Turboprop conversions – built and unbuilt

For better performances several designs were selected for a turboprop conversion during the last decades. Some of them were realised, others weren’t. I collected the names of a few of them, but I’ve forgotten the most of them during the last years. Now I discovered them in an old file and I’m interested to get more details incl. illustrations. I notice the references, but most of them are not part of my collection. Who can help to pick up the trail and add details and further designs?

An example for a converted turboprop Su-26 is attached. It was shown in Oshkosh.

About 20 years ago, I remember someone replacing the IO320 in an aerobatic biplane with an Allison 250, same weight but double the horsepower, and having quite a time with it.

This Sukhoi Su-26 has been retrofitted with a Walter M601 turboprop.
http://www.airplanezone.com/Oshkosh/Scrapbook2003/page111.html
Not sure if OKB Sukhoi and Su-26 chief designer Vyacheslav Kondrat'ev (now Yakovlev's employee) would be happy about this cadavre.

Hi boxkite!

I know that you're looking for turboprop conversions for certain aircraft, and in investigating the PBY line I did find a four-engine conversion (which I've posted in the attachment below), however I can't seem to find any photos of a turboprop conversion for the PBY although in the places I've checked the question about this does seem to pop up.

I'll keep looking and I'll post it asap if I can find it.

Chuck

Turbo prop conversions ? ok !

Here's a conversion of the Nord 1100 Ramier with an Astazou engine,
a one-off .

Please more . (Danke, Jens!)

You want it, you get it !
Converted by Turbomeca itself, the good ol' Do 27, fitted with an Astazou:
(from Aviation-Week_1961-10-17 )

Thank you, Jens. And here is another one.

Garrett-AiResearch converted a Comanche 400 into a turboprop aircraft.

Caption: “Long-nosed Comanche 400 is owned by Garrett-AiResearch, and powered by their TPE 331 turboprop engine. Company pilot Jack Womack flew it to a new altitude record for light turboprop aircraft, reaching 41,320 feet in 70-min.”

SOURCE: „Air Progress“ September 1968 (pg 12-13)

What’s the correct/official name of this conversion?
Does anybody have a better picture without a fold?

boxkite said:

Thank you, Jens. And here is another one.

Garrett-AiResearch converted a Comanche 400 into a turboprop aircraft.

Caption: “Long-nosed Comanche 400 is owned by Garrett-AiResearch, and powered by their TPE 331 turboprop engine. Company pilot Jack Womack flew it to a new altitude record for light turboprop aircraft, reaching 41,320 feet in 70-min.”

SOURCE: „Air Progress“ September 1968 (pg 12-13)

What’s the correct/official name of this conversion?
Does anybody have a better picture without a fold?

Click to expand...

There is, to my knowledge, no formal name for this conversion. It was done on an experimental license and Garrett used the aircraft as a flying test bed in addition to the converted Invader and the later converted On-Mark Marksman they used as three-engined flying test beds (the last two had the turboprop installed in the nose - which led to one exceedingly long takeoff run the time teh pilot forgot to take the turboprop's propeller off the locks).

Turboprop conversion of DC-3 for Columbian police (Basler BT-67).

Matej said:

Turboprop conversion of DC-3 for Columbian police (Basler BT-67).

Click to expand...

It was even used in Antarctic by ANI (Adventure Network International) private extreme tourism company for shuttle flights from Patriot-Hills base camp, but was destroyed by snowstorm in late 2002 (thus pissing me off the ability to fly on it)

The great source of information about BT-67: http://www.baslerturbo.com/

This one is conversion

JB-17G from 1945 was civil and USAF test-bed for an added 6000hp P&W XT34 "Turbo-Wasp," Wright XT-35, Wright R-3350, and Allison T-56 POP: 3 [N5111N, 44-85747, x]. When they realised, that the turboprop can power the plane itself, the rest four engines were removed. While results were encouraging, the armistice and dawn of the jet age curbed the project.

Matej,

Is that final pic (without wing engines) real or a photoshop creation?

Regards,

Greg

Yes Greg, its real. I found some additional info here:

http://www.airtoaircombat.com/background.asp?bg=683&id=63

And next is KJ-1 AWEC, chinese copy of T-4 AEW equipped with turboprop engines.

