120hpTurboprop engine

[Kyle Communications]

How many compressors...only looks like room for maybe 2?

[TurbAero]

How many compressors...only looks like room for maybe 2?

 

Just the one compressor. The pressure ratio needs to be low because of the recuperator.

 

Dave

[Kyle Communications]

I used to bring in Model turbines and also service and had a Schenck balancer for them here. Until they stopped doing model ones of about 20kg thrust and sold their company to a drone maker who produced 100kg thrust engines. They all only had a single stage so always started easily with compressed air first when they came out then we used electric motors and they were gas start but now its all kero start.

 

Single stage isnt as efficient how are you going to get fuel efficency?... Most of the larger turbines really suck the fuel up...20kg thrust engine most used around 1400ml per minute at full power

[Flightrite]

200 gee gee's in an Otto cycle uses around 60-70 ltrs of gas per Hr. Will be interesting to see what 200 gee gee's produced from a turbine uses? Small GA planes mostly operate blw 10K, an environment not ideal for thirsty turbines.

[mkennard]

Would be amazing to start using this in a flight sim to play with.

[TurbAero]

I used to bring in Model turbines and also service and had a Schenck balancer for them here. Until they stopped doing model ones of about 20kg thrust and sold their company to a drone maker who produced 100kg thrust engines. They all only had a single stage so always started easily with compressed air first when they came out then we used electric motors and they were gas start but now its all kero start.

 

Single stage isn't as efficient how are you going to get fuel efficiency?... Most of the larger turbines really suck the fuel up...20kg thrust engine most used around 1400ml per minute at full power

 

Kyle,

 

There are a few ways to improve fuel efficiency for a gas turbine engine:

 

1. Increased pressure ratios

2. Increased temperatures

3. Recuperation

 

1 and 2 generally result in the need for multi-stage compressors and potentially multi-stage turbines (cost and complexity), the need for different and exotic materials (cost!!) plus there are considerable design issues to be overcome by increasing these parameters. The improvement in efficiency offered by these options is not brilliant.

 

3 however allows, and indeed requires a lower pressure ratio that can comfortably be accommodated using a single stage compressor, and even though the technology associated with recuperators (compact heat exchangers) is extremely challenging to get the required efficiency in a small package, the improvement in fuel efficiency offered by a recuperator over an identical non-recuperated engine is up to 30%. Temperatures cam also be maintained at "normal" levels where exotic materials are not required.

 

We have designed our engine to be optimised at 10,000' where the unrecuperated version of our engine would have a specific fuel consumption in the order of 0.65 lbs/hp/hr (with apologies to the metric folks - I just figure more folks think in hp than kW) while our modestly recuperated version will have a SFC of around 0.52 lbs/hp/hr, which is around 20% improvement. To get that improvement through pressure ratio and temperature increases, we would probably struggle technically and the cost and level of difficulty in manufacturing the engine would rise significantly.

 

It is imperative that we contain the cost of the engine to make it competitive in the market. At the moment, our engine will have a higher sticker price than the Lycomings and Continentals and their clones, but maintenance will be less, TBO will be much greater, reliability of the turbine should be better than for the pistons, the cost of overhaul should be less than for the LyContis, fuel burn will be marginally higher in general (although those that can cruise in the FLs will potentially see some savings), but the fuel is a lot cheaper. What is lost in sticker price should be made up for over the life cycle of the engine.

 

Our engines will not suit everyone nor will they be appropriate for all applications. However, for many, they may suit and may have appeal. I know for me it is a no-brainer to put a cost-effective fuel-efficient turbine in my projects.

 

As an exercise, let me run through the benefits to one of my own projects as follows:

 

I have a kit for a White Lightning 4 seat aircraft which is currently under construction. The kit is shown below, along with a photo of a completed and flying WL.

 

 

 

 

The WL was designed around a 210hp Continental IO360. The owner of the WL N805WL shown above advises me that he flight plans at 12,000' / 215ktas / 9.5 gph (36 litres ph). This is consistent with the feedback that I have from other WL owners who cruise in the 215-225 ktas range burning 9.5-12 gph (36-45 litres ph).

 

I own the design data for the WL and from the performance graphs generated by the designer, a 150shp cruise at 10,000' would offer a cruise TAS of 230ktas and for my turbine, 150shp at 10,000' will offer a fuel flow of 11.5usg/43 litres ph. (150hp x 0.52 lbs/hp/hr = 78 lbs/hr of jet fuel). At 10,000' with my turbine, I shall have the ability to crank up the power to a maximum cruise power setting of 190hp and cruise at about 250ktas @ 14.5usg/55 litres ph. if I wanted to get somewhere faster. I could also climb to FL180 on cannular oxygen and cruise faster with a lower fuel burn.

