Jabiru Gen 4

[skippydiesel]

11 minutes ago, facthunter said:

RPM is not enough . You need a torque figure or a thrust figure as well.   You could be way out. MP might suffice.  Nev

From poor memory (will need to check on next flight) MAP around 22" 

[Kenlsa]

Just for giggles….my Gen1 SP500 uses 11.7lt/hr.   100 true @ 2800rpm with 44” pitch wooden prop. 
 

Just sold it this week after 18 years. Why you may ask? So I can pay for the rebuild of my Lycoming:  And can now look forward to 24lt @ 90 kts. Hmmmm !
Ken

[skippydiesel]

RFguy, 

 

"The discussion is aircraft invariant"  

 

This phrase intrigued me - what is the meaning of ".....invariant"??

 

Looked it up - means  not changing. So your statement could be read as  - The discussion is aircraft not changing.  Tad cryptic don't you think?

 

Being short of what few brain cells I was born with, I still do not understand. Please explain?

[Blueadventures]

Performance of Rotax 912 in Sonex is inferior to Jab 3300 engine after comparison testing by the manufacturer.  Therefore Jabiru 3300 is King in both climb rate and cruise.

[justinjsinclair]

7 hours ago, Kenlsa said:

Just for giggles….my Gen1 SP500 uses 11.7lt/hr.   100 true @ 2800rpm with 44” pitch wooden prop. 
 

Just sold it this week after 18 years. Why you may ask? So I can pay for the rebuild of my Lycoming:  And can now look forward to 24lt @ 90 kts. Hmmmm !
Ken

But it’s a colt ❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️, will it be losing the front wheely thingy ?

[skippydiesel]

50 minutes ago, Blueadventures said:

Performance of Rotax 912 in Sonex is inferior to Jab 3300 engine after comparison testing by the manufacturer.  Therefore Jabiru 3300 is King in both climb rate and cruise.

Very nice Blue,

 

I would point out that:

 

Sonex have only very recently "recognised" Rotax 9 engines for installation in their aircraft, so I wonder how good their data is?

To the best of my knowledge Sonex do not have or ever had, a Rotax powered airframe, with which to arrive at the above figures.

Sonex are so slow to adopt Rotax, that they are only now coming up with a suitable engine mount for future kits

 

My Sonex Legacy/Rotax 912ULS will easily achieve (Max load):

• 1500 fpm in Climb Out,  80-100 knots, - I am still working on best climb speed.
• 130 + Knot True (150 mph) at 3000 ft, 5200 rpm, @ 15L/hr
• 147 knots indicated 150 + knots (173 mph) at 5450 rpm, 5500 ft, still working on the fuel but believe its 18-19L/hr

If you are wondering about the accuracy of the above air speeds,- the pitot/gauge system has been independently tested and a range of errors noted:

 

Indicated/Corrected Air Speeds in Knots

40/48.5, 60/66, 100/103, 120/123

140/142, 150/152, 165/166

 

PS -

• For me, speed itself, is only an indicator of airframe efficiency, when powered by the same/competing engines. Sonex recognise engines to 130 hp however it must be obvious to all, that while the speed may be greater, with such an engine, so is the fuel consumed to arrive at that speed. I want to travel in my Sonex , so fuel consumed per hour for a given speed will determine my power setting for near best range - I think my Rotax will do this for me.
• Do you think the tendency of US small aircraft manufacturers, to express their aircraft performance, in mph might be because it always looks better than in Knots???😈

Edited April 26 by skippydiesel

[Thruster88]

53 minutes ago, Blueadventures said:

Performance of Rotax 912 in Sonex is inferior to Jab 3300 engine after comparison testing by the manufacturer.  Therefore Jabiru 3300 is King in both climb rate and cruise.

These numbers seem a tad rounded and they do not make sense re the turbo 100hp v non turbo 100hp in respect to altitude performance. They are not credible.  

[BrendAn]

5 minutes ago, skippydiesel said:

Very nice Blue,

 

I would point out that:

 

Sonex have only very recently "recognised" Rotax 9 engines for installation in their aircraft, so I wonder how good their data is?

To the best of my knowledge Sonex do not have or ever had, a Rotax powered airframe, with which to arrive at the above figures.

