jeffk464

I'm getting ready to finish a top flite 190 and have a tower hobbies .75 engine for it. Anyways, I'm having a hard time deciding what the best way to install this engine would be. Should I go 90 degrees and run with the stock pipe for power output or run a bisson pitts muffler? Or, should I run it inverted with the top flite in-cowl muffler. I'm concerned about power and reliability so I'm really tempted to run with the stock muffler. Can anyone give me an idea on the reliability and power loss effects of the top flite in cowl muffler.

w8ye

My Feedback: (16)

The best things in life are the simple pleasure.

Mount it on it's side. Don't mount the engine inverted.

Enjoy,

Jim

Flyboy Dave

My Feedback: (21)

....what Jim said.

jeffk464

I was kind of thinking that would be the best idea. I also might need every last bit of power this engine could put out, so I think I will go with the stock pipe.

That f20 looks very fast, what kind of speeds are you getting out of it, curious to see what the Tower .75 can do in the right plane.

Flyboy Dave

My Feedback: (21)

Straight and level, about 115-120....tops. The F-20's are kinda fat.

da50ex

Kinda fat? It looks like it's going 200mph just sitting there. Also, that looks like a real nice flying feild, where's it at?
John

Flyboy Dave

My Feedback: (21)

It's El Mirage Dry Lake in So. Cal....about a mile wide and 6-7 miles long. That's
my other F-20, a 45 Rossi powered 40 size Cermark plane. I was racing against
Razor with his Jett 50 powered Patriot....it was a tie !

The surface is flat as a pancake, you can take off or land in any direction.

FBD.

Rcpilot

My Feedback: (78)

Sideways is the best if you want to keep it simple and reliable.

I've used the Bisson pitts muffler on a couple of them when mounted sideways. I encountered the typical problem that most people have with pitts mufflers. Not enough pressure going into the tank. They lean out when you point the nose up. You can plug one side of the pitts and it'll run fine. I shaved a tank stopper down with a razor knife and stuffed it up inside the exhaust pipe. Put a little screw in the side of it to keep it from falling out.

They make great power on the stock muffler.

They make even more power with a pitts muffler and a Cline regulator. Muffler pressure not required. Free flowing exhaust and good fuel delivery.

I have one mounted inverted using the stock muffler. I had a custom exhaust extension machined to move the muffler out 1.5". I needed the exhaust extension to get the muffler outside the cowl with the inverted engine. Doesn't seam to effect power. It's on a Cline regulator.

If you want simple and reliable--just mount it sideways with stock muffler. But there are other ways to mount it and actually get more power or a better fit. Those other methods just aren't as simple.

Iflyglow

My Feedback: (79)

The regulator sounds like a good idea, I also am finishing a GP Shoestring w/ Tower .75 and bisson pitts muffler. The elevation for the tank seems to be pretty good, almost centered on spraybar. I had 2 clines but gave one to a friend for an OS 320 project. I used to use them with saito 100t's and .91's.

Rcpilot

My Feedback: (78)

The Cline is the way to go for any situation where you maybe don't have the tank mounted exactly behind the firewall, or if you want to run an aftermarket muffler. I mostly use it so that I can put my tank on the CG.

I just use whatever muffler fits the airplane the best, and install my tank on the CG with a Cline.

jeffk464

Thanks for all information everyone, very helpful.

Iflyglow

My Feedback: (79)

Rcpilet,
Do you ever have a problem with tanks leaking. When I used cline regulators I used the same tanks that my ys's drink out of (TETRA). The reason I ask is the GP "ARF" tank is allready mounted in the airframe, and the throttle control runs under it (what a design concept).

Rcpilot

My Feedback: (78)

I only use DuBro tanks. Every plane that I put together, the stock tank gets tossed in the can and I replace it with a DuBro.

I wrap them in fiber reinforced strapping tape, both lengthwise and around the body in the front and back.

It keeps them from expanding and looking like a pregnant football. I think that as long as you can keep them from expanding, the seams will hold. I've seen them leak when they weren't taped up.