How we grow Sport Rotors

[Master Roda]

I decided to start this thread as a way to answer some questions about Sport Rotors that you may have.

I build the rotors for Sport Copter. I have been for a long time (it seems like). Over the years I have done my best to streamline the system that Jim Vanek built. I've increased the efficiency of the system, and made adjustments that have improved the end product. I don't do it alone. I have a couple of helpers, and they do a fantastic job.

Without letting secrets go I'm going to do my best to describe what actually goes into a set. And maybe answer the question "why do they take so long?".

First, the materials are sourced from manufacturers that can provide documentation that certifies it. If we can't get that, we don't use it. 6061 T6 is what we use for the majority of construction. It was chosen as the best material to extrude and give the longest life for our purpose. The extruded section is scrutinized for any kind of twisting or deformations. The same for the sheet metal skins that comprise the majority of the airfoil. Sometimes the sheet metal has ripples in it due to fact that it came from the end of a roll. We can't help this and you'll sometimes see it in the rotors finish (I hate it).
The components are precision cut and processed (drilling/milling). Then they are weighed and paired for each set to within 2 grams. With each set a traveler is assigned that documents the entire process of manufacture. The weights, lengths, temperature, humidity, and times are all documented.

With a paired set we process the materials through the bonding process. I can't say much about that, but we document the entire process. We also process a small sample through with each set and test it for conformity after the process. This sample is kept as proof of the successful bond. The bond has been tested by independant labs and myself to 5 tons per square inch sheer. If you've ever seen a set of crashed Sport Rotors you'll see that the bond line never breaks (unless the metal tears). We keep a few sets of crashed rotors here at the shop to show customers. Visible proof is always better.

After the bonding process they are finish sanded and re-weighed. This process is also documented. There is actually alot that goes into sanding them. The tips are rounded BY HAND. This job requires alot of skill and patience. That job is handled by one of the helpers and I have never had a hand in that part of the process.

When two sets have been finish sanded I paint them. Before the paint, I seal the bond lines with structural epoxy. Then they are washed and treated with an adhesion promoter. Next I apply the primer, but not just any primer. This primer is an aerospace primer designed for rotors. It passes what they call a whirling arm test. It isn't cheap and it's a pain in the butt. You can't just mix it and spray. It involves a lengthy dwell time and time to topcoat. Finally, when the primer is ready to topcoat, I spray on the white polyurethane topcoat. To accelerate the curing process I heat them up in our large oven at the prescribed temperature and time by the manufacturer of the paint (PPG). Before we built the oven we had to wait weeks to assemble them. The oven was built about 5 years ago.

The hub bars are CNC machined 6061 T6. The other materials are a trade secret. We use all AN and NAS hardware. Everything in the hub is either plated, anodized, or protected in some way. I personally build each one to assure precision and quality. Mistakes at this point are unacceptable. I have implemented a system of checks and balances to assure this.

I assemble the rotor system with an aircraft lubricant to assure everything goes together smoothly and stays protected. The system is balanced (within 1/10 of a gram) , checked for proper pitch and lead/lag positioning. The center barrel is centered with a dial indicator. If it isn't centered perfectly it won't fly well. Again, the process is documented.

FLY!! This is the fun part. Either Jim or myself (or both of us) will test fly the set documenting the conditions of the day and how well the rotors fly overall. We even rate each set. This is important. We know for sure that the set is good before it goes to the customer, and any complaints are usually solved with the customer finding something wrong with their machine.

Finally, I pack the set and ship it. Sometimes the shipping company runs forks into the side of the box and I get to start all over.........

Questions?

[GyroDoug]

Jon,

That is a great job of explaining how much goes into building a set of Rotors. I can't imagine wanting to build my own rotors. I would feel much more comfortable with knowing that such a critical part was built to professional standards. And I have never heard of anyone complaining about the quality of a pair of Sport Copter Rotors, so you must be doing it right. I know your Rotors are a little more expensive than other models available on the market, and we all hope to get a better deal whenever we buy something, but I suspect there is a lot of truth to the adage that you get what you pay for. At least with Sport Copter Rotors, you know you are getting a Rotor that was built to the highest standards and that has a great reputaion. I wish you nothing but continued success with your enterprise.

I do have a question (or two) for you. Is Sport Copter experimenting with tips weights of any kind? Also I seem to remember some talk earlier of experimenting with a wider chord Rotor for larger machines. Can you tell us any more about ither of these topics?

