purge98

What material is it best to use to direct a Jet's exhaust? The Jetcat can produce T4 temperatures of 700 c. I intend to produce a replacement for the end nozzle to direct the gas out along two pipes which narrow to produce thrust at their ends for a vertical thrust application.

Any ideas?

Jason

erazz

You need a material that can withstand these temperatures for some time without being deformed.

The only material that I can think of (being reletively cheap and easy to find and as light as possible) is stainless steel sheet.

SJN

What about Titanium sheet ?

(just a guess)

SJ.

DavidR

My Feedback: (1)

Jason,

If I read your question correctly you are wanting to replace the tailcone on the engine with some sort of thrust vectoring system. If I am not mistaken the NGV bolts to the tailcone sandwiching the outer case in between it and the NGV. If you take the tailcone off you are esentially disassembling the engine and could introduce some alignement problems into the engine. If you are wanting to duct the exhaust gas you are going to need something a little more substantial thatn the thin sheets, of stainless or titanium that we use for tailpipes.

Gordon Mc

My Feedback: (11)

As I understand it (not that I'm anything even close to being an expert in this area, but I have discussed it with others who are), the geometry of the tailcone is quite critical in how the engine performs - so if you are pulling this off and replacing it by something else, you may substantially affect the engine's ability to perform.

Gordon

purge98

Thanks Gentlemen for the replies. Now having taken a good look inside the tailcone i can see that it does form part of the rear support structure of the engine. I suppose in order to avoid unbalancing the engine one could always affix the vectoing tubes to the end of the Jetcat nozzle. I did see on the net a picture of a model turbine which had been modified to power a propellor and that had a similar arrangement to what I would like to do but without the prop. If you see what i mean. Has anyone else seen this and where? Was it a Jetcat?

Gordon Mc

My Feedback: (11)

Best source of info on this, here on RCU, would probably be 'Pegasus'. He really knows his stuff, and has spent a long time working on vectored thrust for a Harrier - see the thread at http://www.rcuniverse.com/showthread...347&forumid=26

Regs,
Gordonn

ajcoholic

My Feedback: (10)

In Thomas Kamps book on models for jet engines (not his book on making jet engines, but the book for installing and using them) he shows diagrams for a vertical take off platform, which uses a duct to redirect the exhaust. I think thats what you are talking about?

I can send a scan of the picture, and you should get the book (through Traplet publications) as it contains a lot of great info.

You wont "unbalance" your engine by removeing the tailcone, as it dosent rotate around with the rotor assembly. But, you would have to assemble it back together with some shims around the turbine wheel and NGV as to recenter it properly.

If you want me to scan and email that drawing let me know.

Andrew Coholic

purge98

Andrew, (ajcoholic) thanks for the reply.

I have found two books on amazon written by Mr. Kamps:
Radio Controlled Model Jet Guide
Model Jet Engines (Modeller's World S.)

Please could you let me know which one you are referring to and I will see if they have it in stock.

In the meantime if you could email me a scan of the image that would be most helpful.

Thanks

ajcoholic

My Feedback: (10)

Radio Controled Model Jet Guide is the one! Brown cover with a pictuire of a jet on it.

Here is a small scan, if you want more info email me:

[email protected]

purge98

Thanks for the scan.

Just ordered book from Traplet uk.

Thanks again

Jason