The A2A Simulations Community

Dudley,
I had a real world flying experience yesterday and I wanted some of your world class advice or insight. I was flying the Diamond DA-20 C-1 as I have done dozens of times. The whole flight was normal and everything went great right up until I touched down. The mains tocued down softly and as the nose came down, the whole aircraft started to shake violently. Enough that I thought things inside were going to break off. I figured maybe it was a blown tire. So thinking that things were fine before the nose went down, I went back to the way things were and pulled back to get pressure off the nose wheel. I didn't let on to my passenger (mom as a matter of fact!) that I was concerned about anything and I kept the plane under control. I taxied off the active and got to a nearby spot on the ramp. The tires were fine. My dad who was watching near by said that when he saw us touch town the, nosewheel began to shimmy and he could hear it from quite a distance away. Do you have any idea what could have caused that? And was getting pressure off the nose a good thing to do? I've always been taught if you do something and it has a negative result, put things back the way they were.

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All the best - Flyboy4612
Private pilot/tail-dragger endorsed

I'm not Dudley, but I have experience with the Katana. The problem is the free castoring nosewheel. If you touchdown with any amount of drift, you risk shimmying the nose wheel, just like on a Cessna with a bad shimmy damper. The best way to fix it is to do like you did, take the weight off the nose for a moment and then relax the controls and allow the nosewheel to take the weight again gradually. As long as it doesn't do it again when you relax the controls, then that's the problem. If you continue to have a vibration, it's either a blown tire, or you've got an imbalance for some reason and the tire and wheel need to be inspected.

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I knew it was nothing major, I just didn't enjoy the experience. The same thing happened a couple times when I was flying the Cessna 177 Cardinal as well. It rarely happens but I guess just like in the olympics, sometimes you just don't stick the landing!

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All the best - Flyboy4612
Private pilot/tail-dragger endorsed

CAP flyer is correct. I've not flown the Katana and am not familiar with the nosewheel design but my guess would be a shimmy dampner. This was a real problem on Cessnas used for training, especially 150's and 172's back when. The solution when this happens is to get the flaps up, raise the nosewheel a bit to take the pressure off Use a bit of power if you need it and have the room, then ease the nose down gently using subtle rudder pressure for directional control.
Dudley Henriques

Dudley, there's no shimmy damper on the Katana (or any of the Diamond pistons for that fact). It's a fully free-castoring wheel. Makes it a light gear, but makes things interesting if it's not streamlining correctly (had that happen on my second flight in one, we wondered why it kept pulling to the right (despite me being the heavier pilot) until we landed and the nose gear removed all doubt when we swerved pretty hard as the nose wheel touched and then was dragged back in line.

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We used to get this in the Yankees )
D

Sometimes I wonder if Diamond got the idea from the Yankee and Cheetah because the look is very similar, as are the problems.

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I'm in the Eclipse, not the Katana. I doubt if that makes a difference. I know on the Eclipse the nose wheel has a range of 60 degrees. Anyway, thank you both for your replies. I appreciate it.

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All the best - Flyboy4612
Private pilot/tail-dragger endorsed

DA-20C1 is still a Katana, all they did was put a little bigger engine in it and change the name for marketing purposes. The plane I flew was a DA-20C1A that said "Katana C1" on the side of it when it was delivered direct from Canada to our flight club in Denver.

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As an experienced DA20 pilot I will confirm what Chris has stated. It can happen from a few things. A bit of sideways drift from a crosswind or a crab, from placing too much weight on the nose wheel too soon, lack of flare, or even landing on the nose wheel first before the mains, I've even seen it do it with some dirt/grass stuck up there. You did the right thing. I had this happen to me once, scared the crap out of me. I ended up going around. Mind you I was doing a touch and go anyways.

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Our Baron has an occaisonal shimmy problem with the nose wheel, and on rough runways (even paved) it will shimmy (the dampener has been rebuilt four times). Suprisingly, it didn't shimmy on teh grass strips we landed at this summer.

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© 2011 Peter J. Carlson, All Rights Reserved
"O! for a horse with wings!" -William Shakespeare

So even the ones that say Eclipse (this is my ship below) are exactly the same as a Katana C-1 and they just changed the name for marketing?

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All the best - Flyboy4612
Private pilot/tail-dragger endorsed

I think the newest models have had some "sculpting" done to them and they've added glass and diesel options, but it's still an evolution of the same design, not a new model.

The difference between a Katana and an Eclipse is about the same as the difference between a 1969 Cessna 172K and a 2011 Cessna 172S NAV III. There's been a lot changed under the hood, but it's still a Skyhawk.

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That's a good way of looking at it. In those terms it's like comparing a B-17G or one that's a fire bomber. There are some differences but at its core, it's still a B-17.

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All the best - Flyboy4612
Private pilot/tail-dragger endorsed

Actually the difference between the DA20-A1 (80hp rotax) and the DA20-C1 is very small. The wings sweep was changed from 1º to 0.5º to move the center of lift forward, the battery was moved aft to help with the CG with the bigger engine, and the flaps were changed to sloted instead of simple hing.

The difference between the C1 models is; C1 Katana Eclipse same as a C1 changes but interior the same as a A1. C1 Evolution the same as a C1 Katana but striped down of all the and made lighter for flight schools. C1 Eclipse, same as a C1 Katana but intended for private use, added rear windows, and nicer interior.

So nothing changed under the hood. And no difference really between the models.

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