Weird thought #1 - rotary engines

[serverlan]

Is their any particular reason people don't run mazda rotary engines?
I thought they would have one of the best power - to - weights around.
( I don't have any figures yet - maybe next week)

I realise that they rev pretty high, so a redrive would be necessary.

Don

[rotor]

Hi servalan ...

Aerosport International in NZ run a Mazda 13B rotary engine modified for aeronautical purposes called WADEAero. They have a Prop Speed reduction Unit design to achieve by gear drive a reduction of 2.2:1 allowing a 72" 3blade prop to transmit the available engine HP without the
propeller going sonic. Engine achieves 175 brake horse power @ 5800rpm Fuel burn (gph)0.5lb/hp/ph(quote of site )

The gyro is one of those in the news section on the main page and has a link to their site in "read more"


~ rotor ~

[le-wardy]

If you go to the Kahu website and download a couple of their movies of the Kahu in flight. You will hear that the aircraft is bloody LOUD with its
exhaust note from the rotary engine. Not good !! Rotarys are well known because of this. Check out the next rotary rev-head you see on the road, and no doubt you will hear the shrieking high-pitch exhaust note. Sounds like a drill going through your head !!

For gyros to be more accepted by Jill and Joe Public flying around above them, a well muffled exhaust will go far to making this happen. Flying neighbourly is something that has to be communicated and remembered all the time. Even the helicopter industry had to do this a few years ago, due to increased noise complaints from people on the ground, which in turn restricted their flight paths and in-flight operations.

The last thing we gyro pilots need is the local aviation noise complaint hotline running hot, from someone buzzing the skies sounding like a large swarm of angry bees above people homes.

[rotor]

Point well taken, and I'm inclined to agree.

People being people will complain at the slightest annoyance (not saying that a rotary compares with slight here either). Rotorcraft in our area are still restricted from flying over built up areas after dark for this reason. And its not like a Hughes 500 NOTAR makes a lot of noise. Even now the poor old Helli pilot gets abused by irate neighbours over the airfield fence at 0300 hrs when he's off to do a job, and thats the truth.

Public acceptance is very important if we wish to continue flying with the freedom we enjoy today. Bad publicity for any reason should be avoided at all costs.

[bones]

That could be a good point for people who fly in that situation where other can get p*ssed about it, but for those of us who fly in a situation where the more noise the better, for moving cattle, rotor noise is best but any thing is better than nothing, most i have seen and talked to, it is straight out of the head with no exhaust at all, the question that i'm still interested in is are they compatable for this job, what did they have to convert to suit, are they as reliable as any other type of engine that is being used. because they caught my eye for the amazing horsepower to weight that they can generate, not sure about the torque yet, havent looked into them that much yet.. :wink:

[le-wardy]

bones,
There's a bloke named 'birdy' who's out at Alice Springs. He uses his gyro for cattle mustering. He finds his machine is more than adequate for the job. Will try to find his email address, to post it here for you so you can ask the man himself with your questions.


Bones,
Here's a link to contact 'birdy',http://www.asra.org.au/forum/pop_profile.asp?mode=display&id=235

[bones]

Le,
Thanks but i'm more than familiar with david, have spoken with him on the phone as well as on the ASRA site, he has a four stoke rotax on his and swears by it has done approx 1500 hrs and nothing more than changed the plugs and oil, now that in any ones language is a good run, but i'm not at the moment in the position to be able to afford the $20 000 odd to put one on.
I'm thinking if these rotary engines can stand up to the pressures of the work load, especially need the reliablity in this line of flying, because most of the time were over some big timber and it hurts when the engine calls a smoko break :lol:

[rotor]

Have a look at the performance figures on the rotaries at this site.
They're not in aircraft but it should give you an indication of what can be got out of these little beasts. A lot of the Mazda 13B's are twin turbo's by the look .. and the later model 13B can get up to 255/6500 BHP/rpm and 217/5000 Torque(lb-ft/rpm) - that's a little more than the average ..and a little bit more than what you need me thinks ... Not being a mechanical genius I'm not sure how this would all correlate after a reduction box was thrown into the equation either ..

Mazda Rotaries have been applied to RV 4, 6, 6A Long-Ez aircraft - theres a little bit in there about them also ..

