Designing a gyroplane for a college design course...need input

KCRSXTypeS

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Ok ladies and gentlemen, here is the deal. My name is Devon, I am a 5th year senior at the University of Kansas. For my senior design class we are to design an aircraft for an AIAA competition which would qualify as an LSA and meet the specs. Seeing as how I am :der: I decided to go with a gyroplane just to stand out from among my peers who are doing typical puller style airplanes. The problem is I have almost no aerodynamic, structure, analysis, or design experience when it comes to rotor craft and the knowledge base around the school is limited. I am using Frankenstein techniques to design this aircraft based around airplane design and am running into trouble. What I am looking for is all the help I can get basically.

What I would like is, since I didn't see a sticky at the top here, all the things to REALLY consider when designing a gyroplane. What are the fundamentals to watch out for, how do I choose a rotor airfoil, how do I decide where to place the CG, what engine should I use, what kind of prerotator. These are just SOME of the things that I am looking for. If anyone has an article or something that could point me in the right direction that would be a big help as well. As a note, I do not actually have to build this thing, just design it. It has to meet the following specs. Please also let me know if you foresee anything below being a problem to attain.

Seating: Two
Cargo/baggage bay volume: > 12 ft3
Fuel Capacity: >26 US gallons
Useful load (people, cargo, fuel): >550 lbs
Take-off Performance @ Max weight, standard day, sea level conditions:
Ground Roll: < 250’
Take-off over 50’: < 550’
Landing roll: < 300’
Landing over 50’: < 650’

Dash Speed: < 120 knots
Maximum Cruise speed: > 113 knots (at best altitude and continuous cruise power)
Maximum Range at max cruise speed: 400 n.m. (accounting for take-off, climb fuel burn, plus 30 minute additional reserve at most economical cruise power setting).

Airplane shall be rugged for operations out of unimproved landing strips, reliable and easily repaired. The airplane shall be easily parked in a standard 40’ wide ‘T’ hangar.

Pilot visibility shall be very good.

Center of gravity loadability shall be sufficient for flights with:
· Full fuel and one 130 lb pilot, no cargo;
· Full fuel, two 200 lb people, no cargo; and,
· Two 170 lb people, 90 lbs cargo, and at least 20 gallons fuel.

Optional capability to utilize high flotation tires (with decrease in maximum cruise speed permitted) shall be provided for.

Instrumentation will be typical of that allowed for LSA class airplanes (basic VFR). Minimum installation of a single VHF Communication radio, and an installed GPS.

The airplane shall in all matters be compliant with Light Sport Aircraft ASTM standards (ASTM 2245), per FAA rules outlining LSA class aircraft.

Operating costs, specifically fuel costs and maintenance (routine scheduled, non-routine, overhauls, etc.), shall be demonstrated to be typical, or below average, for the LSA class of aircraft.

Airplane acquisition cost shall be commensurate with other LSA class aircraft. Production runs of 100 and 500 units shall be assessed.
 
Hi Devon,

Hmmm ... those specifications sure do sound like a Super Cub or variant.

If you want to use a gyroplane, then consider a Tractor style gyro with at least 180 hp, a minimum 30 foot rotor, using the tried and true 8H12 airfoil, all the while maintaining the maximum 1320 lb gross weight. Still, it would be difficult to obtain the required 113 knots cruise.

There's alot out there on Cierva and his tractor designs on the internet. There's also many good books on rotorcraft flight. Look for "Aerodynamics of the Helicopter" by Gessow & Myers. Another good book I can think of off and is From Autogiro to Gyroplane.

Either way, you have come to the right place.

Good Luck and keep us all updated.

Wayne

Wayne
 
What I would like is, since I didn't see a sticky at the top here, all the things to REALLY consider when designing a gyroplane. What are the fundamentals to watch out for, how do I choose a rotor airfoil, how do I decide where to place the CG, what engine should I use, what kind of prerotator.

Just to get you started:

Try to align propeller thrust near the vertical CG. Plan for a generous horizontal stab on the longest arm you can have.

Try to minimize drag below the vertical CG.

The Rotax 912 ULS is probably the best engine if you need to meet the ASTM standards.

Check out the Boeing VR7 airfoil.

Hopefully Chuck Beaty, Doug Riley, and Udi Zeigerson will chime in.

Search for a paper by Gordon Leishman. Gordon is at UMD. He is very gyro savvy.

Jim
 
Hi Devon,

Hmmm ... those specifications sure do sound like a Super Cub or variant.

If you want to use a gyroplane, then consider a Tractor style gyro with at least 180 hp, a minimum 30 foot rotor, using the tried and true 8H12 airfoil, all the while maintaining the maximum 1320 lb gross weight. Still, it would be difficult to obtain the required 113 knots cruise.

There's alot out there on Cierva and his tractor designs on the internet. There's also many good books on rotorcraft flight. Look for "Aerodynamics of the Helicopter" by Gessow & Myers. Another good book I can think of off and is From Autogiro to Gyroplane.

Either way, you have come to the right place.

Good Luck and keep us all updated.

Wayne

Wayne

Look around on Carter Aviation's web sight, You may get some Ideas
http://www.cartercopters.com/pav_12g.html

Just to get you started:

Try to align propeller thrust near the vertical CG. Plan for a generous horizontal stab on the longest arm you can have.

Try to minimize drag below the vertical CG.

