[nitronutz]

Originally Posted by Pauld

I would balance for CG with the tanks at least 1/2 full and then pump them out and check the CG change from there. The Flash will get "cobraish" on landing if the CG is too far back.

I would also cut the intake duct off at an angle facing towards the sides of the plane so there is a way for the air to get around the tanks.

Looks like fun dude. I managed to squeeze an 80 ish oz tank into the new Boomer Torus I am building so I can run lots of smoke. A little concerned about CG change as well as it's about 6" ahead of the CG. I am planning on starting small and working up 20 oz at a time.

PaulD

Ya Paul I will do a little trimming to the ducts, I think that will put me where I need to be.

Yep it is fun I just can't wait to get back in the air with this thing, I only got 5 flights last summer with her. As for the tanks I will see how this sets up and than go from there as I know I can go to 24's but that is not a very big jump.

[nitronutz]

I know the reasoning behind it with interference, but I really cannot escape placing the smoke pump anywhere in my flash that is 6" or more from any servo wires or batt or fuel pump etc....
I would like to place it down where the two inlets join but my servo wires from the wing come through there.............. any suggestions??

Here are a couple of pics of my options.....

[nitronutz]

Here is the pump in between the tanks right on the CG.

[akb]

I think it is good to keep a much distance as you can, but if you are running 2.4, I don't think it is as critical as it was with 72 mhz. Correct me if I am wrong. I thought that was always a big selling feature of 2.4. If you running 72mhz I would try very hard to keep the 6".

Alan

[nitronutz]

Alan I am running 2.4, I somewhat understand the 2.4 system and this is good info if your correct.

[nitronutz]

Another quick question.... in the manual it say to splice into your ECU batt for power, is this something thats become a no-no or is it fine, because it sure would be great if I didn't have to add the weight of another batt.

[Wayne22]

It looks like with those tanks almost totally blocking the air intake that your Wren will be gasping for air..
Are you using the wing tank? If not, there is a nice place to put a tank, though not necessarily the 24 oz ones.....

You can tap into the ECU battery with a Great Planes deans series or parallel adapter (Depending on the configuration of your plugs)....one thing though, it you get a piece of crud in your pump, or break a gear tooth, the pump may stall and suck the ECU battery down (it has happened... )

[JimBrown]

Wayne,

You'd be surprised at how small the intakes can be when dealing with a turbine.

With the old Ducted Fans, intake size and shape was critical to getting maximum airflow and thrust. With turbines, intake size and shape is not really critical at all, to a certain point. As long as the turbine can get enough air, it's good. And it does not take much of an opening to allow enough air to get to the turbine.

Of course, rigorous testing of a setup is always a good idea.

Regards,
...jim

[nitronutz]

Well I have it all in, I did make more room in the intake ducting, I pretty much got the tanks on CG but I put the smoke pump ahead of the CG so hopefully when I do my CG checks they will take no or little adjustment. I will be using power from my ECU batt, here are a few pics. Thanks for the input guys

[Pauld]

Nice job Paul.

I'm sure it'll be.......SMOOOOAKIN!

PaulD