crj 200 climb performance

[filipo]

The crj 200 is not the best at getting up to altitude..but with higher than standard temp say isa +17 is it efficient to climb at speeds less than 250kts to attain altitude much quicker?
:confused:

[flyboyike]

ISA+17, ouch! I don't think climbing at 210 will help you all that much. Firstly, at higher weights 210 may be a tad too slow for comfort, secondly, rather than gaining much climb performance you'll probably just hurt your groundspeed.

If you're flying ship 7011, tell her hello for me. Oh, and I left my pen in there, too.

[filipo]

if then 210 kts is rather not productive and thus will not fly a sustain climb passed Fl250 they why certify it for Fl 410.
looks like with a paltry 8000lbs...its not meant for high altitude say past Fl 350. but I reckon there is a way to make it efficient within its meagre firepower

[Capn Bloggs]

why certify it for Fl 410
Probably because a lot of the areas of operation for which it was designed are not at ISA+17...

[flyboyike]

Indeed. Keep in mind also that certification numbers presume a brand new airplane, brand new engines, test pilots at the controls etc. At ISA + 17, I doubt you'll see anything much above FL310 at normal weights.

[galaxy flyer]

Certification isn't performance. That is, just because it met the F410 cert standards doesn't mean it has to perform there.

[Lord Spandex Masher]

test pilots at the controls etc.

Are test pilots so good that they can bend the laws of physics?!

[C_Star]

This report contains all you need to know about climbing the CRJ to FL410:
http://www.ntsb.gov/doclib/reports/2007/AAR0701.pdf

[flyboyike]

The laws of physics don't apply to test pilots. In fact, no laws do.

[rogerg]

I took a light CRJ200 to FL410 to try to climb above CAT. It was very uncomfortable. I didn't stay there long.

[WeekendFlyer]

In simple terms climb performance for shallow climb angles is calculated as follows:

Rate of Climb = [(thrust - drag) x TAS)]/weight

where TAS and ROC have the same units of speed (kt, m/s, fps, or whatever you choose)

or, put another way, approximates to:

TAS x [ (thrust/weight) - (drag/lift) ]

You set the best lift/drag ratio by flying at the speed for minimum drag. This will vary slightly with weight but does not change with thrust. Therefore the "best climb speed" is what it is. You fly it and you get the best climb rate because you have the best available L/D ratio. If you increase speed to try to get a better climb rate, the drag increases and thus you don't get the gain in climb rate you might expect.

The biggest factor in the equation is Thrust/Weight ratio. If you are at MTOW and it is hot outside (ISA + 17) then with the best will in the world your T/W ratio will be poor, so your climb rate will be low. To get a better rate all you can do is take off at a lower weight. Even the best pilot in the world will be constrained by the equations above.

The only way you could get around this, would be to do a series of diving accelerations, each interspersed with zoom climbs, converting speed to height in several steps. It can be more efficient but I expect ATC might have something to say about it in busy airspace!