Standard Cruise Configuration?

[cruster]

The BAe 31/32 is an excellent product, Javier. Thanks for making it available! I have a quick question and I'm hoping you know the answer off the top of your head and won't have to type for an hour and a half.  What is the correct cruise configuration for this bird?

 

I just flew about 300nm across the middle of Africa and managed to average about 255 kts ground speed (225-230 kts indicated) at FL160, which is great, in light of the fact I was only burning about 100 gal/hour. However, the prop RPM was initially laying right at 100% but eventually creeped up to the white triangle (103%, lower limit of overspeed governor, IIRC). EGT was also just about 640, with % torque around 65-70%.  

 

Pulling the RPM levers back about 1/2 way to the "Taxi" mark didn't seem to have any effect on Prop RPM as far as the gauge was concerned, BTW. I think I remember reading in the manual that "Flight" was 100% prop RPM and "Taxi" was 72%, so maybe there's not a lot of adjustment there to start with. In retrospect, I don't think the prop RPM climbed past 100% until after I turned off the TTL computers (past FL140).

 

Am I setting things (close to) right?

[Japo32]

Hello!

 

I think they just fly normally at FL150-220 or so, but I have heared here total flights at 5000ft.

Still the fuel consumption has to be better defined. To to it lots of flights has to be done. I tested several to match close to the real one.. but it is very difficult to find documentation about this. The only way is know the range of the plane and fly to match that range at cero wind speed. Changes will come in future updates I guess.

 

about the not change of the RPM with change of the condition lever ratio position. well the real one only have 3 positions and there are no reasons to put in the middle, Down, Taxi and flight. Maybe in future I just make a click to just put the lever in those positions only. 

In planemaker is really difficult to achieve a number of RPM at a certain position of the condition levers. You can set the number but other thing is what the engine does in xplane.. because depends in several situations. 

My principal purpose was to be near the numbers.. but specially in the 100% torque area independently of the position of the thrust levers. 

But yes.. as said.. I have planed several little modifications inside the flight dynamics of the plane. Which I must say that I am happy with them.

Edited December 19, 2012 by Japo32

[hiddenace]

Javier to piggyback this thread what are the speeds for this bird T/O and Landing 

[Cameron]

Javier to piggyback this thread what are the speeds for this bird T/O and Landing 

 

This will vary depending on a number of factors. While no charts are published, please consult the manual for speeds and use your best judgement depending on the configuration of your aircraft. Page 9 is there for your reading pleasure.

[Intrance]

At 1000' AGL you usually set climb power... Reduce torque until you get about 550C EGT (but don't go lower than 80%) and reduce RPM to 97%. Flip on prop synch if you want and reset power levers to get your desired rate of climb or max. 650C EGT. Climb speed should be 160kt IAS until FL150, after FL150 reduce with 3kt for every 1000ft. Then during cruise, just keep RPM 97% and temp below limits, or adjust for fuel economy .

 

During summer, be happy to get above FL100 with max weight. In winter you can probably get up to FL200 without too much trouble. Service ceiling is FL250, but so far, the highest I have flown is about FL190 on a 2+ hour flight. Shorter hops (about 1 hour or less) are mostly FL130-160. In the summer this can give you about 1-5 minutes at cruising altitude . Also, for some very short hops (10 mins or less) we just fly at MSA.

 

About T/O and LDG speeds:

 

Depends on a lot of factors indeed. Mostly weight and and flap setting. My company has a quick reference on the checklists that starts at 5600kg which will give you speeds of 99, 101 and 111 (V1+Vr, V2 and Vy Single Engine). Up to maximum takeoff weight of about 7050/7350 (31 or 32), which gives speeds around 112, 115, 125.

 

Vref for 5600kg is 101 (flaps 35) or 111 (flaps 20). During approach 130-140kts is a nice speed, any lower and in the real aircraft the controls will get a bit more sloppy.

Edited December 20, 2012 by Intrance

[hiddenace]

At 1000' AGL you usually set climb power... Reduce torque until you get about 550C EGT (but don't go lower than 80%) and reduce RPM to 97%. Flip on prop synch if you want and reset power levers to get your desired rate of climb or max. 650C EGT. Climb speed should be 160kt IAS until FL150, after FL150 reduce with 3kt for every 1000ft. Then during cruise, just keep RPM 97% and temp below limits, or adjust for fuel economy .

 

During summer, be happy to get above FL100 with max weight. In winter you can probably get up to FL200 without too much trouble. Service ceiling is FL250, but so far, the highest I have flown is about FL190 on a 2+ hour flight. Shorter hops (about 1 hour or less) are mostly FL130-160. In the summer this can give you about 1-5 minutes at cruising altitude . Also, for some very short hops (10 mins or less) we just fly at MSA.

 

About T/O and LDG speeds:

 

Depends on a lot of factors indeed. Mostly weight and and flap setting. My company has a quick reference on the checklists that starts at 5600kg which will give you speeds of 99, 101 and 111 (V1+Vr, V2 and Vy Single Engine). Up to maximum takeoff weight of about 7050/7350 (31 or 32), which gives speeds around 112, 115, 125.

 

Vref for 5600kg is 101 (flaps 35) or 111 (flaps 20). During approach 130-140kts is a nice speed, any lower and in the real aircraft the controls will get a bit more sloppy.

