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Old Feb 13, 2014, 12:36 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
A bit more progress

With the hull painted it is time to get back on the mechanics. The rudders and dive planes are in as well as the prop shafts and props. Lots to do on the props. There is one right hand and one left hand. I need to determine which side of the boat the props should go and then I will need to reprogram the Brush-less ESC's to get the shafts rotating in the right direction.

With the limited space to work on the rudder and planes installation and my meat hooks for hands it is quite a struggle. After getting everything set up, two problems showed up. For the planes, the servo for the aft planes does not center properly. I swapped the rudder and planes at the RX and the problem persisted with the aft dive plane servo. This will have to be replaced. It is a Robbe 110 BB MG but I think the Futaba S3001 is the correct replacement. I might look for the Robbe locally.

Another issue is a bit of back lash in the rudder system. I do not get a good return to center with the rudders. One of the rudder posts seems to be a slight bit oversize causing the rudder to be a bit on the loose side. I am not too worried about this as I can fiddle with the stick on the TX a bit to get them centered. Replacing the rudder tube is not an option at the moment.

So, the servo will be replaced and then it is off to setting up the props and the dive system.

Until next time,

IR3
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Old Feb 13, 2014, 06:55 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
Rudder Problems Solved

Well, after giving the rudder problem a lot of thought the problem has been found. The geometry was wrong on the horn. It should have been on the other rudder post. This not only makes the line of the push rod correct but also has the rudders following rudder stick on the TX. It was quite involved since I needed to redo the cross coupling between the rudders. A very lengthy process.

The problem with controlling the dive planes is that the LTR6 needs to be calibrated. It does not know what level is as of yet so it has no reference to level the dive planes. The servo is just fine, just an LTR6 calibration.

Until next time,

IR3
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Old Feb 14, 2014, 11:20 AM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
The problem with the dive planes servo is solved. The LTR6 is a very clever device. It is internally set for a depth of .4 meters or about 1.3 feet. It has a very sensitive pitch sensor and a depth sensor. The pitch sensor, when at periscope depth, helps keep the boat on an even keel. The LTR6 has a connection for a 3 position switch which allows 3 modes, off, relative depth, and absolute depth. With no switch connected, the device is in absolute depth mode. Since the Tech Rack is on the bench it is not at a depth of .4 meters. Therefore the device is commanding the planes to achieve the absolute depth and thus very little control from the TX. With the switch connected and in the off position, complete control of the dive planes comes from the elevator stick of the TX.

These Engel devices are very well thought out and it takes a bit of time to fully understand how they operate.

Until next time,

IR3
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Last edited by ir3; Feb 14, 2014 at 11:27 AM.
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Old Feb 15, 2014, 12:45 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
After doing all of the work to create a removable tail cone, at 3AM I awoke with an epiphany. Why not just add a few flood holes in the tail cone to get access to the grub nuts on the prop shaft couplers. A little touch up paint and one will never know.

That being done I can now get started on setting up the props and make sure they are turning in the right direction.

Until next time,

IR3
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Old Feb 16, 2014, 08:15 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
Prop Shaft Alignment

There is not much to report with visual looks but the prop shafts are now aligned and spinning in opposite directions. Now I just have to make sure I have the props on the correct shafts. Getting the shafts aligned is quit a process. If the stern cone was exact, the strut supporting the dive planes bearing, and the prop hub is accurately brazed then everything might just line up properly with no friction to speak of. Not so fast. It took about 6 hours of fine bending on the prop hub, filing the fairings where the prop shafts exit the hull, and making adjustments to the center strut (I believe it might be called a skeg) and aligning the prop hubs themselver (adjustments in 3 dimensions), makes it quite a task. But the work on the aft section of the sub is complete. Now it is into the WTC and I can set up the forward planes. I have some mechanical advantage issues to work out. I used the notches recommended in the plans for the dive plane bellcrank but I am not getting much deflection with full 90 degree servo motion. Hopefully this will be a simple change of where I connect the dive planes pushrod on the bellcrank. Lots of work!!! I think this is the toughest of the Engel boats to set up. I guess I am just a glutton for punishment.

