Pete737

Hello everybody, just a quick question regarding scale flying. Im thinking about the century L-Ranger for my rap 50 (o.s 50 hyper). Why is it that everytime I see a scale pic exhaust is blowing out the bottom? Ive never worked with (or even seen) a scale exhaust system, but the pic on centurys site shows the scale muffler and it looks like theres a fitting of some kind on the top that you can run tubing from (thats my take on it, please excuse my inexperience if this is not the case) How can you get smoke to blow from the exaust nozzles or exhaust pipes on the scale model.

Sincerely Pete

BarracudaHockey

My Feedback: (11)

The more tubing you run the better chance you have of over heating the motor.

Pete737

Hmmmmmm.....

Pete

Helijack

Most of the "Scale exhaust" are items that will fit into a fuse, not scale per se. You can route it out with pipe, tube, etc, but any exhaust coming out on the top part will get oil and gooo all over the pretty paint job, so many of us flying glow scales dump it out the bottom. Extending the exhaust may cause overheating too, be careful
Jack

BarracudaHockey

My Feedback: (11)

Emile aka Coptor Doctor on the other forums is dead set against it and he's one of the permier scale guys in the country, for both the reasons stated above.

Gorgok

I think the amount of smoke nitros pump out makes any 'scale' attempt pretty much not scale...

Helijack

I certainly agree.

BarracudaHockey

My Feedback: (11)

Yep. I think electric is the way to go. No worrying about fuel proofing, paint how you like, no exhuast routing issues and a turbine like sound.

Pete737

That hurts guys

Pete

Christopher J

This is why I run gas powered ships, you can extend the exhaust without much problem. Also there is no smoke on a gasser.

Pete737

I wanted to go gas, but my local hobby shop recommened I learn with nitro. they had 2 models RTF a R30 and 50, I love the 50 but had I known how well I would take to helis I would have started with gas. Anyway I already ordered the Century L ranger, cant wait for it to get here![sm=regular_smile.gif]

-Pete

Pete737

Has this man done the impossible (or impropable)?

[http://scalehelicopters.org/Huey3.jpg]

Pete

Crazy Ant

Hey Pete,
I saw this one a few weeks ago.(if it's the one I think it is, the address above won't get you there)the green and white Huey is a nice looking bit of gear, is a gasser that is less susceptible to heat build up, and even he didn't think is was worth the effort
regards, Glen
www.scalehelicopters.org/ go to chapter 3

Helijack

Glow has smoke. The more nitro, the more smoke, because they have to increase the oil content to cool the engine for the higher nitro contents. The only glow engines that don't smoke horrifically are the Webra, Rossi, and Laser engines -or- any other engine that will run on FAI fuel (no nitro)

Then the gassers put out a little smoke...think about your weed wacker, not too bad...tolerable.

Electric is great, no mess, just worries about batteries and such.

Of course the very coolest is the turbine, and it is not messy, smells like a real aircraft, has cool noise, and will make you the envy of everyone at your field....LOL

They all fly, they all are fun. You LHS was right for you to learn on a glow machine.
Jack

Crazy Ant

Helijack ,
I'm biulding the raptor longranger project, where can I find out about the engines that don't need Nitro? I don't like smoke, and I don't need super performance
Regards, Glen

Pete737

Oh thats smoke? I thought it was steam[sm=spinnyeyes.gif][sm=wink_smile.gif]. I realise smoke negates your scale attempt, personally I like it, just not the burning eyes when you let the wind get ahead of you. I just wanna route it out the scale ports for my own personal satisfaction. If it has to blow from somewhere, why not the ports? is it a cooling prob? paint?.... surely someone has done it.

regards, Pete

red_sash

OK, if you want to try, I did run a scale exhaust on my H500 for a while, but went electric when I got sick of cleaning up the exhaust residue off my scale beauty.

Use formline brand thin walled stainless continuous convoluted tubing. Use a diameter at least 3 times (or bigger) the exhaust outlet on your muffler. Therefore, for an 8mm outlet on your muffler, use the 22 or 24 or 26mm tube (can't remember exactly). Keep the run short (I'd say no more than 15cm or thereabouts). Use silicone tube as the joiner to the muffler outlet.

