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Nested VTOLS Challenge?

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I have been playing with VTOLs recently, and have made some progress, but I'm still working on a system to carry a small VTOL in, deploy it from, and recover to, a larger VTOL. The larger being the transport for the smaller. Think luxury yacht with deployable Jet ski. It should ultimately allow me to fly anywhere (on Kerbin), land almost anywhere, and deploy the sub-craft to visit the local science waypoints (Career mode style).


This set me wondering just how far it could be taken. How many nested VTOLs could be deployed from a VTOL?


By nested, I mean a VTOL inside a VTOL inside a VTOL. A typical entry would take off from KSC, fly a straight course until fuel forces a landing, where the sub-VTOL is deployed, and it flies along the same course, until it is forced to land, then it deploys it's sub-VTOL, etc.


I'm thinking there should be a scoring system based upon total horizontal distance covered (D) and number of VTOLs deployed (N), favouring the VTOL number. Perhaps D*N or D*(N*2), even D*(N^2).


Draft rules:


  • Each VTOL will be piloted. (It will have its own command seat, and must be flown from there).
  • Each VTOL will take off vertically, fly horizontally for some distance and land undamaged, vertically, under power before that leg is counted.
  • A leg ends when a flag is planted.
  • No rockets.
  • No RTG's or solar panels.
  • No decoupling parts, except the sub-VTOL.
  • No major clipping. (Cheesing extra fuel or engines or fully clipped aerodynamic parts, for example.)
  • RCS and/or RW's ok.
  • Fuel transfer ok.
  • No facility for re-nesting (recovery of sub-vtol) needs to be provided for.
  • Both DLCs allowed. Only passive Mods allowed. (Telemetry and such, no part or performance Mods.)


What do you think? Could this be an appropriate challenge for this topic?



Edited by boriz
Draft rules edited to reflect helpful suggetion by sevenperforce.
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On 4/22/2022 at 6:43 PM, chadgaskerman said:

So what you're telling me is that you want an airborne aircraft carrier?

I built something like that two years ago. It was not VTOL, but rather a spaceplane-carried spaceplane. 



  • The Lazybird dropping off its cargo, a three-man interplanetary mining-capable spaceplane, after achieving LKO.


No more stopping at Minmus to refuel. After the main spaceplane is dropped off in LKO, the unmanned carrier flies back to the KSC.




The craft file and usage instructions can be found here: https://kerbalx.com/Mars-Bound_Hokie/Lazybird


It took me countless hours and prototypes to finally get a prototype that works. So, in a way, although not VTOL, I made an airborne aircraft carrier.

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What you should do is score based on the distance covered by each successive VTOL, but add a multiplier for each successive stage.

So if you have a three-stage nested VTOL, then the first stage score is the distance covered by that stage, and then the second stage score is 2*distance covered by that stage, and the third stage score is 3*distance covered by that stage.

Even that might not reward successive stages enough, so you could do 1x, 2x, 4x, 8x, 16x... so that each successive stage receives a boost which is the square of the boost of the preceding stage.

Do the VTOLs need to be able to re-nest inside their parent vehicle, or can they decouple permanently?

Assuming a re-nesting capability requirement, I've got a single-Kerballed contra-prop-based VTOL aircraft (burning biprop with fuel cells for electricity) that pulls 58.3 m/s in surface velocity with 5324 seconds of flight time, or a range of 310 km.

I think I might be able to increase speed in level flight by giving it wings, but I haven't been able to make it perform well yet, and I fear it would make it too bulky to fit in a Matryosha  system.

It fits inside the 1.25-meter structural tube (with a hinge-based lift) of an accursed torpedo-shaped VTOL plane with Juno-based tiltwings that can pull at least 127 m/s in forward flight with a flight time of 2560 seconds (although I'm sure I could increase it by adding more LF; it has a generous liftoff T/W ratio of 1.11) for a range of 325 km. Depending on how the scoring is set up, I might benefit from adding a Wheesley or Panther engine to the back end to increase horizontal flight speed.

The "torpedo" fits snugly (with re-nesting capability) inside a Mk3 cargo bay, although I haven't yet built a VTOL plane around that. I might be able to make it small enough to fit inside a 5-meter fairing but that's a tall order.

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Draft rules updated. Thank you sevenperforce. I like the scoring idea too, though before a final system is agreed upon, I think some balance testing should take place. Might change the name to 'Matryoshka challenge'.


Currently, I'm up to two stages, with a third in the works. I think this challenge might end up with some massive first stages that don't fly very far, but boost the score for successive stages.

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