Until next time,

IR3
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Old Feb 17, 2014, 04:28 AM
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The Netherlands, FR
Joined Aug 2008
629 Posts
Hi ir3,

To test your LR6 you can take a 0.5 meter long silicone tube fill it with 0.4 meter of water and connect it at the pivot on your LR6.
Now when moving the silicon tube upwards and downwards when the LR6 is stationery you can simulate the water depth and that way also the reaction of the LR6. works great with the LR5 I use in my Engel Gato.

Jan,
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Old Feb 17, 2014, 10:25 AM
ir3
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Joined Dec 2007
294 Posts
Hi Jan,

Nice to hear from you. Thanks for the input on testing the LTR6. I am having so much trouble with the stern planes, I ripped out the bell crank and all of the other linkage and I am reverting to your method with the ball link on top of the brass control arm. I should have done that in the first place.

Update coming later today.

Iran
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Old Feb 17, 2014, 08:59 PM
ir3
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294 Posts
Hi Jan,

I just completed the conversion of the Aft Dive Plane linkage. When I exercise the planes servo I get very little deflection of the aft planes. I am enclosing two pictures, the aft linkage and the servo linkage. With the current servo arm at a full 45 degrees each way from center I get perhaps 10 degrees of dive plane movement.

Have you hooked the aft planes up to the servo yet and if so, what kind of deflections are you getting. Is it possible that most of the pitch action will come from the forward planes?

Hope to hear back soon.

Cheers,

Iran
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Old Feb 18, 2014, 04:58 AM
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The Netherlands, FR
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629 Posts
Just the copy of the PM I send you but I see now you are asking the same question here so I put it here also.

Hi Ir3,

I have indeed used the biggest servo horn I could find fitting my servo to make the stroke longer.
But I remember for sure now that I shortened the bras hevel what is attached at my stern plans what will increase the trow dramatically.

Regarding the bow planes.
Experience from fellow u-boot modelers is that the authority from the bow planes are not that prominent. Working together with the stern planes will help of course but thats only by try and error.

So I recommend to shorten the stern hendel attached at the stern planes and find a bigger servo horn. That will solve your problem.

Take care,

Jan,
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Old Feb 18, 2014, 11:42 AM
ir3
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Hi Jan,

I lowered the dive plane control arm and moved the servo push rod out as far as I could and still keep the servo arm from hitting the WTC tube. I am getting a bit less than 15 degrees deflection on the planes. I could shorten the arm some more. I believe there is enough room. Are your pictures on your build thread up to date or is the arm that you are showing in one of your pictures now much shorter. Do you have a measurement for the length of the arm?

Thanks,

Iran

THE CURRENT RATIO SHOWS THAT FOR 45 DEGREES OF SERVO TRAVEL, I SHOULD GET ABOUT 13 DEGREES OF PLANE ANGLE. I CAN PROBABLY GET THAT TO ABOUT 20 DEGREES IF I SHORTEN THE ARM BY ANOTHER 1/4 INCH. THIS WILL PLACE THE BALL DOWN INTO THE NARROW AREA BUT THERE WILL STILL BE SOME ROOM TO GET THE PUSH ROD ATTACHED.
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Last edited by ir3; Feb 18, 2014 at 12:28 PM. Reason: Clarify plane angle adjustments
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Old Feb 18, 2014, 02:18 PM
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The Netherlands, FR
Joined Aug 2008
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Hi Iran,

The photo you mention is indeed not actual anymore I have shorten it afterwards a bit more.
I have take a look a few minutes ago and have taken some photos to explain how I solve this tricky problem.

First the mid of the servo does not put the sternplanes in neutral angle but already a bit downwards,





Then by full down the servo at 45 degree,





And full up the servo at 45 degree,





This the actual situation and I hope it explain enough to get you trough this.
By the way the aft stern horn are from center boll ink to end of horn 25 mm or almost 1 inch.

