jstanton

My Feedback: (14)

Here are a few pic's of my SV-26 mounted to my Goldberg Stinson.

jstanton

My Feedback: (14)

Hay! I would like to get a spinner for my SV-26. Does any one know what size spinner will work on the engine? I was thinking it would be an 8x1 or an 8x1.25, but not sure.

bako

I got dubro plastic spinner http://www3.towerhobbies.com/cgi-bin...?&I=LXE149&P=7

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

freeonthree

My Feedback: (1)

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.

bako

I think spinner increases rpm. what Iknow for sure, with correct spinner size u have 15% more thrust in high speed flight

freeonthree

My Feedback: (1)

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.

bako

opps. I got 700 mah nicad for my ignition. so u wanna say it would last maximum 30 minuts? [X(]

freeonthree

My Feedback: (1)

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...[>:]

freeonthree

My Feedback: (1)

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.

freeonthree

My Feedback: (1)

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.

jstanton

My Feedback: (14)

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.

NM2K

My Feedback: (14)

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

freeonthree

My Feedback: (1)

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...

freeonthree

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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.

freeonthree

My Feedback: (1)

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

jstanton

My Feedback: (14)

Dennis,

Good news hearing the new battery took care of your trouble. I have a APC 18x6w on mine and I my have to go to a 16x8 ot 17x8 just because of prop clearance. The 18x6 only has about 1/2 " clearance when the tail comes up on take off. The 18x6 does pull much better that the 16x8. Mt plane well wigh in at 12.5 lbs

freeonthree

My Feedback: (1)

That is promising news for sure J. I feel your pain on that 1/2 inch prop clearance. On the Super Stearman, the 18x6 has maybe 3 inches. I had a 16x8, but I couldn't get the blurbles (missfires) out of the engine except in a steep climb, and no amount of carb tuning, or timing change would help, so I decided to try adding load to the engine with the 18x6. This looks more correct for the size of the plane also. I can't wait to go out and fire it up and see how it sounds now. Im hopeing to see a max rpm of maybe 7500 now, and a smooth sounding engine. last night we were all thinking that perhaps my ign box was goofy, but hopefully it was just due to lack of proper load on the engine. We'll see.... With the SV 26,on there, I believe my Super Stearman weighs somewhere between 14 and 16 lbs. Time to find a fisherman and borrow their scale for a minute.

skiman762

Your correct like ED said the magnets are set to full advance and the box can keep track of the rpm and adjust the timing as needed
It doesn't hurt to put a timing light on it but you will to degree the crank otherwise you won't know what the timing light is telling you though at WOT it should be near the magnet somewhere
you may need to use a short piece of plain plug wire to get the timing light to go
just be careful not to turn the engine without the plug grounded

freeonthree

My Feedback: (1)

Those 2 plugs I bought yesterday had too large of nut for the plug cap, and uses a gasket, so I put those in stock for friends with other engines. I had the NGK number as CPMR6F, but now that I have it right, as BPMR, I called Napa Auto Parts again, and they crossed it over to an Autolite plug that they have 6 of. Yipeeeee ! Im going to replace the plug before I test the 18x6 today.

freeonthree

My Feedback: (1)

Thanks Skiman ! My buddy has a degree wheel from his Brison Manual, so we should be able to get it close without using a light now. Wish me luck !

skiman762

What are the tolerances on the DA or 3W ? so I can see just how sloppy my engine is

freeonthree

My Feedback: (1)

Im not believing that at all. I bet the piston to cylinder fit is just as accurate. Walbro carbs are fine, and bearings are bearings. I suppose it's possible that the cranks may be balanced better in the more expensive engines, but who knows. What else is there besides more detailed outside finishing, good for nothing really, and more expensive advertising which drives up the costs as well. The electronics may be better, but I hear that one of the big brand name cdi boxes had an overheating problem at one time, and mine has never even gotten warm when I checked it, so the real test will be how long it lasts. Weedeater specs ? Our last el cheapo $99.00 weedeater lasted about 10 years, and still ran when I snaged the choke for my plane the other day, so the clearances couldn't have been too sloppy. My SV 26 doesnt sound that much different than my bud's Brison 50 when it's running smooth, just smaller, and I have a feeling today, at least I hope, it will be running top notch. I seriously doubt that the engine itself has any issues. Looks like fine quality to me for a little gas engine.

freeonthree

My Feedback: (1)

I made a little degree wheel tonight and checked my timing. It was too far advanced bigtime ! I had to elongate the slots in the sensor to make it go retard far enough to get to 30 degree's before TDC. Now, the screw on the left is right next to the sensor housing. Here's a pic showing my sensor position after setting the timing.

freeonthree

My Feedback: (1)

OK, I had the current drain calculation wrong, im told by the owner of a LHS. He told me that these CDI ign systems only draw about 300ma, so I guess I put the decimal point in the wrong place.
All I know is that it sure killed that new 4.8 volt 700ma pack real quick. I've read recently where they say not to use less than an 800 ma battery, but I just don't see that as being enough either. now for the weird part.... The guy at the hobby shop told me that he has always used 4.8 volt battery packs for the ignition systems on gas engines, and he can fly for about a week without recharging. I think I better go buy me a new pair of boots ! Maybe he only fly's 5 minutes a day or something. Hmmm... lets see... 300ma draw, he's talking about useing a 600ma pack, and I come up with alot less than a weeks running time. Looks more like an hour to me, before the voltage drops below a useable level, if he's lucky. Hmmm...

jstanton

My Feedback: (14)

I am getting about 1 hour of run time with my 700mah battery. So that one hour you talked about sounds about right to me. I will be using a 2000mah battery when I fly. Let use know how your engine runs with the timing retarted a little more like you have it. Also I would like to know if your RPM changed much.