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Old 04-01-2019, 12:07 PM
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Restraining a 40%

What's the preferred method of restraining a 40% plane with a DA200? I've used one of these with DA70s and seen them used for DA120s and such.

https://www.valleyviewrc.com/safe-t-airplane-holder

However, I'm not trusting that to hold back a DA200 with upwards of 80lbs of thrust. I'm not even sure I like holding it by the stabs with legs or a rope since it might damage the stab or rudder.

What's the safest restraint that won't damage the airframe?
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Old 04-01-2019, 01:45 PM
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T post with pool noodles at our field
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Old 04-01-2019, 02:43 PM
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Anyone who cares about their plane should not do full power runups with only the stabs holding things. If one does need to do it, I'd suggest the wing posts seen above PLUS standing in front of the stabs.

Quick blips of throttle are one thing, but letting these big engines gather up their full static thrust is just asking for plane damage, like dented leading edges....or worse!

I start mine (DA200) with a fold-down tail restraint, then stand over that only to warm it up and clear the throttle. Again, these are just quick blips, not full power.
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Old 04-01-2019, 03:33 PM
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Yes, that's why I was asking. I didn't think just holding via the stabs was a good idea. Feels like it's asking for damage when all that static thrust kicks in. Plus, I've heard of the U restraints pulling out with bigger motors.

Note, the only time I would go to full throttle on the ground for more than a few seconds is when I'm tuning things. Following Terry's method (https://www.flyinggiants.com/forums/...d.php?t=194009), there might be 10 seconds at full throttle to check the high needle.

Once I have it tuned, I just want something that prevents injury to me or the plane if the throttle was accidentally high at startup.

Unfortunately, my field has nothing in the way of restraints for large planes, so I need to bring something with me.
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Old 04-01-2019, 03:38 PM
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Festivus,

That looks like a permanent setup. My field probably wouldn't let me do that. I will look into something portable and safe that holds back the wings and the stabs.

Also, I see you have a rolling chicken stick. I'm still kicking myself for not pulling the trigger on one when they were still available. I'm using a paint roller now. It works, but I think the rolling stick is the better way to go.

Dave
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Old 04-01-2019, 05:04 PM
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Most plane restraints are designed for starting up, not full throttle restraints. I use a tail restraint similar to the one posted from Valley View but for full throttle such as tuning I also have tie backs for the wings. Basically the wing restraints (tie backs) are 5/8" ropes through copper tube insulators and are attached to two utility anchors three feet in the ground. My 46% Pitts with a Valach 170 turning a 34x10 pulled the tail restraint out of the ground at less than half throttle so I had to do something different.
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Old 04-01-2019, 05:19 PM
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Yes I poured that concrete slab it's almost 8 in thick so the word permanent fits real well the T pose can be moved they don't have to be permanent you could drive a couple of t-post in the ground and put pool noodles over it and have your own little area I don't think anybody would have a problem with that if it was over toward the end and out of everybody else's way that's where I put our gas section is at the end of all of us used to be nitro plane stands now people put the electric planes on them.


Take a day off during the week, get a couple friends quickly dig hole insert rebar mix concrete and leave, what are they going to do pick it up and move it.
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Last edited by Festivus; 04-01-2019 at 11:06 PM.
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Old 04-11-2019, 09:30 AM
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i only do run ups with 2 people, one on each wing, with legs close to fuse as possible where there are no posts as above.
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Old 04-11-2019, 10:55 AM
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We have these at my club. When we renovated our flight line 6 or 7 years ago we sunk steel tube into the concrete pads that are starting stations on either side of our entrance to the runway. The tube is flush with the concrete and the extended tubes slide into those. There are 2 positions on the right side post to allow it to be narrower... say 30% and under and the outside position for 35% up.

Each upper tube has a piece of roll cage padding on it. This is similar but much heavier than a pool noodle but similar material so that there is more padding on the "driver side making it very gentle for start ups.

There is also chain link fencing between the pilot starting the plane and the flying positions to provide some barrier to and errant prop or spinner.

Some run up there planes against them... I do not but they seem to incur no damage on the 70cc and under.


I replace the padding on them once a year. We also have the same set up on a tuning station that is well away from the pits and flight line for extended tuning and set up.
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