Avanti XLL from Skymaster
12-03-2014, 07:54 AM
#351
Wow...that KT 210 powered Avanti has quite the annoying whistle.
Anton....could you advise what you found the distance to be from the exhaust cone to the bellmouth/exhaust connection that would NOT cause the whistling?
There is not much room to move the KT 210 back and forth.
Thanks
Dean W.
Anton....could you advise what you found the distance to be from the exhaust cone to the bellmouth/exhaust connection that would NOT cause the whistling?
There is not much room to move the KT 210 back and forth.
Thanks
Dean W.
12-04-2014, 07:41 PM
#355
barry told me a couple years ago my k170 should be .5 to 1 inch from turbine to bellmouth. My rhino for jc was 1 inch as well as specified by Eric , that being said the bellmouth with the avanti is much larger than what I have used so these measurements may be better when measured from where the actual pipe starts to the turbine. This would have the end of the turbine just inside the bell mouth. Try contacting the turbine manufacturer of the turbine your going to use they should know for sure.
12-04-2014, 08:06 PM
#356
I don't believe its a turbine issue, its an exhaust tube design question.
Skymaster AND Sebart have played with various engines in this airframe. Would it not be helpful for either of them to come aboard and help out customers with some approximate measurements, whether it be the 170 or to a 300 ?
D.W.
Skymaster AND Sebart have played with various engines in this airframe. Would it not be helpful for either of them to come aboard and help out customers with some approximate measurements, whether it be the 170 or to a 300 ?
D.W.
12-05-2014, 01:51 AM
#358
Join Date: Jun 2006
Location: Gold Coast, Queensland, AUSTRALIA
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Guys,
I don't see why this jet should be any different from all other jets, when it comes to turbine to pipe distance. The gap that you are wanting to establish is for one main purpose; to get enough air pulled into the pipe when the turbine is running whilst ensuring that the static thrust is not choked.
A good starting point is always 20mm (3/4") - end of turbine exhaust to start of thrust pipe (not the bell mouth). If your take off acceleration is too slow but in flight performance seem fine, then increase the gap by 5mm (1/4"). It is rare to have more than 30mm (1 1/4") and less than 20mm (3/4").
The more important issue is the size (diameter) of the thrust tube. I would not be happy to run any turbine bigger than a 180 into a thrust pipe of less than 100mm (4"). Because no matter how far you put the turbine exhaust from the pipe, there may simply not be enough volume for the turbine to perform efficiently. I am sure Tams or Gramania will give the best advice I this regard as the length of the thrust pipe also has a role to play in relation to it's diameter.
Having said all that, there are so many variables at play here that a truly scientific formula will only be possible when all the variables are known.
Just my 2c
Jan
I don't see why this jet should be any different from all other jets, when it comes to turbine to pipe distance. The gap that you are wanting to establish is for one main purpose; to get enough air pulled into the pipe when the turbine is running whilst ensuring that the static thrust is not choked.
A good starting point is always 20mm (3/4") - end of turbine exhaust to start of thrust pipe (not the bell mouth). If your take off acceleration is too slow but in flight performance seem fine, then increase the gap by 5mm (1/4"). It is rare to have more than 30mm (1 1/4") and less than 20mm (3/4").
The more important issue is the size (diameter) of the thrust tube. I would not be happy to run any turbine bigger than a 180 into a thrust pipe of less than 100mm (4"). Because no matter how far you put the turbine exhaust from the pipe, there may simply not be enough volume for the turbine to perform efficiently. I am sure Tams or Gramania will give the best advice I this regard as the length of the thrust pipe also has a role to play in relation to it's diameter.
Having said all that, there are so many variables at play here that a truly scientific formula will only be possible when all the variables are known.
Just my 2c
Jan
12-05-2014, 02:06 AM
#360
Join Date: Jun 2006
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Neville,
Whistle noise is always airframe related. Not necessarily the design, but most times the installation. Invariably, full bypass ducted installations never whistle. I would venture to say, the guy has a non-bypass installation and he has components placed inside the airframe causing the whistle.
I am sure it will not be a problem on all of these planes. To cure the problem, you simply have to look at the airflow inside your jet and decide where it is being 'squeezed'.
Cheers,
Jan
Whistle noise is always airframe related. Not necessarily the design, but most times the installation. Invariably, full bypass ducted installations never whistle. I would venture to say, the guy has a non-bypass installation and he has components placed inside the airframe causing the whistle.
I am sure it will not be a problem on all of these planes. To cure the problem, you simply have to look at the airflow inside your jet and decide where it is being 'squeezed'.
