Basically what it says on the tin, there are tons of numbers out there for the high-speed cruise (Mach 0.76) but that only gets you to 2000 nmi. The full NBAA IFR range of the aircraft is 2165 nmi, but I can’t find anything saying what speed that’s at. (Figured I’d ask here since the “Default Aircraft” category seems to have some stuff happening to it.)
Simbrief generates a long range cruise speed for the WT CJ4 of about M.62, TAS about 350, at FL410. The normal cruise speed generated for the same flight was M.75, TAS 430. I seem to remember the same numbers from a discussion on their Discord server a while back.
How do you get SimBrief to generate long range cruise and normal cruise speeds?
under “Advanced Aircraft Options”, see the Cruise Profile selection drop down.
1 Like
Huh. That’s… a bit interesting. The one source I could find on long-range cruise (this here) says that the optimal is at FL450 and 375 KTAS.
Is there a specific Simbrief profile for the WT CJ4 anywhere? The default one doesn’t seem to be giving out either the numbers you gave or the numbers that source gave.
The test flight I happened to use was an eastbound flight which is why it was limited to FL410. Westbound at FL450 should give better performance.
You can get a Simbrief profile for the WT CJ4 from Working Title CJ4. Scroll down a bit and you will see the link for it.
Yeah I found the profile.
My flight is also eastbound (PHTO to KSFO, about 2100 nmi so it should be able to make it) but it keeps saying “flight time exceeds aircraft range” even when I set the cruise to FL450 manually (is there a limitation on eastbound flights that prevents them from going that high?) and with a 16kt tailwind, which I think is a pretty obvious warning. Not sure what I’m doing wrong.
Somewhat related, would you happen to know what the best glide speed for the CJ4 is? That usually sits somewhere around the point of minimum drag, and I’d like to have a rough estimate of where the “back half” of the drag curve (where slowing down increases drag) starts.
1 Like
Now that you mention it, I don’t know why Simbrief gave me FL410 for my flight. Above FL410, 2000 feet of vertical separation is required so FL410 is eastbound, FL430 is westbound and FL450 would be eastbound.
Best glide speed will be roughly halfway between Vx (best angle of climb speed) and Vy (best rate of climb speed). That’s assuming you are looking for max distance travelled. If you are looking to just stay in the air longer, the speed is a little less. I don’t know the exact numbers off the top of my head but my guess is that it would be somewhere around 110 kts or a tad higher.
Would the contingency fuel potentially be messing with it? I shouldn’t need contingency fuel if there’s a known tailwind, and it’s loading somewhere around 250 lbs for that. When I got rid of that it stopped giving me the range error.
Letter of the law says that on an IFR flight plan you need enough fuel to make it to your destination plus an additional 45 minutes at normal cruise plus enough fuel to make it to your alternate if an alternate is required due to weather conditions. However, this being a sim, you can ignore all that if you wish. 
I’ve got reserve and alternate fuel in and it works fine with those. The “contingency fuel” seems to be something different, that’s why I figured I could get rid of it.
So something very strange has happened with this flight plan. Despite having a slightly higher ISA and a few knots less tailwind than Simbrief predicted, I’m managing to cruise faster than the numbers it gave me to use while also burning less fuel than what it predicted. Any idea what could be up with that?
Topic moved into 3rd Party Aircraft for discussion. #third-party-addon-discussion:aircraft
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.