raron455

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okay I have a question for you fellas, I recently picked up an elan that has a p-70 in it I also got a smoke setup for it with the Jet tech partitioned tank and a tamjet smoke pump with twin nozzles, but I am confused as to where to place the nozzles. I have always read that you try to get the nozzles in the center of the turbine outlet however, the p70 has a weird tail cone it has an inner cone as well as the main one and I'm not sure if I am supposed to try to put the nozzles in the center of the little cone in the middle or just try to get them in the flow of the main cone any help on this would be appreciated I have never seen a turbine with an outlet like this

raron455

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anyone know,, I have tried to find a pic of a smoke setup on a p70, or a setup guide, but no luck,, The exhaust on the p70 is an odd duck, don't see any like it,,,

Terry Holston

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I have a Wren 160 on my KIngCat and only use one nozzle.( I know your engine is smaller but I am sure they both get just as hot.) I have it mounted on the top with the tip just inside of the hot flow, so as not to shoot any fluid on the airplane. Works great, I get all the smoke I could want.

DrV

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I'm not sure if this will help. This is a plane I purchased and the owner had a P70 in it with a smoke system.

raron455

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Yes sir, that does help, thats exactly what I was looking for, thank you for the install pix.

raron455

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Wanted to post an update for any interested,, here is where I ended up putting it,,, SMOKE Is nice and thick,, should work out great,,

FalconWings

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Ha ha Ronnie, that is actually a cool spot on the engine exhaust (just downstream of the tailcone, where air tends to separate), still pretty hot, but I would cut out the tube about .5 - .75" , that would spit it on the area where the hottest expanding gas is.

but then again, what you have is probably good enough. :-)

David

raron455

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David,, thanks I did not know that center was the cools spot,,, the little cone on the p70 is just weird,, wonder why its like that, I will move the tip into the main exhaust on the outside of the cone and try that and see if the smoke is any better,, good thing Is I can just grab the smoke tube and bend it back a little bit and then back towards the cone...looks cool with the smoke, I like it..I have actually had a lot more fun flying it it than I thought I would. I will be at the Houston Jet rally Friday morning,, You gonna be able to make it??

FalconWings

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I dont think so man. Its very busy at work, and Im finishing an F-16. I'll try to go to the next Waco day in April.

flyinfool1

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I have been watching this one close. I have a P70 in my R54 and have started putting in smoke.

Thanks for starting this thread.

roger.alli

I'll have a crack. My understanding, is that the exhaust cone functions to control the gas flow as it leaves the turbine disk. It covers the solid part of the disk and creates a nice flow path between it and the outer exhaust nozzle. Thus reducing turbulence in this area and increasing velocity and thrust. Most full size engines uses some kind of exhaust cone, although it seems many model engines don’t feature them.

I know that Gasper has not used them on the VT 80 or the M140.. But he has included them on the new M 200. I guess that not all model engines benefit from them..

Disclaimer:: I am very much an amateur turbine enthusiast.

raron455

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No Problem,, I will be flying the Elan this weekend with smoke, I will move the nozzle to the outer part of the exhaust flow and see how that performs,, I will get some pictures and post of nozzle placement and in flight smoke trail,,

Also For details, I am using a Sullivan skywriter smoke pump (same kind I use in my aerobatic planes) and a 1000mah 2s lipo battery to the smoke pump, I have this same setup on a 1/3 pitts and easily gives 2 flights with smoke before needing a recharge and the batt weighs next to nothing,, Nozzle is a piece of stainless that I crimped the end of, first using a set of pliars to flatten the end Not quite closed, then taking a pair of side cutters and crimping the middle of the pipe, sealing it up making two small sprays at the end of the tube...

FalconWings

My Feedback: (57)

The kind of performance improvement you get from having a tailcone wouldn't affect us much. It helps lower EGT some, and increases turbine performance at the top end.