Thought I would separate this from the model's thread.

I made .004, .006 and .008 restrictors.  Just a 1/2" length of aluminum tube, scored around the ends for better hose retention and swaged in the middle over the appropriate size wire.  These can be inserted into the pressure line and exchanged for experimental purposes.

I tried running the setup this morning and was getting a run on the .004, but the engine was vibrating.  I changed the prop to get one in better balance.  I also wanted to try the .006 restrictor.

At that point, I couldn't get the engine to do more than run the prime.  HMMM!  Turns out that the tap in the crankcase had come out!  JB Weld next time. 

The little restrictors I mentioned work just fine on the AP Wasp.  I haven't gotten back to the reed valve engines, but will when I get the Blackhawk Bullet done, as that is the power source I plan for the model.

Got some runs in today and an actual flight.  Not there yet by a long-shot, but there is some hope.  I tried the .004, .006 and .008 restrictors, with the performance and stability improving as I went larger.  I'll make .010 and .012 size for future tests.  With the smallest orofice, I couldn't get fuel draw enough to run at all.  The .006 would surge at first then go lean, open the needle and recover, but surge and go lean again.  Never did hit a happy setting.  The .008 seemed stable enough to try a flight, but it again didn't prove stable enough for stunting and would do outsides OK, but died on insides. 

More as I learn....

I picked up a tip from...someone, can't remember now who or where, of using threaded inserts for restrictors:  I cut about 3/16" length of 2-56 threads and worked it up inside the fuel line...air follows the threads around for pressure but fuel, coming the other way, tends not to make it; sort of a semi-one way valve.  Pressure can be adjusted by the length of the threaded portion. Have installed one but haven't run it as yet; does seem to work as advertised.

I got a decent run on the engine yesterday!!     It looks like the .010 restrictor is about right.  The needle is touchy, but that is no surprise.  Also, I was running 10% nitro fuel, as I had forgotten to fill up on higher powered stuff.  Now for flight testing.

Both locations seem to work, no problems with blowing out since I am using JB weld.

I still am not able to get a good run in the air.  If anyone else is working on this, I would love to hear how you are doing.

I now understand the problem here! However I don't know how to fix the problem. 

I was explaining to a friend how the reed valve works the other night and I see exactly how this fits together with thiis problem.
When the piston goes up it creates a vacuum in the crank case which unseals the reed valve and sucks the fuel air mixture into to the crank case. It needs all of this vacuum and the volume as well to get enough of this in there.
When the piston goes down it creates pressure in the crank case which seals the reed valve and forces the fuel air mixture past the piston via the cylinder port/s. It needs all this pressure and volume to achieve this properly it seems.  This last statement very well may not be true for the Tee Dees can run using crank case pressure and do so successfully. More on this in a moment.

By 'stealing' some of this pressure the reed may not seal completely nor deliver its full volume of fuel air mixture into the cylinder as it should.
Attached is a picture of a Cox twin cylinder that can never be made to run because it will never create any vacuum in it's crank case so long as the pistons are alternating. On the other hand, if the pistons were to made to fire at the same time and down stroke at the same time, there would be vacuum in the crank case as it should have

When you tap a Tee Dee engine, the difference is this seal is made by the crank shaft! As for the volume, I mentioned before, this doesn't seem to hurt a tapped Tee Dee in the least so I think the problem is in the reed/seal department.

Larry, the RR1 is rather a valuable engine and I have always wanted one but have not been able to afford one. Do you think the rotor seal in this engine would work better? I think so.

Robert

The problem I am having is not to get the engine to run, it is to get it to run through a full tank without having to fiddle with the needle valve.  It runs great when it runs.  The restrictor is used to prevent generating so much pressure in the tank that the needle is too sensitive.  Also, you don't want any back flow of the pressure when the crankcase is at negative pressure while drawing fuel and air.  Since the net pressure in the case is positive over the cycle (gotta be, or you would never deliver fuel to the cylinder) the key is to smooth out the cycle.  Thus a restrictor.  I will try a check valve.