Designing viable delta-wing'ed aircraft?

[tjsnh]

So a question for my fellow Kerbonauts.

First, I want to preface - I'm a pilot IRL, so KSP's aerodynamic controls tend to be a bit counterintuitive for me so in asking this question there's a chance that I'm simply doing something wrong.

My question is - has anyone discovered the engineering secret in KSP to making a delta-wing'ed aircraft controllable without canards? I expect with 0.90 and the Mk3 parts, delta wing'ed shuttles may get a bit more popular, though for the life of me I can't design one that has good vertical control (can't "pull up", even to take off, and even at 180+m/s).

Thoughts? Advice?

[Xavven]

Tilt your horizontal stabilizers *down* to move your center of lift forward. It may seem "wrong" to put any wing part in this state, as intuition suggest this creates negative lift (it doesn't when you nose up enough), but it is done IRL. This explains it better: http://en.wikipedia.org/wiki/Tailplane

EDIT: Here's the part that most applies: Depending on the aircraft design and flight regime, its tailplane may create positive lift or negative lift (downforce). It is sometimes assumed that on a stable aircraft this will always be a net down force, but this is untrue.

Also: In many modern conventional aircraft, the center of gravity is placed ahead of the center of pressure of the main wing.[citation needed] The wing lift then exerts a pitch-down moment around the centre of gravity, which must be balanced by a pitch-up moment (implying negative lift) from the tailplane.

Edited December 13, 2014 by Xavven

[EladDv]

i would suggest trying to have the CoM as back as possible and start the wings as forward as seems nice to you. from there it's a game of balancing CoM and CoL you engins are a good source of weight and shorter delta planes are more feasible

[Signo]

I managed a light design w/o canards, wings are a little bit oddly shaped as you can se below, I do not know if I can call it a proper delta. It works really really well (with NEAR too) and I hope I can scale up the design for something more than just reaching LKO and back.

Have you ever tried to use brute force rcs thrusters to nose up?

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[Van Disaster]

You may want to install the FAR mod if you haven't, it does a better approximation of air - and lets you assign different actions to different surfaces. Deltas work fine - I don't have many but this one is stable & controllable and doesn't get more delta-ish:

In stock or FAR it's mostly a case of balance, they're *very* sensitive to where the rear wheels are in relation to CoM.

[tjsnh]

I run pretty much stock, interesting thoughts on playing around with the CoM. I'll see if I can shift it backwards to see if that helps.

[Brofessional]

It's certainly viable, you just have to balance the CoM/CoL.

[Rune]

So a question for my fellow Kerbonauts.

First, I want to preface - I'm a pilot IRL, so KSP's aerodynamic controls tend to be a bit counterintuitive for me so in asking this question there's a chance that I'm simply doing something wrong.

My question is - has anyone discovered the engineering secret in KSP to making a delta-wing'ed aircraft controllable without canards? I expect with 0.90 and the Mk3 parts, delta wing'ed shuttles may get a bit more popular, though for the life of me I can't design one that has good vertical control (can't "pull up", even to take off, and even at 180+m/s).

Thoughts? Advice?

I know exactly your problem, and if you are a RL pilot you are going to hit yourself in the head when you read this: lever arm. You have most of your mass on the tail (engines), so you have a CoM close to the rear of the plane. Then you add control surfaces with a small lever arm. And obviously, they provide little torque. Now built a conventional tail and put those same control surfaces at twice the distance form the CoM (or put canards on the nose, much farther form CoM): suddenly you have twice the control authority.

Rune. And that's the reason big planes without canards have the engines in the wings and not the back, plus a long tail.

[Hodo]

So a question for my fellow Kerbonauts.

First, I want to preface - I'm a pilot IRL, so KSP's aerodynamic controls tend to be a bit counterintuitive for me so in asking this question there's a chance that I'm simply doing something wrong.

My question is - has anyone discovered the engineering secret in KSP to making a delta-wing'ed aircraft controllable without canards? I expect with 0.90 and the Mk3 parts, delta wing'ed shuttles may get a bit more popular, though for the life of me I can't design one that has good vertical control (can't "pull up", even to take off, and even at 180+m/s).

