A few questions about the "Goose"

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Re: A few questions about the "Goose"

Postby OGJ » Sat Sep 22, 2018 11:18 pm

My attempt to answer my questions that I asked at the beginning of this thread.

( 1 ) From checking around on the internet I understand the first (approximately) 12 aircraft were classified as model G-21, which had according to Grumman's first add, about what they called The Grumman "G-21" Amphibian, which appeared in the Aero Digest, Jan. to June, 1937 edition on page 68, of March, it states: Gross weight: 7500 lbs., Engines: Pratt & Whitney Wasp Junior R-985, rated 400 h.p.

The G-21A came with an increase of 500 lbs. giving it a gross weight of 8000 lbs., 50 more horsepower for a total of 450 hp per engine. I have also seen a lengthened hull and minor hull design change, listed with the G-21A, did it come with anything else, compared to the G-21?


According to Fred Knight's "The Grumman Amphibians", the rear or aft of the step of the hull was increased in length by 4½ in. or (11.43 cm. for the metric people) to reduce spray control on water landings & take-offs. This was first accomplished by fitting wooden blocks to the step and on June 3, 1937's test flight, solved the problem. The first goose c/n 1001 was brought back in and the step on the hull was re-modelled accordingly. All subsequent G-21's had the remodelled step incorporated during production.

So as I read it, there was no difference between the G-21 and the G-21A when it comes to the lengthened hull, as both had the same hull/step design.

The G-21A's had a redesigned tail wheel, compared to the G-21, but it is not stated what the change was.

As to the G-21A, Fred Knight further states: "With up-rated 450hp Wasp Junior SB-2 engines and a gross weight increased from 7,500 to 8,000 lbs." Earlier in his book he stated: "Among the safety factors highlighted in early advertising for the Goose was the use of "proven & dependable" Pratt & Whitney engines of 400hp each. This rating was based on the use of 80 octane fuel. Some literature quoted a 450hp rating but this only referred to a take-off rating when 87 octane was used. He also states the engines were Wasp Junior SB engines". These would have been on the G-21.

A little confused here, were they to use 87 octane fuel to get the 450hp rating or was there an actual engine modification to get the extra 50hp, such as timing/spark, carburetor, increase RPM, etc.?, he does not state that.

He states the G-21 had "Wasp Junior SB engines" and the G-21A had "Wasp Junior SB-2 engines" I suppose Pratt & Whitney through the Federal Aviation Agency, could have upgraded the rating of their engine for the 50hp. increase or maybe the SB engines only produced 400hp and the SB-2 engines produced 450hp.

Now after typing that, I dug around in my Grumman files (they need to be put into some type of order) and found a .pdf file entitled "G-21A Erection & Maintenance Manual", dated February 1, 1938. In this file it states:
Engine Data
Engines (2) Wasp Jr. "S.B." Pratt & Whitney
Type Radial Air Cooled - 9 Cylinders
Horsepower & RPM Take-Off 450 at 2300 with 87 Octane
400 at 2200 with 80 Octane
Maximum Horsepower for Continuous 400 at 2200 (Up to 5000 ft. Operation - Critical Altitude)
Cruising Horsepower (Recommended) 300 at 2000 rpm

So I'm really no farther ahead on this one as to the difference between the 400hp & the 450hp rating of the engines except for the extra 100 RPM and the difference between 80 & 87 octane fuel.

I also understand that a number of the first 12 aircraft were upgraded to G-21A specs. before leaving the factory and some were returned to the factory for the upgrade. Does anyone know the numbers of the 12 that were upgraded and the number that were not upgraded?


Well Fred Knight states, "The twelfth and last "Grey Goose" came off the line as a G-21A Goose". These improvements were approved on Feb. 5, 1938, also under ATC 654, and during 1938, all 11 G-21's, with maybe the exception of c/ns 1009, 1010 and 1011 which had been exported , were modified to G-21A standard."

