Category Archives: radial engine

Geico Skytypers’ North American SNJ-2 Team to Appear at 2017 Mid-Atlantic Air Museum WWII Weekend

GEICO Skytypers Airshow makes first appearance at popular World War II event.

The Mid-Atlantic Air Museum is pleased to announce that the GEICO Skytypers Airshow Team — a six-ship aerobatic team flying the North American SNJ-2 — will perform at the Museums 27th Annual World War II Weekend set for June 2-3-4, 2017.

The GEICO Skytypers Airshow Team will perform an 18-minute low-level flying demonstration each day of the show.

“This is an exciting first for World War II Weekend“, said Museum President Russ Strine, “as this is our first ever six-ship formation team”.

GeicoNorthAmericanSNJ2

The GEICO Skytypers Airshow Team will also “skytype” around the local area all three days of the event.

The North American SNJ-2 is a single-engine advanced trainer aircraft. Powered by a 550hp Pratt & Whitney R-1340-56 engine, the Depression-era SNJ-2 was designed to United States Navy specifications.

The Mid-Atlantic Air Museum is located at the Reading Regional Airport in Reading, Pennsylvania. For more information about this year’s event, visit the MAAM WWII Weekend.

H/T Baltimore Post Examiner.

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The History & Story of the R-985 Powered Boeing PT-17 Stearman

Climbing over the narrow, wing-root walkway and stepping on to the cushioned seat of the tandem, two-place, blue and yellow fabric-covered open-cockpit Boeing PT-17 Stearman registered N55171 in Stow, Massachusetts, I lowered myself into position with the aid of the two upper wing trailing edge hand grips and fastened the olive-green waist and shoulder harnesses.  Donning era-prerequisite goggles and helmet, I surveyed the fully duplicated instrumentation before me and prepared myself both for an aerial sightseeing fight of Massachusetts and a brief, although temporary, return to World War II primary flight training skies.

Continue reading The History & Story of the R-985 Powered Boeing PT-17 Stearman

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Tinker Celebrates 75 Years: Vultee BT-13 aircraft profile

The Vultee Aircraft Corp. BT-13 “Valiant” was a single-engine, tandem-seat trainer produced for the U.S. Army Air Corps, U.S. Navy and foreign allies prior to and during World War II. The aircraft was selected and produced as a primary and follow-on intermediary trainer due to its ruggedness, forgiving flight characteristics and stability. Most of the pilots produced in the early years of World War II conducted initial training, or Basic Training, hence the BT name, on the BT-13.

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Radial Engine Time Between Overhaul: What’s My TBO for the R-985 & R-1340?

 

Please allow me to offer some information in regard to Pratt & Whitney R-1340 & R-985 engine Time Before Overhaul intervals (TBO’s) for engines utilized on current agricultural aircraft. A letter from Pratt & Whitney (P&W) faxed to the Federal Aviation Administration (F.A.A.) dated February 13, 1990 is useful in understanding the organization’s corporate position on the radial engine.

AT-302
Ayres AT-301 Air Tractors VH-ODB and VH-ODM at Tintinara SA in May 1989
Designed by Leland P. Snow, the AT-302 designation indicates 320 gallon hopper and P&W R-1340 radial engine
From http://www.goodall.com.au/photographs/aerial-agriculture-80-1/80saerialag-1.html

“Pratt & Whitney have no company or F.A.A approved methods for providing any engineering substantiation or manual/publication revision relating to new methods or procedures which are being accomplished by operators and overhaul shops on Pratt & Whitney reciprocating engines.”

This letter establishes a, “hands off” attitude on P&W’s part concerning the Reciprocating Radial engines. Oil consumption is a major issue and is addressed in a cautionary statement constituting part of the P&W TBO considerations given in the R-1340 & R-985 overhaul manual (part number 123440).

“Oil consumption is usually one of the best indications as to whether or not the engine requires overhaul, provided the engine is performing normally and there is no indication of possible trouble or irregularities requiring more than normal line maintenance attention. A sudden increase of oil consumption or a gradual increase of oil consumption to double that which has previously been average, is usually case for overhaul.”

The engine’s primary accessories (Carburetor, Fuel pump, Magnetos, Starter, Propeller Governor, and Generator) are designed to run to engine TBO. It is our recommendation that they be overhauled at the same TSO as the engine. Ref: AC65-12A Chapter 10 Page 411 Par. Major Overhaul Our basic TBO recommendations are 1000 to 1400 hours operating time since overhaul. In order to determine this “recommended” Time Before Overhaul we have taken into consideration all forms of Agricultural utilization of the R-1340 & R-985 engine and have averaged the operating time between overhauls of engines submitted to us for overhaul over the last 25 years.

Weatherly 620A VH-WEA
Manufactuered in 1989, Weatherly 620A VH-WEA is powered by a 9-cylinder, Pratt & Whitney R-985 radial engine however the aircraft itself has a relatively low spraying capacity of 1200 litres. From http://airqueensland.blogspot.com/2015/01/r-mach-aviation_7.html

It must be noted that there is an Airworthiness Directive 68-09-01 issued to the R-985 engine. It is concerning Crankshaft flyweights and flyweight liner replacement. This AD mandates that it be accomplished at 1200 or 1600 hrs depending on propeller installation. In order to accomplish this, the engine must be disassembled to the point it is more economically feasible to overhaul than to limit to repair and replacement only. This Time Before Overhaul recommendation is made with the assumption that all manufacturers’ recommended/required periodic inspections are complied with in a timely manner throughout the life of the engine. This recommendation is not to certify or guarantee that an operator will achieve a specific number of hours operation time before an overhaul is necessary. This TBO recommendation should in no way be considered a maximum TBO limit as it is possible to safely operate an R-1340 & R-985 past 1200 or 1400 hours TSO. It is merely a RECOMMENDATION that, hopefully, will better enable an operator to develop a safe, economic engine overhaul schedule.

