Good afternoon, 

I have a Shark 402, just about assembled by my brother Ron. It will be pulled by an LA-25 converted to C/L.  However, I am struggling to find tank room on the inside.  I am hoping to use a Hays 4 oz. tank.  Just not enough room inside.  I have had good success with mounting tanks inside.  However, I usually run the engine feed tube through the fuselage behind the engine and then to the spray bar.  I put the hole on a plane to the middle of the venturi. But that will be a squeeze. 

I probably would have to angle the tube slightly backwards for clearance.  Is that alright?

I could also run it through the fuselage to the front of the engine.

What are your experiences with this?  What advice do you have for me?

I don't know how to share a photo from Google photos or I would.

Thanks ahead of time.

With my FP 25, I am only getting about 5 minutes with 3 oz.  Also with an older O.S. 25, about the same.  I would like to have a 7 to 8 minute run.

I too am hoping we get some general discussion here about mounting a tank on the inside of a profile model. It seems a bit unorthodox, but it has its adherents. I've got in mind an inside mount for a SIG Skyray powered by a Saito 30 4S. No idea how this would work out.

Dave Mo...

You can see details of one way to set up an inboard tank on The Dirt's Cheater Slow article in Model Aviation. It has a couple of good photos and some description of the hows and whys. This was for a 4 flowing ozzies Pylon brand feeding a Fox or ST engine. You can see he just ran the feed line under the fuse and straight to the needle valve. He did have a filter and a bracket to support things and keep them out of the prop.

Just access the Model Aviation archives and search on Cheater Slow. May 1977 issue, page 24.


The Divot

  Mr Schafer I just sent you a P/M...

SEEING you brought it up ! , 

On the Phantom , the tank uniflow vent was inboard , 1/8 plumbers copper , about 1/16 th bore , cut off at 45 or so degrees .

As it stuck out 3/4 or so , one day a pliered it round forward 1/8 off the side , so 5/8 or so longitudeinal . After previous flights that day . !

Straight Off , had to wind in 1/4 turn at about 2 1/2 turns on a Taipan N V A , for same air setting . Gave up after a few flights and back
to straight out , and satisfactory . Verily .
Its one flaw was nerwe duggga dugga , when a fair breeze was steady , rich & lean into and out of wind , level laps .
notta Lotta differance from that once the nose was turned though , clawed away meritously through hail & storm .
Well Storm anyway , the odd damp day , tree , dogfight with seagull and various misadventures ,

Mayve been to wind sensitive with the vent straight into the airstream , so thered be a few variables there to experiment trough , perhaps .

 

Today, I did my first two flights with this 402.  As I said, the Hayes 4 oz. tank is mounted inboard and the tube goes through the Engine mount area in front of the engine and to the NVA which has the pickup end pointed down.  So far, so good.  As noted somewhere here above, I did need to lean it out very lean and due the the fuel being being a bit pressurized from outside from movement toward the outside, it settled in to a very nice run (LA 25).  I one short flight where it was running too rich and once in the air, it became richer and died.

I have a different issue before I can do stunts.  It is tail heavy.  For the second flight a rubber banded a large bolt on the front and the controls were still squirrely.  Oh, the fun, of trimming!