The Rotax 912 ULS is probably the best engine if you need to meet the ASTM standards.

Check out the Boeing VR7 airfoil.

Hopefully Chuck Beaty, Doug Riley, and Udi Zeigerson will chime in.

Search for a paper by Gordon Leishman. Gordon is at UMD. He is very gyro savvy.

Jim

I am confused on why you say to use a tractor style? I would think the aircraft would be working against its own prop wash. Thank you for the recommendation on the rotor size as well. I was in a range of 27-30 ft but was afraid the 30 ft would cause more drag and make it harder to achieve the cruise. I was considering adding small wings off of the body to increase lift at speed and unload the rotor so that I could use a smaller rotor. The problem with this was I was going to attempt to use a pre-rotator to have jump take off ability. The wings would make this inherently difficult by adding significant drag during vertical take off unless the wings were small. Also, how would these wings effect stall? I know that a typical gyroplane really has no stall speed because control can be maintained with zero forward airspeed.

In all of the research I have done I have not come across carter aviation!? That is EXACTLY what I am looking to design, gyroplane with possible wings to unload the rotor at speed for less drag, more lift, higher speed, and further range. As far as airfoil, I had heard a lot about the 8h12 airfoil but I will look into the VR7.

Mayfield, you say the 912S is the best for ASTM? Why? I was looking more at the 914UL just to have more power to achieve the faster cruise and dash speeds while still having a low weight. Low BSFC is also a concern and the 914UL has on the order of .42-.45. Also, it is the industry standard.
I will be CADing up my model today so I will post some pictures soon for critiquing. Thanks for your help so far guys!
 
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Jump takeoff increases the complexity significantly, you'll need some sort of adjustable collective pitch on the rotor - and you can't go there anyways with LSA gyros, straight from the FAR:

"A fixed-pitch, semi-rigid, teetering, two-blade rotor system, if a gyroplane."
 
Devon,

This gyro holds most of the gyrocopter records, and it uses the 914.

http://www.littlewingwonder.com/index.html

The specs of,
Maximum Cruise speed: > 113 knots
Maximum Range at max cruise speed: 400 n.m
are probably going to be your hardest design challenge, because gyrocopters fly at far less efficiency compared to an airplane or helicopter.
 

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Hello again Devon,

Before I make any assumptions for this class, are you going to physically build a full size aircraft, a flying model, or a just computer model?

If a computer model, then you can really play with ideas. It's like you have an unlimited budget. You could hypothetically design a tractor with a small turboprop engine producing better than 180 shp at the prop and still weigh below 1320 lb.

By the way, I'm just throwing out ideas. There are more qualified individuals on this forum than I that have better ideas and way more experience. The more ideas and directions you have, the more you can eliminate and come up with a fine aircraft design for your class.

The Little Wing Autogyro is a perfect example of a tractor style I mentioned previously.

Wayne
 
Get Realistic.

Get Realistic.

Devon,

In the real world no one else has been able to design a Gyro that meets all of your specs If those specs are just goals that you would like to hit and you are willing to give and take in order to get realistic then you may have a chance to succeed. Gyroplanes are not very efficient travelers. Most cruise at 65 to 70 mph. If you had enough power (lots) and if you had a fully enclosed and streamline body you could theoretically get up to the kind of cruise speeds you are wanting, but it won't be easy. Doing that and getting the kind of payload you are looking for probably isn't realistic. If you are just dreaming then what the heck, go for it. But if you are expecting to build something that would really fly, you probably need to re-evaluate your goals and learn a lot more about Gyroplanes before you set out to change the world and do more than anyone else has ever been able to do. Many of the people designing the Gyroplanes we have today have spent their whole life with Gyros and have worked very hard to get them to the point we are at today. Best of luck with your project.

Gyro Doug
 
Maybe these construction airframe-drawings could be of basic help to You. They are from the German MT03.

Good Luck Angelo
 

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.... and here the airframe of the Magni series. You find them also on Greg´s page www.magnigyro.com .......

Angelo
 

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I really appreciate your guys help!

This is a theoretical design just on the computer but I do have to use sizing equations to prove my design. Here is a picture of what I spent the last few days building on CAD. I was going to use a 914 for my engine but I found this Wilksch engine which is a 4 cylinder turbo diesel making 160 hp with a cruise BSFC of .43 lb/hp-hr.

foofighterisometric.jpg


For now I am using a Clark Y airfoil for my prop blade an rotor (that may change) and a Liebeck for my wing.
 
Do you have enough vertical surface aft of the CG?

Regards,

Jim
 
To meet the spec. you have been given you will need to think out side the box. The gyro you have sown us isn’t any thing that hasn’t been done before. And it will likely not meet your specs.

Here is an idea that I would like to see more thought put in to.

http://aviationtrivia.info/Focke-Wulf-FW-61.php

http://en.wikipedia.org/wiki/Focke-Wulf_Fw_61

With two rotors you will have a much better aspect ratio and wont need the power of a normal gyro
There are some draw Backs. That may defeat everything you gain but it is thinking out of the box.
 
That is a very pretty gyro, why not more around?
 
The parent company who built the Wind Ryders main focus was on building composite Rotor baldes and they did sell many of them in there day. the gyro's were more of a side note and I do not believe there were very many of them ever built. There are only two left that I know of, one in Denver, one in Washington state. Too bad, they are sweet gyro's that are all composite construction, No subframe at all, and you can fly them in cold weather.
 

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