Ion Plane Research Challenge

[Deddly]

I did a little work on this today and I discovered that stacking the mighty Basic Fin like @Archgeek did turned me into Dany2462. Did you have any trouble with those fins creating powerful craft-destroying phantom forces?

 

[Archgeek]

3 hours ago, Deddly said:

I did a little work on this today and I discovered that stacking the mighty Basic Fin like @Archgeek did turned me into Dany2462. Did you have any trouble with those fins creating powerful craft-destroying phantom forces?

 

No I did not.  I get some occasionally major sideslip, and now that we're into 1.1.2 I've had some serious grief from the suspension tweakables (Did they document what spring strength and damper actually do?  I'd assume spring's obvious and damper's like a dashpot, controlling movement attenuation, but that's clearly not the case as zero spring and max damper leaps violently into the air).  The fins largely produce some lift and a hilarious glide slope.

I did find that the large static panel really doesn't produce a whole lot of drag.  In fact, with a juno forcing the thing to over 170 m/s, the only major drag sources seemed to be the wheels, and anywhere I had something solid in front of an octagonal strut.  The drag arrow on the first battery was obviously just from the head of the stack, but notably if I had an octagonal strut or two, then another battery, then another octagonal strut, a new largeish drag arrow would appear from the battery, as though the airflow was coming back in around the first part of the fuselage and into the space of the octagonal struts until it hit something more solid again.

[Srgtjyn]

any tips to keep the thing straight on the runway?

[The_Rocketeer]

1 hour ago, Archgeek said:

with a juno forcing the thing to over 170 m/s, the only major drag sources seemed to be the wheels, and anywhere I had something solid in front of an octagonal strut.

With such tiny thrust output, any source of drag at all is near-crippling. In the case of solar panels, you have to multiply the drag of one panel six or eight times per engine, which all adds up. I think this is why accelerating over 10m/s is so difficult. Getting near 10m/s isn't too hard, but once you increase thrust to push beyond, the exponential increase in drag really starts to bite.

[Srgtjyn]

3 minutes ago, The_Rocketeer said:

With such tiny thrust output, any source of drag at all is near-crippling. In the case of solar panels, you have to multiply the drag of one panel six or eight times per engine, which all adds up. I think this is why accelerating over 10m/s is so difficult. Getting near 10m/s isn't too hard, but once you increase thrust to push beyond, the exponential increase in drag really starts to bite.

Is that solar panel drag directional? Could they be used as "wings" as @EpicSpaceTroll139 said?

[GraviTykillz]

My attempt..I have used Ions in lots of my Space Crafts.never in a plane.

So..towing up my Ion Glider

and below..couldn't maintain level flight..Might try again..Seems difficult

 

[wibou7]

Here is a full album of (a slightly modified version of) the Winter Goose in flight.

I tried to give it a bit more autonomy. It kinda worked but the minimum altitude is now even higher. I didn't test for sure but I don't think it would be be capable of level flight below 5000m.

There is still room for improvement, though. I could probably remove 2 of the ailerons, maybe 4. That would give slightly less drag, so I could maybe remove an engine. Replacing the large battery with small ones could be something to try as well.

The margins are so tight anything could make a difference.

 

[Pds314]

Using Ferram Aerospace Research, but I figured I'd post my attempt anyhow.

Started near the top of Mt. Keverest. At first, I didn't think I would get enough power to climb. Incidentally, this means my freestyling altitude is probably in the mid 5000s of meters. (at that latitude anyhow).

Things were going well until I hit the transonic barrier. Managed to eventually overcome it and reach 810.1 m/s at 30k. It may also be that if I lighten this vehicle, the TWR will go up to allow it to climb all the way to orbit. If it isn't obvious, I used a fuel cell array and a lot of LFO instead of solar panels. While it does add considerable weight, it means I don't have to fly under the sun.

I'm convinced that either through better piloting, supersonic optimization, drop tanks, or other means, orbit is possible

 

 

Edited May 4, 2016 by Pds314

[Deddly]

@Pds314 Although this is a stock only challenge, it's nice to see what you were able to do with F.A.R. Any chance you could try the same craft from the same location on a stock install?

[Pds314]

1 hour ago, Deddly said:

@Pds314 Although this is a stock only challenge, it's nice to see what you were able to do with F.A.R. Any chance you could try the same craft from the same location on a stock install?

I'll try rebooting with stock. I'll have to make adjustments because I had the wings set to minimum weight.

I guess also in stock, lift is considerably higher, so that should help somewhat. Transonic effects are also reduced, as are supersonic.

Hmm. I strongly suspect a wide delta is not the best stock wing profile. I mean, in FAR, it's a good compromise, but in stock, I'm not sure it has any real advantages. It might also be overly lifty.


