airframe. Controlling cost while balancing feature set is always a critical consideration.

Precedence: The foam A-4s from Blitz and LX in years past were 50mm and 70mm, respectively. Our development team wanted to do something different, so we chose the larger undercarriage, larger 80mm EDF, larger overall size, and the modular magnetic avionics hump.

[e4dragongunner]

Great insight Alpha! Thanks for sharing. Love my Scooter. Need a second, "JUST CUZ"

[Evoman]

Thanks Alpha! It was really interesting to read about the determining factors that led to finding the ideal scale size.

[RCjetdude]

Is the foam CNC'd in the prototype?

[RC30Flyer]

Just purchased the A-4... awesome looking jet, but am I the only one that thinks the QC on these freewing jets is seriously lacking? The fit and finish is excellent, however, every single piece of wood to foam was either not glued in or has one little dribble of glue. The fan assembly was bouncing around on the mounts, the battery tray was loosey goosey, and the ESC hold down wood strap wasn't even tight. I'm now concerned about the retract assemblies and how well they are attached. I'm a fair modeler, and don't mind reinforcing things, but for the price I think these items need to be better installed at the factory. I have a 90mm F-16 waiting in the wings for assembly. Hopefully that one will be better.

[RCjetdude]

Just purchased the A-4... awesome looking jet, but am I the only one that thinks the QC on these freewing jets is seriously lacking? The fit and finish is excellent, however, every single piece of wood to foam was either not glued in or has one little dribble of glue. The fan assembly was bouncing around on the mounts, the battery tray was loosey goosey, and the ESC hold down wood strap wasn't even tight. I'm now concerned about the retract assemblies and how well they are attached. I'm a fair modeler, and don't mind reinforcing things, but for the price I think these items need to be better installed at the factory. I have a 90mm F-16 waiting in the wings for assembly. Hopefully that one will be better.

Welcome to HobbySquawk! I recommend entering a ticket with Motion so they can be made aware of the issues. All three of mine have been fine.

[RC30Flyer]

Thanks RCJetdude, I did talk with a guy on their online chat about some gator skin on the tail cone and he seemed to sorta blow me off by saying that's normal according to the batches they receive. Kind of disappointed with that answer after spending over $1400 with them in my last order. And the way the rest of the jet was almost flawless, but it is what it is I guess... Do you think the landing gear will be fine, or should I stress test them a bit? Also, been seeing a lot about this jet having a huge range for CG, is the 185mm the standard that most are using? Thanks again!

[RCjetdude]

Pull on everything to make sure it is secure and check it frequently. Mine had a bit of minor gatoring in places..nothing significant to me. As far as the CG goes I run mine around 180mm from where the large base of the canon mount and the flat on the wing root meet. Early on the reference point to measure the CG from changed. The manual online measures it from the same point I reference but places it back at 195mm which to me did not feel right on mine. Elevator was very sensitive and I almost lost the plane on it's maiden. I have had two more since and they both do well at 180mm.

[RC30Flyer]

I may be a little OCD with my wiring... ;)

[Bobaroo]

I may be a little OCD with my wiring... ;)

Possibly !! Hahahaha