RE: KATANA XL - new release  
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RE: KATANA XL - new release - 10/31/2007 5:26:32 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		That is too low most people are getting numbers in the high 8000 to low 9000 rpm on 15% with thrust 17-18 lbs with the 18x6w apc prop
and with a 18x8 the numbers are in the mid 8000 range
I know some people are closing one of the pitts tubes or reduceing both to 1/4 inch each
look through these maybe you can get some ideas

http://www.rcuniverse.com/forum/m_265238/tm.htm

< Message edited by skiman762 -- 10/31/2007 6:45:42 PM >

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RE: KATANA XL - new release - 10/31/2007 6:55:10 PM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		Believe me, I've tried and read everything. Many people get great numbers from the 1.60 and many others are getting even lower numbers than I am. I've been down the road of closing off an exhaust tube, but that is just to increase the muffler back pressure if you are having fuel delivery problems. I tried that before I had pumps installed and it worked, but reduced the rpm of each engine by about 600 rpm. I went to the pumps and gained that back, but still can't get the numbers that others are. Most of them are at lower elevations than I am, but I don't think that I'm that high.

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       Post #: 302

RE: KATANA XL - new release - 10/31/2007 7:02:20 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		very strange ,
It seems like it should be well run in by now
does your engine shut off if you close the carb down ? ie no air leaks
you might try 15% maybe with the larger displacment it will make a differance

< Message edited by skiman762 -- 10/31/2007 7:11:16 PM >

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       Post #: 303

RE: KATANA XL - new release - 10/31/2007 7:34:10 PM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		Thanks for the tip, I was wondering how to tell if there are any air leaks. Yes, it does shut down fine. Transition is great, low idles (1850 rpm), fast spool up. The one thing that I do find a little strange is that when I lean the needle to get max rpm , then try to richen it up to drop 200-300rpm, it drops about 400-500rpm in one click. The high speed needle is very sensitive with the pumps installed, so I usually set the rpm a little low to be safe. On the last flight I had I decide to forget about richening it up (shouldn't lean out in the air with the pumps anyways) and that made a huge difference. I could finally pull out of a hover.

BTW, those tach readings are max rpm, before richening.

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       Post #: 304

RE: KATANA XL - new release - 10/31/2007 7:37:37 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		Is your pump between the high speed needle and the carb?

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       Post #: 305

RE: KATANA XL - new release - 10/31/2007 7:50:02 PM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		No, it's before the high speed needle. From what I have read that seems to be the most recommended way. Do you think it would be better between?

There is a guy in my club that is getting much better numbers with a 1.60, but he is running 30% heli fuel in his. Maybe that is the only option for my altitude? I'm at the point where I'm willing to try it, for my 3D plane at least (Giles).

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       Post #: 306

RE: KATANA XL - new release - 10/31/2007 8:05:16 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		you should still get fair rpm numbers even at 2200ft maybe alittle loss of thrust for the slightly thinner air maybe I think that happens more when you get higher then your at
If you have the bypass and check valve install corectly you may have the pressure up to high
remember the purpuse of the pump is reliable fuel flow not high pressure
so with your current rpm loss with one click on the HS I would say turn the pressure down till the high speed needle is not so sensitive with the big swing for one click you might be missing the sweet spot

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       Post #: 307

RE: KATANA XL - new release - 10/31/2007 8:14:48 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		Just for the heck of it your fuel is fresh ? I chased a problem with fuel I thought was good ''6 months old ''and it turn out to be bad . I started storeing my fuel in a cardboard box in a cool or at least coolest place I have in the garage


And if all else fail get a 2oz thunder tiger heli header tank and mount it as close to the engine as you can with the outlet just above the center of the carb spray bar and then mount the main tank behind that with the tank plug even with header tank outlet.
I know lots of people say header tanks don't do anything but I can say first hand they do
it doesn't hurt to have a full 2 oz tank right at the carb

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       Post #: 308

RE: KATANA XL - new release - 10/31/2007 8:32:36 PM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		I thought it was fresh, but after what you said I'm not so sure. We can't buy fuel here, so I make a road trip and get a bunch once a year. They sell alot, so it should be fresh when I get it. I bought my current batch in the spring (about six months ago) and have been storing it in it's cardboard box in my garage. The garage has no windows and never gets above 15c (usually 10c or colder), so it stays pretty cool.

I never went with the bypass and check valve. I sent several PM's to people running the 1.60's with pumps on the Great Planes Soucey Extra thread and the Giles thread and everyone recommended against it. They all claimed that it was unnecessary with the 1.60. Maybe I should give that a try? I had to turn the pumps down a little from the factory setting, but after that the engines have been running great as far as idle, spool up and transition were concerned, so I never considering going that route.

I have never thought of using a header tank; do you think that would help with the rpm? I've got lots of fuel flow and haven't had any deadsticks since I installed the pump, so I'm not sure what the tank would do to make things better?

I'm determined to get to the bottom of it this winter though. Flying season is pretty much over here, so I'm going to pull the engines out of the planes and run the heck out of them on the bench. That should make it alot easier to try different fuel set-ups, fuel, props and break them in some more.

