GG, the eurotubs are designed around the rotax engines.... the machines are built to that imaginery 450Kg mtow and they often fly well overweight as it is now.... if you add another 100-200# of weight to add a Subaru or lycontinental GA engine, the machine will be that much heavier again, different hang and cheek plates, would need stronger frame to counter the weight and stronger torque pulses etc... it isn't just a case of pull out the rotax and stick in something else..... Now a 618 if they were to make them again, arctic cat, maybe even the flat 4 Hirth? to me, (lighter engine) might be a different story somehow someone needs to make a lighter engine make as much power, even if it is 2 stroke....

One thing I will say (sorry Christine) is that I think rotax would do heaps better to have the turbo set up draw thru and working all of the time, rather than the turbo doing nothing until full throttle, then it pumps .... I prefer a turbo to be compressing a bit even at half throttle.... if nothing else, it compensates for altitude

Need altitude compensation like an Enstrom, A turbo charger to keep sea level performance all the time.

Yeah, from what I understand, a 914 only benefits from the turbo in the last 10% of throttle.... otherwise it is doing nothing except going along for the ride and adding weight? This might not be the case, but my turbos have always been constantly pumping even at half throttle adding a little boost....

If what I heard is true, then a 914 is really just a 912 with panic power at full throttle (limited time use)? May as well just have a 912 and a small nitros bottle?

I may be wrong, if 914 owners can comment that would be good

Ronnie Smith of Mississipi light sport is fitting 912 & 914 's with larger bore cyl/piston & beefed up cranks ... he backs up his work .. which negated the ROTAX WARRANTIES ...... sounds like the guys with the bigger hp mods are enjoying them ... afew issues .. been addressed! ... watching & assessing

I never heard the final report on the MTO 3 crash here in Vic in late 2012 ... involved an experienced instructor RT & passenger ... but that fatal wreck was thought to have an element of "box-canyon ... wind over-the-ridge- failure to get a sufficient climb -to-clear terrain !!!"
A friend who flew that Calidus from Brigham back to spanish fork after ROTR ... said it had lousy performance with the 912 @ that Utah elevation with just ONE... where they were flying in CO was even worse ... two-up ...OUCH!!!!
Suspect more will come out when Michael analyses the event!

The 912 is actually a 100 hp motor, 914 is 80hp without the turbo. Victor with the MTO on floats (Hydrogyronut on the other forum) has just done the rebore and is flying with 134hp - likes it!

Has anyone ever thought of putting a normal draw thru setup on a 100hp motor? or are they not up to the task? (The motor, not the people) I am thinking like a 100Hp and put a carbon seal turbo and an SU carb and just run it with an overpressure wastegate, so it boosts form about 40% throttle and only about 8# boost max?

Is it the crank that is the weak point? Or is it just general, because built so light?

thanks christine for your info, on ronnie smith work, and loftus on the 134hp, i dont have experiance to playing with 912 and 914, to expensive for me, but cool for the one that have the money to play with, desmon build a big bore 120hp with a 4to1 stainless pipe, i think some put 1500cc big bore kit on the market in the past, the 100hp is just a 4,5 milimeters bigger bore. that give 141more cm3, 1352.2 vs 1211.2 for the 80hp and 115hp, and 10.5 comp ratio vs 9to1, what i read with guy like leading edge that report on what they see, and i think rotax make some thing different than other engine maker that i dont like, and i know that rotax is the best flying motor today, is rotax is the only one to put a 2stroke crankshaft in a 4stroke today, the only 2 other manufacturer that i see that make this is 30year ago and more, its in the old suzuki gs 1150 in the 1980decade and yamaha xs650 that is a 1960 design, in the 90 suzuki stop this for is gsxr model, and i never see other yamaha model that have this, and many othe engine i play with, other than harley but its bolted crank pin not just press fit, but its another old story, arctic cat 2cylinder 1050cm3 turbo sled engine put 177hp at around 7800rp, and the yamaha genesis 150hp, dont have 2stroke crankshaft, and can take double is hp some time and more, you cant shift a one piece crank, you have to broke it, but what can happen with a 2stroke type crank and that appen many time is with is many more parts and because of is segmentation to assemble it, that cause week link, many engine builder need to tig weld these parts, even crank rebuild shop offer this service to normal public, not just racer, because we know this is a week link, what guy like leading edge report when they open the 914, to overall rebuild or trouble repair, is if some time the wastegate dont work properly and the engine overboost a little, the engine work with detonation or ping, with time this overload shift the crank out of balance and the engine slowly self destruct,if you put more hp or output on this design it will destruc more rapidly, you have to tig weld the cank pin but.... if you do this no rotax waranty.... a one piece crank can not shift, why every 4stroke today have one piece crank design..., why yamaha, honda, kawasaki, suzuki,all car maker and every all other brand never put press fit 2stroke crank design in 4stroke motor today , i am not an enginer but really think that rotax need to change this to make a more powerfull motor, lycoming dont have press fit crank, ronnie build really good engine with mods i think, people tell he is the best and are happy, but have to offer is own waranty, because rotax dont back you i think, even if you just blueprint your motor for more durability. just some little thing i see with many year of motor play.

