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Chase YC-122C Aircraft, Stroukoff Avitruc Assault Aircraft Photos and Information

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Revised 1/7/13 and will be expanded a lot this year



The YC-122C, the final variant of the Chase assault aircraft!

Our family owned two YC-122C's from 1956 to 1966 and used them for spraying and fire fighting. They were an incredible performer and there was something about them that lent itself to intrigue. Maybe that's why so many ended life in the way they did. Of the six that were sold for civilian use, they are in a lake in Alaska; on a sand bar in the middle of a river in Guyana; in the ocean in the Bermuda Triangle, and another crashed in Alaska. More info when we get to the individual aircraft!

BROCHURE - This is an incredible piece with lots of detail. Note that they had the tall tail, different from the YC-122A but like the one YC-122B. The Chase was quite a performer, as you can see from the brochure.


Nine YC-122C's were built. Click on the USAF serial number below for more details on each aircraft.

  49-2879, CY-879, Carolina Aircraft N122E, have FAA file on paper, photos
  49-2880, CY-880, Carolina Aircraft N122M, have FAA file on paper, photos
  49-2881, 49-2881, CY-881, no info
  49-2882, CY-882, Stoltzfus N122R, have FAA file on CD, many photos
  49-2883, CY-883, became Hiller X-18, have articles, photos, stock and as X-18
  49-2884, CY-884, Stoltzfus N122S, have FAA file on paper, many photos
  49-2885, CY-885, Johnson N68595, have FAA file on paper
  49-2886, CY-886, Johnson N5904V, have FAA file on CD
  49-2887, CY-887, no info, have promo photos


GOVERNMENT SURPLUS - Even the sale of these aircraft by the USAF was filled with intrigue. As I recall, the Chases were offered once, but there was some hanky panky by someone who wanted them for the (then hard to find and very valuable) 1425-hp R1820's for Lockheed Lodestar conversions. The bids were thrown out and they started over. I don't have it all sorted out but here's what I know.

Invitation For Bid, IFB 02-601-s-56-5, is referenced in the Aug. 17, 1956 summary of bids. (I don't know what the other aircraft were, but they were not Chases.) Father bid on seven items so it appears that there were seven Chases, probably including the one "B", 48-1370, later N122A, but I'm not sure. Father had made a lot of money spraying the Mediterranean Fruit Fly in Florida that year and must have been feeling pretty frisky when he submitted his combined bid of $115,000 (in 1956 dollars) for seven aircraft! Then there is the Nov. 26, 1956 award of two aircraft, which became our N122R and N122S.

Finally, is the Jan. 13, 1957 letter from Lynn Roberts to the government, and he references IFB 04-607-s-57-9. There was controversy regarding how combination, or all-or-none type bids were interpreted. I value his letter for the kind (and true) things he says about Father more than the technical details of the government sale!


FAA - The YC-122C's were operated under CAA (now FAA) Type Certificate AR-25, which was issued to Roberts Aircraft, of Boise, Idaho. Note the absence of detail there, as the basis for their operation was the military manuals and CAA Operations Limitations (which varied a bit from one aircraft to another based on which CAA office issued them). Some FAA documents will show the manufacturer as Roberts, others as Chase.

The Chases qualified for such certification on the basis of their satisfactory military operating history. Their main rival in the assault aircraft competition was the tri-motor Northrop YC-125 Pioneer, which didn't qualify for civilian certification because they didn't have enough military service. They were also an outstanding performer but were not used in the U.S. under civilian registration.

LANDING GEAR - Contrary to some images, including the brochure cover (49-2880, later N122M), the YC-122C had a fixed nose gear. It had dual tires of the same size as Twin Beech or Twin Otter mains. The main gear was also fixed, with the same size tires as the DC-3/C-47. The "A" and "B" had retractable nose gears and maybe the Chase Aircraft marketing department thought the pilots forgot to retract the gear in the photos of the "C"! I have an original 8x10 of that shot and it is sans nose gear, with very nice touchup work!


ENGINES - The YC-122C's were built with 1425-hp Wright R1820-101 engine (single row), but all civilian aircraft were converted to the 1900-hp Wright R2600-20 engine (twin row) as used on the Grumman TBM. Some had the 1700-hp Wright R2600-29A or -35 (North American B-25) engines installed later, after they were limited to 1700-hp because of the propeller issue. (see below.) The -20’s were becoming more valuable because TBMs were being used on spraying and firefighting, and we had a couple hundred overhauled -29A or -35’s that we had bought for less than $500 each, so we installed them when replacements were needed.

Hamilton Aircraft worked with a DER (Designated Engineering Representative) from Chase Aircraft and got the conversion approved. Gordon B. Hamilton was a personal friend of Father's.

PROPELLERS - We had a propeller issue with the Chases. When Hamilton Aircraft in Tucson, AZ converted them from 1820’s to 2600’s, they installed TBM props, i.e. 23E50 with (wide) 6501A-0 or 6507A-0 blades. The problem was that these were not approved for use on a multi-engine aircraft, i.e. where the blades would flex each time they passed the fuselage.

Our aircraft were grounded from late 1958 until Feb. 1960. Father finally figured out that we could use the 23E50 prop with 6359A-18 (toothpick) blade as used on the B-25, but it required that we limit the engines to 1700-HP, the same as the B-25’s -29A and -35 engines.

All military photos, and my early shots of our N122S will show the Curtiss Electric prop (long prop dome). The earlier shots of aircraft with the R2600's will show the wide "paddle" blade and later ones the narrow, or "toothpick" blade. I will point that out in my section on our N122R and N122S.

Lots, LOTS more to follow including ads, press releases and more!




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