PDA

View Full Version : Question on possible planes we would like to see added before the deadline.



crashaz
December 11th, 2009, 10:46
Just trying to get an idea on what types of - in my case warbirds- we would like to see that would help out performance and distance wise with a new ride?


Any ideas?


I have a FSX P-61 in the shop... not sure if it's performance envelope would be beneficial to RTW?

PRB
December 11th, 2009, 13:03
Well, the slowest warbird in the racing hangar is probably dcc's P-38. It can make 360-ish knots (ground speed) at its critical altitidude of 25,000 feet. Pretty much every other warbird used can get over 400 GS. Of course everything depends on the set of rules they throw at us this year, but based on past years, the P-38, being a forgiving and easy to land airplane with decent range, is probably the slowest plane people might choose. That said, a P-61 would be awesome! Not sure how fast it is though.

srgalahad
December 11th, 2009, 16:48
IIRC ( it's hard to think while sitting 200 ft from the surf with a couple of cervezas in me) Fliger's mod for the RTW of the Ito P-61 had --- good range, a bit slowish in the climb, a Stuka-like descent and about 390-400 TAS. Good enough for the masses and a descent flyer.

Other than that, the problem is that most of the fast (legal) warbirds have been done - in FS9. There are a few that were as quick and not modeled but most don't meet the rules of 10 units in service, etc. Now, for FSX the list is longer (see what hasn't been ported/created that is good in FS9).

crashaz
December 16th, 2009, 21:06
Well I am interested to see how tesing of the new FSX P-38 goes. I can volunteer as I have it.

What should I be testing?

Dangerousdave26
December 17th, 2009, 12:57
Best climb profile

Speed (TAS) @ critical altitude

Range at critical altitude

Test under no weather conditions.

Engine damage? Yes/No

Any thing else that might be special to the model.

Screen Shots :icon_lol:

srgalahad
December 17th, 2009, 13:19
and, since it's a relatively new model, a comparison to some real-world #s would support it's accuracy. Doesn't have to be perfect, but too-much-too-hot and it might raise eyebrows, although it still won't be a Do-335 beater.

Spookster67
December 18th, 2009, 01:14
Best climb profile
How do you measure that? I assume the "best" isn't the steepest, because although you get to critical altitude quickly, you have very low ground speed while climbing.

When I've been looking at aircraft options I reckon the Vne speed is important (I think that's the "max_indicated_speed" in the aircraft.cfg file). Being able to descend steeply/quickly certainly helps.

srgalahad
December 18th, 2009, 08:57
How do you measure that? I assume the "best" isn't the steepest, because although you get to critical altitude quickly, you have very low ground speed while climbing.

As a general 'rule' the longer the leg the more advantage there is in speed; on shorter legs climb performance is the key. That's why -in the 2008 race- some of the Cabin Class a/c were often almost as fast on Duenna time (300nm legs) as many of the fighters in tests.

The first thought is to reach your best altitude and speed ASAP to spend the longest time at top speed with the most efficient fuel burn. However some aircraft have poor climb performance when loaded, and others accelerate slowly. My preferred test method is to:

1. determine the optimum cruise altitude (remember winds will ultimately play a part in the race). Perhaps slightly above CA may be best as it will give a bit more range for a small loss of speed but that can be adjusted enroute.

2.Determine the highest sustainable climb rate (fpm) - some a/c will climb fast initially but then have to be eased off significantly as you get higher to maintain speed.

3. Fly a few tests using a stopwatch or timer and DME for distance. Measure how long & far it takes to get to altitude at max rate - then keep going and measure how long and far until you accelerate to max speed. Make notes. (note: some feel that climbing slightly above and then descending to cruise altitude helps you accelerate - scientific testing has not come up with a universal answer)

4. Repeat the tests using a lower rate of climb/higher airspeed (say 20% different) and compare the two. In both cases note the amount of fuel used to get to cruise.

Now, you use science or intuition! In many cases the differences will be small, but in a few it can be significant - compare the results. Small differences can be compromised by erratic flying or weather so don't fret the small stuff. Ballpark numbers are around 200KIAS in the climb for fighters (dccs P-38 may be a bit lower but at a higher rate of climb, for example), 150-170 KIAS for things like the DC-7, 210KIAS for large jet tubes (but many require a step-climb until fuel burns off before being able to reach optimum altitude).


