hopper theory & practice

[ORLANDO FRETS]

The closer the tank is to the suction source the better the fuel draw.
Obvious.
Today however, with he demand for more power and torque, our venturis are
no longer effective venturi's. The differential pressure is considerably
reduced, (the hole of the venturi is quite large). Put a restricter in the
venturi and no hopper tank required (better fuel draw). Thus the result of
the pen bladder tank, crankcase pressure, baby pacifiers.
The hopper tank works on the principle, once flow is established it
continues to siphon from the pressurized main tank.
Oops, gotta go, hurricane wind warning and tornado warnings coming.
Later 

ORLANDO FRETS
ojfrets at earthlink.net



> [Original Message]
> From: <rcaerobob at cox.net>
> To: <discussion at nsrca.org>
> Date: 8/13/2004 9:23:37 AM
> Subject: Re: Re: hopper theory & practice
>
> I know everyone ignored my first response about this - but I think it
deserves consideration, guys.  The hopper setup probably WORKS simply
because it is closer to the suction source (proximity to the
spraybar/venturi).  Being closer, it is easier for the engine to "draw" the
fuel.
>
> I really don't think there's a lot more to this issue than suction.
>
> Bob P.
> Pump-running-non-suction OS user and ARF flier
> > 
> > From: Brian Young <b.young8070 at sbcglobal.net>
> > Date: 2004/08/13 Fri AM 08:52:12 EDT
> > To: discussion at nsrca.org
> > Subject: Re: hopper theory & practice
> > 
> > Dave I think that your last couple of questions are what occur. If
someone would put one in a hover for a few minutes to setup equilibrium it
should lean once replenishment from the main tank becomes established in
the new orientation, anyone want to try that?  ;)
> >  
> > 
> > ronlock at comcast.net wrote:
> > 
> > Ive been a hopper tank diss-believer for years.  I also wonder why many
continue to report benefits.  What's responsible for the benefit?
> > 
> > I'm in agreement with Nat, and what "I think" Jerry has said regarding
the fuel system with a FULL hopper tank being a column of fluid, and the
hopper would have no benefit.
> > 
> > Maybe hopper serves to eliminate foaming and bubbles?  Do I understand
heli pilots use hoppers for that reason?
> > 
> > In practice do we usually have some air in the hopper?   Or do we
usually have a hopper tank that is flexible?   Might we be drawing from the
hopper without replenishing from the main tank during a vertical?    Then
the hopper gets replenished during level lines?
> > 
> > Still wondering, Ron Lockhart
> > -------------- Original message -------------- 
> > 
> > > >Matt, 
> > > >With or without the hopper tank we still have a solid column of 
> > > >incompressible fluid for gravity and G's to play its tricks on. I 
> > > >contend if it runs ok with the hopper it will run just as well 
> > > >without. Nat 
> > > 
> > > Nat, 
> > > 
> > > While not exactly accurate as stated, your point is well taken. Your 
> > > hypothesis has some merit when the tank is full, but it falls short 
> > > anytime else (which is most of the flight). Adding just a small 
> > > amount of air causes the system to become compressible (just like the 
> > > brakes on your car). 
> > > 
> > > Jerry 
> > > -- 
> > > ___________ 
> > > Jerry Budd 
> > > mailto:jbudd at qnet.com 
> > > ===================================== 
> > > # To be removed from this list, go to
http://www.nsrca.org/discussionA.htm 
> > > and follow the instructions. 
> > > 
> > 
>
> Bob Pastorello, El Reno, OK, USA
> rcaerobob at cox.net
> www.rcaerobats.net
>
> =====================================
> # To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> and follow the instructions.


=====================================
# To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.