Flight Question Unless there is a senario "Fly me to the moon" you just cannot fly into orbit?

[Carmen A]

A great way to learn how to do an orbital ascent and interception is to try it from the Moon. There's much less gravity and the Shuttle A will get to orbital speed in literally a minute. It's a great way to familiarise with the instruments, orbital maneuvering terminology & controls, and when all else fails you can even do a radio/visual intercept by locking on a target's docking port signal (DockMFD).

While inefficient, the mere experience of locking on and getting in formation with an orbital target will allow you to grasp the priniples of trajectory planning in a practical environment on a smaller scale.


Then, for Earth launches, simply ride shotgun on rockets and the Shuttle on autopilot, go through the shuttle's manual for the launch procedure and achieving orbit should then be pretty easy even on the 'realistic' fuel loads and engine capability.

 

[Izack]

I'm pretty sure the stock delta glider is capable of reaching escape velocity by pointing straight up and burning the tank dry...

Test result:

Used the scenario "DG-S ready for takeoff" and went vertical right off the runway.

 

[PhantomCruiser]

Oh yeah, it can be done, but that's not what he's wanting to accomplish. And you must admit it doesn't leave a whole lot of fuel for TLI, LOI etc.
With the other methods presented he's left with 1/2 tank (or more).

I must admit, it is kind fun though.... Can you imagine the radio chatter?
"Delta-Golf-4-1-4 cleared to orbital on the numbers"

 

[Carmen A]

"Unrestricted climb" mode might not get the ship anywhere but my suggestion to newbies is... just do it anyway. The 'feel' of suborbital flight is enough to convince new pilots to try out more advanced and efficient launch profiles.

Heck, all space programmes started off suborbital or even... from ballistic missiles.

Plus, unrestricted climb is fun. Just imagine the C17 is an XR5

 

[Roger55]

That was interesting. Well there I was. 454 fuel left and an orbit that wasn't an orbit, but a parabola. Houston I caused a problem, a big problem. I guess that I might as well eject and open my helmet. I'll starve after about a month anyway. Mission control regrets . . . .

 

[PhantomCruiser]

:rofl:
Groovy dude! Don't beat yourself up over it, it just takes some practice. Mad Skills aren't developed overnight (unless your single, no kids, no school, no mortgage, no job or no life...).

 

[Roger55]

Well that describes me. No anything. Not even a dog since August.

I also cannot sit in front of the computer for hours any more.

What I did was see the orbit was enlarging but turned to the HUD, and looked to long. Then swiched the controls to ROT. When I killed the engine it was too late. Try again later.

---------- Post added 01-07-11 at 02:43 PM ---------- Previous post was 01-06-11 at 07:54 PM ----------

I've been reading the Getting into Orbit thread. The fellow seems a little hostile but the thread is full of good information. One thing I am NOT saying is the the the in atmospheric flight model is wrong. In a flight sim like FS9 you have planes that are dead easy to fly (DC-9) and some aerobatic planes that are touchy-touchy. The NYP Ryan is just a bad design. Full of gas it can be a fight to keep it straight on th runway and whip over the power line and not end up in the trees. In flight it needs constant attention. And if you fly NYP you can stand those 34.5 hours in about 2 hour sessions. It gives you a new aprreciation of what a pilot Lindberg was.

The point is that AC are different; so, who expects the DG to handle like an F-86? The DG is one of the tough ones.

I think the biggest probem (after holding a heading) though is knowing when the DG loose all lift and needs to be switched to ROT control (I was switching to the wrong controls).

Now let me admit a dirty secret. Because I have to read the manual from the screen and have yet to find someone of some place to print the thing, I have to fight the inevitable headache:facepalm: to get through it. So like NYP I have to take it in increments. Even the author's helpful things to read are PDF files. Whoever started this PDF trend (and Kindle and all such nonsense) must have been determined to drive book readers insane.

So todays Question is How about the book: It's Only Rocket Science by Rogers, as backgrolund to all that astrophysics that you say we neophytes to know. Especially for someone who studied Late Roman History and Medieval English Literature and whose last Calculus and Trig classes were in HS 40 years ago.

---------- Post added at 04:23 PM ---------- Previous post was at 02:43 PM ----------

This is turning into a monologue.

