2 engine Jabiru

[Bruce Tuncks]

I guess this aircraft is flying ok in South Africa. Would it be illegal in Australia?

 

Is it possible that the much smaller CASA equivalent in South Africa is actually an advantage for them to pursue advances without the dead hand of bureaucracy holding them back?

 

 

[turboplanner]

I guess this aircraft is flying ok in South Africa. Would it be illegal in Australia?

 

Is it possible that the much smaller CASA equivalent in South Africa is actually an advantage for them to pursue advances without the dead hand of bureaucracy holding them back?

 

There is nothing to stop you joining SAA and designing and building one from Jabiru parts like the South Africans.

 

There's no dead hand holding people back in Australia, with many very interesting approved aircraft flying around.

 

 

[Tasmag]

Jamie at jabiru is flying a 430 

 

twin, has been for a while.

 

 

[red750]

Someone stated - redefining Ugly. With an orange nose and engines it is.

 

 

 

[Deskpilot]

Simple answer is, of course it would......but not under RAA certification.

 

 

[440032]

There is a low winged Jabiru 230 being built somewhere, Victoria I think.... with some fancy auto engine conversion.

 

 

[Bruce Tuncks]

Thanks guys, that's all good news.  Maybe I have a too-negative attitude towards  CASA.

 

There is a sailplane manufacturer in South Africa ( Jonkers ) which make top-class sailplanes, as good as the Germans, and for years I wondered if they operate over there under an easier regulatory system.  Their home market is small and they are a long way from supplies, so how come those south africans are doing so well?

 

 

[turboplanner]

Thanks guys, that's all good news.  Maybe I have a too-negative attitude towards  CASA.

 

There is a sailplane manufacturer in South Africa ( Jonkers ) which make top-class sailplanes, as good as the Germans, and for years I wondered if they operate over there under an easier regulatory system.  Their home market is small and they are a long way from supplies, so how come those south africans are doing so well?

 

If you go back to AUF history we probably did better, but we lost some of our most talented designers.

 

They have had their losses too, but are great innovators like us and NZ.

 

 

[Jaba-who]

No one is making them to sell. Not here in Oz or in South Africa. I’ve been keeping an eye on the happenings because I’m pretty keen to get one when they become available. 

 

Jabiru In South Africa have the most experience and still trying to sort out issues with vibrations. 

 

Stiffy has told me to hang in there for a while yet. 

 

As stated there is nothing stopping anyone with a amateur build VH 230 or 430 pulling it apart and making a twin now but  they would be on their own - Jabiru wouldn’t back them up and it would require a AP to approve the new special Cof A and no AP would be that silly while Jabiru themselves say no. 

 

 

[Thruster88]

For not much more than the price of two engines and mods plus the ugly factor one could fit a 915. Should TAS about 150knots? or better at 10,000. Then you would have something. ?

 

 

[Jaba-who]

But still only one engine. The whole idea is the have two engines. 

 

 

[Yenn]

Two engines and low wing, could you really call it a Jabiru? I doubt that Rod would take any responsibility for it.

 

 

[Thruster88]

But still only one engine. The whole idea is the have two engines. 

 

The second engine only takes you to the crash site in low performance twins.

 

 

[Jaba-who]

The second engine only takes you to the crash site in low performance twins.

 

I’m told the twin jab can climb on one engine at max weight at sea level and climb on one engine (at below max weight but I forget what they weight was) to 8000 ft.

 

Also has docile asymmetrical characteristics because the engines are so close to the centreline. 

 

 

[Thruster88]

I’m told the twin jab can climb on one engine at max weight at sea level and climb on one engine (at below max weight but I forget what they weight was) to 8000 ft.

 

Also has docile asymmetrical characteristics because the engines are so close to the centreline. 

 

The close spacing of the engines would help but it won't be fool proof, relative to the size and length it is not much different to say a piper Seminole. Low performance twins like the Seminole can just maintain about 8000 on one engine. With its 360 total horsepower  and retractable uc it is way slower than a Cirrus with 310 hp. Why reinvent the wheel.   915 in a jab 230 yes it would be a mini cirrus 

 

 

[Jaba-who]

The close spacing of the engines would help but it won't be fool proof, relative to the size and length it is not much different to say a piper Seminole. Low performance twins like the Seminole can just maintain about 8000 on one engine. With its 360 total horsepower  and retractable uc it is way slower than a Cirrus with 310 hp. Why reinvent the wheel.   915 in a jab 230 yes it would be a mini cirrus 

 

Mmm. Seminole is not really anything like a twin jab.  But to go with your example. 

