New To Gyros Looking For Gen Info

gyrodrmr

Newbie
Joined
Aug 24, 2008
Messages
3
Location
berea,ky
Hello all,
I have been interested in gyros for quite sometime. I am now looking at building and/or purchasing one. I have looked at several aircraft engines that have been very expensive. I have recently replaced the engine in my chevy lumina. This was a v6, 4 stroke obviously, with approximately 170hp, installed for $3100. What makes a 2 stroke engine (much fewer moving parts) for gyros worth $6,000 to $10,000 depending on the manufacturer? I have seen certain people use Subaru's and Volkswagon's, has anyone used reliable engines like Nissan or Honda? As you can tell I am trying to get in the air as cheap as possible however I want to be very safe as well. I just cant swallow the price tag for engines. Any info would be greatly appreciated

Gyrodrmr
 

Racer

Senior Member
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Oct 9, 2006
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1,594
Location
Colorado Springs, Colorado USA
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Air Command CLT N7512X
Welcome Greg,

These two strokes you see are not your common two strokes, Most of them are engineered for better reliability, have stronger bottom ends and have redundancy built into them as well like duel ignition systems, etc.
Most of the engines designed for light duty aircraft have a very good power to weight ratio and it really does come down to you get what you pay for.

Yes you are correct, There have been many auto engine conversions over the years, some work out better than others. Some that have been used are Volkswagen, Corvair, Subaru, Geo/Suzuki, Mazda rotary, Honda and a few Diesel engines as well. Other engines used were off of motorcycles like BMW and even a few Harley engines and I am sure I am forgetting more than a few. I myself converted a 4 stroke engine I took out of a Snowmobile and have had good results so far, here is the thread if you would like all the details. http://www.rotaryforum.com/forum/showthread.php?t=16100&highlight=Yamaha
If you do decide to use one of these engines you must be aware that you may not have anywhere close to the reliability or longevity as a more expensive engine purpose designed for aircraft.
Other issues arise as well such as wiring, prop reduction, mounting challenges both for strength and rigidity as well as weight and balance so as you can see, even though it may seem like a good idea at first there is a whole lot more to the initial idea of "Hey, I will just use one of these cheaper motors."
Most of the time by the time you are done you will have spent at least as much if not more than if you just bought a purpose built motor in the first place.

Because of your low altitude I would suggest you buy a used proven machine to start out with, there are some really good deals that come around from time to time.
Have someone who you trust check it out for you before you buy it to make sure you are buying a safe machine. Ask many questions here on the forum, people will bend over back wards to help you in any way they can. Set aside some of your funds for training in a two place with one of the available instructors and I believe this is a plan for many many years of very rewarding flights.

Flying a gyro is one of the most rewarding things you will ever do in your life, do it rite and learn as much as you can and you will start experiencing things and making memories beyond your wildest dreams.

Welcome to the forum, Todd
 

jcarleto

Aluminum Supporter
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Jun 5, 2007
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3,571
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Taylorsville, GA
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Beech Bonanza G-35 N4638D/"The Bulldozer" 2-Place Gyroplane N575EE
Total Flight Time
Several
Gyrodrmr,

It's all about power-to-weight ratio. Weight is critical to most aircraft. Some of the 2-cycle engines have excellent power-to-weight specifications. Rotax, for example, is actually built for aviation use. It reflects a more expensive design than say, a motorboat 2-cycle, because if its intended use. Subaru, Geo and Suzuki automotive engines are popular for their power-to-weight ration. They aren't built for aviation and have to have some modifications.

Most auto engines used for aircraft are selected for their power-to-weight ratio, combined with the ease of conversion to aircraft use. Once a track record is established, that also weighs heavily in the popularity. Any time you venture into new and different, you become a trend-setter. You could end up with a great new idea for aviation use of an auto engine, or you could end up at altitude with an oil pump that couldn't take a continuous 4000 rpm operating range.

There are also considerations for aircraft engines you don't have to bother with in a car. Finding out what items or parts need to be removed or tied down so that if/when they break due to vibration or airflow, they don't visit the prop on the way down, for example. Sometimes cooling and exhaust systems can be a challenge.

That said....people like to experiment. I've flown Fixed-Wing aircraft with Corvair and VW engines. I am building a gyro with a Subaru engine. All of these have a fair track record. You can get reduction drives for these from multiple sources. There may be a source for Nissan conversions and reduction drives, but I don't know it, nor do I know of an aircraft personally using one. A couple of things:

Reliability in a car isn't necessarily reliability in an aircraft.
Knowing what to expect in advance from someone else's experimentation is always a good thing.
Getting parts and instructions for what you want to do has value.

These opinions are my own. They were worth at least twice the price paid for them. Others may have differing opinions. I hope they are a bit helpful.

*JC*
 

gyromike

Administrator
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Oct 29, 2003
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Abbeville, Louisiana
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Bensen B8MG
Car engines are cheaper because they build 'em by the millions.
Easier to spread out tooling and manufacturing costs versus a run of maybe thousands, if that much.
 

ultracruiser41

Gold Member
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Nov 2, 2003
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2,566
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NC
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Greg,

Welcome! You'll find alot of answers here on the forum....it's good to visit any flyins you may have in the rea to see and experience gyros.

Our Chapter is having a flyin in Wrens, GA...in October. Go to PRA13.org for more info.

