News:



  • June 22, 2025, 03:16:31 PM

Login with username, password and session length

Author Topic: Can a tank be too large?  (Read 1208 times)

Offline frank mccune

  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1627
Can a tank be too large?
« on: October 16, 2013, 05:24:53 PM »
     Hi All:

     I have been having problems with the tank set up on my Fox.25 profile stunt trainer.

     The problem is that after I set the engine to run a great 4 cycle on the ground it leans out to a screaming 2 cycle in the air that results in a very hot run. The engine is fried when it finally lands!  Thanks to a large proportion of Castor Oil in my fuel , the circa 1953 Fox still has a bit of compression.

    The tank is 2.5" long,1.5" tall and 2.375 widr.  The distance to the fuel pickup crease in the tank is 2" from the nva.  Is this too far to draw fuel? There are no leaks in the system or fuel foaming as far as I know. Is this tank, four oz.. too large for this application?

    I need to ask about the profile tanks that Veco and Duke  Fox sold at one time.  These tanks were designed to used on profile planes but I have been told that they will not work! They look good but what do I know?  The Veco box call it a T series tank.  Pehaps I should convert these tanks to a Uniflwow system to see if they work.  Any thoughts about these tanks?

    I am having the same problems with a Midwest Me 109 profile stunter with a 5 ounce wedge tank and an O.S. .35 Stunt.  I converted the tank to uniflow but that seemed to make the problem worse.  Any thoughts about this prblem?

    Perhaps it is past time for me get new tanks! Lol Hello Brodak!!

    Thanks for any input that you may have concerning my tank problems.

                                                                                                        Stay well,

                                                                                                        Frank
    Ps.
    This tank on the Fox .25 worked very well on a slow combat plane in the 80's. It is a suction tank.

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 14476
Re: Can a tank be too large?
« Reply #1 on: October 16, 2013, 06:34:32 PM »
    The tank is 2.5" long,1.5" tall and 2.375 widr.  The distance to the fuel pickup crease in the tank is 2" from the nva.  Is this too far to draw fuel?

   That sounds like a good guess. It's still drawing fuel, but the pressure drops as you build up speed, and the faster it goes, the leaner it gets.

    Brett

Offline Chris Wilson

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 1710
Re: Can a tank be too large?
« Reply #2 on: October 16, 2013, 09:14:31 PM »
Place the tank inboard?
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Balsa Butcher

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2356
  • High Desert Flier
Re: Can a tank be too large?
« Reply #3 on: October 16, 2013, 09:19:32 PM »
Get a Brodak or RSM modern uniflow tank. Yes, both tanks are too large. You will probably only need a 2.5 ounce tank for the 25, 3.5 ounce for the 35 S. They are very thrifty. Try some bench runs to confirm.  8) 
Pete Cunha
Sacramento CA.
AMA 57499

Offline frank mccune

  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1627
Re: Can a tank be too large?
« Reply #4 on: October 17, 2013, 05:36:55 AM »
   Hi Guys:

   Thanks for the replies! "I needed that!" Lol

                                                      Frank

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 14476
Re: Can a tank be too large?
« Reply #5 on: October 17, 2013, 10:19:18 AM »
   Hi Guys:

   Thanks for the replies! "I needed that!" Lol

                                                      Frank

   It's not too large so much as it is too wide. Try a Sullivan clunk tank with the flat side up against the fuselage.

   The 20FP needs a relatively narrow tank on a conventional profile mount. A typical Veco wedge tank will not work.

     Brett

Offline Tim Wescott

  • 25 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 12899
Re: Can a tank be too large?
« Reply #6 on: October 17, 2013, 12:03:35 PM »
The LA 40 that I have has the same problem -- I had a wide metal tank on the plane, and had to launch blubbery rich so that when the plane leaned out it was about right.

I changed to a Sullivan clunk as Brett describes (but with a uniflow, just because).  The plane runs roughly the same on the ground as it does in the air, I can adjust the needle by RPM instead of by listening to the nature of the blubbery richness, life is good.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.


Advertise Here
Tags: