Jastreb stock prop-driven plane with max speed of 255m/s

[_Rade]

Jastreb (hawk) is a stock airplane powered by electric propellers. It is specifically designed to test just how fast you can fly with the stock propellers.

In order to reduce the drag I've used small wings and minimum number of parts required to build the plane. Also with the exception of the rotor blades all of the engine parts are inside the fairing and therefore shielded from the drag. All of this really helps to increase the max speed of the airplane.

Previous version of this plane had max speed of 240 m/s at low altitude. After a few tweaks and adding few more reaction wheels to each engine (35 small reaction wheels per engine) I've managed to push the max speed to 255 m/s or 918 km/h. Because of the small wing area airplane won't behave so well above 5k, however it can climb to 10k but you won't be able to maintain level flight at that altitude.

I've even managed to barely break the speed of sound by doing a steep dive from 10k. Jeb barely survived the crash landing in the water because I didn't get out of a dive in time, only the cockpit survived.

 

Link to the craft file and the instructions how to fly the plane:

https://kerbalx.com/Rade/Jastreb

Edited February 6, 2017 by _Rade

[Ravenchant]

>looks at roundel

I'm sure RYAF wouldn't have minded to have a couple of these before the war

[Majorjim!]

Great work on this man! It's a great looking aircraft.

 The electric prop reminds me of a modern submarines prop, very cool. Keep it up!

[Jett_Quasar]

I downloaded the craft - it works really well.  It would do great as an Eve explorer (much better than what I had planned).  I'm still trying to figure out how the bearings work...

- Jett  

[_Rade]

@Ravenchant

That would be some really interesting alternate history.

@Majorjim!

These remind me of the General Electric GE36 propfan engines. This layout allows me to keep everything inline and to minimize the drag, also it reduces the chance of the rotor blades hitting the runway on takeoff. I think that with this layout I'm getting close to the max possible speeds for the propeller driven aircraft in game.

Another solution I've tried is something similar to the Dornier Do 335, with one engine in the front and another in the back of the airplane. But so far none of the airplanes with this layout could get past 210 m/s. Also these require me to use large landing gear in order to prevent the tailrotor from hitting the runway.

@Jett_Quasar

Bearings for these engines are fairly simple, it is just 2 or 3 stayputnik probes located inside the fairing, along with the reaction wheels and RTG's. Depending on the size of the engine short or long I-beam is used as the root part in order to give the rigidity to the engine.

If you want to make your own I would suggest taking apart the engine from one of the other airplanes I've made. One of those should be easier to figure out than the engines I've used here.

I've tested the older version of this plane on Eve and it worked really well. Only problem is that because the engines are separate from the airplane it would be single use only. Because if you leave the physics range and then return the plane would fall apart.

I did make a version of the engine that uses the claw inside the fairing to reattach the propellers to the plane. You can take a look at the Dunasoar topic to see how those work. @Mikki have quite successfully  used one of these planes to explore Duna on his DBP mission. For the Eve you would need more reaction wheels inside each engine and probably fewer number of rotor blades.

[Jett_Quasar]

Good to know...  I was actually using a compact bearing designed by MajorJim! for my engine, but it suffers from the same issue that yours does being two separate parts.  There must be a way to fix that.

It also spins more slowly because I'm using a  Narrow-Band Scanner as a drive motor.  

- Jett

[Azimech]

54 minutes ago, Jett_Quasar said:

 There must be a way to fix that.

 

If you ever find one, let me know.

[Rath]

1 hour ago, Jett_Quasar said:

Good to know...  I was actually using a compact bearing designed by MajorJim! for my engine, but it suffers from the same issue that yours does being two separate parts.  There must be a way to fix that.

It also spins more slowly because I'm using a  Narrow-Band Scanner as a drive motor.  

- Jett

Thats really interesting.  The narrow-band scanner has infinite torque (To the extent of the materials), so perhaps it could be geared to be faster?

[Jon144]

6 minutes ago, Rath said:

Thats really interesting.  The narrow-band scanner has infinite torque (To the extent of the materials), so perhaps it could be geared to be faster?

My problem with the scanners is that due to the infinite torque they tend to physically phase through bearings when under heavy load so it's hard to gear them to high speed applications unless you really know what you're doing.

[klond]

10 hours ago, Jon144 said:

My problem with the scanners is that due to the infinite torque they tend to physically phase through bearings when under heavy load

 If we made a clutch we could ease the load in.  Use like landing gear with brakes maybe so it slips a little and you can set the friction.

 I think the scanner would make a nice ship propeller motor.

[Heckspress]

do it @klond you glorious bnastard

EDIT: there is now a word-filter, this'll be fun 

Edited February 7, 2017 by Heckspress

[Deizelpunk]

DAMN MAN! SICK AS KRAKEN JUICE! Impressive work, i've never gotten a stock prop plane past like 30 m/s LOL

16 hours ago, Rath said:

Thats really interesting.  The narrow-band scanner has infinite torque (To the extent of the materials), so perhaps it could be geared to be faster?

Oooh! That sounds like a neat idea! might give that a shot

[_Rade]

18 hours ago, Jett_Quasar said:

Good to know...  I was actually using a compact bearing designed by MajorJim! for my engine, but it suffers from the same issue that yours does being two separate parts.  There must be a way to fix that.

It also spins more slowly because I'm using a  Narrow-Band Scanner as a drive motor.  

- Jett

Only way I've managed to fix it is using the claw to grab the rotor when it's not in use.

Narrow-Band Scanner doesn't spin fast enough to be used to power the rotor. Did anyone try to stack few narrow-band scanners inline, each spinning the next one in order to get higher rotation speed.

[Jon144]

On 2/7/2017 at 8:33 AM, klond said:

 If we made a clutch we could ease the load in.  Use like landing gear with brakes maybe so it slips a little and you can set the friction.

 I think the scanner would make a nice ship propeller motor.

I tried to integrate a scanner drive into one of my mega-trucks a few months ago but instead of grabbing the bearing it would start slipping through it. So unless you have a few million struts it may be difficult to hold the scanner in place. From my experience they coat these things in butter.

[Rath]

I've started working on a geared scanner rotor, and I have build a new scanner holding system.  Clip two scanners into eachother in an X shape, and lock them to the rotating part with four short I-beams.  It seems to be much more stable and stronger too.

[klond]

I was headed in this direction

 I'm trying to convert it to horizontal.  Pressing the brakes help ease in the load.  It needs a way to 'lock it in' so we can get rid of the slip when it's up to speed .

[Rath]

3 hours ago, klond said:

I was headed in this direction

 I'm trying to convert it to horizontal.  Pressing the brakes help ease in the load.  It needs a way to 'lock it in' so we can get rid of the slip when it's up to speed .

Maybe push in beams that lock it in place with landing gear?

 

EDIT: http://imgur.com/a/H51fE

 

Edited February 12, 2017 by Rath

[Rath]

I made a narrow-band scanner thread, so we can stop derailing this one.  http://forum.kerbalspaceprogram.com/index.php?/topic/156566-narrow-band-scanner-rotor-thread/