Thoughts? Advice?

One mod will solve most of your problems. Farrem Aerospace Research (FAR).

It will fix the souposphere of Kerbal Space Program and make it handle more like real air. So you will be a bit more comfirtable with it.

And I have built a few dozen delta wing aircraft all of which work extremely well.

F/A-106A Thundergod showing off at low altitude. It was 50m off the ground doing mach 1.2

Then there is this SSTO Delta wing design that I use as my medium lift workhorse.

There is this wonderful fighter SSTO.

Then there is this stock part design that uses a Mig-21 style delta wing.

[katateochi]

As well as the COM/COL positioning, I've found that where the rear wheels are is often the problem with take off. They really need to be quite close to the COM.

[MKI]

So a question for my fellow Kerbonauts.

First, I want to preface - I'm a pilot IRL, so KSP's aerodynamic controls tend to be a bit counterintuitive for me so in asking this question there's a chance that I'm simply doing something wrong.

My question is - has anyone discovered the engineering secret in KSP to making a delta-wing'ed aircraft controllable without canards? I expect with 0.90 and the Mk3 parts, delta wing'ed shuttles may get a bit more popular, though for the life of me I can't design one that has good vertical control (can't "pull up", even to take off, and even at 180+m/s).

Thoughts? Advice?

I generally part clip some canards in the nose. This gives the plane life in the front, and solves the control problems. At the same time it also gives the plane a much sleeker look.

So you get best of both words, otherwise you will have to design your plane with COM, COL, and torque in mind.

I've made a number of "Shuttle link" crafts, all with delta wings. Simply put to create viable Cargo Bay shuttles with delta wings(with the fuel in the back and almost nothing in the front) you have to either go light and use lots of torque or partclip some canards to control surfaces in on the front. Otherwise the ship will just be very difficult to fly.

I'm sure the new parts will probably provide enough reasonable torque to handle themselves. Especially after what we have seen and the fact the new MK3 Cockpit will be the LARGEST command pod in the game.

[Spatzimaus]

It's definitely possible, especially on small designs. On one of my old spaceplane designs I figured out that if you use wing components to place flaps BEHIND the engines, the distance from the CoM is equivalent to what you'd get from a front-mounted canard. Like so:

That cluster of winglets around/behind the jet engines is enough to get the torque you need for take-off, especially if your design is slightly up-angled to begin with (which mine are). Of course, it also depends on your CoM/CoL locations; I generally put the lift center slightly in front of the mass, which helps with takeoffs, although that does make landings more difficult as the loss of fuel will move the CoM even further back. (Nothing you can't fix by shifting a little fuel around before landing, though.)

That being said, there's no reason not to use canards up front. The trick is to not make them LOOK like canards; you don't need some extra winglet sticking out from your cockpit, looking all ugly. What you do is build them into the wing itself, like so:

(single pair of canards used to bridge the gap between the delta wing and the main body, in front of the intakes)

or

(four canards used to make a variable front slope to the body, above and below the main B9 intakes)

Both of these have the same effect as sticking a canard on the front of a design, without the loss in aesthetics you'd usually get.

It's not like large planes in real life don't have control surfaces built into the leading edges of the wings, after all. That's all this really mimics.

Edited December 13, 2014 by Spatzimaus

[qromodynmc]

It is all about balancing center of lift and center of gravity.

[Vanamonde]

This is a how-to kind of a question, and so, moved.

[tjsnh]

I know exactly your problem, and if you are a RL pilot you are going to hit yourself in the head when you read this: lever arm.

Yeah, getting a proper angle-of-moment on my control surfaces is a serious PITA with a delta design. I've played around with the COM a bit, relative to COL, by just adding some dead weight around the plane (which is otherwise light and flies great with canards) to compare results. The best I've been able to get is that the plane is able to climb .. a little ... after flying off the end of the KSP runway .. with FULL elevator deflection ... but the instant I let off the elevator, it's noseplant into the ocean.

[Turbo Dad]

This helped me a lot