Wow, I see the problem Martin.... a 2 stroke segmented crank would suffer badly from the strong torque pulses of a 4 stroke that explains a lot

Evidently Mikes crash happened at night? That would explain why he may not have been able to turn around safely especially if the landing light only faces forward

Harley's use a segmented crank........but that is comparing apples to oranges. They should use a billet crank, and add another $1000 to the cost of the engine. LOL.
The new 2 stroke technology is awesome, in the boat motors, just takes so much to convert them, but that would be nice to have a 200hp v6 2 stroke.

Harleys only have one crank pin between the 2 massive balancers because they have only one conrod (and another articulated conrod both on the same pin)..... one pin is not so much trouble..... it is when you have multiple pins like in a 582 or the 4 stroke rotaxes you run into pin creeping and crooked cranks... the only way to stop it is to weld the pins so they cant creep.... but then, when the bearings need to be replaced, you have to buy a new crank, bearing and rods .... so an expensive new crank and rods, plus the cost of getting them checked straight, then welding.... will only legally last 1200 hours.... then you have to do it again

2 and $ stroke single cylinder dirt bikes only hav one pin and pressed segment, but they never creep, because only one pin

A guy in has a gyro with a V 6 Evinrude.... it is extremely noisy (wrong exhaust) needs tuned chambers, and it drinks about 10 gal per hour It is G150, the red one in the pic


http://www.asra.org.au/smf/index.php/topic,5237.0.html

yes elwood for harley you are correct, the crank pin is not press fit, its taper with a locking keyway to not shift and is bolted and torque to 600ftp, the only big problem i see with 2stroke vs 4 and i know that 2stroke today technology is really good, like cat and etec sled motor and etec evinrude johnson, but you cant beat 4 stroke like yamaha durability with new 2stroke tech, never an etec direct injection 2stroke will outlast or make the same amount of run time hours, but they can push more hp for weight than yam but will not last, and i dont think company like rotax will put new 2stroke tech in flying motor, they can easily but have enuf with is 4stroke, i know that some poeple will try to compare there own etec boat motor.... and tell i made thousand hours and year with my etec evenrude motor and is the best boat motor of my life, and think that the etec 160hp sled motor is the same as boat motor but... no... look at the spec, you know that an engine durability and wear depend of its power output, and to make it more durable you have to ad weight some where with more heavy parts, if you try to push more hp with less weight, you have to deal with less durability and go boum! with 2stroke you can push nearly double the hp for the same cm3 or cubic inche than 4stroke, because you have 1power explosion stroke every 360deg turn of the motor, with 4 stroke is one every 720 or half less to deal with, ok compare the fantastic long lasting etec boat motor, the 25hp is the same size than the 582 rotax 76bore by 64 stroke and etec is bombardier rotax, take the 582 and derate it to 25hp at 5500 will it last a longer time..... the boat 30hp is 863cm3 its more than the 160hp etec sled engine, if you push 30hp with the etec 160hp sled motor do you think it will last 10year..., ok another little spec than i like you to look on the brp, evinrude.com website, if you look at the 25hp they have live video engine test and spec, but .... we always look at bsfc you can check on wikipedia, brake specifique fuel consumption, rated in lbs hp hour, or gram litre hour metric method, ok new tech 2stroke direct injection, look at the 25hp etec spec it burn 2.6 us gallons hours at 5550, double is output he can easily its the same motor as the 582 65hp, it can push 50hp no problem with is new tech and direct fuel injection the last best technology, but you will burn bouble the fuel, or 2.6x2= 5.2 gallon us an hour , i think for 50hp its very near the 30years old 503, in fuel burn, the v6 150 hp boat motor is a 2589cm3 its more than 3 time the etec 160hp sled motor and is the equivalent that the 800cm3 sled motor push more than 480hp, and imagine the bigger 3.441litre v6, the sled motor is 200hp litre and the 300hp etec evinrude to compare with weight hp rario need 688,2 horsepower , where is the new tech play on this, and the last calcul, the 5.2 gph burn of the new motor if you double it at 50hp, is a bsfc of 0,624 or 0,62 5.2usgal at 6 pound = 31,2lbs divided by 50hp output is =0,624, the 25year old tech 582 with carb is 0,65 on rotax website, i think if you look at today 2stroke technological advancement vs 30year 582 its like night and day in term of parts that can fail, and number of componement to make the engine work, and one last thing in term of durabylity of 2 vs 4 stroke, you know the 4stroke have a perfect cylinder bore, nicasil, sleeve, ceramic or wathever finish, with 0 no hole perfect like glass, the 2stroke and the new more powerful even more, nearly dont have cylinder wall, look at this pic and tink that the ring only work and hold on this small bridge between the ports and scuff at every up and down stroke at more than 6000rpm , compare this with a 4stroke that have full ring support 360deg and slip up and down on a perfect finish, i think its really not the same work and wear. excuse my long post but for some that like to reed on this subject, i try to make it short as possible

this gyro can be good to play in the madmax 4 movie muz it can fear people and start them to run like hell to hide with a sound like this the first pic is one of my rotax 670cylinder some new model have many more and bigger ports and less cylinder wall

i know i bust the thread with my motor long bored post but its on wolverines forum i dont know mike personnaly, but i wish you a speedy and perfect recovery mike ,

I do understand there is a LOT of engineering that would need to be done... to adapt a heavier engine behind an Euro-style gyro... Most mods require lots of engineering on aircraft.
Remember Muz... I have an A&P ticket... however I do not practice... and have no plans to practice again. Not interested in the potential liability.