120hpTurboprop engine

We aim to rate our engines as follows (at sea level, STP):

TA120TP:

Take-off power (5 minutes limit) - 120hp

Maximum Continuous Power (MCP) - 110hp

Optimum Cruise Power (OCP) - 100hp

TA200TP:

T/O Pwr - 200hp

MCP - 190hp

OCP - 180hp

We are going to attempt to have a fairly flat SFC curve for the 80-100hp range for the -120, and 150-180hp for the -200. This will allow the pilot to pull the power back from the OCP figure, but still achieve a similar SFC at the lower power. We can’t guarantee this but we will be striving to achieve it.

Do you have a torque meter? Nev

Nev, our engineers will determine whether a torque measurement/indication will be required. I cannot say at this point. The display that we anticipate will be an N1/N2 (gas generator shaft speed and power turbine speed) expressed in % of maximum, or possibly an N1/Prop speed display.

Being a constant speed prop system, the power turbine will normally be running steadily at its optimum % while the gas generator % will change to reflect power.

So the pilots primary power reference (for Power + Attitude = Performance) will be a % figure.

As an example for those interested I give the following (figures are only an example and are not true figures):

For a TA120TP powered Lightning Bug with the XXX propellor system fitted, a 250ktas cruise at 10,000’ on an ISA day will require the following:

1 degree nose up and 85% N1 indication.

"We intend for the engine to run on the heavy fuels, JetA, diesel etc. so yes, diesel will be a preferred fuel."

"Yes, that is a little more than the equivalent power pistons, but not a lot."

Avgas, as in many developing countries, is unavailable here. According to Angolan Ministry of Petroleum standards pump petrol here is: Índice de octano Research (RON) 93 - ASTM D2699. A comprehensive analysis of fuel samples taken from a representative sample of petrol stations in Angola along with a 'customer' satisfaction survey conducted by the Universidade Jean Piaget de Angola revealed that 58% of motorists reported fuel related engine problems including pinking, plug fouling and valve/piston damage.

To me, this means that even a low compresion 80hp Rotax would die a horrible death here running on local mogas. I suppose it could be made to run if it were rebuilt to a lower compression ratio and less output. Which is just what you need when you are trying to drag your aircraft off a rough bit of ground in the searing heat of an African day and clear those trees at the end.

We can, however, get diesel. They sell diesel everywhere. Run out of diesel miles in the bush and it won't be long before a kid turns up with a plastic one and half litre mineral water bottle filled with the stuff which he'll sell to you.

The point I seem to be taking a long time to make is that it is all very well having the very latest in fuel injected piston aero engine technology that will only sip an egg cup full of super mogas an hour but it is bugger all use to us who can't get the egg cup full of even middling octane fuel in the first place.

I've read all through this thread and visited the Turbine Areonautics site to pick out all the features and benefits of this engine and nowhere have I seen mention of what to me is the most compelling feature of this engine. It isn't something that this engine does almost as good as the traditional engines, or even does as well as or better. This engine does something that no other lightweight 120/200 hp engine can do here, it can run on the same fuel I sling in my pick up and my generator. For those of us who want a bush hopper to get in and out of tight and isolated places, this engine ticks all the boxes. Think how useful such an aircraft would be, especially in the humanitarian/emergency role. It could provide affordable, no, bloody cheap by comparison, access to hitherto unreachable places. A flying doctor service, a medevac service, anti poaching patrols, all the things that would be nice to have if only there was an affordable alternative to the Cessna Caravans or Beechcrafts, the usual fare lining the light aircraft apron of the international airport and which are restricted to at the very least prepared strips. Add to that this engine has 'KISS'. You need that out in the bush. Anything complicated WILL break. You need Keep It Simple Stupid out here and nothing could be simpler than a turbine with single lever control. So who cares if it is 8 US gallons or twenty child's mineral water bottles full of cheap diesel an hour, it's perfect for here.

"Here’s a question for you guys, what airframe would you like to see a 120hp or 200hp turboprop in?"

The Zenith Super-Duty STOL CH 801-SD and (please!) the Searey.

AAK Hornet.. With "ordinary" diesel you can get wax clogging filters at fairly frequent when you fly, just below zero © temps. You can't rope start or prop swing a turbine to start it and you need a C/S prop. If you cover all that you are on the money. Nev

Has anyone heard any updates on these engines? I checked the website and it says the engine has moved into the prototype stage. I would love to here how it is all going and the sort of numbers for fuel burn ect the 200hp engine is doing.