Sonex are so slow to adopt Rotax, that they are only now coming up with a suitable engine mount for future kits

 

My Sonex Legacy/Rotax 912ULS will easily achieve (Max load):

• 1500 fpm in Climb Out,  80-100 knots, - I am still working on best climb speed.
• 130 + Knot True (150 mph) at 3000 ft, 5200 rpm, @ 15L/hr
• 147 knots indicated 150 + knots (173 mph) at 5450 rpm, 5500 ft, still working on the fuel but believe its 18-19L/hr

If you are wondering about the accuracy of the above air speeds,- the pitot/gauge system has been independently tested and a range of errors noted:

 

Indicated/Corrected Air Speeds in Knots

40/48.5, 60/66, 100/103, 120/123

140/142, 150/152, 165/166

 

PS - Do you think the tendency of US small aircraft manufacturers, to express their aircraft performance, in mph might be because it always looks better than in Knots???😈

A friend of mine has been flying a 912 powered sonex he built for a few years now . I think that is the second Rotax one he has built.

[skippydiesel]

1 minute ago, BrendAn said:

A friend of mine has been flying a 912 powered sonex he built for a few years now . I think that is the second Rotax one he has built.

My Sonex started its life in Gippsland - seems to be a hotbed of Sonex/Rotax.

[BrendAn]

7 minutes ago, skippydiesel said:

My Sonex started its life in Gippsland - seems to be a hotbed of Sonex/Rotax.

Who built it. 

Edited April 26 by BrendAn

[Blueadventures]

1 hour ago, skippydiesel said:

Very nice Blue,

 

I would point out that:

 

Sonex have only very recently "recognised" Rotax 9 engines for installation in their aircraft, so I wonder how good their data is?

To the best of my knowledge Sonex do not have or ever had, a Rotax powered airframe, with which to arrive at the above figures.

Sonex are so slow to adopt Rotax, that they are only now coming up with a suitable engine mount for future kits

 

My Sonex Legacy/Rotax 912ULS will easily achieve (Max load):

• 1500 fpm in Climb Out,  80-100 knots, - I am still working on best climb speed.
• 130 + Knot True (150 mph) at 3000 ft, 5200 rpm, @ 15L/hr
• 147 knots indicated 150 + knots (173 mph) at 5450 rpm, 5500 ft, still working on the fuel but believe its 18-19L/hr

If you are wondering about the accuracy of the above air speeds,- the pitot/gauge system has been independently tested and a range of errors noted:

 

Indicated/Corrected Air Speeds in Knots

40/48.5, 60/66, 100/103, 120/123

140/142, 150/152, 165/166

 

PS -

• For me, speed itself, is only an indicator of airframe efficiency, when powered by the same/competing engines. Sonex recognise engines to 130 hp however it must be obvious to all, that while the speed may be greater, with such an engine, so is the fuel consumed to arrive at that speed. I want to travel in my Sonex , so fuel consumed per hour for a given speed will determine my power setting for near best range - I think my Rotax will do this for me.
• Do you think the tendency of US small aircraft manufacturers, to express their aircraft performance, in mph might be because it always looks better than in Knots???😈

All the data shows is that the Jab is the engine for performance and a Rotax 912 will never catch the Jab 3300. That's all the manufactures statement is saying.  As such the nice Jab 3300 is the better engine for performance.  Therefore Robins record could be bettered with a Jab 3300 in his aircraft or similar tweaked similar airframe. .

[BrendAn]

1 hour ago, BrendAn said:

A friend of mine has been flying a 912 powered sonex he built for a few years now . I think that is the second Rotax one he has built.

I have mentioned this plane before, 

He made his own EFI and retained the carbys. They are dry but if the EFI fails he pulls a cable and sends fuel to the carbs . He does not like carbys on top of an engine. I have not read of fires from flooded carbs though I guess it is possible.

[turboplanner]

23 minutes ago, BrendAn said:

I have mentioned this plane before, 

He made his own EFI and retained the carbys. They are dry but if the EFI fails he pulls a cable and sends fuel to the carbs . He does not like carbys on top of an engine. I have not read of fires from flooded carbs though I guess it is possible.

Have a look at a V8 some time.

[BrendAn]

1 hour ago, turboplanner said:

Have a look at a V8 some time.

I should have said 912 fires which is the engine we are talking about, not V8 cars .

[Area-51]

The only reason the Gen4 3300 appears a better performer is the fact the claimed 120hp 180Nm torque happens at 3500rpm... So let's equalise the field to a realistic constant 2400rpm at the propeller flange 😃

 

The Gen4 now delivers 92.43hp and 202Nm torque...

 

The 912UL will deliver 87.0hp and 230Nm torque.

