The Dunatian

Should the "Wheesley" Engine be Changed?

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The Wheesley is my go-to engine for any non-giant aircraft I'm planning on landing on non-runway terrain, and I tend to build a lot of those, so I end up using it way more than the Panther.

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I NEVER use the Panther and almost ALWAYS use the Wheesly...

:P 

So forgive me if this statement is wrong, but isn't the Panther like...super fuel hungry..?

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53 minutes ago, Spacetraindriver said:

I NEVER use the Panther and almost ALWAYS use the Wheesly...

:P 

So forgive me if this statement is wrong, but isn't the Panther like...super fuel hungry..?

Yes and no. The Panther does extremely well at higher velocities (Mach 2+ and altitudes that the Wheesly just can't. But up to Mach 1.5 the Wheesly does just fine. 

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In dry mode, the Isp is 9000 vs the whees' 10500... its total thrust is lower (at least mach 1 and below), so its not super fuel hungry, but it is a bit more fuel hungry. Its Isp is very good compared to the whiplash/rapier/juno.

In wet mode, its got the same Isp and static thrust as the whiplash, which is quite fuel hungry (but not as bad as rapiers)

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9 hours ago, sal_vager said:

Now I think the Wheesley needs changing, back to 100% reverse thrust...

I agree. I was a bit surprised by these news, as I read all the change-logs very carefully and I never noticed this change. Must have missed it.

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I don't use the Wheesley for anything. The Juno is fine for all of my low speed/ low altitude science in early career. By the time I need more performance, I've unlocked the Panther.

Best,
-Slashy

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its the only time I build planes in career mode, I can just not get the juno to work

its a good early career mode engine

Edited by StupidAndy

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Sometimes I would find the Weesley a good engine for shuttles that need to a powered landing.  They might take off on big rocket engines that get discarded and make their orbital adjustments on light rocket engines, but once they are back in atmosphere the light rockets will generate insufficient thrust for the pressure they are in and consume what little fuel it has left too rapidly.  The Weesley has just the right balance of low weight and decent (but not great) atmospheric thrust to make it good for guiding a shuttle to the runway under its own power.  It is either that or do an unpowered glide, which can turn out pretty disastrous if you misjudge any part of your reentry process.  

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To be fair, perhaps junos are better for that...or even a panther. Oberth effect still applies, and if you realize you need to make an adjustment earlier when you're higher and faster, its better.

Both the Juno and Panther (in dry) have better thrust curves above ~ mach 0.5, so if you're going to be engaging engines while still over 300 m/s to adjust your glide slope to landing, the juno or panther will probably do more for you. They both have less mass as well, with the juno in particular having a lower frontal cross section.

Also, the Panther can provide reasonable launch assistance as well.

Consider this flyback booster-shuttle, it launches with the panthers in wet mode:

oVu7wmp.png

but the panthers are mainly there for flying back:

vaDw4vc.png

and the afterburners are great for those moments when you realize you misjudged a bit and need more thrust immediately (yes, I pulled off this landing)

e2TDeje.png

The panthers have less mass, they provide more assistance during launch, and their afterburner fuel consumption isn't a problem if only used a few seconds before touchdown. They start providing useful thrust at higher speeds than the whees'

gDFLu6R.png

Don't get me wrong, I'm not saying the whees is useless... but I don't think use on shuttles is a good fit for its capabilities.

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People don't use the Whiplash anymore either. The Panther shouldn't have been added, or should be weaker in some way for being able to replace both engines for most purposes.

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People di use the whiplash, and when i have time ill link a thread where others will tell you that the wet panther absolutely dorsnt replace the whiplash. The whiplash suffers more from competition with the Rapier, not the panther.

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Pretty sure when it comes to spaceplanes the Whiplash is still commonly used. It faces competition from the RAPIER, but Whiplash+Nerv to go liquid fuel only is popular.

As for the Wheesley, I'm not sure what could be done? Like most of the jets, it's already more efficient than the real thing. Since it's supposed to be a turbofan it shouldn't be running much past Mach 1.5 and nor should it be very good on TWR. It does have reverse thrust as its feature.