I have worked with a large GT manufacturer in the US. I worked on the instrument and controls. Recycling waste heat is not used on these turbines as efficiencies twice that of general Otto cycle engines are being achieved. Most first stage turbine blades are made by similar processes to spark gap erosion of quite exotic materials. Cooling ducts delivering air from the compressor through the blades delivering across the boundary layer of the blade. Expensive machining. Maybe3d printing methods could be used. From the prices I have seen in my experiences I cannot see how you could get high performance blades so cheap. If you are using recirculation of heat I would think that you may be able to get the price of the GT low but it asks the question of what extra weight? Also what losses in back pressure from the recycling. I do however wish you the best of luck in your endeavours. I will follow your progress and hope to see a world beater. There are other small turbines on the market similar to what you are designing so you must succeed, but how does theirs compare with your design in terms of weight and economy of purchase and fuel efficiency?

It raises the eyebrows slightly that the last post from flyvulcan is dated December 2017, that's quite a long time ago. And also that the website is still saying that the full new website is "coming soon". Yes I know a website doesn't build engines, but it IS the public face of the enterprise. I too hope they can produce something that meets their expectations, and they sell a heap of them, but I suspect it's a hard road they have chosen.

A few have tried to produce small lightweight turbines for the bottom end GA market. Other Than the RC world I don't recall seeing an end product widely used. Manufacturing costs due design and complex gearing and high end materials, CS props needed, high specific fuel consumption especially when used at the levels most GA planes operate. Engine handling is different to Mr Otto's designs and they can be ruined/destroyed easily if not handled correctly especially during the start sequence. I can see a lot of these engines (if ever produced) being fried! The old piston engine design will be with us for a very very very long time yet!?

Most heat issues with turbines are potentially during the start if you "light them up" before the turbine is spinning fast enough molten metal can drip out the back.

. Piston engines that have a TO power time limited is because the engine is acting as a heat sink. That doesn't apply to a turbine as the hot bits get hot really fast. The engine has a limiting TGT or TIT or whatever the maker calls it depending where the "measuring" point is but it does relate to the power turbine wheel limiting safe temp NOT a power setting which is a separate consideration and measured by pressure between a couple of points in the engine.. IF neither the pressure ratio or the turbine wheel temp limits are exceeded most jet engines can run safely on the limit till the fuel is exhausted. Engine life will reduce, but that's a separate matter if you need to clear trees or the top of a mountain . Handling jet engines is much simpler than Pistons. IF you hook them to a prop the prop has to have a lot of pitch control safety features, normally. Nev

A comprehensive response will come tomorrow. I’m somewhat knackered after a very long day of discussing programming of ECUs with my engineers, speaking with component suppliers, liaising with my Marketing Manager about the new website and social media campaign, planning our assembly facility with the relevant staff, responding to a multitude of enquiries that come in amongst many other things. Things are definitely happening and the engine program is progressing, but it is an extremely technical and complicated program we have undertaken, requiring many resources, time being one of them. Anyway, I shall update the thread tomorrow.

Following on from last nights post, I am now posting under a new username that I shall use when posting about the TurbAero engines.

Please let me start by providing some additional background on the project then provide the latest on the project.

I would like to start by saying that the development of a clean sheet design for a cost-effective fuel-efficient small gas turbine engine is a seriously major undertaking. The expertise required to develop the required technology, the timeframe to conclude such a development program and the cost to do so are likely to be a number of the reasons why noone has been successful in doing this in the past, and also, why none of the big players are interested in undertaking such a program for what they probably perceive to be a minimal recreational aircraft market.

We started down this road over 4 years ago now. To be frank, it took us quite a while to pull together the complete technical team with the necessary skills to carry out this program. Since then, we have had a team of engineers that number around 20, spread around the world that have been working on the individual elements of our program. We have specialists in the areas of aerodynamic components (turbines, compressors, guide vane assemblies), combustion and fuel delivery systems, structures, rotordynamics, conventional bearings, foil air bearings, seals, gearboxes, starters, generators, electronic control units, heat exchangers etc. all working on our project. Many of our engineers have worked for the big guys such as Pratt and Whitney, GE, Honeywell, Solar, Allied Signals etc on both small and large gas turbine projects. We have brought together an international team of engineers that really lead the fields in their areas of expertise and many of who, after having worked for the big guys, are very excited and motivated to be working on our program. These engineers have indicated to us that we have achieved in 2 years what the big guys would take 5-10 years to achieve.

The design process itself is extremely iterative. The design of one component affects the design of so many downstream and upstream components. The engine has undergone many iterations to date but with each iteration, the convergence on the optimal design gets closer and the changes needed get smaller and smaller. We are now at the point where instead of iterating to the nth degree, we need to prototype the components/engine, test it and validate the theory.

For commercial reasons, we elected to pursue the development of a 200hp turboprop before the 120hp turboprop and it is this engine that we have focused on for the last 2 years. The detailed design for the most part was completed months ago and we were in a position to prototype components. Unfortunately, prototyping has been affected by the COVID-19 situation due to the temporary closure of many of our (overseas) major component suppliers. That said, we already have some components delivered and prototyping of others is underway, while the prototyping of the remaining components will commence once the effects of the COVID-19 restrictions on our suppliers allows them to get to our components on their priorities list. Testing of some of our components will commence very shortly.

