Sea King Power Turbine to Gearbox Connection

[Cracker Box]

Hi, I am trying to find some info and images of the power transfer connection between the Gnome H.1400 power turbine and Sea King rotor gearbox. I need to replicate this connection, or engineer a similar alternative, to connect a H.1400 to a bespoke gearbox for a ground based application.

I have the engine and power turbine and a Sea King shaft which runs to the rotor gearbox.

(Sorry, due to lack of posts so far, I'm not allowed to post images yet).

The shaft has a Thomas flexible coupling which attaches to the power turbine output flange. Strangely, the bore of the Thomas coupling is an interference fit onto the PT's coupling which must make its fitting and removal difficult, does anyone have any experience of fitting this shaft?

I don't have a rotor gearbox but from web images I can see where and how the shafts connect. I can't, however, find any images or info on the torque tubes which run between the PT casing and the gimbal rings which are around the gearbox input shafts, I can see these must attach to the gimbal at the 3 & 9 o'clock points but if anyone can shed any light on what the tubes look like, or any other information, I'd be very grateful.

Thanks in advance,

Dave

[sycamore]

Dave, it probably depends on which engine/PT/COUPLING you have ,as the Port drive to the main gear box has an electrically driven unit in it ,called the `MAIN DRIVE`..,or it maybe in the gearbox...can`t remember...it allows the port engine to drive the PT and the electrics, hydraulics ancillaries,and rotorblade unfolding, before starting the stbd engine ,which is then used to spin-up the blades....The port engine is then set to ground-idle,it`s free-turbine is now slower than the stbd one ,and the `speed-select levers`are now positioned ,stbd forward,port SSL back,the `main-drive` can now be selected` in`(it is protected by microswitches).This now allows both turbines to share the `power`..Same system on Wessex 2 and 5.Procedure is reversed on shut down....Enjoy deciphering electrical and transmission diagrams,,,!!!!

Failing all else ,go down and find the guys who have got the SeaKing flying between Chard and Crewkerne.....

[wrench1]

Originally Posted by Cracker Box

engineer a similar alternative, to connect a H.1400 to a bespoke gearbox for a ground based application.... or any other information,

FWIW: The Gnome/T58 turbine is used in a number of high performance racing boats. I believe you would be better served to contact that side of the market instead of the aviation side. Most boat turbine applications require custom-built input shafts, engine controls and in some cases a separate reduction gearbox. This would be similar to what you are doing. The aircraft input shafts, etc. were specifically designed for more dynamic operating situations (e.g., Thomas couplings) than a fixed ground based application and may not work as you planned. Plus any "aircraft" part could be more expensive which you do not require with your install. I've never personally seen a Gnome/T58 boat install, but have been around and assisted with some other boat turbine installs like a T55, C28, PT6. There are a number of turbine boat builders out there if you search online. Here's one below. Good luck.

https://www.turbinefun.com/index.asp

[NutLoose]

Cracker, same engine on the Wessex so look at that, but your best bet is to contact one of the numerous American tractor sled pulling competitors as that is where most of the Ex RAF Gnomes ended up..

engines on the Wessex ran through a reduction combining gearbox then via a shaft to the main rotor gear box

https://www.everettaero.com/gnomebox.html

This guy may have your answer






check out the squirt

https://nyethermodynamics.com/index.html

or

http://www.schumi978.addr.com/turbin..._firstpage.htm

[NutLoose]

Also

Welcome to S & C Thermofluids Ltd Gnome Engine Test Laboratory

[Cracker Box]

Thanks sycamore. Fortunately I don't need to delve into black magic of the electrics, I just need to transfer the mechanical drive into a bespoke gearbox.

Yes, I'd forgotten about Historic Helicopters and their Sea King I will give them a try

[Cracker Box]

Thanks wrench1. I believe a lot of the boat builders tend to use the aircraft gearbox which on some Gnome (e.g. Whirlwind) and T-58 (SH-2?) installations had a compact reduction gearbox which fed into the rotor gearbox. These gearboxes give a much more boat friendly output speed than direct feed off the PT. The gearboxes connect directly to the PT without the need for a separate drive shaft and torque tube like on Sea King and Wessex. The resulting power plant is very compact and ideal for boat use.

In my application I need to drive at full PT speed into a bespoke gearbox. I will almost certainly have to use custom drive shaft and I agree, I may be able to dispense with a flexi coupling. I just want to get a better understanding of the Sea King installation.

