Solar T-62 turbine

Turbo-Tom

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Joined
Feb 22, 2009
Messages
18
Location
Usingen
Akoschier -

no, so far I haven`t got an exact figure for the price. It also depends on the quantity of the manufacturing batch. I don`t expect to make more than twenty pieces a time since also the components are all high quality and consequently expensive. As a rough estimate, I guess a complete system including control panel and MIL connectors would be slightly more than 1000 Euros.

Stan -

no sorry, my engine control system unfortunately cannot change the thermodynamics of the Solar turbine. And this is responsible for the fuel economy. That`s also the reason that I question the statements of Innodyn, by just adding a state-of-the-art automotive-derivative fuel injection system to cut the fuel consumption by almost half... In one liter (or gallon...) of fuel, there`s only so much chemical energy stored that can be released by combustion. The Solar has an air mass flow of roughly one kilogram per second. To heat it to, say, 900C just before it enters the NGV (turbine nozzle guide vanes), just a certain amount of thermal energy is required which is released in the combustor by the burning fuel. And the combustor of this old Solar engine is quite efficient, I`m sure at the design point of the engine the combustor is about 99% efficient. This means, only about 1% of the injected fuel will leave the turbine unburnt (and hence is wasted). Modern engine`s combustors won`t perform mach better. The only way to a better efficiency is to increase the engine`s pressure ratio (the solar has a PR of round about 3.7) and turbine entry temperature. This both means basically stressing the materials higher, and consequently using more modern alloys for the critical components. By the way, this is exactly what a friend of mine and I are doing at that time, designing and constructing a state-of-the-art turboshaft in the same power class as the Solar. Yet, all the other figures will be completely different. We will reach the efficiency that Innodyn claims, the engine including reduction and auxiliary drive gearbox will weigh around 25kg and we will have an electronic fuel control system with a mechanical 100% governor as back-up. Many of the components for our prototype batch of five engines are already finished while we`re still struggling with some others. Especially the fuel control unit requires extremely close tolerances. So far, we already spent a small furtune on the stuff, working already four years on the design and will probably spend another fortune until the first prototype runs... Yet, I`m sure in the end our effort will be rewarded, also commercially. FYI, I attached a photo of our compressor wheel, custom milled from a forged billet of TiAlV4 (a special high-strenght titanium alloy) which is only 125mm in diameter and will run at 100,000 rpm (this is a whooping 650m/s at the blade tips). But that`s the only way to get a high enogh pressure ratio to achieve the desired fuel economy...

When the time is ripe, I´ll post more information on that new motor...

All the best,
Thomas
 

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Gyro_Kai

Senior Member
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Nov 29, 2006
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3,270
Location
near Frankfurt, Germany
Aircraft
MT-03, Calidus (rent)
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about 150
Thomas,

a very interesting project. Is there a chance to visit you and have a look at it?

Kai.
 

C. Beaty

Gold Supporter
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Apr 16, 2004
Messages
10,101
Location
Florida
The pressure ratio, or more correctly, the expansion ratio is the bottom line in any heat engine from reciprocating steam engines through diesels to steam and gas turbines.

The more the working fluid can be allowed to expand, the cooler the exhaust and the more of its heat converted to mechanical energy.

The diesel cycle, for instance, is less efficient than a spark ignition cycle but the diesel wins overall because it can be operated with an expansion ratio of ~16:1 and therefore has a cooler exhaust.
 

Turbo-Tom

Newbie
Joined
Feb 22, 2009
Messages
18
Location
Usingen
Kai -

of course it is possible to come over to have a look, though currently I`m in Moscow and I`ll be back only in about four weeks. I noticed you`re located close to Frankfurt, I live in Usingen, 30km north of Frankfurt. Yet, most of the "hardware" is in my friend`s CNC workshop in Renchen-Ulm, a few minutes from Baden-Baden. If you like, I can show you the theoretical side of our project, if you want to "touch" something, we`ll have to go to visit my "buddy"...

