Why can't I get to a high altitude?

[larry909]

Even with planes that should be able to!

 

Here's a link to a YouTube (youtu.be/9msns5qaYnc ), not mine, but exactly what I experience when trying to fly high. The F-18 hits 27,000 feet and just stalls.

[ScatterbrainKid]

I'm more of a low and slow bush flying simmer so I'm not an expert in high altitudes apart from the odd dabble, but these threads should give you some clues, it's to do with IAS, TAS and Mach etc-

 

https://www.flightsim.com/vbfs/showthread.php?286117-Higher-altitude

 

https://www.flightsim.com/vbfs/showthread.php?291507-Afterburner-Thrust-Relationship

 

https://www.flightsim.com/vbfs/showthread.php?287393-Speed-limits

[mrzippy]

Got your Pitot Heat on?

[CptCaveman]

Got your Pitot Heat on?

 

^This. Fighters are heavily affected by ice on the pitot and wings. Make sure your heaters are on.

[PhantomTweak]

I never have any trouble getting the FSXBA F/A-18C up to a cruise at 42,000' MSL, Mach 0.84. Then again, I turn my pitot heat on as a matter of course at the end of the runway.

It will zoom-climb from 50' AGL, 350KTS to about 25,000'MSL, 45° pitch. Get the bird just up off the ground, pull up the gear and flaps, and keep it in Mil power to 350 Kts, which doesn't take very long at all. Above around 25,000' MSL you have to lower the nose to about 15° for the rest of it to maintain your climb at about 0.75 Mach.

All this at Mil power, not AB. You go AB, you can go up a bit faster.

Does all this help any?

Pat☺

[larry909]

Thanks scatterbrainedkid, good info. I will also check the pitot heat

[COBS]

The problem can also stem from the technique that you apply to get to a high altitude.

 

Even the SR-71 Blackbird doesn't just climb to it's high cruise altitude , it performs a series of steps to get up there.

It climbs part way up then flies level to accelerate , then dips the nose a little to further accelerate , then when the speed build up is sufficient it pulls the nose up through the horizon line to climb.

As the energy bleeds off the speed reduces , it then levels off and repeats the above process until it reaches cruise altitude.

 

With the F-111 , I tend to climb to medium altitudes of 25,000' to 35,000' , then level off and accelerate to supersonic speed and ease the nose up into a climb , then level off at 50,000' to 60,000' , at 60,000' you need to be gentle with the controls as the air is thin , the autopilot will fly it at that altitude , but you get a slight bobbing up and down as it works hard to maintain level .

At 25 to 35 thousand feet , I level the F-111 and accelerate to Mach 2.52 , then pull the nose up to the absolute vertical and hold it vertical in a zoom climb , on various occassions I have got it up to 140,000' before the energy and speed bleeds off to zero and it then tumbles and falls back down.

 

The important aspect is energy , and that is determined by airspeed , you need the speed to climb , and importantly you need to maintain a minimum speed to continue a climb , eventually you will reach an altitude/airspeed where the only option is to level off or fall off.

 

Cheers

Karol

PS;

140,000' is over 5 times as high as in that F-18 video.

the skies are a velvet black , and full of stars , delightful to see.

[larry909]

Thanks COBS! Where do I find the pitot heat switch in F-18?

[ScatterbrainKid]

I can't find a hotkey labelled 'Pitot heat' in the key assignments list, maybe I need new glasses, but I did find this one-

 

Carb Heat/ Engine Anti-ice on/off- H

 

But I haven't a clue where the switch is in the F/A-18 cockpit

[il88pp]

options-settings-display

 

aircraft tab

 

check mark in the box: show tooltips.

 

then try all vc buttons ;)

 

(it's somewhere on the right, next to your knee/thigh.)

[PhantomTweak]

The Pitot Heat switch is on the Righthand control panel, just outboard of the seat's SAFE/ARM switch. Please see pic below.

 

Key combo is SHFT+H.

Hope this helps :D

Pat☺

[larry909]

Found it.

 

Got up to over 70,000 feet!