Maybe it's the aero model that's giving the Panther a practical advantage? KSP Wiki mentions that because the Panther can supercruise faster, that makes the fuel efficiency better than the Wheesley per mile even if the Panther burns more fuel per minute, but if supersonic drag is wonky that could be skewing the behaviour.

And maybe the Wheesley just has to be one of the small number of parts that's 'balanced' largely by its tech tree location.

Edited by cantab
correction

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On 2/24/2017 at 2:43 PM, cantab said:

Pretty sure when it comes to spaceplanes the Whiplash is still commonly used. It faces competition from the RAPIER, but Whiplash+Nerv to go LFO only is popular.

...

Since it's supposed to be a turbofan it shouldn't be running much past Mach 1.5 and nor should it be very good on TWR.

Well, the Rapier is still what I use on LF-only planes (I wouldn't say LFO, because that can be mistaken for LF+Oxidizer). Just because it can use Oxidizer in closed cycle doesn't mean it has to. It still gets you higher and faster than a whiplash, which is very good if you're relying on a Nerv to get you the rest of the way to orbit.

Second, for non-afterbuning turbofans, the speed value is about right... particularly high bypass turbofans... but even non-afterburning turbofans can have excelled TWR. Keep in mind that the harrier used just a single large turbofan.

Ant the F-35: when it hovers, its not using the afterburner to provide additional thrust (doing so would be a hazard to crews and damage landing surfaces) - its using a lift fan: it essentially converts to a high bypass turbofan. Take the big honking fan on the front of an airliner... extend the shaft so that the fan is at the front of the plane, but a gearbox so that the fan's rotation plane is perpendicular to the shaft: its now a lift fan. The X-35 beat the X-32 in large part because the X-32 was using the same basic lift system as the harrier, and the TWR was too low, requiring massive redesigns well into the competition.

The X-35's lift fan system is what sealed the deal.... and its basically a fancy conversion of a low bypass turbofan into a high bypass one. Extending this even further, a turboshaft powered helicopter is basically an ultrahigh bypass turbofan, and those have great TWR.

Turbofans are actually pretty darn good as far as TWR is concerned... they may be a bit bulky because of the cross section required for all the bypass air, but their TWR is actually pretty good.

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I use the Wheesley for mid-high altitude subsonic long range craft. Useful on craft with small wings, as I can land at a high speed and use the thrust reverser.

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In my current  career game the Wheesley is quite usefull as it is.

In earlier games I too blasted past the first half of the tech tree (farm Minmus), and never touched the Wheesley. But now I'm doing a hard-mode carreer.

I cut down on the science pay-out, disabled the DSN ground stations, added life support, play from IVA (with IVA props, of course), and limited reverts (biggest trouble, a failed launch nearly bankrupted me)

My options for unmanned probes are limited (expensive infrastructure not yet available or present). And my manned missions haven't ventured past orbit yet (life support requires a lot of power)

 

Since farming Mun/Minmus isn't on the program yet, planes are a must. I never enjoyed Kerbin this much!

 

With four Juno's my Recon 1 plane was capable of cruising at mach 1, at 6 km height, and it comes with a reliant rocket engine (909 not yet available) to push it above 19.4 km for 'in flight above x' contracts.

Its range is very limited though. I had to glide back to KSC on several occasions, and the rocket only has enough juice for 2 jumps.

 

Unlocking the Wheesley was a major milestone. 

 

Three Weesley's can hold the Recon 2 at a steady mach 2.05 cruise at 8-9 km (rock solid, even at 2x or 3x time accel). Its power and speed unlocked Kerbin for my program! (save for imprecize ICBM's, which are a waste of money to recover). If flown right it can even jump up above 19.5 km! (takes a 100 km run. Hold mach 2 at 10 km, at 1 minute distance gently nose up 50 degrees)

 

 

Without the Wheesley (or equivalent) in its current form, hard-mode games like mine are doomed. 

It's an ideal engine for late-lvl 1 technologies, and to milk Kerbin dry of science.

