turbines for jabirus

[g-lock69]

Hi there guys!!

Apparently some guy fitted a 737 apu to a jabiru!! It had vertical climb capability, and a 25000 ft ceiling. Due to the fact it cruises at such a height it can maintain 150kt indicated which equates to a 250 kt TAS (Ididnt check it on my wizz wheel). So considering it can fly at the height of a jetstream (which for the definition, has to be at least 60kts in magnitude, u can get a 300kt ground speed out of it. Because it has beta mode if one was game, u can descend vertically. The hurdle will be getting it IFR certified.

[BlueRobin]

Now consider the fuel tank capacity in the Jab and the fuel burn rate. You'd barely get to the end of the runway. ;)

Someone did something similar in a Luscombe but the range is pap.

[bar shaker]

It sounds like an urban myth to me.

The APU would outweigh the Jab body and where would you mount it, let alone the fuel?

[jtr]

As one happy to admit I know little of the a/c.. how about a Walter engine, probably weighs much the same as whats in there now, and pumps out 5 times the noise. Yeh range goes out the window, but I doubt you buy a Jab for the range.

[Genghis the Engineer]

Apparently some guy fitted a 737 apu to a jabiru!!
Could be done, but you'd need one hell of a reduction gear - you'd also struggle to get a noise certificate on it in the UK or Europe.


It had vertical climb capability, and a 25000 ft ceiling.
Sounds fairly realistic.


Due to the fact it cruises at such a height it can maintain 150kt indicated which equates to a 250 kt TAS (Ididnt check it on my wizz wheel).
Vne on a Jabiru is 116 kn IAS, so assuming that it's airspeed indication errors are roughly linear, that's about 30% above Vne, and in all likelihood beyond the design structural limits.

Also, 150kn CAS at FL250/ISA equates to 202kn TAS - not even close.


So considering it can fly at the height of a jetstream (which for the definition, has to be at least 60kts in magnitude, u can get a 300kt ground speed out of it.
Well, disregarding for a moment that there is almost certainly not enough spare mass in a Jabiru to fit the oxygen system you'd need....


Because it has beta mode if one was game, u can descend vertically. The hurdle will be getting it IFR certified.
You'd also have to try and get the duplicate instrumentation, transponder, VOR/ADF/etc - maybe is somebody would allow it as a single seater only, but certainly not 2-up.

Okay, maybe the 4-seat Jab 2-up !

G

[nouseforaname]

If you put a turbine engine into BETA mode in flight be prepared for a very quick ending!

[BEagle]

Perhaps you're thinking of the astonishing Oracle-sponsored Turbo Raven which had a 750 shp PT6 engine and could climb to 10000 ft in little more than a minute. It later climbed to around 20000ft in just over 3 minutes.... It had a thrust to weight ratio of about 1.5:1, could climb vertically and then hover in the climb. It could also use beta reverse thrust in the air and its airshow routine used to include a steep descent using this feature...

Sadly it was lost at an airshow in 1999; fortunately the pilot, Wayne Handley, survived. He said that the engine didn't spool up when he took it out of reverse pitch to fly out of the steep descent manouevre. However, post crash strip down showed that the prop had been in the normal forward flight pitch range and that the engine had been in the mid to high power range at impact. The NTSB concluded that he hadn't maintained sufficient airspeed and had simply stalled......

See http://www.ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19979&ntsbno=LAX00LA003&akey=1

[Christo]

I don't understand this last post. Granted I have zero time on turbines but I see the porters do BETA approaches all the time with no ill effects!!

[LowNSlow]

Don't forget the Hot Wot, a Currie Wot single seat biplane fitted with a Rover 180 shp two stage turbine (ex V-bomber APU??). The same engine was also fitted into an Auster, looked neat.

[stiknruda]

I was in the States in '99 doing some flight training at Scottsdale with Budd Davisson. He had a prior engagement one morning but took me along. We met with Wayne Handley and Tim Webber at a field north of Pheonix.

The plan was that Budd would take some air 2 air of Wayne flying the Raven. It was a most impressive aeroplane (airplane!) and the finish was superb. Wayne had just broken a bunch of records, including the inverted spin record, I can not recall exactly how many it was but it was something like 72 rotations from 10,000ft. Three is plenty for me!

The photo-ship was a SenecaII with Tim and his "assistant" in the front. Budd and I stripped out the rear seats, took off the left cargo door and loaded ourselves and Budd's camera gear in the back.

We joined up a few miles north of the field and Budd called Wayne into various positions, erect and inverted and all I did was pass Budd various lenses and stop him falling out the door!

The pix were later printed in either Sport Aviation or Sport Aerobatics and the shots were superb.

We landed, pushed the aeroplanes away and were just about to start on the beer.... Wayne and I were chatting about the aeroplane, safely tucked in the hangar when I mentioned Beta.

Son, "Gimme a hand to get this baby out and I'll show you something."

We pushed the Raven out, Wayne jumped onto the wing and said, "Stik, this is what I call a vertical pattern" (circuit in UK/English).

He lined up on the taxiway right in front of us, brakes on, conditioning lever forward and the tail rose; as the PT6 finished spooling he released the brakes, rolled I guess 25 metres and yanked the stick back. The aircraft rotated to the vertical and climbed like the proverbial homesick angel. He called out "1, 000 feet", within seconds and pulled again so that he was inverted and tracking downwind along the along the taxiway at circuit height. After about 150 metres, he pulled again to the vertical downline, popped her into Beta and she slowly descended. It was almost cartoon-like, the propeller was pushing the aircraft backwards.

I kid you not, he was at 30' when he rotated/flared and immediately put the tyres on the taxiway. He ended up taxiing back to the hangar door with the tail up.

Now - he didn't have to do any of that. He wasn't showing off - he chose to show me exactly what his airplane was capable of. A thoroughly decent man and a very good mentor (one of his ex-studes is a US top competitor, display pilot for Red Baron and a mate of mine.) His accident was terribly tragic but he is up and flying again and has been for some time now. One of those aviation days that I'll always remember. I have some photos somewhere to look at when I'm an old man.



Stik