LS-1 from Robinson for RV-10

[rv6ejguy]

Check out this site: www.v8aircraft.com. Developed by a P Eng. Accumulated over 1500 flight hours in several Seabee airframes. These look very professionally done and no outlandish claims. Was a good R&D article in the Canadian Recreational Flyer RAA magazine May/June 2004 on them. Brand new crate engines, can use C/S prop. Not cheap but neither is a new IO-540.

[gmcjetpilot]

Wonder what the whole thing weighs. The question to ask is what was the before (Franklin 6 cyl) and after empty weight of the SeaBee conversions they did. The installed before / after weight is the only real way to compare. The reduction drive looks like a real hunk of machinery. I like the sound of the prop going supersonic on take off. Clearly with the higher reving auto engine conversions (hyd) prop control is a must to get the performance. I am not a fan of electric props. This could be a cool engine for a WWII fighter replica.

Price for their Conversion is over $30,000 and they say they will not sell the reduction by itself. For the record a brand new crate LS1 third generation long block sells for about $6,500. What do you get for 30K? I suppose if the weight is acceptable for a RV-10, and they make a $30,000 kit for the RV-10 that includes all the parts: engine mount, exhaust, heat exchangers, systems, like an egg subie kit, it would be a deal. My guess it is too much weight to hang on the front of a RV-10. Also I think the only complete kit they have is for the SeaBee. Interesting. The issue of getting this relatively physically large engine package and heat exchangers (radiators) under the cowl of a RV-10 might be a bit of a challenge.

Regards George

[Rotary10-RV]

Price for their Conversion is over $30,000 and they say they will not sell the reduction by itself. For the record a brand new crate LS1 third generation long block sells for about $6,500. What do you get for 30K? I suppose if the weight is acceptable for a RV-10, and they make a $30,000 kit for the RV-10 that includes all the parts: engine mount, exhaust, heat exchangers, systems, like an egg subie kit, it would be a deal. My guess it is too much weight to hang on the front of a RV-10. Also I think the only complete kit they have is for the SeaBee. Interesting. The issue of getting this relatively physically large engine package and heat exchangers (radiators) under the cowl of a RV-10 might be a bit of a challenge.

Regards George

George,
This was what got me started on the Vesta V-8 also. The weight of the raw LS-1 isn't bad but the redrive (probably a Hi-Vo chain) is heavy. fitting in the rads (in the cowl) is equally a difficult project.
Bill Jepson

[rv6ejguy]

The LS-1 long block weighs around 390 lbs., very close to a 540 but of course the redrive will likely add another 50, rads and coolant 30- likely this would weigh 60-80 lbs. more than a IO-540 using about the same prop and accessories. At least the price is in the ballpark with a new 540. Fuel burn from some of their previous documentation I have read might be slightly less to offset that total mission weight but certainly some ballast would have to go aft to correct the C of G.

The redrive has to be a pretty beefy piece to take up to 450hp with the blown versions. I agree, a bit on the porky side for an RV10 and rad packaging would be interesting. I think the big part of the package price is the engineering, testing and fabbing of the redrive. They have also spent a lot of time modding the OE ECU to stay in closed loop past 70% throttle to get the lower fuel burn and have removed the fly by wire throttle also.

They'll probably have to develop a complete FF package to sell them for this market and be priced under $40,000. At least this one has a fair amount of flight time on it and has some proper development and engineering behind it. The integrated a/c might be nice for some in the hot/ humid climates but there is even more weight up front.

One guy stuck an LS-1 on a -7A! Must have taken some serious tail ballast for that one!

[Rotary10-RV]

They'll probably have to develop a complete FF package to sell them for this market and be priced under $40,000. At least this one has a fair amount of flight time on it and has some proper development and engineering behind it. The integrated a/c might be nice for some in the hot/ humid climates but there is even more weight up front.

One guy stuck an LS-1 on a -7A! Must have taken some serious tail ballast for that one!

