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Posted
3 hours ago, Ah-1 Cobra Pilot said:

Lots of weird numbers coming up on this thread.  You can make some pretty good estimates as to horsepower and fuel consumption using these.  (Keep in mind, the numbers presume roughly stoichiometric flow.):

As memory serves me, these are the common Specific Fuel Consumptions for these engine types:  Turbine = 0.43, gasoline recip = 0.36, diesel = 0.34.  All are in lbm/hp/hr.
As you can see, recips are 20-25% more efficient than turbines for the same horsepower.  The big difference is that turbines lose less capability at high altitudes.  You can also make your own estimations, such as this.  "I doubt it’s making 450HP if it’s only burning 17GPH."  Absolutely correct.  17 gal/hr * 6.8 lbm/gal ÷ .43 lbm/hp/hr = 269 hp.  (I use 6.8 lb/gal for jet fuel.  There may be some fudge to that.) 
You can also use this to correlate your fuel burn with your presumed %-power.  i.e. a J-model at 75% power should burn...150 hp * .36 lbm/hp/hr ÷ 6 lbm/gal = 9 gal/hr. 

Again, this is best-case-scenario.  If you run rich, your results may will vary.  I think a little Math can make us all better pilots.  Please try it for yourself.

 

IIRC, this number is called engine factor in the JPI settings, and is 14.9hp/gal which the number for the J is .403.  

There is a thread here about chts and cowl flaps back in 6/18/2011 (don’t know how to link threads, post by Shadrach) that says it’s 14.9 for 8.7 comprssion engines and 15.1 for 8.9.

Posted
1 hour ago, Guitarmaster said:

Seriously bad a**! Looks like it would go great on a Mooney!


Sent from my XT1585 using Tapatalk
 

might work on an M-18 mite. anything else and you're going to need a lot more power.

  • Like 1
Posted
might work on an M-18 mite. anything else and you're going to need a lot more power.
I didn't read the specs. Would be seriously cool to fire up the Mooney with one of those!

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Posted
9 hours ago, Ah-1 Cobra Pilot said:

Lots of weird numbers coming up on this thread.  You can make some pretty good estimates as to horsepower and fuel consumption using these.  (Keep in mind, the numbers presume roughly stoichiometric flow.):

As memory serves me, these are the common Specific Fuel Consumptions for these engine types:  Turbine = 0.43, gasoline recip = 0.36, diesel = 0.34.  All are in lbm/hp/hr.
.....

Using your # for SFC:  My PT6A-35 at FL270 at 700 ITT (780 redline) and 96% Ng is somewhat below peak stoichiometric efficiency (without RVSM I can't go higher in search of peak ITT).  30 GPH x 6.7 lbs per gallon / .43 = 467 shp. 

Let me guess it is 5% lower than stoichiometric. Just my wild guess. That would be 420 shaft hp.  Some power goes to DC generator and pressurization.  Perhaps 400 hp at the propeller? 

I suppose it could take that much power to haul a 4000 pound PA46 through the air at 250 knots.  

I hope a 3000 pound Mooney, smaller overall, with 400 shp would be faster at the same altitude.  It would be hard legally to carry enough fuel to go very far.   

I'd bet Al Mooney never envisioned his sleek 35' wooden wing form carrying a 3368 pound plane at 220+ knots in the FL.  If he had, he would have designed it differently.  

Posted (edited)
On 11/8/2017 at 8:11 AM, Raptor05121 said:

Screw 8 cylinders.

Hear, Hear! Just can't figure out how to put this in my Mooney . . . Then I'd have to do something with the rest of the car, too . . . .

20171021_100704.thumb.jpg.5006d17bf6629edc0c7ee020472f6fa3.jpg

It ain't a turbine, but it's accused of being turbine smooth.

Edited by Hank
  • Like 1
Posted
Hear, Hear! Just can't figure out how to put this in my Mooney . . . Then I'd have to do something with the rest of the car, too . . . .

20171021_100704.thumb.jpg.5006d17bf6629edc0c7ee020472f6fa3.jpg

It ain't a turbine, but it's accused of being turbine smooth.

When it’s not in the shop...

 

 

Sent from my iPhone using Tapatalk

  • Like 3
Posted
Just now, Brandontwalker said:

When it’s not in the shop...