Cheers,
Thomas


P.S. Wo und was fliegst Du eigentlich? Ich bin soweit nur mit Starrflüglern unterwegs und zwar mit ULs und fliege in Reichelsheim (EDFB). Wenn es in Deutschland mal eine UL-Klasse "Hubschrauber" gibt, bin ich nochmal dabei... Für Autogyros konnte ich mich bislang noch nicht so richtig erwärmen ;-)
 

akoschier

Junior Member
Joined
Sep 10, 2005
Messages
126
Location
lynnfield
Aircraft
helicycle
Total Flight Time
55
Thomas,

When you get to making FADEC's let me know, I might want one.
I assume your unit uses the fuelvalve,startfuelvalve,accelfuelvalving and torque motor of the GPU.
As for higher P/P- as you certainly know this can also be had by increasing the exducer diameter and redesigning the diffusor. To stay in the case OD it will also need a new combustor. A new, smaller turbine nozzle would be required as well.
That's what I would have done to upgrade the T62 without having to build a complete new machine. Your smaller wheel though will be lower total weight.
regards,
avk
 

Turbo-Tom

Newbie
Joined
Feb 22, 2009
Messages
18
Location
Usingen
Akoschier -

I`ll let you know when I`ll have ECUs available... :)

By the way, I don`t consider it a good idea to try to modify the T-62T-32 to improve efficiency. Your proposal of course would be an appropriate way, but it means replacing at least the compressor wheel, diffuser and NGV. This will definitely change the dynamic characteristics of the rotor, and, especially in cantilevered designs like the Solar, this may very quickly lead to disaster when the shaft-critical RPM comes too close to or even within the range of the actual working RPM range. Even if it may require more effort for the lubrication system, I favor for a high-performance engine a layout with at least one bearing between compressor and turbine. That`s how we`ve designed our engine. It`s really amazing to see how small all the stuff is... When adapting this more modern aerodynamics to an engine the size of the Solar, it would easily produce 300hp...

As an answer to a posting on the first or second page of this thread, have a look at the following photos. They originate from an engine that we bought in a batch of three (...for the price of one :rolleyes: ...). They show the result of a seized roller bearing, probably as a result of insufficient lubrication, at rated RPM. As you see, the turbine wheel stub, the torque transfer bolts and the tie bolt as well all are sheared. The turbine wheel was free to run havoc inside the NGV. Nevertheless, no shrapnels or high-energy projectiles were leaving the engine, actually, externally it still appeared to be in excellent condition (except it wouldn`t turn over any more...). I cannot guarantee but I`m quite optimistic that at rated speed plus maybe ten pecent, even a catastrophic failure of the turbine wheel will be contained by the turbine shroud and surrounding material. I have heard of a single case (yet I`m not sure that it`s true since this is not first hand information) of a T-62T-32 turbine actually disintegrating catastrophically with shrapnels and all this nasty stuff flying around, and this was when the "operator" tried to control speed manually by moving the power lever with his hand and the engine running off-load. It probably overspeeded by 50 or 60% when the turbine wheel let go... But if a reliable governor is controlling the engine (and a back-up fuel valve is installed, which is also controlled by the supervisory circuitry), then I think its virtually impossible to encounter a really dangerous situation with a T-62T-32.

All the best,
Thomas
 

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Turbo-Tom

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Joined
Feb 22, 2009
Messages
18
Location
Usingen
"Cyprus Connection"

"Cyprus Connection"

I just returned from another trip to Cyprus to help my friend Platon to modify his Ultrasport 496T to the latest configuration. His machine was the first 496 to be converted to the Solar T-62T-32 and many of the solution had prototype character and couldn't be considered the safest possible.

Also, our new coaxial centrifugal clutch design cannot be improved in terms of simplicity, reliability and compactness.

Moreover, I was supposed to work on the governor/sequencer software to implement many safety features like automatic engine relight, EGT-limited, scheduled rotor spool-up and improved engine cold-start sequencing. It also turned out that a small modification of the hardware was neccessary to make it less sensitive to internal noise from the 12V - 24V DC/DC converter.

To cut a long story short, the result was a package that's better than ever and the other two systems that are already in use will have to be modified accordingly.

