Spark/Ignition Analysers, Round Engines?

[meleagertoo]

I seem to recall some of the older farts I used to work with at BAF maundering on abour their old Carvairs (aka DC6s) and the extraordinarily complex engine management that was required in those days. One of the features was apparently (or am I dreaming?) a panel that analysed the ignition systems of the four engines so as to troubleshoot them if required.

Any of my former highly esteemed colleagues out there or any other radial operators who recall this, or indeed any of the fine detail of engine handling of these evidently somewhat delicate systems?
And can add explanations in as much detail as you wish?

Do I recall tales of power, flap, gear and and prop settings used far out on the approach so as to avoid any changes in throttle settings at all until landing as throttle/power setting changes upset the engines? Or was I being fed a tale?

Explaations on technique would be fascinating.

[Self loading bear]

Double thread posted?

[sycamore]

All very true Mel; I think the analyser was an oscilloscope which could be cycled through each engine in turn and then each plug on each magneto.Depending what the `picture` showed ,the `gingerbeer` could determine what condition the ignition/mixture strength was..An `ECG` for the engines in simple terms..
With respect to the selection /reduction of `power` on big radials ,for descent,the throttle(s) should not usually be reduced to the extent that manifold pressure is low enough that the propeller is being `driven by the airspeed` and prop RPM in the governing range...ie approx 15"MAP ,and 1500 RPM..A further reduction in MAP will cause the prop to be `unloaded` by airspeed an this can cause `big-end problems` with oil flow to the bearings....as the oil ways are designed to cater for the` Prop pulling the aircraft`,and not driven...
Same was true on the C-130, if one was aggressive pulling the throttles back in a descent ,one could get a Negative `Torque` indication ,but it would trigger the NTS to `coarsen ` the props...
All good reasons to set the aircraft up nicely stabilised,so you only need to keep reducing power down to touchdown.....

[megan]

The following are from a Lockheed 1049 (Constellation) manual, engine R-3350 turbo compound, also fitted with spark advance/retard switch.

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/704x844/lf_315ffc158a71e4640cf3f58060b06e27315c1704_fa30ac6603707bed e363be5aa59fd587102fd6a1.png
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/688x836/le_acf14c4c82e3eefde8c77d626239cab1ee3a60a5_28b72522899e15f6 87b160ab67391a49ca200929.png
https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/700x833/ld_6005d257231b2412a7bceb0263b3dd2249287904_52386b45fee9575f 544cca9eb61664cd3b4e2a42.png
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/682x827/lc_ddacaecb6923284f77aa273a4c792bfa2e7858fe_bb9cddc3c915a0ae 4ab8729cdfd02612c4e72262.png
https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/704x845/lb_6b8a882959fc1d15b0a43471b3368c4d695a1c9c_0018df179a936c79 c9fe1067be8dd53604609ec4.png
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/712x850/la_f5a19f8403b54f2ef993ec0a113ed3d55b422483_b2797dc95c5938ba 592a370d93e044820b94e217.png
https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/1103x1569/c_fc8c920eedf60f5dc7d5d94510c5f66f2dbac5d8_436b64671a403d063 5e7dc39fa1d9c2f5aa55cb2.png