Thanks for all of the help. If and when I find anything out I'll be sure to post it.

-Greg

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RE: KATANA XL - new release - 10/31/2007 11:33:18 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		well sounds like maybe too much pressure to me and with your 300-400 rpm change per click you could be going right past the perfect setting to a way too lean condition and then back to a too rich one
most of my engines need 3-4 clicks for that much change
Good luck with it

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RE: KATANA XL - new release - 11/1/2007 3:17:48 AM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		Yeah, I think I'm going to try the bypass setup next. I may even go with the stock muffler and no pump on the test stand just to see what happens. It should be easy to get it to run perfect with the simple stock setup, then try to get it running just as good with the pitts muffler and pump after that.

Thanks for the help!
Greg

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RE: KATANA XL - new release - 11/1/2007 5:40:20 AM   
RobertC



Posts: 280
Joined: 3/6/2002
From: Redmond, WA, USA
Status: offline 		I'm not an expert Greg, but my bet is that your muffler is causing the problem. Not plugging one or the other stack, but volume. Bisson seems to make mufflers that work for multiple engines-- and they don't really try to optimize the volume for each individual engine. You might be suprised to find that the OS 1.60FX has the same bolt-spacing (for the muffler) as the ST4500, and this muffler has a lot more volume. An easy way to find out is go back to the stock muffler, it certainly should give you the best performance!

Again, I am no expert, but I have run a few 1.60FX's and have noticed this difference with different mufflers.

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       Post #: 312

RE: KATANA XL - new release - 11/1/2007 1:33:50 PM   
skiman762



Posts: 1166
Joined: 12/1/2005
From: Nashville, NC, USA
Status: offline 		That would be a good idea if you get your rpm back then at least you know the engines good and go from there
Go over and read through the morris hibby big boy thread in the RTF section many of the guys there run a header and moose can pipe that would fit right in the tunnel and I have seen them run
one was a 11 lb Spoiler with a 160 the blasted out of a hover straight up like a rocket with a 18x6 xoar prop
I read up on the pumps some more and they can be as much trouble as the problem your trying to fix
unless your wanting to put your tank at the CG I can't see any reason for one like I said that Spoiler I saw fly was doing every high G manuver you could think of and that think never skipped a beat
it did have a header tank as well I passed the header tank on the Big Boy thread and the ones the tried it had good thinks to say
the thing with the header tank is the engine always sees the tank as full so there is very little mixture change form start up to landing
Can't wait to see your follow up posts
I know you will please with the power once you gwet that 18x6w turning in the 8000-9000 range that alot of power waiting to get loose

http://www.rcuniverse.com/forum/searchpro.asp?phrase=moose+can&m=2557012&message=both&topicreply=both&forumid=ALL&timeframe=%3E&timefilter=0&top=500&minrank=0&sortmethod=d&criteria=AND&language=single&author=


http://www.rcuniverse.com/forum/searchpro.asp?phrase=header+tank&m=2557012&message=both&topicreply=both&forumid=ALL&timeframe=%3E&timefilter=0&top=500&minrank=0&sortmethod=d&criteria=AND&language=single&author=

< Message edited by skiman762 -- 11/1/2007 2:02:43 PM >

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RE: KATANA XL - new release - 11/1/2007 3:52:49 PM   
G.P.



Posts: 195
Joined: 9/3/2005
From: Grande Prairie, AB, CANADA
Status: offline 		Thanks guys. I think that you may be on to something Robert. I did a lot of reading and one thing that really stood out was the people that were having problems were running the Bison Pitts muffler. I knew of the backpressure problems with the muffler, but I just noticed that alot of the people with low rpm numbers are also running it. I'm going to try the stock muffler and see what happens first. If the numbers come up then I'll try to find a can or another pitts that works better than the Bison. The Slimline sounds like it works great. I was thinking that maybe even putting the stock spacer under the Bison might make a difference.

I have no problem getting the engine to run extremely rich, so I know that I'm getting enough fuel flow. I may have too much pressure if anything, but flow is not a problem. To solve the high pressure I can either turn down the pump, or install a bypass. I may just try turning down the pump and see if I still have enough flow at high rpm's. I'm a little leary of doing a bypass on the 1.60 because of the remote needle. The bypass is supposed to be as close to the carb as possible, which means that one needle will be before the bypass and one needle after. This sounds like it could cause more problems, but I'll try it if nothing else works. I would like to get the pumped setup working though; my Giles has the tank on the CG and I would like to do the same with the Katana.

Thanks for those links Skiman. I haven't been on that thread yet, so I'll see what I can find. I'm wondering about how the header works though. The header goes close to the carb from what I understand, but then how does the high speed needle do it's job? The high speed needle would be before the header tank, so wouldn't it kind of become useless? I'm just thinking that the engine could draw as much fuel as it wanted until the header tank went dry, so nothing would really be regulating the high end. I know this must not be the case since it works for others, I just can't see how.

Thanks for the tips guys. I'm going to pull the engines and try to get tthis figured out once and for all next week. -Greg

< Message edited by G.P. -- 11/1/2007 3:54:55 PM >

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