 

The above calculations do not take into consideration that with my turbine, I shall be able to remove the intakes at the front of the cowling, to be replaced by low drag intakes for the turbine and improve aerodynamic efficiency of my aircraft even further. I also have a 150+ lbs weight saving in the turbine engine installation. For my application, using the turbine is a major win for me and over 2000 hours, the turbine should save me money over the Continental. I also have a smooth and reliable powerplant which will make for a more comfortable and safer ride.

 

Once our turbine is in the market, folks will crunch their own numbers. For some, I expect that the business case will show the economic benefits of our turbine for their aircraft. For others, some of the benefits or simply the appeal of the turbine over the piston will make the case for them to choose the turbine. For some, it won't work out or it will simply be outside their budget.

 

For me, it's about at least offering an alternative to the traditional piston engines. I am confident there will be enough demand that we will be able to build a solid and reliable business around the engines.

 

Dave

[TurbAero]

As an addendum, my engineers are exceptionally keen to complete the detailed design of the 120hp turboprop (the preliminary design work has been completed). They are super excited about what they can do with that engine. Of course, the -120 will be more appropriate to the majority of the aircraft operated by participants of this forum although with a price tag likely between the Rotax 914 and Rotax 915, it will be more suitable for those that have a high utilisation rate for their aircraft where the economic benefits will be evident, or for those that want the other turbine benefits and can bear the cost. Unfortunately, it's not possible to make one for the same price as a Jabiru or Hirth or Aerovee etc.

 

Dave

[Flightrite]

I wish you well in your undertakings, won't be easy as I'm sure you know, plenty of 'challenges' for you and the end user, hope you can sell enuf to make it viable?

[Kyle Communications]

If your not using anything too special that will keep the costs down of course...either a cast compressor wheel or maybe machined from 7000 series alu and inconel combustion chamber and sticks. Inconel will hold up for the heat and cycles...Engine RPM with be low compared to our model versions...do you have ceramic bearings at all? we ued to ahve to change ours at around 50hrs but they didnt have a direct oiling system only bleed oil down the shaft tube. The gas side coupling would be interesting to see.

[kasper]

If you can do a

1. single power lever controlled

2. 120hp turbine

3. with a CS prop

4. for less weight and complexity than a 914/915

5. with a SFC of 600g/hp/hr

 

for the same $$ as the 914/915 with CS prop I think you will find a fair few takers in the high end RAAus group and the fast GA experimental ... except RAAus tech will have a fainting spell over them.

 

67'ish L/H of jet A for a 90hp delivered cruise is not unbelievable and would be accepted by those who like the cache of a turbo prop as much as those that like the ability to hold that 90-120hp up to max cruise up as high as we are allowed ... looking forward to seeing them appear.

 

And while not your issue I am still sore about the deposit I lost on the lightening bug kit back in '97 ... RFW were a bunch of scammers ... but I am happy that an alternate engine is available and being put forward for the airframe ... my original still in crate 100hp 2SI sits in the corner of the storeroom just mocking me.

[TurbAero]

Unfortunately at the moment, I cannot go into specific detail around our technology and materials etc because we are in the process of patenting and protecting our IP. I guess what I can say is that we are aiming for a TBO north of 2000 hours for these engines and the technology and materials used in the model aircraft engines does not come close to offering the dependability and robustness required by our engines. For an engine that may operate in snow or desert sand storms and everything in between, we need to utilise durable materials. FYI, an AL compressor wheel does not meet the structural requirements for the compressor for our 200hp engine. The bearings used will reach the TBO, not like the 50 hours on a model aircraft engine. This philosophy and need for dependability and robustness extends to all components of the engine.

 

Dave

[onetrack]

Conversion of an energy source to power in a simple rotary form, in an efficient manner, is a dream that has escaped a multitude of engineers and designers.

But I would be concerned, if I was developing a fossil-fuel-powered, relatively-simple, small rotary-type engine, that electric motors and batteries will soon overtake the likes of turbines for an aircraft power source.

The salient point is that all the current R&D in Universities, Corporations and Companies, is towards electric motive power and battery development. Even the Saudis are despondent over the future of fossil fuels.

[kasper]

Conversion of an energy source to power in a simple rotary form, in an efficient manner, is a dream that has escaped a multitude of engineers and designers.

But I would be concerned, if I was developing a fossil-fuel-powered, relatively-simple, small rotary-type engine, that electric motors and batteries will soon overtake the likes of turbines for an aircraft power source.

The salient point is that all the current R&D in Universities, Corporations and Companies, is towards electric motive power and battery development. Even the Saudis are despondent over the future of fossil fuels.

Yep. but ...

A rotax 447 equivalent (40hp peak 30hp constant) 1 hour flight duration with a 10 min reserve electric set up off the shelf today from an electrric aircraft engine sytem provider kicks in at 96kg installed ... even the R447 with an hours fuel at full throttle is only 65ish kg

You have to incl. full equivalent systems eg fuel tank and systems weights for fair comparison but the electric options are still a long way off even coming close to working for general recreational flyers ... and the cost of the R477 equivalent electric setup is nearly the same as a new R912!

