Changing cg for heavier firewall forward weight

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Daleandee

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The corvsir sparked my interest butvthe conversion cost snd low hp was not attractive. That and the old technology cylinder heads and old core parts again made it un desirable to me.
I'm guessing you meant to type Corvair. I like the engine immensely and find the 3.0 120 HP to be very reliable and the price (at my time of purchase) was very reasonable considering most alternatives in the same price range were VW based which wasn't enough power or engines with ongoing concerns I didn't want to deal with.

But the Corvair is a heavy engine and in my aircraft I did have to make a change to get the CG to come out correctly but all that was needed was a battery move to the rear. I don't think you are going to find it too difficult to make your project work.
 

BBerson

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Wing forward sweep might be easier than moving it. John Roncz had considerable forward sweep in his design. (never built)
 

Lendo

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Brisbane
S. I run the numbers for the Vision and their all pretty good and I had some good discussion with the designer Steve Rahm when I was in the States, as I have the plans. Steve suggested at 100 hp the Subaru was a bit lethargic on a hot day, make of that as you wish. Also the weight is a little over Light Sport ( which I was hoping to achieve) and stall speed is at about 50 knots. He used NACA 63A 415 to 63A215 Tip ( also good choice), with the new Carbon Rod Spar it should be lighter, I believe Scott supplies those premade because of concern about build quality. I often wondered how light the plane would be built out of Carbon and Infused.

You have received some very good suggestions/information in this discussion.
George
 

rv7charlie

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I'd have to question the statement that '150 lbs is negligible', and the false assumption that added engine weight is measured *at* the firewall. Yes, you can add that much weight to the nose of *some* a/c, but not all. Even if the airframe can take another 150 lbs of engine, can it also take an additional 120-150 lbs of fuel, to feed the added HP? Is there any place to put the fuel? The dominoes start falling quickly....

If I were looking for more HP in something like a Vision, I'd be looking for more current tech. I realize that the Sube is already in the shop, but if the Vision is what you want to build, perhaps selling the Sube & going to a lighter engine with useful HP might make more sense. Have you looked at the Yamaha snowmobile engines? The old R1 engines are around 140 HP, and the core engine is, IIRC, around 130 lbs. Later models are up close to 200 HP, with not a lot of weight increase.

Charlie
 

slociviccoupe

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Palm Bay Fl.
I'd have to question the statement that '150 lbs is negligible', and the false assumption that added engine weight is measured *at* the firewall. Yes, you can add that much weight to the nose of *some* a/c, but not all. Even if the airframe can take another 150 lbs of engine, can it also take an additional 120-150 lbs of fuel, to feed the added HP? Is there any place to put the fuel? The dominoes start falling quickly....

If I were looking for more HP in something like a Vision, I'd be looking for more current tech. I realize that the Sube is already in the shop, but if the Vision is what you want to build, perhaps selling the Sube & going to a lighter engine with useful HP might make more sense. Have you looked at the Yamaha snowmobile engines? The old R1 engines are around 140 HP, and the core engine is, IIRC, around 130 lbs. Later models are up close to 200 HP, with not a lot of weight increase.

Charlie
I actually have. Ive also looked at the 1812cc engine offered in the yamaha watercraft. I know them well. The apex snowmobile engine very similar to the 20v r1 engine. The ski engine makes 260 hp at 7400rpm. But its very thirsty.
 

rv7charlie

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Define 'thirsty'. :) I suspect that if you compare its fuel consumption to, for instance, a Continental IO470 (same HP rating), its fuel consumption will be at least as good, and quite likely, a lot better than the Continental. Having said that, there's a room full of dominoes to fall if you install a 260 HP engine on an airframe designed for 100 HP, only one of which is the basic engine weight. Torque loading into the airframe, VNE questions, etc etc. That's why I was pointing to an engine that would fit within both the weight limitations, and common sense limits to HP increases for a particular airframe.
 

wsimpso1

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Billski i was hoping for your reply.
Thanks...

Any other 2 seat side by side composites out there?
Have you checked out Azealea Aviation's Sabrewing? Nice looking bird, several flying, Bill and Kyoung Clapp are contributors on here, go to the shows, and the airplane's look quite good. They have a regular feed day at 15J if it is in range for you.

Billski
 

BJC

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Good looking plane but kit built not plans built.
Really wish there was an extra 200 plans built.
Same with the glasair
You may be able to find unused Stephens Akro plans, and stretch them for two seats, or buy new plans from York LASER Z SPECIFICATIONS / PRICE LIST for their two seat Z 2300 and modify for the lighter engine, or build the Z 200 as a single seat.

There also is the DR-109.


BJC
 

wsimpso1

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I was just going to suggest that if tube and fabric is acceptable, the DR-109 is quite the bird in two seats, DR-107 for a single seater.
 

TFF

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I would go for the Lazer. There would be no Extra if there was no Lazer.


There is a DR-107 at my field. I like it, but I think it is too small. A couple of more ft of wing and fuselage would make it groove better. I think it could give up some of its nimbleness and be a little better overall. I don’t now if the 109 compares
 
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