Revell Type VII Build advice

[Avera]

Quite a few years back I was at the Pearl Harbor exhibit in Oahu. There is a cutout section of a submarine hull. I had the honor and thrill of meeting two WWII submariners (one American and the other German) at the same time while reading over the exhibit. For the few minutes I had, they enlighten me with small war story bits and fear of depth charges. It was an amazing experience to have both sides standing next to each other at peace sharing a common bond and telling their tales.

[He Who Shall Not Be Named]

To help further clarify the operation of the planes in my meager mind, (please correct me if I am wrong) the idea is for the sub to rise and sink while maintaining a somewhat level trim. This is accomplished by having both the bow and stern planes operate in tandem to raise each respective end when you want the sub to surface and if you want the sub to submerge, both planes should work to lower each end at the same time. I presume that the bow planes have a larger surface area than the stern plane would give it more lift (up/down) than the stern planes thus giving the sub a bit of a nose up/down respective to the stern.

Although a quicker way to dive would be to first have the bow sink while rising the stern (greater dive angle) and hope that the stern/props does not break the surface.

Would it not be easier to have one servo that controls both the bow and stern plane together? Though the connecting rods might be a bit tricky to configure.

I like technology (ADF2), but simplicity trumps everytime.

What you describe involves close coordination between the bow and stern planesman -- not an easy task for one man, which is the situation we r/c sub Driver's are in. We delegate stern plane duties, to a high degree, to an angle-keeping device. This unloads us from that chore, so we can concentrate on depth management using the fairwater/sail/bow planes. We're still in the stern plane loop, but for the most part we leave it to the angle keep to keep the boat at a near zero pitch angle.

You described the, 'Simon Lake method' of depth control, or the 'even keel' approach. First promoted by Mr. Lake back in the early 1900's.

The 'John Holland method' of depth control, or the 'pitching hull' approach, is for radical depth changes. It employees the 'lift' generated by the hull as it's forced up or down to the water flow (angle-of-attack) by the planes ... the stern planes contributing the most moment to that endeavor.

What the rest of the world submarine operators do today is a bit of both: a transition between the 'pitching hull' and 'even keel' method, to suite speed and depth orders. At patrol depth or periscope depth, the stern planesman works to keep the boat at a zero angle, the fairwater/sail/bow planesman controls depth with his planes.

When slow, you go with Mr. Lake. When scooting around fast and maneuvering like a crazy man, go with Mr. Holland.

I've stood many watches at both sets of planes and helm on the TRUTTA. I was pretty good at it. And a good watch-section will drive the boat to the commanded depth without direction or thought as to what mode you'll use -- the stern planesman knows what the bow planesman is doing, and vice versa. Anticipation of what the boat WILL do, and what will happen when your Mate spins his wheel is the key. Experience is the teacher. Oh, and the Diving Officer? His job is to slam his coffee cup off the back of your head should you get out of sync with the ship control party. Oh, and I should mention, he'll tell you what angle to go for or not exceed.

Below a critical speed, when operating the planes in the pitching hull mode, you get into the 'Chinese planes' phenomena -- where the static stability of the boat overcomes the pitching force of the stern planes, and things go backwards on you.


... but, that's another story.

David

[Avera]

To help further clarify the operation of the planes in my meager mind, (please correct me if I am wrong) the idea is for the sub to rise and sink while maintaining a somewhat level trim. This is accomplished by having both the bow and stern planes operate in tandem to raise each respective end when you want the sub to surface and if you want the sub to submerge, both planes should work to lower each end at the same time. I presume that the bow planes have a larger surface area than the stern plane would give it more lift (up/down) than the stern planes thus giving the sub a bit of a nose up/down respective to the stern.

Although a quicker way to dive would be to first have the bow sink while rising the stern (greater dive angle) and hope that the stern/props does not break the surface.

Would it not be easier to have one servo that controls both the bow and stern plane together? Though the connecting rods might be a bit tricky to configure.

