Thanks for that BendyFlyer, could I share a link I've found if you haven't seen it already?
https://www.scribd.com/document/11327612/C46-Manual#
This is the Pilot Training Manual for the C-46 and appears to be contemporary with late WW2 operation as it directly references the Hump flights in its foreword.
Tom
__________________________________________________ ___________________________________________
Wisdom is the principal thing; therefore get wisdom: and with all thy getting get understanding. Proverbs 4:7
ROFLMAO
Today, I got the email.
Sue
Yeah it seemed to me that although on paper the service ceiling may be somewhere in the 22-24K' range can't imagine it was practically flown there...so you're talking being at the half way point of the max altitude with a plane where the turbo critical altitude was prob in the FL160 range...so the 2-300 FPM climb seems accurate without ever looking at a performance chart...
MACH 3 DESIGN STUDIO
Heatblur Rivet Counting Squad™
FWIW and for those who would like to actually enjoy this aeroplane, because it is a challenge for various reasons, a lot of unreal expectations to begin with, I am reproducing a few notes I put on the JF Forum for the C-46 and thoughts on flying the C-46:
"I am not sure what environment some people are trying to operate this aeroplane. What is the ambient outside temperature at your take off point and what is the elevation of the aerodrome? These are very critical issues with this and any aeroplane's performance.
....As previous posts have stated this aircraft was always underpowered for its size and weight. It was notorious for its lack of climb rate (Rate of climb is a function of excess power over weight) even under good conditions it would normally not climb any better than about 100-250 fpm with a full load. The aeroplane may have had a book service ceiling of about 24000 ft but that is the ceiling at which the aircraft can no longer climb more than 100 fpm. This would have been done from sea level on a cool or standard ISA day (+15C). All performance data was based on the standard ISA day. Every degree above this reduces the performance. Aerodrome altitude is also important, the higher you are the worse the performance, hotter day higher airfield and you are already losing a lot of performance.
The normal cruise altitude for this aircraft was about 6000ft not high altitudes. The aircraft was notorious for not being aerodynamically stable at or above 16000ft, it ran out of power to keep the margin between the stall speed and cruise speed at a safe level (its called coffin corner).
Yes it was used on the Hump but that was a decision based on its volumetric capacity and the need to transport a lot of stuff, it used a hell of a lot of fuel to do it and was despite carrying almost double the load of a C-47 it used so much fuel the reality was only a 24% gain in load. If your going to do the Hump in this expect to fly round in circles to get any altitude before going anywhere and do more circling enroute once fuel burned off to get higher.
The aeroplane is fine at low altitudes and is good into and out of short strips (with a balanced field length of about 2500ft required). This was its forte and a reason it got a new lease of life with Air America etc in Vietnam.
It is what it is a big heavy underpowered twin piston engined aeroplane. It is not a high altitude flyer and it is not a good aeroplane to poke about in high mountains and high terrain. Despite all that it was a nice aeroplane to fly, it was comfortable, not too hard to operate and reliable. The C-47 would outshine it on just about any level except how much you could stuff inside. It is what it is - the Curtis C-46 Commando.
OK here's what a very experienced C-46 pilot has to say about flying this bird:
"There were never any certified V-speeds on normal C-46s. No "blue line," no Vmc, V1, V2, Vx, Vy, etc. Many chief pilots couldn't live with this, so they conducted their own rough testing, and picked some speeds that worked well enough, and with which they could browbeat trainees and checkees. But anyone who uses them is kidding himself, and possibly developing a dangerous thought process. Having published "V-speeds" also means that a "V1 cut" is required on check rides, and I've had quite enough excitement in airplanes, thank you very much, we don't do those, anymore. Without published V-speeds, the FAA does not allow even the simulated failure of an engine in flight below 500 feet on a check ride.
The old manuals usually call for a "minimum safe single engine speed," and it's generally around 95 knots, or "close enough," and that's what we use.
(Some C-46s were heavily modified, and certified under the old CAR 4b for transports (Everts has one working on a Part 121 operation, today!) Those do have true V1 and V2 speeds, along with appropriate charts. Those speeds are NOT good to use in the unmodified aircraft.)
