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  #1  
Old 11-07-2010, 05:01 PM
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jharding58 jharding58 is offline
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Default Saturn V (2157) build question

Has anyone built the current SV and found a problem with the LM stage centering rings? Both the rings seem a little small for the section of tube to create the stack. Gappy and a little thin for my taste also. Not sure if I have an early kit or if this is just the regular state of affairs. I seem to remember really having to tamp the rings down into the sections of tube to build the torus in step 5 and step 7 - these just drop in and float around. I really prefer to have a solid contact on the card parts as opposed to filling with glue that I know will one day fail.
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Old 11-07-2010, 06:21 PM
Bravo52 Bravo52 is offline
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I did have the problem you are discribing with the main motor tube to the first stage tube. The others fit perfectly.

Someone else pointed out the problem with the undersized CRs that when glued in they tend to pull the BT in and create a "dimple" in the BT. I had that also on the main tube and decided not to try and fix it. Hopefully paint will "cover" enough to hide the flaw.

One thing I would recommend in your case is to carfully glue the CR in place with the coupler in the main BT (just tack it in while being carful to not glue the coupler in ) That way, it won't distort the fit too badly.
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Old 11-07-2010, 06:47 PM
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If it were a die cut part you attribute that to wear in the die, but this is a LC part. I have no problem with the three rings in the main BT - they fit perfectly, squeak when they are dry fitted. Just the LEM adapter tubes. More curious since the inside dimension perfectly fits the SM tube. Wobblies in the production department. In the interest of clarity this is the current version of the 2157 release.

BTW, find the section in the instructions listing where to assemble the third stage and the LEM/CSM sections together...
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Old 11-08-2010, 03:32 AM
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Let's try this one. Could someone show me the fin fairings attached to the base of the model? According to the instructions the lower wrap is three inches tall. The BT is marked at a 3 inch line and the wrap applied. This placed the lower wrap edge even with the lower BT edge. The hold downs are about 5/16th from the lower lip.

The conic fin fairings (leaving 2mm glue edge except on the curved relief for the BT) are 3 1/4" from the base to the tip of the cone. I can go with the idea that the fairing would overlay the lower corrugations on the wrap. I can appreciate that the upper lip of the fairing overhangs the wrap by 5/32 or so. What I cannot get to work is the fit of the fairing between the hold downs unless they are supposed to be a little bit lower on the tube. I left barely a 16th of the wrap at the top edge and that is smack on the 3" line, so how did I screw this up? Based upon the bottom of the fairing the fin base is supposed to be about 1/8 from the BT lip and then the tube is cut away between the fairings. So do I relieve the gluing edge of the fairing where it meets the hold down?

I am not usually one to whine, but I have to build four of these things. Has anyone got photographs of their alignment which worked perfectly?
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Old 11-08-2010, 09:46 AM
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I have not built one in a while, but as I recall, the hold-downs were slightly below the lower edge of the BT. I'll try to get a pic of the ancient one I am restoring if no one else reponds.
Allen
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Old 11-08-2010, 11:11 AM
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Maybe these photos will help:

Saturn V SA-500F photos

Drop down to image KSC-66-15514. It shows the fairings and the bottom edge of the tank structure, relative to the hold-downs.

Another good image is KSC-66-15529.

For the Estes kit, the tip of the fairing should be just slightly above the corrugations of the wrap. Maybe 1/16", or 3/32", above this line.
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  #7  
Old 11-08-2010, 01:28 PM
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Thanks for the scale documentation. I really would like to see a built 2157. While the instructions provide the guidance to cut, sand and fit, the fairing with 2mm attachment wings will not fit within the span of the hold-downs. If anyone has a 2157 built either the 30th Anniversary or the current stock and could shoot a couple of images of the fin/fairing attachment it would be very helpful. I noticed on the box lid picture that the hold down is halfway down the gunmetal section of the fairing.
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Old 11-08-2010, 06:52 PM
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Not sure if this helps, but this is the Centuri Saturn V I built last year, and I believe it uses the same wraps as the newer Estes models. Part of the tube and wrap are cut away to form a notch. The pics below are with, and without the display nozzles in place.

I took a quick glance at the new Estes model and it seems very similar to the Centuri wraps.
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Old 11-08-2010, 06:58 PM
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Found a couple of my build shots...

BTW my build thread is here
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Old 11-08-2010, 07:40 PM
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Thanks for the assistance. I think what I am seeing is that the fairing is fitted within the outline on the wrap - that is that where the stringers end and not on top of the stringers. If you have any chance at all to take a picture looking directly up the aft end of the model with the display nozzels removed. The contemporary version uses the base of the fairing to seal the fin inside - hence the flat segment of the fairing is glued to the curved tube surface. This is what I think is givig me fit issues. To get the fairing to curve in order to fit within the triangular stringer cut-out, and not on top of those stringers, the aft plate wants to buckle. I think it might just be easier to remove the base (of the fairing), install the fiaring, and then either add some trusses inside or fab a new flat plate to close it off.

On the next one I think I may just bite the bullet and install the Sirius Rocketry replacement fairing/fins and be done with it. It might be a rewarding experience, but this is taking too long to do - and there are too many to finish.
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