Have a look under "Reference" or "Engine lists" on the right hand menu -
http://www.monito.com/wankel/wankel.html

[bones]

Rotor,
Me also thinks that is too much hp, but if there is an engine that can give say 150 hp and it's only working at 3/4 capacity i would have to think that the engine would last longer and be happier than an engine that CAN give 150 hp full capacity working it's butt off all the time, and in saying that the full hp isnt needed all time, but like i said before it reliabity that is what everyone should be looking for..
If these engines can develope that sort of hp if needed to get you out of trouble, which is the case as in some helicopters, then that in it's self is safety

[rotor]

bones,

i'm a little ignorant on the mustering side of gyro's. Obviously the flyings down low - how low ??. I did my training at about 200 feet (still training), cows wouldn't even notice you up there, I suppose you have to climb to go over fences :yikes:

Even though reliability is what we're all looking for, it is more so a major factor when your working so close to the ground, so little time to react - and we all know "Murphie Law" ... Yes reliability certainly does spell safety, and I can see where for you lots of horses can get you out of trouble.

How about a shot or two of your gyro. One or two of it out chasing cows'd be great ??

[llewella]

We are slowly [very slowly] working on a Mazda 12A turbo rotary powered gyro. We had a bit of a setback when it unexpectedly cat pulted me through a 5 strand barbed wire fence. I think it is wise to follow car racing practice of requiring two throttle return springs! We had none as aircraft practice is to have none, allowing you to limp home on partial throttle if it disconnects. The turbo is a wonderfull exhaust silencer, compared to a muffler system it is also lightweight.Due to their low parts count they are also reputed to be very reliable. Even if in fairly sad condition they will apparetly keep running while you supply them with fuel and sparks, however a sick engine may eventually refuse to start.
While they are not a light weight engine, their power to weight ratio is quite good, they are also reputed to be fairly thirsty, but this can be addressed by leaning them off in cruise- they don't have any valves to burn out.A fellow called Tracy Crook in the US has one in an RV, he runs a website and can supply components for aircraft use.

John Evans

[rotor]

Hi John, welcome to the site. I think I might have met you at Sth Grafton in 2001 - the day the old lean-too was being pulled down ??
Firstly, sorry to hear about you unfortunate accident with the new gyro. These are the accidents that make us think a little about our own machines and how they're set up. I know mine has a return spring on the carby - I dont have push/pull set up and your point about the throttle staying open after breaking the cable makes some sense I guess.

You new bird sounds like a good project to keep an eye on. What sort of HP/torque/rpm do you think you'll be getting out of the 12A ?? Not to familiar with the rotary engines but envisage that it's either an earlier model or smaller model of the 13A mentioned above.

I'm going to bore people with this, but do you have any pics? I can set up an album in the Gallery for you to upload to if you like. I'm sure there'd be a few interested in seeing your machine/motor and watch it's development.

[bones]

Hey sorry rotor i've been away and i'll try to get some pics for you next time i'm out , i'm grounded at the moment engine gave way on me yesterday, once again reliablity :rolleyes:

Going to get serious about a good engine shortly :lol:

[llewella]

No pictures available at this stage

Geoff.
The 12A Turbo is good for 160 HP. Ours was driving a 72" 4 blade Warp Drive prop, through a Ross gearbox.
I was suprised by the accellaration! It's certainly an engine worth considering.

[rotor]

bones,

sorry to hear about your engine probs, if you were working I hope you put it down ok ?? No probs about the pics - when ever you get the chance.

John,

160 horses ... holy heck !! Bones 'll interested in that I'm sure. It's a heck of a lot more than the measly 72 horses that I've got in my machine .... I'm envious. How do they go economy wise and how reliable are they ???

[rotor]

bones,

sorry to hear about your engine probs, if you were working I hope you put it down ok ?? No probs about the pics - when ever you get the chance.

John,

160 horses ... holy heck !! Bones 'll interested in that I'm sure. It's a heck of a lot more than the measly 72 horses that I've got in my machine .... I'm envious. How do they go economy wise and how reliable are they ???

