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Turbine Aeronautics

Love turbines but if you have to ask how much or fuel burn gives you pause it is not for you. Also these tiny turbo props and turbo jets often have very low TBO.

If you want a turbo-prop a used TBM 700 or Piper Meridian or Cessna Caravan is the way to go. The older ones are now $750,000 or less used. Heck you can get used Mitsubishi MU-2 or Turbo Commander cheap, but care and feeding of two turboprops is expensive. Hard to beat a PT6 or TPE331.

Turbo Jet? A used Lear 24 or early Cessna Citation can be had for $250,000 or less.
 
The big deal with this design is the recuperator which is extensively used in stationary gas turbine setups. This can have a significant effect in reducing BSFC figures. Big challenge to make work well on an aircraft application but will be worth it if they can.
 
Love turbines but if you have to ask how much or fuel burn gives you pause it is not for you. Also these tiny turbo props and turbo jets often have very low TBO.

...
Spot on!

I was talking to a friend who is a turbine designer for GE and showed him the web page for this turboprop last week.

His first comment was that small turbines don't last very long. I mentioned that the TBO for my Lycoming was around 2400 hours and he said, "Not even that long."
 
Love turbines but if you have to ask how much or fuel burn gives you pause it is not for you. Also these tiny turbo props and turbo jets often have very low TBO.

"These tiny turboprops and turbojet"engines that I believe you are referring to are generally model aircraft or model aircraft derivative engines. They offer a very simple design and many of them use the fuel itself, or an oil additive to the fuel for lubrication. Consequently, many of them require bearing changes every 25-50 hours. This is not a TBO as such, but folks often equate the bearing change requirement to being a TBO.

Our engine is not one of "these tiny turboprop" engines. It is being designed from the ground up to be a proper, purpose built engine for man-carrying aircraft and it is definitely not a model aircraft engine derivative. We intend to be the PT6/TPE331 equivalent in the sub-300hp power range. Through utilisation of recuperator technology, we should have a significant improvement in fuel efficiency over the larger turbine engines, and be competitive with piston engine fuel efficiency in the 150-200hp power range.


If you want a turbo-prop a used TBM 700 or Piper Meridian or Cessna Caravan is the way to go. The older ones are now $750,000 or less used. Heck you can get used Mitsubishi MU-2 or Turbo Commander cheap...

One of our aims in delivering this engine technology is to offer the experimental aircraft owner the traditional turbine benefits (size/weight/reliability/longer TBO/use JetA etc.) plus fuel efficiency not previously attained by turboprops. Even fitted with our 200hp engine, many builders will be able to build their aircraft on a $200k or less budget. When retrofitted to an existing airframe, there are going to be owners who will be able to own their own turboprop aircraft for under $150k.

Spot on!

I was talking to a friend who is a turbine designer for GE and showed him the web page for this turboprop last week.

His first comment was that small turbines don't last very long. I mentioned that the TBO for my Lycoming was around 2400 hours and he said, "Not even that long."

The Allison/RR250 which through its iterations have offered power in the range 250-450+hp has TBOs in the 2000+ hours range. The TBO is a combination of what the engine was designed for and what it can actually achieve. Our engineers have designed for a TBO of 3,000 hours and a life of at least 5,000 hours. Testing and experience in the field will determine what the correct TBO figure will be and what TBO figure we will apply to our engine.

The design of our engine incorporates well proven and well understood turbine technology. However, it also incorporates some technology that has only recently become available thanks to advances in computational capability, materials and manufacturing techniques. There are challenges associated with the development of this technology and it is overcoming these challenges which will result in the advances in turbine technology that we hope to offer. I can't say that we are there yet because we have not yet demonstrated the technology. However, we believe that we are close to being able to do so.

We have the benefit of starting with a clean sheet design. Every single component has been optimised and designed to achieve a specified performance, both as a standalone component and more importantly, as a critical element of an assembly. As we have found during the design phase, the change in performance or geometry of one component generally affects many other components. One reason our design process has taken so long (albeit short by major engine manufacturer standards) is the iterative process that is required to design the whole engine. As of now, the major iterations are completed and we are left with only minor ones.

Traditional perspectives about turbine engines are generally valid in relation to our engine, but we have enough technical differences for some of those traditional perspectives to potentially be incorrect. The architecture of our engine and the technology that is incorporated into it is not like anything that many will have seen, including existing designers of small gas turbine engines for aircraft. There are very few who could speak with authority about our engine, because very few will have the intimate knowledge of the technology that we are developing and incorporating into our engine.

