Why can't this plane achieve lift?

[What Zitt Tooya]

Don't be fooled by my hours in KSP, most of it is spent in the VAB. I'm terrible with planes.

I've tried moving the wings forward and backwards of the CoM but I still can't seem to get lift.

https://steamcommunity.com/sharedfiles/filedetails/?id=1756515755

[Clarence Boddicker]

Looks good to me. How far do you get off the ground? The controls set up correctly? You're saying you just drive straight off the runway into a mountain?

[Sgt. Frosties]

Try more wing surfaces or increase your speed

[F'lar]

Your main gear looks too far aft. They should be near or a little aft of CoG. You should be able to pivot at that point and the gear that far back won't let you. I'm not sure what you're trying to do with that cone in the rear either. Just looks like something that will destroy itself when you rotate for takeoff.

[MadArkael]

your rear landing gear are a long ways behind your center of mass, this wouldnt be too much of an issue if your control surfaces were behind the wheels as well, but from what I can see, your control surfaces which would help bring your front up by acting like a lever pushing down on the opposite side of the rear wheels, is unable to at all because the wheels are behind the surfaces.

[Sgt. Frosties]

Try and have your rear landing gear just behind it ontop of your center of mass

[F'lar]

Here's one of my early planes...look where the gear is in relation to the CoG (btw, what I think of as Center of Gravity as a pilot is CoM in the game).

https://steamcommunity.com/sharedfiles/filedetails/?id=1756539354

She flies surprisingly well and is pretty nimble even if she isn't that fast.

[Sgt. Frosties]

Interesting I generally prefer to have my centre of lift in front rather then behind

[F'lar]

Originally posted by Sgt. Frosties:

Interesting I generally prefer to have my centre of lift in front rather then behind

I've found that having in front can make a plane act squirrely. Until I moved CoL aft of CoM, I couldn't get my SSTO into orbit.

https://steamcommunity.com/sharedfiles/filedetails/?id=1640213502

[Purplefairy22]

Originally posted by BOT Harvey:

https://steamcommunity.com/sharedfiles/filedetails/?id=1756515755

Now, its hard to see properly but have you got any control surfaces (Elevons) attacted to those wings?
ain't gonna fly without those!.

Also you've got main wing but where is the smaller wings for pitch and balance?

[Hotaka]

Originally posted by Purplefairy22:

Originally posted by BOT Harvey:

https://steamcommunity.com/sharedfiles/filedetails/?id=1756515755

Now, its hard to see properly but have you got any control surfaces (Elevons) attacted to those wings?
ain't gonna fly without those!.

Also you've got main wing but where is the smaller wings for pitch and balance?

It looks like it's missing those, which means he definitely will not get enough lift to leave the ground.

[F'lar]

Originally posted by Purplefairy22:

Originally posted by BOT Harvey:

https://steamcommunity.com/sharedfiles/filedetails/?id=1756515755

Now, its hard to see properly but have you got any control surfaces (Elevons) attacted to those wings?
ain't gonna fly without those!.

Also you've got main wing but where is the smaller wings for pitch and balance?

It looks like he does have control surfaces on the wings - look at the shadow on the floor. If by 'small wings' you mean a canard it shouldn't be necessary.

[Manwith Noname]

Originally posted by BOT Harvey:

Why can't this plane achieve lift?

It might achieve lift, it might not have great pitch authority.

If you mean you cannot pitch very well, add some control surfaces at the very rear of the craft. As others have mentioned, move the rear landing gear closer to the CoM to aid take off rotate.

If it is capable of pitching but just nose dives off the end of the runway, you need more speed, more lifting surface area, or to put it on a diet.

[GRAY]

Look at the weight. It's 8 tons! Such a wings can generate enough lift force for 3-4 tons craft.
You don't need so much fuel, 15000m/s is enough for a world-around flight.
PS and move control surfaces as far as possible from the mass center.

[Scandalf]

My plane on a new session is quite similar to yours. Similar shape and ~6 tons.
It ain't perfect but it flies.

People have already given good advices.

1. At take off, your speed is minimal, so is the lift generated.

Things that can help :
- Add more control surfaces.
- Rotate the craft, by placing the front landing rear lower than the rear landing gear.
- Rotate some of the wings (ie don't place them perfectly horizontally).

2. Don't put your rear landing gear too far back from CoM. Otherwise your craft won't be able to rotate (around your CoM) and the nose will never go upward.

3. Don't build too far back from CoM, otherwise, when the craft will lift its nose, the rear will touch the runway. Bad thing might happen then.

4. Add more trust, in order to reach the necessary speed that generate enough lift for your craft.

5. Be aware that if you add more of everything, you'll end with the same problems,but in another scale.

In my case, a strong control surface on the front, coupled to the lower front landing gear allow me to have the rear landing gear far back. It's all about balance.
(There are Delta winglet as control surface on the big wings that you can't see properly).

https://steamcommunity.com/sharedfiles/filedetails/?id=1757408336

[Hotaka]

As others have suggested, give it some tail fins so you have more control. Ones that have control rudders. One top, center, and two symmetrical close to the one at the top but angled out.