Official Nexa 2100mm F-82 Twin Mustang (Balsa ARF) Discussion Thread

[tim hench]

The struts were so tight and grabby upon compression, I had to dis-assemble, polish the barrels inside and out and then grease the inside of the tubes and remove burrs from spring.and grease with some Super-Lube. Now they are sweet.

[Twowingtj]

do you epoxy the main wing spar tube in.

tim hench Welcome to Hobby Squawk!

The yellow paint is Rust-Oleum 2 in 1 spray paint, Canary Yellow. Krylon will work as well. No surface prep was needed other than a wipe down with alcohol and water.

The ESCs see attached to the top, inside of the firewall, battery compartments.

My wing tube is not epoxied in. It's slid in place and secured with 3 screws. One in the center wing section and one in each wing panel. This holds the quite securely. I put alignment marks on the wing tube and the outer ribs of the center section. This helps line up the center screw. Once that one is in place, the outer panel screws line up well. I didn't use the supplied screws for this. I went a little bigger and longer.

[tim hench]

moved battery tight to firewall the cg still don;t seem right 3/5/64th is that good to work with f-82 twin

[tim hench]

should the cg on twin f-82 work turned upside down , ckecked it upright need to add 1.19 pound up front, baffeled ?????????

[Evan D]

Yes, check low wing airplanes inverted. Bigger discussion is wheels extended or retracted. I do extended but many will argue that.

[tim hench]

how much weight do i need to figure in the nose to get cg, checking inverted f-82

[tim hench]

what kind of weights to buy for it

[Twowingtj]

how much weight do i need to figure in the nose to get cg, checking inverted f-82

That really depends on the weight of your power system.

I'm running 500kv motors on 6S 5000mah batteries. No extra weight was needed. I did have to alter the battery area to get them to fit.

[Spikedcheeto]

Hi, I was wondering if this plane is worth the effort and how much room do you get inside the plane? I want to run gas so what's someone recommend for good size gas engine?
Thanks

[Evan D]

Gasoline? It takes a .45- .50 glow. My suggestion is to reconsider unless you have a lot of experience with IC twins. A dead stick on one motor takes a good pilot to fly her in and a war bird is worse than most.

[TwistedGrin]

Thinking about jumping in one of these ARFs.....running possible set up using components I already have:

Motors: E-flite Power 52 590Kv (346g each)
ESC: Spektrum Avion 80Amp
LiPo: 6s 50c 5200mAh
Prop: XOAR PJN 12x8x2
Hitec HS-645MG servo's

e-Calc provides results as following:
Weight: 14lbs
Wing Area: 48.1 dm2 (SWAG)
Power to Weight: 189W/lb
Wing Load: 43.3oz/ft
Stall speed: 34mph
Top speed: 85mph
Mixed flight time: 9.1min
Max Amp Load: 59.7A
Max Power 2530.4W

Nexa does not provide numbers for Wing Area....so I inserted SWAG values to arrive at a Wing Load (43.3oz/ft) ....this is heavy but allows e-Calc to provide some numbers.

I fly several twin configuration models but run them in series or parallel.....this model wires each fuselage LiPo direct its ESC (save weight on wiring cables and connectors)?
I am accustomed to powering the electronics via separate battery (RX Battery) .....perhaps this model could use one fuselage side flight battery with an external UBEC to supply power?

My concern is the lateral imbalance....don't deploy a separate Rx Battery that would otherwise make one side heaver than the other?

Finally.....I prefer counter rotating props ....but understand some don't bother with this.....

Comments welcome and thanks in advance

TwistedGrin

Black Horse Dornier 335
Flightlne P-38
FMS TigerCat
FreeWing AL37
HobbyKing B-17
HobbyKing DC3
Nexa OV-10 Bronco
Seagull Cessna 337
Seagull Mosquito (RIP Failure)
Seagull Mosquito (RIP Failure #2)
I hang my head in shame and accept defeat on SG Mossies

[TwistedGrin]

I have made the jump.....now awaiting the bird and servo's, LG struts and prop spinners and graphics.....with all the strategy for storage and transport and maintenance regarding the wiring......this bird may take me awhile to complete

TwistedGrin

[Twowingtj]

Congrats! Looking forward to following your progress.

[TwistedGrin]

The suggested retracts from MotionRC for this bird are out of stock.....will be interesting to see if the X-Wave retracts will work after I receive the bird.

Continuing to study the performance from various motor/prop/battery/ESC power usage numbers via e-Calc...looks like twowinggtj's 300gram Turnigy NTM 4258-500Kv 14x8 prop package is very close to the 346gram E-flite Power 52 590Kv 12x8 prop package ...I find this interesting considering the difference of prop size alone!

TwistedGrin

[TwistedGrin]

ADVISORY ALERT:

The NEXA F-82 delivers equipped with Retracts and Landing Gear Pre-INSTALLED.

