Cormorant II

[Battery800]

If I were to add a piece of reinforcement to the fuselage, where would be most effective?

 

[Pieliker96]

Whoops. I mean 1300 grams since I thought I put two motors into the calculator but I didn’t but 1300 grams of thrust each is as hard as I can possibly push them. On the calculator you can select the cooling of the motor to good, medium, excellent, poor, very poor, and I think this plane has good motor cooling right?

Yeah, the motors are decently well exposed to the airstream. That thing is going to be a rocket ship! Be prepared to fly it fast, the wing loading here will be significantly higher than a usual config.

If I were to add a piece of reinforcement to the fuselage, where would be most effective?

Make sure the battery tray is really in there and able to support the extra weight. Do the same with the landing gear - you may want to double up the strips on the main gear axles and beef up the nose gear structure (thicker wire, reinforcement from the top of the gear structure to the sides/top of the front fuselage, etc.) The area where wing mount skewers attach to the fuselage could be reinforced (Add wood/plastic doublers if you haven't already), and you'll probably want to use either more or stronger rubber bands to attach the wing to the fuselage.

 

[Battery800]

Yeah, the motors are decently well exposed to the airstream. That thing is going to be a rocket ship! Be prepared to fly it fast, the wing loading here will be significantly higher than a usual config.



Make sure the battery tray is really in there and able to support the extra weight. Do the same with the landing gear - you may want to double up the strips on the main gear axles and beef up the nose gear structure (thicker wire, reinforcement from the top of the gear structure to the sides/top of the front fuselage, etc.) The area where wing mount skewers attach to the fuselage could be reinforced (Add wood/plastic doublers if you haven't already), and you'll probably want to use either more or stronger rubber bands to attach the wing to the fuselage.

Yeah, I have 1.5mm wire for the nose wheel and am planning to use pain sticks on the main axles. Also, I added a third layer of paint stick doubler running to the servo on the forward spar, so this thing will be built like a tank. I’m almost done the wing right now and just need to mount the flaps. This build is a lot simpler than I thought it was going to be!

 

[Battery800]

3s with my current config is about 1500 grams of thrust total, and 4s is about 2750 gams thrust

 

[Battery800]

@Pieliker96 so I have a question about the wiring. The estimate right now is that I will be pushing around 60 amps with my two motors, and that should be fine when they have a 35 amp ESC each. On the ESC that I am using, it says that it has a 3 amp 5 volt bec. Is that separate from the 35 amps or included since I don’t want to get past 30 amps.

 

[Pieliker96]

@Pieliker96 so I have a question about the wiring. The estimate right now is that I will be pushing around 60 amps with my two motors, and that should be fine when they have a 35 amp ESC each. On the ESC that I am using, it says that it has a 3 amp 5 volt bec. Is that separate from the 35 amps or included since I don’t want to get past 30 amps.

The 35A is for the motor independent of the BEC.

 

[Battery800]

So uhh where exactly is the battery tray supposed to go? Above the axles, between the nose wheel and the main landing gear or somewhere else

 

[Battery800]

Also I’m nearing the end, although it turns out that I got steel rods that were too short, so I’ll have to get longer ones.

 

[Pieliker96]

So uhh where exactly is the battery tray supposed to go? Above the axles, between the nose wheel and the main landing gear or somewhere else

With a 2250, it'll go in front of former F7 - since you're running a larger battery, wait until you've got the whole thing constructed, find where it needs to be to balance properly, then put the tray in an appropriate position. It'll likely end up on top of formers G3 and/or butted up against the back of former F7.

 

[Battery800]

Everything is done but the hatch, which I am About to do. What does the cavity do? @Pieliker96 can you bring some magnets for me? I don’t have any

 

[Battery800]

Ok so I’m done building and I have 3 issues:
1. The hatch keeps lifting from the top of the wing so there’s a gap.
2. The rear of the hatch is more curved than the surface it’s touching, so it looks weird.
3. I don’t know how the rubber bands go, do the regular small ones work?

 

[Pieliker96]

Everything is done but the hatch, which I am About to do. What does the cavity do? @Pieliker96 can you bring some magnets for me? I don’t have any

1 . The cavity is to allow the peak of the main wing some clearance so it doesn't hit.
Unfortunately I'm all out of magnets, tape should do well.

Ok so I’m done building and I have 3 issues:
1. The hatch keeps lifting from the top of the wing so there’s a gap.
2. The rear of the hatch is more curved than the surface it’s touching, so it looks weird.
3. I don’t know how the rubber bands go, do the regular small ones work?

2. Do your best to get the hatch to fit proper. It's a quite finicky part that took the most revisions out of any other - if I understand it properly, the top curvature is too pronounced relative to the fuselage, leaving a step in the transition. This can be remedied by bringing the side plates of the fuselage slightly closer in that area which will increase the curvature of the top part - I'd do this by gluing a slightly undersize foam cross-member in the area where needed.
3. Potentially yes - I tied multiple together to get the desired length. They go from the front to the rear skewer across the wing without crossing over in the center.

 

[Battery800]

1 . The cavity is to allow the peak of the main wing some clearance so it doesn't hit.
Unfortunately I'm all out of magnets, tape should do well.



2. Do your best to get the hatch to fit proper. It's a quite finicky part that took the most revisions out of any other - if I understand it properly, the top curvature is too pronounced relative to the fuselage, leaving a step in the transition. This can be remedied by bringing the side plates of the fuselage slightly closer in that area which will increase the curvature of the top part - I'd do this by gluing a slightly undersize foam cross-member in the area where needed.
3. Potentially yes - I tied multiple together to get the desired length. They go from the front to the rear skewer across the wing without crossing over in the center.

I might try to find some bigger rubber bands at ff. Are you bringing you cormorant and the oblique wing plane?

 

[Pieliker96]

I might try to find some bigger rubber bands at ff. Are you bringing you cormorant and the oblique wing plane?

yep!

 

[Battery800]

I really like the look of this plane and I think it does need a bigger cousin. Drawing from the C-47, I think a 72” inch running on c pack (probably 8x6x3 props) or the same motors and nacelles, just with four, would be nice. I do not know if four 2205 motors would be enough thrust though

 

[Battery800]

Actually, I have begun Looking into other motors @Pieliker96 one way to solve the prop clearance problem is to use something like a sunnysky 2814 1250kv motor. Almost 3kg thrust on 4s and 9x6, so you could probably scale it to 175%

 

[Pieliker96]

I think the marking on the drooperons is a mistake, I think it said to make a cavity instead of bevel

Bevel is correct - it's effectively a standard control surface hinge using the top wing skin.

 

[Battery800]

Bevel is correct - it's effectively a standard control surface hinge using the top wing skin.

Whoops! It’s just hard to see because my printer is having issues printing in magenta