My Learning to fly the UIVER DC-2 thread.

[mrcapitalism]

So I've had the 'UIVER' DC-2 for over a year now... thanks to the suggestion from this website . I've finally decided to put some time into learning how to properly operate it. My intention of this thread is to share some observations and promote discussion on this aircraft and other's like it.

After reading the manual, and some experimental pattern work, it's first duty was to fly the infamous AM-21 route from Ernie Gann's Fate Is The Hunter. As I flew it, the route was KEWR-KAVP-KSYR-KROC-KBUF-KERI-KCLE.
I didn't touch it for months until now.. my latest adventure is to fly a CNAC (China National Aviation Corporation) 'bus stop' route from Shanghai to Beijing. Seems these aircraft were popular on multi-stop routes. But my skills have lapsed, and I'm having trouble controlling it's speed and engines, I thought I should seek advice from others. Back to the traffic pattern I go...

The main issues I'm having regard approach RPM, minimum power, and flap management. Flying notes come in the form of a tutorial from the manual, handling notes from what appear to be a scanned real aircraft manual, a checklist, and notes from a modern day DC-2 pilot of the subject aircraft. They often times don't agree, and other times provide no guidance.

Approach RPM: The real life documentation makes no mention of the RPM setting on approach. The handling notes command maximum RPM (2350) on final, and so does the RL pilot's notes. But the checklist commands 2100 RPM. 2350 RPM is TOGA, and TOGA is limited to 2 minutes. METO is 2300, Climb is 2000, and cruise is 1850. I assume 1850 is what I would have when joining the downwind. I'm not so sure about commanding TOGA RPM (even without making that amount of power) just due to fears of the vibration/rotating stress on engine parts. The only place 2100 RPM is ever mentioned is on the checklist page.. but I can see it being a moderate setting ready to "spool the engines up to TOGA." Considering the age of this aircraft.. more defined settings in later propliners may have instead been allowed to be pilot preference. I don't know what RPM I should be setting, and I fear 2350 is too much.

Curious things are going on with the propellers of this aircraft. They have a very wide range of available blade pitch, and it gives them a great deal of control over aircraft performance. Commanding 2350, with idle power the governor will still have RPM control all the way down to VREF, only loosing control as the aircraft nears stall! I compare this to some flight's I've made in the B247(FSAviator FD), in which even following the handling notes, I will loose control of the RPM while on the downwind. At that point the checklist commands full RPM but it doesn't matter as the aircraft in effect behaves like it has fixed pitch propellers for the circuit and landing. Not so in the DC-2. You always have full RPM control.

Another interesting observation, these propellers have a HUGE impact on performance. At 1850 RPM the DC-2 is very hard to slow down/descend, but the propellers become gigantic air brakes when advanced to even 2100.. more so than the gear. The opposite is true on takeoff, reducing RPM gives a massive increase in thrust efficiency and contributes greatly to acceleration for the initial climb! With the gear down and 1850 "square" the airplane will slow to 100 KIAS, but not much less than that.. and will barely descend at 100 KIAS, even with the gear down. Starting from 1500ft AGL if I keep this RPM I find I turn base at about 1400-1300ft and 100 KIAS. That doesn't feel like enough. My early approaches had me turning final excessively high, and with still too much speed. I first tried to compensate this by starting a very early descent (500ft AGL on downwind!) but these approaches were dangerously flat... this problem sent me back into the pattern all the way from China for more practice.

So at this point I now set 2000-2100 RPM on downwind. At 100 KIAS with gear down I find this gives me enough windmilling drag to manage a 500 FPM descend if I allow MAP to reduce to 15"-17".. under-square but will discuss that later. I still have to slow, VFE is 87 KIAS and VREF is 60-65 KIAS (modern pilot's notes.. checklist 70, scanned manual makes no reference except VMCA=65 KIAS) That's a lot of slowing down while going down! Lets talk about my less than ideal solution for doing this.

Minimum MAP: Nothing anywhere gives any reference to minimum MAP. My "American indoctrination" gives me an uneasy feeling about this.. and yet I find it's impossible to fly by keeping MAP >= RPM/100. It just doesn't slow down or go down. The only exception is the massive drag and nose down of full flaps, but I have to slow to below 87 KIAS to deploy them (and realistically <70 KIAS to avoid a huge propose). Even at VREF with Full flaps and 2100 RPM I need less than 19" MAP to stay on a 3º glideslope!. It's not possible, and leads me to believe that this doctrine didn't apply to the DC-2. So in the case of this airplane, should I just ignore any minimum MAP limit? Was it safe to idle these single speed blower engines if I needed to (still respecting shock cooling limits)? Even with TOGA RPM?

Flap management: Real life manual states "Flaps must not be extended until your indicated airspeed has dropped to 87 K or less." VFE is stated as 87 KIAS, but the "system description" of the flaps notes "note - do not extend the flaps COMPLETELY above 87 KIAS (hydraulic system may take damage)." This sim will fail the hydraulics if you exceed VFE, but the first stage of flap is excepted from that restraint (via my flight testing). The real life pilot instructs to set first flap setting at 100 KIAS when making the base turn, but perhaps he means to wait until after slowing below VFE to 80 KIAS the target speed for base? There's no mention. This was more a problem when I was still coming in fast at 1850 RPM, but now that I'm pushing the props up the added drag is really helping with my flap management.

