I noticed that, too, last night while reading that issue. I think the reason you don't see Cirri on their backs, is because most, if not all, don't land 'em on grass...Dunno.
 
Cirrus

Out our way we had a Cirrus land on a grass strip. Grass was wet and Cirrus couldn't stop. It ended up in the trees never to fly again :(
 
Looks similar but different.

More RV's flying off of more grass. However looking at the pic the Cirrus tire does look larger and clearly the the trailing fork is at a greater angle, meaning the lower leading edge of the fork is higher above the ground. The Cirrus list a 5.00-5 nose tire it looks bigger in the pic. The mains on the Cirrus is 6.00-6. If you think about it, if the mains dig in it can start the nose to be driven down.

The RV's use a LAMB tire which is even smaller than a true 5.00x5 (width-rim dia). The LAMB's diameter is smaller by several inches (installed inflated).

The Cirrus fork is in line with what Van did with the new mod fork, but still the angle in much flatter. The problem with the Cirrus angle is stability or possible gear shimmy (aka old grocery cart wheel wobble). Also the gear leg is almost constant cross section, top to bottom. Is it stronger? Who knows but it is bigger and more draggy
 
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Same sort of nose gear on Diamond DA20.

diamondov4.jpg
 
cleve_thompson said:
I saw this photo of a Cirrus in the latest AOPA mag and was shocked to see how much its nose gear without fairings etc looked like our RV 9A's. I don't remember seeing a Cirrus on its back maybe because of its size, but it would certainly just as likely to fold the gear as is a RV A model.
Click on the link below to see this amazing resemblance.
Click to expand...

The Cirrus gear is similar looking, but definitely not identical. It uses rubber biscuits (I think like the RV10) and the fork angles down more.

It does fine on grass, although fewer Cirrus drivers land on grass in my experience than RV guys..

I'm not aware of any grass issues or flips, but the nosewheel is somewhat prone to shimmy, with occasional loss of the nose wheel pant.
 
DA20 nosegear

tobinbasford

Same sort of nose gear on Diamond DA20.

The DA20 appears to be quite different... much beefier diameter leg and a greater rake, it has the rubber donuts for suspension and I believe only the lower portion (just the trailing fork) rotates instead of the entire leg.

Interestingly enough the nosegear is also slightly off center.

Stan
 
Yeah, the DA20 is almost completely different, other than the fact that it is free castoring. We have two 20's and a 40 where I work, and I'll get some up close pics if interested. It's a REALLY good design IMHO.
 
cleve_thompson said:
I saw this photo of a Cirrus in the latest AOPA mag and was shocked to see how much its nose gear without fairings etc looked like our RV 9A's. I don't remember seeing a Cirrus on its back maybe because of its size, but it would certainly just as likely to fold the gear as is a RV A model.
Click on the link below to see this amazing resemblance.

http://picasaweb.google.com/cleve3/LittleRiver2ndAnnualRVFlyin/photo#5080117784574197250
Click to expand...
It looks very similar to the RV-10 gear configuration but not the 6-7-9 configuration. At the gear mount point on the engine mount you can see the rubber donuts that are going to be absorbing the shock on that gear. This is very similar to the -10.

I would say the flex of the 6-7-9 gear leg allows for some downward and backward movement of the wheel yoke while the -10 configuration will tend to have the yoke flex upward and backward (just my guess on these movements as I have not really studied the actual movement first hand).

The angle of the yoke appears to be angled up higher on the wheel to allow more ground clearance (this is what is needed for the RV's) and it has a larger tire (again something that is needed in the side by side RV's). It may mean an increase in drag but if it will keep from having thousands or tens of thousands of dollars worth of damage I am going to vote for the increase in drag.
 
cjensen said:
Yeah, the DA20 is almost completely different, other than the fact that it is free castoring. We have two 20's and a 40 where I work, and I'll get some up close pics if interested. It's a REALLY good design IMHO.
Click to expand...

Only thing that annoys me about the DA20 nosegear is it isn't on the centerline! I have this thing about symmetry in airplanes. :rolleyes:
 
A friend of mine was helping me time my mags a couple of days ago and he used to work at a Cirrus timeshare-type operation. He explained that they did maintenance on one Cirrus and while test flying it had an engine fire. The fire melted the donuts on the nose gear and as the pilot put it back down on the runway the nose settled down and of course he had a prop strike.

The donuts are literally carrying the weight of the nose.
 
cleve_thompson said:
I saw this photo of a Cirrus in the latest AOPA mag and was shocked to see how much its nose gear without fairings etc looked like our RV 9A's.
Click to expand...

Nope, they're not the same at all. The Cirrus gear is more sophisticated and has significantly more ground clearance.
 
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