It's funny you say that because it acts just like that in X-plane good to finally get some one with real experience to answer some questions.

 

I had another question. is the real airplane really as squirmy as it is in xplane. I find it hard to maintain altitude and heading because the plane feels like i'm always on the backside of the power curve if you know what i mean

[Intrance]

It's funny you say that because it acts just like that in X-plane good to finally get some one with real experience to answer some questions.

 

I had another question. is the real airplane really as squirmy as it is in xplane. I find it hard to maintain altitude and heading because the plane feels like i'm always on the backside of the power curve if you know what i mean

 

No, it's quite stable in real life, provided it is trimmed correctly. If you don't have bumpy weather and the trim is set, you can basically lean back for a bit and it will fly as though on autopilot.

[pmorris]

Thanks Intrance good information to have.  Javier seems to have got the performance spot on.  Landing above 120 kts (flaps 35) there is a strong tendency to balloon and below about 100 kts to stall.  Inside the range and all is well.

[cessna729]

what are the speeds for this bird T/O and Landing

This may be of some help.

http://www.aftd.com/TCDS_PDFS/A56EU_5.pdf

Airspeed Limits.

VMO (Maximum Operating Speed) up to 16,750 ft 250 knots,

VMO (Maximum Operating Speed) at 25,000 ft 210 knots

VA (Manoeuvering Speed) 180 knots

VFE (Flaps Extended Speed)

Take-off (Flaps 10°) 170 knots

Approach (Flaps 20°) 160 knots

Landing (Flaps 35°) 150 knots

Lift Dump (Flaps 70°) 120 knots

VLE (Landing Gear Extended Speed) 160 knots

VLO (Landing Gear Operating Speed) 160 knots

VMC (Minimum Control Speed)

Take-off (Flaps 10°) 100 knots

Note: VMC at sea level/15°C standard atmosphere condition. See FAA-approved Flight Manual HP.4.16 for other conditions.

cessna729.

[cruster]

I appreciate the info/guidelines from all of you. My first couple of flights in the -32, I felt like a test pilot. There was a lot of "Hrmm, I guess it doesn't respond well to control inputs below about 105 kts" and "Stalling it onto the runway with the stick pusher engaged is not advisable" going on.

Putting the props at 97% is an interesting comment, though. As I explained in my first post, I put the RPM lever at "Flight" (100% setting) and leave it there, as it doesn't seem to do much otherwise. In my last flight, I observed the same behavior, in as much as the prop RPM sat at 100% through takeoff and most of climb, but then floated up to the 103% triangle for the rest of the flight. This time I did not disable the TTL computers above FL140, just to see if that was the culprit. It wasn't.

For me, the process is: RPM lever to "Flight", flaps at 10%, power up to wherever I can get it while keeping the EGT below 650. Rotate around 110, climb at whatever rate happens until I get everything cleaned up and the AP engaged, then dial in 2000 FPM. From that point on, I use the Power lever to manage EGT. For cruise, I keep the EGT just a hair under the 650 red line and everything seems OK, speed and fuel-burn wise.

At TOD, I set and arm the altitude selector, hit VS and dial in appropriate FPM (I've been going around 1200-1500, depending on airspeed...airspeed / 2 * 10 rule of thumb, with some adjustment based on gut feel) then use the Power lever to manage airspeed (below the green/white mark). Once I hit pattern altitude I juggle flaps and power and try to stay up around 150-160 kts, otherwise I feel like the plane is made out of rubber (no crispness to the controls at all). Once established, I drop the gear, power up a bit to offset the drag and try to put it on the ground in one piece. Oh, and up until Intrance's post, I had only been using two notches of flaps on approach. I'll give it max next time and see what happens.

My next 'test flight' (haha) I'll actually try to land with the stick pusher disabled. That can be disabled by clicking on the glare shield lights, even if the lights aren't illuminated, right?

[Japo32]

RIght, you can press them even the lights are not illuminated. 

Right now thinking how to make in programming the stick pusher to be softer and gradually.

[cessna729]

I'll actually try to land with the stick pusher disabled. That can be disabled by clicking on the glare shield lights, even if the lights aren't illuminated, right?

Yes, check my rough vid on JS-32 stalling. http://forums.x-pilot.com/index.php/topic/4231-solved-elevator-madness/#entry43617

cessna729.

[cessna729]

Putting the props at 97% is an interesting comment, though. As I explained in my first post, I put the RPM lever at "Flight" (100% setting) and leave it there, as it doesn't seem to do much otherwise.

The following is from "bits" of a very old crew manual. (might be a slightly different Mk from the one Javier has modeled).

Flying for Best Altitude.

To acheive best gross preformance the RPM should be set to 100%. the power lever should be advanced to Redline torque or Redline EGT whichever comes first. the aircraft should be flown at the Single Engine EnRoute Climb Speed. The setting of the air conditioning flow selectors is quite critical in achieving the best performance, so use as "low" a flow as possible to just maintain cabin pressurisation.

Flying for Best Range.

If altitude is not critical, the following procedure should be followed - this will give improved aircraft handling and a small improvement in range. Set the RPM to 97%, set the Power levers as in "Flying for Best Altitude", fly at 140kts, set air conditioning flow selectors as in "Flying for Best Altitude". Once the aircraft has stabillised, especially at lighter weights, it may be necessary to reduce power to maintain an airspeed of 140kts.

cessna729.