Thoughts on a homemade regulator

Surfer_kris wrote:I have to confess that I don't see any point in adding another fixed restriction in the fuel line. Sounds like you are after a remote needle?

RknRusty wrote:Roddie, rather than filling and resizing, an assortment of tube like this will give you a ton of orifice options.



I have a sack of this stuff which is a mix of brass, aluminum and copper, and it's one of the handiest purchases I have ever made. The smallest will barely accept one strand of .027 leadout wire. In fact last night I used it to crimp my new leadout line to the old leads being replaced and pull it through the wing on my Oriental.

You could try inserting different sizes and see what happens.

http://www.ebay.com/itm/like/291268619718?lpid=82

Shop around, I don't see a lot of copper in that example.
Rusty

JPvelo wrote:You may be on to something Roddie. I can't bladder a reedie without using a fuel filter to step down the line size. Even then any more than 1/2oz floods it whereas I can put a full oz in a tee dee bladder and it runs fine. I may try this.


Jim

Surfer_kris wrote:

pkrankow wrote:Now I want to swage/fuller/neck a piece of brass onto a piece of fine music wire, then extract the wire, and see if the restriction means a bladder can run on a regular needle!

I doubt you'll be able to make that restriction at excactly the right diameter on the first go...
The whole will have to be very tiny, you might as well start with no whole at all and then drill from there until you get it right.

I think the idea is sound, but it would be much better to make the restriction tunable, i.e. to use a fine threaded needle in series with the regular one. This aditional needle could then make the regular needle much less sensitive, and perhaps even obsolete.

So one needle for a coarse adjustment and another for the fine tuning, sounds great.

pkrankow wrote:Don't mess with epoxy, swage it down on a lubricated mandrel!

Phil

Ken Cook wrote:              I'm greatly confused as to the purpose of this experiment. What are you trying to yield here? You will gain no more power nor would you regulate speed doing so. In other words, it either works or it doesn't. The needle valve is the essential piece of the puzzle. Running crank pressure is a pain in the neck . Yes, it works, it also can be more problematic that what it's worth. It doesn't magically give the engine more power, what it does though is that it allows you to run a larger venturi which can be beneficial in generating more power. One thing it can do in addition is allow for the use of the stock needle assembly. Realize something here, if it was good to use, it would still be in use today. Very few that I know of use crank case pressure in control line aside from the vintage combat crowd.  The vintage stuff uses it due to the engine arrangement and tanks. My engine for instance came with the backplate already tapped for pressure. I've gone and soldered some of the fittings back up and used either bladder or suction.

I sometimes feel the need to use a retrictor in my fuel line due to the bladders I use. Temperature is a critical factor in bladder use. I use a natural latex with little pressure in the hot summer, in the winter however I need to use the highest thickest wall bladders I can use. The wall thickness is 1/8" and these are being used for 1/2A. Again, you use it if you need it. Installing a restrictor just to use a stock needle may work if that's your goal, but your not going to benefit from using it. The threads are too coarse and generally the taper of the needle isn't very good. This is the problem with the remote needles that are offered on the OS LA series engines.As soon as the engine starts to lean, it falls on it's face due to fuel starvation .  Even though the needles are o-ring sealed allowing for high pressure use like a bladder, you don't get the finite adjustment that you would receive from a high quality replacement.