Under CAF and FAA rules, we use full rated power (2,000 HP, 52", 2700 RPM) on ALL takeoffs, regardless of weight, a very good idea in ALL piston-powered airplanes.
With just a little help with forward elevator, the tail wants to come up around 40 knots or so, and with a little experience, we learn and hold a fixed attitude, slightly tail-low.
Somewhere around 80 knots the airplane obviously wants to fly, and we let it do so, holding the attitude at which it lifts off. The moment the airplane is off, that 80 knots instantly becomes 88 knots, as there is a built-in error in the pitot system when in ground effect.
Still maintaining the liftoff attitude, we allow a gentle climb and a gentle airspeed increase, and we accelerate to 95 knots. With that, and only when positive there will not be ground contact, pull the gear. Pulling the gear is the signal to everyone in the cockpit that we will continue flying with an engine failure. Before that, we'll probably put it back down. We continue to hold that same liftoff attitude and accelerate to about 105 knots, then pitch up gently (VERY gently) to hold that speed. Jet pilots have a LOT of trouble with this concept, and invariably they will haul the airplane off the ground and "rotate" to a nose high attitude as they do on the job. That is DISASTER in any old prop airplane, for the performance is simply not there.
(There is also NO SUCH THING as "Vr" or "Rotation" in a prop airplane! That is strictly a jet certification term, and has several very specific meanings that do NOT apply to props! I always get a chuckle out of the idea of "rotating" any prop airplane, especially something like a Cherokee.)
The Climb
As the gear comes up and the situation stabilizes at around 105 knots, we usually call for the first power reduction, to "METO" (Maximum Except Take Off) power, or 44" and 2550. When heavy, we'll delay that a few more seconds, to help gain altitude to protect from an engine failure.
At about 300 feet when light, or 500 feet (or more) when heavy, a second power reduction is usually used, to 36" and 2300 RPM, or "Climb Power."
105 knots makes an excellent pattern speed during the climb, and in level flight. The airplane seems to like that speed, using about 25 inches of manifold pressure and 1800 RPM on downwind, level. Any faster speed tends to overrun other VFR traffic in the pattern, and slower than 105 knots brings on problems with an engine failure. Trainees will almost always lose 10 knots while they struggle with the airplane, and while 95 is fine, getting slower will cause control problems with one engine at high power, and one windmilling."
I have emphasised a couple of very important handling issues here - the first is your aiming for 95 knots basically in level flight or about 2 -3 pitch up (not much is it) to get to about 105 knots before climbing, there is no use of flap and it all takes time the speed increases are actually very slow from 88 to 95 is only 7 knots to 105 is only another 10 knots all this time you need to be basically only slightly pitch up and then and only then will it begin to climb and very slowly, similarly with acceleration it is as the pilot politely described 'gentle'.
So it is a matter of technique with this bird. For those interested the minimum field length to clear a 50ft obstacle (a tree or fence) is usually about 4500 -6000 ft, so if your trying to shoehorn it out of a tight spot or do not have that minimum amount of distance in front your going to collect something before you get going.
Once its flying its fine you just can't chuck it about like a fighter or a light twin, smooth and gentle all the way and you will be rewarded. Push it hard and it is going to frustrate the hell out of you.
I will admit there are some issues still to resolve with the gauge coding etc, but I am confident this will happen and I am glad that it was done and I like it a lot. Best place to fly it - Alaska down low or anywhere else down low, take it into the hills expect to have some excitement.
C-46 service pack 2 is now available - https://www.justflight.com/support/c46-commando/c3a4681
Changes include:
- FDE improvements
- Flight 1 GTN 750 integration added to modern cockpit
- NAV/GPS switch added
- Glideslope indicator in military cockpit fixed
- HSI instruments fixed
- OBS compass rings fixed
- Radio tuning issues fixed
- Magnetos, generators and ignition still on after using cold & dark switched - fixed
- GPS backlight flickering at night - fixed
- Co-pilot ADI texture issue - fixed
Thanks
Martyn
Martyn
Just Flight Development Manager
Thanks Martyn---much appreciated.
Has the FDE in the SP2 changed,or is the version C46@151117 the same?
Mike
thank you Martyn..