We still have a way to go to bring the product to market. After prototyping, we have the testing phase, both ground and airborne. We will then have the redevelopment work that will arise from the testing phase, and finally, we have to establish the production line for the engines, as well as the after-sales support network. The planning is completed for these activities and we have already commenced executing on elements of that plan. I reiterate that this will take time. Please do not expect it to happen overnight.

For us, the priority is to do this program properly. At the end of the day, we need to be able to deliver a safe and reliable product to the worldwide market that is supported better than any aviation engine on the market and to be able to do this for decades to come. This will take time and we really need to manage the market's expectations in relation to the time that we will need to do this.

In relation to our website and public exposure, we had planned to implement the new website and social media campaign coincidentally with the running of the first engine which had been scheduled for July, but has been pushed back due to the effects of COVID-19. This would have allowed us to publish verified specifications and performance figures for the engine, rather than projected figures. With the delay to running the engine, we will still publish the website this month, but the introduction of the interactive elements such as the dedicated forum for the engine will be delayed until we are close to first engine runs. We shall launch our Facebook page a little later this year, once the component prototyping restarts in earnest. This will allow us to have content to publish, rather than having a stagnant Facebook page. For us, we want to build excitement around the engine because it really will be an exciting product which once proven and demonstrated will appeal to many, even though many may choose or not be able to adopt it. For us, it is all about being able to offer a modern alternative to reciprocating technology.

We hope that as we become more public about our project that we will receive the encouragement of the aviation fraternity. The emails and calls of support that we receive already are very gratifying and we know from our interaction with the recreational aviation fraternity that many are keen to have an affordable turbine option for their aircraft. The weight saving, the smaller size, the increased reliability (to be proven by us), the ability to burn cheaper Jet Fuels with a fuel burn that should be close to that of the equivalent piston engine rather than 2+ times more fuel burn such as that offered by the PBS Velka TP100, are features that are attracting enthusiasts to our engine. Please just give us time to deliver on what is an incredibly technical and demanding program. The wait will be worth it!

For those who have not seen it, here is the latest rendering of our prototype engine. The production engine will likely differ but shouldn't differ by too much.

Diameter is around 17" and length is around 36" (intake to prop flange). The spinner shown has a 12" diameter for reference.

Best wishes TurbAero.

It looks great.

TurbAero thanks for the very comprehensive update. I really hope you can get this done - this is the sort of thing Australia SHOULD be doing. Just imagine a light turboprop twin, with two of these bolted to the wings - fantastic!

Mini PT6? At the end if the day it all boils down to $$$$$?

...A truly impressive achievement, to have put men on the moon despite being handicapped by archaic measurements.

Yeah, including that most confidence-inspiring aeronautical unit of measure, the slug.

Why-O-Why do people persist with the "unmentionable" imperial measurements???????

I wish you every success. Turbines are a great leap in reliability. That's already a well established fact. They are also invariably lighter. Fuel is more assured than avgas and less critical. Take it away, Ace. Efficiency and PRICE and you're home and hosed.. There's no real breakthrough likely with Pistons. in my view. I thought the Werner radial might have gotten somewhere. Nev

Thanks everyone for your comments of support.

To appease the masses, let me assure you all that the design is being done in metric units but I figured the demographic of many readers here i.e. us old buggers, might visualise inches more easily. To ease the stresses of the metric viewers, I can add the following and rest assured, I shall quote metric figures in future:

Length - around 930mm

Width - around 420mm

Dave

Good on you Dave - I take it all back in metric handfuls.

I am one of the old buggers - school was a transitioning nightmare for me, so I basically gave up on the outgoing imperial and concentrated on the metric. Its so easy to visuals the above figures to almost a metre long by almost .5 of a metre wide SIMPLES!.

But to this day I find myself thinking of tyre pressures as psi... maybe this is a sign of oldtimers alzheimers or something.

AND I have to point out that horsepower is one of those old units too. kW is what napoleon wanted us to use I think.

But to this day I find myself thinking of tyre pressures as psi... maybe this is a sign of oldtimers alzheimers or something.

AND I have to point out that horsepower is one of those old units too. kW is what napoleon wanted us to use I think.

I agree - to me PSI and BHP make more sense than KPa and Kw.

But metric in everything else (and I get picky - metres and millimetres exist, centimetres don't...)

The Metric system was designed by Scientists. The other we used to use was designed by traders and chance. Trump says It's un-american to use metric. What other proof do you need that Metric is the go.? (But use AN with planes). Nev

NASA and Spacex now give all the data for launches and returns in Metric speed and distance