REFLECTOR: Re: Turbine XL

Wayne Lanza wlanza at bellsouth.net
Wed Jul 14 20:31:20 CDT 2004


  I am some what versed with the Allison B17F and would offer the  
following operational facts.
This is the same engine you may have seen as a conversion for the  
Bonanza, C210, Glasair 3
and several other aircraft. The core engine is basically the same as  
used in many helicopters,
most notably in the Bell jet ranger. The B17F is the only variant in  
the lower HP ranges that is
set up for propeller use. The engine will weigh about 250# installed  
and would be a reasonable
fit/conversion for an XL. The B17F is rated at 455HP and will maintain  
about 300HP at 20K feet.
Operation at altitude will get the miles per gallon number competitive  
with a recip, but you will
have a flight duration of about 2 hours. That's the good news...
  The caveats are:
* Engine cost - $50K for a decent run out, another $50K for an overhaul  
(typical - varies with core
condition). If you are interested in a new engine - forget it, they  
won't sell to home builders (a new
engine is about $350K!!) If you find a rebuilt, expect to it to be  
$150K to $250K.
* Fuel consumption, which is about 50% higher than a sloppy recip  
(typical SFC for the B17F is
0.72P/H/HP - Lycomings are good for 0.52 or less).
* The propeller will have to be a custom - No you can't put an Ivo on  
it!! I got a quote from MT, the
correct prop will cost about $15K plus governor (remember that this is  
a constant speed engine).
* Correct use of a turbine has been problematic - they are easily  
damaged by unqualified operators.

  The bottom line is that turbines are not yet ready for us, we all wish  
otherwise... If you haven't heard
the facts about ATP or whoever they are calling themselves now... DONOT  
be mislead by these guys!
To be kind they are thieves and Bull Sh--ers, We have three of the T62  
engines that they use as cores.
They run great, are light weight, very small and extremely simple - but  
burn all of the gallons per hour!
ATP has somehow bent, stretched, and found ways of defying the laws of  
physics and metallurgy - all
the while building a turbine engine in their garage that burns less  
fuel than a piston engine! WOW, do
you know what this means? GE, P&W, Garrett, RR and Williams have a lot  
of explaining to do!!

Fly Safe & see you at Oshkosh,
Wayne Lanza
Composite Design
________________________________________________________________________ 
_______

On Jul 14, 2004, at 6:56 PM, Greg Poole wrote:
>
> No, not contemplating a turbine Scott unless they ever approach
> piston/rotary running cost (including overheads)....but ...curious
> again...what makes the RR Model 250-B17 so special?  (read; HP? fuel  
> burn?
> W&B effect for a Velocity?) ...you don't have one or two for sale do  
> you??!
> ;^)
>
> Greg



More information about the Reflector mailing list