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RE: New SV Gassers - 1/14/2008 9:32:52 AM   
bako


 

Posts: 105
Joined: 5/8/2004
From: tbilisi, GEORGIA
Status: offline 		I got dubro plastic spinner http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXE149&P=7

works great, though I had to enlarge holes a lot to fin 17X8 prop inside

(in reply to jstanton)
       Post #: 201

RE: New SV Gassers - 1/14/2008 10:07:17 AM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		what should my rpm be tied down ? I spin 8000 with a 16x8, isnt that about perfect ? I dont think it's over reving, it sounds correct up there flying around.

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I dont crash, I just land hard

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       Post #: 202

RE: New SV Gassers - 1/14/2008 10:27:48 AM   
bako


 

Posts: 105
Joined: 5/8/2004
From: tbilisi, GEORGIA
Status: offline 		I think spinner increases rpm. what Iknow for sure, with correct spinner size u have 15% more thrust in high speed flight

(in reply to freeonthree)
       Post #: 203

RE: New SV Gassers - 1/14/2008 10:45:42 AM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		Well, I got the 6 volt 2000ma NiMH battery installed for the ignition now. Maybe that will last longer than 20 minutes. The 4.8 700ma sure didn't. If I calculated it correctly, 1.75kw is almost 3 amps draw at 6 volts, so no wonder that 700ma battery fell on it's nose after 20 minutes... If this doesn't make me happy, I'll stack another one on top of it and have 40000ma ! If that doesn't do the trick, nothing will.

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I dont crash, I just land hard

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       Post #: 204

RE: New SV Gassers - 1/14/2008 10:55:17 AM   
bako


 

Posts: 105
Joined: 5/8/2004
From: tbilisi, GEORGIA
Status: offline 		opps. I got 700 mah nicad for my ignition. so u wanna say it would last maximum 30 minuts?

(in reply to freeonthree)
       Post #: 205

RE: New SV Gassers - 1/14/2008 11:06:15 AM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		Im not looking for more rpm or power, or even speed, I just dont want to lug or over rev the engine. I figure that 8000 rpm, wide open, tied down, will be maybe 8500 in the air unloaded and wide open. Thats pretty close to the max rpm of 9000. Im new to this gas stuff, but im learning. I just hope im readin the right stuff. I read somewhere, that the LSN effects the high speed, but not the other way around, but I turned my HSN last night, and my idle speed changed, so I don't buy that theory at all, not with this carb anyway. Also, I read that these engines idle at 2 to 5 degree;s, and full advance to 28 to 32 degrees BTDC, and the box says auto advance right on it, but I pulled the plug, and the magnet passes the hall sensor no where near 2 to 5 degrees BTDC, it's an inch away from the sensor at TDC ! I would guess it as passing the sensor at around 28 to 32 degree's BTDC. I have to hook up my inductive timing light to this thing and see what really goes on. It appears to me that the timing is just set to full advance, but the timing light will tell...


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I dont crash, I just land hard

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       Post #: 206

RE: New SV Gassers - 1/14/2008 11:14:56 AM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		Thats about all I would get, and then my battery would be down to 4.7 and the engine starts missing terribly, and get worse and worse. The first thing to go is the high rpm. I dunno, see what your does, but if it starts to run funny, check the battery before turning any needles. I've pulled my hair out over this problem, and almost took my carb apart to check the screen when I discovered that my batt was at 20%.
The next time it starts to run funny, im gunna leave the needles alone and look elsewhere.


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I dont crash, I just land hard

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       Post #: 207

RE: New SV Gassers - 1/14/2008 11:27:26 AM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		With the 6 volt, 2000ma NiMH battery, my tester is a V300, and the last red light (10%) is still 5.4 volts, so i'll be able to run er all the way down to 10%, and still have more power than the 4.8 at 100% which is only 5.17 volts. I think you better get one of these 2000ma NiMH 6 volt batts myself, and don't even bother messin with the 4.8 stuff. Just my opinion... I've already been there and done that, and I didn't have much luck. I think the ign pulls around 3 amps.

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I dont crash, I just land hard

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       Post #: 208

RE: New SV Gassers - 1/14/2008 12:06:22 PM   
jstanton



Posts: 1878
Joined: 8/30/2002
From: Millington, TN, USA
Status: offline 		I have been using a new 700MAH nicad battery for my testing on a test stand and I have been getting 45 minutes of running time with it. The RPM has been has been changed from 4000RPM to idle many times when breaking in. Very few runs at Top End. I only use the 700MAH battery for testing. I will be using a 2000MAH 4.8 when I fly. I have 3 gas engines and I use 2000mah 4.8v batteries on all of them. I will check my voltage on the 2000mah battery after a 15 minute test run I do on the ground. Thanks for giving use the info on the battery.

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Jim Stanton
Millington, TN 38053

(in reply to freeonthree)
       Post #: 209

RE: New SV Gassers - 1/14/2008 12:16:31 PM   
Ed Cregger



Posts: 7644
Joined: 1/31/2002
From: Ringgold, GA, USA
Status: offline 		You can't really advance the spark electronically, if you think about it, without moving the sensor, or having another magnet in place.

But, you can run the system at full advance and then have the electronics delay the spark back to full retarded position.

The sensor would have to be psychic in order to do it any other way. <G>


Ed Cregger


_____________________________

Artisan

"Flying models since the Fifties - I'll get the hang of this yet!!!"

(in reply to freeonthree)
       Post #: 210

RE: New SV Gassers - 1/14/2008 6:03:05 PM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		Thats kinda what I was thinkin, it could be delayed at low rpm to make it work, I went to sleep last night thinking about that...

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I dont crash, I just land hard

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       Post #: 211

RE: New SV Gassers - 1/14/2008 6:15:51 PM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		I may be off on my times, I havn't been using a watch or anything. All I can say is that when the planes battery is at 90%, The ignition battery should not be at 20% and not able to run the engine properly. I guess it ran ok for like 3/4 of a tank, and then started going downhill. Keep in mind, I do most of my flying at half throttle and below, so my mileage is probably better than some. So far, I have been unable to get thru a whole tank of fuel before it acts up, and I want to be able to run 3 or 4 tanks at least before charging. The plane and the ign both have 6 volt 2000ma NiMH batteries now, so maybe my luck will change.

_____________________________

I dont crash, I just land hard

(in reply to jstanton)
       Post #: 212

RE: New SV Gassers - 1/15/2008 12:15:34 PM   
freeonthree



Posts: 2562
Joined: 8/1/2004
From: Red Bluff, CA, USA
Status: offline 		I went out last night with the 2000ma 6 volt NiMH and flew maybe 5 times, for 10 minutes each, and the ign battery was at 90% on my V300, much better... Now im sittin here lookin at the 18x6 I just put on it. I had a 16x8, but I don't think it had enough pull for my SV26 on this 15 pound biplane. It even looked a bit small on there. The 18x6 looks like it fits the plane better scale wise. I'll post my flying results tonight. Dennis

_____________________________

I dont crash, I just land hard

(in reply to freeonthree)
       Post #: 213

RE: New SV Gassers - 1/15/2008 12:23:41 PM   
jstanton