IncorrectCOL on heat shield magic wing crafts?

[jounce]

Is having problems with COL stuff

https://kerbalx.com/jounce/dragless+magic-wing-test

Can someone pls tell me what's wrong with the COL?

Currently the craft accelerates to some speed,takes off,then accelerates to ~220 m/s,then flips over because some parts are functioning as lifting bodies when I don't want them to.

(actually i was asking a different problem about it not being able to take off,thus the col relation,but then i found out that mechjeb sas fixes it)

I think that the culprit is the aerospike not actually being shielded.Testing...

dang its the engine plate

 

[jounce]

ok now its able to fly for a bit

but now there are some new problems

1) it does not turn its velocity when itsself turns

2) it still has a little bit of drag and i dont have any idea why

3) this craft sometimes spontaineously pitches up and sometimes its exerting a torque larger than what the reaction wheel can do

4) idk how to make control surfaces with heat shields

5) the controls just don't feel like a normal aircraft

[jounce]

ok now i can harness it a little bit,and it seems that the heat shields work best when angled at a specific angle relative to prograde,and they generate a lift force in a direction only relavent to prograde

@Nazalassa idea?

heat shields seem to generate aero force and lift in the same direction,and that direction is not relavent to where the craft is pointing at,and the magnitude seems to be the dot product of the prograde vector and a vector which is the heat shield's direction rotated by some amount

[jounce]

also this craft crashes immidiately when the reaction wheel runs out of power lol

[Nazalassa]

On 3/30/2024 at 5:02 AM, jounce said:

@Nazalassa idea?

The heat shields have to be angled 45^o forwards from the downwards position. That is, the curved part should be facing front-down and the rear part should be facing rear-up.

Dragless planes are quite different from regular ones, which use drag to turn. Thus it is normal that a dragless craft turns differently, if at all. If you want more regular-plane-like controls, consider adding a vertical control surface, like an elevon, and a horizontal one, somewhere where they are not shielded. Then you can use them like normal plane control surfaces.

[jounce]

3 hours ago, Nazalassa said:

The heat shields have to be angled 45^o forwards from the downwards position. That is, the curved part should be facing front-down and the rear part should be facing rear-up.

Dragless planes are quite different from regular ones, which use drag to turn. Thus it is normal that a dragless craft turns differently, if at all. If you want more regular-plane-like controls, consider adding a vertical control surface, like an elevon, and a horizontal one, somewhere where they are not shielded. Then you can use them like normal plane control surfaces.

• Okay  I have noticed this because I watched stratzenblitz75's video on heat shield wings,but I have not rotated the heat shields exactly 45 degrees.Will try that tomorrow!
• Ohhhh!I thought that they used lift to turn,since drag and lift face about the same direction when I do a pitch turn.(I don't do yaw turns unless I need quick,small adjustments because large yaw turns make the plane not face approximately prograde which is what i thought what a well-designed plane flying controlablly should not do.(they will only get velocity aiming to the sides,and they won't rotate by themselves so that the nose points to where they are flying to now,and planes are designed to point where they are flying to,otherwise the control surfaces aren't doing what they are designed to do))Anyways,I'll stick with using lift to turn,because drag in a dragless craft doesn't fit.I will try to angle the heat shields so that the part in front of the COM gets more lift that the part behind the COM....Or actually,the craft is already doing that,and I can add a piston to push and pull the wing forwards or backwards.That will be my pitch control.Yaw control and roll control=reaction wheels,which I need to make sure to power using RTGs.
• I have still not solved the problem of the mysterious ~1kn of drag.Where do you think it is?I don't see where the red drag arrow is.Maybe I should try to accelerate it to like 2000m/s at sea level to see where the drag is coming from  (half-joking)

Airbreathing engines don't work draglessly(intakes) and nervs and dawns work poorly in sea level,so my only option is the inefficient lf/ox engines.So I need the craft to be completely dragless.

Okay!That's the plan.I'll correctly angle the heat shields,add a piston between the rear nose cone and the heat shields for pitch control,try to identify and fix the weird drag problem,and try to fly it!I'll do it tomorrow.

[Nazalassa]

1 hour ago, jounce said:

I thought that they used lift to turn

Well, they may as well use both. But the point is, if it's shielded, it isn't taken in account into aero calculations, which means it will have neither one nor the other. No drag, no lift. The elevons should just not be shielded, and they'll work fine.

[jounce]

13 hours ago, Nazalassa said:

Well, they may as well use both. But the point is, if it's shielded, it isn't taken in account into aero calculations, which means it will have neither one nor the other. No drag, no lift. The elevons should just not be shielded, and they'll work fine.

That's why I am using magic wings.They don't have drag.

[Nazalassa]

4 hours ago, jounce said:

That's why I am using magic wings.

No, they do. If they had no drag, they would have no lift. However, heat shields have a damn huge lift-to-drag ratio, meaning they produce a lot of lift and very little drag. If you are only moniroting your drag with the red arrows from aero forces overlay, then it's likely that you did not see the drag from the heat shields. I suggest, if you did not do that yet, that you go into the debug menu (alt-F12), section 'physics', then 'aero', and enable 'show aero info in part menu' or whatever this option is called. Then right-click on one of the heat shields. You should see how much drag it generates, and possibly how much lift. If you need further help, it would be good to add a screenshot of the craft with the part action window open..

[jounce]

1 hour ago, Nazalassa said:

No, they do. If they had no drag, they would have no lift. However, heat shields have a damn huge lift-to-drag ratio, meaning they produce a lot of lift and very little drag. If you are only moniroting your drag with the red arrows from aero forces overlay, then it's likely that you did not see the drag from the heat shields. I suggest, if you did not do that yet, that you go into the debug menu (alt-F12), section 'physics', then 'aero', and enable 'show aero info in part menu' or whatever this option is called. Then right-click on one of the heat shields. You should see how much drag it generates, and possibly how much lift. If you need further help, it would be good to add a screenshot of the craft with the part action window open..

I think that they don't have drag if I cover two out of three nodes?I'll test that.

 

Edit:They have drag,and that is where the drag reading is coming from.Node covering only covers the two surfaces,not the sides.They still have got an excellent LDR though!The flag wings had no drag though,because they have no sides that don't have nodes.But now there are no flag wings.

Edited April 1 by jounce