Hi Tim...sure is a fun airplane to fly when you can perform descents like the one you described in addition to the Aerostar's climb, speed, handling and even low power/long range "frugal" abilities. Enjoyed a couple of precision approaches on my last trip (ILS and a GPS WAAS) to about 600' using the Flight Director but hand flying...man this plane handles precisely and honestly!

Tom

Adam,

I would suggest you contact Jim Christy at AAC. He is on BT if you want to send a PM. Or send me a PM and I will give you his contact info.
It would be a short flight from CA to the AAC factory and Jim can show you around so you know what is available in terms of support and also give you a demo flight.
While there you can drool over the Aerostar with the twin jet engines mounted under the wings.

Tim

Tim,

What is the difference between the MM and U2A engines as far as operating altitude? and why would one be made with turbos and another without and the same HP?

Larry,

There are three common engines you will see on Aerostars (there are other variants, but these are the most common that I have seen).
TIO-540-U2A
IO-540-S1A5
or IO-540-AA1A5

When you see MM after the engine model e.g. IO-540-S1A5 (MM) that is a Lycoming engine which has been modified by Machen to increase power or detonation margin. They can make the changes through a series of upgrades, including turbos, intercoolers and other tricks raise the HP from a stock 290 to 350. Basically, any 601P, 602P, 700 are turbo charged, the question is how much.

From what I followed, and I am getting in WAY over my head here, the changes depending on the engine may involve the following:
-- Mags (between Bendix/Slick and pressurized)
-- Adding intercooler
-- Changing max upper deck pressure
-- Fuel controller
-- Changing turbos

In terms of critical altitude, I think the U2A engines are supposed to carry full power a few K higher than the others. From a practical standpoint, no performance difference between the engines. The U2A has the "wide deck" changes which are supposed to make the engine more robust than the "narrow deck". And at this point I really am talking out of my a**

Tim

I miss having a reclining pilot's seat in the Aerostar, but other than that, I have no real complaints so far. My wife loves the extra foot or so of width in the back of the cabin, vs. the A36/B58 interiors.

Fueling the airplane requires quite a bit more attention than with a Baron. My Aerostar has the fuselage tank overfill kit installed, and there's no way I could leave the airplane at the FBO with fueling instructions.

Oh yeah, I have to share a hangar with someone else. The Aerostar won't fit in any t-hangars available around here.

If we cross paths...I will! But I have a slower (and more efficient) 601P.

Glenn

Larry,

There are three common engines you will see on Aerostars (there are other variants, but these are the most common that I have seen).
TIO-540-U2A
IO-540-S1A5
or IO-540-AA1A5

When you see MM after the engine model e.g. IO-540-S1A5 (MM) that is a Lycoming engine which has been modified by Machen to increase power or detonation margin. They can make the changes through a series of upgrades, including turbos, intercoolers and other tricks raise the HP from a stock 290 to 350. Basically, any 601P, 602P, 700 are turbo charged, the question is how much.

From what I followed, and I am getting in WAY over my head here, the changes depending on the engine may involve the following:
-- Mags (between Bendix/Slick and pressurized)
-- Adding intercooler
-- Changing max upper deck pressure
-- Fuel controller
-- Changing turbos

In terms of critical altitude, I think the U2A engines are supposed to carry full power a few K higher than the others. From a practical standpoint, no performance difference between the engines. The U2A has the "wide deck" changes which are supposed to make the engine more robust than the "narrow deck". And at this point I really am talking out of my a**

Tim

Nope. Because it may be listed as Option #247 installed.

Here is the current upgrade list:
http://www.aerostaraircraft.com/Install ... 202-13.pdf


Tim

Nope. Because it may be listed as Option #247 installed.

Here is the current upgrade list:
http://www.aerostaraircraft.com/Install ... 202-13.pdf


Tim

Larry,
Tim asked me to jump in here regarding engines. All of the turbocharged engines supplied by Lycoming for the original Aerostars were designed to be turbocharged but left the Lycoming plant without certain items like the exhaust system, turbochargers, waste gates, turbo actuators and controllers. The airframe manufacturer supplied those items, whether that was Ted Smith Aerostar or Piper.
The IO-540-S1A5 was a turbo- normalized 290 hp engines with 8.7 to1 compression rated at 29.5” map and 2575 RPM.
The I0-540-AA1A5 was used on the 602P and it was a ground-boosted 290 hp engine with 7.3 to one compression rated at 37” at 2425 RPM.
The TIO-540-U2A was used on the 700P and it was a ground-boosted, intercooled, 350 hp engine with 7.3 to one compression rated at 42” at 2500 RPM.

