Jabiru Taildragger

[Round Engines]

Hi Flyers,

 

Does anyone have any first hand experience or knowledge for converting a 2 seat Jabiru from tri-gear to a taildragger.

 

Thanks in advance,

 

RE

 

 

[Soleair]

Great idea. Please publish progress & pix if you go for it.

 

 

[billwoodmason]

Hi Flyers,Does anyone have any first hand experience or knowledge for converting a 2 seat Jabiru from tri-gear to a taildragger.

 

Thanks in advance,

 

RE

There are a few around. A phone call to Jabiru would put you in touch with some builders who have gone this route.

 

 

[408059]

RE

 

I recollect that Paul Middleton, former CEO of RAA, built a Jabiru tail dragger and afterwards converted it to a tri-gear. Wrong way around compared to what you wish to do but he may be able to help if you can track him down.

 

From memory there was a kitchen table discussion some years ago, between club instructors, and the view was not all that positive towards the tail dragger version, especially in the context of a trainer. The discussion focused on rudder authority and flaps blanketing the tail plane. The upshot was that the tail dragger version of the Jabiru is a very different beast to the tri-gear in terms of manners.

 

Steve

 

 

[red750]

Seen at Avalon this year:

 

 

 

[Deskpilot]

I have to accept it being right but those mail wheels always seem too far back to me. Not a beauty in my eyes.

 

 

[Old Koreelah]

I agree DP, even though I've always liked the idea of building a STOL version of a J-170.

 

 

[billwoodmason]

There used to be one hangared at Lethbridge Airpark, it may well be the one in the Avalon photo above. The Grey Mongrel refers to the owner. A search of Raa registrations would find him.

 

 

[peterg]

Hi Flyers,Does anyone have any first hand experience or knowledge for converting a 2 seat Jabiru from tri-gear to a taildragger.

 

Thanks in advance,

 

RE

Hello

 

If you PM me I can put you in touch with the owner of the "Mongrel" which is based at Lethbridge and there was another at West Sale which has recently been sold - owner was/is a L2 and I can put you in touch with him as well.

 

Regards

 

 

[facthunter]

The wheels are not too far back. Having them forward makes them extremely likely to ground loop. As that plane is sitting, the wheels are forward of the leading edge.

 

Middo's plane was rebuilt by Jabiru but only IF it went back to tri gear. Nev

 

 

[pylon500]

I've had a little to do with this J230 version over the years, still only flies like a Jabiru (take that whichever way you like), but fairly good utility.

 

Bit of a beast with a Lyco 233 up front, and the U/C on this one is possibly just a little far forward, which keeps you on your toes..

 

 

 

[Bruce Tuncks]

Does anybody know what sort of speed increase you could expect from the mod to tail-dragger?

 

Once I discussed fairing the nose-leg to reduce drag, but I was convinced that adding side-area so far forward would be destabilizing.

 

 

[facthunter]

The tail dragger has to be cleaner, all other things being equal. A Piper Colt /Pacer comparo might give indicators Texas Taildragger/152 also Try before you buy is appropriate with these mods. Skyfox /Gazelle also for handling. Nev

 

 

[Yenn]

Another factor that should make a taildragger conversion faster than a tricycle configuration is the rearward movement of the C of G. Less downthrust required from the elevator.

 

 

[Oscar]

With all due respect to the work that must have been put in to making that J230 conversion, I wonder about the engineering.

 

The (relatively few) Jabs. that have been 'factory-equipment' changed to tail-dragger, utilised main gear that attached to the standard attachment points, just with a forward rake on the 'glass legs. The Jab. design was intended for tricycle gear, and the major bulkhead behind the occupants shoulders takes the form of a 'hoop' that transfers the rear spar load, the lift strut load, and the main gear load in a very effective structural design, which incorporates the occupant seat structure for added stiffness. Then, you have the front carry-through web and the 'A-pillars - very hefty 'glass members - down to the firewall, off which mounts the engine and the noseleg, and a central spine structure that completes the occupant safety capsule.

