The '37's gravel kit

[Mitch Cronin]

Sorry Zipped... feel free to hijack this thread if you like.

Kevin, interesting notions about the "chine" (thanks for recalling that term Fido) on nosewheels being for higher mounted engines... I hadn't really noticed (DC-10's didn't need 'em ) ...but that sounds probable to me...

It was one of the ex-Nordair types that told me the story of them asking Boeing to build 'em something for gravel ops... I don't remember details now, but I'm sure he thought the 37's gravel kits were first developed in response to that request... Now I'd like to know the truth also... I'll do some digging and let y'all know if I learn anything.

Cheers,

Mitch

PS... anyone know anything about Harmony?

[Fido]

....PS... anyone know anything about Harmony?

A cute little airline out in Vancouver. Lots of money behind them and run by former managers from WardAir, Canadian, PWA, there might even be an Air Canada type there.

I only mention these legacy carriers because it is quite a hoot to discover some of their pedigrees.

[AAS]

I recall DC-9's with the spray deflector (USA) behind the nose gear and some with the chined tires (EAL). Never with both.

B727's of AAL had the chined tires as well. I was lead to believe that they were spray delectors.

As for the ski on the 737 I spent many days around Nordair's fleet and understood it to be part of the gravel protection package.

You also had to jack these aircraft higher to do a gear swing.

Unpaved Strip Kit

This was an option available for the 737-200 from Feb 1969 and included:

A deflection ski on the nose gear to keep gravel off the underbelly

Smaller deflectors on the oversized main gear to prevent damage to the flaps.

Protective shields over hydraulic tubing and brake cable on the main gear strut.

Glass fibre reinforced underside of the inboard flaps.

Teflon based paint on wing and fuselage undersurfaces.

Strengthened under-fuselage aerials.

Retractable anti-collision light.

Anti vortex jets fitted to the engine nacelles. These consisted of a small forward projecting tube blowing bleed air down and forward to break up vortices which could otherwise ingest gravel.

The nose gear unit folds forward as the gear retracts seating into the faring in front of the nose wheel well

History & Development of the Boeing 737

[GreatSlave]

A bit of 737 trivia: The gravel gear requires a different towbar than non-gravel. Actually, the gravel towbar will work on non-gravel but not the other way around.

I had the misfortune of being reminded of this instantly forgotten little tidbit on about day two of my newfound skipperdom.

We missed Edmonton and went to Calgary, not one of our bases. Preparing to push in order to have another stab at Edmonton, do ya think we could find a gravel towbar? Ooops

"Dude, can ya do a powerback with this thing?", says the Air Canada leadhand.

"Sure", says the freshly annointed Cap'n, "If I feel like going back to hauling fricken' caribou antlers for a living".

A gravel bar was eventually dredged up from the Westjet scrap pile out behind the hangar and we got out of Cowtown, another lesson learned.

Kev

[Mitch Cronin]

Well ain't life fer learnin'?

Lemme throw another at ya... That normal towbar can be used on the birds with the gravel kit, but it's a bit tricky getting it in place... The difference between the two is that with a gravel kitted airplane, you can't get the normal bars front lip under the tow lug, so the towing head is mounted upside down on the "gravel bar", allowing it to get onto the lug from the top (the tow lug is the same size)... But: if you lift the nose of the non-gravel towbar high enough - about 6-8 feet as I recall - the lip will slide into place and then you can lock it on the lug for towing... and again you'll need to raise the other end of the bar way up to disconnect.

It's a bit hazardous, since even 737 towbars are heavy enough to cause injury, ...and doing that lifting trick puts the airplane in a bit of peril, should the bar slip from someone's grasp at the wrong moment.... so I wouldn't recommend it, if you can wait for the right bar.... but if you have three people, *and the need*, it can be done.

Rattler and AAS.... you're both correct of course... and thanks for that... That "ski" is indeed a gravel deflector. Though it's beefy enough, and mounted in such a way (through the center of the nosewheel axle) that I wouldn't be at all surprised if it could assist to some degree as a pretty decent ski if one were to be dropping the nose onto, or ploughing through, deep enough snow....(or mud?)?

[GreatSlave]

if you lift the nose of the non-gravel towbar high enough - about 6-8 feet

.... but if you have three people, *and the need*, it can be done. 

I was shuddering to think what must be the size of your biceps for a minute there, until I read down a bit.

Any guy who can lift a towbar over his head ...I think I'll just call him Sir.

Good morning Mitch............I..I..I mean Sir

Kev

[Mitch Cronin]

Don't pilots always call AME's "sir"? ... ....

...Mornin' Kev.

[RFL]

Hi Mitch,

This is only speculation but I believe the 737 gravel kit was developed for Alaska/Canadian Arctic operators. I do not know who was first but I believe the economies of scale etc. would suggest Wien Air/Alaska Air first followed by the Canadian operators. I observed a Wien Air 737 doing a cross-bleed start on an Alaskan gravel strip in the summer and it was a dust storm worse than Saskatchewan in the 30's.

It was a credit to Boeing that the aircraft took it all in stride.

FYI the 727-100 with the gravel kit had nosewheel "chine" tires ( to avoid gravel spray damage) plus a few other minor add-ons like hydraulic line protectors on the main gear. It was a superb gravel runway aircraft requiring only minor modifacations and operating technique. The 737 gravel kit was very capable but more complex (expensive) and required more operator finesse than the 727.

Welcome Up Here, please don your parka before leaving the aircraft!

Harmony is here for the long haul and they are a very professional operation.