 

I would say the reason to reinvent a wheel if your original wheel is a Seminole is the new wheel is:

 

half the weight

 

2m shorter and 2 m narrower

 

About 1/4 the cost new and probably 1/10 to convert an existing owned 430/230

 

I can take the 430/230 that’s in my hangar and turn it into the twin myself. ( ok -once it becomes available) 

 

Can take off and land in half the distance.  

 

Has less payload but as it is I rarely fly with more than two people on board. That’s all I need.  

 

Use it for a really cheap twin endorsement

 

Why it over a cirrus?

 

all the above again but some numbers vary a bit for the cirrus 

 

Has two engines rather than an engine and a parachute ( though I agree there’s times a chute would be preferable. )

 

but its horses for courses. But to say something exists therefore don’t invent something different is a bit self defeating. 

 

 

[coinz]

How do they deal with the increased VNE?

 

 

[Thruster88]

Mmm. Seminole is not really anything like a twin jab.  But to go with your example. 

 

I was only comparing the jab to Seminole in terms of geometry in an engine out situation.

 

Low performance twins only exist to train pilots.

 

The cruise performance gain of the Seminole's 2x180hp  engines over the aircraft it was developed from the Arrow 180hp is only about 30 knots for all that extra cost. The Seminole's single engine ceiling is only 4000ft and that's with retract and feathering props, I just think the twin jab would be a total dog on one engine. Don't forget that you are going from  120hp to only 80hp per side

 

The twin jab first flew in 2013?  and only a few video's none showing a stopped prop tells me somthing, sorry to be negative but that's how I see it.

 

 

[Methusala]

There is a twin Jabiru engined Zenith home built. Saw it at Wedderburn earlier this year. Two seats and did not inspire me too much.

 

 

[Jaba-who]

I was only comparing the jab to Seminole in terms of geometry in an engine out situation.

 

Low performance twins only exist to train pilots.

 

The cruise performance gain of the Seminole's 2x180hp  engines over the aircraft it was developed from the Arrow 180hp is only about 30 knots for all that extra cost. The Seminole's single engine ceiling is only 4000ft and that's with retract and feathering props, I just think the twin jab would be a total dog on one engine. Don't forget that you are going from  120hp to only 80hp per side

 

The twin jab first flew in 2013?  and only a few video's none showing a stopped prop tells me somthing, sorry to be negative but that's how I see it.

 

I can’t say what it actually flies like as I’ve only seen it static in the jab factory. But Stiffy and Jamie told me it has significant positive flight characteristics on one engine ( figures previously given were what they told me.) and there have been a couple of flying journal articles by independent authors about the South African one and they reflected similar positive characteristics. 

 

Can’t say anything about a Seminole characteristics but I’d have to say that given it is nothing at all like a twin jab ( except it flies and has 2 engines) that the comparison is probably not valid. 

 

 

[Jaba-who]

How do they deal with the increased VNE?

 

Can’t remember. But empirically speaking VNE is airframe stress related so I suspect it just remains the same. 

 

 

[kasper]

For not much more than the price of two engines and mods plus the ugly factor one could fit a 915. Should TAS about 150knots? or better at 10,000. Then you would have something. ?

 

Putting aside the desire for twin engine vs single Whats the deal with wanting a 915?

 

Around 87kg installed (ratiators and fluids) for 135hp continuous vs 84kg installed for a 3300 Jabiru at 120hp ... with 

 

Yes you get 15hp more continueous (20 entra at takeoff) but without increase in VNE those horses are only useful for climb but you are paying $$$$ more for a very complex rotax engine to do that ...

 

K.I.S.S. and I'd go for a 6 pot Jabiru engine if single if pushed.

 

Im not being pushed ... I am still doing my best to wear out a 'simple' 80hp R912 and an even sinpler two stroke R447 ?

 

 

[Thruster88]

Putting aside the desire for twin engine vs single Whats the deal with wanting a 915?

 

Around 87kg installed (ratiators and fluids) for 135hp continuous vs 84kg installed for a 3300 Jabiru at 120hp ...  

 

Rated power to 15,000ft so the 120knots indicated at sea level becomes about 144 TAS at 10,000. I am not saying its a good idea just a better idea than the twin

 

 

[coinz]

Can’t remember. But empirically speaking VNE is airframe stress related so I suspect it just remains the same. 

 

Speed quoted  at 150 kts would then be 10 kts into red zone if no airframe changes,that's all i was thinking.

 

 

[Downunder]

I liked the 915.....until I saw the fuel consumption figures.

 

In a nutshell...something like a 50% gain in power for a 100% gain in fuel usage....

 

Reports of 40lph flat out....and 30 something in cruise.

 

I don't consider 40 lph for 140hp too flattering...

 

It baffles me how such a high tech engine can have such poor fuel consumption compared to the non-boosted 912is...