[1.12.5] Bluedog Design Bureau - Stockalike Saturn, Apollo, and more! (v1.14.0 "металл" 30/Sep/2024)

[Richmountain112]

5 hours ago, Pappystein said:

While it doesn't fly great in KSP Stock aero, it does fly.   I haven't put time into harmonizing the controls yet to fine tune it.     But also, the X-15 is TOO HEAVY to take off from the runway un-assisted for how Little the wings are.  (Those wings are meant to keep it aloft at Mach 5, not provide enough lift at 300m/s to fly up and away in the soup that is air density at the runway.    An Empty X-15 has a glide ratio of something like 4:1 meaning with no fuel for every meter you fall, you are 4 meters forward...  That is lower than just about any other high performance aircraft.   The BEST Glide ratios for some high performance aircraft: 

• F-104 is quoted as having a Glide ratio of 10:1 at high speed and "much lower" at low speeds
• F-16 is 7.8:1 ideal speed
• My next Automobile (The F-14 Tomcat) has a Glide ratio of 12.2:1 at ideal speed (which is much closer to landing speed than either the F-16 or F-104)

Remember, X-15 was meant to be dropped from the bomb Bay of the B-36 Bomber and then updated to drop from the Wing of a B-52 Bomber.  It is a Parasite aircraft, meaning it needs another craft to fly it off the ground.    If you want to launch it on a rocket, you need BIG wings on the Rocket or the rocket will "Spin out"

So that is why it spins around and crashes into the runway (one time I got it on the SPH instead) instead of flying despite having a starting TWR of approximately 1.06 at sea level, as reported by KER. Not even a disposable kickstand could get it to take off (granted, the kickstand wasn't a rocket sled and I used the stretched variant so maybe a rocket sled could get it to take off?)

Edited Friday at 11:17 PM by Richmountain112

[DaveyJ576]

16 hours ago, Richmountain112 said:

So that is why it spins around and crashes into the runway (one time I got it on the SPH instead) instead of flying despite having a starting TWR of approximately 1.06 at sea level, as reported by KER. Not even a disposable kickstand could get it to take off (granted, the kickstand wasn't a rocket sled and I used the stretched variant so maybe a rocket sled could get it to take off?)

Everything that Pappystein said applies, but if you don’t already have it I highly recommend the mod Atmosphere Autopilot. I use it and the X-15 flies well, as long as you meet the conditions that Pappystein laid out. AA makes the X-15 more responsive and controllable. It also works very well with the X-20 Dynasoar “Moroz” mod. 

[Pappystein]

On 2/28/2025 at 6:16 PM, Richmountain112 said:

So that is why it spins around and crashes into the runway (one time I got it on the SPH instead) instead of flying despite having a starting TWR of approximately 1.06 at sea level, as reported by KER. Not even a disposable kickstand could get it to take off (granted, the kickstand wasn't a rocket sled and I used the stretched variant so maybe a rocket sled could get it to take off?)

Sorry I forgot to mention a key fact in the X-15...

The Landing gear is designed to basically PREVENT it from going nose high on the ground.  The rear legs are soo far behind the COM that it is impossible (IRL) to rotate the air-frame to get a positive AOA on the wings too fly up from the ground (that is a safety feature.)  add their short length and you have a plane designed to stick to the ground once you have it there.

But yes, the Wings are too small.  The Delta wings have a COL too far back and the controls are frigidity meaning it is too easy to get roll reversals etc.     I set up a ZeLL launcher for the X-15 when it first became available to test...  And it worked... ONLY if it, the ZeLL booster had fins on it aligned with intended direction of flight.    Looked weird having a giant SRM aligned through the COM with fins pointed in X-15s direction of flight... but it got the X-15 up to about 100m before jettisoning and the X-15 flew fine from there.

ZeLL = Zero Length Launcher:

Yes, the aircraft in both of those pictures are piloted and in both cases they have a takeoff run length in less than 15 feet (the distance the rocket travels in its cradle)