Home made rotor blades

[Rotor Rooter]

Mountain climbing involves so many risks that only a handful consider the shortcomings neglectable and are prepared to take the risk to have the thrill of their life.

Hi Cita,
What you say is so true.
Perhaps question is one of how far do you improve vehicle safety before the excitement leaves and the utilitarian takes over.

A similar debate about safety was continually active on the previous gyrocopter forum. One side advocated better machines while the other side advocated better pilots.

As for the "shortcomings" of the Schoeffman vehicle, as I see it there are a few, namely:

tyc;
As noted by Cita, "shortcomings" is a relative term, However, you and probably everyone else, would appreciate an upgrade to his remarkable little craft; so that it's range of travel and of excitement can be expanded.

Your concerns and potential solutions are valid ones and worth of individual discussion. However, I would like to, and am, taking a different approach in attempting to solve most of your concerns.

The primary concern maybe that of loosing power. In reality, this concern is actually one of having a safe landing under all situations. IMHO, the objective is to have thrust just before and during the landing. The question then become; What can be done to assure that this 'power' is there without adding to the weight, complexity and price of the craft?


Perhaps what is needed is a Wikinomics style of thread or forum?
"According to Tapscott, Wikinomics is based on four ideas: Openness, Peering, Sharing, and Acting Globally"

Dave

 

[Sita]

Hello Dave,

take a look at the posts in "another attempt back-pack helicopter" and notice that most concerns regarding safety is about loosing power.
So I guess you're on the right track with your idea of the "ultimate" power pack that will enable you to have power for landing,no matter what.
Most "safety concerns" would be minimized with the knowledge that power is "allways" available.

Cita

 

[tyc]

... how far do you improve vehicle safety before the excitement leaves and the utilitarian takes over.

... "shortcomings" is a relative term,

The primary concern ... having a safe landing under all situations. ... what can be done to assure that this 'power' is there without adding to the weight, complexity and price of the craft?

On this end I'm more for the utility postential of the Schoeffmann machine and and ones like it and yes, I agree, "shortcomings" is a relative term.

As for "The primary concern ..." there's no doubt about there's going to be trade-offs, lots of them. Perhaps longer blade root and/or long blades are among these. That will add weight. Then there's the question of "power" being available for an emergency landing and irrespective of the physics drawn on (rockets, chemicals, springs, parachutes, etc) that to will add weight, which takes one right back to root length and/or blade length, also affecting blade rotational speed; designing such instruments is like working with a bowl of jelly, push on one side and it'll bulge somewhere on another side. It will come down to trade-offs and the end result may still look something like what Schoeffmann is zipping around in at present, perhaps just a slightly larger version and still very functional.

Just my two cents.

tyc

 

[Sita]

It just needs to be taken from the "off the shelf available parts stage" to the "designed for it stage".
This would almost certain mean a bigger rotor diameter,different blades,different engine(s),other materials etc...

Schoeffman could take his copter apart in a matter of minutes,ready to be stowed in his minivan,a feature which is worth something I guess.
No need for a helping hand or special tools !!

His little helicopter is the work of one man,it would be unthinkable that a group of engineers/enthousiasts/experimenters would not be able to improve this concept in every way (safety-mechanically-weight (?),etc...) and still keep the "spirit" of the design.

Cita

 

[tyc]

... the "off the shelf available parts stage" to the "designed for it stage". This would almost certain mean a bigger rotor diameter, different blades, different engine(s),other materials etc...
Schoeffman could take his copter apart in a matter of minutes, ... stowed in his minivan, a feature which is worth something I guess. No need for a helping hand or special tools !!
His little helicopter is the work of one man, it would be unthinkable that a group of engineers/enthousiasts/experimenters would not be able to improve this concept in every way (safety-mechanically-weight (?),etc...) and still keep the "spirit" of the design.

From what I know of these things, I agree; different and/or larger blades but still possibly "stock" from what's currently available these days. Different engine(s)? Yes, very probably and larger to.

From this end, the ability to take the little helicopter apart in a matter of minutes and stow it inside a minivan as opposed to pulling it up and securing it to a small flatbed or enclosed trailer, for me that doesn't mean all that much; I'd readily opt for the later. And yes, I agree, there is something to be said about not needing a "helping hand or special tools!" to get this done.

As for the "spirit" of the design I agree. As far as I'm concerned it's nice to be here and see such inovations come about, knowing I may very well be able to take advanage of it or something like it if Schoeffmann or that fellow "jens" decide to market their products. Very interesting people those two.

Just my two cents.

tyc

 

[Rotor Rooter]

Thinking outside the box.

Thinking outside the box.

tyc,

A belated reply to you post #63.

Redundancy need not come with a heavy penalty.


Power-train;
Plus, limiting this post to the use of gasoline as the stored energy. As with most aircraft the fuel can be stored in more than one container. Since the containers are now half the original size the weigh increase should be minimal.

For converting the fuel to mechanical energy, which will turn the counter-rotating coaxial rotors, this 'theoretical' and simple idea may have merit. All it needs is a person with access to some machining equipment, plus an interest in experimentation. Some perceived advantages are noted on the page. It might also be noted that this idea is probably only appropriate for the coaxial configuration.


Rotors:
The use of small blades (propellers) should be acceptable, although the efficiency will be reduced. The disk loading will not be excessively high because the GW of the craft is so low. What is essential is that the blades can provide thrust during normal flight AND be able to restore thrust during a landing from an unpowered descent. This may require automatic pitch change, such as a torque-pitch coupling.

Another unorthodox consideration is; why is autorotation essential???? Assume that the motionless blades provide enough drag to keep the craft upright and they are strong enough to not fold up (propellers are strong enough). It should be possible to provide the blades with sufficient negative pitch that they can be recovered from a high speed vertical descent.

An old thread on the above subject and Absolutely Rigid Rotors is on PPRuNe. I think the thread was back before Sikorsky's reintroduction of the Advancing Blade Concept (ABC).


One might wish to contemplate the fact that Schoeffman's very simple idea is essentially the ABC.
As the craft moves forward, the advancing blades start providing more and more of the lift.


Dave

 

[Jens]

More tests?

More tests?

Hi Nick,

I saw your test on YouTube about 2 month ago - have you done tests with both rotors now?
I am very courios to here what you think about your blades, the rotor and your hole machine.

 

[thumper549]

epoxy will bond to the wood, the polyester, and styrines will let go