Radial engine bike by Jesse James

[terbang]

Bloody hell, that's just terrifying! And no doubt after they recognised the pointlessness of that design, the went to work on the prototype BAe 146.

The 146..! Built by the confused to be flown by the perplexed, I flew em for 7 years. Flew the 507 powered Avro RJ a bit later on which was what the 146 should have been, a shame it came too late to save the project. 4 engines is good, 5 APU's is not so good.

[pete376403]

Best Engine Ever - Napier Deltic http://en.wikipedia.org/wiki/Delta_engine
Almost like three Commer TS-3s arranged in a triangle.
Other variants on the opposed piston theme - Junkers Jumo bomber engines - possibly the first diesel powered aircraft

Even better animation of the deltic (3d, rotating) go here http://www.wis.co.uk/justin/deltic-engine.html

[Sully60]

The cam timing on a radial is actually not too bad, once you've figured out how they work. Even seeing the motor off our Wilga in bits, it took me a while.
The cams are actually rings (usually one inlet and one exhaust) which are driven off the crankshaft by an epicyclic gearbox because they rotate much slower than for a conventional layout where the cam runs at half crank speed.
Each ring has a number of lobes, (actually the lobe number is half the number of cylinders minus one), so that e.g. a 9 cylinder radial cam has 4 lobes.
The firing order for the same example is 1,3,5,7,9,2,4,6,8. In effect it fires 5 cylinders on the first crank rotation and the remaing 4 on the second. The firing pulses are evenly spaced cos it actually takes slightly more than one rotation to fire the first 5 and slightly less to fire the last 4.

Each cam lobe moves 1 cylinder per rotation, so for a 9 cylinder engine, the cam runs at 1/9 of crank speed.

Consequently, they are always gear driven and aligning the timing marks is pretty straightforward.

Thanks Bass
I thought they must employ a system like this as 18 camshafts/lobes per bank would be very complicated especially on a 28 cylinder radial.

[Animal]

...4 engines is good, 5 APU's is not so good.

I worked on the 502 (under)powered version for Ansett NZ for a few years - diabolical pieces of apparatus! I've maintained a helluva broad range of aircraft all over the world but that was the only one that seemed to be pre-corroded by the factory before being assembled and sent off to unsuspecting purchasers.

[Bass]

I finally found a legible illustration of a Napier Sabre sleeve valve

Help me here please.
I remember years ago when visiting the Queenstown motor museum, finding a large H configuration motor on display, that had been used to power a tank. I cannot be sure, but I believe it was an aero engine and have this vague idea that it was a Sabre.
Do you know anything about this?

[Bass]

I worked on the 502 (under)powered version for Ansett NZ for a few years - diabolical pieces of apparatus! I've maintained a helluva broad range of aircraft all over the world but that was the only one that seemed to be pre-corroded by the factory before being assembled sent off to unsuspecting purchasers.

Was that the Whimperjet?

[Animal]

Hi Bass, I haven't been to that museum myself, but I'll certainly see what I can find out. The Airforce museum here in Ch'ch has a Sabre and some other excellent exhibits if you're even in this part of the Mainland.

[Animal]

Was that the Whimperjet?

It was indeed! I hated the bloody things. They certainly top my list of the crappiest aircraft I'd ever worked on!

[nudemetalz]

What was so bad about the '146s ?

[Animal]

What was so bad about the '146s ?

The list is long, but I'll point out the most common criticisms of the breed...

They were severely underpowered. The Alison 502 engines in them were an adaptation of a turboshaft helicopter engine, converted by essentially adding a fan on the front of the compressor. Their operational tolerances were very tight, and tweaking them to stay within the parameters of the performance chart was a challenge. It didn't take much of a shift on the performance curve to fail the minimum requirements.

They featured some very old technology, which first appeared in several early British military aircraft such as Buccaneers and Canberras. The pitch control was aided by one such system, which was primitive and unbelievably Heath Robinson in it's design and application. I'll dig out some diagrams which will better explain this because it would take me hours to do so in words alone.