Ok, he said "maybe the exception of c/ns 1009, 1010 and 1011" but then in Appendix 1, page 310 he states: "c/n 1011 - Built as a G-21 and ordered August 1937 by John Shaffer Phipps New York, N.Y., with BoS Nov. 26, 1937. Regd. to Phipps as NC1294 Nov. 29, 1937 and uprated to G-21A standard in 1938" Since c/n 1011 was not exported but c/n 1008 was, I think Fred Knight might have made a mistake by saying "c/ns 1009, 1010 and 1011" and it should have read c/ns 1008, 1009 and 1010. Further more he states c/n 1008 was delivered to Asiatic Petroleum, New York, on October 25, 1937, crated and shipped to Sydney, Australia, arriving there on December 26, 1937. He also states that Goose c/n 1012 was the first converted G-21A at the factory and it went out on December 9, 1937.

So to answer my own question, it looks like only three were not uprated to the G-21A specifications, c/ns 1008, 1009 & 1010. BANG - the gavel has fallen…….case closed.

The question of: "What is the difference between a Mark I and Mark II ?", will have to wait for awhile as I try and sort out some of this new info, hey at least it gives me something to do.

Dennis
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Re: A few questions about the "Goose"

Postby Kiwithrottlejockey » Sun Sep 23, 2018 2:14 am

That book is not the type you read from cover-to-cover. I read the individual chapters about the various aircraft (Goose, Widgeon and Mallard), but most of the book is like a huge cross-referenced library of facts & figures about individual airframes, cross-referenced with registration, owners & operators; which is there to be refered to when looking for information about a particular airframe, or about fleets operated by a particular operator. Attempting to read the entire book page-by-page from cover-to-cover would be a rather mind-numbing exercise. However, I'm constantly referring to my copy of the book, looking up information on various airframes. Like all Air Britain books, it is a real bible of facts & figures & info.
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Re: A few questions about the "Goose"

Postby MrWidgeon » Sun Sep 23, 2018 2:18 am

Sorry, I haven't been paying attention to this page lately.

NOTE: I was a consultant in the preparation of the book in mention.
For what it is, Fred Knight's book IS the be all, end all for the Goose, Widgeon and Mallard, BUT it does have some errors (what book doesn't).
It's a rare day when I don't use at least once (usually more) it for sorting out some information for someone (my copy looks like it more like 40 years old vs 4, the covers are worn out, but the binding is still good)

Regarding the difference in HP, I suspect it's in the fuel used, as a comparison point the P&W R-2800-CB17 radial engine develops 2500 hp using 115/145 octane Avgas, but using 100 LL (the current standard Avgas) the same engine is now an R-2800-CB16 developing only 2400 hp.
100 octane Avgas wasn't fully developed until early in WW 2, so the standard would have been either 80 or 87 octane with 100 octane being developed for use on high performance engines used on fighters, there were probably also differences in dash numbers between the earlier engine on the G-21 and the ones used on the G-21A.

As for the difference between the Goose 1 (no such thing, it was just the Goose) and Goose II, the Goose series were the first 13 G-21As purchased from the US, mostly off the civilian market.
The Goose II airplanes were all former JRF-5 series airplanes purchased off U.S. Navy contracts.
All of the original Goose airframes were given RCAF serial numbers in 700 range and all of the Goose II airframes were in the 300 range plus 2 FP serials used by the British Air Commission.
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Re: A few questions about the "Goose"

Postby OGJ » Sun Sep 23, 2018 11:22 pm

MrWidgeon said:

"Regarding the difference in HP, I suspect it's in the fuel used, there were probably also differences in dash numbers between the earlier engine on the G-21 and the ones used on the G-21A."

This from: FEDERAL AVIATION AGENCY TYPE CERTIFICATE DATA SHEET NO. E-123 Revision 14
PRATT & WHITNEY Wasp Jr. SB, SB-2, SB-3

Model Wasp Jr. SB, -2, -3
Rating
Max. cont., hp., r.p.m., in. Hg., at: Critical alt. (ft.) 400 - 2200 - 33.5 - 5000
Sea level pressure alt. (ft) 400 - 2200 - 34.5 - S.L.
Takeoff (five minutes), hp., r.p.m., in. Hg. 400 - 2200 - 34.5
450 - 2300 - 36.5
Fuel (minimum grade aviation gasoline) Grade 80/87
Weight (dry), lb. 640, 653, 668
NOTE 3. When Grade 80/87 is not used, Aviation Grade 80 is suitable for a maximum of 400 hp. and Grade 91 should be used when higher power is attained.

