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Old Feb 28, 2014, 12:42 AM
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Build Log
Corsair F4U-1A by Parkzone Build Log

This is my set of notes covering my Parkzone Corsair. The main RC Groups thread for this aircraft is:

http://www.rcgroups.com/forums/showt...40767&page=181

General Notes
• This aircraft was poorly thought out and assembled, which is quite uncharacteristic for a Horizon product. The basic design, excellent wing loading and flying are great. Hoever, the lack of attention to detail and failure of a number of key components make this a “do not recommend” product in my book, especially with all the other options for Corsairs out there now. The saving grace is that the aircraft flies very well and Horizon has fantastic customer support.

• Positives:
- The aircraft flies very well. In fact, the stock setup has almost too much lift, so much so that landings can be a bit trickier because the plane gets bounced around a lot from the air currents near the runway pavement. A heavier battery and motor made a tremendous improvement in settling down the aircraft and made it much more fun to fly.
- Great appearance and paint scheme, nice looking pilot. 3-part flaps also look great, but are poorly designed and need CA or other hinges placed to keep from tearing off.
- Additional stickers for different numbering schemes included. However, the remainder of the markings were pre-applied (see negatives).

• Negatives
- Poor, flimsy flap design (see above). Needs fix with CA hinges.
- Tiny battery hatch only doesn't allow access or even view of receiver and servos. For this, the wing must be removed. Replacing the wing with the short stock servo connector wires was a pain so I added servo wire extensions for the flap and aileron servos to make replacing the wing easier. I don't understand this move to a small, annoying hatch, especially when their much better P-47 model had a great big hatch for easy access to everything.
- The model’s light weight causes wind to bounce aircraft around on landing (see above). Before changing to a heavier battery and motor I secured 8oz weight on the wing center at the CG which helped significantly at not much loss of performance. Eventually removed this when upgrading to Scorpion motor and using 3300mAh battery.
- Flimsy stock landing gear with fragile trunions. This may now be resolved with current runs of the model with improved trunion plastic strength.
- Ugly appearing wire landing gear with flimsy gear covers. One of which just fell off and was lost in flight after takeoff.
- Stock decals are not great and are plastic and stick-on appearing to me. They are pre-applied, which precluded changing these with better and more unique appearing decals as they cannot be removed without stripping off the coating on the foam and leaving a nasty surface defect. This is true of all Parkzone models. It would have been much better if the decals were left off and multiple different sent available to make each aircraft at least much more unique.
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Old Feb 28, 2014, 12:43 AM
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Stock Specifications:

Specifications (stock from Parkzone):
Scale: 11.4:1 approx
Wingspan: 44.0 in (1120mm) (real aircraft 41 ft 0 in = 12.5 m)
Overall Length: 36.0 in (915mm) (real aircraft 33 ft 4 in = 10.1 m)

Flying Weight: 43.4 oz (1230 g) with drop tanks installed; 46.6 oz (1320 g) with tanks, retracts and flaps installed
Is Assembly Required: Yes
Motor Size: 15-size 950Kv brushless outrunner (installed)
Plane Type: Scale Military
Power Plant Size: 10-15 Electric
Prop Size: 9.5 x 7.5
Recommended Motor Battery: 11.1V 3S 2200mAh 25C Li-Po
Retracts: Optional
Speed Control: 30-amp Pro Swith-Mode BEC brushless ESC (installed)

Control Throw (Ailerons): Low: 13mm; High: 18mm
Control Throw (Elevator): Low: 16mm; High: 20mm
Control Throw (Flaps): Half: 10mm; Full: 20mm
Control Throw (Rudder): Low: 20mm; High: 27mm
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Old Feb 28, 2014, 12:43 AM
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Center of Gravity (CG)

CG
• 64mm from wing leading edge is optimal for my aircraft
• The stock recommendation was 57mm from leading edge of wing at fuselage. Mine balanced at 63mm after assembly so I added 1.75oz in cowl at black motor to balance at 58mm with 2200 mAh 3S batteries and 2600mAh 3S commonsenserc batteries. The 2200 and 2600 batteries balance all the way forward. However, it turned out out that it flies best without added weight in the cowl and did better after removing the above weight.
• Note, with new Scorpion motor and 3300mAh battery needed .75oz in tail to balance
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Old Feb 28, 2014, 12:57 AM
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• The battery tray and strap were badly glued in and came loose during flight. I was lucky to spot it before it shifted midair which would have pushed CG back and possibly caused a crash. Glued it in with epoxy.

