Grass airstrips

[stevedrew]

Forum,

I want to know whether the undercarriage of WW1 aircraft NEEDED to operate from grass airstrips or not.

Of course, airstrips could not be constructed in a short space of time during war time. There was also a lack of materials and aerodrome locations were under fire some (if not all) of the time.

Post war, and even in present days (for those aircraft surviving in flyable condition and replicas), WW1 aircraft are operated from grass strips.

Is this to give them the authentic appearance of a WW1 aerodrome? Is it to give pilots a "softer" landing in the event of a "difficult" approach? Or is it, for whatever reason, impractical to operate from a concrete strip?

Any help would be greatfully accepted.

Steve Drew

[Rick]

Perhaps to save wear and tear on the tail skid?!!?!??!?!??? R.

[Dan_San_Abbott]

SteveDrew:
Aircraft without brakes and tailskid would have serious troubles in landing on concrete. First all during offense when squadrons/Jastas were mobile mowing the grass and filling holes was about as much time was allowed prior to operations. During WW2 our squadrons operated off grass fields until the Army engineers got the time to lay down pierced steel landing matts. On early aircraft the tailskid acted as the brake.
Blue skies,
Dan-san

[MikeW]

Steve,

Droglandt had rolled ash runways, properly laid out like a St. Andrews Cross. This was probably due to a high water table rather than any consideration of what was best for a 1917/18 aeroplane!


Mike

[wolfenbill]

Steve, all the factors previously mentioned influenced the necessity of having a grass strip field. Grass fields provide much more rolling resistance than concrete hence it acts as a brake for all those aircraft who had none. And if you see a tailskid touch down on a strip with lots of dirt, you'll see dirt fly just as if a big plow was moving through, which in essence, is what is happening. Tailwheels, brakes, etc. came later, allowing the use of concrete. Of course the downside of a grass strip is when it is subjected to a large amount of rainfall. It gets mighty soft........not a problem for concrete.

[timjnf]

My understanding of WWI aerodromes is that most did not have "runways" but were big fields; allowing landings to, for the most part, always be directly into the wind; so crosswinds probably were not a problem for them.

However, if crosswinds are an issue, grass is better than paved if the touch down isn't properly aligned, or if the crosswind is near the max crosswind component for the aircraft; especially with tail draggers.

And if the unpaved surface isn't rough it causes less overall wear and tear on everything related to the landing gear.

[ONEALM]

Steve -

I can't add much more to this, but can say I fly a '46 Cub and the brakes are very, very weak. Almost to the point of ineffectiveness. That was designed that way though to keep you from doing something silly like taxiing fast and slammin on the brakes. Effective brakes would have you on your back in a hurry.

I land on hard surfaces just about every time I go out and only ever use the brakes to turn tightly when taxiing slowly. I try to never use them to slow myself down and it's very, very rare that I need them. Obviously landing rollouts are longer on pavement and the reaction of the airplane during rollout is much more squirrely. If you are not straight on touchdown and not on top of the rudder, you'll be going for a ride off the side of the runway in a big hurry.

For all the reasons stated by Dan, Wolfenbill and others, I much prefer grass.

Mike

[Rick]

Mike, I would assume that your '46 cub has a tail wheel (as opposed to a tail skid) !! R.

Another consideration is that a tailwheel can only roll along one axis. A skid on pavement will slide in any direction more or less equally. Thus, on pavement with a skid if for any reason the tail starts to wag there is very little if any restoring force. Tailskids and concrete are a very bad idea. Roughly equivalent to pushing a shoping card backwards at high speed.

Kevin

[timjnf]

There are actually several types of tail wheels.

Some tailwheels are non-locking, full castoring, and provided very little help in directional control; and might actually provide less directional control than a skid while off pavement.

More common, is the non-locking, steerable, castoring type.
There is a detent the wheel mechanism falls into that links the wheel to the rudder via some springs. In this mode it is steerable to about 30 degrees in either direction and does a lot to help you steer as rudder authority weaker as you slow. But if there is weight on the wheel, while taxiing for instance, and you turn hard enough, the wheel automatically exits the detent (it is simply forced out of it from the sideways load) and becomes free castoring; which allows you to swing the aircraft around on a dime. Move forward and it falls ack into the detent.
Both the Citabria and 1948 C-170 I fly have this type of tail wheel.
I've never flown an aircraft with a tailskid.