[TurbAero]

If you can do a

1. single power lever controlled

2. 120hp turbine

3. with a CS prop

4. for less weight and complexity than a 914/915

5. with a SFC of 600g/hp/hr

 

for the same $$ as the 914/915 with CS prop I think you will find a fair few takers in the high end RAAus group and the fast GA experimental ... except RAAus tech will have a fainting spell over them.

 

67'ish L/H of jet A for a 90hp delivered cruise is not unbelievable and would be accepted by those who like the cache of a turbo prop as much as those that like the ability to hold that 90-120hp up to max cruise up as high as we are allowed ... looking forward to seeing them appear.

 

And while not your issue I am still sore about the deposit I lost on the lightening bug kit back in '97 ... RFW were a bunch of scammers ... but I am happy that an alternate engine is available and being put forward for the airframe ... my original still in crate 100hp 2SI sits in the corner of the storeroom just mocking me.

 

Kasper, you have my immediate admiration for being a fan of the Bug and it's a pity that you were let down by RFW. I've got 2 x 2si engines that have been taken out of Bugs adorning a hangar floor in the US. When I've finished my resurrection of the Bug (a side project of passion for me), I'll offer you a new kit that will be fully COD so you can't get burned. You could then put a -120 or -200 into it!

 

As for your 5 criteria above, our aim for the -120 is to meet all those criteria but with a much better SFC. A target of 300g/hp/hr is pretty close to where we hope to end up with the -120. The recuperator, according to my engineers, will be more influential on the -120 than the -200 due to the smaller mass flow through it.

 

Dave

[SplitS]

A 200hp turbine would be a perfect match in my bus. 2000 hours in a privately owned AC is a lot I average just under 100 hours per year so it would take over 20 years to reach TBO. A new lycoming runs around $45,000 if your engine comes in under 60k I would very interested over that and I will probably pass given the price vs speed improvement. Fuel flow is not such a huge factor as long as it stays under 60 Lphr in the cruise.

All the best with your engine.

[Flightrite]

200 HP whether being produced by an Otto cycle or a squirrel cage with a 1000 large rats in it or a fancy turbine is still 200HP going to the prop.

The trick is how much squirrel food do you need to feed it to get that 200HP??? I used to enjoy the reliability of the turbines I operated but was glad I wasn't paying for them!?

[onetrack]

We are only one small breakthrough away from electric-powered aircraft making sizeable inroads into fossil-fuel-powered aircraft. That small breakthrough will be lighter batteries with more power output.

Samsung now has solid-state batteries in the offing, which promise lighter weight with more energy output. This is not any theoretical idea, it is reality.

With the amount of effort going into battery research right now, I can see fossil-fuel engine development withering on the vine within a few short years.

 

The stars are aligning to bring electric-powered aircraft to the forefront of design. Those stars are being lit up by the corona virus causing aviation havoc, by a need to reduce operating costs (which specifically includes fuel costs), a need to reduce maintenance costs, and a strong desire to reduce emissions - and that includes aircraft emissions.

Aircraft designers will now go back to their drawing boards (well, computers, actually), and produce new aircraft designs centred specifically around electric motive power. The future is here, and we have a glimpse of it, below.

 

https://www.pv-magazine-australia.com/2020/06/01/magnix-electric-aircraft-engines-take-to-the-skies/

[kasper]

Im happy to be proven a doomsayer on high density electric power storage ... but I've lived through several decades of the ultra capacitor and high density batteries are just around the corner... and power density on off the shelf is around 5.75kg/kwh or 0.175kwh/kg

 

I'll happily go electric when the power density of electric storage is 1.7khw/kg installed weight ie a ten fold reduction in weight ... it will then compete happily with IC engine system in the 50-100hp class for a 3-4 hour flight duration.

[Kenlsa]

Good to see the article in the OZ on the front page of the “Future Adelaide” insert.

Ken

[TurbAero]

Thanks Ken.

 

It’s nice to get some positive press and supportive feedback while we are all working our backsides off to get the product developed, tested and into the market.

 

It is no small feat to get to where we are now.  The challenges in many areas including developing cutting edge technology, finding the right people for our team, funding etc. have all been enormous and I feel extremely proud of what our team has achieved to date.

 

Where we are in our program today after 3 years would have taken Pratt and Whitney 7 or 8 years and $50m.  
 

We have appreciated the support of both the local and federal governments, but more so, the small group of individual shareholders in our company who have confidence in what we are doing and who have been unwavering in their support, particularly through these tough Covid times that have also affected our program significantly.

 

Things are taking longer than we would like but that is the nature of a highly technical, Covid affected development program.  The positive takeaway is that we are making tangible progress and what we will have to offer when all is said and done will be a product that the aviation community will appreciate, combined with product support that will also be appreciated.

 

Safe flying everyone.

 

Dave