LS-1 from Robinson for RV-10

[rv6ejguy]

I agree that the overhaul costs for the Lyc are overstated on Robinson's site. There is also an eror in one of the cruise speeds, should read 150mph, not 250 Pretty hard to get a Seabee to do 250! We must compare new to new here with regards to prices. I see the initial costs about the same. Overhaul costs will be way lower on the V8.

Diesel engines are in the .3-.34 range of SFC. Some stationary ones are as low as .265. Some aircraft engines achieve as low as .36. I calculated the SFC for the LS-1 using figures in a magazine article giving the fuel consumption, MP and rpm and extrapolating from the GM dyno curves. With the compact chamber and 10.1 CR EI and EFI running inclosed loop, .385 is certainly possible. Our Sube gets .42 leaned to 13.8 AFR.

The LS-1 and LS-6 certainly do produce the power stated and the numerous endurance racing wins prove its durability. There is no history of HG failures on these engines to my knowledge. They have a reputation for being bulletproof.

The longblock weight IS 390 lbs. GM lists the all up weight with accessories as 457lbs. A Lyc. IO-540 weights between 405 and 430 bare, depending on model. Add accessories and you are at 430-455. On the LS-1, the redrive, rad and coolant will add 75 to 100 lbs. All things being equal, this is about how much extra it will weigh over the Lyc.

I'm using a Sube EG33 in my -10, not an LS-1 but I don't see quite so many negatives here other than the weight.

[Dave Hertner]

I for one would like to thank you for the detailed and thoughtful responses that you provide in this and other forums where you participate. I have a lot of respect for people who have actual experience in the subjects they talk about.

I was at a Canadian Recreational Aircraft Assn. meeting the other day at the private airstrip of a Dr. Henry Chapetski. In his hangar was a beautiful Republic SeaBee that has this Robinson LS-6 conversion. We talked at length about his decision to put this conversion in his plane. He has a very good relationship with Mr. Robinson and is genuinely pleased with the results.

As others who had flown in to the meeting were departing the field Dr. Chapetski fired up the SeaBee and let it warm up a little. Boy did it purr. You couldn't hear the engine over the prop noise when it was idiling. He then took off and did a couple of flybys. There wasn't a person there that didn't want to put one in their own plane.

It is important to note that this engine/PSRU combination was designed specifically for the SeaBee and it has a significantally longer final drive due to the design of the airplane. He has another shorter drive that is designed for tractor applications. I have seen this installed in a local Murphy Moose.

I have also had conversations with (LL8 - Vortec I-6 that have much the same archetechure as the LS-1/LS-2/LS-6 engine) engine designers at GM who said that their testing regime has a number of engines put through a dyno testing routine that is the equivalent of 2500 hrs use. A representative group of these tested engines are then continuously run at full throttle for another 2500 hrs. They have yet to have an engine fail or show any adverse wear. These are impressive numbers indeed.

[rv6ejguy]

Thanks for the kind words and another positive voice from the alternative engine wilderness. Many of the cert guys here seem to think that these engines are going to frag in a few hours at WOT yet can't produce any evidence to support such views. 2500 hours at WOT is not too shabby!