[Cracker Box]

Hi NutLoose, I work at S&C Thermofluids!

[NutLoose]

K, Wessex is a H1200 and 1300 if I remember correctly..

Out of interest, its a long time ago since I worked on them, The Puma used a splined shaft with a Thomas Coupling flextor pack, it was six from memory (but I could be wrong) plates that clamped to the shaft in three places and also to the engine in three placed between to shaft points if that makes sense, this is a puma Turmo engine shaft.. the shaft would then slide into the gearbox and the gearbox was bolted to the engine with three long 10 mm bolts.

https://www.ebay.co.uk/itm/Puma-heli...8AAOSwL7leiaWB

..


..

[Cracker Box]

Thanks NutLoose. The basic engine is the same as in Wessex, with uprated power, but the coupling to the gearbox is very different. Our company operates several Wessex H.1200 engines driving them into the Wessex aircraft gearbox and bespoke gearboxes. The Wessex coupling is a beautiful and complex design but we have pretty much exhausted most commercially available examples of these!

In starting from scratch with the Sea King 1400s we need a simpler bespoke shaft and coupling solution than Wessex which at the same time can take the higher power. The aircraft installation does appear fairly simple and easy(ish) to replicate, especially when compared to Wessex, but I would just like to see an image of the Sea King torque tube to confirm my theory!

Nye and the other guy do great things with those boats but they use an aircraft reduction gearbox, close coupled to the power turbine, to give a relatively low speed output shaft which drive the boat or jet pump. Such a box doesn't exist for the Gnome 1400 and I need full power turbine speed into my gearbox anyway.

[NutLoose]

It might be worth having a word with these people as they are putting one back in the air

https://www.historichelicopters.com/.../Sea-King.html

[Cracker Box]

Cheers, NutLoose, I'll see if I can find any images of the Puma installation.

Nice pen pot BTW

[Cracker Box]

Yes, absolutely, they sound like handy people to get to know!

[NutLoose]

https://www.bidspotter.co.uk/en-gb/a...5-a7ac00965151

thats the box from past sale

[Cracker Box]

Yes, I've been looking at similar images to those. From them you can see where the input shafts connect and there is a gimbal ring around them which the torque tube from the power turbine connects to. It's this torque tube which is my primary interest at the moment but I can't find an image/drawing for love nor money. I have messaged Historic Helicopters to see if they can help.

Finally up to my 10 posts

[Cracker Box]

Sea King rotor gearbox, port input shaft and torque tube gimbal ring circled:



Torque tube attaches at the 3 & 9 o'clock gimbal points.

[wrench1]

Originally Posted by Cracker Box

It's this torque tube which is my primary interest at the moment but I can't find an image/drawing for love nor money.

PM John Dixson. He posts in the Rotorheads forum and is a retired Sikorsky Chief Test Pilot. He should be able to help your inquiries.
https://www.pprune.org/members/168874-johndixson

[NutLoose]

Ok this is the coupling the Puma used for the engine to gearbox, the shaft I put the pic of above was connected to the engine via a coupling similar to this

http://heliwrench.********.com/2008/...couplings.html

missing word is b logspot No gaps

also

https://ntrs.nasa.gov/archive/nasa/c...9840022225.pdf

..

[Cracker Box]

Originally Posted by wrench1

PM John Dixson. He posts in the Rotorheads forum and is a retired Sikorsky Chief Test Pilot. He should be able to help your inquiries.
https://www.pprune.org/members/168874-johndixson

Thank you for such a potentially useful contact wrench1. I have a video call later today with Historic Helicopters who are about to fit an engine to their Sea King, this may answer all of my questions, but failing that, I will definitely contact John Dixson

[Cracker Box]

Originally Posted by NutLoose

Ok this is the coupling the Puma used for the engine to gearbox, the shaft I put the pic of above was connected to the engine via a coupling similar to this

http://heliwrench.********.com/2008/...couplings.html

missing word is b logspot No gaps

also

https://ntrs.nasa.gov/archive/nasa/c...9840022225.pdf

..

Thanks for this NutLoose. The Thomas coupling is such an elegant solution to a flex drive, although I may be biased, sharing my surname with it as I do (Thomas, not Coupling, that would be weird! )

Interesting NASA paper too, it all adds to the knowledge base