• Ventilation in battery and receiver compartment is terrible. Decent inflow exists in the cowl but there was no outflow so I put a 1x2 cm hole in aft fuselage at bottom to vent. For the stock setup heat doesn't seem to be an issue. However, with a larger motor and ESC it could be an issue. Also removed the plastic exhaust covers and cut holes through underneath to allow more venting.
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Old Feb 28, 2014, 01:04 AM
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• One main screw affixing the wing disappeared in flight despite having bee screwed in firmly. Replaced with M3-.5x25mm screw from Home Depot. Also used 3mm locking washers to secure both screws this time to prevent one falling out again.
• The retracts were poorly designed and the trunion broke twice on landing that were not severe. It turns out many others had this problem and Horizon eventually stated that the initial batch of trunions had “weak plastic” and sent complimentary replacement (plastic retracts). Why they couldn't just have used metal such as the ones sold at www.pw-rc.com I don’t know. Anyway, the new trunions seem to be holding up after another 50+ flights so this issue appears resolved.

• The gear covers are flimsy and almost a joke. They fall off easily, as one of mine did after takeoff, never to be seen again. Fortunately, excellent Horizon customer support sent spares. Drilled holes in gear covers and secured with small white thread to keep gear covers from falling off.
• Covered the ugly landing gear wires with Du-Bro plastic gear covers which I painted and weathered. This makes a tremendous improvement in the appearance of the model. However, this was much more finicky and annoying to do than it appeared.

http://www.rcgroups.com/forums/showt...3#post27602887

They make a big difference.
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Old Feb 28, 2014, 01:15 AM
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• After about 25 flights I noticed that the plastic around the wing screws at the back of the bottom of the wings was cracked on one side. I removed the wing to investigate and found that the front plastic wing joining piece simply fell off. Had this happened in flight it could have been a disaster. Perhaps this is why the wing plastic cracked. Anyway, the fix involved replacement of the plastic pin piece with solid carbon rods and a metal brass strip I had lying in my materials box. I used aluminum tubing around the carbon rods only for a better fit as my carbon rods were a tiny bit too small. Made sure the plastic receiver piece for the pins was epoxied in well also.
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Old Feb 28, 2014, 01:19 AM
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• Upgraded the flimsy, plastic-looking non-scale 2-blade prop to a Master Airscrew 3-blade prop. This results in more pull but slightly slower top speed, a very worthwhile tradeoff for the much improved appearance. Use acetone to remove the MAS prop markings and paint the prop tips yellow on the front and back for the best appearance.
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Old Feb 28, 2014, 01:32 AM
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• The stock 15-size motor was just too slow for my taste. It is designed for 3S batteries, and CANNOT be flown for any length on time on 4S without ruining the motor. What happens is that the motor, which has plastic components will grind itself into a useless mess at the front on 4S (I know this from my previous speed upgrade attempt with my Parkzone P-47, which is an absolutely fantastic model). Maximum speed with stock setup is around 60mph and the aircraft cannot do a straight vertical. Therefore, I upgraded to a Scorpion SII-3020 motor flying on a 3300mAh 4S battery.

Now the model flies around 90mph max speed and does straight vertical no problem.

Motor numbers:

Stock Eflite 15 (aircraft total weight approx. 1.30kg with TP2250 battery)
Gens Ace 3S 2200 mAh stock prop
27.3 amp 291W
Gens Ace 3S 2200 mAh MAS 3 blade 10x7
29.0 amp 306W
TP 3S 2250 mAh 45C MAS 3 blade 10x7
33.5 amp 388W 1.25kg thrust
TP 3S 2250 mAh 45C MAS 3 blade 11x7
39.2 amp 446W 1.54 kg thrust
TP 3S 2250 mAh 45C MAS 2 blade 10x8
30.1 amp 352w 1.02 kg thrust
TP 3S 2250 mAh 45C MAS 2 blade 10x9
30.8 amp 349w 0.95 kg thrust
TP 3S 2250 mAh 45C MAS 2 blade 11x7
39.1 amp 364W 1.15 kg thrust

Upgraded to Scorpion SII-3020-1110kV motor:
(increased top speed from approx. 60mph to approx. 90mph, unlimited vertical)
TP 4S 3300 mAh MAS 3 blade 10x7
76.4 amp 1076 W 2.27 kg thrust
TP 4S 3300 mAh MAS 3 blade 10x8
85.2 amp 1203 W 2.45 kg thrust
TP 4S 3300 mAh MAS 3 blade 11x7
105.0 amp 1445 W 2.60 kg thrust
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Old Feb 28, 2014, 01:58 AM
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• The flap attachments to the wing were flimsy, thin foam. This may have been done by Horizon to allow all 3 flaps to be moved with only one servo without too much resistance. The inboard flap with the control horn was loose on the right and came off from the wing during initial assembly, requiring repair with CA hinges. After the first 3 flights out of the box with the stock setup the left inboard flap also nearly ripped off on its own as well. Packing tape was a good temporary fix on the underside until CA hinges were used on that side also for definitive repair.

