Reading through the posts here, it seems that the PA 51 is a engine that is best used with a tuned pipe. I'll admit I'm no fan of the added complexity of pipe tuning and modifications to the airframe to accomodate the pipe, (An additional point of failure / variable). I firmly belive in KISS but will deal with a pipe setup if I must. So is a pipe required on this engine for good, consistant, reliable runs? Is anyone using this engine in a more traditional application with excellent results? In another thread Randy suggested that a PA 51 would work in the SV 11 ARC.

My last plane was a Vector 40 built from a kit many moons ago, had to sell it when life took one of those ugly turns.

Reading through the posts here, it seems that the PA 51 is a engine that is best used with a tuned pipe. I'll admit I'm no fan of the added complexity of pipe tuning and modifications to the airframe to accomodate the pipe, (An additional point of failure / variable). I firmly belive in KISS but will deal with a pipe setup if I must. So is a pipe required on this engine for good, consistant, reliable runs? Is anyone using this engine in a more traditional application with excellent results? In another thread Randy suggested that a PA 51 would work in the SV 11 ARC.

My last plane was a Vector 40 built from a kit many moons ago, had to sell it when life took one of those ugly turns.

Hi Peter,

You can use the PA 51 with a header muffler.  Randy has separate mufflers that connect to the header, and also headers that are made with baffles to use as a muffler.  Either of these will work on the PA 51 with no problems.

Before there was a PA 51, I flew my SV-11 in competition with a ST 51 and it was an awesome set up.  Now I have the PA 51 and it is a better engine.  I plan on using the PA 51 in my next USA-1 with a header muffler.  Many are flying with the header mufflers, so no problem.

The pipe set up, as Randy suggests, is super simple.  Not at all like the horror stories of when the pipes first came out and people were experimenting with set ups.  Now it is plug and play.

Big Bear

Funny thing was, it was pretty much plug-and-play then, too.

HI Brett,

Fortunately, I tend to listen to those who have gotten things worked out! LOL!!  When Aaron, and I, went to the pipe, it was the OS 40VF.  Called Paul and got THE set up!  Billy and Bob also helped, along with Randy.  But Paul's set up worked perfectly!

When we went to the PA engines, called Randy and got THE set up!  So far, that is all that has been needed.  He lives in ourt region, built the engines, etc., so his set ups work perfect for around here.

Best thing is, all I had to do was put fuel in the plane and fly.  Trimming the airframe was the situation then, not the power train.  I do know that there can be situations where the pipe *might* need a movement, etc., but so far it has worked out just fine for these old boys.

I love the *simple things*  such as the BBTU OS 21FP!

"target fixation" is a great description

Bill

Thanks for all the great input. I agree that the pipe is probably the least critical item when it comes to run stability, it should be one of those "set once and forget" items. But it is yet another thing to deal with if things are wonky.

   Think of it like this - if things go wonky, the first thing to try is *not adjusting the pipe*!  Aside from the pipe length, there is *nothing* that is different from a muffler system. And we already know what pipe length you want for a given combination. So the problems and troubleshooting are exactly the same as you have with any other system.

    I am not trying to talk you into anything. A PA51 on a muffler will be a great engine and is something we could have only dreamed of 25 years ago. But I hate to see anyone talk themselves out of anything, either.

    Brett

Hi Bill,

I'm a bit confused. With my Vector 40 (attached in a pervious post) I had an 11 X 4 prop. I clearly remember that if the tail during take off would come up level, the prop had perhaps 1/2 to 3/4 inch clearance from the ground. I would always be mowing the lawn if I tried a nice smooth take off run. Obviously flying from pavement I could roll out let the tail come up continue to rool for a few more feet before lifting the plane up gently in a smooth take off run. This was almost impossible from grass unles the grass was putting green short.

At that time I was wishing for a 10 in 3 blade solution, but good 3 blade props in that size were scarce. As you can see in the photo I like to detail the LG of my models, I would not have been able to keep those pretty wheel pants with standard size 2 inch wheels. I guess that if I want to keep the low slung good looks and landing gear treatment then I'll just have to get used to finding paved areas from which to fly. I just happen to hate the way naked wire or aluminum gear look. It makes the model look somewhat unfinished.

Grass in Florida tends to be thick, heavy wide blade, rough stuff. (Bermuda Grass) It has to be to survive the heat. I guess I'll just have to live with finding areas that have some sort of smooth surface to fly from. Hmmm. I wonder if the Pratt & Whitney facility is deserted on the weekends.

Hi Bill,

I'm a bit confused. With my Vector 40 (attached in a pervious post) I had an 11 X 4 prop. I clearly remember that if the tail during take off would come up level, the prop had perhaps 1/2 to 3/4 inch clearance from the ground. I would always be mowing the lawn if I tried a nice smooth take off run. Obviously flying from pavement I could roll out let the tail come up continue to rool for a few more feet before lifting the plane up gently in a smooth take off run. This was almost impossible from grass unles the grass was putting green short.

At that time I was wishing for a 10 in 3 blade solution, but good 3 blade props in that size were scarce. As you can see in the photo I like to detail the LG of my models, I would not have been able to keep those pretty wheel pants with standard size 2 inch wheels. I guess that if I want to keep the low slung good looks and landing gear treatment then I'll just have to get used to finding paved areas from which to fly. I just happen to hate the way naked wire or aluminum gear look. It makes the model look somewhat unfinished.

Grass in Florida tends to be thick, heavy wide blade, rough stuff. (Bermuda Grass) It has to be to survive the heat. I guess I'll just have to live with finding areas that have some sort of smooth surface to fly from. Hmmm. I wonder if the Pratt & Whitney facility is deserted on the weekends.

Hi Peter,

The SV 11 is a much larger model than the Vector .40  We have a Vector 40 and had the SV-11.  The SV-11 is one of Randy's "large" planes.  670 sq. in. IIRC.  Meant from the start for .60 size engines.  Like I said, I flew the SV-11 off of grass most of the time.   Maybe you would want to put 2 1/2" wheels on your SV-11.

Bill