Hmm.. well, it gained like 400 kilos changing to stock, so hopefully that lift is enough. =/

Tried stock. No good. It attains an L/D of 9, but it needs more like 12 during those first critical moments. Messing around with the craft hasn't helped, included attempting to add drop engines and fuel cell arrays to match. It just increases drag. I think I will continue later, but I'm going to try some more abusive practices with the fuel cell arrays and the ions to make it sleek. In particular, piling a bunch of them into a very small space inside a cargo bay or fairing to hide their drag. 18 engines didn't seem to work because at that point it can't get the L/D above 4, so I need to fair them somehow.

(In other words "why does this Mk2 cargo bay weigh 10 tonnes?")

Edited May 4, 2016 by Pds314

[Pds314]

Wait a minute...

Ions consume next-to-no fuel....

While I unfortunately can't build a turboshaft out of ion engines, I CAN build a rocket-tipped-helicopter with them! I've already got a bearing design that should allow for efficient lift with <0.4 kN*m of torque loss due to bearing friction. The main thing is that it needs a TWR over 1, and probably a plane that stages once it goes up high enough.

Heck, I'm not even sure I need the ions. It might be possible to get the thing high enough to launch planes using SAS torque.

Edited May 4, 2016 by Pds314

[The_Rocketeer]

15 hours ago, Srgtjyn said:

any tips to keep the thing straight on the runway?

Use some kind of rudder control surface and keep SAS on. Also, properly adjusted wheel suspension will help, the craft seems to drift off centre because of suspension over/underloading (note: not wheel load).

 

 

15 hours ago, Srgtjyn said:

Is that solar panel drag directional? Could they be used as "wings" as @EpicSpaceTroll139 said?

Theoretically yes - I actually suggested this in post 7 of this thread. However the 'lift' generated is so inefficient that you need considerably higher take-off speeds to be able to use it, and with ions only the thrust just isn't there. To me this seems like a dead end.

[The_Rocketeer]

4 hours ago, Pds314 said:

Using Ferram Aerospace Research, but I figured I'd post my attempt anyhow.

Started near the top of Mt. Keverest. At first, I didn't think I would get enough power to climb. Incidentally, this means my freestyling altitude is probably in the mid 5000s of meters. (at that latitude anyhow).

Things were going well until I hit the transonic barrier. Managed to eventually overcome it and reach 810.1 m/s at 30k. It may also be that if I lighten this vehicle, the TWR will go up to allow it to climb all the way to orbit. If it isn't obvious, I used a fuel cell array and a lot of LFO instead of solar panels. While it does add considerable weight, it means I don't have to fly under the sun.

I'm convinced that either through better piloting, supersonic optimization, drop tanks, or other means, orbit is possible.

Seems to me that from these starting altitudes you're only really facing the same problems that we had in the Collier Trophy thread. FAR had a headstart then too, which IIRC had a lot to do with lower drag. It might be worth reading over the thread, the ultimate champion even posted his .craft file which is still a viable link, though in those days we used a lot of massless parts and a lot of wing-strakes. His approach was also to use a lot of batteries.

[Pds314]

As for takeoff from KSC, it's probably not happening in stock. The ions have a TWR of like 0.024. That means that landing gear drag is eating up most of your thrust, and the bare minimum L/D for sustained flight is like 40+, and that's with a craft that's almost pure ion engines. I'm not sure an L/D of 40 is possible in stock.

EDIT: hmm.. I seem to have found a method of generating magic force on the ground. Definitely investigating.

Edited May 4, 2016 by Pds314

[Moesly_Armlis]

On 5/3/2016 at 5:54 AM, Deddly said:

forward to further progress reports

There was some progress in creating an improved trebuchet   The earlier problem seemed related to struts that would be ok in the SPH butt then stick out at odd angles and into free space when on the launch pad.  Changing root parts and then translating the device through the roof of the SPH made it difficult to catch.  Solution was to reduce struts and build on the one side then copy in mirror.  The trebuchet also now uses stack separators instead of launch clamps which makes it easy to identify when shuffling stages.  It is fun building this but certain the ion part of the glider is not contributing other than for its mass.

 

The latest revision has improved the strength too much and now the pivot doesn't break nor bend.

 

The ion engine is somewhat useless under 5km altitude.  The prior testing revealed not enough force was created to achieve anywhere near that altitude.  Somehow this apparatus would need to be mobile and that would then exclude launch clamps. 

The pivot point is the key to this puzzle and some pointy hat ksp players seem to have made rotors and bearings.  Never have studied that type of magic before but seems astonishing what can be accomplished in KSP.

 

edit

Now that did not take too long.