I took off in the dark when the plane of the Earth's orbit and the Moon's matched on the Map projection. I took a slow ruway run and got off at the end (red warning lights). But I maintained control and came to 90 degrees (East). Then I began to climb slowly increasing throttle. She drifted up to 90 degrees and the heading began to change. Paying attention to the Orbit MFD. Too high, I eased he down to 30. Then she began to drop. Trim diddent keep her out of the negative climb: switched to ROT and got her up to ten. The APA began to climb with the heading drifting 110 degrees (ESE).

When I stoped trying to correct the heading the APA wa 239 K. Nuts! Kill the engine! PEA was -4.59 AP was comming up pretty fast. Turned prograde and waited. Fired at AP.

Took forever to get PE out of the negative. When I stopped. APA 1.381 M, PEA 235.4 k, Ecc .0798. Not so good. Obviously, added too much energy.

You know something I just noticed. I think I left the gear down. Have to go check the Quick Save.:rofl:

 

[Mantis]

Why don't you try this....download and install the Delta Glider IV addon (available from Orbit Hangar Mods). DGIV has a built in launch auto-pilot that will fly the spacecraft into a perfect orbit on the specified heading. It will get you into orbit and while the computer is flying the spacecraft, you can watch and observe the correct procedures for achieving orbit. In all honesty, the Deltaglider is one of the easiest spacecraft to fly and to reach orbit with. It carries a lot of fuel, has an extremely powerful engine and handles quite easily. I suspect that you are just not grasping the basic concepts. Watching the DGIV fly itself into orbit on auto-pilot will give you a live demonstration of that process.

 

[Hielor]

Now let me admit a dirty secret. Because I have to read the manual from the screen and have yet to find someone of some place to print the thing, I have to fight the inevitable headache:facepalm: to get through it. So like NYP I have to take it in increments. Even the author's helpful things to read are PDF files. Whoever started this PDF trend (and Kindle and all such nonsense) must have been determined to drive book readers insane.

There's nothing stopping you from printing the manual...

 

[Roger55]

There's nothing stopping you from printing the manual...

Except the lack of a printer. The Second died a year ago.

Now everyone isn't going to read this but I have a problem. I became, over the years, agoraphobic. I fight it every day.

I have a really hard time going to different places even if they are almost empty.

Most equipment comes in here via UPS or The USPS. I can think about going to Office Max, or Walmart or Kinkos but it can take weeks for me to try to get the car out of the drive but it's touch and go when I try it.

It is completely illogical and very embarassing to panic at the edge of your own diveway.

That's why I don't rush out this minute and get it printed. Feel free to ROTFLOL. Most people do.

I think I'm done here.

 

[Hielor]

Except the lack of a printer. The Second died a year ago.

Now everyone isn't going to read this but I have a problem. I became, over the years, agoraphobic. I fight it every day.

I have a really hard time going to different places even if they are almost empty.

Most equipment comes in here via UPS or The USPS. I can think about going to Office Max, or Walmart or Kinkos but it can take weeks for me to try to get the car out of the drive but it's touch and go when I try it.

It is completely illogical and very embarassing to panic at the edge of your own diveway.

That's why I don't rush out this minute and get it printed. Feel free to ROTFLOL. Most people do.

I think I'm done here.

I'm not rotfloling.

You could always buy a printer online and have it delivered...

 

[PhantomCruiser]

It sounds as if you are starting to get the hang of it. Keep up the practice, it'll get easier and eventually become a non-event.
As mentioned, the DGIV comes with a really good autopilot program that will put you into orbit hands-free. Worth the download. Maybe sometime at night since you are on dial-up. But still worth it. The DGIV is one of the Orbiter "staples" that should be in your collection.

 

[Roger55]

Attachment didn't work. Nuts.

 

[Adelanthal]

Took forever to get PE out of the negative. When I stopped. APA 1.381 M, PEA 235.4 k, Ecc .0798. Not so good. Obviously, added too much energy.

For a first successful orbit, that's really not too bad. Only thing I can see that you did wrong was fired too close to APA. If you've got the quicksave from before the APA burn, try burning ~30 seconds earlier and see how that works out. But it seems that you've got most of the basics down, just down to refining.

Granted, there's ALWAYS something else to refine. But that's most of the fun of Orbiter. Good luck.

 

[jthill]

at about 30% power

Why are you using anything less than full throttle? Hold KP-ENTER, tap CTRL, release. No touchie till MECO, which you do with KP-*. Part-throttle is for very fine control, e.g. that last km or two of rendezvous timing.

