BJ did you read his thread at all or just click on the link [sm=confused.gif] he has 25hrs on his JJ3000 might be worth asking what size pipe he is using [sm=75_75.gif]

Sorry - I didn't realise there was a thread there somewhere.

All I saw (and clicked on) was the link - which was to a YouTube vid.

Or am I missing something here...[sm=confused.gif]

BJ

That's only link to youtube video,ther is no any thread.

Hi,

The pipe is standard p160 pipe included with Skymaster Viper. I will meassure for you.

Regards

Morne

Sorry, just the wording, meant his post not thread, anyway looks like your problem will soon be solved thanks to morne.

Great...

Thanks Morne and Xair.

I've found it surprisingly difficult to find much info and/or vids about making your own pipes - single or double walled.

I've entered various permutations of single walled, double walled, RC Turbine etc etc and about all I get coming up in RCU and RCG threads is people mentioning them, but not actually posting any build info. I've Googled the same key words, and tried in YouTube, but nada - not a lot comes up.

Maybe I'm holding my tongue wrong? LoL

BJ

For you guys that send your engine for warranty repair, what is your normal turnaround time? 1-2-3-4 or more weeks???

The tube reduction in dia is usually nominal 5-7%, the spacing betweem is more critical. If you have no test bed for thrust try reading RCJI articles about 6 yrs ago or join GTBA for $20.

Paul

Um..."tube reduction 5-7%" - from what to start with? Does that mean that the tube is tapered? If so, bigger diam at the Turbine exhaust and smaller diam end at the rear of the 'craft?

Is there any particular formula for what the dimensions of the bellmouth should be?

And when you say 'spacing in between', do you mean the air-gap between the Turbine's exhaust and the start (bellmouth) of the exhaust tube?

BJ

...still not having a lot of luck finding info on how to build a double-walled Turbine exhaust tube...or what dimensions to run it at...

BJ

Still not seen a thread started by you in RCJets on asking how to build a jet thrust tube ???

Done

http://www.rcuniverse.com/forum/m_9873119/tm.htm

BJ

Hi Guys.

Has anyone of you used the Jet Joe balancer and has successful results with it? I`ve got the JJ 1800 and stripped it down completely,to find out why it had an internal fuel leak. I decided to improve the engine a little and build a new combustion chamber for it. I just completed the press tooling,to make the end caps on the combustion chamber and will press them out,from a stainless steel sheet,tig weld the whole assembly together and see how it works. The shaft assembly will also be replaced with a new one,which is ground between centers - thats why I asked the question about the balancer? I also changed the preload system in the shaft tunnel,as I don`t like the o-ring system.

Any suggestions concerning the balancer will be much appreciated.

Regards

Craig

I don't have a JJ balancer, nor have I used one myself.

But going what I heard others say, they tend to be a bit on the flimsy side.

If you're tig welding your own comubustion chamber and grinding shafts etc., you're probably in a fairly good position to make a better balancer yourself...

BJ

Hi BJ64

Its not that a big mission to make the mechanical part of the balancer,BUT its the electronics which I don`t have any experience with. I have read that guys have had successful results,using the "finger tip" method and the method where the shaft was supported by its bearings in a tube and rotated back and forth,to find the heavy side.

The new shaft which I made,has a rockwell hardness of 42 and it won`t flex at all. The material in the shaft,has a high carbon content,which is ideal when the shaft is annealed. It gets ground to the required specs,because its too hard to cut on a lathe.

I don`t know if there are other owners of the JJ 1800,who have made improvements to the engine?

Regards

Craig

Oh...sorry....

I thought the JJ balancer was just a static balancer - I didn't know it had any electronics on it...

BJ

Hi BJ64

Yes,there must be some kind of electronic device,which measures the vibration as the shaft is spinning. I`ll try the two methods which I mentioned earlier and see how the results compare to each other.

Regards

Craig

Smithy (Knobby1) might be able to enlighten you there KJ - he services JJ's down here, and I'm sure he's got some sort of balancer.

Haven't seen him in this thread for a while, but you might want to PM him and see what he suggests - he knows his stuff and is great to chat with...

BJ

Hi guys. Thinking of getting a Jetjoe 1400 for my first turbine but also thinking of getting a kingtech k-80. The k-80 is a bit over power and I also like how the Jetjoe comes ready to run with everything. I do like the look of this turbine and any advice would be welcomed. Cheers. George

The Kingtech would be a better first turbine for a novice alot more user friendly. The JetJoe's can and do run reasonably well just make sure Brett sets it up and tests it for you.

Get the Kingtech for sure. [sm=thumbs_up.gif]

All depends on budget I 'spose.

BJ

Hi Guys

I`m busy making a new combustion chamber for my JJ 1800 and the press tools have worked very well. I chose to press the end caps out,rather than spinning them on a lathe. I used 0,5 mm 304 grade stainless steel sheeting and it will be TIG welded together,during the assembling process. In the photograph,you`ll see the drilling jig,which made it a lot easier to drill the holes.

Regards

Craig

Noice

Say....I have exactly the same work-stand as you... freaky.

BJ

Hi Guys

I just completed the end caps for the combustion chamber and the holes haved been punched to accept the inconel vapourizer sticks. Now the inner and outer wrappers have to be made.

Regards

Craig