Wasp Junior SB engine in a G-21 - 400hp
Wasp Junior SB-2 engine in a G21A - 450hp
Ok, we will probably never know exactly what the difference was, wether it was fuel, rpm or a combo of the two or something else. It could have been the SB engine, on 87 octane was rated only to turn 2200rpm and the SB-2 was rated for 2300rpm.
Interesting to see the dry weights listed, I take it for granted the SB was 640 lbs, SB-2 was 653 lbs & the SB-3 was 668 lbs.

"As for the difference between the Goose 1 (no such thing, it was just the Goose) and Goose II, the Goose series were the first 13 G-21As purchased from the US, mostly off the civilian market. The Goose II airplanes were all former JRF-5 series airplanes purchased off U.S. Navy contracts."

In "The Book", Chapter 7, Military Operators, page 119, top left paragraph.

Fred states: "After some consideration the Canadians, presumably in discussion with the British, called all their new aircraft Mk II (Goose II) and retrospectively identified all their earlier aircraft (powered by the Wasp Junior SB engines) as Mk I (Goose I)."

My question was "What is the difference between a Mark I and Mark II ?", irrelevant if there was a Goose or Goose I or Goose II. In "The Book" it seems all RCAF Mk I's were listed as Goose and all RCAF Goose II's were Mk II's but the type of Mk numbers are not listed. The only difference I can find is the Goose or Mk I's had Wasp Junior SB-2 engines and the Goose II or Mk II's had the same basic engine but was designated as a military R-985-AN-6 engine with the exception of four aircraft, c/ns B-39, B-40, B-45 & B-50, which had R-985-AN-6B engines.

There were 31 Gooses listed in the RCAF.
13 - Mk I's with Wasp Junior SB-2 engines
14 - Mk II's with R-985-AN-6 engines
4 - Mk II's with R-985-AN-6B engines

Am I correct in assuming that?

"All of the original Goose airframes were given RCAF serial numbers in 700 range and all of the Goose II airframes were in the 300 range plus 2 FP serials used by the British Air Commission."

I don't want to be too picky but only 3 of the original RCAF Gooses had a 700 range number, 796, 797 & 798 the other 10 aircraft were in the 900's, ranging from 917 to 944 for a total of 13 aircraft.

The 16 Goose II's or Mk II's did run in the 300 range numbers, from 382 to 397. Plus 2 FP serials used by the British Air Commission and were operated by the RCAF. FP471 & FP473.

Most of my former RCAF Goose info came from http://www.rwrwalker.ca/ Canadian Military Aircraft Serial Numbers, ran by R. W. "Bill" Walker. Richard William "Bill" Walker passed away on October 17, 2016, London, Ontario and his site has been taken over by: "Canadian Warplane Heritage Museum".

Dennis
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Re: A few questions about the "Goose"

Postby MrWidgeon » Mon Sep 24, 2018 5:10 am

Ahh nuts, I had an error and when I corrected it I deleted the 900 range accidentally.
And it looks like I failed my Evelyn Wood speed reading class, I totally missed the Goose I reference (my bad). :lol:
My strong suite is the Widgeon which I've had an interest in for over 60 years, the Goose is a recent addition in just the last couple years.

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Re: A few questions about the "Goose"

Postby dogsbody » Mon Sep 24, 2018 4:49 pm

MrWidgeon wrote:Ahh nuts, I had an error and when I corrected it I deleted the 900 range accidentally.
And it looks like I failed my Evelyn Wood speed reading class, I totally missed the Goose I reference (my bad). :lol:
My strong suite is the Widgeon which I've had an interest in for over 60 years, the Goose is a recent addition in just the last couple years.

Bill


Wasn't that the Evelyn Woodhead Sped Riddin' Course?

https://youtu.be/HrwDzuUtQKY




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