Matej,

Sorry to be pedantic, but that article doesn't actually say that the wing engines were removed. I was aware of the JB-17G engine testbeds and agree that they flew soley on the power of the nose engine - but this was with the wing engines simply turned off, not removed altogether. Can you confirm that the wing engines were actually removed and the aircraft subsequently flown in that configuration?

Regards,

Greg

To be pedantic is sometimes a good advantage, so no need to sorry. Well, I searched for the base of my information and its older magazine called "The world of science and technics" from 1993. This is the only source where I read about its removal and I was never thinking about if it is real or not.

I failed to find this specific information on Google so the conclusion is, that I have not any undisproved confirmation.

Do you mean the JB-17G_Turbo2.jpg picture above (in flight) is a fake photograph? ???

I suspect it is a fake, but would happily be proven wrong.

Regards,

Greg

And I would happily be proven right, or, if someone have a
better source, than Cuny, even to be wrong:
That's, what I thought the single engine modification of
the Nord 1500 Norèclair would have looked like with
a RR Clyde. It was envisaged as a tanker a/c, but I've
only the desicription of it.

... and another one found today in air & cosmos '68 :
A turbine powered version of the Cessna O-2:

Jemiba said:

... and another one found today in air & cosmos '68 :
A turbine powered version of the Cessna O-2:

Click to expand...

Didn't Conroy propose a single-engined turboprop conversion of the O-2/Model 337 with a Garrett TPE331 in the nose and with the back end reconfigured to side-hinged clamshell doors like some C-119s?

Yes: Conroy Stolifter.

Any comments regarding this B-17(?) conversion? I found it in "Brandbekämpfung aus der Luft" (= airborne firefighting), a new German book written by Wolfgang Jendsch (ISBN 978-3-613-02787-9).

It looks like a turboprop engine replacing the outer port side piston engine ...

The unidentified engine looks like an RR Dart, and behold...

http://www.warbirdregistry.org/b17registry/b17-426107.html

I think the single-engine B-17 is a fake. Single-engine flying test beds (although they have existed, such as the P.24 Battle) are a bit of a contradiction in terms, since the idea is to fly an unproven engine in a way that a failure is not flight-critical.

http://www.warbirdregistry.org/b17registry/b17-426107.html

Click to expand...

Now I understand the reason mentioning this conversion in a book on fire-fighting aircraft: "Crashed while fire bombing, Dubois, Yellowstone Park, WY, Aug. 18, 1970".

Thanks for the URL, LowObservable.

Matej said:

Turboprop conversion of DC-3 for Columbian police (Basler BT-67).

Click to expand...

BT-67s are actually pretty common...except for this one:



A three-engine turboprop DC-3 used as an engine testbed.

More rare than the BT-67 is the Conway Dart conversion:

http://www.airliners.net/open.file?id=0731872&WxsIERv=Pbaebl%20Gheob%20Guerr&Wm=0&WdsYXMg=Gheob%20Guerr&QtODMg=Cnevf%20-%20Yr%20Obhetrg%20%28YOT%20%2F%20YSCO%29&ERDLTkt=Senapr&ktODMp=Whar%201969&BP=0&WNEb25u=Wnpdhrf%20Yvraneq&xsIERvdWdsY=A4700P&MgTUQtODMgKE=Cnevf%20Yr%20Obhetrg%20Nve-fubj.%20Gheobcebc%20pbairefvba%20bs%20Qbhtynf%20QP-3%20jvgu%20gjb%201740%20uc%20Ebyyf-Eblpr%20Qneg%20Zx.510%20ratvarf.%20Svefg%20syvtug%20ba%20Znl%2013.%201969.&YXMgTUQtODMgKERD=2255&NEb25uZWxs=2004-12-13%2000%3A00%3A00&ODJ9dvCE=&O89Dcjdg=4903&static=yes&width=1012&height=719&sok=JURER%20%20%28%20cubgb_vq%20%3D%20%271217772%27%20BE%20cubgb_vq%20%3D%20%271156516%27%20BE%20cubgb_vq%20%3D%20%271122205%27%20BE%20cubgb_vq%20%3D%20%27969508%27%20BE%20cubgb_vq%20%3D%20%27945176%27%20BE%20cubgb_vq%20%3D%20%27925503%27%20BE%20cubgb_vq%20%3D%20%27731872%27%20BE%20cubgb_vq%20%3D%20%27614829%27%20BE%20cubgb_vq%20%3D%20%27547659%27%20BE%20cubgb_vq%20%3D%20%27311776%27%20BE%20cubgb_vq%20%3D%20%27219279%27%20BE%20cubgb_vq%20%3D%20%2778340%27%20BE%20cubgb_vq%20%3D%20%279067%27%29%20%20beqre%20ol%20&photo_nr=7&prev_id=0925503&next_id=0614829