For the CA hinges, make careful cuts along the center of the hinge line on the flap side and wing side. Then dry fit to insure that you have good alignment. Then push the hinge into the flap, allow the CA to wick into the hinge and push into the wing. I had at least 10 seconds or so to make sure the alignment was correct. Afterwards, use epoxy to glue on the plastic joiner piece.
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Old Feb 28, 2014, 01:59 AM
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Transmitter Settings for DX18

Dual Rate/Expo
Pos: 0 1 2
Ail D/R: 60% 100% 100%
Ail Exp: 15% 25% 25%
Ele D/R: u55% d40% u100% d80% u100% d100%
Ele Exp: 25% 25% 25% 25% 25% 25%
Rud D/R: 100% 100% 100%
Rud Exp: 35% 20% 15%

• Differential +15%, Switch: ON

• Flap System:
Flap Elev
Pos 0: 100% 0%
Pos 1: 0% 2%
Pos 2: -85% 4%
Switch: Switch D
Speed: 3.0s

• Added slight crow / washout with gear down
- ON>RFL Rate -11% 0%, Offset 0%, Switch A
- ON>LAL Rate -10% 0%, Offset 0%, Switch A
• Thottle to elevator mix to decrease upward drift with increasing throttle
- THR>ELE Rate 4% 0%, offset -100%, switch ON
• Stunt flaps (flap move with ailerons/elevator in Flight Mode 3)
- AIL>LFL Rate 100% 100% , switch flight mode 3
- ELE>FLP Rate Up: -85% Down: 0%, Switch Flight Mode 3

• Timer: 4:40 with Scorpion motor and 3300mAh battery
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Old Feb 28, 2014, 02:04 AM
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History and Real Aircraft Specifications

Specifications

F4U-1A

General characteristics

* Crew: 1 pilot
* Length: 33 ft 4 in (10.1 m)
* Wingspan: 41 ft 0 in (12.5 m)
* Height: 16 ft 1 in (4.90 m)
* Wing area: 314 ft² (29.17 m²)
* Empty weight: 8,982 lb (4,073 kg)
* Loaded weight: 14,000 lb (6,300 kg)
* Powerplant: 1× Pratt & Whitney R-2800-8W radial engine, 2,250 hp (1,678 kW)

Performance

* Maximum speed: 425 mph (369 knots, 684 km/h)
* Range: 1,015 mi (882 nm, 1,634 km)
* Service ceiling 36,900 ft (11,200 m)
* Rate of climb: 3,180 ft/min (16.2 m/s)

Armament

* Guns: ** 4× 0.50 in (12.7 mm) M2 Browning machine guns, 400 rounds per gun 2× 0.50 in Browning M2 machine guns, 375 rounds per gun
* Rockets: 4× 5 in (12.7 cm) High Velocity Aircraft Rockets and/or
* Bombs: 2,000 lb (910 kg)

Aircraft Markings

http://www.markstyling.com/F4U_01.htm
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Old Feb 28, 2014, 02:07 AM
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I took a number of detail photos of the real aircraft:

Corsair F4U (Palm Springs Air Museum) walkaround
http://www.rcgroups.com/forums/showthread.php?t=2111668
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Old Feb 28, 2014, 02:57 AM
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This is a great thread, thank you Dray.

I used to not like my corsair very much, until I flew her with heavier batteries, and weathered her. Now she is the best looking of my fleet and I love to land her
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Old Mar 02, 2014, 03:11 AM
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Quote:
Originally Posted by Shung View Post
This is a great thread, thank you Dray.

I used to not like my corsair very much, until I flew her with heavier batteries, and weathered her. Now she is the best looking of my fleet and I love to land her
Agree!
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Old Mar 02, 2014, 05:49 AM
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It's a shame we can make gear door for this baby. I had a couple of ideas but the problem is that my wheel don't go deep enough into the gear bay. Same for you ?
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