Shackleton tri-cycle undercarriage
 

I saw this picture the other day of a tri-cycle undercarriage Shackleton, and was struck by the apparent massive distance between the main wheels and the tail. I wonder why they changed from the tail dragger configuration, and if that caused any major issues?

http://www.ukserials.com/images/ukimages/wr981.jpg

Also, what did that Mini on the right hand side of the picture have balanced on top of it?

Also, why didn't Mr Philip L Jackson manage to zoom in a bit better on the woman near the G spot?

I should think the radome sticking out beneath the rear fuselage is your answer. As to handling - no idea but no doubt someone with shacklebomber time will pop up here soon.

The mini looks like an ice cream van - a very small one!

Shackleton tri-cycle undercarriage
 

Looks like an ice cream van

The answer to that one will have something to do with the sort of people who take pictures of aircraft!

S-D

Reckon because the MR radar hung so low on those frames, the tail wheel wouldn't be able to survive landings as it would need to be 10' long...

Not much weight down the back, all the kit is near the front so I doubt it made handling difficult at all...

Surely that dustbin radome is retractable for T/O & landing?

What I could never understand about the trike Shacks was if the a/c was normally a taildragger, why didn't the trike ones try and sit on their erses all the time? Especially if a few blokes wandered aft.

Love to know how they did that- and I hope it wasn't just by adding lead.

The mini might be a burger van not an ice cream van.

It was supposed to retract, but I witnessed one disintegrate at Luqa in 1959.

The radome had failed to retract, the crew did a spanner job and removed the scanner et al, and then landed. The radome was the first part of the a/c to touch the runway. It disappeared in the preverbal puff of smoke.

Shackleton
 

After some time on the ground the scanner would droop as in this photo. As soon as the hydraulics powered up the radome would fully retract. Thus no problem on the MK2 taildragger for landing.

Saw one at Teesside airshow early 70's and its an ice cream mini.

The late Chris Ashworth's superb tome on the Shackleton, the long out-of-print Avro's Maritime Heavyweight, is very vague on the reasons for the switch to a tricycle undercarriage, though it does go into detail about the many differences between the MR.2 and MR.3, describing it as structurally similar, but radically different. The inference is that it was part of the general redesign; the bomb bay was shortened to allow room for both the nosewheel and a new ventral hatch, while the new main wheels were positioned at the rear of the undercarriage well and retracted forward. Even allowing for the increased AUW for the MR.3, this was deemed sufficient to position the CoG forward of the main wheels.

Handling does not appear to have been affected, but No.220 Squadron, which re-equipped first with the MR.3 and carried out intensive flying trials, suffered a number of incidents of the nosewheel not lowering. An accompanying photo shows WR976 with its nose on the ground at St. Moggie with half a dozen or so bods standing under the raised rear fuselage. Obviously no worries about the CoG there!

Those I have known who have built the old Frog Shack MR.3 in 1/72 have filled the forward fuselage with whatever they can find to make it stand on its nosewheel. Does make you think about how much was crammed into the real thing, though I guess the nosewheel itself would have added a lot of weight.

I think the radome first appeared on the Mk2s (taildragger). They went to nosewheel on the Mk3 because it was bigger than the 1 and 2. When they added to forward radome to make the AEW, they had to go back to the Mk2.

Edit: Confession. I still think it's a lovely looking aircraft.

Avro's Maritime Heavyweight
 

This book is available from a booksite beggining with A and not a river!

Would the tricycle undercarrage place the airframe into a better position for the Viper jet engines used for take-off? I also assume that the Mk3 had a steering nose wheel rather than a castering tail wheel, and this would have helped both ground handling and stability during the take-off run with all 6 engines going.

The Mk2 was chosen for AEW because the airframes were available that had a longer fatigue life left than the Mk3. It was known to get a "cocked" tail wheel on landing a Mk2 if the aircraft was not firmly put down, and the crew sometimes had to manually straighten it in the air after a roller. It was also known for the wheel to caster sideways and remain there during the landing - the result was often a set of burst and shredded rear tyres and a broken wheel rim.

The radome on the MR.2 and MR.3 is identical in size.

The Mk2 was chosen for AEW conversion as, again according to Ashworth, the heavier weight of the MR.3 had eaten into its fatigue life much quicker, while a number of MR.2s had been re-sparred and had their wings re-skinned under the Phase III modification.

But you are right, Courtney; it is a beautiful looking aircraft. Ugly and lumpy as heck, but beautiful.

Wensleydale-

The MR.3's inner nacelles were redesigned to house the new main undercarriage legs, with provision for a Napier rocket motor in the rear of the nacelle for use in tropical climes. That would have made an entertaining sight. It was ideal space for the Viper later on. Whether it was part of the reason I can't say. The nosewheel was fully steerable at the RAF's insistence. Avro thought it was unnecessary, interestingly.

I don't know if it was a strong factor in the shift to a tricycle u/c but, the change provided an opportunity that allowed a total upgrade of the bomb/weapons bay configuration from what had basically been a Lancaster generation WWII fit to a modern system that was similar in more than a few respects to the Vulcan (same stable anyhow). I worked on Vulcans but never Shacks (apart from occasional transits without a weapons consideration); I was familiar from training with both Shack weapons systems. Without the benefit of any 'hands on' I would be inclined to suggest the Mk 3 was a major improvement when it came to loading/off-loading weapons housed in the bomb bay. Standing by to be corrected by those with experience.

salad-dodger for the win!!!
 

And yes, it is a beautiful aircraft!

54Phan, who has "been there", as a plastic modeller and aircraft photographer.

It is rumoured that the primary reason for changing to a tricycle undercarriage was to help export sales. When the SAA expressed an interest it wanted a tricycle U/C not a tail dragger. There a many changes between MR2 and MR3. the wings are different, the MK3 having the Argosy wing and effective ailerons.
The change of main gear was effected by moving the attachment points from the front to the rear spar.

The Vipers were fitted to outboard nacelles.
The first pilot had an additional "spectacle" to operate the nosewheel steering.

The AUW of the MK3 eventually exceeded 108,000 lbs. (MK1 86,000 lbs)

Mk2 and Mk3 were the same length 87.3 ft.

Radome had four postitions up, 1st search, 2nd search and attack, there was an interlock switch on the U/C which selected up when the U/C was lowered.

pm575

Re the mini...I think you'll find that the Pope was visiting that day.