Unequal air distribution

[Mars-Bound Hokie]

Hello. I built this new probe core-equipped jet that could carry up to six kerbals at a time and land anywhere. It's equipped with two J-X4 "Whiplash" Turbo Ramjet Engines for maximum speed and a couple of batteries to keep it running when the engines are out; a single XM-G50 Radial Air Intake on the top gives air to both engines. Below is a picture of the B-5 Badger on the runway.

• Check out the final entry in "The Eelootians," to see a report of its performance.

 

However, during flight, I notice that Engine Two (the engine on the right side) frequently flames out. I know it may have something to do with the air intake not delivering enough oxygen to mix with the fuel, but I'm confused as to why that engine specifically. When Engine Two gets back online, it still has a significantly lower thrust than Engine One.

• Why does Engine Two flame out and not Engine One?
  • Better yet, why not both at the same time?
• How can I set the intake to distribute air equally to both engines?

 

I don't know if it's been asked already, but if it has could someone please send me the link to a reliable answer? Thank you.

 

[steuben]

Quote

• Why does Engine Two flame out and not Engine One?
  • Better yet, why not both at the same time?

The game assigns engine air to engine one until all its needs are met. Then starts assigning to engine two, and so on. It looks like at 11km there's not enough air coming in to run both engines at the same time. I don't think the G50 is designed for that particular operating envelope. I strapped on four Ramp intakes for the same intake area and it did a better job at keeping both engines lit.

I think there is a mod for equal air distribution... but I couldn't tell you what it is.

 

[Adenosine Triphospate]

Its really just the air intake thats the problem. I've tried a similar design, and I encountered the same problem. I have no idea why one engine flames out but not the other, since they both feed from one intake.

However, I do know that the air intake is simply not designed for speeds exceeding 400 m/s! I'd recommend 4 radial adjustable ramp intakes, or two (or one in the middle will be fine) shock cone intakes, however, these are not radially mountable so will require a design change. They have better performance for the speeds you're travelling at.

 

EDIT: Just out of interest, is there any reason to have the canards mounted on the nose at a strange angle? Is it to balance the aerodynamics or just aesthetics?

Edited May 26, 2019 by Adenosine Triphospate

[bewing]

When you built the plane, one engine was created first, and the other was created second. If you have two air intakes, one will be assigned to each engine. But if you only have one intake, then it will feed one engine first.

 

[Aegolius13]

2 hours ago, Adenosine Triphospate said:

Its really just the air intake thats the problem. I've tried a similar design, and I encountered the same problem. I have no idea why one engine flames out but not the other, since they both feed from one intake.

However, I do know that the air intake is simply not designed for speeds exceeding 400 m/s! I'd recommend 4 radial adjustable ramp intakes, or two (or one in the middle will be fine) shock cone intakes, however, these are not radially mountable so will require a design change. They have better performance for the speeds you're travelling at.

 

EDIT: Just out of interest, is there any reason to have the canards mounted on the nose at a strange angle? Is it to balance the aerodynamics or just aesthetics?

You could also stick a precooler in front of each of the engines (though this would lengthen your ship a bit).  They're my go-to intake when I don't have a 1.25m front node available for a shock cone.  

[Aeroboi]

That particular intake isn't very good for super/hypersonic speeds. Some of them will reduce feed intake air as speed increases as these intakes are meant for sub/transonic speeds. You can still use any of the air intakes like the ones used at those speeds but it fails to intake all the air it could on lower airspeeds.
Also, intake air is proportional to speed. So if you were going faster then 900+ m/s at 11km altitude you'd last longer.

In your particular design I would use the Adjustable ramp air intake. You will need quite a few of them, what's wondrous about them is that they're very lightweight and very aerodynamic. They aren't very heat resistant, however, attaching them on the top will cause heat friction to be absorbed at the front so these intakes should be protected from heat as long as you keep the nose up during aerobraking.

You could also re-design the ship, remove one Mk2 fuel tank in the middle or use a shorter one, then use the other Mk2 inline cockpit and use a mk2 to mk1 adapter with a shock cone intake at the front and remove the other intake at the back.

[Flibble]

12 minutes ago, Aeroboi said:

You could also re-design the ship, remove one Mk2 fuel tank in the middle or use a shorter one, then use the other Mk2 inline cockpit and use a mk2 to mk1 adapter with a shock cone intake at the front and remove the other intake at the back.

I rather like the shock cone as a nose design, I used one very successfully - a single shock cone can feed two whiplashes without an issue.