I have to agree there! The engineering on the redrive units however, no. The Morse Hi-Vo chain/gear drive has been around to use since the 1966 Olds Toranado. It is an excellent transfer device having many of the attributes of gear drive while being more flexible. I like it. That being said it's never even claimed to be light. The drive sprockets must be steel for wear. If the redrive weighs less than 65 pounds I will be impressed. I have a hard time with the idea of a V-8 RV-10 fitting in the stock cowl unless the radiators are remote mounted. A P51 style set-up would be ideal since you could move some of the weight rearward to help on W&Bal issues. The floor of the RV-10 is NOT a great candidate for the scoop treatment though. There are a great many stiffening ribs under the baggage area to transfer loads. You could certainly re-design the area (sorry Van) but it would be a big job. I also have a problem with the pricing.
260 HP Lyc IO-540-D4A5 straight from Van's 39,875.00 brand spanking newand it bolts up. I said previously that if you aren't doing it to be different and can't do most of the engineering yourself the conversion won't be economical. Egg soobs are a good buy since they are a proven FWF package. They have inched ever closer to lyc prices though. These comments are made by a dyed-in-the-wool conversion engine supporter. The guys need to have these things FLYING in the plane you are building before they are even worthy of consideration. The SeaBee conversion is neat. A flying version of the engine in an RV-10 would be wonderful. You should let them be the development engineering team however. If they want to ask those prices for the machinery the onus is on them to prove it works.

Bill Jepson (see George I'm even arguing for a Lycoming! At least until the conversion is proven.)

[rv6ejguy]

Yep, they need one installed in an RV10 to prove it and get all the installation kinks worked out. The price is a little steep for what you are getting here. Pretty cool though if you wanted to set some time to climb records with the 405hp version. Sorry about that one Van, I know, I know, 260hp maximum.

We're mounting our rad scoop much further forward, under the wing, where the main central tunnel is. Bill Kay is working with us on the rad and other coolers.

The EG33 is only 265 lbs. for the long block and packaging is easier than a V8 also.

What does the 20B longblock weigh?

[rv6ejguy]

Originally Posted by Rotary10-RV

I have to agree there! The engineering on the redrive units however, no. The Morse Hi-Vo chain/gear drive has been around to use since the 1966 Olds Toranado. It is an excellent transfer device having many of the attributes of gear drive while being more flexible. I like it. That being said it's never even claimed to be light. The drive sprockets must be steel for wear. If the redrive weighs less than 65 pounds I will be impressed.

I think the amount that the thrust line had to be offset and reliability being the top design concern here made the use of a Morse chain the best bet. All chain and gear drives use steel gears. I think the Morse would be one of the lighter choices here given these two concerns. The biggest weight percentage in redrives is usually in the case/ housing, not the gears or chains. Yes, this drive may weigh 65 lbs. plus but so do most of the other units that are rated for this hp level. The Marcotte 300hp drive that I use is 46lbs., the 600 hp one is 62.

I did read some more on the total LS-1 package here. It appears they are using the stock manual transmission flywheel and many of the OE drive accessory pulleys which are iron or steel. I'd revise my estimate therefore that this basic package would be 80-100 lbs. heavier than the Lyc., ready to swing the prop. Probably have to use a composite prop like MT (44 lbs.) and have the rad mounted some place other than firewall forward to correct C of G. Even if the engine burned 2 gal./hr. less than the 540 (unlikely in my view), a typical 3 hour mission profile would require maybe 36-40 lbs. less fuel so you'd still have 40-60 lbs. less payload to stay within Van's gross weight limit. Maybe acceptable for some if the seats are not filled with heavy people on regular basis. Not sure what the Hartzell 2 blade C/S prop weighs for the 540?

Still an interesting conversion and I bet it sounds awesome.

