[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18

[Guest]

@Dragon01: It is certainly possible, but I'd rather not; I already have plans to scrap the current wing code entirely, I don't want to put more work into it when it's all going to get trashed anyway.

Well, if it's not a 5-min change, then OK. I'll wait for the new code. Really looking forward to the overhaul, it'll be completely game-changing for all mods with weird wing shapes.

[etheoma]

One second I'm pretty sure the Frac SL Density uses kerbin sea level as reference isn't it?

Edited November 30, 2014 by etheoma

[etheoma]

etheoma: what you are consistently failing to realize is that the sea level density of Venus is not the sea level density of Earth. 0.1% of 110 is a lot more than 0.1% of 1.225!

erm the Frac SL density when you get down to the surface on a very big hill is 27.7... if it is 110 times the air density of kerbin then that mean the Frac SL desnity is different from on kerbin by 3.9711...

I flew on kerbin though an Frac SL density of 0.010 at 8k ms so I should be able to fly though eve at 0.002 I am getting ripped apart at 0.000 or 0.00049 <.

I'm also on what could basically be called a mountain so the Frac SL Desnity is not even out by 3.97x of kerbin atmos give the rise in desnity as you go down goes up exponentially its probably more like 2 x or 3x off.

Also give that the atmos also dissipates exponentially also given that I think its like 85 - 90 were the Frac SL Density reaches 0.001 which im pretty sure as I said is rounded from 0.00049 at 105km like the actual denisty is probably also more in the regions of 0.0001 to 0.0005

So where as I said 0.002 should be a safeish destiny I was more like as I said in 0.0001 0.0005 which is a safety margin of 4 - 20 times.

Also wile taking off 0.0005 from the what should have been save and also probably giving 2x 3x how far the Frac SL Desnity is off from what will show up on kerbin .

So its more like I was being anywhere from 5 to 40x saver than I needed to be.

Futher more I am also getting kicks to my craft in Duna's atmos which is thiner.

Its not ripping apart my craft but it is spinning me out.

Heres caft I managed to get down a little lower with infinite fuel things out the side are to make my centre of drag up top so I would land with the engine facing down.

Note Frac SL density is near 30 10km up

Edited December 1, 2014 by etheoma

[HoneyFox]

Oh one more request..... do you have any information for real aircraft like a F-16 or Mig-21 in the FAR diagnostic graphs and charts? I would love to see what a highly menuverable aircraft that is unstable naturally looks like compaired to a stable aircraft that doesnt need fly-by-wire controls to keep it in the air.

Check my post several pages back, there is at least a Cm curve of F-16 in that pdf.

[BadRocketsCo.]

Hello!

I have a small question: does it matter in FAR if you use conical fairings or egg shaped fairings?

[NathanKell]

Alas no. FAR cares only about start diameter and end diameter, and in both cases those are "0" and "the width of your stage".

[Hodo]

Check my post several pages back, there is at least a Cm curve of F-16 in that pdf.

I meant the numbers like in the Data-Stability tab in FAR.

[NastyEbilPiwate]

I've got an interesting problem where some of my crafts don't seem to have correct drag calculations. On re-entry the terminal velocity reported by FAR is way too high, and almost no drag is applied meaning that everything overheats and explodes because the craft isn't slowing down (I have Deadly ReEntry too). For simple designs like a Mk1-2 pod and a heatshield hyperedited into a decaying orbit, drag works fine but when using some parts (not sure which yet), the whole ship's drag calculations seem to be wrong. I'm pretty sure I've used the same mod parts before 0.25/the most recent FAR and they worked fine then.

Any ideas what might be wrong? I'm going to keep trying to narrow down what part(s) it could be.

[Starman4308]

I've got an interesting problem where some of my crafts don't seem to have correct drag calculations. On re-entry the terminal velocity reported by FAR is way too high, and almost no drag is applied meaning that everything overheats and explodes because the craft isn't slowing down (I have Deadly ReEntry too). For simple designs like a Mk1-2 pod and a heatshield hyperedited into a decaying orbit, drag works fine but when using some parts (not sure which yet), the whole ship's drag calculations seem to be wrong. I'm pretty sure I've used the same mod parts before 0.25/the most recent FAR and they worked fine then.

Any ideas what might be wrong? I'm going to keep trying to narrow down what part(s) it could be.

Are you clipping the heatshield into the pod? If you do that, it really confuses FAR's drag calculation. The entire heatshield model should be outside the pod, such that its top node connects to the pod's bottom node; if you connect bottom-to-bottom, you get weird drag issues.

[NastyEbilPiwate]

Are you clipping the heatshield into the pod? If you do that, it really confuses FAR's drag calculation. The entire heatshield model should be outside the pod, such that its top node connects to the pod's bottom node; if you connect bottom-to-bottom, you get weird drag issues.

Nope - the design I'm seeing the issue on is a plane with no heatshields or overlapping parts of any kind.

[Wanderfound]

Alas no. FAR cares only about start diameter and end diameter, and in both cases those are "0" and "the width of your stage".