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12.8.2016Queenie

‘Queenie’ A Celebrated Staggerwing

Companies doing business in far-flung places use a wide variety of general aviation aircraft to visit their customers. But as far as Pat Napolitano knows, the 1941 Beechcraft Model D biplane he flies on trips representing Mid-Continent Instruments and Avionics is the only Beech Staggerwing flying today as a corporate airplane.

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Radial Engine Operation Animation (Pratt & Whitney R-985)

We give you two great videos of how the Pratt & Whitney R-985 works!

Make sure you check out our recent series on all things Radial Engine!

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Quality Control as Relates to Auto Gas Use in Radial Engines

The R-985 engine will run rather well on true 91 to 93 octane unleaded gasoline. The problem is more of a quality control issue than it is the engine’s ability or inability to effectively burn unleaded automotive fuel. It is true that the engine was designed and tested using leaded gasoline of various octane ratings.

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Radial Engine Cylinder Head Checks: Following the Service Bulletins

This is the seventh and final topic in the series about the 100 hour / annual inspection. This series focuses on maintenance performed during an effective 100 hr. inspection on R1340 and R985 engines:

  1. Oil Change with filter/screen & sump checks.
  2. Valve adjustment – Positive or compression.
  3. Ignition timing check – Spark plug servicing.
  4. Compression check – differential.
  5. Air filter and carb – heat system check.
  6. Fuel System Screens.
  7. Cylinder Head Checks.

It has been amazing to see the engine log books for both the R-985 and R-1340 engine cores coming back to us for overhaul with not one entry reflecting the visual inspections called for in Airworthiness Directive 78-08-07 (R-985-SB 1785) and AD # 99-11-02 (R-1340-SB 1787)!

The service bulletins outline an Ultrasonic inspection of the 985 cylinder heads and Florescent Penetrant inspection of the 1340 heads that must be done at each overhaul. However, there are instructions for visual inspections to be done on the cylinder heads of both engines at specific intervals! The AD Note 78-08-07 (985) stipulates visual inspection of the heads on a 150 hour interval while AD 99-11-02 (1340) states inspections must be done on a 100 hour basis!

The AD notes state the inspections must be done in accordance with the SB’s. SB 1785 which reads as follows: REASON FOR BULLETIN: (2) Provide instruction for visual inspection, at each periodic maintenance interval. The 1340 SB reads: REASON FOR BULLETIN: 3. Provide instructions for inspection of cylinder heads at periodic maintenance.

You are looking for cracks in the aluminum head that are evidenced by jet-black combustion residue deposited at the root area between two fins in the designated areas. The coloration will not be visible in areas that aren’t cracked and leaking combustion residue. It is possible for oil leaks to burn onto the cylinder cooling fins but that is usually dark brown colored and typically involves a larger portion of the head. Combustion residue is dark black and may be oily and gritty feeling. I have included a couple of scanned illustrations showing the areas of the head identified in the bulletins:

radial engine cylinder head checks

The pictures seem to indicate that the 1340 head doesn’t experience cracking around the side of the head and that the 985 doesn’t crack across the top. However, cylinders of both the R-985 and R-1340 engine can develop cracks in either location on the heads!

Some careful reviews of the requirements are in order due to the confusing wording of the AD notes vs SB’s!

R-985: The AD affecting the 985 states: “To prevent cylinder head separation from the barrel, perform the following in accordance with Pratt & Whitney Aircraft Service Bulletin No. 1785 or later FAA-approved revision.” (Paragraph) 1. “Visually inspect cylinder heads in accordance with Part B of the bulletin as follows: (Sub-paragraph) B. “Cylinders Ultrasonically inspected, inspect within 150 hours time in service after effective date of the AD, and thereafter at intervals not to exceed 150 hours time in service.”

Service Bulletin 1785 references the R-985 Wasp Jr. Engine Maintenance Manual, Part No. 118611; Periodic Inspection. That inspection table places the check of the rear of the cylinder head for cracks or evidence of exhaust gas leakage in column “B”; 100 hours! To correctly comply with the AD the 985 cylinder heads must be visually inspected on a 100 hour basis!

R-1340: The 1340 AD and Service Bulletin are no less confusing! The AD instructs the mechanic to inspect the cylinders in accordance with SB 1787 dated September 07, 1983. However, the AD states that cowled and baffled installations should have an initial inspection at 125 hours and subsequent inspections at 250 hour time in service since last inspection. All other installations (translates “Cropdusters”) are to have an initial inspection at 50 hours and subsequent inspections at 100 hours! The SB allows for cowled and baffled engines to be inspected at 500 hours and un-baffled or “cropduster” type installations at 200 hour intervals. Sadly, the AD note is the law! You get to inspect using the technique given in the respective SB and accomplish the inspection at the intervals specified in the AD! Oh well, what do you want? Good looks and money too!

By the way; if it isn’t written in the log book, it didn’t get done!

We hope you have learned a few things from this series!

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Importance of Fuel System Screens on your Radial Engine

This is the sixth topic in the series about the 100 hour / annual inspection. This series focuses on maintenance performed during an effective 100 hr. inspection on R1340 and R985 engines.

  1. Oil Change with filter/screen & sump checks.
  2. Valve adjustment – Positive or compression.
  3. Ignition timing check – Spark plug servicing.
  4. Compression check – differential. 
  5. Air filter and carb – heat system check.
  6. Fuel System Screens.
  7. Cylinder Head Checks.

Continue reading Importance of Fuel System Screens on your Radial Engine

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