There's one issue that affects safety of all applications of the Solar T-62T-32engine which I would like to address here: The fuel filter that's located inside the turbine's fuel control unit (FCU) is sealed by an O-ring in a radial groove at the filter's base. The taper of the mating cylindrical surface in the FCU body may be a little short to help guiding the O-Ring in during reassembly of the filter. As a consequence, the O-ring can easily be sheared if reassembly isn't done carefully. If sheared, the separated part of the O-ring will be located in the cavity around the filter element. Since fuel flow through the filter is inside-out (uncommon for any filter application), the loose part of the O-ring is downstream of the filter and can (and will) be flushed away be the fuel right into the internal ducts and components of the FCU. Actually, we had two FCUs both working erroneously because some O-ring debris had been stuck in the fuel pressure limiter valve and kept it stuck in a (partially) open position. One unit was initially working correctly and during acceleration of the helicopter's rotor system (and thank God not later...) it caused a severe loss of power, while the second FCU wouldn't produce enough pressure to be able to start the engine.

We learned from this that whenever we will put a Solar engine, regardless of its origin, on an aircraft, the FCU will be stripped down, inspected and cleaned and all the O-ring seals will be replaced. Moreover, when checking the (re-usable) FCU fuel filter, we will always replace the O-ring and very carefully place it back into its cavity and, once seated, make absolutely sure that the O-ring had not been sheared. Also it should be kept in mind that a healthy Solar FCU will prime itself as long as there's a fuel boost pump located upstream and switched on. There's no need to remove anything from the FCU in order to bleed the air from it. If it won't prime, it would have to be serviced anyway.

I added a few photos of our findings and also of the helicopter ready-to-fly.

Cheers,
Thomas
 

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don hillberg

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Jun 2, 2008
Messages
11
Location
Ventura Ca
Manual /Auto governed control

Manual /Auto governed control

The T-62-T32 was designed as a Gen set engine-But the lines come from a small helicopter ,the Del Mar it had a solar powerplant,The T-32 was designed as a cycle limited engine,in 1998 the service history of this powerplant was so good it became a conditional engine with a hot end inspection every 600 hours,The main reasion it was chosen for the jet Exec,was the service life and instructions for continued use,now I have a manual control that works well with the exec with a solar powerplant,and having an electrical failure is a no brainer(the fuel valve is also manual)
 

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Turbo-Tom

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Feb 22, 2009
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Usingen
Don-

if I understand correctly, there isn't any means to protect the engine from overspeeding when it's in manual mode, right? Your arrangement of levers makes me assume that you've got both a maximum as well as a minimum control for the throttle lever on the FCU. So your system will be able to cope with both a blown drive circuit (Torque motor under power continuously) or a broken return spring, as well as the torque motor not powered as all condition. Quite a clever design!

Yet, I think the probability of a failure in the electronics or the wiring -- if done properly -- is very low. My new electronics addresses the possible problem of a failure in the electrical power supply by adding a (small) backup battery only for the engine systems. In my opinion, this system is pretty safe and I'm not sure if another (manual) backup system is still neccessary. Especially, if the pilot isn't familiar with using a manual throttle (sorry, being only a fixed wing pilot, I may be sounding ignorant regarding this issue), he may be a little overstrained with the situation.

In a helicopter, the best combination would be an electronic system for "convenience" while having a mechanical (flyweight) governor for emergency situations, limiting the engine RPM just slightly above 100%. Actually, that's exactly what I designed for our "future engine". I won't comment it, but you will find a rendering of this unit attached to this posting. About 70% of the components are already manufactured and I hope I'll have it assembled end of next month, ready for testing...

Cheers,
Thomas

P.S. I forgot to ask, has anybody got or does anybody know about any experience with the T-62T-32A engine? I remember to have read about somebody having problems with this version, but it should safe about 25% of fuel compared to "our" T-62T-32. Any input is welcome!

