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"Slingshot" for methanol and gasoline aircraft engines

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"Slingshot" for methanol and gasoline aircraft engines

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Old 06-22-2014, 12:20 PM
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a@l
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Default "Slingshot" for methanol and gasoline aircraft engines

We name this device as "slingshot". There is a sand on bottom and U profile on top. When we adjusting gasoline engines, hot gases and fuel residues destroy the grass. "Slingshot" rotates around the vertical axis, therefore pressure on both wings is the same. On vertical pillars there are soft armaflex pipes.







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Old 06-23-2014, 04:16 AM
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Have you had problems with engines ingesting the sand, or having props pick up the sand and blast the finish on your models ?
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Old 06-23-2014, 04:49 AM
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Well, we have first experiences. At this moment we didn't have any problems with props or engines. Only exhaust gases at full throtle from 52 ccm gasoline engine were so fast, that fine sand flew through the air. That means, thicker sand would be better, lets say at least 1/5 inch thick. As you maybe can see, we also have grass gratings between sand.

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Old 06-23-2014, 05:28 AM
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Would strongly suggest something like a piece of astroturf or a carpet remnant rather than sand. Also, I would not use a restraint that rotates. That's a good way to lose a finger when the wind gusts while you're tweaking the needles.
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Old 06-23-2014, 09:47 AM
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Astroturf must be thermal resistant. We have sand, because gasoline engine produce quite big amount of oil and carbon black. I'm not afraid about rotating restraints. They can not move easily if wings block them.
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Old 06-27-2014, 05:30 AM
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He means with the wind hits your airplane and turns it. That can definitely happen on a gusty day.

So are you really getting a significant amount of black exhaust residue from gassers? Every one I've ever seen, including mine, runs very cleanly.
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Old 06-27-2014, 12:55 PM
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I can't know what models you fly and how strong winds you have, but in my part of Europe, I haven't seen or heard about anything like that.

After 5-10 minutes adjusting gasoline engine, sand was black. It was some kind mix of deposits and oil.
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Old 06-27-2014, 07:29 PM
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I'm in Texas. I've seen light planes like a Piper Cub get picked up and flipped over on the ground by a gust of wind here. I'd be nervous about a stand that could turn around its middle like that too if the plane wasn't centered. I can't see exactly how the design works, but if uneven pressure from an engine running up can turn it, it only takes an absent minded grab to cause a prop injury. Have you seen the wooden plane stands that are common at flying fields in the US? They are perfect for starting and adjusting the smaller planes and can be turned to deal with any wind direction. The two advantages to a wooden stand is that it raises the plane up so you can stand up while working on it, and it won't turn or move once you've set it the way you want it.
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Old 06-30-2014, 04:42 AM
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Now get that off the ground and put in on a table. The table has to be big enough to allow your airplanes gear to set on. Solves all the issues no sand, won't rotate, high enough off the ground that there shouldn't be any residue.
What kind of oil are you guys running? I run a synthetic oil at 40 to 1. My airplanes stay clean and would not leave a mark in the grass
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Old 06-30-2014, 07:18 AM
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The device is well accepted among modellers. The rotation is an advantage, because device adjusts to the model, and not vice versa. Rotating propeller high on the table is maybe more dangerous. Sufficiently thick sand won't cause any problem.
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Old 06-30-2014, 09:07 AM
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How does the device rotating help adjust to the model? I've belonged to 4 clubs in my flying career they all had tables. But it's whatever works for you.... Good flyin to ya
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Old 07-01-2014, 06:19 AM
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Sand would be my last choice for anything in the vicinity of a running engine out alone one with a prop blasting air over it. A starting table is by far a better and safer choice.
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Old 07-02-2014, 07:52 AM
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We've answered the question, but the OP has already decided he knows what's best. Hopefully no one will be injured by the rotating stand and hopefully no engines will be ruined by the sand.
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