[Master Roda]

Thanks Doug.

Yes, we did some calculating and testing of various tip weights for different diameters and cords. Some diamters don't need tip weights while others have a good amount in them. This came about when I was running our airfoils through a computer program to find if I could change them for the better. Ultimately I came to the conclusion that my Transfoil idea would be best. I havent had time to build them yet due to a huge influx of orders.

The largest cord we make is 9". Jim and I have been talking about trying a 10" cord, but we would need to retool again and that's not possible while I'm in production. The 9" cord has proven to work VERY well on the SCII, and we have sold several sets worldwide. They have tip weights.

Jon

[Mike484]

This is very interesting, and it sure makes you feel better when you know the craftsmanship and care that went into what is keeping you in the air.

[Master Roda]

Tools of the trade for the assembly side of this include a digital protractor that is accurate to 1/100 of a degree. I use this protractor to set the pitch and record the numbers in the document following the set.

After recording the mass weight (and adjusting as necessary) I perform a static balance with a gravity level. It was originally made by Jim and I added a couple of things that make it easier to read.

A laser is used to set the lead/lag point and double checked with an actual string (heavy monofilament). I've found the laser to be perfect for this and made a handtool that can read the laser as a measurement that can be used to adjust the system with extreme precision.

When we go out to track the rotors we usually use a flashlight pointed at the reflectors I install at the bench. Sometimes we can use a mirror (the 5 days a year we get sun) to reflect sunlight. One customer (Ben S.) uses a laser and has reported great results. If you opt to do this, make sure the laser isn't pointed in a direction that can blind anyone.

[Doug S.]

Jon
I have never had a problem with my Sport Rotor blades or my Sportcopter for that matter. And I've always been very pleased and very satisfied with the quality and craftsmanship. Thanks for breaking the process down so we can understand a little better the complexity of the blades and what you go through to give us, the customer the very best.
All I can say to you and Jim is JOB WELL DONE !
When you fly to different types of gyros, I am alway picking out what engineering designs that I like the best. I love Sportcopter rotor heads, your ahead of the game in my opinion.
Thank you for your hard work.
Doug S.

[BEN S]

so you can make like 3 sets a day or so right?





Ben S
(who has put the bonding to the test under ACTUAL field conditions!)

[Master Roda]

Originally Posted by BEN S

so you can make like 3 sets a day or so right?

I wish. I might actually get bored. It takes about a week and a half to two depending on weather and our schedule from start to finish.
The problems arise when I get 5 orders within two days of each other and each customer wants the same lead time. It can't happen, so somebody has to wait. That means the last guy on the list has to wait for the previous orders to be filled before I can start on his. It really sucks but most customers are understanding of the situation.

[i3 roberto]

Master Roda :I know the compllications of building rotorblades and thanks for companies like you have ,its posible fly ,and thanks for this ,I know about ,profesional secrets but do you can share some pictures of you shop or your final product please

[Master Roda]

Originally Posted by Doug S.

Jon
I love Sportcopter rotor heads, your ahead of the game in my opinion.
Doug S.

Thank you Doug. We're working on a new design for the LSA machine that may be adaptable to other machines.

[Master Roda]

Thanks Stan. Yes, I am very proud. I don't do this for my health or money.

[Master Roda]

So, what do we do with all of the waste materials?

The chemicals are taken by a company that processes it back into reusable product or disposed of entirely. It's isn't cheap, but we want to comply with the laws and not pollute our ground or water.
The aluminum is recycled.
The unused paint is allowed to harden, then declassified as hazardous waste according to the state.
Acetone is recovered from all operations and recycled in a recycler that I built years ago.

[RotoPlane]

I'm not at all surprised Jon, that you build your rotors with care, documentation and testing…..but it's nice to see it here in print .
It is also nice to have someone like you contribute some of your expertise to this forum. Thank you!

[bmoore2156]

Jon,
How long do you save the test samples for each set of rotors?
Are you required to save them by law?
Nice article.
Brad

[Master Roda]

Originally Posted by bmoore2156

Jon,
How long do you save the test samples for each set of rotors?
Are you required to save them by law?
Brad

We save the samples indefinitetly.
I'm not sure if we're "required", but it is evidence. For the same reason we keep a record of every step in building them.