BarryK
 

gyrodrmr

Newbie
Joined
Aug 24, 2008
Messages
3
Location
berea,ky
I appreciate the info gentlemen. I am curious as to what your thoughts are regarding a 2stroke or 4stroke engine. From my early to late teens I ran motocross which at that time was predominately 2strokes. Although they were very dependable mechanicaly it was a constant struggle to keep these engines tuned for top performance. The difference between morning events (cool) and afternoon events (hot) meant a tuning. We would also run the engines lean on oil to acheive that extra umph at the end of day events. Obviously running these engines lean meant a piston and ring change frequently. I also noticed if you ran these engines rich they fouled a lot of plugs. I guess the question I am trying to ask is this, as Racer and Jcarleto noted above these are much more proven engines than what I am familiar with. I would think the fuel ratio would be a little rich due to obvious cost and reliability issues, do you have the fouled plug issue with these engines as well? Also, is it a constant struggle keeping these engines running at peak performance from morning to night and day to day?

Bare with me gentlemen, I greatly appreciate your responses. I will continue my research and I am sure will have many other questions throughout this process. For now I have to go to work unfortunately its not the sky.

Thanks, look forward to reading your responses
 

gyromike

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Bensen B8MG
gyrodrmr,

The Rotax engines used in aircraft descend from snowmobile engines, but they are derated quite a bit. They don't turn as many RPM's or put out as much horsepower. This is done for reliability and longevity. Since we aren't looking to squeeze every bit of power out of them they tend to tolerate the changes in jetting due to temps and atmospheric pressure.

Once they are jetted properly, most owners have no need to rejet.
I know of several Rotax owners with several hundred hours on their engines with nothing done to them except routine preventive maintenance.

The same may be true for other brands, btu Rotax seems to be the most common.
 

jcarleto

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Taylorsville, GA
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Beech Bonanza G-35 N4638D/"The Bulldozer" 2-Place Gyroplane N575EE
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Several
Gyrodrmr,

My experience with 2-cycle is limited to my recent purchase of a gyro with a Rotax 503. The recommendation is to run a 50:1 mix and change (not clean) the plugs every 25 hours. I've changed the plugs twice. They have been clean as a whistle and slightly tan. I believe this is a normal condition. I have run the engine in ambient temperatures ranging from 70 degrees to 101 degrees with widely varying humidity and have not noticed any particular power shift. The temperature and humidity do have significant impact on lift and therefore aircraft performance in general.

*JC*
 

ToolmanTim

Newbie
Joined
Nov 29, 2007
Messages
40
Location
West Palm Beach, Fl
Gyrodrmr:
Welcome to the forum.
Having just gone down this path I would suggest taking some lessons to see if this is for you because if it's not you don't have to worry about engines.
If you decide it is for you then remove "cheap" from your thought process and replace it with words like "robust" and "reliable".
This applies to everything including the airframe.

Heres my take on engines:
If you keep your gyro light you can stick with a 503 or 582 rotax or if you want 4 stroke look at an HKS (I went with an HKS).
If you decide 2 stroke with a Rotax because the care and feeding is widely understood and if you want to upgrade they have resale value.
If you build a gyro put a new engine on it the last thing you want is someone elses problems.
If you can't afford a new engine save until you can.
Unless you are really mechanically inclined I would stay away from auto engine conversions (Maybe on your second gyro build).
Remember engine outs can be a potential disaster so do lots of research and understand the risk/reward ratios of your choice.
Just some of my thoughts.

Tim
 

Resasi

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Gyrs, RAF 2000/Mgni/Bnsn/Hrnet/Mrlin/Crckt/MT-03/Lyzlle AV18-A/Prdtor. Pax ArrowCopter
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100+ gyro, 16,000+ other
Tim good commonsense post for a beginner and I am a beginner. This post has really helped me get a clearer idea of what I want and why I will accept that I will get what I pay for even if it is going to cost me a bit more.

I think I will bite the bullet and go for a new Rotax 503.
 

PPG Doug

Sport Pilot Gyro Guy
Joined
Nov 15, 2005
Messages
394
Location
Xenia, Ohio
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100hp Subaru powered Dominator (SOLD)
Total Flight Time
Few hundred.
Welcome!

Welcome!

Another midwest gyro guy? Great. I'm just up in Dayton, OH.

You have some great Cincinnati area Gyro resources also.

Shoot me an e-mail if you're interested...

Doug
[email protected]
 

animal

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Mar 31, 2004
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Deleon Springs Florida.
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Hillman Hornet N8063D
Doug, did you ever get those carbs worked out yet? I think I am going to try the dual zenith carbs that came on my engine.
we will see how they work out.

I just posted more pics under my falcon build thread.

good luck with your subbie.
 

scottessex

Sling-Wing Pilot
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Nov 12, 2003
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central, ga
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If you are interested in alternative engines...CONTACT magazine is a great resource.
http://www.contactmagazine.com/
But the best thing to do is get a gyro with all the current proven components and learn to fly.
THEN, and only then, after you are comfortable with your flying skills, then you play "test pilot" with different engines. Other wise you are tasked with learning to fly, test pilot, engineering, prototyping, and R&D all at the same time.

I have converted a suzuki 530 snowmobile engine with a rotax gearbox, the engine runs great on a test stand, but my rotax 582 runs so well I cannot bring myself to tear down a perfectly good flying gyro just to try an engine swap, not yet anyhow.
I also have a BMW K100 engine I am converting to aviation use, but in the mean time I get to enjoy flying my proven rotax/dominator setup. You can always buy a new rotax and love and care for it, and KEEP RECORDS if you ever plan to sell it, after you swap engines you will be able to get a decent return on it.

Buying used rotax's.......If you buy a used rotax, make sure you can hear it run...
Even then an overhaul or rebuild will cost $900-$1800.....so if you get a good deal on a used engine, add the $1800 to the price and see if it still adds up to a good deal.
Most people do not keep records on the engines, this severely reduces the value, as the engine history is purely word of mouth speculation.
 
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