Has anyone ever heard of the Rotax "hot rod" 140 hp modification?

[eightyknots]

I was looking at a youtube clip that Hongie posted on the "what are your favourite youtube clips" thread. The highlander was a very impressive performer. I read the comments and, after someone asked the Highlander owner what made his engine so powerful, he wrote this comment:

 

"It's a 912S (100hp) with the compression lowered to 9-1 and then turboed exactly like the 914. It's about 150cc bigger than a regular 914 and it makes something around 140 hp. A 914 makes 115 hp."

 

I know that the Rotax 914 is really a turbo-charged 80 hp motor. However it had never occurred to me that the 100 hp (912S) motor could have the same turbo gear fitted to this to increase the performance to 140 hp ...once the compression has been lowered somewhat. This probably means that you don't need premium unleaded to run either.

 

Does anyone know others that have done this (possibly in Australia). I for one would like to know the expected engine life of this arrangement.

 

 

[facthunter]

Probably somewhere between reasonable and GRIM. Nev

 

 

[eightyknots]

The 140 hp mentioned makes sense. The capacity increase is a 25% increase (25% of 80 hp = 20 hp). A 25% increase in the Rotax 914's 115 horsepower is 143.75 hp.

 

 

[eightyknots]

I wonder why this hasn't been tried before?? [someone will probably post in this thread and say " the US military uses that set-up in their drones over Pakistan ]

 

 

[facthunter]

Yes but aeroengines are not buzz bomb engines. They have to keep going. The other Rotax turbo ia 115 Hp and has time limits on its operation at higher power settings, and a reduced TBO..The engine has to rid itself of heat, with the extra power. It also has a built -up crank which has it's limitations.

 

I once owned an unusual Piper Commanche Twin which had a version of the IO 360 ( factory fitted turbocharged) engines. These were not supposed to increase the max sea level power but to maintain climb/ cruise to higher altitudes ,( 15,000 ft plus.)

 

The engine was much the same to look at as the conventional 160 hp Lycoming, but open it up and everything was stronger and it had piston oil squirters to cool the underside of the pistons. The pistons, heads and cylinders were thicker, stronger crankcases, longer reach plugs ,bigger oil pumps etc

 

Lycoming wouldn't have gone to all that trouble unless it was needed, and this was not an increase in power, although it would have no doubt been capable of it and would have done it in an emergency.. Nev

 

 

[eightyknots]

I suppose the pilot in question seems to use this arrangement at low altitudes so he doesn't have far to fall when the engine stops:

 

 

 

[damkia]

Yes but aeroengines are not buzz bomb engines. They have to keep going. The other Rotax turbo ia 115 Hp and has time limits on its operation at higher power settings, and a reduced TBO..The engine has to rid itself of heat, with the extra power. It also has a built -up crank which has it's limitations.I once owned an unusual Piper Commanche Twin which had a version of the IO 360 ( factory fitted turbocharged) engines. These were not supposed to increase the max sea level power but to maintain climb/ cruise to higher altitudes ,( 15,000 ft plus.)

The engine was much the same to look at as the conventional 160 hp Lycoming, but open it up and everything was stronger and it had piston oil squirtere to cool the underside of the pistons. The pistons, heads and cylinders were thicker, stronger crankcases, longer reach plugs ,bigger oil pumps etc

 

Lycoming wouldn't have gone to all that trouble unless it was needed, and this was not an increase in power, although it would have no doubt been capable of it and would have done it in an emergency.. Nev

Turbo-normocharged I believe is the term. It does not increase the effective compression ratio (or power) at ground level but carries a "ground level equivalent" manifold absolute pressure up high so there is the same effective power output without the altitude derating you normally get.

 

The less dense air at altitude is also not capable of air cooling as well, resulting in the metal components needing to dissipate more heat away from the cylinders, and per a normal turbocharged engine including the extra heat generated by the turbocharger in the fuel/air mix (no intercooler) into the overall heat generated, hence the build by Lycoming of everything being a bit heavier and the time derating of TBO.

 

 

[facthunter]

It wasn't reduced TBO as you normally didn't use it unless you went to those levels. There might have ben some record ot high altitude time,( similar to time doing aero's) for an hourly adjustment but I never saw it. I actually had the turbo's removed. It's VH LLV. Should still be around somewhere .It flew the Pacific to get here.

 

They are a nice thing. Wish I could afford it. Nev

 

 

[dazza 38]

Turbo-normocharged I believe is the term. It does not increase the effective compression ratio (or power) at ground level but carries a "ground level equivalent" manifold absolute pressure up high so there is the same effective power output without the altitude derating you normally get.The less dense air at altitude is also not capable of air cooling as well, resulting in the metal components needing to dissipate more heat away from the cylinders, and per a normal turbocharged engine including the extra heat generated by the turbocharger in the fuel/air mix (no intercooler) into the overall heat generated, hence the build by Lycoming of everything being a bit heavier and the time derating of TBO.