Mild spoilers follow:

===


To maintain efficiency just control DNP with VAcc (manual then trim once you get it all stable above the boundary layers, gimbal too if you're into maximum efficiency), keep DNP about 10, definitely below 11, to start. Being able to control DNP with a very light touch is important. If it starts dropping out of control, your DG will shortly follow suit. Doing that produces the book's initial 70-75deg climbout. You can turn very efficiently during that climbout, don't turn before climbing because it spikes your DNP, effectively jamming a sock in your exhaust nozzle.

Finding a nice trim setting for initial climbout will cut your workload dramatically.

 

[Roger55]

Here's the Orbit.

 

[Tommy]

You can turn very efficiently during that climbout, don't turn before climbing because it spikes your DNP, effectively jamming a sock in your exhaust nozzle.

Static Pressure - not Dynamic Pressure is what "jams the sock in the nozzle". Trying to turn before you climb - while under full throttle - causes excessive airspeed at a very low altitude. At 280m/s, at under 5k alt - the DG will generate a drag force of almost 7 m/s. In other words - it's not the thrust that reduces - it's the drag that increases.

That's one of the reasons I recommend reducing throttle after wheels up - drag increases quite dramatically once you exceed 250m/s at low altitude. the other reason is that trying to turn while holding a very high pitch angle is tricky for beginners. It's easier to get the heading aligned while "cruising" at about 225km/s and 3k alt - then worry about the actual ascent.

Also, I've given it some thought and think I know why you are having trouble with the DG rolling so much. Most ascent tutorials have you going to high at too low velocity. This makes the aero controls less usefull - and also reduces the wings ability to stabilize the vessel and counter rotational inertia. The ascent profile I gave earlier is designed so that this is greatly reduced and the DG will be more "Stable" during the ascent.

One thing I forgot to mention is that your heading will change during the ascent. Don't fight that - it's natural and desired - just try to keep the wings level.

 

[Roger55]

Quote :"Also, I've given it some thought and think I know why you are having trouble with the DG rolling so much. Most ascent tutorials have you going to high at too low velocity. This makes the aero controls less usefull - and also reduces the wings ability to stabilize the vessel and counter rotational inertia. The ascent profile I gave earlier is designed so that this is greatly reduced and the DG will be more "Stable" during the ascent.":thumbup:

Bingo! The vertical stabilizer on a jet is relatively larger than this flying wedge and even at full power (certainly nowhere near what two rockets can do) you will fall off. If the atmospheric flight model is anywhere near reliablble those ailerons are too small to control the DG at top speed. I got it lined up at low altitude and then went. The tutorial shows an angle of attack of 30 degrees. The Auto pilot on the DGIV show a 50 degree angle.

My heading when I got to the place I needed to turn on ROT 110 degrees. The reasoin I started to drop is that I did not notice the loss of control. I seem to be very bad at that. I need to start watching for an altitude.

Any comments on that orbit, like, Oh, how to fix it? :thankyou:

 

[Hielor]

Static Pressure - not Dynamic Pressure is what "jams the sock in the nozzle". Trying to turn before you climb - while under full throttle - causes excessive airspeed at a very low altitude. At 280m/s, at under 5k alt - the DG will generate a drag force of almost 7 m/s. In other words - it's not the thrust that reduces - it's the drag that increases.

Static pressure is dependent only on altitude. Dynamic pressure is the indicator of drag, since it's also dependent on speed.

 

[jthill]

Any comments on that orbit, like, Oh, how to fix it?

Looks to me like you've achieved the basics just fine, what's left is just a matter of training and managing your focus. You'll find in your reading that you most efficiently fix apogee (apoapsis when not specifically orbiting Earth) at perigee, fix perigee at apogee, and fix orbit planes at the slowest node (where your current and target orbit planes intersect) you can find.

Achieving rendezvous, let alone dock, with the ISS is a huge step. Expect it to be hard. I still have the screenshot from my first successful rendezvous somewhere, and I don't need to see it to recall the satisfaction, even pride.

The reason I started to drop is that I did not notice the loss of control. I seem to be very bad at that. I need to start watching for an altitude.

Altitude by itself doesn't tell you anything, you have to know what planet you're on and how fast you're going to get any useful information out of altitude.

Dynamic pressure is a much more direct measure of aerodynamic authority. No DNP, no control. VAcc controls the rate at which DNP changes. Once you're above the boundary layers a fairly efficient hands-off ascent has VAcc oscillating slowly near zero, more above than below, and DNP dropping very slowly.

Since Tommy and I achieve near-identical efficiency I'd just assumed our methods were similarly similar. Apparently not. Interesting.