Charles,

You probably are right on the math.
Anyway, If I pull the power back to about 23in MP and 2100 RPM I can get the plane to run LOP. Based on looking at the charts which stop at 50% power, I think I am running about 40% power. This normally gives me 135-140 KIAS. Fuel Flow was around 13/14 GPH per engine but I use 18GPH per engine for flight planning


Tim

If you're running 14gph LOP and have typical 7.5:1 compression ratio, that would be about 55% power. The (I presume) ROP perf charts may be hard to extrapolate to LOP but 13.7 times FF will give you HP.

Compression is 7.3. Even lower

Tim

I hate to show my smug satisfaction at owning the A* with the "baby engines", but well, I just have to.

When I'm flying below 8,000 or so, where I don't need/want pressurization, I will pull back to 2200/20". At that setting, I'm still truing 145-150 knots and burning 10 per side ROP. I guess with LOP, 9/side would be a gimme. The problem with that at altitude is that I need at least 22" to keep my pressurization. On one of my early pressurization flights, I was cruising at 22" and when I started my descent, pulled the throttles back. I had a headache for two days.

My performance seems to mirror the speed and fuel burns shown on in my POH which are revised since I have the Machen intercoolers. The "book" says that I can get 240 knots true at altitude and 75% with a 36 gph fuel burn. I suppose I'll have to try it sometime just so I can gloat some more??????

Jgreen

I think says it all.

Tim

Hmmmm....me thinks his is faster than yours.

I think says it all.

Tim

Marcus,

Notice I said "early" pressurization flights. Habit my friend, just pure habit.

I will admit that I have still not adjusted to how difficult it is to get rid of excess energy with the Aerostar. The Bravo was like that but had speed brakes. For now, I'm trying to err on the side of caution, making sure that on any approach, instrument or VFR, that I am at altitude and speed at least three miles out; say from the FAF. One positive is that I can can put down 20 degrees of flaps at 174 knots, I'm learning to quit thinking "efficiency" and do that as a matter of course no later than the IAF.

As to the comment that I'm faster than Tim, no way. That gas hog 700 will scream when he wants it to. Tim is still young and in a hurry to get somewhere so he can wait impatiently. I figure that whatever I'm going to will still be there when I arrive.

Jgreen

John,

If VFR, a cool trick to slow down from my Cirrus days. Pitch up in a side slip. Dumps speed pretty fast. Note: I never do this with flaps out since it places a significant side load on hinges.

As for the rest.
Yah, I am impatient. I am trying to work a long shot deal so I can go turbine and go faster!

Tim

Hi Glenn and John...glad you are enjoying the economy the TN Lycoming engines provides but wanted to share that running the less fuel efficient 350 hp low compression engines) can produce similar numbers to the TN Aerostar 601P. Being a LOP guy at heart (flew Barons and Bonanzas LOP for 2,000+ hours), as Tim stated, to run my engines LOP I have to be at a low power settings not to exceed TIT limits. That said, at low power/long range settings I have been surprised at the fuel efficiency of the the low compression engines over the 250 hours I have flow the Superstar 700. Here are my low power settings and fuel flows (I have the winglets installed which help the most at these slow speeds and high induced drag profiles):

LOP settings at FL210:

29"/2,100 207 KTAS 26.8 gph

ROP settings at FL210

25"/2,100 209 KTAS 27.7 gph (2 knots faster and less than a gallon difference from LOP
@ 29"/2,100 so hardly worth the effort)


Flying a slow approach @ 120 KIAS allow a fuel flow of just 20 gph. An economy climb can be flown at 48 gph at 140 KIAS providing a 1,000 fpm so about .81 gph per 1,000'. And Marcus, yes these planes are made to fly fast so when I want to spend another $6-8 for every minute I arrive earlier than low power settings provide, I push up the Throttle and mixtures and enjoy 260 KTAS +/-. Most of the time I fly at long range power settings like John, I am not in that big of a hurry to get to my destination...but I rationalize it is nice to have a lot of reserve power for takeoff and for carrying heavy loads (at the price of a lot more fuel burn when I use these benefits). So the 350 hp Aerostar can be flow in a fuel efficient manner like flying a normally aspirated Baron LOP at similar speeds (or faster at higher altitudes with the benefit of pressurization) or just about as fast as a King Air 200 at FL250 without the dependability of turbine engines of course but also without the costs of the associated ABCD phase inspections, gear inspections and other calendar inspections...albeit with a much smaller cabin. Don't want to spend the money on a King Air (would be overkill for my mission) but it is fun to be asked to slow down for the regional jet on final when I want to let all the horses play as I head downhill.

Rationalization is my best skill set!

Tom

Isn't it fun to rationalize what we love to do!

Interesting. Previous to the Aerostar, pretty much all of my time was also in a Mooney. However it did not have speed brakes and a had 120mph gear extension speed (1965 M20E). I find energy management MUCH easier in the Aerostar. I try to error sightly on the faster side...when I am ready for them, full flaps is like putting the brakes on.

Glenn

Me too
...but if the Aerostar was the last plane I own/fly I think I would be happy.

Glenn

I feed both an Aerostar and a Bell-47. I am SO FAR beyond rationalization, that I have no clue what you are talking about

Glenn

Me too
...but if the Aerostar was the last plane I own/fly I think I would be happy.

Glenn