@Majorjim Thank you for posting.

 

Maybe another trebuchet challenge should be started though.

Edited May 5, 2016 by MoeslyArmlis

[Majorjim!]

Just now, MoeslyArmlis said:

There was some progress in creating an improved trebuchet   The earlier problem seemed related to struts that would be ok in the SPH butt then stick out at odd angles and into free space when on the launch pad.  Changing root parts and then translating the device through the roof of the SPH made it difficult to catch.  Solution was to reduce struts and build on the one side then copy in mirror.  The trebuchet also now uses stack separators instead of launch clamps which makes it easy to identify when shuffling stages.  It is fun building this but certain the ion part of the glider is not contributing other than for its mass.

 

The latest revision has improved the strength too much and now the pivot doesn't break nor bend.

 

The ion engine is somewhat useless under 5km altitude.  The prior testing revealed not enough force was created to achieve anywhere near that altitude.  Somehow this apparatus would need to be mobile and that would then exclude launch clamps. 

The pivot point is the key to this puzzle and some pointy hat ksp players seem to have made rotors and bearings.  Never have studied that type of magic before but seems astonishing what can be accomplished in KSP.

 

edit

Now that did not take too long.

@Majorjim Thank you for posting.

 

Maybe another trebuchet challenge should be started though.

What's all this?

 That's an old. old bearing that most certainly wont work now with the new wheels (broken as they are).

 What bearing did you use in the trebuchet?

[Moesly_Armlis]

15 minutes ago, Majorjim said:

 That's an old. old bearing that most certainly wont work now with the new wheels (broken as they are).

 What bearing did you use in the trebuchet?

No bearing at all.  Just the power of struts and launch clamps.

Warm beverage has been poured and I am just about to launch KSP and investigate your newest research into thermometers.as hinges.

Edited May 5, 2016 by MoeslyArmlis

[Majorjim!]

Just now, MoeslyArmlis said:

No bearing at all.  Just the power of struts and launch clamps.

Warm beverage has been poured and I am just about to launch KSP and investigate your newest research into thermometers.as hinges.

Nice.

 Bear in mind it is not designed to hold heavy loads. It is a low weight door hinge primarily. You can, and others have copied the shape of the cage holding the moving part. Just use larger stronger parts and you can have a high weight holding bearing. The trick is the shape of the cage.

[Moesly_Armlis]

Was about to tro out @Majorjim idea of thermometers and just as I entered the SPH the idea of using other parts became front and centre.  The heavy mass might not be supported.

 

The first part I selected looked suspiciously like a sleeve  it was the newish part the Structural Fuselage.  Combined with again my first choice a Modular Girder Segment XL and I was off to the races.

 + = AWESOME!

 

The two items were constrained and the weight rotated around the axis.

The ends of the girders have panels and the structural fuselage was temporarily held with separators.  The bearing sleeve is held in place by launch clamps  This is the beginning of something different and will start a new thread and provide more detail.  Bearings it seems are not as complicated as I thought it would be.

... yada yada yada

.the trebuchet was increased and

 

the ion glider was attached and flew pretty far.

 

http://i.imgur.com/iYac5ZR.gifv

Edited May 5, 2016 by MoeslyArmlis

[wibou7]

1 hour ago, MoeslyArmlis said:

Was about to tro out @Majorjim idea of thermometers and just as I entered the SPH the idea of using other parts became front and centre.  The heavy mass might not be supported.

<crazy trebuchet idea>

 

 

WOW!  Very very impressive!  You really are the king of the cavemen.

Sadly, no level flight yet
Maybe if you enlarge the lifting surface by A LOT it could somewhat substain level flight..?

[Draconiator]

I'm still working on the problem as well.  Here's my carriage idea:

 

I took that picture an hour ago so 3 Junos evolved into 1 Whiplash, and maybe 2 if I can't get to altitude fast enough.

[Draconiator]

I THINK I GOT IT!!!  Video soon, need to fine-tune

[Moesly_Armlis]

This is the outcome of creating a larger trebuchet.  Come to think of it a trebuchet has a pivot for the counter weight so this is more catapult.

The craft file is linked over on the trebuchet thread.  Enjoy.

 

[The_Rocketeer]

1 hour ago, MoeslyArmlis said:

This is the outcome of creating a larger trebuchet.  Come to think of it a trebuchet has a pivot for the counter weight so this is more catapult.

The craft file is linked over on the trebuchet thread.  Enjoy.

 

I enjoyed watching this.

You're right about the counter-weight pivot, but actually I think for better results you want a second pivot in the throwing arm (labelled 'Sling' below - not my artwork).



 

[Draconiator]

I still cannot believe this actually worked...Ion planes ARE possible!