I already posted this in the Q&A but it is not getting many hits. Since the folks here have always been so helpful in the past, I'm going to try:

I've just completed the testing of my first smoke system on an Aviation Models, (SD/TOC Extreme) 33% Yak 54 with a 3W 70cc engine. It has the wrap-around pitts style muffler with smoke fitting already attached.

I am finding that smoke is coming out ALL the time in small amounts, with a noticeable difference when I activate the Sullivan Sky Writer pump, (on 6V). Obviously, this burns up the smoke oil pretty quickly, and it also seems to occasionally cause the engine to take some oil into the cylinder, making it very difficult to start for awhile, (had to flood it, open up the throttle, flip repeatedly, ignition on, flip, repeat, etc.).

Another issue I ran into is that the pump seems to work for a little while and then stop. It will start again if I adjust the end point up and then back down to where I want it. I have it at a pretty low setting so the oil doesn't get used up too quickly. It worked fine when I had it on at about 50%, sending huge clouds of smoke out, but that was more than I needed and it lasted about 30 seconds.

Any ideas all ye 3D smoke gurus?

-Pat

I'm suspecting both of these issues are in the programming.

The issue of smoke being on all the time is likely one of where the "0 level" if you will. Remember, the skywriter thinks like a servo, but it needs LESS than 0 to register "off"...-15% to -140% are treated as "off". Of course, like any servo, what our RADIOS say is "-15%" may be an entirely different value to the servo. My suggestion here would simply be to dial that off value down as far as it will go using, probably, an Endpoint setting.

As for the system not coming on at times, my GUESS (and it's just that) would be that you're not overriding the pump's built in failsafe. The pump must see a value in the "off" range (-140 to -15) for 5 seconds when powered on before it will activate. Perhaps your system is either not consistently seeing this value, or not seeing it long enough. If your low end is not reaching that range (as evidenced by smoke never going off) then it may certainly not be reaching it long enough, consistently, to always activate the system. The best solution here is to set the subtrim value for the radio to its max negative value.

Finally, keep in mind that any discussion of + or - here is from the PUMP'S point of view...again, like any "servo", it may be reversed from what the radio thinks, so all these values may need to be opposite, e.g. +140 instead of -140, in your particular system.

Here's Sullivan's setup guide with the info above in more detail : http://www.sullivanproducts.com/S753...rogramming.pdf

HTH

Yep. I tried all that already. Not really sure what's going on with it. I did put the high end point up a little bit and that resolved the issue of it not starting up again after running it, and now the smoke is super thick, which is fine.

Any other ideas?

*hrmmm*

Beyond the above, no, not really. In my somewhat limited experience with the Skywriter, the steps above have resolved both issues you mention.

Sorry i couldn't be of more help.

What voltage are you running. I've found that the Sullivan likes 6 to 8 volts. I run a fully charged 6v nimh, which is about 6.7vdc and it runs better than using a 4.8vdc nicad. My first couple pumps would loose prime after a few short runs. I sent them into Sullivan and when I got them back, they worked perfect. I think the pumps need to be broke in so if you run the crap out of it for an hour or so, it might help. Just make sure its pumping fluid the whole time so it doesn't burn up.

I do recall hearing something about the break-in period, so maybe things will seal up and it won't leak small amounts when it's turned off after that point.

It's on a 6V NiMh pack, and it's too much power! I really have to dial it down in order to keep it from running the whole tank dry in 30 seconds.