Cormorant II

Pieliker96

Elite member
The description was excellent and the pictures were very clear.
1f917.svg
Thank you!


awesome! I might try this with my spare f pack motors, but I'm sure I won't use drooperons yet
If you do, post pictures!
 

Ron Dunn

New member
The beta plans have been released. They represent the initial plans plus corrections from the experience of building the first test vehicle, and come without a build guide. If you'd like to have a go with these, I'll help you along the way - although you could wait a month for the final plans and build video.
 

Battery800

Elite member
@Pieliker96 I have four questions:
Can I run this on something like a 3200 3s or 4000 3s and still work well?
Does the plane have a cargo door or a way to carry cargo
I’m worried about strength and durability, should I just go with regular flaps?
Are you going to scale it up to something like a guinea?
 

Pieliker96

Elite member
@Pieliker96 I have four questions:
Can I run this on something like a 3200 3s or 4000 3s and still work well?
Does the plane have a cargo door or a way to carry cargo
I’m worried about strength and durability, should I just go with regular flaps?
Are you going to scale it up to something like a guinea?

There's no reason why it couldn't carry a larger battery, though you'll likely have to move the battery tray further back in the fuselage to get it to balance proper and/or create a custom battery tray to accommodate. Of course, flight speed and performance will be reduced a little due to the increase in all-up weight.
There isn't a cargo door, though there is plenty of space in the fuselage under the wing. The extended battery tray may reduce some of that capacity, however.
Regular split flaps would work fine. For what it's worth I've found the fowlers to be surprisingly durable and easy to repair, though they take a good bit of effort over split flaps to build and get working.
I have had ideas to scale it up to a twin C-pack setup, though the main problem I've run into is prop clearance. With 6" props, the stock airframe can theoretically strike a wingtip without hitting a prop. So scaling up to a 9" prop gives a wingspan of 6.5 feet, which is rather unwieldy - the original small airframe's span is just 6" shy of the full size Guinea Pig's! Ifin I do a scaled up version it'll likely forego that prop clearance. Don't count on it though, that's one of the lowest things on my list to do currently.
 

Battery800

Elite member
There's no reason why it couldn't carry a larger battery, though you'll likely have to move the battery tray further back in the fuselage to get it to balance proper and/or create a custom battery tray to accommodate. Of course, flight speed and performance will be reduced a little due to the increase in all-up weight.
There isn't a cargo door, though there is plenty of space in the fuselage under the wing. The extended battery tray may reduce some of that capacity, however.
Regular split flaps would work fine. For what it's worth I've found the fowlers to be surprisingly durable and easy to repair, though they take a good bit of effort over split flaps to build and get working.
I have had ideas to scale it up to a twin C-pack setup, though the main problem I've run into is prop clearance. With 6" props, the stock airframe can theoretically strike a wingtip without hitting a prop. So scaling up to a 9" prop gives a wingspan of 6.5 feet, which is rather unwieldy - the original small airframe's span is just 6" shy of the full size Guinea Pig's! Ifin I do a scaled up version it'll likely forego that prop clearance. Don't count on it though, that's one of the lowest things on my list to do currently.
Really? I didn’t know this plane was so big compared to it and still ran on quad motors
 

Battery800

Elite member
oh and 3 more questions
are the extensions with clip necessary or can I just use normal extensions?
how are the dual rudders attached?
did you run it on 4s yet? I imagine it would be like a rocket
@Pieliker96
 
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Pieliker96

Elite member
oh and 3 more questions
are the extensions with clip necessary or can I just use normal extensions?
how are the dual rudders attached?
did you run it on 4s yet? I imagine it would be like a rocket
@Pieliker96
The clipped servo extensions aren't strictly necessary but give you the peace of mind that they have a lesser chance of detaching themselves in flight. If you're not planning on entirely detaching the wing for transport but just moving it a tad for changing the battery, there's enough slack in the lines that you can get away without ever disconnecting them.
The dual rudders attach to the tips of the horizontal stabilizer. Servo arms are embedded in their foam which is linked by two long pushrods secured with zip-ties to the single rudder servo. It's a bit jank but it works well enough. You can forego the rudders and yaw entirely with differential thrust if you'd like.
I haven't put mine on 4 cells due to concerns over blowing up the FT 20A ESCs, which I'm already pushing pretty hard with the 6x4.5 bullnose props. Even on 3 cells, it is quite a rocket, by my standards at least: Easy vertical and more level flight speed than I'll ever be able to use in a small park.
 

Battery800

Elite member
The clipped servo extensions aren't strictly necessary but give you the peace of mind that they have a lesser chance of detaching themselves in flight. If you're not planning on entirely detaching the wing for transport but just moving it a tad for changing the battery, there's enough slack in the lines that you can get away without ever disconnecting them.
The dual rudders attach to the tips of the horizontal stabilizer. Servo arms are embedded in their foam which is linked by two long pushrods secured with zip-ties to the single rudder servo. It's a bit jank but it works well enough. You can forego the rudders and yaw entirely with differential thrust if you'd like.
I haven't put mine on 4 cells due to concerns over blowing up the FT 20A ESCs, which I'm already pushing pretty hard with the 6x4.5 bullnose props. Even on 3 cells, it is quite a rocket, by my standards at least: Easy vertical and more level flight speed than I'll ever be able to use in a small park.
I think I can use the 4s, because I’m using the big ft ESCs (35a?) And using little bullet adapters from rc planet
image.jpg
 

Pieliker96

Elite member
do think it would be necessary to have a win reinforcement?
@Pieliker96
I presume this means "Wing reinforcement"
My spar is entirely foam. I haven't intentionally tried to pull the wings off yet but haven't had a problem doing all sorts of aerobatics. If you're going to really push it hard - carrying heavy payloads, hard pulls at high speed, running on 4 cell - it wouldn't hurt to add some more foam or some wood to the spar.
For reference, the main spar has four vertical strips of foam at the root, dropping to two further out and then to zero where the internal wing space ends. It's twice as much as a traditional FT spar at the root and similar for the rest of the wing.
 

Battery800

Elite member
@Pieliker96 sorry to bother you so much, but on the outer wing skin, the middle cut appears to be a cut through with a little park on the inboard side as a score. Is this correct? Also, what is the dimensions of the battery box? I want to fit a 4000 mah Lipo in.
 

Pieliker96

Elite member
@Pieliker96 sorry to bother you so much, but on the outer wing skin, the middle cut appears to be a cut through with a little park on the inboard side as a score. Is this correct? Also, what is the dimensions of the battery box? I want to fit a 4000 mah Lipo in.

The central leading edge fold should be a score cut, not a cut-through - there were some overlapping lines that showed differently in inkscape versus the PDF export. I'll update the plans accordingly.

The battery tray is sized for a standard 2250mah 3 cell of 1.25" width (and about 0.9" height, 4" length). If your pack is wider, you'll want to change the spacing between cutouts in F1 (Battery Tray) and the width of the rectangular cutout in F7 (Fuselage Former Lower). Depending on where the CG ends up you may find yourself moving the battery tray aft of F7, possibly resting on G3 (Gear Former 1/2) or cutting it in half and putting it on both sides of F7. The height from the battery tray to the bottom of the wing (vertical height constraint) is at least 2.25", and the length of the pack is not a factor.

And it's hardly a bother, don't worry about it - And thank you for taking the time to try out one of my designs! I appreciate it!
 
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