Hard runways for Cozy

[Spodman]

I've seen references to avoiding rough runways, and others saying only use hard runways. I understand the issue is mainly FOD to the prop, but also a fairly brisk landing speed.

 

If I want to base a Cozy at a nice, long, grass strip am I asking for trouble? Or is it just not possible?

[LargePrime]

the cozy is not well suited for the typical grass strip.

 

You might want to look at infinity aerospace for some suggestions.

[Marc Zeitlin]

Originally posted by Spodman

I've seen references to avoiding rough runways, and others saying only use hard runways. I understand the issue is mainly FOD to the prop, but also a fairly brisk landing speed.

 

If I want to base a Cozy at a nice, long, grass strip am I asking for trouble? Or is it just not possible?

There are a number of issues.

 

As you say, damage to the prop is one, but that can occur on crappy hard surface runways with garbage thrown up by the nosegear as well as on grass/sod/dirt. Some people will take off and taxi with the landing brake down on crappy surfaces to prevent this, and then retract it upon ground breaking.

 

Another is the small size of the wheels - 5.00x5 are a bit small for lumpy surfaces. Doable, but not optimal. Some people have installed 6.00x6 main wheels, but this will entail larger and higher wheel pants, as well as more drag and a slight speed loss, as well as a minor adjustment in main strut length to account for the larger wheels. Eminently doable.

 

Another issue is the marginal strength of the stock nose retraction mechanism. It just can't take much of a beating. With one of the electrical nose lifts, I don't think this would be a problem, as long as the casting area is beefed up with the normal set of modifications.

 

I would also recommend setting the normal ground attitude of the plane a degree or two nose up, rather than at 0, to facilitate lifting the nose at slower speeds.

 

There are some V.E. (Nigel Field, for one, IIRC) and other canard pilots that do/have operated from grass fields - even some small ones, but it's not very common. With larger mains, an electric nose, higher ground incidence, and judicious landing brake usage, a smooth grass runway should be no problem.

 

I've operated off of a couple of pretty ratty paved runways (Jaffrey, NH for one) and the COZY tends to bounce a lot, but even with tight wheel pants on 5.00x5 wheels and the stock nose mechanism, it doesn't seem to be a major problem. I haven't hit any large potholes, though.

[lacoss]

has anyone tried using a small half fender on the front wheel to help stop debris from projecting into to prop arc ? I know it would take a little more room in the nose when it iis retracted, but would it work?

[Wayne Hicks]

There are many Long EZs who fly with slicks on the nose tire (i.e., a tire without grooves). Slicks minimize the amount of debris that would otherwise be collected in the grooves and thrown out when the tire gets up to speed.

 

There are a few who fly successfully with a nose fender, too.

 

As for operating on grass fields, I personally feel a limiting factor is the nose tire itself, not just the mains. The nose tires we use are skinny, small diameter, which all translates to higher loads being applid to a much smaller contact patch with the ground.

 

Soft field takeoff technique is not as effective on canard airplanes as it would otherwise be on non-canard aircraft. Assuming your typical tricycle gear Cherokee (T-tails need not apply), you yank back on the controls and use the prop wash to rotate nose up, thus taking some of the weight off the nosewheel.

 

We can't do that in our canards. The weight on the nosewheel stays basically the same until the airspeed is enough for the canard to create lift. Those canardians that fly off grass strips will tell you that tire drag limits acceleration. The drag on the nose tire often ends up pulling the strut aft, lowering the nose, lowering the canard's angle of attack, and exacerbating the whole take-off deal. It takes lots more runway to get the plane going fast enough to get the canard flying.

 

And I don't know about the rest of you, but that nose strut we have is not very robust. It is awfully skinny and is very susceptible to damage if it hits something too hard. Just ask the Cozy III owner who tried to take off from Tangier Island's (KTGI) infamous roller-coaster runway. And just ask Jack Wilhelmson what happens to the nose strut when you inadvertently taxi the nosewheel into a deep tie-down hole.

 

So, Can you operate on grass strips? Depends on the strip itself, length, and your intestinal fortitude. Can you operate of rough strips? You can...at least once anyway.

 

Wayne Hicks

[No4]

This is what they put on the nose gear of 737's when operating into rough strips in Canada, to prevent stone damage to engines and airframe.

[Spodman]

Thanks for the information. I love No 4's stoneguard, makes me want to buy plans just to pencil it in...

 

Coincidentally, I'm reading Vera Rollo's biography of Bert Rutan at the moment (not bad by the way, if a bit "magazine-ish"). In it she says:

 

Burt decided to develop a grass field/rough field capabilty for the Long-EZ so it could be flown anywhere.

 

Typically, after designing and installing a spring-loaded nose gear "shock strut" and larger main tires on the Long-EZ, Burt flew it into a typical grass field and tested the landing gear. He then announced that with the new modifications, the plan was approved for operation from average grass fields.

 

Anybody know if this modification made it onto any aircraft, or is it still available? Anybody tried it on a Cozy?

 

I also note the following from Cozy Newsletter #63.

 

First of all, the main wheels are outside of the propellor arc, so the only question is the nosewheel... ...In 20 years of flying pushers, and landing on many different runways, and taxiing over a fair amount of debris, only once did I pick up an AN3 bolt which left its impression on my prop. That was when I used a burst of throttle on a dirty taxiway at Chino. I should have known better.

[Marc Zeitlin]

Originally posted by Spodman

Burt decided to develop a grass field/rough field capabilty for the Long-EZ so it could be flown anywhere.

 

Anybody know if this modification made it onto any aircraft, or is it still available? Anybody tried it on a Cozy?

 

See:

 

http://www.ez.org/cp25-p3.htm

 

This is what the COZY has. Remember, the COZY weighs 600 lb. more than the L.E., which is why 6.00x6 tires and the other stuff would be better for the COZY on grass fields. Also, note that gravel and rough fields were still not approved - just average grass.

[jperryfly]

I think most of us operate with the spring nose strut. I tried my Long (IO-320) on the grass field at Indiantown, Fl and had a hard time getting off. It is 6,000' and I used most of it trying to get off. Finally had to offload 20gal of gas and try the next morn. A bump helped get my nose up. Once the nose was up it was no problem. An observer noted that my nose strut was pulling way back due to drag of "average grass". I have since put in the short yellow 1800# spring and preloaded it to 400# and I've gone back to regular 5.00x5 tires. I had the long yellow spring in before and it was hardly preloaded at all. I haven't tried this yet but I think it will help alot. I'm moving to an airpark where they have not yet invested in asphalt, but it is a better grass field, although shorter, 3100'.

On the AeroCanard I'm building I have 15-6.00x6 tires and the Wilhelmson nose lift which has the yellow spring loaded to 400# so I hope to be OK.