Tailskid and lockable tailwheel

[greybeard]

Dear gentlemen,

Some early WWII fighters (e.g. Morane 406, I-16, Ki-27) still have the typical WWI tailskid in lieu of the more modern tailwheel. Beyond reasons of this choice, I wonder if it could be considered, from a physical and practical point of view, more similar to a swivelling or locked tailwheel. I guess that its behaviour should be different on grass airfields in respect of paved runways (given that it was suitable also for these latter), but just can't figure how much it could keep takeoff run straight (also avoiding ground loop) in respect to a locked tailwheel. Maybe a silly question, but I'm curious since I never flew in RL an aicraft with tailskid.

Cheers,
GB

 

[FLYBOYJ]

once you start moving you'll maintain directional control with slight brake and rudder

 

[gumbyk]

How much directional control a skid provides depends a lot on what type of skid it is.
The Tiger Moth in my avatar has a 'spoon' shaped skid, which provides some control mainly because of the drag that comes from it. The Tiger has no brakes, so this, and the rudder are the only directional control you have on the ground. The spoon is attached to, and moves with the rudder so is steerable, although not very effective. If you are travelling slowly and need to change direction, you need to add power to get any authority from the rudder (it is very counter-intuitive when heading for an obstacle to use more power to avoid it!)

WW1 types typically had non-steerable skids with a 'blade' fitted vertically which dug in to the ground and provided a lot of stability on the ground, but also a lot of drag. To get these aircraft to turn, you need to put in full rudder, forward elevator (to take the weight off the skid) and a burst of power. I know operators who have removed, or ground down the blades to make taxiing easier. Your blade won't last long if you land on seal, even grass airfields tend to wear them fairly quickly.

Either way, both types give fairly good control for take-off, especially given that the tail comes up pretty quickly on take-off. As Flyboy mentioned, its mainly the rudder (and maybe brake on more powerful aircraft) that you use for directional control.

 

[greybeard]

Thank you very much for your competent replies, and especially gumbyk for his articulate description (I just don't know what he means for "seal"). Also, I was surprised by steerable tailskid: I didn't know even existence of this kind of device.

 

[GrauGeist]

...(I just don't know what he means for "seal")...

Chip-seal...like hardpan, it's coated & compacted gravel unlike Asphalt or Concrete.