Nosediving Like Crazy

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MoMoney$$$;)0)
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Nosediving Like Crazy

Post by MoMoney$$$;)0) » February 14th, 2019, 6:18 pm

Hey fellow users,
I need some help quickly, as I am having last minute problems of the glider as soon as it is launched and it nosedives fast and hard as soon as it is launched. I used the freedom flight model kit, and it was launched pretty accurately and has a nice slow glide, so I really need some help, as I have already tried balancing it so the center of gravity is in the middle, but what else should I do.
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Re: Nosediving Like Crazy

Post by builderguy135 » February 14th, 2019, 6:22 pm

MoMoney$$$;)0) wrote:Hey fellow users,
I need some help quickly, as I am having last minute problems of the glider as soon as it is launched and it nosedives fast and hard as soon as it is launched. I used the freedom flight model kit, and it was launched pretty accurately and has a nice slow glide, so I really need some help, as I have already tried balancing it so the center of gravity is in the middle, but what else should I do.
Try some up elevator.
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Re: Nosediving Like Crazy

Post by bjt4888 » February 14th, 2019, 7:37 pm

Mo,

I believe that Builderguy has given you the correct starting point to resolve your issue. If the wing on the FF glider is removable and attached with tape to the fuselage, you can insert a shim under the front of this wing attachment to effectively increase decalage angle.1/32” shim is probably a good starting point.

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Re: Nosediving Like Crazy

Post by fifty_missions » February 15th, 2019, 8:07 am

Though this sounds like an emergency, there is another approach. Here are the choices. The first two are typical. the third is the dark horse.

1) Leading edge of wing flying to low and needs to be raised as described previously in other posts..

2) Raise the trailing edge of the stabilizer to bring the nose up. Add clay to nose to cure any stall. Downside is that it adds mass to the glider but will definitely work. The up elevator (very slight) will help keep the nose from dropping.

3) Remove some clay from the nose until glider stalls then add down elevator in slight increments to remove stall. This has a tendency to "clean" the glider to allow lower power because there is less drag while launching.

There are other options and techniques to consider. Some FAI and AMA indoor gliders get launched via "bunt". They are designed to launch vertically and, in some cases, beyond the vertical (say 110+ degrees) and the launch flight curves forward into transition. You may have inadvertently created a glider that functions like this.

The FF kit has always been notoriously short coupled. The span from trailing edge of the wing to the leading edge of the stabilizer is too short. This causes pitch sensitivities (nose up/nose down. Any slight incidence change (wing or stab) is quickly aggravated with the speed of the launch. Check to see if either the wing or the stabilizer can move along the fuselage.

Also check the trailing edge of the stabilizer. If sanded too thin (>.015"), it may flex to its weaker side which may be creating a down elevator effect.

Post what results you get and what variable you corrected to cure the issue.

Good Luck,
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