The Panther is for midgame hypersonic planes (quickly try the new experiments), and the Whiplash is great for early horizontal take-of space planes. Every engine has its niche.

 

Also, please keep the reduced reverse-thrust, it would be very weird if such an engine could generate the same thrust in reverse. The above mentioned ~70% sounds about right.

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On 2017/2/24 at 5:59 AM, Fearless Son said:

Sometimes I would find the Weesley a good engine for shuttles that need to a powered landing.  They might take off on big rocket engines that get discarded and make their orbital adjustments on light rocket engines, but once they are back in atmosphere the light rockets will generate insufficient thrust for the pressure they are in and consume what little fuel it has left too rapidly.  The Weesley has just the right balance of low weight and decent (but not great) atmospheric thrust to make it good for guiding a shuttle to the runway under its own power.  It is either that or do an unpowered glide, which can turn out pretty disastrous if you misjudge any part of your reentry process.  

I think panther is more suitable for shuttle landing assist, it have better performance at high speed.

When the jet running at high attitude (high speed), it have higher efficiency, make the shuttle go further.

And the wide vector range help the shuttle pitch up at the last moment of landing

The down side of panther like lower ISP and heavier are not important for a giant MK3 shuttle

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The way I see it, the Wheesley fills its niche (that of a Mk1-sized high-efficiency subsonic engine) very well. The problem is that stock KSP doesn't really provide a use for that particular type of engine. If you're building a plane in KSP it's probably either going to be a SSTO spaceplane (in which case you need at least Panthers and preferably Whiplashes or R.A.P.I.E.R.s to get as much altitude and velocity as you can before switching to rockets) or a science-gathering atmospheric plane (in which case you're still better off going with Panthers so that you can made those ~20km observations.) If you want to make a long-range passenger or cargo plane the Wheesley would be great, but the game doesn't provide any need for that type of craft.

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I had no idea the wheesley could reverse. I am such a plane noob. 

This changed my whole outlook plane based science missions.

I guess you have to tie it to an action group?

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7 hours ago, royying said:

I think panther is more suitable for shuttle landing assist, it have better performance at high speed.

When the jet running at high attitude (high speed), it have higher efficiency, make the shuttle go further.

And the wide vector range help the shuttle pitch up at the last moment of landing

The down side of panther like lower ISP and heavier are not important for a giant MK3 shuttle

I can see that, but I generally prefer the engine to be as light and fuel-efficient as possible.  I use it primarily as a low-speed landing engine, where long-distance, high-altitude flight is not a priority.  If I am going to deorbit a shuttle, I can usually get it into the general area I want to land on, but I need to make some specific flight adjustments after reaching the lower atmosphere.  For example, while landing at KSC I find that I often either over-shoot or under-shoot the runway (shuttles and space planes can be especially variable when it comes to atmospheric deorbiting due to their lifting shapes and many possible orientations) so having the small engine to let me turn around or remain airborne longer are important.  If I can keep the mass (both from the engine and its associated necessary fuel) as low as possible, that helps and space mission it is trying to accomplish.  

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On 2/28/2017 at 0:11 PM, SickSix said:

I guess you have to tie it to an action group?

There's an option in the right-mouse menu in-flight to reverse the thrust, but if you have more than one then yeah, action group is necessary to avoid excessive yaw.

I think @Whisky Tango Foxtrot has it correct - It fills a niche that doesn't exist (yet?).  I have to say the only reason I use it is because it looks nice mounted on a nacelle with the circular intake for low-altitude craft. 

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3 hours ago, natsirt721 said:

I think @Whisky Tango Foxtrot has it correct - It fills a niche that doesn't exist (yet?).  I have to say the only reason I use it is because it looks nice mounted on a nacelle with the circular intake for low-altitude craft. 