A Do-24 has also been converted to use PT-6s

Jemiba said:

... and another one found today in air & cosmos '68 :
A turbine powered version of the Cessna O-2:

Click to expand...

I know they've been talking at Adam Aircraft about a turboprop version of the A-500, also with the engine up front and clamshells at back.

I also know that there was a project to convert 337s into turboprop unmanned surveillance drones as testbeds. Here's an example, but it looks like it has a piston engine:

http://www.airliners.net/open.file?id=0785456&WxsIERv=Prffan%20337U%20Fxlznfgre%20%28zbq%29&Wm=0&WdsYXMg=HFN%20-%20Anil&QtODMg=Znevan%20Zhav%20%28BNE%29&ERDLTkt=HFN%20-%20Pnyvsbeavn&ktODMp=Sroehnel%2015%2C%202005&BP=1&WNEb25u=Cngevpx%20Zbena&xsIERvdWdsY=A84AK&MgTUQtODMgKE=Jubn%21%20N%20Fxlznfgre%20jvgu%20ab%20sebag%20ratvar%21%20Bar%20bs%20gjb%20va%20gur%20jbeyq.%20Guvf%20vf%20bar%20bs%20gur%20htyvre%20nvepensg%20V%20unir%20frra.%20Abg%20fher%20ba%20gur%20fcrpvsvpf%2C%20ohg%20vg%20vf%20orvat%20hfrq%20sbe%20haznaarq%20syvtug%20grfgf%20%28lrf%2C%20gurer%20vf%20n%20cvybg%20va%20guvf%20bar%29.%20RBF%20300Q%2075%2F300zz%20VF&YXMgTUQtODMgKERD=13112&NEb25uZWxs=2005-02-27%2007%3A43%3A03&ODJ9dvCE=&O89Dcjdg=33701874&static=yes&width=1200&height=812&sok=JURER%20%20%28%20cubgb_vq%20%3D%20%27785456%27%29%20%20beqre%20ol%20&photo_nr=1&prev_id=&next_id=NEXTID

Also, a T-28 turboprop:



and perhaps the most bizarre turboprop of them all: the XF-84 Thunderscreech!



http://en.wikipedia.org/wiki/XF-84H

Consolidated turboprop PB "Canso"

Click to expand...

Now I know a source and the company which planned the conversion of the Turbo-Canso - Avalon in Canada.

Unfortunately I don't have either the JAWA 85-86 (page 18), the JAWA 86-87 (page 19) nor the JAWA 89-90 (page 18). What is the essence of the description in the JANE'S? Did the company 'materialized' the project finally?

The three-PT6 Dak was not a testbed, it was serious: Conroy Tri-Turbo-Three, demoed at Paris in the 1970s (75, 77 or 79). Before the Starship/Avanti/other 1980s projects there was no PT6 big enough for a twin. I always thought of it as a 700 shp windshield wiper.
Conroy was also responsible for the turbine 337 with rear doors - STOLifter, http://www.fortunecity.com/skyscraper/cairo/61/n1414g.jpg. And I think Cessna did the O-2TT (O-2 Twin Turbine) with Allison 250s.

The three-engined Dak was the Tri Turbo-3. The idea was that the third, central PT6A-45 would be "used mainly for take-off and high-speed cruise, being shut down and propeller feathered for economical cruise."

source: Bill Gunston, The Illustrated Encyclopedia of Propeller Airliners, Phoebus, 1980

Boxkite: thanks mentioning Avalon's Canso. I'd only heard rumours about this conversion. Cheers!

FLUG REVUE 9/1991 mentioned a proposal to re-engine the Brokaw Bullet (the fastest two-seat homebuilt aircraft of its time) with a turboprop. What happened to this plan? Any results?

boxkite said:

FLUG REVUE 9/1991 mentioned a proposal to re-engine the Brokaw Bullet (the fastest two-seat homebuilt aircraft of its time) with a turboprop. What happened to this plan? Any results?

