Engine Out Performance

[Humphrey]

GBOWD (N337UK by end May) finally flew after a 2 year rebuild. Flight test was fine except for usual snags and a descent with the front engine only. What is the real world experience for performance versus book figures?
Its a F337G, new prop, for the CAA test flight we were 200lb under max at 4400lb, 3000 feet, 6C, rear fully feathered, rear cowl closed, gear and flaps up, extrapolation of book numbers indicates 265 feet per minute positive. The actual result was a 200 foot per minute descent.
Grateful for any real world advise. Surprising thing is that to put this aircraft on The US register doesnt require this sort of flight test, which also includes a VNE dive to ensure no boom flutter, or control handling problems!!!
Humphrey Penney

[Ernie Martin]

I don't have any measured first-hand performance, but have read a large number (like 3-6) of accounts over the years suggesting that the airplane does better than the book numbers. And, until now, don't recall reading any accounts of lesser performance. The better-than-book performance seemed surprising to me (I'm a mechanical engineer, MS Caltech) because you'd reckon that a) Cessna would have measured carefully and published realistic (not pessimistic) data, and b) over the years the aircraft has to degrade in performance (if nothing else, drag has to increase compared to new skins).

I hope others jump in here and tell us their experience.

Ernie

[rick bell]

lost a rear engine once, before clean up it was negative. after cleanup required near max power to roc at 200+. around 8k and 80% loaded(i think 6yrs back)

[kevin]

I have one instructor-induced actual engine failure in a '65 337 under my belt. The instructor turned the fuel off to the rear engine, unbeknownst to me, as we were on short final to a near sea-level runway on an 85 degree day. *We were light, a total of 600 lbs of passengers, and half tanks.* As I flared, he yelled "go around, go around". I initiated goaround, and as I advanced the throttles, the rear engine failed. I had to identify-verify-feather the rear, milk up the flaps from full to no flaps, all while maintaining altitude. I left the gear down, not wanting to have the gear door drag. After I got the flaps to 20 degrees, we started climbing. It took about 4000' of the 5500' runway to do this. When I got the flaps up completely, we climbed at about 250 - 300 fpm (hard to read a VSI really accurately). The climb performance was quite sensitive to blue line speed, you have to maintain it exactly, or you lose a lot of climb performance. And getting slow exacts a big penalty in climb until you get the speed back up.

After I changed my underwear later, I asked my instructor why the HELL he did that. He told me he would never do it again, but he thought every pilot should see what an engine failure at the worst moment is like at least once. I think it was an unsafe thing to do, and at the same time I am happy to have had the experience (I would be less happy if I had feathered the wrong engine for example).

Somewhere in the messages on this site is the result of a test I did on a '73 P337 to see if single engine performance was as advertised at altitude. Although I did not feather the rear prop at that time, I found lots of climb performance left at 12000' with feather simulated on the rear engine, as I recall.

So, if you are not getting near book climb performance out of your airplane, there is something wrong, in my opinion.

Ernie, I think where these "better than book" ideas come from is that most folks do their testing at less than full gross, and forget that that will improve performance. I, like you, seriously doubt the airplane will do better than book. I think it is like takeoff performance. Your mileage will vary, and it will always be at least a little worse...

Kevin

[Dave Underwood]

On my FT337GP and another F model at EGBE, we have both got close to the book figures on single engine. Note that Zero thrust rpm on the rear engine is 2100 as I recall and 1900 on the front.

Go the N reg route and get away from that sort of stuff would be my only recommendation. There are more planes doing it at EGBE all the time.

Regards - Dave

[Dale Campbell]

I had a instructor do a simmular thing to me, but not as bad.
It was a 85 degree day with 3/4 full tanks. I had my son-in-law in back seat, so near gross weight. On take off after wheels up at 300 feet AGL. He pulled my front engine to idle. I dropped the nose to maintain 90 knots. It would not climb at all at that point. I made a slow turn to left to go down wind. After I turned I gained about 90 feet before turning base to land. Part of my climb problem, was the idle engine was creating drag. I know how that feels and I could have brought the front engine back if I needed it. It was a good experiance. That proved to me, a 337 is the best aircraft to have a engine out problem.

[sunnysky]

Used to own G BOWD in the late 80s. We bought it from a guy who had an engine seize(rear) on the approach into Newcastle. UK> Bought a new motor from T.W. Smith in the States and it cost as much as we paid for the new motor to de snag it in the UK. Eventually got it "right" and sold the plane on. Seem to remember doing a flight test way back then for the issue of a CofA. Climb performance would have been ok, and we would have used the front engine for that single engine climb test. Is the rear prop fully feathering as even a slow windmill can cancel any climb. Good luck with BOWD. We did, completing many long trips to Spain, Portugal etc.
Sunnysky

[Richard]

What kind of speed were you indicating? I've noticed that I can't get any positive climb until I slow to 110 mph indicated. (rear engine out). I can maintain altitude at 120 mph indicated. The only time I saw 250+ on the front only was at 95 mph indicated.

[kevin]

Best single-engine rate of climb for your airplane is 99 mph, should be marked as blue line on your airspeed indicator. Best angle is 89 mph.

Kevin

[rick bell]

for the hell of it i cut both engines on the downwind at at end of the runway. not a good idea (bonehead award). engines not feathered took a 60 bank and maybe 30-40 dive and just bearly made the threashold. a rock has a better glide ratio. don't think i'll do it agan, owever i now know waht to expect. do not rembemer the speeds, just knew i needed to dive and bank as hard as i could. almost looked like the sot landing video .

[SkyKing]

Rick,

Assume you had the flaps tucked and just the gear down when you chopped both engines... you would have had MUCH better results with the props feathered.

If you look at the glide chart in the Emergency section of the POH, you'll discover that if those parameters are followed, the P337 does way better than a T210!

SkyKing

[OSCARDEUCE]

At about 3900 lbs, stores on thew wings my O2-A is lucky to maintain 2000 ft 85-90 kts)at 85F. Not near what some of you guys are getting. Engine out is a little tricky.