 

It is a complex design, and it has been proven many, many times to provide one of the best occupant safety capsules for this class of aircraft. The U/C attachment on that 230, probably cannot replicate the force conditions of the original design. If it does, then I take my hat off to the builder.

 

U/C design is a major part of occupant safety. If you watch the 'drop test' videos that Jabiru has on its web-site, you will see the extreme forces that are resisted, with the reaction to those forces being taken out by the deflection of the legs. What you DON'T see, is the cumulative effect of leg-spring and tyre deflection, but it's all been calculated into the test regime.

 

IF any component of the U/C fails prematurely and drops the fuselage onto the ground with excessive force, the likely result is at best, paraplegia. I guess it's a personal decision as to whether you want to get better performance, or be able to walk if a landing goes pear-shaped. Just personally, I'd be happier to be able to get out and kick the damn thing for not having gotten me to the accident sooner..

 

 

[pylon500]

All quite valid, and while I don't know who did the engineering for the mod (we did have an aero-engineer building a Wheeler Express here), the gear mounting was proven after an EFTO with the aircraft ending up in a deep ditch at the end of the runway.

 

I became involved in flight testing after the rebuild from this incident, and a different motor.

 

Although the gear leg snapped, there was only minor damage to the mounting structure, if any (I cant remember as I wasn't really involved with the project at that time.

 

the aircraft was built from an early J200 kit.

 

 

 

 

 

 

[Oscar]

Fair enough - hard test, can't argue with the result.

 

 

[Old Koreelah]

Much as I love taildraggers, Oscar has a point about the role of the undercarriage in protecting your backside from violently meeting the ground (and in an emergency landing, that could include rocks, stumps and other nasties hidden in the grass). The Jab, like most little planes, has precious little between your posterior and the bottom of the aircraft. I've had a gear leg fail when landing a Jab and it was a non-event because there was a nose wheel to help the other mainwheel keep the prop and my butte off the ground.

 

 

[Bruce Tuncks]

Glad all was ok Old K.

 

What caused the main leg failure? We have had a bolt let go but that was wheeling it out the hangar, and now those bolts have been upsized.

 

 

[facthunter]

Nosewheels are weak relatively. When they are gone you have no hope whatever of stopping the front of the plane digging in, as the mains are so far back, then you usually invert. Nev

 

 

[red750]

Nev, the plane in the photos is a taildragger - see tailwheel in last photo.

 

 

[Old Koreelah]

Glad all was ok Old K.What caused the main leg failure? We have had a bolt let go but that was wheeling it out the hangar, and now those bolts have been upsized.

Bruce it was on an old school aircraft that had done heaps of work. The inner bolt of the RH u/c leg broke as I touched down on a bumpy patch of grass. The other two bolts held, but as the leg folded up the right wingtip hit the ground and slid a few metres. The left main and nose wheel described a nice arc to the right and we came to a gently stop at a bit of an angle. No drama.

After a long walk to get some tools and and new bolt I put the seat cushion and the wingtip on my head while the bolt was replaced. About ten minutes work. Superficial damage to the wingtip gelcoat only.

 

Just love fibreglass aeroplanes, and the Jab in particular!

 

 

[Soleair]

Nev, the plane in the photos is a taildragger - see tailwheel in last photo.

A taildragger does not have a tailwheel, just a skid. Hence the name.

 

A.Pedant

 

 

[red750]

It doesn't have a nosewheel either.

 

 

[frank marriott]

Bruce it was on an old school aircraft that had done heaps of work. The inner bolt of the RH u/c leg broke as I touched down on a bumpy patch of grass. The other two bolts held, but as the leg folded up the right wingtip hit the ground and slid a few metres. The left main and nose wheel described a nice arc to the right and we came to a gently stop at a bit of an angle. No drama.After a long walk to get some tools and and new bolt I put the seat cushion and the wingtip on my head while the bolt was replaced. About ten minutes work. Superficial damage to the wingtip gelcoat only.

Just love fibreglass aeroplanes, and the Jab in particular!

Was this before or after the 500hr life SB?