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Plans for diesel TB20 - great article.

Great article in French Aviation et Pilote magazine of January 2015 on new venture with plans for a diesel future for TB20. STC for Continental CD 230 first, then new composite wing and new production line in Morrocco.

Last Edited by Nestor at 31 Dec 21:54
LFLY, France

A google translation from the wording in that link

doesn’t suggest to me that F-GOOD is actually a diesel.

In any case it’s interesting to see. I am aware of several approaches (no details ) to Socata to restart production but none got anywhere. Reportedly Socata were asking too much money, and no proposal would work unless the spares business was included, and the spares business is lucrative!

Administrator
Shoreham EGKA, United Kingdom

It’s not about restarting the TB20, it’s about modifying existing TB20s to use the Continental licensed version of the old SMA engine. That is a pretty poor engine with no power at altitude and will not yield a good product. Limiting this to the GT makes it even less viable as there are not many out there.

Wonder where the mention of a composite wing came from? The industry trend is towards composite fuselages (for easier manufacture) not so much composite wings, and particularly not constant chord composite wings.

Socata have had a TB20 flying with the old SMA engine for probably at least 10 years. I have some photos somewhere of the engine installation (very messy).

It’s interesting but so much depends on the cost. All the diesel retrofits I have thus far seen have been priced for the ~500hr/year training market, which is the obvious “low hanging fruit”, not for private owners, not even the highest hour private owners.

For the cost of the retrofit you could buy enough avgas for more years than the average private TB owner has left to fly, delivered in a bowser from the Istanbul Aero Club

There are about 200 GTs around, depending on which type interests you – see here. Serials start at 2000. For an STC, that’s not too bad, but the Big Q is what % of these people will put their hands in their pockets. GTs still go for a lot of money (typ. €150k for a well equipped one) so the owners of those should be more motivated to keep them going.

Administrator
Shoreham EGKA, United Kingdom

I followed very closely the development of the SMA over the years and the “real world” result is very dissapointing.

IMHO, the ONLY reason to go to a compression ignition powerplant is to burn JetA1 where AvGas is unobtainable.

Some of the things that the diesel promoters seem to leave out :

- Cooling drag : Have a look at the COPIOUS cowl inlets / exits on a SMA powered Cessna 182 to get an idea …
- Vibration: Props take a helluva beating when bolted to SMAs, expect more failures & shorter life.

I’m not convinced that the diesels will displace gas burners in the short – medium term.

Last Edited by Michael at 01 Jan 11:49
FAA A&P/IA
LFPN

Hi guys,
Again, on this special day, let me wish you and your relatives a very healthy, happy and prosperous 2015

1) I thought this article would be interesting for some of you, in particular Peter for TB20, and I encourage you to buy the magazine. Article spans across 8 pages and gives a lot of information on this private venture, its creator, the plans, as well as great pictures supporting the idea that this platform is a valid choice for life extension.

2) Your questions or objections are somehow answered in the article or in other articles on the same subject:

@Peter – doesn’t suggest to me that F-GOOD is actually a diesel.

You’re right, F-GOOD is one of the latest TB-20 GT produced. It is based in Paris-Lognes (LFPL) and belongs to Jean-Pierre Rigaud, a professional musician. The second part of the article is a test flight report and discussion on how well suited a platform is TB-20 for such a project.

@Peter – I am aware of several approaches (no details ) to Socata to restart production but none got anywhere. Reportedly Socata were asking too much money, and no proposal would work unless the spares business was included, and the spares business is lucrative!

TB-20 ECOJET isn’t a Daher-Socata project but a private venture by a new company, AIRtbo Concept (Aircraft Industry Renewal for Training and Business Organizations) created by Jean-François Sochor, former Socata test pilot and specialist of the airplanes built in Tarbes. The company is organized around a production factory in Tangiers, Morrocco, and a design, engineering and test center in Toulouse. Toulouse center will receive EASA’s DOA and will be the prime contractor.
Project is split in two phases:
Phase 1: STC for Continental CD230 retrofit for TB20
Phase 2: production relaunch and new composite wing
Funding from private investors has been secured for phase 1. Start of phase 2 is contingent on phase 1’s success.
Daher-Socata is expected to join the project for phase 2.
One sentence is important: “Production relaunch in Morrocco will induce a decrease of spare parts prices, which is what (TB-20) owners are waiting for.”