[rv6ejguy]

I ran some calcs on the LS-1 and came up with a cruise SFC of .385 lbs./hp/ hr. for it. Not bad. So it does look like it would burn about 9% less fuel than an IO-540 equipped with mags. This would not offset the increased installed weight over the Lyc. The Lyc's SFC might be improved somewhat as well with EI.

[Rotary10-RV]

Originally Posted by rv6ejguy

Yep, they need one installed in an RV10 to prove it and get all the installation kinks worked out. The price is a little steep for what you are getting here. Pretty cool though if you wanted to set some time to climb records with the 405hp version. Sorry about that one Van, I know, I know, 260hp maximum.

We're mounting our rad scoop much further forward, under the wing, where the main central tunnel is. Bill Kay is working with us on the rad and other coolers.

The EG33 is only 265 lbs. for the long block and packaging is easier than a V8 also.

What does the 20B longblock weigh?

RV-6, The 20B "longblock" is really the entire engine assembly. The 20B with the standard iron end plates is 297 pounds. There are at least 3 sources working on production of aluminum end plates, (Mazda used them on their LeMans winning 24 hour endurance racer but they are too expensive for typical production), and with the aluminum end plates and intermediate housing the 20B will be a whopping 40 pounds lighter. Approximately 250 pounds. Al G installed a 20B in his Velocity and dynoed it with a decent injection and somewhat restrictive exhaust at 290 HP at 6800 RPM. I plan a max of 6000 to limit to 250. Mistral engines has a listing of weights and hp for their 2 and 3 rotor engines including the reduction drive. WWW.Mistralengines.com check under "products/general/engine weight comparison chart". They list a 20B based G300 engine weight at 350 pounds.
I agree the Subaru is an easy package to work with being a flat 6 and therefore "aircraft engine like". The rotary is even smaller (in overall size) the ancilliary systems are the big deal, for all conversions really.
Bill Jepson
Rotary10-RV

[tloof]

I have never seen so much Balony as the operating costs that Robinson quotes on the LS1 V8!!

To start off, they state an I0-540 overhaul cost to be $40,000. What a crock, when a BRAND NEW one from Van's is $39,875. Not to mention that if you buy a core engine and rebuild it with six NEW Millineum cylinders you can still do an entire overhaul for no more than about $15K total (or a total envestment including core cost of around $25K.

Second, there is no way in **** that this engine will do better than a cruise SFC of .45 lbs./hp/ hr (.385 lbs./hp/ hr is totally absurd to believe when pulling 75% power of around 260 hp or so) when the best any Diesel engine can get is around .39 lbs./hp/ hr (no gas engine is going to match a Diesel). The 10 gal/hr fuel consumption value they give for cruise will be EXACTLY the same as what the Lycoming burns, which is 15 GPM. Horsepower is horsepower no matter what, and if the LS1 is pulling the same power as the O-540, then it will eat close to the same amount in fuel.

The whole operating cost comparison is heavily misrepresented to make it look like the LS1 V8 conversion is better, when in fact it is FAR WORSE. The upfront aquisition cost is greater, the TBO is less, the overhaul cost is not accurate, and also the installed weights are not correct (the base longblock LS1 with NO accessories is closer to 450 lbs, rather than the 390 lbs as stated earlier). The actual overhaul cost/hr is more like $7.50/hr as opposed to Robinson's stated $20/hr (the V8 is $6.67/hr according to them, which is **** close to what the Lycoming costs/hr).

There is not one shred of truth in what I see on Robinson's website. The LS1 V8 conversion will end up costing WAY more than what a Lycoming O-540 will, and will only end up being one HEAVY PIG in an RV10...in the end you WILL probably need the 350 hp it supposedly can make just to match the lower powered 260 hp O-540 (I personally doubt the LS1 V8 can sustain any more than the 260 hp the Lycoming O-540 makes simply due to the head gaskets blowing all the time at high % power loadings...the same problem that led to the development of cylinders attached directly to the heads on most all aircraft engines).