Single-engine Endurance and Performance

[Cole5Oh5]

This is supposed to be a valid test.

Do it over the water. See what happens. It's amazing what a little reality dose does to your pucker factor. And the validity of your test.

[tropical]

Just a side note on "zero thrust" settings. Even if you have set the book "zero thrust setting" you are still producing a small amount of thrust.

The airplane will behave differently. Try it with "zero thrust" then go back and feather the engine. It's an eye opener.

[Jim Rainer]

I vote YES:

Normally aspirited '76G; FE prop feathered ;4200 +/- weight; summer; 6,500;TAS 115K +/-; 24/24; actual flight from GPT to AWM after losing front engine SE of GWO - continued to AWM. No sweat; opened RE cowl flap 1/2 but don't think it was necessary.

Took a mountain flying course with a United instructor who wrote the book on mountain flying over Leadville, CO; summer; again about 4200lbs at about 11,000 and he asked if it would sink quickly or slowly. Told him I did not kow so he simulated zero thrust and to both our surprises, it mantained altitutde!! We didn't do this long enough for a true test but we both thought it would start down at least 500' per min.

[jchronic]

I vote 'Yes.' It's true that the POH numbers were generated on the basis of a new, clean airplane flown by a factory test pilot (and such computer data as was available in the 1960s). But from what I remember when I checked the performance numbers when I started the marine surveys a few years ago, I was comfortable I could get back to dry land on one engine, even with an airplane at near max gross (4200#) - bearing in mind that I'm talking about already being at 700' when the engine craps out.

Even if your airplane is so out of rig or dented that you couldn't maintain, say, 5000,' at max continuous (25/25) the sink rate should be minimal, down to a point where you'd be in ground effect. That would cover a lot of ground (or water).

Regarding the engines, I'd start at the top of the green arc and see what it gave me. If the airplane wasn't holding altitude, I'd let it sink until I wasn't comfortable going any lower and then use it all. A good reason to baby the engines under normal circumstances.

All of this is analogous to the 'driftdown' procedure we used in the airlines on the heavy jets.

Finally, unless you're alone, don't forget about throwing stuff out the cargo door (women and children first?)

Ahab

[WebMaster]

Have you done it yet, Ernie??

Inquiring minds want to know.

[Ernie Martin]

Hoping to do it this weekend.

Ernie

[billsheila]

I did this when I went flying in N2131X with the Terrafugia boys who wanted to learn some things about Skymasters and "blown elevators" (as their test pilot referred to it) and as they were toiling with getting the flying car going. In that case we were pretty close to your question, except for the temps, which were right around standard.

Max gross, front engine set for zero thrust. It would fly along all day long at 25/25 on the rear engine at 5000. I have only done a more legit test once when I mistakenly ran the rear engine out of gas. I didn't mess around with gathering data that day, as I was IFR and got it going again in about 20 seconds!

Bill