@achimba – That is a pretty poor engine with no power at altitude and will not yield a good product. Limiting this to the GT makes it even less viable as there are not many out there.

The retrofit is for all TB-20, not just GT. The example cited in the article is F-GOOD which is a GT.
Contrary to what @achimha says, the article writes “…above all (the Continental CD 230 engine) maintains 100% power up to FL125 whereas the Lycoming only produces 60%.” It seems to be a good powerplant for general aviation. Severeal dozens Cessna 182 have been retrofitted with the original SMA SR 305-230-1 engine under the SMA STC, and they’re almost impossible to buy because their owners want to keep them. Here is an AVWeb video report



on flying an SMA-powered Cessna 182. In addition, a new version of the same engine has been chosen by Cessna for the TURBO 182T SKYLANE JT-A.

@silvaire – Wonder where the mention of a composite wing came from? The industry trend is towards composite fuselages (for easier manufacture) not so much composite wings, and particularly not constant chord composite wings.

Article writes “Choice for the square-shaped wing dates back from 1972. It was aimed at reducing production costs: identical wing ribs, same wing for all versions of the product range, same wing area from TB-9 of 1060kg to TB-20 of 1400kg! Even if the RA16-3C3 profile gives good results at low speeds, with sound stalls, the square shape, the constant thikness profile, the wing area and aspect ratio are severe handicaps preventing higher speeds. Contemplating a modification is therefore mandatory in order to significantly improve TB-20’s performances and make a new plane of it. This could be obtained cost-effectively, based on the existing profile, from the undercarriage-attachment wing spar, by increasing the wing area (+1.5 / 2 m2), by creating a tapering by reducing the chord and thickness and adding winglets, without modifying the flaps or ailerons. Some 9kt could be gained, but could prove costly in terms of flight testing and spin-exit testing. But adding a new wing to the new engine, we reach the interesting value of 180KTAS, which are 3NM per minute of flight which the Cirrus and other Mooney travel.”

@Peter – Socata have had a TB20 flying with the old SMA engine for probably at least 10 years. I have some photos somewhere of the engine installation (very messy).

I think the diesel TB20 you mention, registered F-WQRQ, isn’t Socata’s but SMA’s. It’s the flying testbed used for SR 305-230-1 engine development by SMA. I don’t think they designed it with a STC in view (they never applied for one), unlike the Cessna 182 STC which was quite well engineered.

@Peter – There are about 200 GTs around, depending on which type interests you – see here. Serials start at 2000. For an STC, that’s not too bad, but the Big Q is what % of these people will put their hands in their pockets.

Article writes: “…since production stop 10 years ago, there are at least 800 TB-20 in flying condition in the world….” and “…the TB-20 is lacking on a market dominated by Cirrus, Cessna and Diamond and some others, failing a better solution!”

Last Edited by Nestor at 01 Jan 17:50
LFLY, France

Nestor, thanks very much for translating the discussion on the wing design, very interesting!

Happy new year to all

Many thanks for the translation, Nestor

I wish them luck.

The retrofit cost will obviously be the most interesting thing.

Regards Socata spares, I believe many are already made in Morroco, where Socata have had facilities for many years.

I am surprised only 800 TBs are flying, because over 2000 were made and I find it hard to believe 1200 of them have been scrapped or crashed.

Administrator
Shoreham EGKA, United Kingdom

Seriously doubt that ANY significant wing design change could be financially viable. The discussion here is just journalistic rhetoric .

re. " there are at least 800 TB-20 in flying condition in the world"

There are a surprising number of TB20s that are getting parted out because they are not economically viable to repair/maintain in today’s depressed used acft market. The older TB20s have no where near the market value of say a Cessna Centurion of the early 80s vintage.

Last Edited by Michael at 01 Jan 19:49
FAA A&P/IA
LFPN
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