Dave,

The IO-550 version is better than the IO-360 version in my view despite the added weight. If you want the efficiency, you can run LOP and throttle back. I don't have AC, parachute, or fancy seats, and I put my batteries in the back and a lighter MT Prop on the front. No ballast. My ES with an IO-550 has 1250 lb useful load. 710 lb payload with 90 gallons of fuel.

Who is on a crusade? I'm sticking with facts. Do I think (well built) IVs needs carful attention to the envelope? Yes. Is it for people who either don't or seemingly can't stay within that envelope? No. My guess is we agree on these points. The market for IVs should always be limited to people who are capable of and likely will stay within the airplane's envelope. Others should stay away.

Point me to the accident reports that you believe implicate the airplane. I will read them.

Point me to the accident reports that you believe implicate the airplane. I will read them.

Careful comparing the ES to a Columbia - you will risk torching off a huge diatribe about 400 different airframe mods needed for certification, test pilots total dumping on the original es airframe, etc.

The bottom line on the L4P is that it’s an extremely unforgiving airframe that offers an unmatched performance per dollar ratio (which let pilots in that probably aren’t ready). Additionally, in at least limited cases, inconsistent build quality makes its flight characteristics unpredictable at the edge of the envelope (inconsistent stall performance being the biggie). Last, it handles some scenarios associated with traveling planes (namely ice) extremely poorly, and some of those issues are possibly poorly understood.

Built and flown correctly, the L4P is an impressive machine. However, it needs to be respected and shouldn’t be viewed as the entry level to a pressurized traveling plane to the extent it’s price perhaps allows it to be.

1. I have read the reports. All of them. I have read tons of public information about the IV (and other Lancairs), and I have spoken at length with Martin Hollman (contributed to the design), former Lancair engineers and test pilots, and Lancair IV pilots.

2. I did not ask you to do research for me, I asked you to point me to reports showing the IV is unsafe. Let me make the ask more precise. Show me the NTSB report(s) that show that properly built IVs are unsafe when flown according to the design parameters.

3. Regarding the ES tail, the original IV and ES designs have the same vertical stabilizer. You can confirm this in the build manuals. Obviously, the ES has a much bigger wing and horizontal stabilizer/elevator. I don't know whether the ES rudder is deeper than the IV rudder, but they are the same height. Both a Lancair test pilot during the attempt to certify the ES and a test pilot who has flown many ESs including mine told me that the the ES's rudder authority could be better given the size of the wing and horizontal stabilizer, both of which are much larger than those in the IV. The ES did spin and recover numerous times during certification testing according to the test pilot, but he and other former Lancair employees told me that this was one of many factors that interfered with certification and why the Columbia/Corvalis (a redesigned airplane) came to be. A commercial instructor I flew with who does spin training said he wouldn't want to spin my ES (even if he could) because he would worry whether rudder authority would be sufficient. I can't comment on rudder authority for the IV. My point was that numerous people have said the "tail" on the ES (by which I meant the vertical stab/rudder) is smaller than ideal for the airplane.

3. There is ample evidence in the public record for anyone, whether they have or have not flown the IV, to evaluate the phrase "flying coffin" that you used and that I dont like. The document most cited but apparently seldom read is the FAA's 2010 InFO about Lancairs and experimentals: "Safety concerns of amateur-built experimental Lancair and other amateur built airplanes possessing high wing loading and stall speeds in excess of 61 knots with stall speeds above 61 kts," https://www.faa.gov/sites/faa.gov/files ... O10001.pdf. That document basically says that when an airplane has a stall speed above 61 kts, you have to go faster to keep from stalling than when an airplane has a stall speed less than 61 kts. Indeed. The document further observes that Lancairs (which it singles out) and other experimentals with stall speeds greater than 61 kts were having more accidents than the general aviation fleet and experimentals with stall speeds less than 61 kts. Finally, the FAA opines on the reason: "The FAA believes that this is mainly due to the pilot’s lack of awareness of the slow-flight and stall characteristics of these type of high performance aircraft."