Speaking of which...the second Rockomax adaptor in this pic is generating a lot of drag:

Is having it there doing me any good at all, or would I be better off just running the 2.5m lab straight into the Mk2 parts with no attempt at smoothing the transition?

Also curious as to why it appears that engines create more drag than intakes.

[NathanKell]

If you want to be a Cheating Cheaty Cheater you can just not use adaptors at all, since FAR doesn't see flat area unless there's an open node.

[Guest]

We really need Mk2 to 2m adapter. I've had an idea involving this, but the only one available is from B9. B9 is nice and all, but it's still using the old Mk2 standard.

[ArcFurnace]

We really need Mk2 to 2m adapter. I've had an idea involving this, but the only one available is from B9. B9 is nice and all, but it's still using the old Mk2 standard.

Lucky for you, looks like that's planned for stock in the next version (look at the far right of the picture):

[Van Disaster]

Design question:

What's the recommended way of bringing down takeoff/landing speeds for high-speed wing shapes? it can't just be "flaps" because some of these shapes go well past CoL and that'd be a rather large pitching moment. "More wing area" is not always practical either. Some particular shape tweak?

I did this thing partially to investigate:

A little low area perhaps but not totally out of scale - however it refuses to unstick until 108m/s despite being pitched up on it's wheels slightly, and obviously landing is about the same if I want to retain pitch control & not just gently crash into the runway. Col/CoM are overlapping, once it's unstuck it's extremely responsive and the only derivative error is a roll/yaw couple I'm not too concerned about.

[Hodo]

It is possible to take off and land at about 75-90m/s with a delta wing design.

Here is a great example of one that can do it.

And this one.

The trick is actually finding that right wing scale and gear placement to get the perfect rotational speed to take off and land.

The problem I was running into was getting them to slowdown for landing. So I added a drag chute from Real Chutes for landing that acts like a landing chute to cut down the braking needs on landing and runway distance. I can land the first and second craft quite easily on the island strip in about 3/4 of the runway with minimum of braking.

I love the deltawing design, and have been using it for a long time, it is simple and stable. It does have some minor problems but the way to solve most of them is the same way that the Russian firm Sukhoi did with the Su-17. They setup a specific designed wing that would generate good lift at supersonic speeds without much drag, and yet still had the lift at low speeds to reduce runway take-off length.

The same principles work here in FAR.

[NathanKell]

If you have low enough wing loading, you can get by with quite high sweep. The issue, as Hodo says, is adding enough wing (KSP parts are deceptively dense) and placing gear well.

[Van Disaster]

Yeah, that delta has rather less area than Hodo's first - I had a feeling it was mostly wing loading ( come to think of it, can we get a wing loading entry in the properties list please? ), I usually add rather more than is really needed unless it gets physically awkward to do so, but this time I wanted to get a feel for shape ( and also keep things in proportion ). It'll lift the nosewheel fine, just takes a lot of speed. Ground-effect would help a delta a bit, not sure that ever made it in in the end?

Drag chute was about the first thing I reverted to add after I noticed the takeoff roll...

[werk62]

Hodo, which mod does the cockpit for that black jet come from? It's exactly the style of cockpit I have been looking for!

[Van Disaster]

RetroFuture mod.

Full of interesting goodies, including it's own pWings ( although I'm using repainted original pWings ).

Oddly, adding wing area without shifting CoL ( or CoM ) hasn't changed behavior at all.

Edited December 2, 2014 by Van Disaster

[werk62]

Thanks! This part pack looks amazing!

[Surefoot]

Ground-effect would help a delta a bit, not sure that ever made it in in the end?

Last time i asked, Ferram told me it was not implemented. But that was at least one year ago...

[BudgetHedgehog]

Last time i asked, Ferram told me it was not implemented. But that was at least one year ago...

I remember seeing a more recent quote from him along the lines of 'too much work for not enough gain'.

[Hodo]

Yeah, that delta has rather less area than Hodo's first - I had a feeling it was mostly wing loading ( come to think of it, can we get a wing loading entry in the properties list please? ), I usually add rather more than is really needed unless it gets physically awkward to do so, but this time I wanted to get a feel for shape ( and also keep things in proportion ). It'll lift the nosewheel fine, just takes a lot of speed. Ground-effect would help a delta a bit, not sure that ever made it in in the end?

Drag chute was about the first thing I reverted to add after I noticed the takeoff roll...

Oddly enough the nose wheel on mine lifts pretty easily it just wont come off the ground till it gets to around 90m/s then it lifts off fine. Now the F/A-106A lifts off at 75m/s everytime, and flies great, but it has a bit more wing to it.

The deltawing is by far my favorite wing type, I have even recently made larger SSTOs that use the same wing shape.

60 ton cargo.

150ton cargo

40-60 ton cargo

All of which are VERY capable SSTOs and some of them, like the first one when empty take off at 70-80m/s.

[Guest]

When was that cockpit added to B9?