Letters: 02/03

Crank Comments
The crankshaft problems experienced, first by Continental and more recently and severely by Lycoming, are a symptom of an aging and stagnant industry.

These folks, set in their ways as they are, would not consider changing. The sad fact is that the solution is well known and already in use by those building highly stressed, high reliability piston engines. The real solution to obtaining consistently high quality crankshafts in small quantities is to use billet cranks.

This is a process whereby a solid piece of rolled or forged bar stock is machined into the finished shape of the crank by a CNC machine designed specifically for that purpose. This process has a number of advantages over cast or forged cranks: several different high-strength steel alloys can be used, very short production runs do not affect the cost significantly, billet cranks are stronger than cast and tooling costs are substantially less than for forging.

The most important advantages are the higher strength margin in the finished part and that it places the responsibility for metallurgical quality with large-scale steel alloy producers-usually much better equipped and controlled-instead of in the hands of smaller casting shops. High-end automobile and boat racing engines use billet cranks extensively. Engine Components Inc., a well known provider of aircraft engine parts for rebuilders, produces new, billet cranks from 4340 (chrome molly) VAR forged steel at competitive prices.

A four-cylinder 200-HP crank sells at a dealer cost of less than $4000. Shame on the industry for not adopting modern methods of production, or better yet, simply picking up the phone and ordering quality parts for the engines we bet our lives on.

-Bill Grant
Cleveland, Ohio


Skylane Mods
I was very interested in Lionel Lavenues article on Skylane engine upgrades in the November issue of Aviation Consumer. I would also like to offer my sympathy for his 206.

At my homebase, there are no fewer than eight Saratoga II TCs and two turbo 206s with empty cowlings, gathering dust and bird detritus while they await their crankshaft transplants. I am told some may not fly again until spring. Clearly TCMs crankshaft troubles three years ago were only a sideshow compared to this debacle.

I had to chuckle at the authors description of Peterson customers as fanatical. I have been a happy 260SE/STOL owner for two-and-a-half years and 450 hours and concur with his assessment. The 260SE/STOL is a remarkable airplane and the Petersons support it really well. I think that one aspect of Skylane engine upgrades was neglected somewhat in the article: the issue of weight.

The 182 is a nose-heavy airplane even without modification and with full fuel and two front seat occupants is at or near the forward CG limit. Many Skylane drivers limit landing flap settings to 20 degrees under such conditions in order to ensure a mains-first arrival.

Even so, full-stall landings can be a manly thing, requiring two hands on the yoke. The larger engine upgrades (520 and 550) together with their three-blade propellers can involve weight increases of 30 to 40 pounds or more well forward of the CG.

Together with the increased fuel consumption, this can have the following impacts: (a) The engine/prop weight increase, combined with the additional weight of long-range fuel (88 gallons usable versus 74 gallons stock) effectively reduces the legal cabin payload to that of your average 172.

This represents a significant reduction in the aircrafts utility unless the pilot is willing to fudge departure loads. The 182R did have a 150-pound MGTOW increase compared to the 182Q and earlier models (although maximum landing weight was still 2950 pounds) so R models may not be as significantly affected. (b) The engine/prop weight increase makes the Skylane more nose-heavy than before, with consequent compromises in low-speed handling and landing characteristics.

Ballast may have to be added to the rear seats or baggage compartment to preserve the stock airplanes slow-speed flight and landing properties or possibly to avoid exceeding forward CG limits in certain circumstances.

The IO-470 (Peterson) and O-470-U upgrades (Jewell) with two-blade propellers do not involve such substantial weight increases in the engine compartment.

Thus, even though they have only 260 HP or 252 HP respectively, these conversions offer significant benefits in other areas.

-Kevin Moore
Palo Alto, California


Which Oil?
Just a short commentary on your comprehensive article on oils. I used to use Shell 15W50 in my Bonanza for years and switched to Phillips X/C once when I could not get the Shell.

My oil consumption dropped immediately. I used to add one to two quarts between 35-hour oil changes, but when I switched to Phillips, I never had to add oil between changes. The engine went well past TBO.

I purchased a Duke eight years ago and the previous owner was using Shell so I continued to do so. I was adding about four quarts to each engine between 35-hour oil changes.

After a year I decided to switch to Phillips and my oil use dropped considerably; zero to one quart between oil changes.

About a year ago, I switched to Exxon Elite and oil usage dropped even more to the point that I dont have to add oil between changes.

I know this is just one anecdotal experience, but after a few thousand hours and 20 years with both Continental and Lycoming engines, my experience has been dramatically different than what your report seems to imply.

I rank Elite number one, then Phillips with Shell coming in a distant third.

-Frank M. Singer
via e-mail

First of all, our research did not address the issue of oil consumption by brand, nor should it, in our view. Without a detailed experiment with controls over a range of engines, were not sure oil consumption means much.

Second, we dont think not using oil between changes is necessarily a good thing. As oil circulates through the engine, it picks up contaminants that filtering doesnt always remove. Further, the oil loses some of its lubricity and some make-up oil between changes helps restore this.

Last, many readers have been confused about our recommendation. We clearly stated that all of the oils tested are well-suited for intended purpose. We merely found that Shells 15W50 has the most impressive anti-wear package and this is our first pick when anti-wear properties are an important concern.


Used Avionics For Sale
As part of ongoing tests of avionics and equipment, Aviation Consumer has for sale a lot of used avionics recently removed from our aircraft. These boxes are all in working order and are yellow tagged. They also included mounting trays, where appropriate. We prefer to sell this equipment as a single lot but will entertain bids on file for individual items, as listed. The equipment and prices are as follows. Contact us by e-mail at [email protected] or telephone at 203-270-6318 to submit a bid.

Bendix/King KX-155 with glideslope – $1800
Bendix/King KLN90B GPS with IFR switching network – $800
Bendix/King KN62A DME with antenna – $1600
Bendix/King KT76A transponder – $500
Bendix/King KMA24 audio panel – $400
UPSAT/Apollo SL40 comm – $800