What is the evidence, in NTSB reports, FAA reports, or some other source, that properly built IVs are unsafe when flown within design parameters. Any badly built or badly flown airplane can be dangerous. But again, what is the evidence that properly built and flown IVs are dangerous?

I've often looked at the IVP.
I've now got about 600hrs in the aerostar....
I use the aerostar in a similar manner to what I'd expect to use a IV-P for.
Traveling...

In two cases I think I would have had issues in a IV-P..

1)Climbing out of spinks field near Dallas I was about 300 ft in the air at blue line
I went from blue line to full on stall buffet with break. (A 30+knot change) in about 2 seconds. I shoved the nose over and floated every one in the plane getting back to blue line. I also buzzed the road beyond the end of the field at <200ft.
If the aircraft had unbecoming wing drop/spin tendencies from a a ball centered stall it probably would have killed me.

2)A multi turbo engine is a high strung object. I don't mean to reignite the single/vs twin debate... but I had a full mechanical failure on the critical engine in the Aerostar
and it was a non issue. I still fly singles alas ones that can be slowed down to reasonable survivable speeds in the event of an engine failure. The energy in the crash is proportional to velocity squared.

I would much prefer an ES-P to a IV-P but my understanding is only 5 were ever built.
I think the correct thing in this space if more like an ES, possibly with some complex fowler flaps to get lower power off stall speeds...

(I have a friend that worked at scaled during the Burt Rutan years,,,,says that they often had to increase the vert stab/rudders as the first version was almost always too small...
so rudder size is always an issue...)

Paul,

Spinks is a Fort Worth airport. Nobody from Fort Worth ever describes themselves as being near Dallas. Dallas is a city to the east that sometimes confuses itself with L.A.. We are very happy to avoid it.

Best,

Ed

When I went out to RDD which seems like a fabulous shop. When they locate a donor plane they don’t fly it or recommend it be flown to the factory. They lost at least one trying that. Per the person at RDD they don’t believe the IV’s are safe to fly. They send a crew with a saw to cut the tail and wings off and crate it, or send instructions to the donor on how to chop it up and send it. Not sure what that says about the IVP, but seems to prob be a good idea that they are being decommissioned. Interesting airframe. Very efficient.

A "donor" IV that was improperly built or is otherwise not airworthy is obviously a poor candidate to fly to the RDD's shop for conversion to an LX7. That does not make a properly built and flown Lancair IV unsafe. The concern expressed by the FAA was the number of cases where pilots of high speed high wing loading airplanes made fatal mistakes because they were effectively under-qualified in the airplanes. LOBO worked hard to address that issue the Lancairs.

If someone CADed out the IV design and made more molded parts to make the build easier, I would applaud the effect. I don't think it will happen because RDD has effectively done something like that with the LX7-1 while also making the the airplane more forgiving of piloting mistakes. I suppose it remains to be seen whether folks find that to be a better plane than the IV.

From my reading, it looks like their "from scratch" Lx7 is unpressurized

I wondered why they went non-pressurized. That will remain a selling point for the IVP

And keeps it from competing with their existing line of pressurized, converted from IV/IVP airframes, LX7s. Lack of pressurization certainly simplifies a "roll your own" kit, but at $500K for just the basic airframe, plus paint and interior (which you have to buy from RDD, cost additional), plus options like A/C and de-ice, plus engine and avionics, etc., it's blowing out the top end of kit prices.

And keeps it from competing with their existing line of pressurized, converted from IV/IVP airframes, LX7s. Lack of pressurization certainly simplifies a "roll your own" kit, but at $500K for just the basic airframe, plus paint and interior (which you have to buy from RDD, cost additional), plus options like A/C and de-ice, plus engine and avionics, etc., it's blowing out the top end of kit prices.

BTW, the main innovation they needed is buiildability. An easier build. The airplanes are solid and don't need gimmicks like retractable nose wheels. The need a modernized build.