I will probably repost this on my King Tiger Build Thread - but I thought a lot of tankers using the DB2/3 system might be interested in this (if it hasn't already been done).

WHAT IT IS: It's pretty simple; by using my Spectrum TX I was able to MIX in ACC2 and slave it to the throttle. I removed the cam operated motor that controls the elevation and built a cannon barrel mount to the floor of the turret. With the barrel re-positioned, I added a servo that was connected back to ACC2.

For me, this has been the most hated part of the Heng Long system and hence the DB2/3 system. The cam operated elevation always upset me. Plus, I was able to extend the up and down position of the elevation for those pesky Shermans that hide up on the hill.

Here's some pictures:

Again, Here's some pictures......

More pictures of the installation:

Please see video for actual operation (I'll be adding another lower link from the servo to the elevation wheel to beef up the linkage)
http://youtu.be/DHPBxIjJXmM

I should have explained that it is hooked to a different RX for the test. I'll connect it to my RX in the KT this weekend.
tjs

Nice setup. Having to wait for the dumb cam to recycle to elevate/depress the gun has always been a PITA. This seems to provide immediate control.

That is very interesting. However, doesn't the cannon always want to return to neutral when you let go of the stick?

Good morning (5:30 am - time to walk the dog....).
I don't have a spring on my throttle for nuetral return. I downloaded the TBS software and will configure the recoil trigger this weekend. I did just have a nasty thought - (ughh), when I fire the cannon by the throttle stick, it will change the elevation of the gun. I need to fire the cannon by using a different button, operation.
Maybe this won't work...

You could wire a button across the potentiometer to fire the cannon. I have done this on my DX6I. Not sure how the servo would react to this though.

A good morning walk/work out clears the head. First - I can't believe I missed it and second - how stupid was that?
Third - the fix.
I'll run the ACC2 on the RX to the "throttle in" for the DB3/TBS etc. On the TX, I'll modify the endpoints on a three way rocker switch where UP is Fire Cannon, MIDDLE is neutral, and DOWN is Machinge gun. When I flip switch up, cannon fires and down, machine gun fires. Ceneter position neutral.
I'll then run the THROTTLE on the RX straight to the servo that is connected to the gun elevation.

Do you see any problems with this setup and the DB3/TBS?

If it will work, it absolutely TRUMPS the Clarke board (for me) as the cam style elevation ruins the thrill of the shot. Perhaps, because I've been an active bird hunter in my youth and enjoy target practice to this day, I equate the proper aiming of a weapon with firing that weapon. The cam style elevation is like jumping on the Merry Go Round and waiting for it to go round and round and hope it ends up with where you want to shoot.

With this setup (full elevation control, proper recoil, programmable sound and with the optional amplifier to really get things rocking) and the price drop on the DB3, this would be the system of choice for me. It does require a programmable TX (which I like as I just switch which model I'm controlling - I have 20 model memory function including helicopters). It will also allow one complete unit that can easily be switched between models and reprogrammed quickly.

Now if the TBS has a memory module like my TX where you could simply switch the model sound - that would seal the deal.

Thanks,
tjs

I would like to see a wiring diagram of this if you could. I would like to post this on my website as a fix for the elevation. Full credit to you of course.

Thanks. This cam elevation has always bugged me. However with the shotgun approach to the IR beam, accurate aiming is not that crucial so this has alway been just an annoyance to me.

Thanks for the fix.

One thing I did find out though. Paralleling a servo with the DBC gives you an automatic recoil servo.. With the switch wired across potentiometer, the gun fires and the servo recoils. This added to what you have down with the elevation sure is helpful for function. It gives guys a couple of options for recoil control.

HI Dan,
I'm feeling dense. How is a potentiometer wired in with a parallel servo?
After I hook up and thoroughly test the elevation and ACC2 on a rocker switch, I'll draft a diagram and some pictures for you. Happy to help. I believe it will give you a good edge over the Clarke board for people looking for a true elevation/recoil solution with custom sound.
tjs

If you take the board out of the servo then you dont need to worry about it returning it to center. Then you simply have a gear motor. works very well.

I think I saw that on "Hack of the Day" or some such site. I've been meaning to play with it. Looks really interesting with alot of applicability.
Are you using the "motor servo" for turret rotation or elevation?
tjs

That is true when used with an RX 18, but through a regular receiver without the board, I believe the servo motor just runs continously if you tried this.. I put the voltmeter to my receiver routputs and there is power being feed to the servo motor all the time.

You wire a switch across the potentiometer. When you activate the switch it has the same effect as full deflection on the stick. An addtional Servo is connected in parallel with the DBC channel that controls the cannon shot. When you push the button the cannon fires, and the additonal servo on the same channel gives you full deflection back and forth. The servo recoil was under my nose the whole time. Recent testing comfims that this work fine.

So all you need to have servo recoil on a DBC3 is to tie in a servo with a splitter cable to the same channel on your receiver that fires the cannon. However you still have the fire at will with the IR shot only firing based on DBC timing.

The Benedini option I talked about earlier for firing a recoil mechanism will still be my first choice as it gets rid of the false recoils.

No it doesnt .When you let go of the lever it cuts power to the servo motor and it stays inplace.

Panther G is correct remove the board from servo solder two wires to the motor then it be comes a gear head motor servo I use one on the turret ring mech that www.35rctank.com made for me .
Here is how to do it .
http://www.tedpavlic.com/post_servo.php

Jimmy

I wonder how the motor does not run when my receiver is feeding a constant voltage supply to the motor? I checked this with my voltmeter and on the servo outputs there is a constant supply voltage?

I have pulled circuit boards out of servos for years, and used them as gear motors, but that is a much different application then we are talking about here.

Maybe I am missing something . So just to be clear you have pulled the electronics out of the servo, reconnected the motor, plugged it back into the receiver and it operates the same except it doesn't return to neutral when you let go of the stick?

Interesting. I'll have to try this tomorrow.

Cheers

IT WORKS!
IT'S ALIVE!

I finally have my Spectrum programmed with Dan's BD3/TBS to provide full elevation control using the throttle stick and by using the three way toggle switch on my TX for "FLAPS".

The toggle switch allows nuetral (no sound), flip up once for machine gun and next notch for cannon fire.

With the inertia and awsome programmable Benedini TBS sounds with recoil slaved to the cannon fire through the TBS, this system is EXCELLENT.

I'll finish buttoning up, wiring the turret, etc and I'll draw a wiring diagram for the programming for Dan.

tjs

Great to hear. I'll look forward to that wiring diagram.

It is also good to have someone but me talk about the sound quality of the Benedini.

Cheers