Turbine Twin Velocity

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rbarnes

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Aug 28, 2015
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413
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Texas

I knew the plane had been under development for years now with the plan to use a pair of 260hp PBS turbo-shaft engines.
Nice to see the new updated website has a page dedicated to it showing a good bit of progress. Not sure I think much about that "flip up" 2nd row seat to access the 3rd row.

6 seats but nothing about pressurization, A/C, or 3,000 mile range unfortunately ...
 

billyvray

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Aug 17, 2005
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963
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Newnan, GA
Wow. You can't hide money....
I like the little turbo prop. I echo the short tail moment concern. I wonder how long the fuel would last...the standard v-twin has a capacity of 95 gallons and 1150 mile range on the IC engine version.
 

rbarnes

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Aug 28, 2015
Messages
413
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Texas
Wow. You can't hide money....
I like the little turbo prop. I echo the short tail moment concern. I wonder how long the fuel would last...the standard v-twin has a capacity of 95 gallons and 1150 mile range on the IC engine version.

You can tell from the pics that the wing and wing strakes are much bigger than a normal XL Velocity. I would estimate 150-200 gallon fuel in this version.
 

TFF

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Apr 28, 2010
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17,314
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Memphis, TN
To use a turbine to its potential, you have to climb high. Take advantage of true airspeed. Flying consistently at 20,000-25,000 ft.
200 kt indicated at 20,000 is 290 kt. That’s how you take advantage of a turbine. At 10,000 ft TSA on 200 would be 245 kt; that’s a lot of free speed, but 45 kts more is not chump change. If they plan to fly it right at RVSM cut off, they will be above 300 kt true. A piston can get that high, but it wastes a lot of time in the climb, even if turbocharged. Getting to 20,000 in 20-25 minutes is a huge travel advantage.
 

JMyers1

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Jul 30, 2021
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75
Location
Denver
Anyone heard any news on this? I think the project is neat, anyone have specific fuel consumption on those PBS engines?

I assume it will perform a bit better than the XL with a 550 but less fuel efficient, probably less range, more expensive engines, and higher overhaul/inspection costs. That could be a fair tradeoff for the cool factor, reliability, and simplicity of a twin turboprop.

The XL with a TSIO-550 has a 250 knot cruise speed at FL250 and a 1250nm range. It makes about 230hp up there, so I would guess based on some (probably inaccurate) mental math 260-270 knots for the turboprop twin. Even if it has 2/3 the range that's still pretty good (the plane has no bathroom anyways!).

If those engines can make 200hp at FL240 (no idea if they can, that would be 77% power) that is 400hp minus the loss in efficiency from splitting the engine into two.
 
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Mad MAC

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Dec 9, 2004
Messages
871
Location
Hamilton New Zealand
Have to admit, a single centre fin on that layout is fairly pointless, just need the central underfin with a retracting parking wheel.
Without resorting to a FBW controled fin on the nose or a Gippsaero GA8 sized fin, I think the only way to get sufficient leverage is wing tip speed breaks specifically for the engine out case i.e. still use the fin for the rudder import.
 
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