Cheers,
Jan
12-05-2014, 02:13 AM
#361
Yes I agree, The inlets on these are pretty small, hence the reason the wheel wells are opened up to allow more air in and to stop the canopy implosion problem with the bigger turbines. Will address this when I get there with mine, should be ready to fly end of the month.
Lets see.
Lets see.
12-05-2014, 02:48 AM
#362
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I suggest you seal off the canopy, like we did on the big Vipers - fitting the cockpit inside the canopy frame. That way the suction from a non bypass installation will not implode it.
12-05-2014, 03:56 AM
#363
No Jan, I respectfully disagree with your comment on the whistling. That high pitched sound is NOT internal component related. I have seen several cases of a very high pitched whistle related to the turbine / duct combination. The first time was when Bob Violet was showing a group of us his brand new, about to be released fully ducted F86 with a Ram 500. I have also heard this on a PST Panther, Futura and several other models. In EVERY case adjusting the turbine slightly made all the difference. The reason I ask the question is that there is not much room for the larger engines in the airframe and I really don't want to have to drill another set of holes if the manufacturer already has some data on this.
Guys don't get me wrong. My build is progressing well and I am overall happy with the kit. I have several other Sebart models and the response from reps and the manufacturer has been very good. On this particular model, the lack of on line support from Europe as well as Asia has been somewhat disturbing.
Perhaps my concern is unfounded as the videos of Saba are nothing less than spectacular but then again the guy could probably make a 4X8 sheet of plywood fly well.
well, lets get back to building...
Dean W.
Guys don't get me wrong. My build is progressing well and I am overall happy with the kit. I have several other Sebart models and the response from reps and the manufacturer has been very good. On this particular model, the lack of on line support from Europe as well as Asia has been somewhat disturbing.
Perhaps my concern is unfounded as the videos of Saba are nothing less than spectacular but then again the guy could probably make a 4X8 sheet of plywood fly well.
well, lets get back to building...
Dean W.
12-05-2014, 06:53 AM
#364
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Generally, the turbine is too far away from the pipe when it whistles like that. It's nothing to do with internal components, they airflow over them simply couldn't get fast enough to generate a noise like that!
Move the turbine back 10mm to start - this usually fixes it. On the Aurora thread there was a chap with an awful whistle. He moved his 210 back 10mm and it went away.
Move the turbine back 10mm to start - this usually fixes it. On the Aurora thread there was a chap with an awful whistle. He moved his 210 back 10mm and it went away.
12-22-2014, 01:34 PM
#365
Anton, I need verification on the thrust pipe length not including the bellmouth for the P200/Mammoth (50-52lbs)thrust class. I think I have the pipe for the B300 class (75lbs) Thanks
12-22-2014, 06:15 PM
#366
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Hi FenderBean
Please send email to us ([email protected] ).And advise your address and we will check record and get back to you via mail.
Best regards
John
Skymaster
Please send email to us ([email protected] ).And advise your address and we will check record and get back to you via mail.
Best regards
John
Skymaster
07-19-2015, 08:05 PM
#368
09-23-2015, 06:29 AM
#369
09-28-2015, 08:44 AM
#371
Anton,
Attempted to email John but have not heard from him.....on holiday?
I have one of the first batch Avanti XXL and my main gears are now collapsing when filled up with fuel, ready for take off (main gear strut air valve on top of strut, have to remove from base to access oil/air fill valve). I tried to add air (120psi) and assume I let more air out because it is now worse.
How much air should I add and what kind of oil do I use for the struts? Other treads indicate it is transmission fluid (oil) but the oil in my gear strut is gray...not red. I want to try to add oil and air to get the struts back to where they were when they were new.
Thanks!!
Attempted to email John but have not heard from him.....on holiday?
I have one of the first batch Avanti XXL and my main gears are now collapsing when filled up with fuel, ready for take off (main gear strut air valve on top of strut, have to remove from base to access oil/air fill valve). I tried to add air (120psi) and assume I let more air out because it is now worse.
How much air should I add and what kind of oil do I use for the struts? Other treads indicate it is transmission fluid (oil) but the oil in my gear strut is gray...not red. I want to try to add oil and air to get the struts back to where they were when they were new.
Thanks!!
Last edited by TJPro351; 09-28-2015 at 02:00 PM.
04-02-2016, 08:15 PM
#375
both Avanti XL powered by K-210,
https://www.youtube.com/watch?v=TLNcyxN_kYU
https://www.youtube.com/watch?v=n5Gq3GUGW1o
https://www.youtube.com/watch?v=TLNcyxN_kYU
https://www.youtube.com/watch?v=n5Gq3GUGW1o
