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vpjr

PT6-20 Cessna U206

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Ahh, kodiak woulda been a good idea. I started with porters, but they are too boxy. So I went with the caravan (that one isn't using its PT6 anymore!) since I have so many pics of it. But the exhaust is actually from an Epic. Well, a microsoft flight simulator model of an Epic. Didn't even notice I wasn't working with a real photograph until after i was done. :)
Dave

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If or when this goes fwd it would use a King Air 90 cowl. I like how Cessna put the air intake and oil cooler scoops on the side to reduce FOD and having the exhaust exit one side reduces the exhaust in the open door problem. Just found 2 -20s with 0 since hot for $110,000 for the pair. An IO-550N conversion for the F model 206 is $63,000

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If or when this goes fwd it would use a King Air 90 cowl. I like how Cessna put the air intake and oil cooler scoops on the side to reduce FOD and having the exhaust exit one side reduces the exhaust in the open door problem. Just found 2 -20s with 0 since hot for $110,000 for the pair. An IO-550N conversion for the F model 206 is $63,000



I'm confused... at first blush, I'd agree that a King Air cowl would give a cooler looking nose and with the underslung air-intake, gives potential for a cool shark's teeth paint job, but I'm pretty sure King Airs still exhast both sides, not just one side?

Also, don't most 206 turbine converstions plumb the exhasut stacks down and out the bottom... sorta-kinda where the cowl flaps are (were)? At least that's what I thinnk I've seen in pictures.

Not that I go looking for them or anything, but I think I've only ever seen one turbine converstion 206/207 ever in the States. They seem to be more of an oddity here then in Europe. What am I missing?

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I would prefer the Caravan style intake and exhaust system. Just the -20 has the exhaust on each side and the King air style cowl provides visibility and location for the air and oil cooler intake. the Soloy has a diffent location for the exhaust. Now the 207 has an extension fwd of the original firewall so Soloy had to create this huge aluminum structure to hold the engine. The engineering would be cost prohibitive. the Soloy mark II looks even better just what is the cost.

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Your photo is of a Soloy conversion, which uses an Allison/Rolls Royce engine that vents exhaust out the bottom.

Sorry, but only a couple of versions of PT6A route all waste gases out a single exhaust, they are installed on Cessna Caravans and Twin Hueys.
That is the primary limitation to installing more powerful turbine engines in Caravans: the exhaust stack configuration.

Note that Kodiak uses - the more common - double exhaust stack configuration and JSPTC jump-masters complained about excessive fumes in the cabin their first season. Last thing I heard JSPTC were working with Kodiak engineers to improve cabin ventilation.

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The conversion process is still going forward. The holidays took some of the time but now the engine is off and the controls and instruments are removed. It will have a LCD engine instrument panel from Electronics International http://www.buy-ei.com/Pages/MVPT/MVP-50T_Overview.html . I am posting pictures of the project on http://picasaweb.google.com/VanPrayJr/DropBox# for those who want to follow the progress. Also see the blog and sign up for the news letter at www.aerialtransport.com Rhinoplasty!!

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The conversion process is still going forward. The holidays took some of the time but now the engine is off and the controls and instruments are removed. It will have a LCD engine instrument panel from Electronics International http://www.buy-ei.com/Pages/MVPT/MVP-50T_Overview.html . I am posting pictures of the project on http://picasaweb.google.com/VanPrayJr/DropBox# for those who want to follow the progress. Also see the blog and sign up for the news letter at www.aerialtransport.com Rhinoplasty!!


Nothing opens like a Deere!

You ignorant fool! Checks are for workers!

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We will have to see. It is easy to do the quick calcs and say we know but you see how well all those guys at Boeing and EADS do at calculating the numbers. I know that the T34A to C model they added weight to the front end, the Porter they moved it Fwd. I always say put the battery in last to get the CG in. The short figures show it lighter than the piston but after cowl who knows. The individual I am working with spent a lot of money making light weight cowls for other turbine conversions then had to add weight.

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Yes, PT-6A usually turns out lighter than the piston engine it replaces.
For example, the first Pilatus Porters were built with Lycoming GSO-480 or IGO-540 piston engines, but when Pilatus installed turbo-prop engines, they had to lengthen engine mounts to balance the airplane.

Most ag-plane conversions also include longer engine mounts.

The most extreme conversion was the DeHavilland factory redesign of the Turbo-Beaver, where they added an entire row of (two or three) seats - forward of the wing - to balance the airplane.

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I always say put the battery in last to get the CG in



Do you plan on using a larger battery, say a Gill G-6381? They way about 70-80 pounds each.
When they converted the DHC-3 single otter to a turbine they moved the battery firewall forward and actually added a second battery, wired in parallel, to keep the airframe in CG.
It also makes for really good starts. With -34s we get 20-22% at spool-up just on batteries.

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That is currently in discussion. We will wait for the final configuration W/B to see what we need. Most Skydiving operators have a start cart so I was leaning to lighter weight of 1 battery. Other types of operators like float plane, or Bush flying would benifit more from the 48V system. I want the APU plug on the right side of the engine cowl. Should I isolate the internal battery from the cart or parallel the internal like a king air? I have had a lot of skydivers help pull the plug early on the Otters. I dont know how the 48V system would handle it.

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I dont know how the 48V system would handle it.



When the batteries are wired in parallel you still only have 24 volts, but you benefit from the increase in amperage.
We can do upwards of 10-12 starts in a day and never use external power.
Like you stated, though, it all depends on weight and balance.

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Should I isolate the internal battery from the cart or parallel the internal like a king air?



I should see if I can copy some drawing for you from the Single Turbine Otter.
The way the Otter is wired you can start the aircraft with External Power plugged in and the Battery ON.
External Power uses the small Pin A to close the relay. The generator comes on line, by its self, after start, but remains isolated from the BUS until external power is pulled.
This gives you the additional boost from external power, for start, but also acts like a Fail Safe if external should fail during start. And unlike the King Air and Twin Otters you don't blow out the electrical system by bringing the generators ON LINE with extrernal plugged in.

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