They had a well-deserved reputation for terrible corrosion, and operating them on short hops to sea-level airports (like those in NZ!) accelerated the rate of deterioration. We spent thousands and thousands of man-hours on corrosion management and repairs alone, making them an expensive machine to maintain.

BAe rejected the use of any universal aircraft hardware (such as AN and Mil-Spec), which meant even chuckaway items like screws and bolts had to be purchased from BAe themselves. Having a monopoly on the supply of parts meant they could charge anything they liked - and certainly did! Also, if they were out of stock on a particular part, calling up Boeing, Bombardier, Learjet, Airbus or McDonnell for an AN bolt or washer wasn't a legitimate option. Grounding a 146 while waiting for a handful of proprietory screws wasn't unusual.

The modified chopper engines had no reverse thrust capability, so braking was done through wheel brakes and those huge clam-shell air brakes on the arse. Flying into short strips like Queenstown meant generous applications of braking, so for an aircraft of the 146's size, the consumption of tyres and brake assemblies was right out of proportion. I seemed to be forever changing brakes on the bloody things.

For a 146 pilot's viewpoint, Terbang will have to be approached for his opinion.

I'll have a fossick through my library of course notes and other shit tonight, which will no doubt jog my memory on all the other things I disliked about them. They were fragile, temperamental, finickity machines, and certainly weren't a pleasure to work on.

[nudemetalz]

Fascinating stuff, CADa. Thanks
I always wondered why a jet like that didn't have reversers on it.

They didn't last that long in service (compared to the 732 and 733/734's).

I wonder wehat influenced Air NZ and Qantas to buy them in the first place.
Rock-bottom price ?

[Bass]

Sounds like BAe was a branch of BMC

[nudemetalz]

Sounds like BAe was a branch of BMC

Love it !!!!

[Bass]

Love it !!!!

We aim to please

[Animal]

I wonder wehat influenced Air NZ and Qantas to buy them in the first place.
Rock-bottom price ?

Who would know! A really bad poker hand perhaps?

Ansett NZ originally had three of the oldest 737-200s in the world when they started out as Newmans Air, a rather long time ago. They also had De Havilland Dash 7s. I'm admittedly very uncertain about the airline's corporate origins, but when News Corporation bought Ansett Australia, Ansett NZ was somehow part of the deal. I think because Ansett Australia had been lumbered with 146s, the NZ operation was obliged to share the punishment and a whole lot more were leased and sent over here. Surprisingly, the only significant business elements we shared with our Ansett Australia counterparts was the inventory pool in Melbourne and the branding.

When AirNZ and Qantas were desperately trying to get government / commerce commission support for their Open Skies agreement, it was resoundingly rejected. Around this time, Ansett Australia was in a whole world of shit thanks to Virgin's entry into their domestic market. The Australian government came up with a cunning plan: If AirNZ bought Ansett Australia from Murdoch / News Corporation, the Open Skies deal would be approved. AirNZ bought Ansett Australia and all of it's significant debt, which almost caused AirNZ to collapse. Then the Australians reneged on the deal and opposed the Open Skies idea. As usual, NZ was bent over and... well, you know. Our tax money and Queen Helen bailed AirNZ out, but Ansett Australia was history. A point to note here is that the NZ taxpayer also footed the redundancy bill for the entire Ansett Australia staff.

Ansett NZ was bought from News by a gang of NZ businessmen, and renamed Tasman Pacific Airlines of NZ. A deal was then struck where we would fly under Qantas branding, hence the appearance of 146s and Dash 8s with white kangaroos on their red arse-parts. Only a few months later, Qantas NZ fell over and went into receivership, and since AirNZ was legally the leaseholders of the fleet through their original acquisition, the 146s were suddenly AirNZ's problem. The aircraft were very quickly repainted into AirNZ livery and operated as the Mount Cook fleet.

As the leases expired, the 146s were progressively returned to the leasing company and disappeared from NZ's skies forever. Back to my earlier point, the NZ taxpayer did not foot the redundancy bill for Kiwis who lost their jobs, but Ansett NZ wasn't the National Airline. After Tasman Pacific's few unsold assets were liquidated, the staff got very little of what they were owed. (And yes, I'm still extremely bloody shitty about that!)