XR5 problems

[HiPotOk1978]

I am going to assume that the XR5 does not suck cause I don't see any posts saying it does and I accept I don't know what the heck I am doing

My failed mission with the XR5 was as follows

take 321.5 tons of cargo from ReFuel HQ on Earth to Refuel Lunar Facility. I loaded up the cargo using UCD. My flight path to LEO was a follows.

Use rocket engines to 20km engage Scrams. Power down rocket engines as scrams become more efficient. Use scrams to build HVel and raise altitude to avoid burning a hole though the hull. Hull temps during last attempt were 1000+C during the entire supersonic and hypersonic climbs. Shutdown scrams when A) fuel is exhausted or B) diffusers overheat. In this last attempt, I got overheat warning right as I was burning the last of the fuel, use rocket engines to finish orbital insertion. This is where I get stuck. by the time I get a stable orbit I currenty have about 3.8% left in the tanks, nowhere near enough to break orbit and enter Lunar orbit. so what am I doing wrong.

Help Help Help

 

[V8Li]

I haven't used the XR5 but my guess is that you are too low and too fast. Keep the Dynamic Pressure (Surface MFD or the XR5 gauges - probaly has) to 20 KPa. If you can't have full control over the ship increase it to 30 or so. That will give you minimum drag/velocity ratio.
PS: what's the altitude at which you are shutting down the SCRAMs?

 

[HiPotOk1978]

I haven't used the XR5 but my guess is that you are too low and too fast. Keep the Dynamic Pressure (Surface MFD or the XR5 gauges - probaly has) to 20 KPa. If you can't have full control over the ship increase it to 30 or so. That will give you minimum drag/velocity ratio.
PS: what's the altitude at which you are shutting down the SCRAMs?

I am burning the scrams well into the upper mesosphere, so 80km+

 

[dbeachy1]

Since you are carrying 321 tons of payload you will need more fuel than normal to reach orbit; you can edit your Config\XR5VanguardPrefs.cfg file and set 'MainFuelISP=3' as shown below:

#--------------------------------------------------------------------------
# Main Fuel ISP ("Specific Impulse") setting. This determines how much
# main/hover/rcs fuel is burned each second for a given thrust level.
# Higher settings allow longer flights without refueling. Remember to
# update the 'LOXLoadout' value later in this file as well so the crew will
# have enough oxygen for the mission!
#
# NOTE: The 'Expert' setting (0) is tuned so that you will need to use your SCRAM engines
# efficiently during ascent to LEO ("Low Earth Orbit").
#
# NOTE: these settings below are calibrated for *minimal payload in the bay*, so if you
# carry a heavy payload you may have to bump up your fuel setting to the next higher setting.
# The ISP setting for each level is shown in [brackets].
# 0 = Expert (ISS Only w/expert use of SCRAM engines and expert deorbit/landing) [13943]
# 1 = Realistic (ISS Only) [20914]
# 2 = Default (ISS and Moon) [25962]
# 3 = Medium (ISS and Moon w/reserve) [32981]
# 4 = Medium+ (Moon w/large reserve) [40000]
# 5 = Big (Mars) [52922]
# 6 = Huge (Jupiter+) [366251]
# 7 = Massive (Jupiter+ w/full payload) [549377]
#
# The default value is 2 (ISS and Moon).
#--------------------------------------------------------------------------
MainFuelISP=3

If you still run out of fuel, just set the 'MainFuelISP' to 4 or 5.

 

[HiPotOk1978]

Since you are carrying 321 tons of payload you will need more fuel than normal to reach orbit

Wow, I got Doug to respond to me :speakcool:

thx for the info, I will be editing the file for enough O2 to get me to my Ganymede base. Gotta get fuel to Jupiter for sales somehow... and your plane is so much fun.

I thought I read somewhere in your documents that came with the craft that 480 tons was the max cargo weight to orbit, or was that 480 tons I can lift off the runway w/o ripping the wings off. What is your MAX cargo weight w/o refueling to do a Earth to Moon run btw, cause well moon runs are fun

If this prob I am experiencing is "By Design" then I'd rather just arrange an orbital refuel instead of editing the plane to make the engines burn what fuel I carry with me more efficiently.... Your crafts are about realism right?

Oh, I have experienced a few other problems as well since I got your attention:

I used the Shuttle ET for the mesh and attached it to your craft via Sputniks Velcro Rockets as an external tank. I had no problems cept one... Even with the engines off, I still consumed fuel like the engines were running at 100%... Is this some special code that also prevents you from using the scn editor to add fuel on the fly? I was thinking I could fly another XR5 up and use the 20t SSBB on the airlock to refuel before TLI, but that didn't work with FuelMFD for some reason... Fuel was just not pumped.

