Hollmann HA-2M Sportster

Brent,

I was having the same problem as you. I think it just a slow download of the pictures.
Yesterday I couldn't see the pictures but had to go answer the phone, when I got back the pics had downloaded, I assume its just a slow download. Mine is quite fast on all other posts just this one is a bit slow.
 
After post 46, I switched to photo bucket linking for posted photos. The previous photos are stored, evidently on this website, but the photos after P46 are stored on Photo Bucket, and a link on this website takes you to the photos. I did this for better photo quality and photo size. I wanted people to be able to see the finer details of how parts actually go together. Knowing how I wish I had detailed photos of how the installed parts should look… I guess the linking of the photos causes them to load slower over some connections. So click on the thread, go get something to eat and when you come back, you should be able to see progress… :)
 
Hi Cortland,

IMHO, I don't think you need to worry about landing with a castering nose wheel that somehow might turn out of track with the direction of your landing track.

Because your specific nose wheel axle and center of mass of the wheel assembly is behind the vertical turning point during ground operations, the wheel will track true and straight in a forward direction. During the flair before landing, the nose wheel will keep itself centered and inline with the keel because the vertical line that runs through the vertical swivel point is tilted back allowing gravity to center the nose wheel. The next time you're at the market, take your shopping cart, lift the nose up and watch how the two nose wheels automatically center. The action and physics apply. Take the same cart, lift the nose and walk forward. Then while in forward motion, lower the nose and as soon as the wheels contact the floor, see if the cart turns in one direction.

As far as the centering springs, most aircraft that I know of that have castering nosewheels and use differential braking don't have centering springs. The nose wheels are allowed to caster 360 degrees like a shopping cart. The Grumman Tiger is one aircraft that I can think of off the cuff that has the previous mentioned nose wheel set up, and it works very well. The benefit of using differential braking steering is for very small turning radius. One can lock up one main wheel by stepping on that brake and pivot around the same. If there is a swivel stop on the nosewheel assembly, then one could not pivot effectively around that one locked up wheel.

Come to think of it now, Vance's Predator Gyroplane also has a full swiveling nosewheel and differental braking. He should comment on his experiences too.

Wayne
 
The Grumman series, Traveler, Cheetah, Tiger, and the two seater's have a limit of ninety degrees left and right. The Diamond aircraft series are limited to sixty degrees. The reason for the limitation is to keep the nose wheel from swinging into the propeller arc.
 
360 degrees with no springs or index scheme

360 degrees with no springs or index scheme

The Predator nose wheel swivels 360 degrees without any kind of index and as long as I keep grease on the surface it dampens just fine.

It actually uses a rotor head with the same double row ball bearing.

At one point the pivot assembly became worn and I use a piece of plastic tape to make up for the wear.

When it did shimmy because of wear it didn’t cause any problems, it just felt like it would eventually come apart. She was still completely controllable.

She has over 750 hours on her and well over 2,000 landings.

Thank you, Vance
 
The fire wall is rough mounted. Thank you Mr Dremmel, you cut into stainless steel fire wall like nothing doing! Next step is to install the lower aluminum panel and 60 to 100 rivets into those panels… then get to work on seat mounts, instrument panel, and the control sticks.

IMGP9184.jpg
 
It's starting to come together, good job!
 
The current weights as of now are 38.5 pounds at the nose wheel, 55.5 pounds on the passenger side, and 55.0 on the pilot side. But I weighed it with 6 clamps that I forgot to remove that weight about 4 pounds. So well call it 145 pounds. Complete weight without the engine or rotors is supposed to be 313 Pounds. So I’m about ½ done per the weights.
IMGP9201.jpg
 
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Cortland,

What are you using to cut your sheet metal? From the pictures the cuts look very clean!
 
Hi Cortland,

Great progress! What rotorblades are you going to use? Are you going to build a set of 9" cord Hollmann HA-28s or use 8.5" Sportcopter blades?

Thanks,

Wayne
 
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