Hi, I am making an SST.

[Joseph Kerman]

So, yeah. Title.

But the way I see it, I can't make an SST using those engines without having a small plane or a crapton of engines. So, if you have suggestions on how to make a supercruising SST, I am open for any solutions.

[steuben]

Supersonic  is only 350m/s.

It's doable on a light plane with three or four junos, if you're careful.... I think. I'm going to have to double check.

How much are you trying to carry? What techs do you have available?

[Aegolius13]

Which engines are you using? Every engine is theoretically capable of supercruising, but some have trouble breaking through transonic drag before their thrust really kicks in.  

You could try the panther on afterburning mode,  then switch to dry once you've reached desired speed. It's a great engine for general atmospheric stuff. 

What is your ascent profile?  It's often good to climb subsonic to at least 5km, then level off or even slightly dive to get supersonic. 

Your plane might also have some drag issues.   Pix?

[GoSlash27]

If you use the right engine, pay close attention to drag, and fly the correct profile, you can attain hypersonic speeds with as little as .35 thrust-to-weight.

You don't have to load it down with a bunch of engines, it just needs to be clean.

*You have a lot of flexibility in wing loading, so don't be afraid to add wings. I like to use one set of shuttle wings for each pair of engines.
*Keep the intakes to a minimum. One shock cone + a precooler is adequate to feed as many as 4 engines.
*Build the plane as drag-free as possible. Smooth transitions, no open nodes, no drag- inducing junk on the surface.
*Build some incidence in the wings so that the nose is pointed directly at the prograde around Mach 1- Mach 1.6. This will help you slip through the sound barrier with a minimum of parasitic drag.
* When possible, build long instead of wide. The less frontal area, the better.

Once you get past 360 m/sec, hang on to your hat. Thrust goes through the roof and drag falls away.

 

Best,
-Slashy

Edited December 15, 2017 by GoSlash27

[AeroGav]

I did supercruise on this design. 

https://kerbalx.com/AeroGav/Screechcraft-Starship-SST

 It will be much easier if your SST has a mk1 fuselage as they have low drag.   Mk2 is the hardest as drag quite bad.   Mk3 do-able but part count could get silly - you'll need a lot of wing and engine parts to get it working.

2.5m are actually only slightly more drag than mk1 parts,  you could make an SST  based on Hitchhiker containers with a "cockpit" of a mk2 capsule and a shock cone on the front,  and a mk2.5 tricoupler at the back for mounting engines.    However, when you're not in zero g, that cabin layout doesn't look very comfortable.

See this post for details on how slick 2.5m parts can be...

 

 

Edited December 15, 2017 by AeroGav

[GoSlash27]

An example of "low thrust/ low drag" using Mk.3 parts:

This design used only 4 engines, yet was able to get hypersonic in air breathing mode despite the fact that it weighed 125t at takeoff.

Best,
-Slashy

[bewing]

For going supersonic, drag is definitely the enemy. As said above, any engine except the Goliath can get you supersonic. You may need about 3 junos. But one of the others: wheesley, panther, whiplash, or rapier will do it. As said above, for supercruise, use MK1 parts. Build light. Take less fuel. Don't go crazy on the wings. The fancier you make the plane, the less likely it will be able to go supersonic.

 

[foamyesque]

Well I mean people say that but