Click to expand...

Apparently, it was:

http://www.sun-n-fun.org/content/interior.asp?section=museum&body=planes/brokaw_bullet

Here's the original engine installation for comparison. It has a large-bore Lycoming (I think a 520 specifically):

Not a pure turboprop, but a conversion with a PT
(from Aviation-Week_1961-18-26)

Nice find Jens. Another shot of RCAF 109 is attached. DHC did this conversion for the first flight of the PT6A on 30 May 1961.

Also attached is a French conversion, the Beech-SFERMA PD 18.9 with twin Turboméca Bastan IVBs.

source: http://richard.ferriere.free.fr/d18/d18.htm

Mention of the PT6 testbed got me thinking of another early conversion.

DHC Otter RCAF 3682 was an experiemental STOL conversion. In its first guise, 3682 was given huge flaps, a weird quadricycle landing gear, and eventually a J85-GE-7 with twin adjustable nozzles in the rear fuselage. Later, the P&W Wasp was removed, the nose capped, and twin PT6 mounted on the wings.

source: Canadian Aircraft since 1909 (couldn't find an online image with the PT6s)

Apophenia said:

Mention of the PT6 testbed got me thinking of another early conversion.

DHC Otter RCAF 3682 was an experiemental STOL conversion. In its first guise, 3682 was given huge flaps, a weird quadricycle landing gear, and eventually a J85-GE-7 with twin adjustable nozzles in the rear fuselage. Later, the P&W Wasp was removed, the nose capped, and twin PT6 mounted on the wings.

source: Canadian Aircraft since 1909 (couldn't find an online image with the PT6s)

Click to expand...

Hmmm, makes me think if this is what eventually lead to the Twin Otter.

Anyway, back to Beech 18 conversions, Volpar came up with a slew of Beech 18 mods and conversions including tricycle landing gear, single-vert stab conversion and a twin PT6 conversion, essentially turning it into a poor man's King Air. I believe any of these mods can be purchased individually or as part of a package (as they often were).





The turbine conversions were not as popular as the other packages, most owners electing to retain the original Wasps.

Another conversion gaining popularity is the "Silver Eagle" conversion to place a Rolls Royce 250 turbine in a Cessna P210 Centurion.

http://www.airliners.net/open.file/1230460/L/

Just call me Ray said:

Hmmm, makes me think if this is what eventually lead to the Twin Otter...

Click to expand...

It was indeed. Or at least indirectly. The twin PT6 "STOL Otter" experiment was funded by the Defence Research Department (on the original image, you can make out "DRD - DHC" markings on the nose.

DHC had already realized that the PT6 made a twin-engined Otter replacement/follow-on possible. The "STOL Otter" gave them a better idea of how much of the original design could be retained. It also confirmed the desirability of a nose gear arrangement for an aircraft with reversible pitch propellers.

BTW, the J85 installation was also to be installed in the DHC-4 for tests. The ultimate plan was to mount these in the Caribou II which became the DHC-5 Buffalo (which fits this piston-to-turboprop theme, in a way).

Following on with the turboprop Caribou theme ...

The prototype Caribou II was RCAF 5303 (a CC-108-1A which had previously been the R2000-powered DHC-4 prototype c/n 1, CF-KTK-X). Conversion to prototype Caribou II with inverted T64s was completed on 22 Sept 1961. The T64 conversion flew 220 hrs as such. Later in the year it reverted to standard CC-108-1A configuration.

IIRC, Snow Aviation's SA-200 design sprang from a (1980s?) concept for a stretched and modernized DHC-4 with PT6s. Pen Turbo now offers a more straightforward DHC-4T conversion with PT6A-67Ts replacing the R2000s.

http://www.dhc4and5.org/Turbo.html
http://www.ausairpower.net/Turbo-Caribou.html

I was thinking that listings of piston-to-turboprop conversions might be useful... [Removed]

ADDED I've rationalized and updated those piston-to-turboprop list. They are on page 7.

DeHavilland/DeHavilland Canada Piston-to-Turboprop Conversions

ADDED - list rationalized and updated. Now on page 7.