Norman here, chiming in (again). I'm one of the 601P LOP mafia, along with Glenn, Forrest and Richard, and others!

I really appreciate the engineering of this airplane, it truly reflects the genius of a designer who put a lifetime of experience into his final design.

Glenn said something really interesting to me, and I repeat it to others whenever I get the chance (with attribution, natch!). "Pressurization is a game changer in a general aviation airplane."

And I could not agree more.

But the real thing I like is the flight planning flexibility of the TN intercooled 601P. I can choose to fly fairly efficiently (aka speed AND fuel economy) and very comfortably at any altitude from sea level to FL250. Until there is a TAT TN 58P, I am pretty sure the combination of twin TN-intercooled high compression and pressurization is only found in this one model. There is the Vitatoe P-210 TN for singles, though.

And the handling qualities, well, it flies like a dream. I'll leave it to others to let readers know my qualifications to make that statement!

Norman is modest, he possesses a rare combination of smarts, aviation experience, analytical curiosity and writing ability.

If we are nice, he may re-post his excellent article on Vz.

One long comment:

TIT is the limiting factor in Lycoming / Aerostar LOP operation, especially at higher altitudes. A while back, Craig H (a 700 owner) suggested fine wire plugs.

I took his advice and invested in a full set of Tempest fine wire plugs and saw 20-30 degree lower %#$@ at the same power (FF) settings, as a result I can run a bit (13.5 vs 12.5) more fuel and see +210KTs above 20K'.

Champion Fine Wire plugs might have done the same, but Tempest plugs were a bit less expensive. No regrets.

Bottom line, 7.5-8ktmpg at 200+ KTS is rocking performance, and to echo Glenn, pressurization makes it possible to comfortably pick the altitude with the most favorable winds (and weather).

I couldn't have said that any better

Glenn

One more thing:

Safety

Operating on O2 in the flight levels has the potential for unrecognized Hypoxia.
In the last year a Cirrus and a Mooney were lost after operating at FL250.
I'm guessing Hypoxia.

Flying a pressurized plane, with a working Oxygen Required light, that risk is significantly less. A sudden or fairly rapid depressurization is obvious, ears pop cabin noise changes, and the light comes on. In a gradual loss of pressurization that light is going to alert the pilot well before hypoxia dulls his judgement.

Aerostars have an Oxygen system, and plugging a mask in and turning on the O2 is a fairly simple procedure, but so is descending to a safe altitude.

Engines to idle and nose over to Vne and 25K to 15K is only going to take a couple minutes.

I suppose those that regularly climb into the flight levels get accustomed to dealing with a mask and hoses and figure they can manage the risk, personally, the idea of climbing up to FL250 on O2 gives me the willies.

Forrest,

Please give us some background and your opinion of the EVS system you have. Thanks.

Mark

Before we place too much importance on turbo-normalizing, lets look at the actual difference in efficiency.

Lycoming data gives the difference in efficiency between the turbo-normalized 601P engine, with 8.7/1 CR, vs. the ground boosted engine with 7.3/1 CR. If you pull the same 175 HP the turbo-normalized engine will burn 12 GPH and the ground boosted engine will burn 12.7 GPH.

Having up to an extra 60 HP per engine available with the ground boosted engine, means better take-off performance, single engine safety, single engine ceiling, all engine climb rate, and the optional 850 lb. Increase in useful load, etc. Do all of these advantages make it worth the slightly higher fuel burn for the same cruising speed? Some owners think so. Engine maintenance costs are the same for the 290 HP engines or the 350 HP engines.

I totally agree with Glen and Norm that pressurization is a game changer.

Best regards,
Jim

It is also worth note that 700 drivers attract better looking women, are dozens of IQ points higher, and have, on average, much larger genitals.

Before you little HP guys get upset, just stop it. I'm representing scientific fact here.

Jim you forgot the additional speed available from the 350 Hp engines. It was very hard to pull back and go slow. I gave up on LOP and usually ran ROP at the higher speeds available with the 350 Hp engines. The 700 was the best plane I ever had, very well built, and no comparison to anything else that's piston powered. I frequently passed a lot of the single engine turbo props like the Meridian and the Pilatus.

Andy

Jim, excellent performance form the 700's, but I also had at least two potential buyers on my 601P who had had 700's in the past and said that pulling 350hp out of them made them less reliable. Said the 601P's will make TBO without top end work, whereas the 700's won't. I have no clue if that's true, but that was their statement.

Thoughts on this?

Hi Adam,

When I worked as an A&P doing annuals on Aerostars back in the 70's the engines would start needing a cylinder at about 1000 hrs. At the next annual they needed 2 or 3 cylinders and at 1500 hrs. they would need another 3 or 4 and owners said,"just get them overhauled." I see the same thing with the 350 HP engines. That being said we just had a customer in for annual and he had 1600 hrs. on both engines and all 4 turbochargers. He had a broken oil control ring on each engine and when we pulled the cylinders both engines needed cams and lifters. We had one Super 700 owner that used the airplane 600 hrs. per year and he went to TBO of 1800 hrs. on both engines. I think corrosion due to lack of use is the number one cause of premature cylinder work and overhaul. Almost all of the cylinders we pull off show signs of rust and pitting.

Best regards,
Jim

Hi Andy,

Yes I agree pulling back and going "slow" 200 ktas, is hard to do. I have to tell a story about Forest an Aerostar owner and all around good guy. He brought his 601P out for winglets and we found some maintenance issues he wanted fixed. As luck would have it we had a Super 700 that he could rent while we had his airplane. I had him take the 700 on an extended pattern so I could show him how to save fuel in the 700. He flew to Florida then up to Virginia in one day then back out to Idaho a few weeks later. As I recall, not one leg had a ground speed of under 250 KTS! When I asked him why he didn't throttle back and save fuel, he said, "I was in a hurry!"

Best regards,
Jim

Jim, excellent point. It's always a trade off. Good to have options.

In defense of our 601P's I will add a good part of the increase in useful load goes towards carrying extra fuel.

I do not have an aux tank, a 1,000nm (no wind) trip is doable with an hour reserve at the end. Of course we are going slower than those with 350hp engines but depending on your mission profile, not having to make a fuel stop will more than make up for that.

Glenn

[quote="Glenn Chong"][/quote]
Jim, excellent point. It's always a trade off. Good to have options.

In defense of our 601P's I will add a good part of the increase in useful load goes towards carrying extra fuel.

I do not have an aux tank, a 1,000nm (no wind) trip is doable with an hour reserve at the end. Of course we are going slower than those with 350hp engines but depending on your mission profile, not having to make a fuel stop will more than make up for that.

Glenn

Hi Glenn,

I agree options are good. The 700 can have an 850 lb. useful load increase. Filling the aux tank with 45 gal. (270 lbs) still leaves 580 lbs of extra useful load. Mostly the extra fuel is only required if you want to go faster. I agree that on a 5 hr. flight the 700 will burn 7 gal more total fuel (1.4 gph) going the same speed as the 601P.

With intercooling, the 601P is a great airplane. The really good news for Aerostar owners is that they can upgrade to more power, or more fuel, or more useful load, or increased cabin pressurization, any time they need or want the added capability.

Best regards,
Jim

Between Craig's scientific evidence and Jim's embarrassing (but accurate) memory of my tendencies, I am totally busted.