P.P.S. I just added a new section to my web site concerning our latest T-62 conversion. Have a look here if you like: http://www.turbinemuseum.de:80/Gasturbines/Solar_T-62/The_Story_Goes_On/the_story_goes_on.html
 

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Turbo-Tom

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Joined
Feb 22, 2009
Messages
18
Location
Usingen
Finally, almost one year after my last contribution to this thread, I managed to start production of the ECUs. The system has undergone some improvements again, finally offering more versatility and (very nice to have) a firmware update capability by built-in USB interface. The same interface provides download of the logged engine data and statistics. I decided to use a specifically machined, hermetically sealed aluminum enclosure to make the whole system completely water-tight, including the connectors. The system can be configured to work both with the standard (normally closed) as well as the modified (normally open) fuel valve. There are many diagnostic features included, but it would take too long to mention them all here... I guess an ECU for a Solar T-62T-32 cannot get much better than that.

Cheers,
Thomas
 

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Arnie Madsen

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Mar 14, 2007
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Southport Aerospace - Manitoba Canada
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Bell 47 G2
Very nice workmanship and detail Tom.

I am not qualified to comment on the ECU but my mind exploded way off to left field thinking maybe the Helicycle factory has been waiting for this component for 2 weeks to include with Stan's turbine. :)

I do not require a reply Tom , and quite frankly it is none of my business who will be using your components. I do wish you great success with your plans.

I admire people like you who have the brainpower to work on these things and make improvements.

Arnie.
 

Turbo-Tom

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Joined
Feb 22, 2009
Messages
18
Location
Usingen
Actually a batch of ten of these ECUs will directly be used for Utrasport 496 conversion kits for which we also provide many of the mechanical parts. As far as I know, seven of these conversion kits are already pre-ordered. Another five ECUs will be sold to individuals who convert Rotorways, a HeliCycle and some others who are working on completely new projects and just need to get their Solar turbine running.

Without this demand for the ECUs, I wouldn't have started the production run, and I'm sure once the system shows up on one of the major meetings, many turbine enthusiasts will be convinced of the benefits of this ECU over the "traditional" industrial governor approach.

Stan - I hold my thumbs that your patience to wait for your engine will soon be rewarded and progress will be fast afterwards.

All the best,
Thomas
 

Turbo-Tom

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Joined
Feb 22, 2009
Messages
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Location
Usingen
Stan -
I'm sorry I have to disappoint you regarding the fuel consumption - it won't change (to any significance), whatever kind of electronic governor or ECU you use on a given turbine engine. Turbines behave very different from recips, where a clever ECU can save considerable amounts of fuel. A turbine is better compared to an oil-burning home-heating furnace than a recip. Basically, it's as simple as that: you need a certain fuel flow to heat a certain amount of air in a certain time by a certain temperature differential. Anybody who's claiming something else is, well, not exactly telling the truth :lie: .

To make a turbine engine more fuel efficient, you can either increase pressure ratio of the compressor and at the same time increase the gas temperature at the entry to the turbine stage, or add some heat exchanger device to transfer as much of the exhaust heat as possible to the compressed air after the compressor (or both - to some extent that is...). Which means you have to design a new engine.

When I designed my ECU, I rather focused on convenience (fully automatic "push-button" start, status monitoring during operation and single indicator light signalling), safety (integrated backup battery system, RFI shielding and doing completely without external pots and the associated low-signal wiring) and monitoring/data logging to be able to do serious condition monitoring and fault/problem analysis of the whole power plant system. I also intended to keep as much of the electrical / electronic stuff out of reach of the "average" homebuilder (please don't take that as an offense, it's just that I've seen too many "homebuilt" crimped or soldered wire connections - and sometimes even combinations of both...).

I will ask those homebuilders who use my ECU to publish their experiences and findings, and it may also be possible to have a look at a few helicopters with my ECU during major fly-ins in not too distant future.

I really don't want to "talk" anybody into buying one of my ECUs, if there's an opportunity to have a look at a ship with this system, just go and find your own opinion about it. :)

All the best,
Thomas
 

hillberg

Super Member
Joined
May 24, 2010
Messages
2,732
Location
Low Earth Orbit
T-62

T-62

:flame:A compressor wash is used on the PT-6-3DF to bring it back to specs As for the T-62 T32 it is what it is,a nice way to blow smoke.....and cash.......still fun,
 

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turbochris

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Joined
Apr 20, 2012
Messages
8
Location
Grovetown GA
Hi Thomas!
I was just talking about you at Bensen Days! MY stuff is running pretty good, it would be a good time for you to come visit!

Chris
 
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