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P-2V Neptune Slurry Bomber

Tjhochha

Active member
#1
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.

Specs:
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.
 

Attachments

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Tjhochha

Active member
#4
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.
CAD 1.JPG


A few more hours of work...
CAD 2.JPG
 
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Tjhochha

Active member
#9
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.
 

Tjhochha

Active member
#10
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.
555087A6-0999-41CF-9533-1DF23BE6C3FB.jpeg
 

Tjhochha

Active member
#11
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.
 

foamtest

Toothpick glider kid
#12
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.
 

Tjhochha

Active member
#16
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.
 

Tjhochha

Active member
#17
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.

8E791860-16A7-48E8-BBE3-40120E3572BD.jpeg
 

Tjhochha

Active member
#18
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.
 

Tjhochha

Active member
#19
Well, I think I'm done with the octagon fuse design.
1541046697325.png


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.
 

PsyBorg

Wake up! Time to fly!
#20
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!!