Lift Rockets on a Sea Plane? Relay Antennae Drag?

[Zosma Procyon]

Last night I went from a feeling of triumph that I had, after a week of experimenting, arrived at a seaplane base design that could safely touchdown and lift off from the oceans of Laythe; to the feeling of utter failure after a last minute (and from my thought processes at the time purely a formality) atmospheric insertion test on Laythe in my testing sandbox. It survived a 2400 m/s unpowered insertion just fine, but when I landed in the ocean I could not get it back in the air. My extensive testing on Kerbin did not account for the lower atmospheric pressure at sea level on Laythe. The plane was only able to reach about 60% of the liftoff speed due to reduced jet engine thrust, and in the reduced atmosphere it did not have enough lift. I've already planned a more extensive testing regime, but it occurs to me I might be able to make my original design that I a quite proud of work if I simply add rocket engines to the belly and use them to lift it out of the water. They'd be action grouped to turn off with the press of a button. Ideally they wouldn't be staged, but we don't have that option in game yet. Has anyone else ever used rockets to grant a jet aircraft vtol capability? Any pointers?

Also, do the relay antenna parts generate a noticeable amount of drag? My bases always have to include at least 3 antennas: One high gain antenna per science lab (at least 2), and one relay antenna. But because the base i have to redesign is also a plane, I need to know if drag from the relay antenna has to be accounted for.

[bewing]

Yes, plenty of people make vtol spaceplanes or rato ones. Generally by sticking aerospikes on the bottom.

However, I was able to get my version of your base off the water at Laythe with a full load of fuel. So it is theoretically doable -- except it didn't have a relay antenna on it. I can stick a medium-sized antenna in a fairing, though.

And yes, relay antennas are enormous, and have a lot of drag. Depending on how huge and draggy your base already is, it may not make a noticeable difference, though. You'd probably be better off putting a tiny relay sat in orbit before you take this base down to the surface.

 

 

Edited September 25, 2018 by bewing

[Zosma Procyon]

20 hours ago, bewing said:

Yes, plenty of people make vtol spaceplanes or rato ones. Generally by sticking aerospikes on the bottom.

However, I was able to get my version of your base off the water at Laythe with a full load of fuel. So it is theoretically doable -- except it didn't have a relay antenna on it. I can stick a medium-sized antenna in a fairing, though.

And yes, relay antennas are enormous, and have a lot of drag. Depending on how huge and draggy your base already is, it may not make a noticeable difference, though. You'd probably be better off putting a tiny relay sat in orbit before you take this base down to the surface.

 

 

I actually have a few relay sats in orbit of Laythe, and all the other Joolian moons, already. Anyway I've built a version of the base with a larger wing and two more engines, and tested it with the 60% thrust I can expect in Laythe's lighter atmosphere. It seems promising, more so than the previous heartbreaking failure. A few more changes and it should be ready for a Laythe test. And i've reshaped the plane to put the relay antenna in fully in the shadow of the wider parts of the fuselage. Keeping a relay antenna on the thing is really more about principle than need. Anyway I like this version so much that if it fails to lift off Laythe's ocean, I'll probably add aerosppikes to its belly and show gravity who's the boss.