Hi all and Happy Thanksgiving,

Does anyone have an authoritative source of information on pipe specs vs turbine class? I am thinking inlet and outlet diameter vs. thrust, wall thickness vs. diameter and thrust, benefits of taper from inlet to outlet, gap from exhaust cone to bellmouth, impact of pipe length on the other dimensions, etc.

At the moment I am mostly interested in pipe specs appropriate for 300 N-class motors, with an eye on appropriate inner pipe diameter and wall thickness. A few examples of working setups for this size motor would be great.

In the post-Tam world the prior algorithm ("just ask Tam") is not working anymore :-(

I am thinking we have at least tribal knowledge on this, perhaps there are other sources of expertise available?

thanks for any info

Dave

Some info requested can be found in this old 2015 JetCat guide...I just edited attachment to a pdf download and easier viewing. I tried finding a 2017 catalog, but no luck on jetcat.de

Turbines are so different (OK less so with the 300 class) its not an exact science other than experience. There are several companies in Germany making pipes, Grumania would be a good place to start.
Or give your turbine, pipe length, max dia info and people will chip in.

Dave, I would second Dave's point related to Grumania. They're the manufacturer of the pipe in my Rebel. It's very light, I'm overpowering the jet by 40-60n and it has held up real well.

sc

Hi all
This is something I have also been wanting to find out more info on and maybe the chaps that have a Fly Eagle F16 1/4.6 can help. The tail pipe they supply with the kit would it work with a K310G2 and also has anybody fitted a 31 kg to a airframe like this. If so what tail pipe did you use and how did the airframe hold up to it.

Have a great day

Regards

JB

I also want to ask why do we use stainless steel? vs regular Steel? a

My pipe on my Aviation Design Diamond, running a K210 has a very very thin pipe, and it ripped, (I accentually picked it up with my hand in the pipe)

I have been trying to find stainless to make a new pipe as its only 14in long, but this thin of stainless steel seems impossible to find.

That is why I like this post, I'm thinking of going up to .015 Stainless vs the .010 that is on there now, I believe these bigger motors K210-310 need a thicker pipe

" I have been trying to find stainless to make a new pipe as its only 14in long, but this thin of stainless steel seems impossible to find"
https://www.mcmaster.com/#standard-3...heets/=1ada5gr

Stainless oxidises less at high temperature, so less corrosion. There are different grades in the 300 range, the chromium content allows for the temperature tolerance above 500degrees

0.15 is more like it! Short pipe the weight penalty is low

Stainless 316 will implode very easily if used as pipe material.

Oli,
What type of material is needed for 300N pipes?

Gary

Hi

​​​​​​can you elaborate more, please? There are some manufacturers that make aluminium pipes that are more prone to implode that ss. Also possible implosion would differ from straight to bifurcated

br
Nuno

Aluminum for primary pipe? It should be ok for secondary, but at the typical exhaust temps it will galvanize useless. Either that, or you have some really good air mixing going on in there. Even some chinese low quality steel pipes corrode (and cook) horribly, and prematurely.

BTW we now have an excellent supplier of pipes sateside!

sorry RCU blocks facebook links. Try searching J.E.T. Pipes on FB.

DavidR

Sorry
i meant steel+alu

Hello Oli, why 316 is no good?


.

Hi

Right now a friend of mine is making me a Skymaster F4 pipe (bifurcated) with this SS316L steel

It was the SS with better strenght/temparature ratio I could find. Sure looks better than the SM original pipe

Regards

Nuno

309 and 310 are better, but problem is availability at those thicknessses

Isn't it more of a design issue rather then material? Look at a car engine, aluminum pistons and head with temperaturs well over 1000 Celsius.

here's the direct link

https://rcjetpipes.com

.?