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P-2V Neptune Slurry Bomber


Active member
I may be getting super ambitious here, but I would really like to build a foamie P-2V Neptune plane. They were a staple in the sky through last year because Neptune Aviation is based out of Missoula, where I live. The real plane is the slowest flying plane I've ever seen, when they were out doing test flights, they just crawled along.
I did find some old balsa control line plans for the plane, I am going to see what I can do to use those as a reference to design a foam version. I'm having a tough time deciding on scale though. The wingspan is 100', I would like to do 12th scale but that is a massive plane. I think I will end up going about the size of the Guinea pig.
Jeff-Reynolds-4-2017.jpg IMG_E7005.JPG

Alright Guys, I ended up scaling the plane to match the prop size to a 10" prop. See final specs below. I attached V1.0 of my P-2V Plans here. It flies very well on a twin C-Power pack. 50% throttle runs nice and level, it even has a nice glide slope.

AUW W/ 2)1300mAh batteries: 2.23 lb/1015g
Wingspan: 57"
Length: 52"
CG: 2.6-2.9" Behind Leading Edge. Flown at 2.3"
Wing Area: 358 sqin
Tail Area: 77 sqin
Wing Loading (2D): 14 OZ/sqft
Wing Cubic Loading: 9.11

The plans currently don't have a bottom center section of the fuselage below the wing. I will update them once I come up with a plan for a set of bomb bay doors. I had concerns about getting the CG far enough forward and I planned on putting the batteries in front of the wing, but it turns out, the weight of the motors was enough to achieve the correct CG. I had to install the batteries at the back of the nacelles closer to the CG to not be too nose heavy.


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Active member
I'm off to a slow start, I really have no idea what I'm doing. Here's where I'm at so far.
I haven't quite figured out how the tapered outer wing profile is going to work.

A few more hours of work...
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Active member
I would try mounting the power pods sideways, that way you could form the nacelles to be a vertical oval like the real thing.
They should be big enough to give them that vertical shape, I will make some arced pieces and try to fit them in there. I'll install them on the second wing before I put the cowling on.

I need to take a trip out to the Missoula Airport, I cant find many good pictures of this plane, they just put one in front of our airport last year when they retired them from firefighting service.


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I have to make sure to get that curve out of the frame as I work my way back. I should have made sure to get the curves opposite directions. Im not sure why my foam board is so curved.


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Any tips on how big to make the ailerons? They are looking slightly undersized to me in my last post. I can extend them all the way to the wing tips, the wing crease intersects the aileron crease at the wing tip.


Toothpick glider kid
Any tips on how big to make the ailerons? They are looking slightly undersized to me in my last post. I can extend them all the way to the wing tips, the wing crease intersects the aileron crease at the wing tip.
I would do that, it's always better to be able to tame down the controls than to be needing more out of them.


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Now I just watched the Viggen review and now I want to redesign all of the curved parts. I’m really not happy with how the curves turned out. I think the blocky old school graphics look would be much nicer looking and easier to construct. And probably lighter.


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Well, the build is pretty much done. I think I am going to redesign the fuselage, It feels super heavy.
It weighs 1.2 lb as is with no electronics or servos. Then I have to figure out how I'm going to power it, I'm leaning towards twin C-pack.



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I have a power setup question for you guys. My build is pretty much complete except for electronics and power. I don't have a scale but I do have a balance.I have an FT Simple cub and a 150% FT Corsair. They both fly great on the B-Power pack and on the balance, they both weigh slightly more than my P2V, does this mean I should be able to buy a twin B-Power pack and it should fly fine or does the power not scale on a plane?
Actually, I would probably buy some 20A esc's because I have 4 motors off of a Phantom 3. Correct me if I'm wrong but it looks like the phantom 3 motor is basically the same as the B-Pack motor. It turns out phantoms turn into a very expensive rock when they turn off 200' above ground.


Active member
Well, I think I'm done with the octagon fuse design.

Reiterating my previous question, if this plane weighs less than two planes that fly well with a B power pack and each wing of this plane is a similar size to the total wing span of each of the other two planes, will a twin B power pack be enough power for it? Or should I step it up to a twin C pack? I would like to be able to carry some payload within the future bomb/slurry bay.


Wake up! Time to fly!
I would think that would depend on wing loading and over all drag if the weights are similar.

My guess would be try n see with what ya got if its in a reasonably close range for other setups.

Btw once you have this in the air move on to a p3 c update as several of us here were crew in some form or other.

Go Aircrew!!