I know it as Turbo-normalized

 

 

[Hongie]

haha eighty knots... pretty sure i read somewhere that the US of A does use rotax's in some of there uavs! anyways, here is one mob that does 912-914 hot ups and performance mods... pricey though.. $57k for the top of the line 130hp model

 

http://sportair.aero/category/12-epapower/

 

 

[bones]

Well ok i import a brand of aircraft(that im not allowed to mention cause its in breach of rules) that has a 80 hp rotax that has turbo that produces 135hp of course this is for only a couple of minutes, but it is about 110 hp 100%, and the only real difference between it and the 914 is no computer crap, it is absolutely great performance and good fuel econ. i have one machine in Oz that has about 800hr mustering time and still going strong, the simplisity is so well simple it beg to wonder why rotax did the crap they did with the 914.

 

I will have another brand new machine in town this coming week end so they are definately popular.

 

 

[eightyknots]

Well ok i import a brand of aircraft(that im not allowed to mention cause its in breach of rules) that has a 80 hp rotax that has turbo that produces 135hp of course this is for only a couple of minutes, but it is about 110 hp 100%, and the only real difference between it and the 914 is no computer crap, it is absolutely great performance and good fuel econ. i have one machine in Oz that has about 800hr mustering time and still going strong, the simplisity is so well simple it beg to wonder why rotax did the crap they did with the 914.I will have another brand new machine in town this coming week end so they are definately popular.

You got us all wondering now bones. You're keeping us in suspense

 

 

[bones]

Well if you look at the bottom of my post u might get a hint.

 

Hongee there will more than likely one in your backyard very soon

 

 

[turboplanner]

You seem to be disadvantaged bones since there are others on here flagrantly spouting their wares, even doing business free.

 

 

[bones]

haha eighty knots... pretty sure i read somewhere that the US of A does use rotax's in some of there uavs! anyways, here is one mob that does 912-914 hot ups and performance mods... pricey though.. $57k for the top of the line 130hp modelhttp://sportair.aero/category/12-epapower/

Damn ill sell you a motor every day at that price

 

 

[turboplanner]

To get more power out of the same components you need more pressure in the chamber.

 

The byproduct of more pressure is more heat in the upper cylinder

 

The combination of more heat and more pressure means more load on the components, so more wear, shorter life

 

So a turbo engine variant usually has different components from the big ends to the valve train and lubrication system.

 

 

[eightyknots]

I just 'happened' to come across a website from a chappie selling autogyros . One of the options is to fit a modified Rotax which increases the horsepower rating to 122 hp. This is the short description:

 

"The 912 RST model uses a smaller 80 HP Rotax 912 engine (smaller than the 100 HP 912S mentioned above). This engine has been fitted with a Mitsubishi Turbo that gives full time turbo boost. At full power this engine develops 122 Horsepower and is excellent for heavier loads or high altitudes."

 

Here's the link to that interesting website: http://www.zenogyro.com.au/models_specs/

 

 

[turboplanner]

Be buggered!, what a nice website!

 

 

[eightyknots]

Be buggered!, what a nice website!

It's definitely worth a look for someone who is interested in a quality autogyro/gyrocopter/gyroplane or whatever the fad name is for them these days.

 

(they DO have an identity crisis don't they?)

 

 

[bones]

I have heard say that the 122hp thing is only a European thing as they are limited to 122 hp the rest of the world can have the full 135 hp, just a bit more turbo boost, and if you want it can go right out to 180 odd hp, but that is pushing it a bit i think.

 

 

[Hongie]

gee that would be nice... imagne the rate of climb you could get in a savannah with 140hp pulling you along

 

 

[Mick]

gee that would be nice... imagne the rate of climb you could get in a savannah with 140hp pulling you along

Almost be like a Carbon Cub with 180hp - serious fun! But a dam site cheaper.

 

 

[bones]

It's definitely worth a look for someone who is interested in a quality autogyro/gyrocopter/gyroplane or whatever the fad name is for them these days.(they DO have an identity crisis don't they?)

Yes unfortunately they did/sort of still do abit, but with the likes of this style, and the ELA MT03, Magni, that proving beyond doubt that the modern designed gyro is in fact a safe aircraft.

The worst feed back you get is like, my friends uncle knew someone who used to go to this blokes place and he had one of those gyro things, and he got killed in it trying to learn to fly it, no he didnt have any training but those bloody things will kill you, well DUHHHHH..

 

I cant work out why it is the gyro that sufferes these type of fools trying to teach themselves to fly even today, i think it is the fact that the gyro looks so simple in design, they automaticly think it is easy to learn to fly, the fact of the matter is they are easy to fly, but there is a couple of critical stages of rotor management you need to get right.

 

 

[turboplanner]

The reason is they were sold that way back in the 1950's - as a low cost safe aircraft that couldn't stall, and would just float back to earth if the engine quit, and it wouldn't surprise me if the toll was in the hundreds over the years, many of them farmers. There was one parked at the Broken Hill race track for years. It had a volkswagen engine, and was made from plywood and steel tubing, some looking like water pipe. It may have got of the ground at some time, but probably not for long.

 

Memory imprint lasts an amazing time (I once tried to buy a Subaru Brumby and was politely told the model run had ceased 13 years previously)

 

So in marketing the product, you have to overcome the mistakes of your predecessors up front, so the buyer is in no doubt what is safe and what is not, and you'll do well.

 

 

[bones]

Be buggered!, what a nice website!

Thanks, it was a very interesting learning curve, how to build a site, but i got there in the end, now its easy just adding wording and photos.