New to control line

Need some advice, very new to control line. I have a OS40SF and an old Super Tiger G21. Both motors have rings and were R/C. I had venturas (?)made for both of them and new needle valves installed. Can these engines be used for stunt and be made to run 4-2 break? What type of mods have to be done, or is it even worth it? Both engines are new and never run, not even to break them in. I also have a OS40FP that is well broke in but still set up for R/C. Due to my limited budget, I would like to use these engines for control line if it is at all feasable.

I know that the Fp 40 with a proper OS venturi and needle and a APC 11-4 or 11-5 on sig 10% champion fuel with an extra 4 oz of castor to the gallon and a OS #8 plug works just great.I also use a 4oz uniflow tank.

LAST EDITED ON Aug-11-02 AT 10:38 PM (CDT)

Two of the G21 series engines were used for CL stunt running a classic 4-2-4, but only one of those (AFAIK) was ringed. That was the 46, which produces one of the nicest classic engine runs known, with a particularly attractive unmuffled exhaust note. The CL and RC versions were exactly the same, other than the intake.

The other G21, a baffle piston 40, was produced in very low numbers, and TTBOMK, had a lapped piston, not ringed. It was replaced by a high performance flat top piston version that was a very poor choice for trying to run a classic style stunt run.

The OS SF 40 was the interim model BB engine between the FSR and the current FX. It was sold in a CL version, with a plain venturi, but it also is a higher performance type, similar to what the majority of G21-40's were, and has to be operated in a regime called the high rpm, low pitch prop mode. Let it rev, and control flight speed with flat pitched props.

A couple of decades and a half ago, I tried to run an ST 40 in the classic manner, totally unsuccessfully. Then about ten years after that, (roughly contemporarily with OS's FSR's) I tried to tame the early model FP 40, and finally gave up when I found rather few 11-4's and 12-4's to work with, and absolutely no "3 inch" pitch props at all.

Today, that model is off the market, but has been a lot more popular in CL than any OS "SF" engines. I acquired another FP 40, but so far, I'm not encouraged to repeat my past experiments now that various low-production carbon props are being used for the high rpm mode, given that there is a truly huge expense in using those propellors.

Kiwi

Smitty,

The OS SF isn't probably a great choice unless worked on quite a bit. It's really a high performance RC engine and it's pretty heavy. If the ST G-21 you have is a 46, you're in business. That is one sweet motor, if put in a relatively light plane. The OS FP 40 is a nice running engine, particularly if you block the by-pass port and put in a couple of head gaskets. But even stock, it pretty decent.

What do you plan to put the engines in?

Haven't decided what the motors will go into yet. I am flying a Sig Banshee now with a tower 40 in it. You are right, the OS40sf is pretty heavy. The G21 is a 40 that is ringed, but it looks like half the mass of the OS.

Smitty: I would go with Max1998's advice. Use the 40 FP with an OS venturi and a low pitch APC prop. Easy to start, easy to use.

Thanks for the input. I started the 40fp today and it hasn't been run in two years or so and started on first flip. I will go ahead and use it and try to find someone into R/C that might want to trade a 40FP for the 40SF. Can I order a venturi and NV assy. and head gaskets from OS for the 40FP?

>I will go ahead and use it
>and try to find someone
>into R/C that might want
>to trade a 40FP for
>the 40SF. Can I order
>a venturi and NV assy.
>and head gaskets from OS
>for the 40FP?

The 40SF is worth more than the 40FP if they are equals (new for new or good used for good used)

I have venturis, head gaskets, and needle assemblies for the FP if you need them.