Hi Brett and Randy,

Will these three engines interchange??? If the mounting holes are the same, how about the length of the shaft? I wouldn't think they would be the same but I've noticed some use the Ro Jett 61 and then install the OS 40 VF?? I appreciate your input.
Thank You
Gary

  I don't have an FSR. The vf and RO-Jett are close enough to use the same mounting holes. The VF has a little bit longer nose, but it's not dramatically different. The biggest difference is the position of the needle valve - the VF is about 1/4" further forward and a little closer to the mounts. Mine is set up to run the PA, RO-Jett, or VF.

    I would also note that all the VFs are the same. I had one that was about 1/16 shorter from the holes to the thrust washer plane.

     Brett

Thank you, I was going to install the FSR in the SV-11, cause Dub told us it going to be a while before he can get the engine done. If different in mounting better just sit and wait. I'm sure it will be worth the wait. In the mean time I'll just keep playing with the FSR. I have to get bye the shop and make up a header that will allow me to install the pipe in the fuse. Being its a old set up no one has the type header I need. This is the bad part about fooling with old type set ups. Its worth the trouble if you know before you start that you may have to make something yourself. If the Ro Jett 61, Brett's style, is anything like my FSR, I know I'll be in love. I have enough faith in the FSR that I'm going to build a plane just for her. Probably a Stiletto Wing, styled more like the Stilomag. My wife going to kill me, she says why don't you build some of these kits instead of making something different?? Just me, Gary

Is the Ro-Jett a barstock rear ex. or cast case rear exhaust?

Hi Gordon,
Its a BSE the same one Mr. Brett Buck designed. Its very pretty and runs very well. When I received the packing slip it stated its a Brett Version. I figure Dub Jett listened to Mr. Brett Buck and made a very great running stunt engine. If ya talk to Mr. Jett he'll just laugh and say oh another one of you guys that want to run a stunt engine. I believe all of Mr. Jett's engine are great and I really like the Brett version.

   To be entirely clear, I absolutely *did not* design the engine. I saw Jim Tichy's engine run, and ordered one the same night. I just used what they sent me. The story on how it came to be is fairly well-known. They had intended to reduce the exhaust duration from 140 degree to 136, but added instead of subtracted when setting the tool depth, and wound up with 144 degrees instead. That was the version that Jim and I had. I made a few tweaks to the intake and suggested the "long" intake with the small dribble hole, but otherwise, just put it in there and ran it. Subsequently, the "mistake" was discovered and corrected, leading to the current "standard" engine with 136 degrees exhaust duration. I very much prefer the 144 degree version, which people have been referring to as the "Brett" version, because it runs a lot like a gigantic 46VF. The 136 degree version is much more of a low-rev lugger with a pretty strong break, and wants to have larger diameter props.

     My two contributions were some experiments that led to a pretty solid setup information, and that I did a pretty fair bit to show that it was a viable and competitive engine. I also did some compression ratio testing with head buttons graciously supplied by Richard and Dub, with ambiguous results.

     But I did not design it.

     Brett

Btw

OS 46 VF-P 1.55hp 12.91 ozs
OS 46 VF     1.35hp 12.76 ozs

That is with the RC carb installed, subtract around an ounce for CL weight.

P is for Pylon. 

Hi guys,
I've started using the Ro Jett 61 (Brett Version) and believe me there isn't anything better. I don't have everything completely set up. I'm using the wrong prop for one thing (12/4 APC Two Blade), I've installed a 8 ounce tank in the SV-11, using around 6.5 ounces. Launching at 11,130 RPM'S. I have about a 15' smoke trail and the engine is making a real nice break when ya pull the nose up. At the moment lap time is 5.3 second laps on 62' lines. The SV-11 weights out at 61-62 ounces. I have a few trim issues and I believe she'll  be my baby for the few contests I plan on attending. After I take care of the few trim issues I have I'll try the 12 x 4.25 three blade and maybe a few different flying handles. So far its great!!

Gary

The P pylon model came out in 1987, and was fitted with a crankcase pressure fuel pump, which accounts for the additional weight, don't know if the internals are different as both claim 16,000 rpm for the hp numbers. Pylon version photo below.

P is for "pumped" in this case, not pylon. This engine had a larger carb intake than the non pumped model, and "theoretically" should be able to produce more power.  A comparison of part numbers for the two versions would reveal similarities and differences. I would think that if anything, the crank and cylinder may be different, and of course the carb.