The tube is quite light and it because it is convoluted, it bends with a continous diameter, so flow theoretically should quite efficient. However, in practice, the convolutions catch the excess fluid in the exhaust, and it can build up, begin to trickle back towards the muffler outlet and eventually block your exhaust almost completely.

In worst case, ruin your motor, because the motor can't eject the exhaust efficiently, because of blockage. Therefore, at the lowest point of the formline tubing, and probably just past where the muffler enters the formline tubing, mount a pressure nipple pointing down, and run the excess fluid out a small diameter silicon tube.

Worked for me with no overheating problems. Just messy, and the joiner never worked 100%. Just use as larger diameter as possible, shorter run as possible, and dump any excess buildup. Take other precautions - good fan (maybe upgraded CNC fan), model not too heavy, correct gearing, and maybe 30% nitro.

Christopher J

Crazy Ant,

You would need to look for a Webra or Rossi engine in the 50 size range. These motors have a higher compresion and run on low, to no nitro fuel.

Michael211

My Feedback: (1)

I'm doing a 60 sized Century Airwolf. Seems like a simple and short run to direct the exhaust from the back of my Hatori muffler to the lower exhaust outlets on the Airwolf fuse. Planning to fashion a T from some brass, then 2 short runs of silicone exhaust tubing straight to the scale exhausts.

Am I missing something here that's going to cause problems?

Thanks.

- Michael

Christopher J

If you're going to do that make sure you size up on your exhaust tubes. The longer your run from the muffler the more backpressure you will have but if you use tubing larger then the muffler exhaust tip you will aid in reducing the amount of increased backpressure.

Michael211

My Feedback: (1)

Thanks Chris. Question though.... I plan to T the exhaust off right at the back of the muffler into 2 exhaust lines, one to each side of the fuse. With 2 exhaust paths do they really need to be that much larger in diameter?

I realize there may have to be some trial and error on this project, and I will be mounting a digital engine temp sensor with the display visible from 1 of the side windows so that I can easily monitor the temps in there.

Finally, I'll be making 2 cutouts in the bottom of the fuse, one on either side of the center-rib that runs the length of the fuse, and putting wire screen on them. This way hot air from the cooling fan shroud will have (I hope) a better/faster way to get out of the fuselage! [8D]

Of course 1 big advantage of the Airwolf scale fuse is those nice large open jet engine air intakes right behind the cockpit doors. They surely must help air to flow into the model when in forward flight!

- Michael

rcjetfan

Man trust me on this. If you can afford a trubine its the best power source that I have found. I recently got my hands on a Larry Jolly studio Airwolf kit that will be powered by a turbine. I am having scaled exhausts made out of metal and the best part about turbines other than power and sound is there is no smoke like in nitro and gas.

Michael211

My Feedback: (1)

Lemme see.... rich relatives with heart conditions, Zero. Nope, I can't afford turbine power. Sowwy. [&o]

Maybe someday, but for now nitro will have to suffice. Regards and best wishes.

- Michael

Michael211

My Feedback: (1)

On a similar vein, what exhaust system(s) fit best in scale fuse's? I finally bought another set of X-Cell mechanics for my Airwolf project (Century 60 size Airwolf) and when I placed the mechanics inside the fuse I realized that a straight tube muffler (like Hatori pipes) won't even begin to fit.... there's a 1 inch tall wood bulkhead running across the belly from rear retract to rear retract, with a structural pipe on top of that! Ergo, I can't use the log pipe I have. I used to have a pipe with a header that curled upward and then back to which the pipe then fastened with a silicone coupler to, but I sold it last year not realizing I'd ever need it! Since I don't know what that pipe was exactly, I'm now having a hard time trying to find another like it.

I guess what I'm trying to say is that I'm having a difficult time finding an exhaust system to fit inside this 60 sized bird now. It's got to be one that mounts higher up on the heli mechanics with a header pipe.

Can anybody suggest something that'll work that I can lookup online? I don't like that Century "scale" muffler thingy (I have one if anybody wants it!). It doesn't properly clear the X-Cell frames and I've heard it's a total horsepower hog. [&:]

Thanks!

- Michael