Thread: .020 size GLH
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Old 12-18-2013, 12:37 PM
  #140  
hllywdb
 
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Location: Vero Beach, FL
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OK, lots to report today. Got pictures of the prop next to the Cox grey and the APC 4.2. The first test was to cut down the prop to 4" and run it on the stock TD. I used my handy prop reducer made by drilling and tapping a piece of angle to take an #8 bolt which fits perfectly in the hole, which by the way is much smaller than the APC. Just needs a thin piece of tubing. The prop size locater (also known as vise grips) easily adjusts to any size. This yielded 20500 on the stock motor. This will give me a tad over 53mph if it doesn't pick up anything in the air.

The dominator project had some hurdles, lots. 1st off the small TD just doesn't like pressure. After an abysmal run with the dominator, I swapped out the stock one and got equally bad results. So off went the backplate and on went the tank. Also swapped out for a stock piston/cylinder set. Since I am still waiting for a tank back, I ran it on an external tank. Once I got a good base run with the cox grey prop, I then hogged out the stock 020 venturi. This did ok with the 4" prop but needs to spin higher with the opened up venturi. So I shaved the prop down to just under 3.5 and was rewarded with 23,800 steady. This translates to 62mph if it doesn't unload at all. If it picks up a simple 1200 rpm in the air I'm at 65mph, and this is with a stock piston/liner. I still have room to hog out the venturi and I can cut the prop down a bit more if needed. So I think 70 is doable, but it will be in small increments.

I'm kind of glad the pressure didn't work out as I have no room for any kind of comercial tank in there. Hav't flown it yet as it's windy today with the front coming through. So maybe in the next few days I will get a flight or two on it.

By the way MJD, these turned out easy to balance, probably because they are so thin that a little here or there doesn't make a bunch of difference.

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