Eve electric prop airplane speed record?

[Hotel26]

Not sure where to ask this -- but: I would like to find out what is possible, speed-wise, on Eve.

I have finally landed my first propeller airplane on Eve, Electroglide.  It carries 6 and currently I am seeing 76 m/s @ 5.2 km.

It's just a bit slow for exploration of a big, old, nboring, purple planet like Eve.

So, I'd like to know what the state of art is.  What is the fastest anyone has traveled through the atmosphere on Eve in a conventional electric prop airplane?  (I do prefer e.g. 6 seats rather than the usual 1-seat solution, but I suppose the latter has its place.)

                                                                               

Electroglide:

 

 

UPDATE: I've found one that is claimed to fly at 128 m/s.  Might be able to adapt its propulsion scheme...

https://forum.kerbalspaceprogram.com/topic/197265-solar-electric-eve-plane/

 

Edited March 15 by Hotel26

[DennisB]

My Eve plane was optimized for low speed, safe landing, high altitude flight and science collection. It could reach 50m/s at low altitude, 55m/s at cruising altitude (4-7km) and 83m/s at maximum altitude (22km). It had a Mk2 cockpit for two kerbals, a cargo bay for all science experiments and foldable wings for easier transport on a rocket. It could land on the sea, but couldn't take off. It was patience necessary, but I explored Eve with it, and visited all biomes.

Edited March 15 by DennisB

[Lt_Duckweed]

229.4m/s (approximately Mach 0.9) in level flight at 13.7km

 

A few tips:

1. For whatever reason, for the 2x4 fixed panels, long side edge on into the airflow is lower drag than any other setup, especially the left long side (going by the default orientation when attaching it to a forward facing part in the SPH).
2. For the size rotor you have, 6 panels is massive overkill.  1 2x4 panel is more than enough for a single small rotor.
3. Ducted fan blades are better than propeller blades in pretty much every conceivable metric (and shrouds are cosmetic only, you just need the blades)
4. Due to lower speed of sound on Eve, I get better results limiting RPM to 400.
5. If you offset the base of the fan blade directly inwards towards the axis of rotation, it will improve the thrust to torque ratio on the blades, so you can run more per rotor.  The farthest you can go is one shift tick past the axis of rotation (so the base of the blade is on the other side from the rest of the blade).  This should let you comfortably run a pair of large ducted fan blades on the smallest rotor
6. Run a pair of two blade rotors, with two solar panels.  This should get you a lot more thrust and greatly increase top speed, but will not effect your overall mass much since you removed the extra solar panels.
7. In low light conditions where 2 panels may not be enough, simply lower the torque limit on the rotors a bit.  This will lower your top speed a bit, but it will still be a lot faster than you are getting right now.

Edited March 15 by Lt_Duckweed

[king of nowhere]

I got 140 m/s with a half-assed design i scrambled together in a short time as part of a larger mission. Very basic plane, but it flew thousands of kilometers. 

Can't post links from mobile, but it's linked in my signature, the Bolt/Nail mission, Eve chapter. 

That kind of performance is easy to get if one does not overengineer the plane - you appear to have a small rotor on a relatively big plane, which limits performance.

Getting faster is harder. I know @Lt_Duckweed as a great expert of planes, if 229 is his best attemp, it's probably close enough to the upper theoretical limit

[Hotel26]

9 hours ago, Lt_Duckweed said:

A few tips

Excellent and very helpful information from all.  Thank you!  All others welcome to describe their own experience/insights...

I will report back to this topic when I have a satisfactory result (or more specific questions).

Cheers!

Edited March 16 by Hotel26

[Hotel26]

OK.  This is Elektra.

168.5 m/s at 6.6km (without any attempt to fly higher yet, since my destination is Mauve Mountain, 167E).

The nice thing, too, with counter-rotating props, is that it is stable with SAS and/or Atmospheric Autopilot.  Yay.  That makes long trips so much shorter.

Only concern is the contrails from the props.  They are so short, I didn't punch them in as directed since they would have almost disappeared.  That may mean that the tips have gone transsonic and are causing drag...?

 

Edited March 16 by Hotel26

[TheFlyingKerman]

I built this modest plane that flies at 170m/s at 20000 m on Eve, using about 20% torque from the smallest motor. Flying higher helps.

https://ibb.co/k3dYsbM

It is capable of vertical landing and takeoff.

https://ibb.co/xDHYJFF

In my experience speed isn't the most important factor for a plane on Eve, rather its size and hence how well it can survive entry in to Eve's atmosphere.

https://ibb.co/cYMFvnY

https://ibb.co/fnpsFN1

 

Edited March 16 by TheFlyingKerman

[Hotel26]

2 hours ago, TheFlyingKerman said:

it can survive entry in to Eve's atmosphere.

Yep.

I use Harpoon for my Electroglide (now Elektra)...

So size is no object [fine print: as long as it fits in the largest size fairing]...

I have found also that using a "reverse booster" of whatever size is required is an adequate and uncomplicated way to take any moderate payload mass down to the surface.

(I have recycled dozens of boosters to Eve for this purpose over the years.  )

My notes on the Eve Descent Profile:

• decelerate to 2 km/sec in order to deorbit
• reaching 70-75km, decelerate to 1.2 km/s (extend airbrakes if available)
• reaching 50 km, decelerate to 800 m/s by 40km

 

Edited March 16 by Hotel26

[Hotel26]

2 hours ago, TheFlyingKerman said:

It is capable of vertical landing and takeoff.

Btw, I love your concept.  

[Lt_Duckweed]

On 3/16/2024 at 2:03 AM, Hotel26 said:

Only concern is the contrails from the props.  They are so short, I didn't punch them in as directed since they would have almost disappeared.  That may mean that the tips have gone transsonic and are causing drag...?

With the altitude you are at I wouldn't worry about this.  While the speed of sound is around 250m/s up at the altitudes where I was flying in my example, down where you are it's going to be closer to 285m/s.  So your props have gone slightly supersonic, however, slightly supersonic is ok, as the ducted fan blades don't hit their performance wall until around Mach 1.2

You could extract a bit more speed with more tweaking of the prop, but if you are happy with what you have, its a pretty good result.