Albacore bow planes

[greenman407]

Since I have used my Albacore as a test bed for testing I decided to use it to test the Traxxas waterproff servo instalation outside the wtc to power some bow planes that I had been toying around installing. The Albacore at periscope depth worked fine without bow planes at scale speeds. But when you tried to go fast it would move up and down about two inches continuously and would get worse the faster you go until it would become uncontrollable. So out came my scale drawing of the Albacore. I found some left over planes so I cut them down to the size shown on the drawings.
Planes marked to size and ready for trimming

cut to size and shaped

bushings ready for instalation in hull

[greenman407]

http://www.postimage.org/aV1JqLt0.jpgmarks applied to the hull

marks applied to the hull at proper location

holes drilled

a length of shaft to hold bushings in alighnment during the CA process



bushings installed

[greenman407]

http://www.postimage.org/Pq1Lmlpi.jpglooking good in position

http://www.postimage.org/aV1JsiKA.jpgfrom inside

looking good in position

from inside view you can see 5/32" tube and dubro locking collar with a brass arm brazed on

servo extentions and line splitter

Traxxas waterproff servo

testing for proper point of installation

[greenman407]

In order to hook it

In order to hook it up my plan was to drill a hole in the end cap and use a servo extention wire to run from the front of the sub and go in the back plate of the wtc and hook it up. There was some controversy as to how to hook it up. My plan was to install the line splitter after the apc and before the mixer for the X-tail that way I could control all planes from one stick and have them all controlled by the apc. Everything that I had read on this forum told me that it wouldnt work. Well I just had to try it. More on that later. Now some more pictures.
drilling hole. Not for the faint of heart

hole

line splitter

exitting servo control line to plug into bow mounted servo

bellows seals purchased on ebay to add additional sealing to pushrod seals

installation complete

additional foam installed at waterline to help make up for the added weight of the servo and hardware

[greenman407]

Well you say, How did

Well you say, How did it work? I had expected that it would be like a dolphin jumping in and out of the water. Not so. By using one stick to control both bow and stern planes it actually worked well. I like having bow planes as you can move along on the surface at good speed without the sub trying to dive on you and the stern sticking up out of the water with the prop spinning wildly. Also it showed increased manuerverability in the up and down plane. The negative was that I saw no improvement in the afformentioned up and down movement at fast speeds. It was felt by some that if I made the apc as insensative as possible that would do the trick. Not so. At least not with this sub. So then I moved on with the next phase of the tests. I connected the bow planes to the left stick control and left the stern planes hooked up with apc on the right stick controls. AS I was preparing to test this setup disaster struck. At this point the much vaunted Traxxas waterproff servo proved to me that it is NOT WaTeRpRoFF!!! It bacame erratic and then quit altogether. So for the last phase of the test I put it back in the water with the bow planes fixed. At this point I saw a great improvment in its high speed handling. Now it only moves up and down about a half inch at wide open throttle and is completely under control. Apparently the extra surface area of the bow planes creates a stablizing effect on the hull. The next step is to send in the offending servo to tower hobbies for exchange. In the mean time I have another one that I am going to seal all possible points of water intrusion with silicone and install a ss washer and o-ring along with silicone grease at the threaded post. Stay tuned for updates.

[greenman407]

OK so today was another

OK so today was another day of testing. I carefully siliconed all areas that I thought that water could possibly get in including installing a oring under the servo arm and smeering it with silicone grease. So far so good. It will take a couple more trips to the lake before I announce success. But the bow planes are a nice addition to the sub.

[g2tiger]

Greenman,

Hows the sub these days?

Greenman,

Hows the sub these days? Whats the happs with the bow servo? Some of us up here in Jax were thinking of using the same servo in the same way. Was your first one defective?

Charlie

[Rogue Sub]

Didnt Warren buy like 30

Didnt Warren buy like 30 of those servos and try them out with success?

Mark
Did you think about putting an oring on the shaft and plasti dippign the servos?

Charlie
Get your boat underwater.

[nzkilo]

I have found that basic

I have found that basic water proofing of servos will work for a while, but ideally replacing the air gaps inside the casing is the way to go.
I did some research some time ago for creating a 'deep diving' rov and how the pros did it. As you all probably know, most external motor casings are oil filled to counter the pressure.

I found this link the other day on some methods to water proof servos.

http://www.societyofrobots.com/actua...of_servo.shtml

[greenman407]

Hi Charlie! The first servo

Hi Charlie! The first servo became water logged, not a very good thing for a water proof servo. So I called Traxas and they sent me a new one with the understanding that there servos are not made to dunk under the water. What they designed it for was water splashing on it as in RC model cars splashing thru a water puddle. So I coated all the seams and screws with goop and put a siliconed o-ring on the output shaft but under the servo arm. So far so good. However only time will tell.

[greenman407]

http://www.subcommittee.com/forum/icon_biggrin.gif Hello again. The last

Hello again. The last time that I did a test with this sub before I had to retire temporarily it did something unusual. When I dive a sub I usually leave the planes at nuetral and just flood the ballast tank and it goes right on down. This time at this point I didnt touch the rear planes at all. I used the front planes only to take it further down. To my surprise with full dive on the front planes it would only go down about 18". The only thing that I can think of is that the APC is interfering with the boat going down. Since this is an X-tail the rear planes have a whole lot more surface area than the fronts do and can easily overpower them. Jeff Larue suggested that I disconnect the APC and test the theory. Thatll be the next step. Lately my time for hobbies has been severely dampened, what with moving and OMG moving again and working on two houses at the same time trying to keep the little woman happy.Hopefully by Thanksgiving I will be able to get in some more testing.

[rpmtech1]

Your diveplane pivot point is

Your diveplane pivot point is not at the M.A.C of the diveplane. it will become unstable the faster you go. Maybe this is causing problems..

Basically you need to move the pivot point forward. 25-30% from the leading edge. so if your diveplane has a root chord of 1", you want the pivot shaft about 1/4" to maybe at most 3/8" inch back from the leading edge.

[greenman407]

Hi and thanks for the

Hi and thanks for the reply. Im sorry, What is the M.A.C. of the planes. I think that what you are suggesting is that all control surface mechanisms have a little bit of slop to them and that if the pivot point is not favoring the leading edge the slop will allow excessive movement of the planes. Could be. I notice that the X-tail planes themselves have more slop in them than I would like to see. I will have to check and see if the pivot points on them are centered or are biased more toward the leading edge as you suggest. However that problem is almost cured by the addition of the bow planes.

[skip asay]

Regarding your Albacore "X" tail

Regarding your Albacore "X" tail control surfaces and the "slop" they seem to have, I would check your linkages very closely.

Since Dave M. made those up, I think it's safe to say that the pivot point is correctly located. In other words, DON'T try to change them.

Skip Asay

[stark]

Like Skip would know http://www.subcommittee.com/forum/icon_rolleyes.gif

Like Skip would know

How you doing Skip, NC treating you ok?

Brian