Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Burnt up GRRT today

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Old 04-12-2003, 11:39 PM
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FlooredCOBRA
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Default Burnt up GRRT today

I just got back from the field and had a bad day. I only took my dust out to fly today and was hoping for a fun day. It all ended when the engine burnt up.

I fueled up as normal and started to crank it up. It would not crank. I checked the plug and seen it was gone so i swapped it out for a new one. I cranked up again and found it was way to lean and would not run. I kept on richening until I got it running good. But I did not make a few turns on the rich side which was stupid cause I always do. I was in a hurry to fly since wife came with me and was ready to go home the second my foot touched the ground at field.

Anyways I cranked revved it up and launched out of my hand. It was running good for about 1 1/2 minutes or so then i noticed the power sagging off. I should of right the cut engine and landed. But I was being stubborn and kept on going.

I made a few more passes and then the engine finally got even slower and back down to what sounded like 1/4 throttle. I cut engine off and came in to land. This is where i got sick.

I got the plane back to the table and flipped the prop over....no compression. Not good! I pulled out the plug and it was definitely ran hot. The engine did not feel hot but the plug showed it ran hot.

I pulled the head off the engine and seen the head was covered in a nasty black colored smut. The head felt as if it was sand blasted with a black substance. The head was very coarse instead of smooth like before. The top of piston was the exact same way. And the engine had a nasty smell to it. I checked the sleeve and it looked okay I guess except that nasty dark black color at top of stroke. Not good once again.

To top it off I pulled my pipe off to leek through rear of exhaust. There is where I found the nasty piston. I am guessing that somehow the element from the plug burnt out and fell in between piston and sleeve. My piston has a huge gash on the side of it from top to bottom. Guess this is where I lost my compression.

Other than that my Dust flew great!

Well guess thats the last time I try to rush things. And what makes it worse about it I knew better!!!
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Old 04-12-2003, 11:42 PM
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Default Burnt up GRRT today

I'll post some pics as soon as i get it apart.
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Old 04-13-2003, 12:08 AM
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Default GRRT 40?

I have one that needs bearings that I am trying to sell or trade- Would you be interested?

james
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Old 04-13-2003, 12:18 AM
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Default Burnt up GRRT today

Razor, thanks but I already posted my order for a new sleeve rod and piston.

here are the pics
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Old 04-13-2003, 12:20 AM
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Default Burnt up GRRT today

you can barely see the little dent on the sleeve. here is the piston
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Old 04-13-2003, 12:20 AM
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Default Burnt up GRRT today

another
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Old 04-13-2003, 12:21 AM
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Default Burnt up GRRT today

last one.

you can barely see the ding on top of piston. i dont have the best of digital cams but it works
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Old 04-13-2003, 11:06 AM
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Default Burnt up GRRT today

i had a kinda good day too...
got Project magnum running at last, had the 9mm carb, and a 8x8 prop. took off, nice but slow.
Tried a 7.?x8 i made from a tipped 8x8 got the rpm from 14.8 to 15.6 but it was slower.
Gotta try the venturi and get a better prop, having a Leo 37 Funfighter over take you isnt fun
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Old 04-13-2003, 02:21 PM
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Default Burnt up GRRT today

I know how you feel. I had a TT40 eat a plug element in an APRA race, and it looked like that. Switched to McCoy 9s. So far, so good.

Paul
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Old 04-13-2003, 02:59 PM
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Default Burnt up GRRT today

Since I got the engine I have been using McCoy 9s and they been working good.
Just lately I been swapping out plugs to find something different and then noticed burnt out plugs. The McCoy's never fully burnt out like others did.
I tried Hanger 9 medium heat plugs and K&B plugs also to find something different. This is when my problems started.

I think after my piston sleeve and con rod comes in I'll stick with McCoys again. Never had any problems with them before hand.
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