I like technology (ADF2), but simplicity trumps everytime.

[alad61]

I found it helped to have all the tx to rx to servo settings set on your planes before you hook up & tune the adf.... and after several hours the temperment changes, the clarity of thinking slides and it looks like the whole thing is a against you... thats when you just walk away for a day or so. Well thats what I do (most of the time. LOL!! )

[Avera]

I should have figured that out myself.

I have not connected the stern planes but judging by the movement of them, if they point down then the stern should rise, the opposite of the bow plane if my logic is correct. Just need to check which way the servo moves when the knob is turned.

I just realized that my problem was with definitions and the ADF2 instructions. Pitch control meant the stern plane when all along I thought if was referring to the bow plane which I control on the TX. Just a simple error and hours wasted.

Andrew

[trout]

Which way makes your stern planes cause your stern to rise?

[Avera]

I see, I was adjusting the forward planes not the rear when I was calibrating the ADF. So the proper way of setting the ADF Pitch Control under the included instructions (Number 1 and 2 in the ADF2 instruction guide) is use the knob on the transmitter (channel 6 - rear plane) and NOT the bow plane control. The #2 step in the guide says:

"Command full rise on the planes of your transmitter, and while holding full rise push and hold the setup button again until the flash pattern changes to a solid green."

So my next question is which way do I turn the channel 6 knob for full rise; clockwise or counter clockwise?

[He Who Shall Not Be Named]

Trout's experience may be yours, Avera.

Or ... maybe you're not giving the ADF time to run through its start-up protocol when you turn on the mission switch?

David

[trout]

I had something very similar happen, I was adjusting the wrong plan on setup. I was adjusting my bow plane and not the stern plan. Resulting in zero plan movement.

[Avera]

Hi Folks,

Got the new 8 Channel RX, works a lot better. In the process of adding foam and doing the trim. In the meantime, I think the ADF2 is not functioning well. I removed the Lipo Guard from the servo connections so only the ADF2 is attached to the servos this way of reducing the variables. I went through the programming several times. Channel 4 is my ballast and that appears to work by TX control and as failsafe. When I turn off the TX, the ballast is automatically blown. The problem is the pitch controller. That does not work via the ADF2. The servo works if wired directly to the RX channel 6 and can be controlled via the knob. When plugged to the ADF the servo does nothing. Cannot control it by knob on the TX and if I pitch up or down the equipment tray, nothing. No movement to the servo. However, if I try to manually push the servo arm, I get resistance. Note that the orientation of the AFD is sideways attached via double side tape to the metal bracket holding the servos. I checked the polarity on the connections and they seem to be correct.

It is my understanding that the ADF2 should be adjusting the rear planes as the submarine pitches up/down to level it, I tried to simulate a dive by orienting the equipment tray down while commanding the TX to dive, but there is just no movement coming from the rear plane servo.

Any ideas or suggestions.

[He Who Shall Not Be Named]

Undeniable truth there.

David

[Avera]

Its true that a boat is nothing but a hole that you dump money into either real or model.

[He Who Shall Not Be Named]

Yes, the yellow boxed receiver from Sombra Labs is the SL-8. No issue at all with the transmitter you mentioned.

[Avera]

Hi David,

Are you referring to the yellow SL-8 receiver sold by Caswell for $64? If not, please point me in the right directions (which model and website) and I'll pick it up. Bear in mind that I have the 6 channel WFly transmitter; I don't think using an 8 channel receiver will be an issue with a 6 channel transmitter.

[He Who Shall Not Be Named]

HI David,

Thanks for the reply.

There are 30 crystals (Channel 61-90) listed on that link, from what I understand anyone should work as there are all 75 Mhz. Anyone better suited than the other?

Andrew

It has to be on the 75mHz band (USA), of the UM-1 type (mini size), single-conversion, FM, and PPM capable.

Wouldn't it be easier, toss in the extra coin and get Aroosh's SL-8 with its synthetic crystal, so you don't have to go through all this bull-****?

David