Years ago Machen Inc. developed an STC to change the S1A5 engine internally and externally to very closely match the TIO-540-U2A engine and it was rated at 350 hp with the same turbos, a similar intercooler, and the rest of the turbo system. The STC calls out to mark the data plate with (MM) meaning Machen Modified so overhaulers will know it is not a stock engine.

The IO-540-AA1A5 was also uprated to 350 hp with a Machen Inc. STC doing only external changes (since it already had low compression pistons).

I think Piper requested that the 350 hp engines they ordered from Lycoming (the TIO-540-U2A) be designated TIO engines and Lycoming agreed to do that as long as Lycoming had control of the engine drawings and Piper could not change anything on the engine package without Lycoming approval.

That is the same agreement that Aerostar Aircraft Corp. has with Lycoming when we order those engines to convert 601P and 602P Aerostars to 350 hp.

The performance of all of the MM modified and the TIO-540-U2A engines is the same. All were shipped with Bendix mags until Continental bought Bendix then Lycoming started using Slick mags. Regarding differences, the TIO-540-U2A engines come with PRESSURIZED Slick mags unless you specify Bendix pressurized mags at an additional cost. Another significant change on the U2A is that they have an automatic mixture control fuel injection servo, which is supposed to lean the engine out in case you suddenly loose manifold pressure. TIO engines are also supplied with max map pressure relief valves (blow off valves) so you can't go much over rated MAP should some part of the turbo system try to overboost. They are optional on the modified IO engines.

O.K. what had me wondering was the initial designation of IO instead of TIO, I wrongly assumed that the engines other than the U2A were not turbo'd and I couldn't figure out why that would have been the case, it didn't seem logical.

When I decided to move back to a twin from my Mooney Bravo, the Baron was my first choice. I was fully familiar with the airplane, had owned a B for a short period of time, and all around, any model is hard to beat. After the Bravo, giving up turbocharging and ready access to the mid-teens was going to be difficult. The one issue with the Baron was the inability of a front seat passenger to move to the rear seats; grandchild issue you see. The Duke was the obvious and desirable answer, but the operating costs, as posted here on BT, were simply daunting.

I was right at the point of buying a nice Navajo when I took a ride in the 601P Aerostar. I had heard about the performance and well, it was real. It took a lot of research to convince myself the airplane was going to be maintainable and parts available, but I got there.

Now, with 60 hours under my belt and a new glass cockpit, I can hardly wait for an excuse to fly. The A* has brought back the "thrill" that flying should be. The TN IO-540's are bullet proof, parts as easy to find as could be possible, and I fly in the mid-teens at 55% power and truing over 190 knots. Fuel burn ROP at that power is about 26, but LOP is the next step as I now have an engine analyzer and getting GAMI's.

Certainly NOT knocking any Baron or Duke, but the A* is the hidden gem of GA.

Jgreen

I sat in one today for the first time, sorry guys.. I'm hard pressed to see this as an upgrade. It seemed smaller than my Baron. There was absolutely no headroom for me in front whatsoever, even after taking off the seat cushion. Climbing through the little door and into the back was no better than my Baron. Is it really wider? doesn't feel like it and didn't feel like cabin class to me. I'm told they fly beautifully and of course, they are fast... but space wise this didn't feel like a "cabin class" upgrade at all... sigh.

I don't consider the Aerostar "cabin-class", but I prefer passenger loading over a 55-series Baron. Not having to climb over the wing is easier for passengers, I think. There is a six inch wide console between front seat passengers. The rear bench seat is certified for three passengers. I've had two 140lb women, and a 40lb three year old back there with ample comfort.

Good that you got to sit in one before getting too excited about the flying qualities and capabilities of the Aerostar. Maybe the Duke, c340, or 58p will be a better fit for you. It's good to have choices. All of them involve some level of compromise.

Is there anything else that will go as fast as a Aerostar and haul 6 people pressurized on the same fuel flow?