It is definitely not valid to compare our engine to the AMT, JetCat etc, or even the PBS TP100 because our design and technology is so different from those products.

In the not too distant future, I will be able to confirm or otherwise that our technology works as we hope. In the meantime, my team continues the development program with vigour and determination in order to bring affordable turbine power to us enthusiasts, although I think my engineers motivations are more towards having the satisfaction of designing the most innovative small gas turbine aircraft engine out there...
 
"These tiny turboprops .... The Allison/RR250 which through its iterations have offered power in the range 250-450+hp has TBOs in the 2000+ hours range.
No argument but the TBO I am referencing is for the Sonex Jet https://www.sonexaircraft.com/subsonex/. The engine is a TJ-100 turbojet engine https://www.pbs.cz/en/our-business/aerospace/aircraftgines/jetgine-pbs-tj100 made by PBS Velká Bíteš of the Czech Republic. I recall people are also using them in the BD-5J. The TBO is not high, due to bearing replacement I recall. Is this an over sized RC jet engine. I think it more of a drone or cruise missile engine.

Allison Model 250 or now Rolls-Royce M250, (military T63 and T703) have been used in many fixed wing but even more helicopters. For turbo Prop I think they are in production again, but very expensive. As far as TBO on the 250, I assume the number you quote is progressive maintenance, section is "on condition" or IRAN "Inspect, Repair as Necessary". The question is what will wear out or time limited parts cost.

So yes if you can make an inexpensive, reliable turboprop with good BSFC great. Kit Plane or EAA Sport Aviation I recall had a RV-10 with a turbo prop, may be yours. The figures were interesting I recall. It performed about as well as a IO-540 but had more fuel burn or lower MPG...

Spot on! I was talking to a friend who is a turbine designer for GE and showed him the web page for this turboprop last week. His first comment was that small turbines don't last very long. I mentioned that the TBO for my Lycoming was around 2400 hours and he said, "Not even that long."
My two Lycomings on my Piper Apache PA-23-160, when I sold the airplane, had 2300 hours since new. The engines were replaced by previous owner with brand new Lycs before I bought it with about 1800 engine total time. They were running strong, had compression all over 75/80 and oil use about 1 qt in 8-10 hours. The secret was plane flow often, not abused and always kept oil at 5.5 Qt, no more. I'd added a little oil every few flights. Anything over 6 qts a Lyc will spit out.
 
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Dave,

Definitely looking forward to the results... And waiting patiently for my deposit number to come around.

I greatly appreciate that you are open and, from what I've seen, honest with your vision and plans.

Heck... Even the website update is something that others have promised and never delivered within their own projects. It might be a small thing for some, but it shows that you are truly trying to develop a whole company around a product that you believe will be a success!

My only dilemma is what to do when my deposit comes up and I have finally decided I might need two of your engines... :p

Victor
 
Dave----we are looking forward to the results!!!
Tom

Thanks Tom.

No argument but the TBO I am referencing is for the Sonex Jet https://www.sonexaircraft.com/subsonex/. The engine is a TJ-100 turbojet engine https://www.pbs.cz/en/our-business/aerospace/aircraftgines/jetgine-pbs-tj100 made by PBS Velk? B?te? of the Czech Republic. I recall people are also using them in the BD-5J. The TBO is not high, due to bearing replacement I recall. Is this an over sized RC jet engine. I think it more of a drone or cruise missile engine.

I understand that the TJ100 is a development of the Auxiliary Power Units that PBS built for many years for Eastern bloc aircraft. As far as I know, it was not a clean sheet design. It was not derived from a model aircraft engine so it is more complex than those simple engines, but you are correct, it's TBO is not impressive.

So yes if you can make an inexpensive, reliable turboprop with good BSFC great. Kit Plane or EAA Sport Aviation I recall had a RV-10 with a turbo prop, may be yours. The figures were interesting I recall. It performed about as well as a IO-540 but had more fuel burn or lower MPG...