I hope it is enough when she finely hits the water but I guess that you are there faster then I Iran

Regards,

Jan,
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Last edited by Horseman; Feb 18, 2014 at 02:20 PM. Reason: grama
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Old Feb 19, 2014, 01:55 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
Thanks Jan,

I did a little bit more work on the stern plane geometry and I am now getting about as much stern plane movement that you have achieved. Looking closely at the Engel assembly manual, the linkage is well into the opening in the stern plane support.

I shortened the control arm and placed the ball link in the center. In that way I will not get any interference from the sides of the stern plane support.

I am now getting about +- 18 degrees of deflection. This should be more than enough. I also plan on linking the bow plane into the LTR6 allowing for more help when changing depths.

I have a lot of hours in this and I will do no more on this linkage. As the famous Porky Pig always says "Deb-ebe-de-deb-de that's all folks!"

This has been a lot of work and a good deal of it very frustrating and at this point not worth the effort. I am actually sorry I tackled this boat instead of one of the Merriman 1/72 scale boats, which I juts might go back to. There is actually no clear water pool large enough for this sub in my area. The most I am going to be able to do is use the largest swimming pool that one of our friends has and do a little surface movement, drop to periscope and do a bit of under water movement. The turning radius is so bit that I probably will not get a complete turn without backing one of the props. There is no pool in the area large enough to test the full functionality.

Once it is done and I have played with it for a while, it will go.

Thanks for all the help on this thread, especially from Jan. I won't be doing anymore updates since there is not much more to show. All of the really big problems have been solved.

IR3
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Old Feb 19, 2014, 09:07 PM
alligator
Venice Fl.
Joined Jul 2004
168 Posts
Excellent work Iran, you have persevered with this Engel model thru hell and high water. Your patience has paid off, as both you, and Jan have produced well thought out results to the issues encountered. Congratulations are in order.

I somehow ponder over your most recent comments however, That you don't have a large enough pool in your area to fully test and enjoy running this beautiful model.

Did you somehow overlook that fact prior to entering into this project, or was it simply for the challenge in building this model that you apparently overlooked that detail. :- )

Enjoy it, whichever way you can,

Al,
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Old Feb 20, 2014, 12:30 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
Hi Al,

Thanks for the comments, much appreciated and I am sure Jan feels the same.

When I first thought about the boat, there was a sub mariner that used the pond at Hansen Dam. You might have followed the Hansen Dam Irregulars on RCG. At that time I thought it would be great so after searching the web, Engle submarines popped up. I was fascinated with all of the electronics and the Type VIIC U Boat was my choice. As the thread showed, it was a very difficult build and was put in mothballs several times. Now that the mechanics are all working I started getting a bit nervous about using the two local ponds. They are not very clean.

So I can do some test runs in a swimming pool just to check the ballast tanks and calibrate depth and running at various depths. The turning radius is too big for most of the swimming pools that I have access to.

If I am really hyped up after the swimming pool tests, I can travel to the San Diego or San Francisco model boat clubs. I think both pools are clean enough to follow the boat under water.

So that's it. For other potential sub mariners I actually recommend the Type VIIC from Engel. He made many upgrades since I purchased my kit. That was part of my problem, updating my kit to current. It just didn't work that well.

I will probably repost after I get near the finish line on the build.

Until next time,

Iran
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Old Feb 23, 2014, 06:12 PM
ir3
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United States, CA, Los Angeles
Joined Dec 2007
294 Posts
I have a question. I am not 100% happy the location of the RX in the Tech Rack. It is at the forward most end of the tech rack and the space is quite limited. It is also difficult getting all 8 leads plugged into the end of the RX.

I found a better spot. One of the spacers for the for ballast tank mounting has a very nicely sized opening. It is where the spacer that has the VIIC symbol carved in it. The only problem that I see is that the RX will be just above the Ballast Tank motor. Engel claims that the motors on the ballast tanks are suppressed.

Should I worry about interference from the ballast tank motor? The new RX location quite handy and will significantly shorten a lot of the wiring. I have no problem making/shortening new leads, I just want to make sure that I am not creating a problem for myself.

Any comments either way would be greatly appreciated.

Thanks,

Iran
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