VTOL post-1.0?

[KristopherKerblumbus]

Okay, so obviously my first admission is that I'm using B9 parts, which are currently on "WIP" status, and I don't know how much that has to do with my problem. If that's the case, say so and I'll go on my merry way. But I think I just haven't figured out 1.0.4's flight physics yet. In .90, I was able to build 747-size orange-tank VTOL atmospheric airplanes that I was going to use to drop parts for base building. Then, 1.0 came out, and now I can't even get something like this to lift off. I've got KER, so I know the stats I need (1.0+ TWR in the vertical direction, plenty of reaction wheels and a balanced CoM/CoT), but I'm just having no luck. Does anybody have any tips? Thanks!

Edited September 5, 2015 by KristopherKerblumbus

[peachoftree]

What exactly is causing it not to lift off? does it not get off the ground, flip over, or something else? Some screenshots or a video would be extremely useful here.

[KristopherKerblumbus]

Sorry. I thought I was clear enough in the OP. I've tried a number of different designs, so screenshots really *wouldn't* be helpful. My problem is that I can't get anything off the ground. I guess my question is if the post-1.0 B9 jet altering configs reduce the thrust such that nothing lifts, and again, I'm using KER, so I understand the basic ideas and have the stats to check what works and what doesn't, I'm just unable to get anything to lift unless I use a ridiculous amount of engines (e.g., three Sabre-M engines on a Mk. II cockpit, one 8m fuel tank and a bicoupler)

[JTpopcorn]

I assume by lifting you mean vertical takeoff. If so, a screenshot of your craft would help. Also, KER should be able to show the TWR of a given stage, and if that is less than 1 there is your problem. However, engines have fun thrust curves based on speed and altitude, so I assume that at a standstill the Sabre's can't lift the plane because they are most effective in upper atmo and space at high speeds. Right click on the engines once launched to see their actual thrust at rest.

[KristopherKerblumbus]

http://i.imgur.com/UDPylPG.jpg This was the first thing I tried, posted in the OP. It was a longrange science and exploration craft that served me well pre-1.0. Now, post 1.0, that won't get off the ground. Nothing will. Even when I shrink it to less than half the size and strip the wings off just to test the VTOL portion. I can get HTOL planes off the ground fine. Just built an HL-size SSTO that can go up to a 200km orbit easy.

[Claw]

Well, static thrust for the jet engines is greatly reduced. I don't know about KER, but I know MJ doesn't really give good TWR for jet engines. I'm not sure what it's using for a baseline, but that might be the issue you're running into. KER might think you're putting out more thrust that what's actually coming out.

Unfortunately VTOLs did indeed take a big hit because of this. Also, the CoM location on jet engines is problematic for VTOL craft.

I haven't built a lot of VTOLs in 1.0, so hopefully someone with more recent experience will stumble in, but I have also found VTOL craft harder to work with in 1.0.

It might be worth simply spamming jet engines all over and seeing if you can get it to lift off. Just to make sure there isn't something up with your mounting technique or some other phantom thing in the way of the engines.

Cheers,

~Claw

Edited September 5, 2015 by Claw

[panzer1b]

I see you are trying to use basic jet engines for liftoff in VTOL mode, dont even waste your time, those engines are now WORTHLESSLY underpowered in every department, garbage thrust, especially liftoff thrust, very heavy, and they seem to not gain thrust until you are moving at high speeds.

Currently your best bet would be turbojets for the VTOL portion, those have the best thrust when immobile, and their mass is insignificantly more then the basic jet.

Really the basic jet is SO BAD ive been avoiding that one for everything these days, it cant do jack anymore (in 1.0 it was at least useable at lower speeds, now its so bad its worthless at any speed).

Hopefully the devs will take a good look at 1.1 and balance, so we dont end up with as many worthless parts (there are too many engines right now that are redundant or just purely underpowered). Really the sole use i have for the basic jet are boats where the ISP matters, and the bad thrust isnt a big deal as you cant go too fast or you explode.....

Just try to swap your VTOL system for turbojets, they are better thrust and can actually lift some stuff into the sky, the basic jets are useless unless you are playing career and actually want to do something on kerbin.

[KristopherKerblumbus]

Well, that's part of it I guess. I was using basic jets because they throttle up so quickly, and I try to use as few as possible because I like aesthetics. But if jets just took a huge hit and it's not just me, I'll just see where I can go from here. Thanks for all the help guys, I'll consider this answered

[percyPrune]

Using basic jets I now have to double up on the number I used in 1.0.2 and, even so, TWR is quite marginal and the extra engines add a weight penalty. Like you I still use them though because of their reaction time (and aesthetics). Another downside is that they are serious gas guzzlers now!

This just gets off the ground with 4 lift +2 forward engines and full fuel load:

Only solution is "Moare h'enjins"!

Edited September 7, 2015 by percyPrune

[I_Killed_Jeb]

The only reliable way to get a true TWR readout with jet engines with KER is to launch the craft and get the in-flight readout of TWR (look at the denominator).