[llewella]

G'Day

Geoff,
I don't claim to be an expert on rotaries, but I can direct you to a site where there is a lot of expert information, it's www.rotaryeng@earthlink.net.
My understanding is that with the low parts count and simplicity the reliability is very high. Economy is another question, power output of that order is bound to use signifigant amounts of fuel. So if you accept V8 type power you will have to accept comparable fuel consumption. This is where the work of people like Tracey Crook is interesting, he shows that in cruise they can be run quite lean without resulting reliability problems.
These are not a light engine, but their power to weight ratio is quite good if you need that power.

John Evans

[rotor]

G'Day Geoff,
I don't claim to be an expert on rotaries, but I can direct

you to a site where there is a lot of expert information, it's www.rotaryeng@earthlink.net.
My

understanding is that with the low parts count and simplicity the reliability is very

high.

Hi John,

The address to that site looks a little funny, kind of like an email and site address all rolled into one :) Couldn't find it even with a search. Those motors are certainly worth a look at and maybe a play around with, especially for those with the heavier twins. How long before you get your machine in the air do you think ??

[llewella]

Sorry John made a mistake with that link. It is


http://www.home.earthlink.net/~rotaryeng/ACRE.html I cut and pasted it for him so should be

correct.
Hope that is more helpful than the last one.
Llewella

[rotor]

Thanks Llewella,

yes that worked. The site has a fair bit of info. Once again thanks


Geoff

[bones]

Rotor,
First thing to remember in a situation of a motor out is to keep your mind on the job at hand, and yes i got it down with out any damage, lucky
considering where it happened about 200' and over timber got it down through a gap of about 30' in the trees not bad when you consider i have 25' rotors, the chopper pilot who was doing a double with me that day said i dont know how the hell you get that down there with out hitting any thing. After having sending the crank away to get fixed after the bearings failing which was or wasn't the reason for the motor out, it wasn't pressed back together straight because it was overhaulled 12 hours before, should be back in the air this week.
Just like to say that this happened to me after just 2 hours of proper flying but a total of 8 hours including 6 hours of hops ect, since i brought this machine, and that i hadnt flown for about 10 years before this. Rotor most of the time while mustering about 200'- 300' is a good height for getting a good look around but you do need to get down and dirty if they dont want to play the game properly, i try to stay about 50'-100' above the tree line if possible for the sake of powerlines and if the motor gives it gives a bit of time to do something.

[rotor]

bones,

good to hear that you put it down ok. Bad luck about the motor only having just bought the machine. Ten years in the wilderness, your as bad as me having started training in 2001 and only just now started doing hops :) In all i've only done about 3 weeks over 3 years but hope to get right back into it when I get back home in about 4 weeks.

Engine outs are one of those things that should be practiced constantly. They're something you can do every day you fly - steep approach at idle. I found that I liked steep approaches during my twin training and didn't have any trouble with the engine out approaches. Different thing when your mind is chasing cattle though I guess.

[bones]

Hi John,

Was just wondering if i could get abit of info about your rotary engine as i'm having abit of trouble trying to get straight answers, different people equals different answers, what is the total weight of the engine, which redrive are you using and the rough weight of that, have you been able to get it back in the air again yet. Have just been reading a fair bit about them they seem to be getting a good run out of these rotary engines in fw could only find a couple of people who had them in gyros but there was not much other info about them

[rotor]

Bones,

hows the motor going. Any further thoughts on what your going to do??

Just a thought. That twin gyro that Murray and Brian put together has got an ej22 in it and has more than enough power. Talking to Brian and Murray at Caboolture and I'm pretty sure one of them mentioned they were going to put an ej22 in a single seater. For the 6 - 7 grand all up it'd be a good alternative maybe, plenty of power (130 horses) to weight me thinks - and a hell of a lot cheaper than a rotory. Your box off the rotax might even fit.

[bones]

Rotor,
The motor is back in and going like a power house now since the repair job, so far so good, and regards to the upgrade motors i'm thinking that i'll just stick with a ea 81 old reliable motor, but i think i'll leave this two stroke on this one and build something especially for the job :lol:

[hoody]

hey bones, im gonna get serious about this gyro building idea.

ill check out that ea81 in town when i get the chance, but first ill do an order up of aluminium soon if you want some, give us a bell.

those parsons 2 seat and KB2 plans are here too if youd like a look.