Is the "step" necessary?

klovning · #1 09-18-2009, 03:17 PM

I'm buliding an 8A and I'd like to omit putting the step in - I've heard people have had problems with it cracking. I think it somewhat interferes with the rudder cables in a 8A.

I can carry a little step stool (I got from Bed Bath and Beyond - holds 300lbs and folds flat as a pancake) and I'd just like to know from the crowd if omitting the step will render the plane less than desireable.

pauldan181 · #2 09-18-2009, 06:09 PM

It's nice to have and I use it in my 8A. I don't think you're going to like hauling a stool around.

I'm not sure where they crack, mine's been fine but I'm pretty gentle with it and don't jump on it. I had heard about rudder cable interference so I mounted it as low as possible and the cable just misses it when tight. I wrapped the tube portion with some UHMW tape and at last inspection there were no issues.

Paul Danclovic
Jamestown NC
RV-8A N181SB

videobobk · #3 09-19-2009, 08:24 AM

This may just be all theory, but I believe the cracking is due to stresses built up during welding. If an area cools too fast, it becomes too brittle. If I were building again, I would have the steps annealed. My father was an aircraft welder in the acetylene days and took great pains to make sure cooling was slow and even. Today's MIG welding heats a smaller area, cools quickly, and concentrates the stresses and brittleness. Just a theory...

Bob Kely

gasman · #4 09-19-2009, 09:01 AM

Bob has this one right.........

As you place your weight on the step, the outside weld tries to pull apart. But it will hold because you are not flexing it. But the inner (lower) weld is trying to hold a compression load. And due to the fact that the tube step is hollow, it will flex at the lower part of the inner weld. The step should break at the lower edge of the weld out about 1/16".

If you did anneal this lower weld on the tubing side, this should solve this problem.

Very few of the steps in service have broken. So it must also be the way that the step is used. Never walk forward off of the wing without setting your foot on the step. Don't step down and expect the step to catch your weight. You triple the load that the step will see.

BoilermakerRV · #5 09-19-2009, 09:28 AM

Let me throw a twist in this discussion. From the perspective of ease of entry. I'm about 5' 7" (170 cm). How much more difficult would it be to enter and exit the RV-7A without the step.

Thanks!

gasman · #6 09-19-2009, 10:01 AM

You would not like it after a while. Go find a 7A and try it. Don't forget your passengers......

BoilermakerRV · #7 09-19-2009, 10:20 AM

Quote:

Originally Posted by gasman

You would not like it after a while. Go find a 7A and try it. Don't forget your passengers......

That's what I thought. I had planned on putting the step on both sides.

Webb · #8 09-19-2009, 10:36 AM

It also depends on how old you are - 18 up and down no biggie, 68 and and well.....

Also, risk of damage IMHO is greater without it.

I also make sure I step gently onto the steps instead of just "land" on it.

Steve Ashby · #9 09-19-2009, 12:37 PM

Jason,
It is good to see another 8A in the neighborhood. Please give me a call. I would love to compare notes. A few months ago I was making the same decision as you and elected to go with the step. The jump onto the wing is just too far for an 8A and a step stool seemed like just too much trouble for me. Installing the step was not any real problem and I am glad I did it. I am now working on the canopy and hope to fly next summer.
Cheers,

Bob Axsom · #10 09-19-2009, 12:58 PM

I have an RV-6A upon whick I installed the steps permanently. 3 years later I carefully drilled out the rivets, cut holes in the baggage compartment floor for inner mounting bolt access, made cover plates for the access holes, made nut plates with many platenuts to accept #8 flathead stainless steel screw mounting in place of the original rivets, countersunk the holes in the external mounting plate for the screw heads to make a removable step installationm dimpled the fuselage skin at the mounting screw location and made cover plates for the step hole with dimpled mounting screw locations. When I prepare the plane for a race I remove the steps and install cover plates I can step up on the wing and get up there. I cary along a small plastic step stool for my wife to get in. Other planes have greater distance from the ground to the top of the wing but if you want to do it you can work out the logistics to get it done like stowing the accommodating stepstool under the plane.

In actual testing I found the top speed was not measurably increased bu removing the steps. I still go through the change for every race because there has to be some small increase in speed resulting from removing the steps. When we travel I put them back on and the comfort of getting in and out is elevated to "wonderful" status.

So here is a suggestion, make the steps a removable installation and you can decide later which you like best. You might think about this kind of assembly - screws in place of rivets - in other places to make the airplane more maintainable.

As for the age thing - I will be 73 in a little over a month and though in my youth I was 6'2" I'm now bent and compress to closer to 6'. I do a set of 100 or more push-ups every day as a part of an exercise program I began at 26 when JFK initiated a fitness program in the U.S. Age does not have to be a limiting factor in the step decision.

Bob Axsom