Bobby,

 

It is amazing how much it costs to go faster.  50 hp costing 4-5 gal/hr is only good for an additional 11 mph!  5 gallons to go 11 miles…that is expensive!

 

I wish I had paid more attention to the drag on my bird!  :>( 

 

Weight helps in the climb.  I probably was able to save 10 lbs of empty weight building the plane over 7 years.  I went on a diet and exercised a little and lost 30 lbs over the last few months!  I have been trying to think of a way to bring this subject up with my wife……!    :>)

 

On second thought, it climbs pretty well.

 

Bill

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, June 08, 2015 11:10 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Using Van’s climb performance numbers I’m closer to the 210HP engine than the 230HP. Maybe 215HP net.  The super charger mechanical losses may be as high as 10HP and the air temperature rise could be another 10 HP. Water injection cools the intake charge but displaces O2 so I really don’t know. I’m sure the gearbox has mechanical losses also. So 230-240 HP before operational losses seems reasonable.

 

 

 

Light Weight 2200 lbs	210 hp	* 235 hp	260 hp
Speed
Top Speed	200 mph	204 mph	211 mph
Cruise [75% @ 8000 ft]	190 mph	194 mph	201 mph
Cruise [55% @ 8000 ft]	170 mph	174 mph	180 mph
Stall Speed	57 mph	57 mph	57 mph
Ground Performance
Takeoff Distance	475 ft	415 ft	360 ft
Landing Distance	500 ft	500 ft	525 ft
Climb/Ceiling
Rate of Climb	1,400 fpm	1,669 fpm	1,950 fpm

 

 

 

Bobby

 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, June 08, 2015 10:20 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Bobby,

Wouldn’t you think that equates to about 250 hp on take off??

Bill

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, June 08, 2015 9:47 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Bill,

 

I believe my normal fuel flow is actually closer to 23gph at 7000 rpm\ 38” MP and 12.5 FA. I don’t really look at it anymore during takeoff. I’ll pull current engine logs when my AFS-3400 EM gets back from repair. It decided to start rebooting every few minutes.  I can run 40.5” MP / 7500 rpm at sea level but avoid the top limits.  My MT controller is within 100 rpm.

 

Bobby

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, June 08, 2015 8:46 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Bobby,

You can take my fuel burn numbers with a grain of salt.  The EM-2 is not completely calibrated for fuel flow.

 

By the way, is your prop controller dial calibrated to the prop rpm you actually get?  Mine is not and I think that Mark’s may not be either based on some of the things he has written. 

To get 7100 engine rpm, which is 2500 prop rpm, I have to set the controller for 2600 for takeoff.  2400 setting will get me 6500, etc..  Early on, I thought that the tach on the EM-2 might be off, but I decided that to be pretty unlikely.  However, there is a disconnect between the two.

 

Bill

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, June 08, 2015 7:01 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Bill

 

12 gal/hr for takeoff sounds extremely low. I'm closer to 25. 

 

 I leave the prop in automatic mode all the time. I set the prop to go around rpm on downwind. 2300 / 6500 works well for me and almost eliminates air breaking during short final. I try to carry a small amount of power through the flare but I think that's common with RV's. I had to really work on slowing down before entering the pattern and adjusting the prop to 2300. 

 

Bobby

Sent from my iPad

On Jun 7, 2015, at 11:25 PM, Bill Bradburry <flyrotary@lancaironline.net> wrote:

Charlie,

I am flying a Lancair Legacy Fixed Gear.  I burn 8.5 – 9 gal/hr at cruise and a little over 12 on take off.  I don’t have my fuel flow calibration completed and it could be part of a gallon or so off on the EM-2. I get over 20 mpg at over 185 mph which I still have trouble getting my head around!  In a car going that fast you would be measuring it in gallons/mile!   I really never tried to lean the engine before I put the broadband sensor in the plane so I don’t really know the answer about the egt spread.  I do get a lot higher egt readings than were advertised.  I was expecting temps in the 15-1600s, but they are in the 1700s.

 

Since the rotary is so sensitive to rpm for power output, I don’t know if I would have been happy with it with a fixed prop unless I had more power than I needed.  I have seen two MT props for sale since I bought mine and both were good deals.  I highly recommend the electric prop.  It responds a little slower than a hydraulic prop, but that is only a problem if you slam the throttle.  I guess the other con for the prop is it helps to carry some power to touchdown because if you chop power in the flare, the prop goes flat and acts like a big brake and the plane seems to just stop flying and drop.  I carry power, but I think Mark switches the prop to manual in the pattern and lands it like it was a fixed prop.  I don’t know what Bobby does in this case.

 

Bill

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Sunday, June 07, 2015 7:14 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

 

Hi Bill,

I'm always hungry for 'numbers' like that. Can you refresh my memory on which plane you're flying?

What's your fuel flow during takeoff?

And I'm really interested in your fuel flow at your cruise setting of 6000 rpm full throttle up at 7500-8000 feet. Do you have an EGT in addition to your f/a gauge? If so, what's the egt spread between peak and leaned to your cruise setting of 16-1 f/a ratio (how many degrees lean of peak)?

Having a controllable prop certainly makes it easier to get a full set of performance numbers, doesn't it?

Many thanks,

Charlie

On 6/7/2015 2:59 PM, Bill Bradburry wrote:

Rich,

I am flying the NA Renesis with MT electric prop and wideband O2 sensor.

Take off and initial climb is WOT with 7100 rpm, after about 500 ft AGL, I dial the prop back to 6500 rpm, still WOT. Cruise climb is WOT and 6000-6200 rpm, and cruise is WOT and 5200-5800 rpm. All climbs are at 12.0-12.5 F/A mixture and cruise is 15.8-16.0 F/A mixture.

I never move the throttle off of wide open until I am slowing to enter the pattern for landing. Engine speed is controlled with the prop and power to some extent with the mixture.

I have hopes that after Bobby makes his decision as to whether to go with the turbo or the 20B, he will give me the other one! :>)

Bill

---

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Sunday, June 07, 2015 10:25 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: new operating question

Rich,

My normal, not in a hurry settings.

38" MP / 7000 rpm for takeoff and initial climb with F/A 12.5-12.0. Cruise climb 5800 rpm 30-32" MP F/A 13.5- 12.5. Preferred cruise rpm 4800- 5200 At less than 30" MP and F/A 15.8-16.0. Full throttle. Prop rpm controls engine rpm and super charger bypass controls MP. A turbo charger and automotive waste gate would likely require throttle management during high rpm operations.

Bobby Hughes

Super charged Renesis with electric MT prop.

(New Turbo charger and a 20B on the bench- still haven't made a decision about upgrading the RV10. )

Sent from my iPad

On Jun 7, 2015, at 9:34 AM, ARGOLDMAN <flyrotary@lancaironline.net> wrote:

Greetings genlepeople of the rotary pursuasion,

For those of you using variable pitch (C/S) props, an operating question that has been bugging me. Perhaps the collective wisdom of this group can set my mind at rest.

In piston aircraft engines, the concept of running over squared MP vs RPM has been heavily questioned to the extent that some suggest running at full throttle all the time and controlling the power output via RPM (within reason). The thought is to, I believe, eliminate the induction restriction of the butterfly valve increasing the efficiency.

Now we have a rotor spinning, a gear box gearing and a propeller propelling. Does this concept hold true for the rotaries. What are people doing in terms of setting power after take off (full throttle max RPM).

My enquiring and rotating mind wants to know.

(Unturbocharged Renesis with RD1-c Box)

Thanks

Rich