I disagree, its a small niche, but it exists. #1) KSP is not just career mode, it fills a role people may desire in sandbox

#2) Its nice for island hoppers on Laythe. I had a laythe operation using two mk3 based aircraft: one was an SSTO with whiplashes and Rapiers that was harder to land, so I just brought it down at a nice flat near equatorial site, and used the craft with wheesleys to move the modules to other islands... but I used wheesleys and panthers - thrust reversed wheesleys with panthers on the back that afterburned for takeoff. The wheesley's allowed it to reverse, which was very nice.

ievBgHk.png

This was the base I had developed at the time:

YdLkhHt.png

but now with kerbal planetary bases, I have more complex bases that I can deploy from mk3 craft

Spoiler

NQaegvp.png

Module delivery from orbit:

VvAcAD5.png

An earlier test of a panther a smaller panther + wheesley based craft, note the thrust reversed wheesleys:

S3ocCzc.png

The bigger design in the first post uses inline intakes, and has wheesley's at the front of each nacelle, not just a single pair as in this design - those were primarily for backing up, but in the later design, they are also key to its forward thrust.

I was actually quite happy with the wheesley + panther designs. The ability to shut down the panthers and have the wheesley's thrust forward reduced landing distances considerably without requiring chute deployment (since I often moved stuff around with no kerbals on board to repack them). I could back it up if I didn't have space to turn around from going in the water/going into a steep slope/hitting the surface base that it landed next to. I could still cruise at around 500 m/s without afterburners, and faster with afterburners.... and for laythe at least, I could get it back to orbit if I really wanted to by loading a "rapier module"

U1zbiWk.png

I thought it looked cool having the cargobay spewing smoke :P

89QXJZ5.png

C5u6uKz.png

And... same concept for the enlarged design with 8x panthers, 8x wheesleys, and 4x rapiers from the module)

UsS564b.png

It would fly much worse carrying 40+ ton cargos without those 8 thrust reversed wheesleys. It would be much harder to move around on the ground without those wheesleys that could back it up or make it turn much tighter

Wheesleys are no help getting to another planet/moon and back, but if you want to play around with surface operations on laythe/a mod planet with an O2 atmosphere, then its great. I like doing that, its a fun challenge of designing a payload/surface craft for another planet that needs to be hoisted to LKO, transfered to Jool, and then deorbited and landed on laythe.

If I were going all stock, my laythe subs would use wheesley's too:

Spoiler

Deorbiting a rather heavy sub... I've also considered subs that have limited roving capabilities so that I can fill them with ore from a surface base:

iyRVt0U.png

bAMJVMl.png

v5ENaz9.png

fwSr4TR.png

6BxPah4.png

uY2JEIu.png

For an all stock version, use engine nacelles and wheesleys, design a surface "boat" that can refuel it (claw would be easiest rather than trying to line up docking ports)

 

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On 2/27/2017 at 3:48 PM, OrtwinS said:

Also, please keep the reduced reverse-thrust, it would be very weird if such an engine could generate the same thrust in reverse. The above mentioned ~70% sounds about right

I imagine that realistic thrust reverser values would be boring and useless from a gameplay perspective. Cosine losses alone should be around 29% based on my two minutes of wikipedia research. As someone who likes the wheesley, I'm fine with <100% reverse thrust.

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I'm fine with both values.... I used them when I thought they were/they still were 100% thrust in reverse - its a lot of thrust for a small frontal area, and great for supercruise designs. The panther is also great for supercruise designs if your design can get it to a speed where the dry panther performs better than the wheesley.

I'm not sure if I'd still use them this way because they surely have more drag than a nosecone of shock cone intake, and their effective Isp when reversed is less than 82% of the dry panther's Isp.

I'd probably just go with them all pointing backwards as they would in real life, and have separate nacelles for the panthers and the wheesleys.

70% thrust still allows for shorter landing rolls, powered turning on the ground (one side reversed, one side not reversed), and backing up - so I'll continue to use them even with the 70% thrust nerf to the reverser.

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Interesting to see the many uses for the Wheesley.  I've mostly ignored it except for building compact piloted Kerbin rovers before I have electric wheels.

Panthers, on the other hand, power my crew transfer/return space planes and a light cargo space plane carrying up to 5 tons in satellites or other cargo.  Especially useful for my first hard mode play through where getting to Whiplashes is taking longer than I expected.

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