Newbie no more - Building the Revell 1/72 Gato

[trout]

Al, Thank you for your help. I will try not to get myself in a tissy (thank you for making me laugh). I will do as you have offered and you are so right about compromising the seal, hence my concern.
Your Gato is an inspiration!

[He Who Shall Not Be Named]

Run a 1/16" bit through there at low speed, and hope for the best. There are more seals where that one came from.

David

[beeryboats]

Run a 1/16" bit through there at low speed, and hope for the best. There are more seals where that one came from.

David

Maybe turn the drill backwards? Use friction and not cut it?
Just an idea.....
Jay

[He Who Shall Not Be Named]

Sure. Whatever! ....

Stop over thinking this ****, damit -- we're not assembling Critical assemblies with the shank of a screwdriver here!

The object of the game is to bore out the resin, not the rubber. The rubber will squirt out of the way of the bit blades, the resin won't.

David

[trout]

David, I am sure you are right. My parents use to tell me when my oldest brother was born every injury or sneeze they would go to the doctor or ER. Then by the time I came around (I am theyoungest) it was more the attitude of just rub dirt in it and move along or that gash on your head, we'll put a butterfly bandaid on it and keep playing. LOL
I will get to the point of knowing what is rocket science and what is not - for now it all seems like critical assemblies!
Happy New Year to you all - looking forward to a wet 2012!

[He Who Shall Not Be Named]

LOL. Good point. You're right: with experience one does get jadded. At one time I was tip-toeing through this stuff for the first time, and it all seemed do damned critical that things were done, just so. With experience you find what has to be kept tight and what can just slide.

Oh ... happy new year!

David

[trout]

Had trouble with one of the push rods being very hard to move, I went ahead and put a 1/16” rod in and slowly turned it with silicon oil. After several tries it seemed to be moving better. We will see later how water tight this is.
I had started to install my push rods when I thought I wonder how the fit is with these servos mounted......barnacles, it didn’t.

I had choices, I could grind the center divider down, this would move the servos closer to centerline and bring the servo arms in. This sounds good, but I have seen the receiver stored there in between the servos so if I eliminate that space were does the receiver go?? I am learning that space is a premium. So next choice....
I could cut the bottom out and move the servos down allowing the widening curve of the tube give room for the arm. This is a better choice, but I want to have a SNORT system in place it goes below the servo deck.

If I move the servos down enough to allow the arm to swing, there would be NO room for the SNORT pump. So next choice.....
Why not lower the server AND cut the arm back? A combination of cutting out the bottom of the tray to lower the servos and trim the servo arm back. But how far would I need to trim....I needed to find that out.
The servos span ~58mm and that is just to great a distance to accommodate.

So I marked with tape where the arms touched the tube.

Then eyeballed about where the server could be placed and still have room for the SNORT pump below. It looked like I could use the fourth hole from the center for the push rod.
using some calipers I measured the distance and tested that in the tube to see where it met with a little room for the plastic needed around the 4th hole.

Yep I think we have a winner. Peeling the servos out of the RTV was not too tough to do. It looked like most of the support will come from the resin center piece and not the areas below the servos themselves.

Off to the bench to cut and remove the bottom pieces. I used my jewelers saw to cut on each side of the bottom aluminum plate. Then scored between my two cut lines and bent the metal until it snapped off.

Then did a little clean up on the edges with a file.

And the finished tray.

and a test fit with the arms trimmed back and the servos lowered and SNORT pump below...... and the result is.......

a fit!



Now back to installing the push rods. A tool I used for bending rings for sizing was called a Bow Closing Plier - I used a larger plier all the time, but I had this smaller one with a brass jaw that I never used. However it seemed perfect for this application.

I drew out the layout that I saw David had used. I noticed he had 2 come in over the top of the arm and 2 come in under the arm.

I needed to make a couple of push rods myself and my son gave me a Z bender for the holidays. This plier is so simple it was fun just bending ends with it.

Then using the bow closing plier with brass jaw it was mostly simple getting things bent.



The one push rod that I am not thrilled with is the one connected to the servo in front of the black servo. Here is a short video:
<span style="letter-spacing: 0.0px">

It was an ugly push rod, and I will probably will need to re-do it. However, I will do that once my wFLY TX and Sombra labs RX come in!!!!!!

[He Who Shall Not Be Named]

Trout,

An excellent posting there! Well illustrated, adequate text, and the video was the crowning touch. And you got your photos posted at just the right size for these tired old eyes.

I put my SD pushrods to the second from center hole in the servo bell-crank -- that permits clearance of the pushrod within the cylinder as the servo mount is configured as it arrives. You'll figure that out when you make up the linkage to the fittings kit supplied control surface operating shaft bell-cranks -- their pushrod holes are the same distance from center. Since your servo bell-cranks have more throw than the operating shaft bell-cranks, you'll be over-driving those surfaces right into their stops; your, 'Duh' moment awaits you, sir. Brace yourself.

And I love your showing off of the specialized tools used to give form to the servo pushrods. You a Jeweler? You gotta get that right-angle bend out of that one ugly pushrod pal .... as you observed.

David

[trout]

David,
I hear you and will redo my servos to the second hole (and third?), Thank you for saving me from a duh moment....did I miss that bit of information? (looking at the photo I did)
Yes, I was a jeweler. Sold my business 20 years ago (Tried to save a marriage, did not help) - went to work for the Judicial branch of our Government.
LOL, that pushrod is a really ugly pushrod, one bad turn and it just kept getting uglier from there. David, Is this your setup?

If this is yours, I see that you indeed use the second hole on the port side of your driver and the third hole on the starboard side. Is it safe to guess that your setup going from the top of the picture are.....

[He Who Shall Not Be Named]

Yeah, that's a recent set-up I did, a customer was having problems so he sent it to me to fix.

C is bow plane retract and D is stern planes -- and you want that one in the third hole as you'll need all the throw you can get out of that bell-crank in order to movie the swing-arm enough to fully retract-deploy the bow planes.

David

[trout]

David,
Is there any reason I should not mirror A+B pushrods for C+D? and not do the funky bends that C does? I am getting better at doing these. I got the black servo because its response time was faster and I thought I would use it for the ADF2 for faster responses to pitch. I am going to imagine your response...... it will begin with "Stop over thinking..." So I can just let it stay where it is, or I can rebuild it once more.....we have the technology....

[He Who Shall Not Be Named]

LOL. I've beat you up enough. You now, 'get it'.

Yeah, response time only matters in competitive helicopter and pattern events. Dumb, cheap, non-name-brand ugly servos are just fine for our applications.

Sure, mirror the geometry of the pushrods. I like symmetry!

David

[trout]

You got it! Thank you!

[trout]

I reconfigured the servos on the WTC - will post pictures tonight - and did a quick paint on the sub, not going to do much on detail until after sea trials.

[trout]

Here is the updated crayon drawing of the WTC with the pushrod designations and the way I ran the pushrods.


Please add any comments or suggestions to make this useful to others.