Jim Oliver

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Would it be possible to get some "coaching" from those who have experience running Rossi and OS DF engines with props?

I have a NIB RIRE Rossi 90 and RIRE Rossi 65 that I want to use on prop-jet type models; I have experience with other FIRE ABC and FISE ABC engines, but nothing that operate in the rpm range of these.

I need break-in info, fuel, glow plug and prop info-anything you are willing to share.

Thanks,
Jim

lfinney

My Feedback: (44)

i would add all the extra shims that came with the engines, a K&B 1L or HP or like plug..add a couple of ounces of castor to the fuel, you dont have to use the smallest prop though a 12x10 in on the 90, and a 11x7 on the 65, if you run them open face thats fine for the first runs to get a soft needle setting and rpm check, pull plugs to see if they are hammered, if so add another shim.
i add two shims to my 60-65-67 engines and run 11x8 props for run in, the extra oil is just a way to ease the break in
hope you have a good engine test stand, then start running the smaller props and play with pipe lengths..please use earplugs or the equiv.

Pylonracr

The prop depends largely on the airplane. These engines are designed to run in the 20,000 range and need to be propped to run there. If the plane is very clean you can run a carbon fiber 9x10 for very high plane speed (around 175 - 180 or so). If memory serves me correctly the Rossi fan engines were a little short on exhaust timing and ran out of steam around 22,000. I remember raising the timing 5 degrees to get a little more rpm, but in your case I would not do that. Prop it to 19,500 on the ground and fly.
The problem is if your plane is a little draggy. I have a Little Tony with an OS91 fan engine on it. The plane will only go 155 - 160 with this engine because it is a little chunky. Finding a prop to run 20K at 155 mph is proving to be a problem. I bench ran it with an apc 10x9 trimmed to 9 3/4 and boiled in waterfor 5 minutes. It worked, but I am chicken to fly it with that prop.
Be sure to break the engine in at the rpm you are going to fly it at, so try an apc cut down like mine and balanced. Use a littleless prop to get the pm without running it all theway lean. Go to pspec.com and read the break in instructions there, very informative. I bench run for a couple of tanks and then break the prop in a vise so Idon't ever try to use it again. Play with pipe lengths to get the rpm you need.
I can not help much on the smaller fan engine as Ihave never used one. Treat it the same, but it will use less prop. How much less I have no idea.

Good luck and have fun

Scott

bob27s

My Feedback: (19)

Rossi 8 or MC9 plug is a good starting point.

Prop - seriously consider wood to start with. Your best bet is to begin with a good 11x8 or 11x9 prop good strong blade root and hub - then re-work it similar to what we use to do for QM engines. Zinger and Vess are good basis to start with. The last one I made like this was from a top flite 11x9.

Thin the blade slightly, take the diameter down to about 9.5" - 10" inches, sweep the tips. Check the pitch on each blade, and re-balance of course.

If you are planning on using an existing DF pipe, which one? What length is it set at ? It is typically easier to change the prop to match the pipe setting, especially if you are using a welded (non adjustable) jet-type arrangement.

Pylonracr

Not a bad idea on thepropsBob.
I guess this is why you are the engine guy??
I will cut a few for mine and see how they work, since I have been afraid to fly it with anything I have.

Jim Oliver

My Feedback: (1)

I plan to use a std. (non-DF) pipeI do have a Rossi 90 size tuned pipe (not muffled-just the diverging/converging cone type).
I know that one will be loud, so may end up using a muffled pipe.

I actually have two very different Rossi 90 RIRE engines; one is the older style-looks like a huge RIRE 60 or 65. The other is the newer style case (still has bolt on front end) but is much closer to the 60/65 case size and weighs about 8 oz. less than the older engine.

I would guess that the older engine should turn more prop than the newer, smaller case engine. Would that be correct?

Thanks,
Jim

lfinney

My Feedback: (44)

yes, if they have same exhaust timing and if the larger 90 has the large carb, the smaller motor may be a .81,which is a overbored 65..
i own several of the 65-67 engines, look at the edge of the mounting lugs it should be stamped with the actual size hte case may say 61 or 60 in the casting if you post pics i could help a little more, you can use a ducted pipe muffled you may need to cut the adapter and lengthen the overall length for your intended rpm target...

Jim Oliver

My Feedback: (1)

I have no doubts about the engine displacements.

I have two of the .65 RIRE engines (case is same as 60, but stamped 65 on edge of lug, as you mentioned). The big case 90 looks almost identical to the RIRE 65, except much larger overall.

The other .90 may be one of the Byron's Originals engine; the main case is very slightly longer than the 65 case, the difference is visable when the two engines are held side by side.

It would be interesting to be able to document all the variations in the Rossi engines. Even the two RIRE 65s have noticable internal differences.

Jim Oliver

My Feedback: (1)

One thing I noticed, the RIRE Rossi .65s are rear disk induction (I suspect the older RIRE 90 to also be rear disk) but the newer RIRE 90 is rear drum induction.

lfinney

My Feedback: (44)

drums are the thing now better flow and volume, but for what you need you have plenty of potential already the boaters lead the way as they are the biggest user of high output engines of this size

Jim Oliver

My Feedback: (1)

Checked the older R 90; I wuz wrong (Again!), it is drum induction.

Jim