Queen Bee with 09 cylinder / piston

Cox International wrote:Long time ago, somewhere on this forum, there was a thread re. Queen Bee where it was said that they performed so poorly that, when returned to Cox, they arrived back refurbished with a 09 cylinder/piston set. We have been repeating this over the years; until now that is...

Turns out a customer took that advice and bought a used 09 to put the cylinder / piston on his 074. No fit Just wonder where that all originated as the crankpin of the 074 is too small for the 09 conrod.

Someone, I don't know if here or on another forum like RC Groups or RC Universe recently mentioned they did install a .09 cylinder and piston on their .074, but machined a brass press fit sleeve into the .09 connecting rod to fit the smaller .074 crankshaft pin. Found that with the displacement upgrade had a more powerful engine that was worthwhile.

Jason_WI mentioned a crank pin bushing in first post here:

https://www.coxengineforum.com/t6554-cox-queen-bee-09?highlight=Queen+bee+piston

If one could source a sintered bronze bushing and press fit it into the con rod,
that's one challenged completed.

The other is you need to reduce the weight of the .09 piston in order to match
the QB piston weight so the stock flywheel will have enough mass to keep the
vibrations down. You could skin the inside wall of the .09 piston or / and possible
skirt reduction as long as the SPI function is not over done with too much gap.

1/2A Nut wrote:If one could source a sintered bronze bushing and press fit it into the con rod,
that's one challenged completed.

Going back to my college days 37 years ago, I recall that one test of a metal's hardness is the Brinell Hardness Test. They had one in the ME Materials Lab. A calibrated sized special steel ball is forced into the material, dent created and amount of force required and size of dent determines material hardness. According to:

Alubra: Standard Properties of Typical Brass, Bronze, & Aluminum Alloys PDF

C83600 Red Brass (the type that oxidizes / corrodes a copper like red) has a Brinell Hardness of 60. It can be used for bushings.

C93700 Bearing Bronze has a Brinell Hardness of 60 also. It is also used for bushings.

C93200 Tin Bronze has a Brinell Hardness of 65, used for Diesel piston pin bushings.

Back to that other thread Cox Engine Forum Thread# T6554, Cox Queen Bee 09,  Highlight Queen bee piston,

rat9000 on Wed Apr 30, 2014 9:39 am wrote:Jason whats your clearance between pin and bushing if its free to turn, o.k. Theres an old rule to check the clearance,if you have a way to check it.planecrazy bronze will impregnate oil very well,its a tough alloy,but I've seen brass in very old machinery,I'm going back to the 40s,its held up fine,it needs oiled,none of it is turning the rpms these little screamers do,so I'm not sure on the brass.

So, although bronze has a better propensity to have oil impregnated, making it the current material of choice, in years past brass was also used. Perhaps it is this material quality that makes bronze preferred over brass, but we also see in some engines that the connecting rod is unbushed aluminum, our Bees' crankshafts run in unbushed aluminum crankcases.

Since the piston socket area requires a healthy dose of Castor oil in the fuel, perhaps that if one follows suit anyway, the brass will hold up decently too. We're not talking about the bearings on a critical item such as a motor on a heart - lung machine or exhauster for a hospital infectious isolation room or a turbocharger for a real aircraft engine.
No? Just surmising ....

I still never ran the QB .09 conversion so I don’t know the performance. I can get some pictures if needed again since it looks like the pics in the other thread are gone.

Jason_WI wrote:I still never ran the QB .09 conversion so I don’t know the performance. I can get some pictures if needed again since it looks like the pics in the other thread are gone.

I think it worthwhile if you do run it, and would like to see RPM numbers with prop size. I think the brass bearing insert should do well. We all run our Coxes with liberal amounts of Castor in the fuel, and its lack of porosity versus bronze should be of no effect as we've run engines that have unbushed aluminum con rods.
I think you have the engine that the Queen Bee should have been but never was.