|Wingspan:||18.11 in. / 460mm|
|Wing Area:||57.4 sq. in. / 3.7 dm. sq.|
|Weight:||2.3 oz. / 65g|
|Weight Flown:||2.5 oz. / 71g|
|Length:||16 in. / 406 mm|
|Wing Loading:||8 oz/sq. ft. / 20 g/ sq. dm.|
|Battery:||150mAh 7.4v LiPo Balancing with JST|
|Motor:||5g Brushless 2000kv|
|ESC:||Turnigy 6 amp|
|Typical Flight Duration:||6 minutes|
|Available From:||Hobby Lobby|
Let’s be clear from the beginning, this is not a plane for beginners. In fact, Alfa Models says in the opening paragraph, “The model is not intended for beginners." But for you advanced flyers, this is a heck of an aircraft with detail galore.
You can decal the P-51D in three versions: The Cripe’s A’ Mighty flown by Major George Preddy, Officer Commanding the 328th Fighter Squadron, 352nd Group, Christmas Day, 1944; The Slender, Tender & Tall flown by Major William Halton, Officer Commanding the 487th Fighter Squadron, 352nd Fighter Group, April 1945 or; The Petie 2nd flown by Lieutenant Colonel John Meyer, Officer Commanding the 487th Fighter Squadron, 352nd Fighter Group, August 1944. All are beautiful and complement the excellent detail molded into the Alfa Model P-51D.
The P-51D is made of extruded polystyrene (EPS) and requires the builder to pay attention to the weight. Everything about the design is directed at rendering a scale model including a semi-symmetrical wing, symmetric section of the horizontal stabilizer, detail right down to the engine air inlet and metal skin with rivet detail. Typically flown as a three channel aircraft, everything is included to add the rudder and make the P-51D a four-channel aircraft. Weight is the primary directive in adding a fourth channel.
The build is straightforward, but requires one to understand CG, weight and some soldering of ESC connections as necessary. Decals must be applied and are water based, so an additional video is available to better understand this process. Those of us that grew up building plastic models likely know the process of water-based decals.
As a micro, the kit is small and packs into a box like a large pair of shoes. The materials are well protected with the ESC and accessories packed in plastic bags, and the heavier motor and battery boxed and secured separately.
This is not a difficult build, but requires some planning. Consider your Rx and seek something very small. I used a Spektrum AR6000, but trimmed off all the plastic I could to save weight and to wedge it into the fuselage. Little dabs of hot glue here and there is all that is needed.
Begin by installing the JST connector to the ESC and then connecting the ESC to the motor. You can shorten the battery lead some to save weight, but the motor leads should remain the same. You will also have to test run the motor after making your solder joints to make sure it is turning in the correct direction before installation.
Servo screws are used to install the motor. The mount is installed and the motor aligns perfectly. Thread the motor leads and ESC under the firewall since there is enough room.
The prop hub is a little different than most in that you will glue the prop to the hub permanently. This glued group includes the hub, backing plate, prop holder and spinner. One spinner is pre-molded to clear the prop and is painted blue. The other is white, but requires some cutting.
This is of course optional, but it really does make things look good. If you are getting above 65 grams, this might be a consideration for removal. I painted mine for looks.The pilot will come up through the bottom of the cockpit and will glue to the backrest of the seat. Decals are provided for the cockpit, but if you use these you will need to carefully lift the canopy off. Mine was pretty tight, so rather that cause any damage I did not remove the canopy. A trap door closes under the pilot to seal the cockpit.
The wing has the ailerons molded in so take a minute to exercise the ailerons before installing the single wing servo. Theses linkages are sensitive to friction so avoid causing any other than that which is present. The linkages will center on a centered control arm installed in the center of the wing root, but not in a traditional manner. Make sure you have your servo centered before beginning this portion of the build.
The linkages need to cross in the middle of the servo and be joined with one central linkage that attaches to the servo arm. Make sure when you are making this join you provide about 1mm of wash out (up aileron on both wings) before you glue the linkage. Be very careful not to let any glue bleed into the servo. I suggest you take some petroleum jelly and seal the servo gear and arm so that if any bleeds it cannot stick.
The tail is completed and ready to go. You can install a rudder servo if you want, but keep an eye on the weight. I think you can add a few grams. A lightweight linkage and the control horn are provided.
Install the elevator servo on the sidewall of the fuselage on the starboard side. Use double stick tape to secure the servo. Install the battery mount up front behind the firewall. Take a minute to slide into place the Rx and the battery and see how close you are to balancing. All that is left is to install the bolt reinforcements to the wing and fuselage to attach the wing.
Completing the Alfa P-51D is all about CG and control setup. You have to get the CG spot on so take your time here. I actually took two dowel rods and mounted them to the work bench to set the plane on and check the CG. You can use your fingers, but this is not that accurate, and getting the CG accurate will greatly improve your flight performance.