Full flaps needs it's own discussion, as it has A LOT of lift and drag! Wow! In my "steeper, higher RPM" pattern procedure I need about 15" MAP to keep a descent going around 500 FPM. Even if I slow down to 70 KIAS before calling for final flaps there's a very large nose up effect combined with a speed reduction as lift and drag both massively increase. Suddenly the approach shifts from a nearly flat pitch to a couple degrees nose down just to stay on the glideslope. Now I finally need close to "square" MAP. This makes the round out and touchdown VERY tricky... just as Gann described it all those years ago. Adding full flaps comes with a substantial forward control column deflection, and a good turn of the trim handle.. it then settles nicely into a stable approach at 65 KIAS, 2100 RPM, 17-19" MAP. The DC-2 likes to land firm.. and get that tailwheel down before the horizontal stabilizer stops flying and it comes crashing down!

That's all I have for discussion on this aircraft at this time.. hope you enjoyed reading! I would appreciate any input you guys might have.

What should I be setting for approach RPM? Final RPM? Can I really go all the way up to TOGA? Can I just choose at the moment what RPM gives me the speed/descent I need, and use it as a tool to control my approach (variable RPM setting)?
How low can I go with the MAP?
Can I put out that first stage of flap fast? Or do I need to wait until VFE, because it applies to all flap settings?

Thanks everyone. I'll post more as I practice more.

[Tom/CalClassic]

The online UIVER FSX manual says:

Descend:For descend reduce throttle. First to 20” 1850 RPM.

Down wind leg:First slow down in airspeed during level flight.

Mid down-wind: gear down (2 green lights). Adjust speed with throttle to maintain a speed of 100 knots, due to increased drag by the gear.

End of down-wind speed 100 knots. Set flap 15°.

Base leg:Set flaps 25°. On base leg, reduce airspeed to 80 knots, and keep reducing throttle to have a descend rate of 500 fpm.

On Final:Props to High RPM. Reduce airspeed to 65 knots (safety margin). Full Flaps

Final Check: Fuel booster pumps on. Full flaps. Landing clearance.

Threshold speed 65 - 60 knots

Hope this helps,

[connieguy]

I find your post an exceptionally interesting one and hope that what follows might be of some assistance. I don't have the DC-2 but have occasionally thought of buying it. I well recall Gann's comments about the difficulty of landing this aircraft and also seem to recall that he was left to work this out for himself without any assistance from the senior pilot he was flying with. I have, incidentally, never come across any manual for an FS aircraft which describes these things adequately, which is rather the Gann experience. However, there are certain settings you must know and once you know them things ought to work. What follows is my method for finding them.

Take the aircraft to an adequate height and reduce the fuel to what would be about landing amount. If there is an autopilot switch it on long enough for the aircraft to become settled in cruise and note the trim setting. This is easy in the Constellations I fly because there is a digital trim readout in the VC. Where there is nothing of this type I have always installed a digital trim gauge. Two buttons on my joystick give small increases or decreases, but in the Constellations it is as easy to adjust trim by clicking on the trimwheel in the vc, and this also allows one to adjust trim more rapidly if necessary, which it will be.

Once set, switch off the autopilot and reduce manifold pressure and rpm to get an adequate descent rate. Keep playing around with the settings until you are satisfied. There is no hurry, because you are not going to be landing anywhere anytime soon. If there is no other way of doing it trim the nose down slightly. Once you are satisfied write down the settings you have used so that you can refer to them in future. Then prepare to go to Flaps 1 by trimming the nose up in a number of gentle stages, probably keeping the descent rate at about zero if you can. As the nose rises the airspeed will drop, eventually to the point where you can lower the flaps without damage. Write down the correct trim level so that you know it in future and then move the flap lever. As you do so the nose will rear into the air. I have no idea whether the following method works in real life but it does in FS - at the same time as lowering the flaps quickly trim the nose down by several points and eliminate the rearing effect. Again you may have to experiment but once you know the right setting write it down. As the aircraft settles it will then begin to descend more steeply than you want, so increase the trim again perhaps by half of the amount you have just decreased it and also (possibly) increase both manifold pressure and rpm. What I want to know at this point is the settings at which the aircraft will fly level at Flaps 1. Alter trim, rpm and mp until you are satisfied and then write the settings down. On the Constellations if the mp is set at about 25 it is possible to control descent by varying rpm alone, and this means that flying the aircraft becomes very precise, as it should be.

Eventually you will lower the gear and this may require increases in mp, rpm and trim, although in the Constellations the effect of lowering the gear is not massive. Once it is down find the settings at which the aircraft will fly level and write them down. Descent may well be still adjustable simply by varying rpm. Going to Flaps 2 has little effect in terms of the nose rising but as the aircraft settles you will probably need to increase rpm amd mp as well as trim. If you aren't already there, fuel should now be at Auto-Rich and the cowl flaps well open, although I know that on the DC-2 there are no cowl flaps. Once at Flaps 2 find the settings at which the aircraft flies level and write them down. In the Constellations that trim is landing trim - no further adjustment is necessary on going to Flaps 100, but variations in descent rate now tend to require alterations to both mp and rpm.

Once you have all this information go and find a runway to land on. Hope this helps.