Cheers!

 

[TSPenguin]

This is from the XR2 but it is similar to all XR Vessels and should explain your refueling problems. It does not explain your fuel leak though, I've never heard of something like that.

#--------------------------------------------------------------------------
# Enable or disable Orbiter's default auto-refueling behavior (i.e., when
# touching down on a landing pad.)
#
# You should set this value to 1 (Orbiter auto-refueling enabled) only if you
# want to use an external refueling MFD (such as FuelMFD), or if you want Orbiter
# to automatically and instantly refuel you when you touch down on a landing pad.
#
# If you will only be using the XR2's built-in refueling features, leave
# this value set to its default of 0 (Orbiter auto-refueling disabled).
#
# 0 = Orbiter auto-refueling disabled (recommended)
# 1 = Orbiter auto-refueling enabled
#--------------------------------------------------------------------------
OrbiterAutoRefuelingEnabled=0

I can highly recommend reading through the whole config file. You will discover a lot of cool features you would otherwise probably miss.
Also Doug is a very caring developer and answers all threads regarding his vessels :speakcool:

 

[dbeachy1]

I thought I read somewhere in your documents that came with the craft that 480 tons was the max cargo weight to orbit, or was that 480 tons I can lift off the runway w/o ripping the wings off. What is your MAX cargo weight w/o refueling to do a Earth to Moon run btw, cause well moon runs are fun

432 tons is the maximum recommended payload mass for the Vanguard; the ship can actually carry more, but landing, ascent, and reentry are difficult with excess payload mass.

I used the Shuttle ET for the mesh and attached it to your craft via Sputniks Velcro Rockets as an external tank. I had no problems cept one... Even with the engines off, I still consumed fuel like the engines were running at 100%...

The problem is almost certainly that another add-on is draining fuel from the Vanguard's tanks; the Vanguard does not consume any fuel when the throttles are closed.

 

[TSPenguin]

the Vanguard does not consume any fuel when the throttles are closed.

...AND you are not dumping the fuel...

 

[HiPotOk1978]

432 tons is the maximum recommended payload mass for the Vanguard; the ship can actually carry more, but landing, ascent, and reentry are difficult with excess payload mass.

quick question for Doug or anyone that has done this... What is the max payload that u can take to the moon w/o editing anything and keeping with the XR5's default settings and not refueling in LEO

 

[itchythemouse]

the fuel draining problem could be caused by the velcro tank
it depends on how you attach it to the XR5, if you use the crossfeed function
it should not leak fuel and the tank should function like a drop tank.

 

[docabn]

I have been having problems getting into orbit with enough fuel to manuver much myself. I would be interested in anyone who can explain the proper use of the scram engine. ( I need it dummed down a bit I think).

I can only get to the point where I can reduce thrust but never more than below 25%, I tried leveling out more to gain speed while maintaining enough atmosphere to run the scram but ran into the same issue you did of hull tempuratures exceeding 1000 C.

I will continue to practice but if anyone has a really good set of instructions that would be cool (Yes I did read the PDF manual that came with the XR5)

 

[HiPotOk1978]

this is an old thread but i will reply to it... I would recommend reading when the last post was... er posted before adding to it...

As far as your problem...

It takes practice getting into a perfect orbit using a SCRAM assisted craft such as the XR1, 2, 5, and the stock DG with SCRAM engines. Finding that proper speed and altitude combo when your carrying weight.

I have no scientific approach to this but as I am climbing in altitude and velocity I am watching hull temp, scram temp, altitude, dynamic pressure, as well as fuel reserve.

What I try to accomplish is a full throttle SCRAM ascent exhausting fuel as high as I can with the scram temps as close to red line as I can get them w/o a failure of the engine. I accomplish this by constantly adjusting my pitch creating a step like ascent with long horizontal travel and slow vertical ascent path. Your going to be in the mesosphere once your scram fuel is depleted so your use both your main rocket engines to achieve speed for SCRAM start then transfer back to them for the final orbital insertion. if I can get 60-70km altitude with a mach number near 20 I feel I have done a good ascent.

With my Morning Star add-on package that turns a XR5 into a giant flying refueling ship, the cargo bay has over 500 tons of extra weight in the form of main engine fuel. Doing an ascent with the refueling payload in the bay and taking off from my surface base in Tucson flying a heading of 90 deg, I am usually much lower in altitude and if I exhaust the fuel after leaving the east coast of America I consider that a sucessful SCRAM ascent.

Remember even NASA had to learn how to fly in space and like NASA there is nothing wrong with launching flights with the sole purpose of learning the craft. Experimentation with various profiles and slower or faster ascents is how I learned.

 

[docabn]

sorry about getting off topic, but thanks for the advice.