 

 

Sent from my iPhone using Tapatalk

She's a '92 model, I've owned her since '96. My Mooney, not counting annuals, has spent more time in the shop since I bought it in '07 than the car has since '96 . . .

Posted
11 hours ago, Jerry 5TJ said:

Using your # for SFC:  My PT6A-35 at FL270 at 700 ITT (780 redline) and 96% Ng is somewhat below peak stoichiometric efficiency (without RVSM I can't go higher in search of peak ITT).  30 GPH x 6.7 lbs per gallon / .43 = 467 shp. 

Let me guess it is 5% lower than stoichiometric. Just my wild guess. That would be 420 shaft hp.  Some power goes to DC generator and pressurization.  Perhaps 400 hp at the propeller? 

I suppose it could take that much power to haul a 4000 pound PA46 through the air at 250 knots.  

I hope a 3000 pound Mooney, smaller overall, with 400 shp would be faster at the same altitude.  It would be hard legally to carry enough fuel to go very far.   

I'd bet Al Mooney never envisioned his sleek 35' wooden wing form carrying a 3368 pound plane at 220+ knots in the FL.  If he had, he would have designed it differently.  

The equations I am using apply to the engine directly.  I avoid discussing propellers much, as their efficiencies can vary more widely.  Keep in mind, all these numbers are VERY approximate and presume more-or-less flat curves in the changes.

Speed vs. horsepower is also easy to figure out.  If the new Acclaim does 242 KTAS with a 280 hp engine, what would it do with a similar-design 400 hp engine? 

400/280 = x3/2423.  Thus x = 272.5 KTAS, (all else being equal, of course).  So you could add about 30 knots for about 43% more fuel burn. 

 

Posted
18 minutes ago, Ah-1 Cobra Pilot said:

400/280 = x3/2423.  Thus x = 272.5 KTAS, (all else being equal, of course).  So you could add about 30 knots for about 43% more fuel burn. 

So about 30 gph for 270 kts TAS?  With 130 gal tanks that would still be a viable option. 

Posted (edited)
25 minutes ago, MIm20c said:

So about 30 gph for 270 kts TAS?  With 130 gal tanks that would still be a viable option. 

And a 8 year old pilot at most:

900lb useful (about average for an Acclaim)- 780lb of fuel - 56lb of TKS fluid = leaves you with 64 lb for the pilot. 

As to the liquid cooled TSIO-550, IIRC the engine was half baked, lots and lots of coolant leaks, at least on the 414A conversion.

Edited by AndyFromCB
Posted (edited)
On 11/8/2017 at 1:11 PM, jetdriven said:

The sfc of the engine wont change depending on the airframe. It may burn 23-25 GPH at 25,000' but you have to climb there first. And the FF of a turbine isnt much less than cruise on the ground, and 2-3X cruise FF in climb. SO the first hour you might burn off 44-47 gallons. then 25 per hour thereafter. But still, its not even close to a piston engine in economy.

I don't think you'd be burning off anywhere as much as that on a 3368lb airframe. The climb to FL260 should take about 7 minutes with a PT6-135;-) Or not as it torque rolls into the ground. There is a reason why the TBM has 14ft tall tail. Meridian burns off about 26gallons to make to FL250 with decent ATC cooperation.

Edited by AndyFromCB
Posted (edited)
56 minutes ago, Ah-1 Cobra Pilot said:

The equations I am using apply to the engine directly.  I avoid discussing propellers much, as their efficiencies can vary more widely.  Keep in mind, all these numbers are VERY approximate and presume more-or-less flat curves in the changes.

Speed vs. horsepower is also easy to figure out.  If the new Acclaim does 242 KTAS with a 280 hp engine, what would it do with a similar-design 400 hp engine? 

400/280 = x3/2423.  Thus x = 272.5 KTAS, (all else being equal, of course).  So you could add about 30 knots for about 43% more fuel burn. 

 

Exactly!  But let me interpret that differently.  242 is simply the bragging speed of the acclaim - running at 100% power at max altitude.  You can't actually cruise at that.  But 280 is 70% of the 400hp io720, and so you could actually churn that out hour after hour on the 8 cylinder and therefore actually cruise at 242TAS in principle....on 22gph?  That sounds good to me.

And - ...didn't I guess that 400hp would allow a 270TAS mooney?  Now you are agreeing!  So the bragging speed (100% power) of an acclaim with 400hp would be in the 270 range. But more important - you could cruise at 240-245.