The engine installed in the RV10 is a PBS TP100 which is a 240hp turboprop variant of the TJ100 turbojet used in the Subsonex. PBS hit the mark in providing some of the benefits of a turboprop engine (size, weight, runs on JetA), but for the experimental market, they missed the marks in price point (now around $130k for a 240hp engine), specific fuel consumption (cruise SFC from their own literature of 0.90 lbs/hp/hr which is twice that of piston engines - our SFC is targeted to be under 0.50 lbs/hp/hr), and reliability/TBO which have been reported to be both low.

With our engine, we hope to address all the factors that will make a turbine engine an attractive proposition for the experimental aircraft owner. Fairly soon, we will know whether we have achieved our aims or not.

Dave,

Definitely looking forward to the results... And waiting patiently for my deposit number to come around.

I greatly appreciate that you are open and, from what I've seen, honest with your vision and plans.

Heck... Even the website update is something that others have promised and never delivered within their own projects. It might be a small thing for some, but it shows that you are truly trying to develop a whole company around a product that you believe will be a success!

My only dilemma is what to do when my deposit comes up and I have finally decided I might need two of your engines... :p

Victor

Thanks for your patience Victor, as well as your ongoing support.

Bringing an engine to the market is not only about solving the technical issues to be able to offer a quality product, it's also about building a solid company around the business.

Our company has (at least) two significant priorities; the happiness and welfare of its employees and the satisfaction of its customers. We are working hard to address both these priorities. We are pretty confident that we have succeeded so far with the first priority with the small team that we have, but we know that we will have a lot of work still to do with the second priority.

I recognise that I have been guilty of not getting enough information out there to the handful of customers that we have and for that I apologise. With the lean team that we have been operating with while we undertake the development program for the engine, I have had to prioritise my time and efforts.

We have now taken steps to address the communications issue with the appointment of a Marketing and Communications Manager (Amanda) who has recently started with us. She is an absolute dynamo and has been responsible for developing our communications and marketing strategy. Hence the new website.

While the new website is currently only a landing page, Amanda is actively pursuing the development of the full website which will offer significantly more information to help a prospective customer make their buy decision. There will also be a dedicated forum which will include aircraft type specific sections for discussion around installation of our engines in specific aircraft models; ordering of engines and accessories will be done through the website; download of technical/installation manuals will be available; and there will be a restricted access dedicated section for registered owners.

We are also busy developing the infrastructure to support the engines in the field. After-sales support is probably more important than the support offered during the purchase process. Consequently, we are placing a high priority on establishing a network of approved service centres who will be able to offer high quality maintenance, repair and overhaul services.

Victor, as a gesture of my appreciation for your support as one of the handful of customers that have reserved a delivery slot, when we confirm whether you wish to accept your first engine, I will offer you the option on a second engine that will be within 10 serial numbers of the one that you have reserved now. That way if you want or need two, you can have two.

Discussing this is reminding me how much I have on my to-do list today so I'd better get on with it.

Dave
 
Oshkosh 2021

Hi everyone.

It's been ages since I updated this thread. The design process, Covid, the design process, capital raising activities, the design process, sourcing suppliers, the design process (you get my drift) have all contributed to an extended development program for our engine. Technical challenges have arisen and been overcome, compromises have been made in relation to size, weight, cost, fuel efficiency etc. but we feel that we have settled on the optimum compromise for all those factors. Consequently, we are currently completing the final analyses for the 200hp engine and prototyping of components has started, A concerted effort to prototype all components will commence at the start of September, once all the manufacturing drawings are completed.

With first engine runs targeted for the start of next year, we have decided to display at Oshkosh this year. We are not there to sell engines (that will happen next year once we have proven our product), but we are there to raise awareness about TurbAero and our turboprop engine development program so that when the time is right to start selling engines, interested people are ready to take the leap of faith and order one for themselves.
Our display is located in Booth #615 in the Homebuilt Aircraft Display area. We are literally a stone's throw from the Vans display. I extend the invitation to all who are attending Oshkosh to swing past our booth and check out our display.

At this point, I will try to manage everyone's expectations. The engine is not yet prototyped so there will not be an actual engine on display. There is a model only that will give folks the opportunity to see its size and general layout, such that they could picture the engine in their RV. The model is attached to the firewall of a small single seat aircraft and it fits ok, so no problems fitting it into an RV cowling. First run of the prototype is anticipated to occur at the start of next year, with deliveries to customers anticipated for early 2023. So yes, there is still a ways to go before anyone can have one.

I know that all you guys are RV guys, but you might find the aircraft in our booth interesting as well. It is RV3 in its style, but will perform a whole lot better.

