Hi guys,
Mr. Bill was asking if the older OS Pipe Type engines was worth giving a try to see if running pipe would be the answer for some that didn't want to spend a million dollars. I can really say that my OS Max 40 FSR/ABC on Pipe is great. I have a few of the OS Max 46 SF/ABC engines that I purchased back in the eighties. Not knowing better I ran them using a muffler and had great success. I would run my ST 60 for a while than switch to the OS 46 SF/ABC and couldn't really tell which one had more power?? Now that I have a pipe set up that I purchased off of e-bay, cheap, I can give the OS 46 SF/ABC a try on pipe. The 46 has two sets of holes for muffler or pipe, found out that the inter set will accept the FSR Header. The bolt pattern is the same on the 40 and the 46 but the 46 is a little wider, has a bigger head but seems like the prop will end up at the same location. I'm going to start with a 12/5 prop and I believe that will be close. I'm going to use the same pipe distance and change from there. The 46 weighs a little more but I believe it will make a lot more power. The only way I know to test the power is bye using a fish scale to see how much she will pull. I don't remember how much my OS 40 FSR was pulling, so I'll have to hook her up and check one against the other. I was looking to buy one of the OS 46 VF but I believe I'll have a better set up with what I have. The worst part will be is that I'll have to make my own header if I want to Tailor the pipe inside the fuse. Could set up a degree on the engine and do it that way but the plane is already build??? I'm really having fun playing with the different engine and finding that they work just great and ya don't have to spend the million bucks to have fun. Let ya know how it turns out, Gary

Hello Gary,
  I am not sure if hooking up the planes to a spring balance will give you a measure of how much power the engines are putting out. I have always thought that if the engine is stationary then the prop is stalled. Not sure you will get the right answers going this route. Need an aerodynamacist to chime in here!

Regards,

Andrew.

Hi guys,

Thanks for the information. I bought the OS Max 46 SF new as a C/L Stunt engine from Tower in the eighties. I'm not sure that using the fish scale will give me the power that the engine is putting out but I can compare each engine by using this method. I believe the stock venturie is around .310, as I remember the engine came with two venturie's and a few extra head gaskets. I ran her yesterday and did well but I want to make a few changes. I had the old stock needle valve set up in her, its has to many chances for air leaks, so I've changed it to one of Randy's set up's. I need to install a new glow plug, the one recommended by Randy. I believe the pipe length I was using is to long (21"). I'm going to change it to 18.75. She wanted to run around 11,200 the same as the OS 40 FSR, she seems to have more power than the 40 FSR. I'm going to go burn a few circles with the FSR today so won't get a chance to play with the 46 SF until tomorrow.
Thanks for your input.
Gary

Seems like the OS 46 AX (ABL) isn't widely known for stunt.  This is an R/C ball bearing engine that Tower sells for $140.  Weight is quoted at 13.2 oz without muffler (but with R/C carb).  I converted mine with a stunt venturi and I'm impressed with its power and steady performance.

Floyd

The only way I know to test the power is bye using a fish scale to see how much she will pull. I don't remember how much my OS 40 FSR was pulling, so I'll have to hook her up and check one against the other.

    That will tell you the static thrust, but that doesn't mean very much to in-flight performance and certainly won't tell you much about the power.

    Brett