8mm Forum: 16-CL question

This is topic 16-CL question in forum 16mm Forum at 8mm Forum.

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Posted by David Pannell (Member # 300) on January 27, 2008, 11:19 AM:

Having had intercourse of the communicatory kind with Kev regarding various aspects of this projector, an anomaly appears to have arisen.

Does it have a 2 or 3 bladed shutter?

Mine has 3 blades, Kevin's has 2 blades, and apparently the manual only refers to 2 blades. Mine is definitely and without question OEM.

Can anyone shed any light on this one? Are US models different from EU models, or is it maybe to do with age / serial numbers?

Hopefully someone has the answer.

Best regards,

Posted by Kevin Faulkner (Member # 6) on January 27, 2008, 05:20 PM:

I know of three std CL's which have 2 blade shutters and not 3. One being my own.

As David said it would be good to know what shutters others have in their CL's.

Thanks, Kev.

Posted by Hans van der Sloot (Member # 494) on January 27, 2008, 06:19 PM:

Mine all have 2 blade shutters:
- 16-CL std. (M&O)
- 16-CL Deluxe (M&O)
- 16-CL Xenon (M&O)

Posted by Maurice Leakey (Member # 916) on January 28, 2008, 02:35 AM:

The service manual only shows a two-bladed shutter and makes no mention of a three-bladed.

Maurice

Posted by David Pannell (Member # 300) on January 28, 2008, 08:56 AM:

Mine is optical only and sound speed only. Does this make any difference, I wonder. [Confused]

Posted by Maurice Leakey (Member # 916) on January 28, 2008, 10:43 AM:

David

I searched on the Net and found that Elmo shipped the CL with two and three bladed shutters. It appears that the 2-bladed gave more light, however, I did find a comment which said:-

"I find 3-blade shutters to be much easier on my eyes."

There is a firm in the USA who supply five bladed shutters for CLs to be used for flickerless video transfer.

Perhaps that was implied by the remark above. Less flicker effect with the 3-blade?

Maurice

Posted by Jeff Chaney (Member # 1025) on January 30, 2008, 11:39 PM:

I have 4 elmo CL's
2 of them have the 2 blade shutter which have somewhat large notches, 1 of them has the 3 blade which has very thin notches in the shutter and then i have one with the 5 blade shutter which also has the thin notches. I think it might have something to do with the age of the projector as my 3 blade is newer than the 2 blade ones.

The 5 blade shutter works perfectly for home telecine.

Posted by Maurice Leakey (Member # 916) on February 01, 2008, 04:05 AM:

The Movie Maker test report of August 1977 says:-

"The projector is intended mainly for the projection of optical sound films at 24 f.p.s., and the shutter has only two blades, each of 60 degrees. Two blades are of course entirely adequate for large-screen projection at 24 f.p.s., but render the machine unsuitable for projection of silent films at 16 or 18 f.p.s. because of flicker."

In their summing up they didn't like the difficulty of changing the speed to 18 f.p.s., and the bad flicker at that speed.

So, perhaps, the three-bladed machine sacrifices some light in order to reduce flicker at the slower speed.

Maurice

Posted by Kevin Faulkner (Member # 6) on February 01, 2008, 06:54 AM:

I wasnt aware that it would run at 18fps.

Have just found this in the Manual and it seems you can but providing the Hz hasnt been changed?

Kev.

Posted by Jeff Chaney (Member # 1025) on February 01, 2008, 11:22 AM:

That part of the manual is a bit deceptive since every CL I have ever seen only has the pulleys to change the Hz. I have never seen one with the pulleys to change the speed.
Cheers
Dino

Posted by Kevin Faulkner (Member # 6) on February 01, 2008, 04:58 PM:

Yes I must admit that I found those instructions a little strange.
The way I read it is that if you have a 50Hz machine and change the pulley to the 60Hz setting you will get a slower speed etc. Obviously doesn't work for a machine set to 60Hz from the factory.

Think thats the right way round.

Kev.

[ February 23, 2008, 04:16 PM: Message edited by: Kevin Faulkner ]

Posted by Maurice Leakey (Member # 916) on February 02, 2008, 02:40 AM:

The CLs instructions are ambiguous and I quote once more from the Movie Maker review (August 1977).

"........alternative pulleys are provided, so that by changing over the belt (rather a struggle) the running speed can be changed to 18 f.p.s. The handbook also suggests that this alternative belt position can be used to give 24 f.p.s. running on a 60 Hz mains frequency - but, as the ratio 24/18 is not the same as 60/50, obviously it cannot do both! The ratio chosen does, in fact, seem to be a compromise, and our test machine ran at about 19 f.p.s. in the '18' setting."

The instuction book can only really refer to a machine set to run by the factory at 50 cycles. You can change the speed or the cycles, but not both together. Would the reciprocal suggestions also work on a basic 60 cycle projector?

I also have a Bell & Howell TQIII which does not have a silent speed setting but does have a lever under the lamp housing marked 50 - 60. By sliding the switch the drive belt is flicked onto another pulley. Thus at the 60 cycle setting (on GB 50 cycle mains) the projector runs at a slower speed which is suitable for the showing of silent films at 18 f.p.s. although I don't know exactly at what speed it runs. But my same comment above refers to this, I assume that if this same machine was used on a 60 cycle mains (and set at 60) a change to the 50 setting would make the motor run faster than 24 f.p.s.

Maurice

Posted by Kevin Faulkner (Member # 6) on February 02, 2008, 04:37 AM:

Right that makes sense. So a machine in the US doesnt have any chance of running at the slower speed just European 50HZ versions.
Anyway that doesnt answer why Elmo have used either 2 or 3 blade shutters when they know that most of these machines if not all will be running at 24fps.

Kev.

Posted by Maurice Leakey (Member # 916) on February 02, 2008, 05:48 AM:

Kev

I suggest that when the owners of new CLs in 1977 slipped over the belts to select silent speed they were plagued with flicker.

So perhaps Elmo then introduced the 3-bladed shutter to reduce this problem?

Maurice

Posted by Richard C Patchett (Member # 974) on February 17, 2008, 09:23 AM:

Greetings
The 2 blade was used in the schools to show short distances. These were the early models. The Latter models came with the 3 blade.

Posted by David Pannell (Member # 300) on February 20, 2008, 06:06 AM:

OK,

1. The fact is, that my machine with the 3 bladed shutter has 3 large apertures, not slits.

2. The ratio of 50Hz to 60Hz means that on a 50Hz supply, with the belt in the 60Hz position, the projector will run at 19.999fps.

3. Therefore, on a 60Hz supply, with the belt in the 50Hz position, the projector will run at 28.8fps.

4. There is absolutely no facility on my 16-CL for actually changing the frame speed.

I reckon that 20fps is a bit too fast for silent movies, so, indeed, the instruction manual is TOTALLY misleading!

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