I'm sorry I wont get to see any of you there due to the travel restrictions on us Aussies, but I wish you all a fantastic Oshkosh and I'll look forward to meeting up with as many of you as possible in due course.

Dave
 
Thanks for the update Dave, good to know how the project is progressing.

Thanks Ross.

We now have a good understanding about why it takes P&W or GE 7-10 years to develop such an engine. Ours is more complex due to the innovative technology we are incorporating and we don’t have a team of 100 working on it, so while things have taken longer than we had hoped for, we have made very positive and pleasing progress. I am really liking how it is shaping up.

Still, it’s not too long before we will be pushing the start button. That will be a real milestone on our program and here’s hoping that our first iteration is not too far off the mark of what we are aiming for.
 
I imagine the heat exchanger design and construction was a big challenge along with many other aspects. Kudos for staying at it. Can't wait for the first vid of the startup. :)
 
Development Time

Thanks Ross.

We now have a good understanding about why it takes P&W or GE 7-10 years to develop such an engine. Ours is more complex due to the innovative technology we are incorporating and we don’t have a team of 100 working on it, so while things have taken longer than we had hoped for, we have made very positive and pleasing progress. I am really liking how it is shaping up.

Still, it’s not too long before we will be pushing the start button. That will be a real milestone on our program and here’s hoping that our first iteration is not too far off the mark of what we are aiming for.

I hope this doesn't sound too blunt, but why do you believe that you can develop an engine with fewer people and in far less time than a company like P&W that literally has all the experience and resources in the world available for turbine engine development?

Skylor
 
I hope this doesn't sound too blunt, but why do you believe that you can develop an engine with fewer people and in far less time than a company like P&W that literally has all the experience and resources in the world available for turbine engine development?

Skylor

How can SpaceX possibly design and fly rockets faster than established companies like ULA and Boeing?

Just because you're big and established, doesn't mean you are the best. Lean companies that work fast and hard can come from behind, upsetting the top-heavy beauracracies that have entrenched themselves in "Thats the way we've always done it." We're flying RV's today because some guy in Oregon decided he didn't want to wait for Cessna or Piper to build a better airplane, so he did it himself. The world is full of similar examples.

Having said that though - it is pretty tough to pull off.
 
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...and

"...have entrenched themselves in "Thats the way we've always done it."..."

Sounds like a clip from about a dozen other threads on this very forum!:D
 
How can SpaceX possibly design and fly rockets faster than established companies like ULA and Boeing?

Just because you're big and established, doesn't mean you are the best. Lean companies that work fast and hard can come from behind, upsetting the top-heavy beauracracies that have entrenched themselves in "Thats the way we've always done it." We're flying RV's today because some guy in Oregon decided he didn't want to wait for Cessna or Piper to build a better airplane, so he did it himself. The world is full of similar examples.

Having said that though - it is pretty tough to pull off.

I think one of the main reason for SpaceX success is Elon's tolerance for failures in order to get ahead. Large entrenched companies are risk adverse, filled with managers who are not willing to make mistakes. SpaceX was willing to try new idea and accept the inevitable initial failures. Managers of the Boeing or Lockheed would probably get fired for doing the same.
 
I hope this doesn't sound too blunt, but why do you believe that you can develop an engine with fewer people and in far less time than a company like P&W that literally has all the experience and resources in the world available for turbine engine development?

Skylor

I don't know if it will be in far less time. The genesis of this project goes back a few years now, like 2008-2010 I think.

Sometimes large companies design by committee which is rarely efficient or quick.

I've seen numerous instances where a small group of talented people who think and work together well, turn out great products pretty quickly.
 
I hope this doesn't sound too blunt, but why do you believe that you can develop an engine with fewer people and in far less time than a company like P&W that literally has all the experience and resources in the world available for turbine engine development?

Skylor

Hi Skylor,

One of our consultant engineers has worked on a similar program with one of the big guys. He has indicated to us what a pleasure it is to work on our project for several reasons:

1. He is not constrained to thinking within the box and is loving his ability to propose innovative solutions to our challenges.
2. When he proposes a design feature or a design solution to an issue, he is given a decision about how to proceed generally within 24 hours. He indicated that the same decision when working with the major would take 4-6 weeks as it was staffed up the engineering chain for someone to make a decision, then was staffed back down the chain to convey the decision to him.