Well, the new fde does add power. I find that beneficial if not realistic. See, I fly out of Kunming a lot. The alt. there is 6300 feet, so using real numbers, the plane couldnt even make it off the ground there.. The new fde allows it to climb out from there with little issues beyond losing some stability above 120 mph.. It's a good plane.. the only question i would have is: "How do you turn the brightness down on the kns-750??? its far too bright to see clearly..
With this new update, under P3Dv4.1 I'm unable to start the engines. They start, then die. Even with CTRL-E autostart. Under FSX, they start fine manually or automatically.
Copying back an aircraft.cfg and C46.air file from the previous version (SP1) restores the engine start - but of course leaves off the FDE improvements.
I'd expect a refresh to the SP2 coming soon, unless I'm the only one seeing this.
Dutch
Is there a way to taxi this thing with the rudder and not dif wheel braking/throttle inputs....!?!?!
I do not have the hardware to use dif braking and individual throttle quadrants for a twin!!!
Cheers,
Tim.
Hmm, think I'll wait on this update. If it aint broke, don't fix it!
LOL
Sue
I have posted this as a bug over on the beta testers page.Originally Posted by ceo1944
Cheers
Pat
"Some people might say that freedom is being alone in the bush with the only sounds being the murmurs from the birds ... but I believe freedom is at 5000 feet with no other sound than the engine roaring."- William Hutchison, a young man taken from us far too young (16).
Advance the throttles a bit and they will start/continue to run. It is different now. Idle causes engine shut-down.
Yes, but you'll need to modify the aircraft.cfg. In the [contact_points] section, modify point.0 and change the number 180 to 72. Or replace the line with this one:
point.0= 1, -34.550, 0.000, -2.940, 1200, 0, 0.600, 72.000, 0.420, 1.950, 0.700, 7.000, 7.000, 0, 165.1, 165.1 // 72=180 for free castoring
Dutch
I tried that too, I'm used to having to start the C-47 with throttles cracked, in fact this C-46 is one of the few I have that starts with throttles at idle.
Nothing, absolutely nothing I tried would get the engines to start. I tried selectively removing all the changes from the aircraft.cfg one at a time, and ended up with the old .air file and just a few lines from the old aircraft.cfg, and it works fine now.
I feel it's just a bit under powered out of the box at this point and adjusted the piston ratio a bit so that I could climb at the recommended speed of 105 knots and cruise at the expected speed of 150 knots with a 50% load. As distributed, I couldn't get it much above 120 with a 50% load. Also the CHT is off, like in most simulated pistons, and I adjusted the CHT record in the .air file to give more realistic temps (oil temps are fine, which is unusual, most sims get that wrong too.) I'll be happy to share these small easy changes with anyone who cares that much about it.
I enjoy flying the airplane. It's a nice simulation, and I appreciate the fixes in both SPs. Now I can read the glideslope/VOR in daylight, and the beacon switch is correctly labelled now
Dutch
Thank you very much Dutch. Now I can start to get somewhere.
Welll, I'm a bit torn over the new fde, or rather the difference between the fde's. You see, I consitantly fly out of Kunming, which was an eastern terminus for the hump route. It's altitude is 6300 feet. Now, the original fde could barely get the plane off the ground there due to the barometric pressure experienced at those altitudes, and high hot chinese weather.. Obviously, flying the hump required that planes be able to take off and land, but the original fde, didnt provide for that at that airport, and therefore airports throughout tibet and pakistan of which some are over ten thousand foot in altitude.
This new fde fixes that, but does it go too far?? Takeoffs are easy. Speed is a dream; perhaps too much of a dream. It seems to me that in acquiring functionality, its lost some of its reality.
In all my years of crunching numbers, balancing operational components making certain that each part of the flight model played nicely with each other part.
I learned something..
I learned that although reality was the goal, that it couldnt always be achieved with real data.
Because fsx is very set in the way it deals with everything, you have to work within those constraints that it sets. Whereas in the real world you can simply add more power to overcome an obstacle ( numerically of course ) in fsx you sometimes have to fudge things a bit. In this case I believe adding more power appears to have been a mistake, when what was needed was more lift. The plane now has too much power to match reality, and becomes rather unstable in turbulent skies.. More lift and weight could provide the plane with whats needed to match reality while remaining stable in turbulent conditions.