 

The 914 will deliver 106hp and 315Nm torque, without intercooler.

 

The 912is will deliver 101.1hp and 306Nm torque

 

Now lets go to 2700rpm constant at the propeller flange 😀

 

The Gen4 will deliver 104.4hp and 203.2Nm of torque.

 

Non of the rotax 9XX powertrains can reach this RPM ☹️

Its now a good time for post drift into commodore V's falcon debate with token valiant mention

 

🤷🏼‍♂️🤷‍♀️

 

[turboplanner]

6 hours ago, BrendAn said:

I should have said 912 fires which is the engine we are talking about, not V8 cars .

They all have carbies not only on top of the engine but sitting in the V.

But they are V8 cars of course, so we need to translate to 912.

If you want to put a carby on top of a 912 you just need a flame-proof drain tube exiting below the engine and outside the cowl.

What's a lot more important is to ensure air intake filters are not flammable. A good backfire into the air filters loved by the aftermarket are good for a 2 metre high flame.

[jackc]

In my opinion, Aviators should have some kind of light weight fire suppression system under engine cowl, IF available. And being a safety item, MTOW increased to cover the extra weight same as a BRS

[Thruster88]

The cessna 414 I have been working on recently has such a system. A bottle about 15cm and a hose running to the front, electric valve to release the goods. Could be retrofitted to an experimental.  

[skippydiesel]

13 hours ago, BrendAn said:

Who built it. 

Sorry BrendAn - I would need the original builders permission to reveal his name on a public Forum.

[BrendAn]

4 minutes ago, skippydiesel said:

Sorry BrendAn - I would need the original builders permission to reveal his name on a public Forum.

Good call. I didn't think of that.

[skippydiesel]

12 hours ago, Blueadventures said:

All the data shows is that the Jab is the engine for performance and a Rotax 912 will never catch the Jab 3300. That's all the manufactures statement is saying.  As such the nice Jab 3300 is the better engine for performance.  Therefore Robins record could be bettered with a Jab 3300 in his aircraft or similar tweaked similar airframe. .

My reading of the Sonex chart:

The engines for their aircraft are in their prefered order. ie the data is skewed in that direction

[BrendAn]

4 hours ago, turboplanner said:

They all have carbies not only on top of the engine but sitting in the V.

But they are V8 cars of course, so we need to translate to 912.

If you want to put a carby on top of a 912 you just need a flame-proof drain tube exiting below the engine and outside the cowl.

What's a lot more important is to ensure air intake filters are not flammable. A good backfire into the air filters loved by the aftermarket are good for a 2 metre high flame.

Please stick to the topic.912 carbs are on top . That's how they are made . Forget about cars and what you can and can't do. I know other people that have expressed concern about top mounted carbs on an aircraft too. It's not my opinion.

Have a look at traditional aero engines. The carby is always underneath, same with jabiru.

[Blueadventures]

29 minutes ago, skippydiesel said:

My reading of the Sonex chart:

The engines for their aircraft are in their prefered order. ie the data is skewed in that direction

Don’t see that; looks historical with Aerovee first, then Jab being similar and air cooled also, then the Rotax as some want to fit those and lastly the newer UL range that will fit the Jab mount. The aircraft first designed for air cooled engines and the Jab 3300 is undoubtably the best performer being 25% better climb rate as one example.

[RFguy]

WRT sonex - it's unsurprising  that a  the 120 hp jab goes faster  the 100 hp 912ULS rotax .

why ? because  at any altitude, it has more power.  simple......

and power = rpm x torque so forget about talkign about torque. 

I dont 't know why that is in any contention. 

 

ideally, thrust would be presented. that's the final say...

 

[kgwilson]

11 hours ago, Area-51 said:

The only reason the Gen4 3300 appears a better performer is the fact the claimed 120hp 180Nm torque happens at 3500rpm... So let's equalise the field to a realistic constant 2400rpm at the propeller flange 😃

 

 

The claimed power of the 3300A engine is 90kW or 120HP at 3300 rpm not 3500 rpm. 3300 rpm is the maximum rated power setting for continuous operation. Some individual engines have produced 128 - 130 HP on a dyno.

 

I have set the Bolly BOS 5 prop pitch on my Gen 3 3300A engine to read 3300rpm at full power S&L at cruising altitude. This has reduced the full power climb to about 1200 fpm but that is more than adequate. At 5000 feet in my home built Sierra I have IAS of around 120 knots at full power which is a TAS of 132 knots.