Steerable Tailskids

[PeterFokDVII]

I found the Old Rhinebeck steerable skid photos. It was modified after the plane was flying, not when first built like I thought. The skid set up is not like their DR1's, which looks like it would be lighter. The D.VII's has a "dual horn" connected by springs, which pivots only the metal skid plate on the bottom of the skid, not the lower wooden portion of the skid itself. But this setup requires more metal hardware and like I said, looks heavier.

I can't post the photos for about a week. My hard drive is going bad, and I'm installing another one this week. Right now, I have no Photoshop or scanner software working.

As far as how the skid mounts at the top. On the D.VII, it was built originally to pivot, so it could take the directional changes on the skid when landing. The hinge that it mounted to on the bottom of the last fuselage upright member, allowed it to turn left & right (as well as pivot for shock absorption), but not fall out. At the top, it had a steel ring, connected to the top left & right sides of the fuselage by steel braided cables and springs (one set on each side), plus an unsprung loop of braided cable that was for safety in case the springs broke, to keep the skid from completely collapsing. So the top sort of "floated" originally anyway. This would probably already be enough slack movement to allow the skid to steer with the addition of the steering plate & springs hooked to the rudder horns. To get more movement, just increase the lengths of the top springs/cables, just make sure the movement is limited to keep the top of the skid from hitting the fuselage at full turn. (I have good photos of this too, from the uncovered Paris Museum's D.VII, and I'll send those too when I can).

To simplify your skid structure and save tail weight, I think you should just hire a couple of helpers to follow you around to "pivot your tail" for you.......

....................I'll post the photos soon.............Pete

[Jim Bruton]

Thanks Pete,

I understand about hard drive issues- when you can, I'll love seeing the photos. The ones you posted already help a lot.

Best,

Jim

[Major Larabee]

Originally Posted by Nick

This is the arrangement on the Sopwith Snipe. You can see the Tailskid fork rotates inside the Sternpost and steers the tailskid.

That a very usefull pic, we are just looking at changing the tail skid on our BE2 to a stearable one. Tell me do the bungee's rotate with the skid at the top or is the top attachment fixed, if you see what i mean. I was worried that if the bungee's canot rotate it would restict the movement of the skid??

[Nick]

The bungees does not rotate where attached to the sternpost. The U'bolt attached that end is larger as a compression post slides up & down through the centre of it. The empennage trim is adjusted this way with a large lever also hinged in the centre of the sternpost. I'd add another picture but it took me all night to post the last one!!! I'll get the hang of it eventually!

[snipe]

Originally Posted by Nick

The bungees does not rotate where attached to the sternpost. The U'bolt attached that end is larger as a compression post slides up & down through the centre of it. The empennage trim is adjusted this way with a large lever also hinged in the centre of the sternpost. I'd add another picture but it took me all night to post the last one!!! I'll get the hang of it eventually!

This project has my interest! Who is building it, where, which plans, power plant, is there a thread on any forum?

(Used to live in Melbourne)

[Nick]

I'm building it. Using both the original plans and Jim Kiger's. Using a W670 radial. I gave up trying to find a Bentley. Not only, not available but out of my price league!
My appologies to Jim , we're "steering" off his thread here

[brinesharks]

I can also confirm that the Sopwith Triplane has a steerable tail skid. It's not as robust as on Nick's Snipe though. It's a wood skid with a large cut out for the bungees then a metal strap is wrapped around the end to hold tail skid and bungees together. It is interested to note that the cables that steer the skid go directly to the rudder bar (through the fabric of the fuselage near the tail). If you were designing one from scratch, I would copy the Snipe at it is obviously stronger than the earlier Sopwith types.

[Jeff Brooks]

I have some pictures of the Fokker at Rhinebeck.
the first is looking up at the torque tube on the rudder. you can see the tailskid pivot point in the lower left.


this other photo is looking downward at the tailskid, and you can see the springs that attach to the arms on the rudder torque tube to the end of the tailskid.


Initally, I was going to use the same idea, but instead of attaching the springs to the end of the tailskid, I was going to attach the spring to the pivot point of the tailskid.

[Jim Bruton]

the more photos, the better- thanks Jeff!