I do hope ive made some sense. Things arent always so clear to me any more..
Pam
Dutch please do share your changes as i trust your work after the payware you have worked on and seeing the end resultI tried that too, I'm used to having to start the C-47 with throttles cracked, in fact this C-46 is one of the few I have that starts with throttles at idle.
Nothing, absolutely nothing I tried would get the engines to start. I tried selectively removing all the changes from the aircraft.cfg one at a time, and ended up with the old .air file and just a few lines from the old aircraft.cfg, and it works fine now.
I feel it's just a bit under powered out of the box at this point and adjusted the piston ratio a bit so that I could climb at the recommended speed of 105 knots and cruise at the expected speed of 150 knots with a 50% load. As distributed, I couldn't get it much above 120 with a 50% load. Also the CHT is off, like in most simulated pistons, and I adjusted the CHT record in the .air file to give more realistic temps (oil temps are fine, which is unusual, most sims get that wrong too.) I'll be happy to share these small easy changes with anyone who cares that much about it.
I enjoy flying the airplane. It's a nice simulation, and I appreciate the fixes in both SPs. Now I can read the glideslope/VOR in daylight, and the beacon switch is correctly labelled now
Dutch
It only needed a little lift, reduction of beta max and a minor increase in prop thrust..
maybe, but ive worked with dutch in the past on a payware package and know his talents and im interested to see what he has come with with
Hi Jeansy,
I really don't have much time to do anything extensive, I'm too busy with payware projects. But I do like this C-46 and it's a fine Air America aircraft. I have an Air America career I pursue in FSCaptain, mostly as a test bed for the new missions system, but I'm a sucker for any airplane that matches a historical Air America plane. So far I have the PC-6 from Tim, C-45 from Milton, C-46 (this), C-47 (Jahn), T-28 (Ant's) and of course the UH-1 (Milviz). I would *love* a C-123, H-34, or C-7 but haven't found a high enough quality one of any of these. I'm spoiled by the ever higher quality of add-ons, freeware and pay, we have nowadays.
Warchild is right in that the main problem is it's a little under powered. It can't get to any of its typical speeds with a typical load. After tinkering a bit I found a boost of the piston power scalar to 1.27 gets the numbers about right between sea level and 6000 feet. With FSX/P3D you can't get everything right at every altitude, you have to pick and choose. I try to get the numbers right for the airplane's typical environment, which for the C-46 is NOT way up high.
I find like most pistons the CHT is too low. No matter what you do you can't get the cylinder temps anywhere near red line. Not true in reality, of course. To fix this you have to edit the air file. Record 541 is Engine CHT. Make the tuning constant 1.29, the cooling constant 0.75, max temp 960, and rate of change 0.015 - this will get it in a more realistic range. Abusing the engines can now get you over red line. Of course, there will be no consequences unless you have some external code like RealEngine to monitor these things. I have some XML I moved over from the old DC-3C I did long ago and I've put that into just about every piston I have, and changed the red line numbers.
All this is really just easy tinkering to make things a little more realistic.
Dutch
Its all good dutch i have custom fde i made up, im happy with what i have, i just wanted to see what you have done
Im happy now i can climb to 8000ft without stalling even when my climb rate is 100 fpm unlike the fde it was shipped with
Thanks for the tip to increase .... piston power scalar to 1.27 .
It's now got a respectable take off and climb performance.
What figures have you for the roll stability? Mine just goes back wings level if I release the roll input.
Thanks.
Pete.
Hi Timmy. Yes there is.. Open the aircraft.cfg file and scroll down to where it says [Contact Points]..
Checheck line one and make zure its not the same s line two, then move over across the line to entry 7. In a castoring setup that muber will usually be 180, showing that wheel rotate 180 degrees. Change that to something lower. I prefer 34 myself but other people use other angles.. save and have fun,,,
Warchild and Jeansy - are these changes for the SP2 version of the C-46 or the first one? I have had time to have a look at this one again as I have been fiddling with another product the HS748.
Members who have read this thread: 1
Posting Permissions
FSX
Bookmarks