When I've been looking at aircraft options I reckon the Vne speed is important (I think that's the "max_indicated_speed" in the aircraft.cfg file). Being able to descend steeply/quickly certainly helps.

Because this is "racing" and not totally realistic (we don't care about pax - just don't overspeed or overstress), descent can be a big difference. A/c with a lower Vne have to be planned (can you watch the airspeed as you descend thru cloud, keeping the needle just below Vne? and leaving room for gusts?) - you may have to start a more gentle descent, further out and sacrifice GS as you get lower. Higher Vne allows a faster (and often steeper descent allowing longer at cruise speed/altitude. A high Vne plus "aids" such as dive flaps or spoilers are even better... but remember you also have to slow to gear/flap speeds which can sometimes take a while.

Once you find a couple of "good" aircraft in each group, practice, practice, practice so the techniques come naturally.. and have a Post-it note with critical speeds in front of you for reference when you race.

The ultimate answer is "block time" (aka Duenna Time) so that's your confirmation... fly several a/c and/or flights to see what comes out fastest.

(then again, some people pick planes because they fly nicer, easier, safer :icon_lol: -- and the last is the true test - crashes are deadly)

Rob

bpfowler
December 18th, 2009, 20:00
how does the corsair fit in this mix? I have some experience with it, largely in approaches and landing rather than distance.

it's a solid climber, but would the f8f be a better ride for this run?

Dangerousdave26
December 19th, 2009, 05:29
how does the corsair fit in this mix? I have some experience with it, largely in approaches and landing rather than distance.

it's a solid climber, but would the f8f be a better ride for this run?

The Corsair is too short on legs unless it has drop tanks.

Most of us who use the Corsair use Aeroplane Heavens Night Fighter version with filger747's modified airfile and aircraft.cfg.

While I have the Donationware Corsairs I have never tested their range/speed with the tanks.

The F8F is a solid performer if you get the long range version by Oldliner52. The standard Bearcat does not have the range and has actually bite us once.

With the Bearcat you must keep an eye on your range or you could run out of fuel.

The Bearcat has an extremely low Critical Altitude going slightly over CA will increase your range at the cost of speed (like most aircraft).

Keep in mind the Corsair and the Bearcat are both Tail draggers.

Spookster67
December 19th, 2009, 05:36
The ultimate answer is "block time" (aka Duenna Time) so that's your confirmation... fly several a/c and/or flights to see what comes out fastest.
Thanks for the detailed response, Rob. It's about as I guessed - not really a scientific measure, just test different climb rates and see what works.

I tend to start with a gentle climb to build speed, then pull up into a steep climb, but keep an eye on indicated airspeed. If that starts to fall too much, then push down again to maintain speed, but accept a lower climb rate.

Dangerousdave26
December 19th, 2009, 05:51
Thanks for the detailed response, Rob. It's about as I guessed - not really a scientific measure, just test different climb rates and see what works.

I tend to start with a gentle climb to build speed, then pull up into a steep climb, but keep an eye on indicated airspeed. If that starts to fall too much, then push down again to maintain speed, but accept a lower climb rate.

To establish the best climb profile I tend to almost the same but I watch GS along with indicated speed.

If the ground speed is increasing as you climb it should mean you are not climbing so fast you are losing or holding back forward momentum.

If I am not doing a straight out flight then I will turn on the proper heading at a lower climb rate to build up airspeed. Once on the proper course I climb at the desired rate for that aircraft.

RFields
December 19th, 2009, 16:48
The ultimate answer is "block time" (aka Duenna Time) so that's your confirmation... fly several a/c and/or flights to see what comes out fastest.

Please remember in the race - the two hour time limit is based upon the forum date/time stamp on the "I have the baton" and "The baton is free" posts.

But also Rob points out the most important element - practice, practice, practice.

Speed of aircraft helps, but during the RTW the team with the fewest crashes almost wins. We are approaching the point where we might see a team finish the race with no crashes.

It takes a lot of high speed runs in the P-51 or other fighter to make up for a 30 minute crash penalty.

srgalahad
December 20th, 2009, 06:51
Please remember in the race - the two hour time limit is based upon the forum date/time stamp on the "I have the baton" and "The baton is free" posts.

Reggie's right (of course :icon_lol: ) for the race.
My reference to the Duenna time should only be taken in the context of testing total time from Start to Landing in a flight test mode as that will show the parameters for the entire flight (take-off, climb, cruise, descent, landing and braking) to evaluate aircraft.

Rob