Starting problems RR Gnome H1400-1 (T-58)

[TerjeM]

Looking for information about problems with starting the RR Gnome engine installed in Sea King. The problem is that the engine fails to light up when the HP cock is opened.

The problem applies to several engines, and the engines have been installed on several airframes. Atleast one of the engines has been stripped down and rebuildt without any problems has been found. They (engien shop) cannot replicate the starting problem in the engine testcell.

When the engine fails to light up several times in a row, the standard procedure is to change the igniterplug and check shim thickness. On some engines we have had success moving the igniterplug to the second position (dependent if it is a port or starboard engine).

[Miles Gustaph]

If the problem cannot be replicated in the test cell then maybe you have a problem on the airframe side and not on the engine.

[NutLoose]

What about the fuel u are using?

[BACMAN]

what about fuel tank pumps

[vib6er]

try HEIU and Lead, is fuel coming out of exhuast as a vapourised plume, if not try 'technical' tap on fuel diverter valve, go for a slightly thinner shim.

[TerjeM]

Been out off town for some days now, but to answer your questions.

Fuel used is normally F-34 (JP-8), but Jet-1A is used when re-fueling on civillian airports. The F-34 has been analyzed and found to be okay.

We did suspect a problem on the airframe side of things, but has almost eliminated this possibility because of the problem followed the engine from one airframe to another.

Fuel tank booster pumps has been checked and found okay, but we also have the problem with battery starts (without booster as they are AC).

HEIU and lead was changed early on in the trouble shooting sequence, plenty of vapourized fuel comes out of the exhaust.

Our organization is in dialog with Rolls Royce about the problem, just wondering if there was anyone out there that had experience with similar problems.

[nmm30]

Have you checked the spray pattern of the injectors?

[N1 Vibes]

Do you have a starter or g'box issue? Is your starting rotation speed consistent? Do you leave the starter on the engine when transferring it/returning it to the shop, or keep it with the airframe?

A valid question also on the fuel spray nozzles. My 1st ever hands on job as a 'green' apprentice in RR Leavsden(we wore green overalls!), was assembling and flow/spray testing the nozzles. They are very delicate and can easily get clogged with carbon debris, causing the bad spray pattern.

Good Luck,

N1 Vibes

[Tony Mabelis]

I once had a similar problem on a Gnome fitted to a Whirlwind Series 3.

The engine would not light off although there was plenty of fuel and spark.

It turned out to be the burner closest to the igniter plug was coked up and partially inop.

From memory, (40 years ago) I seem to recollect that we relocated the igniter plug to a different can, (180 degrees apart) by making a long ignition cable, and we were able to continue operating.

This would probably be frowned on these days!!

Tony

[labrinth]

Whilst many decades have passed since throwing spanners in anger at the Gnome, your engine no start problem sounds like the HP fuel cock and the NF turbine govenor linkage assy may be out of rig, if my memory is serving me correctly.

Also for memory in the early days of the Seaking there were problems with th NF govenor's (OTG) getting water into the govenor from the comp washes. Hope this may shed some light on the problem.

[tyto]

we start seaking with external A/C and if not available only then we use external DC but battery starts are only in emergency now! So far we havent had failed light ups often

[Cornish Jack]

Not SK, but on the Whirlwind10 in the 60's, we had a duff batch of igniter plugs. The only way to get a start was to remove the igniter plugs after each flight and dry them out in the ops kitchen oven for 10(?) mins and then use a carpenters thick edge pencil to coat the contacts before replacing them!! :ok:

[aeromech3]

My experience with no light off on similar RR axial/annular engines: having a confirmed fuel plume, HT ignition system checked out and no visual problem with the burner using a boroscope. To further trouble shoot, have ignored fitting shims under the ignitor and in a few cases have had the plug boss machined down by 10thou" if a satis light up then this confirmed the problem was within the chamber alignment or flow pattern.