New Engine, Flight Training, etc

[AndyFromCB]

So I decided to go out to MN and get some training with Bruce Jeager. Spent entire day last Friday and 4 hours on Sunday. Worth the price. 12 hours of training set me back $525 plus fuel. A fully loaded M20M will take off and fly with flaps fully down, gear down and speed brakes out and still climb at around 400fpm. Good to know.

As to the new engine, can't get #1 to stay cool, no matter what I do. 420 in climb, close to 400 in cruise at 30/2400. Seems to run EGT 75 higher than the rest. Any thoughts?

As per Bruce, if I want my exhaust to last, I need to keep my TIT around 1550, not 1650 and don't even think about 1750. Any thoughts? Keep the RPM up as well, so none of the 2200rpm power settings unless it's 24inch MP so as the turbo doesn't work as hard. I agree.

Did some 4 way runs this morning at 12,000, DA closer to 14,000, here is what I found, 25 hours on the engine so far:

30/2400, pumping 20gph to keep TIT at 1550, 190knots

28/2400, pumping 19gph to keep TIT at 1550, 184knots

26/2400, pumping 16.5 to keep TIT at 1550, 178knots

24/2400, pumping 15.5 to keep TIT at 1550, 167knots

24/2200, pumping 13 to keep TIT at 1550, 161knots

At 26/2400, engine runs cool, TIT is cool, I'm seeing close 180knots, I'm a pretty happy camper. I know my fuel burn would go down considerably if I run peak TIT, but that exhaust transition is a $7K piece.

So, from other Bravo drivers, where do you run your TIT? How many hours, what has been your experience.

[Steve Dawson]

I'm interested in buying a Bravo in the near future so I'd like to find out also.

[carqwik]

In my Bravo, the #6 cylinder runs hotter than the rest...similar to yours. Cannot figure out why...just is so. Best thing is to put more gas through the engine and leave cowl flaps in trail even during cruise.

Don't know about 1550 being ideal...have been told and read from experts that TIT above 1650 should be limited to 60 seconds or less and only for the purposes of leaning to find peak. At 30/2400, I am usually around 1580-1600 on TIT in cruise.

Btw, engine will run cooler in the winter....

[gjkirsch]

I typically run 30/2400 with a fuel burn of between 19 and 20 GPH, keep the TIT below 1600. My cylinder temps average 350 and oil at 190. I have no problems with oil or cylinder temps in climb. I lean to 1500 TIT in climb and in cool temps set the cowl to the half position. This is my second Bravo and both ran around the same temps and fuel burns. Your temps appear to be a little high.

[Awful_Charlie]

I can't afford to cruise with fuel burns like that!!!

I normally use 30"/2200 and lean until the last cylinder peaks - for me this is normally #5. Normal cruise is #1 with the hottest CHT, and I can keep temps down without resorting to the cowl flaps in the cruise. I only see high TITs when using 32" or more of MP, at 30" or below I can't get over 1500-1600 or so. Sample from last two times out:

FL170 , about 0degC

19.8 down to 15.5USG/hr - 139KIAS

15.1 USH/hr - 138KIAS

14.6 USG/hr - 138KIAS (this is the book FF figure)

13.7USG/hr - 136KIAS

13.3USG/hr - 135KIAS

12.7USG/hr - 132KIAS (this is about 177KTAS)

FL160, also 0decC, +/- 1

21.3 down to 16.4 USG/hr - 139KIAS, 182KTAS

14.0USG/hr - 135KIAS/178KTAS

13.4USG/hr - 130KIAS/172KTAS

12.3USG/hr - 125KIAS/166KTAS

The JPI peak finder found 13.9 for ROP and 13.1 for LOP

[AndyFromCB]

It used to run cooler than that. I was hoping to see a significant drop in temperatures as the engine breaks in, but that hasn't been the case, a small drop after first 5 hours and that's about it. It also doesn't help that all my flights have been in 95+ F surface temperature range. On my 12,000 foot 4 way runs it was still close to 20C at that altitude. I've been keeping my cowl flaps about 1/2 open in cruise and that keeps everything below 400F at a cost of about 2 to 3 knots of airspeed.

Now that it's finally cooler, I'm going to try to go up tomorrow morning and see what's up. I seem to have no problems what so ever peaking at over 1650 at most power settings over 26inches and 2400rpm. I don't like the 2200 setting. At 2400, my engine is turbine smooth after prop balancing and at 2200, the vibration increases. Still much less than my Arrow or Super D (RIP) at any setting, but at 2400, there is no vibration in the cabin what so ever.

Andy

[Parker_Woodruff]

You should do a GAMI lean test once the engine is broken in to find out if you have a significantly lean cylinder on #1. You may also have a clogged injector.

Even if you can't get the plane to fly LOP, you'd still probably save some money if your engine gets a good GAMI spread.