Contrary to the list of equipment "Required" on MotionRC WebSite:
Retracts are not required via separate purchase
Landing Gear Struts are not required via separate purchase

Advisory Complete

TwistedGrin
Also Noting: The model is delivered with pre-hinged and glued control surfaces.....Aileron, Flap, Elevator are Dubro Nylon Flat hinges / Rudder hinges are CA

[Twowingtj]

The supplied retracts and struts work great, zero issues.. The struts are sprung perfectly for the weight. I did lube the pistons with silicon and work them a bit to smooth their movement out.

[Bellke]

ADVISORY ALERT:

The NEXA F-82 delivers equipped with Retracts and Landing Gear Pre-INSTALLED.

Contrary to the list of equipment "Required" on MotionRC WebSite:
Retracts are not required via separate purchase
Landing Gear Struts are not required via separate purchase

Advisory Complete

TwistedGrin
Also Noting: The model is delivered with pre-hinged and glued control surfaces.....Aileron, Flap, Elevator are Dubro Nylon Flat hinges / Rudder hinges are CA

I'm on the fence with this one.. please keep the info coming. Looking forward to seeing the build.

[TwistedGrin]

Nearing the completion of my assembly:

Notes:
I needed 350g nose weight to achieve 96.5mm CG (inverted wheels retracted)
This leaves me "some" room to move my batteries forward if needed
I also needed to deploy the battery tray at the very bottom of the fuselage cavity
Supplied plastic spinners warped (Unusable) - Deployed ZYHobby 3.25in Aluminum Spinners
ZTW 85amp ESC's mounted inside motor boxes
ZTW 18amp BEC left side fuselage pulling power from left side 6s 50c 5200mAh flight battery
Aura8 Stabilizer Brick mounted to left side center wing
ElectroDynamicsInc 3pin quick connects for each fuselage
ElectroDynamicsInc 2pin quick connects for each wing
Hitec HS D645MW Servo for Aileron, Elevator, Rudder
Hitec HS 85BB servo for Flaps

My right vertical stabilizer was biased with an inboard warp....managed to get most of it out during epoxy cure. I still wound up with some inward angle which now translate to a slight curve in the horizontal stabilizer.....washers on top of the wood elevator tangs help mitigate most of the curve.

Both cowlings had issues mounting evenly to the right fuselage.....the left fuselage cowling mount is easily perfect. Larger cowling screws were used to secure each side.

I noticed there are left and right control horn slots for each flap - I managed to get one of them on an opposing side of the other two - forcing me to deploy a servo reverser for that servo.

Used 3mm socket bolts for the wing spar....tapped the spar for 3mm bolts for Left-Center-Right wings

Aura8 Stabilizer control brick mounted to the center wing underneath left fuselage with two Spectrum Receivers to which the right receiver is mounted inside the right center wing for DX8 Radio

I chose not to run a parallel battery loom....mostly for weight savings and the XT90 dual connectors would also encumber the batter compartment and I would still need a RX power supply somewhere.

To add a little color variation I opted to paint the elevator and rudders and wingtips red. I found the plastic wing tips needed sanding and primer coat for the "Valspar Project Perfect" rattle can red to adhere.... I think the plastic caps still had some release molding residue I could not remove !! Figured I'd fly this color splash and see how it looks to me before painting some more.

Tuning the flap servo's it is mechanically impossible for the 85BB servo short arms to reach the 35mm deflection....I am installing longer servo arms and also flipping the control rod connectors to the tops of the servo arms.....otherwise the angle from the flap horn will also bind up.....I am not too confident the power of the servo's either...time will tell

The tailwheel control arms prevent full range of rudder servo movement if you attempt to use the outer hole of the rudder control horns.....therefore the inner most hole of the rudder control horn may be the only means to get the full range for the suggested manual 35mm rudder travel.

At the moment I plan on storing and transporting with the twin fuselage and tail section fully assembled.....separating the two outer wings for quick field assembly.

I use eCalc with excellent results in my other models......eCalc is showing the smaller 12x8 props on my 6s LiPo and 85ESC combo is a sweet spot.....172watts per Lb / 85mph WOT / 9min flight duration at 72% throttle / 62amps at WOT

My total all up flying weight is heavy at 16.04lbs and if I used the correct wing area number 50dm2 this could have a wing loading at or near 47.7oz/ft. This explains the stall speed at or near 36mph......I usually try to fly at less than 41oz/ft....so this bird may have to land a bit faster than I am used to.

TwistedGrin

[TwistedGrin]

I am still holding for a day to maiden....need my skill level refreshed and ready for a maiden in favorable weather and runway conditions......as I look back on my years of flying and maidens.....90% of my losses are the month of March......too impatient to wait for a good day and too eager to maiden when my reflexes were not ready

TwistedGrin

[davegee]

I am still holding for a day to maiden....need my skill level refreshed and ready for a maiden in favorable weather and runway conditions......as I look back on my years of flying and maidens.....90% of my losses are the month of March......too impatient to wait for a good day and too eager to maiden when my reflexes were not ready

TwistedGrin

I Hear 'ya, TwistedGrin! Sometimes it's hard to know when to walk away and come back on a better day. I've lost a few where I should have punted that day and come back when conditions were better!

Good luck with it, whenever the time is right to do your maiden!

Cheers

Davegee