Edited by aviatoreb
  • Like 1
Posted
6 hours ago, aviatoreb said:

Exactly!  But let me interpret that differently.  242 is simply the bragging speed of the acclaim - running at 100% power at max altitude.  You can't actually cruise at that.  But 280 is 70% of the 400hp io720, and so you could actually churn that out hour after hour on the 8 cylinder and therefore actually cruise at 242TAS in principle....on 22gph?  That sounds good to me.

And - ...didn't I guess that 400hp would allow a 270TAS mooney?  Now you are agreeing!  So the bragging speed (100% power) of an acclaim with 400hp would be in the 270 range. But more important - you could cruise at 240-245.

Another convert to the IO720 club!

Clarence

Posted
On 11/10/2017 at 3:59 PM, M20Doc said:

Another convert to the IO720 club!

Clarence

I've always liked the Comanche 400.  Even took pictures and marveled over the "Past Grand Champion" one at Air Adventure a few years ago.   I just don't talk about it much for fear your hat won't fit. :>)

Some of these guys on the forum talk about their "other planes" too much already!    (Obviously me included)

Tom

 

Posted
On November 9, 2017 at 2:08 PM, carusoam said:

More about the turbine used on the Luscombe....

http://www.wpsturbines.com/WPS-West_Performance_Systems/About_WPS.html

Best regards,

-a-

Interesting disclaimer from the original builder regarding this listing:

http://aviationestatesale.com/t-luscombe-speedbird/
 

A One of a Kind Airplane… Not Air Worthy… $30,000
E-Mail from the original builder…

I originally built this experimental aircraft as a test bed and proof of concept. I operated it for just over 200 hours, and I attempted to qualify several high time talented pilots in the aircraft.

None were successful at safe and consistent operations. The aircraft was unsafe to operate due to the engine and propeller, and gearbox problems. The propeller has wiring and computer defects. The gearbox has tolerance defects that cause gearbox failures/issues every 50-100 hours, and the engine will flame out if overloaded by the pilot during take-off or climb operations (very easy to do with sudden pitch or propeller control inputs).

Because I determined the aircraft was unsafe to operate after three engine failures and off airport landings, I dismantled the aircraft and it was sold at auction for ~20K. The court supervising the sale ordered that it be sold as parts ONLY, NOT as an aircraft, and that it was to remain a non-flying aircraft.

The purchase was consummated WITH those restrictions in place, and these court restrictions were later ignored by the buyers. That said, I am advising you of the safety defects and issues relevant to the aircraft with the intent that you honestly represent what it is to any potential buyer.

As the original constructor of the aircraft, and the one who grounded and dismantled it for safety reasons, you are advised that I hereby disavow any representation of airworthiness or legality for flight operations at all, and especially in the certified or experimental / restricted / exhibition categories.
  • Like 1
Posted
1 hour ago, Chessieretriever said:

This is what can happen when you get a little help from the winds in this airplane while in the flight levels. Most reliable airplane we have owned so far (we have had more than this one...)

9154W at 345kts GS.jpg

My record GS is 326 so you have me beat....but while exciting is not so informative - a balloon will do 100GS with a 100 knot tail wind.

I want to hear more about the true air speeds and fuel burns you can do!  Please tell....

...also I heard somewhere that there are only 5 liquid rockets in existence.

Posted
5 hours ago, aviatoreb said:

My record GS is 326 so you have me beat....but while exciting is not so informative - a balloon will do 100GS with a 100 knot tail wind.

I want to hear more about the true air speeds and fuel burns you can do!  Please tell....

...also I heard somewhere that there are only 5 liquid rockets in existence.

Im stoked if my rental 172 can hit 110. What fuel burn and true airspeed did you have?

Posted
5 hours ago, Niko182 said:

Im stoked if my rental 172 can hit 110. What fuel burn and true airspeed did you have?

I don't remember the specs, since it was maybe 5 years ago but I remember the day well that I hit 326 - I was at 17k on my way to Hartford and I was not pushing it hard - so I would say I bet I was at 65% at 18gph and likely something like 200TAS.  It was just a fantastic tail wind day.  It ended up such a short flight that basically I went up and then almost right away I had to come down again.

Posted
4 minutes ago, aviatoreb said:

 It ended up such a short flight that basically I went up and then almost right away I had to come down again.

I’d like to have that problem on every trip long distance trip I take. 

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