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Hi Gerry,
I have my L4P registered at #3400 gross, which I think is recommended by almost everyone that I talked too. My airplane is heavy and seams to fly with an aft CG. I have flown it at #3550 lbs. with talk-offs at DA of 8500 ft. It does take longer to get flying but flies fine (210 hrs).
I just talked to a Turbine guy that is flying his at #4600 lbs Gross and he says it climbs and flies fine (My mouth was hanging open). The wing seams to be strong enough but the two concerns are the landing gear and the stall speed, especially at clean take off. I now rotate at 80 Kts to allow for turbulence and aileron authority.
The Landing gear must have been designed for a drop rate or G loading for a hard landing. So even at the original #3000 lbs Gr. there should be some safety factor. Does anyone know the design numbers for the gear? I know of one accident that happened many years ago when a pilot took off for the first time with 4 people and hadn't trimmed it for that. It over rotated and he pulled the power. It dropped in from several feet up breaking the noise gear and engine mount. The mechanic that repaired it called the factory to get new parts for the main gear a was told that if the gear didn't come through the wing that is was still OK. I don't know for sure if this is a rumor or the truth but I also know that the very early gear box did have some failures at the fuselage attachment and since being redesigned I haven't heard of that type of failure. Anyone know about that? One better make a very smooth landing if your at those #4000 lb weights. It would be interesting to know what the stall speed is at #4600 lbs.?
Keep the Mach Up,
Jim Hergert
N6XE, "An Sex Y" L4P
When I first researched IV-P, in the early 90's, the gross weight according to the factory was 3000 lb, then a few years later, listed at 3200 lb. This was the weight we used when we had our plane's final inspection. I now note on the Lancair Website that the maximum gross for the IV-P is listed as 3550 lb. It is also my understanding in talking to other builders that it is possible for a builder to certify a higher gross simply by flying the plane with greater weights and re-doing stall speeds. My questions to ask the opinion of the LML group are as follows:
1. Does the 3550 lb gross weight apply to all IV-P's or just to the turbine IV-P's?
2. Have any builders already increased the maximum gross of their plane, and if so, what procedures did you follow to make it legal?
3. I have heard builders express confidence that the IV-PT can handle a max weight of 4000 pounds, has anyone flown their plane with that much weight?
Gerry Leinweber, C-GLFP
150+ hours and climbing
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