Miss RJ
Hey Beau,
I ordered the plan and article in German when I was living there a few years ago. I’m sure you will agree with me that this is a project not to be undertaken lightly or without a great deal of thought as to how the various installations of equipment are to be done, once you get the plans and have a bit of a look.
However, having an OPS 40 new in box, I relegated this plane to a “must have” status and have been giving it some quite serious thought for more than just a while now.
The main question remaining for me is to mount the engine inverted or sidewinder. Here are some thoughts.
If inverted, I will have to fabricate a new angled header as the OPS only has a straight exhaust stub. In this case I would use the MACS unmuffled 7.5 pipe as it is about the only possibility which will fit in regard to length and ground clearance. With this arrangement, I think that a two-tank fuel system is required for sport flying as there is insufficient space above the cooling- pipe duct for a large enough tank. I am thinking a two ounce header tank above the pipe duct and another 6-8 ounce tank in the fuselage above the wing might be reasonable. If I had the MVVS GRRT, I would definitely do it this way.
As I am not proposing to build an all out F3D machine (Miss RJ is more than 15 years obsolete and hopelessly outclassed anyway), I am becoming more and more attracted by the idea of side mounting the engine. This way, you can move the thrust line up by about 1 or 1 ¼ inches for better propeller clearance and all the hassles of an inverted mount go away too. The fuselage needs to be relieved on the one side and then any length pipe can be used, being half buried in the fuselage side. If I do it this way (and I probably will) I will mount the engine using an aluminum mount directly to the firewall and do away with the beam mounts shown in the plan. A bigger tank can also be fitted directly behind the firewall in this version. I will probably use a muffled pipe with this version.
I have also scaled this plan down to 75% and think that this size is perfect for 15-21 size engines. I have a front intake, rear exhaust Uctkam 2.5 with matching pipe (a Russian Rossi 15 copy) begging for a home. Other contenders are the rear intake rear exhaust MVVS 15 or even an MVVS 21 which I have lying idle.
So, there are some thoughts as to what I will do real soon now. I’ve managed to enthuse myself again and might even make this my next project.