SCREAMIN' DEMON/ YS .45 FS???
07-31-2009, 12:55 PM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: combatpigg
How does the YS .45 compare with the SJ .46? On one of these 32 inch deltas.
How does the YS .45 compare with the SJ .46? On one of these 32 inch deltas.
yeah I'm also curious, about the comparison, if there is one to be had.
BTW this is all very good conversation in this post.
07-31-2009, 09:50 PM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: still4given
I've never used the SJ46 but my SJ50 is a tad faster that the YS 45.
I've never used the SJ46 but my SJ50 is a tad faster that the YS 45.
The YS will be on top with 30% nitro, but is that fair.
07-31-2009, 11:10 PM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: bob27s
You can not use a bubble tank with a YS. The YS pressurizes the tank, AND it returns fuel to the tank. You can not return fuel to the bubble-jett or tetra, since the pressurized side is on outside of the fuel bag.
One thing on YS tanks - wrap it with fiber-reinforced tape. Keeps it from expanding too much, provides more consistant pressure, and on some tanks will prevent it from splitting over time.
Bob
You can not use a bubble tank with a YS. The YS pressurizes the tank, AND it returns fuel to the tank. You can not return fuel to the bubble-jett or tetra, since the pressurized side is on outside of the fuel bag.
One thing on YS tanks - wrap it with fiber-reinforced tape. Keeps it from expanding too much, provides more consistant pressure, and on some tanks will prevent it from splitting over time.
Bob
MJD
09-05-2009, 04:45 PM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: freakingfast
With an APC 9X9 a good engine (good bearings & piston not too loose) on 15% fuel with a properly tuned pipe should see about 16,300 on the ground. The 9X8 should be about 16,900 when tuned for it. These are peak readings, back off for flight.
The 9X9 is my favorite on a delta, but some guys like the 9X8.
With an APC 9X9 a good engine (good bearings & piston not too loose) on 15% fuel with a properly tuned pipe should see about 16,300 on the ground. The 9X8 should be about 16,900 when tuned for it. These are peak readings, back off for flight.
The 9X9 is my favorite on a delta, but some guys like the 9X8.
Tuned the pipe today to 16 500 with a 9x8 Apc, 16 2000 with a 10x6 , on 15% nitro she comes on the pipe nicely!
what do you think?It worked out to be 3.5" from the glowplug to the end of the header.
Now I just have to find a nice speed plane for it.
09-05-2009, 08:07 PM
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RE: SCREAMIN' DEMON/ YS .45 FS???
The 9X8 and the 10X6 rpms #'s seem a tad low, then again I only use a 9X9.
The header length is close to what I use but I cut the pipe side too to get the length short enough. I have a distance of 11 5/8" from plug to the pipe's apex, but that may not be the same pipe you have so what you end up with could be different.
The header length is close to what I use but I cut the pipe side too to get the length short enough. I have a distance of 11 5/8" from plug to the pipe's apex, but that may not be the same pipe you have so what you end up with could be different.
09-07-2009, 12:20 AM
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RE: SCREAMIN' DEMON/ YS .45 FS???
With the stock muffler they seem to be no better than any other quality sport engine.
Sure would be nice to have one engine turn opposite the other on that.
Sure would be nice to have one engine turn opposite the other on that.
09-07-2009, 01:16 AM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: bob27s
One thing on YS tanks - wrap it with fiber-reinforced tape. Keeps it from expanding too much, provides more consistant pressure, and on some tanks will prevent it from splitting over time.
Bob
One thing on YS tanks - wrap it with fiber-reinforced tape. Keeps it from expanding too much, provides more consistant pressure, and on some tanks will prevent it from splitting over time.
Bob
09-07-2009, 07:21 AM
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RE: SCREAMIN' DEMON/ YS .45 FS???
ORIGINAL: freakingfast
The 9X8 and the 10X6 rpms #'s seem a tad low, then again I only use a 9X9.
The header length is close to what I use but I cut the pipe side too to get the length short enough. I have a distance of 11 5/8'' from plug to the pipe's apex, but that may not be the same pipe you have so what you end up with could be different.
The 9X8 and the 10X6 rpms #'s seem a tad low, then again I only use a 9X9.
The header length is close to what I use but I cut the pipe side too to get the length short enough. I have a distance of 11 5/8'' from plug to the pipe's apex, but that may not be the same pipe you have so what you end up with could be different.
09-07-2009, 08:11 AM
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RE: SCREAMIN' DEMON/ YS .45 FS???
The 1240 is the one I normally use. There should be little difference in power between the two, Just that the muffled one will let you keep your hearing a bit longer.
09-07-2009, 09:32 AM
#38
RE: SCREAMIN' DEMON/ YS .45 FS???
Sounds like you're at a point in header trimming where you sneak up on the final cut that makes rpm either not improve or go down. At the point where you optimize it for ground rpm, it could actually act to limit in flight performance. This is where having a tach is not enough, it would be nice to have a radar gun, too. Trouble is, unless I see a radar gun under the Xmas tree, I doubt I'll ever afford it. I think you are to a point where you should bring the hacksaw out to the field and do the final cut [s] while you see the results in the sky. If the weather holds out, that's what I'm doing today with a .32. The tuning tools are head shims, liner shims, different load props and of course the tach. At some point you hit a wall where the flight speed doesn't change much, but the changes to the engine either make it more or less difficult to run. ANY CHANGE you do that makes the needle need to be opened more is good, any change that makes the needle need to close is bad.
