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Extreme Flight 104 Extra 300

Capt.Roll

70cc twin V2
And empty of fuel. For planes with the fuel tank in front of the CG always measure CG with the tank empty because you want to measure the plane when it is "most tail heavy". As the tank empties it the CG will move back so you want to know what it will be at it's "worst".

For planes with the tank aft of the CG (not that I've ever seen one) you do the opposite. You measure CG when it is full because the CG will move forward as you burn fuel.

Make sense?

Finally got around to resetting my CG this weekend. With rope around the wing tube and lifted off the ground the plane will hang level without any fuel. With 32 ounces of fuel on board the plane does drop the nose. I would say at this point more than my liking but won't really know until I can get it in the air. Weather forecast for Saturday looks decent for a maiden.

Pics show component placement with room to move Fiji back against the wing tube sleeve as well as being able to move the two batteries forward or aft several inches each way.

104 CG1.jpg


104 CG.jpg
 

camss69

70cc twin V2
Finally got around to resetting my CG this weekend. With rope around the wing tube and lifted off the ground the plane will hang level without any fuel. With 32 ounces of fuel on board the plane does drop the nose. I would say at this point more than my liking but won't really know until I can get it in the air. Weather forecast for Saturday looks decent for a maiden.

Pics show component placement with room to move Fiji back against the wing tube sleeve as well as being able to move the two batteries forward or aft several inches each way.

View attachment 16072

View attachment 16073

It looks good and I'm sure it will fly well. I doubt you will see much if any difference moving the fuel tank and batteries back to the wing tube. My batts are as close to the wing tube as possible. I used a piece of the fuzzy size Velcro stuck to the wing tube to keep it from rubbing on the fuel tank. I'd say you are good to go and if you want to a more aft CG make that change after you fly it. I've never checked the CG with fuel always without.
 

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Capt.Roll

70cc twin V2
I'm so disappointed..........Took my Extra out to the field on Saturday for its maiden and the dang engine would not start. Tried for three hours and could only get a single "pop" about every 50 flips. Wasn't even a good "pop"..........it seemed like it was firing when the piston was towards the bottom of the stroke; or at least with the exhaust ports somewhat open.

Did some basic troubleshooting at the field with no success. I'll work on it some more this evening when I get home from work. If I had to guess now I'd say the ignition module or hall sensor has gone bad.
 

49dimes

Damn I'm hungry
I'm so disappointed..........Took my Extra out to the field on Saturday for its maiden and the dang engine would not start. Tried for three hours and could only get a single "pop" about every 50 flips. Wasn't even a good "pop"..........it seemed like it was firing when the piston was towards the bottom of the stroke; or at least with the exhaust ports somewhat open.

Did some basic troubleshooting at the field with no success. I'll work on it some more this evening when I get home from work. If I had to guess now I'd say the ignition module or hall sensor has gone bad.


Rex,

Bypass your IBEC and plug a battery directly to your ignition and see if it starts ok. If it does you know it is in a connector or IBEC itself. Sorry for your disappointment. But knowing you.....It will be perfect soon.
 

Capt.Roll

70cc twin V2
Dang Dimes..........wish it was that simple.......LOL. At the field Saturday I did try a 2S LiFe plugged directly into the ignition......no change. This is a HV ignition but did not try a 2S Lipo. I do have new CM-6 plugs installed; gap is 0.020".

Also checked for spark, fuel to the carb and pump diaphragm wet, and fuel getting into the cylinder. Engine seems to be pulling fuel well as I can get fuel dripping from the carb with the choke fully closed and flipping the prop.

This evening I'll check the timing of the engine and make sure it is in the 28-30 degree BTDC range. If good there I'll take the ignition off the Extra and put it on my Dalton with a DLE-111 and try it there. The DLE starts very easy. If it works at that point then I'll take a look at the Hall sensor. If all is good with ignition and sensor I'll unbolt the carb/reed block and give those a quick check.
 

Terryscustom

640cc Uber Pimp
Dang Dimes..........wish it was that simple.......

Sounds like one I had once on a 40cc twin. Flip until my arm hurt with only a dozen small poofs....not even a real pop. Timing, spark, carb reeds, BEC all ruled out. Turned out is was sparking but a very weak spark. Installed new ignition I had in my trailer and two flips it was running like a watch. Engines will "run" at any place that the timing sensor is within the range of adjustment, so with your symptoms I would not waste time checking timing unless you want to do it for fun. If you are dripping fuel that pretty much rules out carb / reeds as it would still fire at some point unless it is extremely flooded.

I'll bet that DLE ignition brings it to life instantly. If not I would try the hall sensor.

All you need is air, fuel and spark to at least get a pop. So for major problems like yours that's the only place to start. If it's running but running poorly then its time to dig further into the carb, timing, etc.
 
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