wanttaja
En-Route
I've been putting together a presentation on the pre-WWII through WWII Link Trainer, focusing more on the technical issues (how it worked) vs. the model number/history flow.
Came across a curiosity that I haven't been able to explain. Figure there's no one here that can actually *answer* the question, but there are some bright enough folks that might suggest some alternate explanations.
First, let's look at a stock Link Trainer, probably a C-3 or C-4/ANT-18 model:
This has everything you typically in a pre-1945 Link...the fuselage (with the access panel mod s), the wings and tail, the remote instructor's desk with instruments and Recorder.
Now, take a look at this Royal Air Force Link:
First off, it's a biplane... and I've only seen that in Links operated by the British Commonwealth.
The second thing is the addition of a structure on the rotating part of the base...the assembly of light-colored rods and tubing.
I've been racking my brain trying to figure out what this is for. There are poles going (apparently) down the ground, and the poles themselves extend (look at the one under the left wing vs. the right.
Here's another shot from a different angle, on a different session (the student is wearing a Sidcot suit), and possibly a different trainer:
Notice similar structures going to the nose and tail...and an external control handle added.
Here are some of my basic theories:
1. The early Links had weak power in the bank. The one I worked on, if you banked all the way over, the trainer couldn't recover. You had to pitch down all the way. Under the nose was a small section of curved wood that would act as a runner once the machine was pitched down all the way and allow you to level the wings.
This might be a way of correcting that. The vertical posts under the wing might be telescopic/spring loaded to provide an additional bit of force to let the student level the wings.
However, I've never heard of a Link having problems in pitch. Yet the above picture shows the same structures for pitch.
Another factor is I think the stuck-in-roll issue was *deliberate*. Basically simulating a graveyard spiral.
2. Compensation for the upper wing. The Link's CG went up when the biplane wing was added, and perhaps it needed a little more help to level out. Kind of doubt that...the wing probably wasn't all that heavy, and would probably have been easier to leave it off.
3. Adding stability. The stock Link is neutral in pitch and roll. The RAF may have added the structures so that the Link had positive stability. The lever in the second photo may have been to turn the stability augmentation on and off.
4. Adding a one-handle locking mechanism. The stock Link had two steel straps to lock the Trainer in roll and pitch. Handling them wasn't difficult (have done it solo many times) but perhaps the RAF wanted a single handle that stops the whole thing.
It does appear to be just a RAF thing. Here's a shot of a biplane Link Trainer in Canadian service. Note it doesn't have the structures.
You can see the manual locks clearly in this picture....the vertical silver strap running from the revolving octagon below to a stout pin sticking out the side of the bottom of the fuselage. You can also see the similar strap for pitch right in front of the instructor's legs, next to the silver step.
This kind of implies that the handle was not related to any add-on stability features...or able to lock up the whole trainer at once.
So, anybody got another theory? I have pinged the RAF Museum, but they're apparently not in full operation again.
Ron Wanttaja
Came across a curiosity that I haven't been able to explain. Figure there's no one here that can actually *answer* the question, but there are some bright enough folks that might suggest some alternate explanations.
First, let's look at a stock Link Trainer, probably a C-3 or C-4/ANT-18 model:
This has everything you typically in a pre-1945 Link...the fuselage (with the access panel mod s), the wings and tail, the remote instructor's desk with instruments and Recorder.
Now, take a look at this Royal Air Force Link:
First off, it's a biplane... and I've only seen that in Links operated by the British Commonwealth.
The second thing is the addition of a structure on the rotating part of the base...the assembly of light-colored rods and tubing.
I've been racking my brain trying to figure out what this is for. There are poles going (apparently) down the ground, and the poles themselves extend (look at the one under the left wing vs. the right.
Here's another shot from a different angle, on a different session (the student is wearing a Sidcot suit), and possibly a different trainer:
Notice similar structures going to the nose and tail...and an external control handle added.
Here are some of my basic theories:
1. The early Links had weak power in the bank. The one I worked on, if you banked all the way over, the trainer couldn't recover. You had to pitch down all the way. Under the nose was a small section of curved wood that would act as a runner once the machine was pitched down all the way and allow you to level the wings.
This might be a way of correcting that. The vertical posts under the wing might be telescopic/spring loaded to provide an additional bit of force to let the student level the wings.
However, I've never heard of a Link having problems in pitch. Yet the above picture shows the same structures for pitch.
Another factor is I think the stuck-in-roll issue was *deliberate*. Basically simulating a graveyard spiral.
2. Compensation for the upper wing. The Link's CG went up when the biplane wing was added, and perhaps it needed a little more help to level out. Kind of doubt that...the wing probably wasn't all that heavy, and would probably have been easier to leave it off.
3. Adding stability. The stock Link is neutral in pitch and roll. The RAF may have added the structures so that the Link had positive stability. The lever in the second photo may have been to turn the stability augmentation on and off.
4. Adding a one-handle locking mechanism. The stock Link had two steel straps to lock the Trainer in roll and pitch. Handling them wasn't difficult (have done it solo many times) but perhaps the RAF wanted a single handle that stops the whole thing.
It does appear to be just a RAF thing. Here's a shot of a biplane Link Trainer in Canadian service. Note it doesn't have the structures.
You can see the manual locks clearly in this picture....the vertical silver strap running from the revolving octagon below to a stout pin sticking out the side of the bottom of the fuselage. You can also see the similar strap for pitch right in front of the instructor's legs, next to the silver step.
This kind of implies that the handle was not related to any add-on stability features...or able to lock up the whole trainer at once.
So, anybody got another theory? I have pinged the RAF Museum, but they're apparently not in full operation again.
Ron Wanttaja