That same engineer has indicated that where we are after 3.5 years of design effort is well ahead of where the big guy would have been at that point.

If we had access to just a few extra resources, we would be 6-12 months ahead of where we are now. Covid didn't help.

We are actually very proud of what our small team has achieved in such a short timeframe.

As Airguy says, it is still a very tough gig, no doubt about it, but we have an amazing team.

As rv6ejguy points out, this project was planted in my mind in 2008 when I was searching for an engine for my Lightning Bug aircraft. I spare-timed the fabrication of a small, fuel-inefficient but cheap prototype for a circa-100hp turboprop which ran in 2015. At that time, I really recognised the potential for a high-quality fuel-efficient turboprop in the recreational aviation market and it was at that time that the decision was made to pursue a proper development program. Market and commercial research indicated that the 200hp market would be the best market to launch into. We established the corporate entity in 2016 but it took a full year+ to get the initial funding in place, and the even harder task of putting together the necessary design team with the relevant experience and expertise took another year+. I cannot stress the importance of having the right team highly enough.

So 3.5 years into the development program proper, we are where we are and it has been a fantastic effort from all within TurbAero to be where we are right now. We appreciate the support that we have received from many people.

We still have a demanding journey ahead but with the prototyping of components starting and the potential to have an engine that we are ready to push the start button on early next year, our motivation level is still incredibly high. Having the whole team being so motivated and driven to making this engine and the business a success is what is allowing us to make the progress that we are.

There is no doubt that we will run into further challenges along the way, but we will do what we have done in the past. Identify the root cause, assess the implications, develop a proposed solution, implement the solution and re-test.

As Mike Patey says, back to work!
 
Early next year is now so I was just wondering how things are going.

Oliver
They seem fairly active on their FB page, with the last update being 45m ago with their SnF booth details (NE 7+8 for anyone going). The latest update from their website was 08 Feb '22:

Turbine Aeronautics said:
We are pleased to announce that our technical program has progressed to the point where we are contracting for the manufacture or supply of several of the major components of the engine.

The components or assemblies that are now contracted for prototyping include:

Gearbox
Combustor liner
Turbomachinery components
Recuperator
Fuel nozzles


We anticipate manufacturing or sourcing the remaining components during the next quarter. While this is exciting news for our technical program, what has become more evident as COVID-19 continues to affect the world is that the supply chain for aerospace componentry has been severely disrupted. The availability of the raw materials required to manufacture our components, combined with staffing issues with the suppliers, have resulted in long lead times to get components manufactured. We are doing our best to reduce the lead times, but our timeline is now at the mercy of the supply chain.

However, this progress towards the manufacturing of prototype components is very exciting for us. After so long designing components, it is exciting for all concerned to now be prototyping these engine components.

As components are manufactured, we will provide details through our social media channels so please keep an eye on our Facebook page and YouTube channel.

For those that have been enquiring about propellors to be used on the Talon, we had intended to keep the engine less complex by offering only an electric constant-speed propellor system. However, based on feedback from customers, we have now made the provision for a hydraulic constant-speed propellor to be used on the engine. Our new gearbox design is a two-stage planetary reduction design, and through an accessory drive port, we now have the provision to install a hydraulic governor for propellor control. The manufacturers of our propellers have still to be finalised.
 
Thanks KRviator, your post sums it up pretty well.

The last 6 months have seen a lot of activity refining the design in anticipation of manufacturing the prototype. The gearbox is now a very neat 2 stage planetary design and also has the provision for a hydraulic governor.

We have also added the provision for a mechanical fuel pump (it was previously 2 x electric pumps only) that will offer a limp home mode in the event of a total electrics failure (resulting in a loss of fuel pumps and FADEC). We plan a lot of redundancy in the electronic fuel system, but having a good old mechanical backup will provide more peace of mind.

The manufacturing process for our recuperator component has necessitated a slight change in its configuration which has changed the look of the engine slightly. It still has the same cross section / diameter but is not quite so streamlined. It is still very low profile.

Parts are being made at the moment. We hope to have some videos/photos from our suppliers that we can publicise shortly to show that we are now transitioning from vapourware to hardware. That is certainly exciting for my team.

We definitely want to get our engine into the RVs. That would just be the perfect combination of airframe and engine. We will have more news on an initiative along those lines over the next few months.

Thanks for your interest.
 
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