This is a water based decal set that requires you to soak the decal for a few seconds and then slide them off the decal sheet onto the aircraft. Once set they will stick, but you can move them just a little. Be careful as they will tear.
I used my Spektrum DX6i and included dual rates with the prescribed setting at the high point, and I delimited the setting to half on the low rates. Start here as too much aileron movement and the P-51 will tip stall. Start with a little movement and increase to your comfort level. I also used some expo to soften the sticks.
As you work to get the CG correct, realize that this is a small plane, and because of the weight and the length, balancing is tough. A very slight movement of the battery, for example, will cause a huge change in the CG. I started with locating the RX towards the back and used the battery to get the balance point. There are variables here to consider with your choice of equipment, so get it right and take your time.
Make no doubt about it, this is a warbird. It will stall and really does not do a lot of flying once the power comes off. The glide slope is pretty shallow. The wing loading is very low, but it still flies like a warbird with stalls that happen quickly. Keep your speed up and power through the turns, and you will not have a problem.
Because this is for advanced flyers, be prepared for a quick plane that, once in the air, flies very well. Once it slows it wants to stop flying due to the fact little mass is available to create momentum forward. Get too slow, and it will stall. The P-51 is fun to fly, and it gets up and goes pretty well. The wind does play havoc on the plane so keep the winds below 5 mph, but otherwise this is great indoor flyer.
A sight hand launch is necessary, but be careful to toss it level to avoid a stall. Just let go with a gentle forward toss. Once you get the P-51 trimmed, the launches will become very easy. Landing is a power on process that really is like most warbirds I have flown. It just requires respect all the way to the end of runway.
Landings are where you'll probably incur any damage. I suggest using a smooth surface or the wing will grab the grass and try to wrench itself off the fuselage. Do this enough, and you will break the EPS foam.
The wingovers are realistic, and the rolls are nice and straight. Inverted fight can be accomplished, too. Things happen quickly so you have to pay attention to the flying. That is why this is for advanced flyers; pilots that know how to fly and can recognize flight attitudes.
No! But I highly recommend this for advance flyers.
I liked the build and the level of detail in the design. The P-51D is a beautiful plane to be enjoyed by those that can fly. Fight times are short, but because you have to stay with the plane, six minutes is enough. I think if you know how to fly a war bird, this will be a great addition to your hangar and one you can take to the park and fly. It is also a good value with all the micro components included.
|Feb 23, 2012, 02:41 PM|
Seems a shame to put 4g servos in this tiny plane. I bet an AS3X board and a light aileron servo would do wonders for this little plane!
|Feb 23, 2012, 03:58 PM|
A HK 415 and 2g servos would have made it almost 10g lighter. An XP7a would have saved another 4g... so it could be almost 14g lighter for about $30 in components.
The plane is beautiful, but $169 seems a little steep for foam and a HK 5g outrunner (and too heavy components).
|Feb 23, 2012, 09:36 PM|
Joined Nov 2000
yessss.. That's serious coin for a 16" span Toy airplane, which despite it being smaller is No better (actually less detailed and decidedly more fragile, not even being EPO foam but EPS ) than the Nitroplanes /Banana hobby 800mm ones which come with a TX .. ready to fly.. for a whopping $80!!
Methinks it portends the end for Alfa, admittedly after a good run, but it's clearly out of the race now.
|Feb 23, 2012, 10:15 PM|
|Feb 23, 2012, 10:43 PM|
Joined Oct 2000
I'm not sure from the photos- but there looks to be a bead on the leading edge. Several times you mentioned that the airplane has an unpleasant stall, and given the wing loading- which seems to be reasonable, I'm guessing that there might be an issue with the leading edge. At the risk of needing a little paint, you might want to make sure it's nice and smooth- no sharp edges. That might help tame the stall.
|Feb 24, 2012, 12:12 AM|
On some of my WWII models, I've reflexed both ailerons up just a little to give the wing some washout near the tips. That trick has calmed down the nasty stall on several of my birds.
|Feb 24, 2012, 06:37 AM|
Joined Nov 2005
Folks great comments. Just some rationale on the AR6000. It was light weight and compared to a brick seemed easier to place. I trimmed back a bunch of plastic to get it inside the fuselage and meet the CG. The servos are included with the P-51 so I used them. In the end I had my weight close enough. Stalls were quick even with some washout. Biggest thing I noticed was just how little control surface movement I needed. Keep it minimal even though the servos can produce more. Great catch on the front of the wing. That indeed could be breaking up the airflow and should be considered.
As for price, I see this as a complete package ARF with servos, ESC and the motor.
|Feb 24, 2012, 07:21 AM|
Joined Dec 2007
In the end I had my weight close enough. Stalls were quick even with some washout. .
I would have replaced the stock servos with something like this.
4g servos I use that on the rudder and elevator on my Alfa M. Albatros!
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