General Aviation News - 21 June 2018

10 General Aviation News — 800.426.8538 June 21, 2018

If you take a moment to sit back and
look at the technology that surrounds us
all, it is really quite remarkable.
For most of us, we need look no further
than the smartphone in our pocket or the
tablet on our desk.
During SUN ’n FUN I had an oppor-
tunity to actually step into an impressive
piece of technology. I got to “fly” ALSIM
Flight Training Solutions’ AL250 flight
simulator.
Stepping into the cockpit of the AL
took me back to the 1980s when I attend-
ed the University of North Dakota and
flew countless hours in Frasca simulators.

The AL250, as I flew it, had a glass

cockpit, a twin engine throttle quadrant,

and an immersive 250° wrap-around

view. But it also has the ability to be a

steam gauge paneled, single engine piston

aircraft in mere moments.

My short flight — from/to KOSH —

demonstrated you don’t need motion to

feel movement. Thanks to three high-res-

olution projectors operating at 60 frames

per second, my eyes and brain did the rest.

The sensation was so realistic I couldn’t

help but think, “Are you sure we aren’t

moving?”

The AL250, which is designed as a ge-

neric flight simulator, can be configured

as a primary or high performance single

or light twin.

ALSIM was founded in France in 1994,

which is just after I graduated from UND.

While 1994 was long before the current

wave of technological innovation, it is ob-

vious to me ALSIM has taken full advan-

tage of what is available. While the AL

is neither a tablet nor a smartphone, it is

part of the technological revolution that

permeates nearly all parts of aviation.

I hope you’ll join me in taking advan-

tage of all that technology has to offer,

while making certain it stays in its proper

place: That of servant, not master.

UNLEADED AVGAS
Banning lead in aviation gasoline as a
source of environmental pollution that is
dangerous to humans is just another case
of the “Eco-Nazis” run amok.
Can anyone tell me the name of one
person — just one — whose death can
be directly traced to lead deposited into
the environment by the exhaust from a
reciprocating engine in a general aviation
aircraft?
Didn’t think so.
JERE CALEF
via email

ERRONEOUS THINKING
I have great respect for Ben Visser’s
experience and knowledge of aviation
fuels and lubricants, but I find that he is
erroneous in some of his comments in his
column, “CYA, the FAA and the new un-
leaded avgas,” in the Feb. 22 issue.
First, to the best of my knowledge,
100LL was “approved” by the FAA to be
used as a replacement for aviation grade
80/87 fuels sometime in the early 1970s
as a result of the 80/87 becoming unavail-
able, probably due to low volume since
the airlines had converted from piston en-
gines to jet engines needing kerosene (jet
fuel), but the approval was made without
any testing of the various engines for
long-term use of the 100LL, which con-
tained four times the lead of 80/87.

There were and are 80 octane aircraft

piston engines that simply will not toler-

ate long-term use of 100LL without hav-

ing serious exhaust valve problems as

well as spark plug fouling problems.

In his column he chose a bad example,

in my opinion, of a Franklin engine that

wants to fly on the future 100UL.

Let me tell Mr. Visser a few things

about Franklin 150/165 engines used in

Stinsons and some other aircraft.

First, refer to page 13 of the General

Service Manual for Stinson Model 108

Series Airplanes under the heading RE-

FUELING, Paragraph 21: “The airplane

is equipped with two fuel tanks, one in

each wing. The tanks in the models 108,

-1 and -2 hold 20 gallons of fuel each. Af-

ter refilling these tanks replace the filler

cap with the vent tube pointing forward.

Aviation Grade 80, unleaded, fuel is rec-

ommended.”

Let me relate a little of my experience

of flying behind and maintaining Franklin

engines in Stinsons over the past 50 years.

My Stinson was equipped with a Frank-

lin 6A4-150-B3. In the early 1970s when

100LL first came out, I started to use

100LL. Within less than 300 hours I ex-

perienced a burned exhaust valve!

After cylinder removal and replacing

the valve, in a 100 hours or so, another

exhaust valve burned. This happened sev-

eral times over the next few years.

At some point in the late 1970s or early

1980s I obtained the Petersen STC for

use of unleaded auto fuel as long as no

ethanol was present. I did not have engine

problems after switching to auto fuel.

Then, around 1983, I did a major over-

haul on my Franklin. I broke it in on

unleaded auto fuel and over the next 29

years I flew that engine for 1,200 hours

(TBO) using unleaded auto fuel 100%

except when on long cross-country flights

where the only available fuel was 100LL.

When forced to use 100LL I added TCP.

Over those 29 years I had three partial

engine failures while on long trips due to

broken rocker arms due to stuck exhaust

valves due to lead build-up on the valve

stems.

In all three instances, I was able to get

to a hard surface runway and in all three

instances I was able to replace the broken

rocker arm on the spot with spares that I

carried with me on long trips.

But, with 90% of the 1,200 hours op-

eration, no exhaust valves burned!

The other thing about these Franklin

engines that was much different from the

Continentals and Lycomings: They were

originally equipped with stellite or similar

hardened valve seats and at no time have I

ever noticed any signs of valve seat reces-

sion due to lack of lead in fuels.

The problem with highly leaded fuels

in these low compression air-cooled en-

gines is that combustion temperatures and

pressures are not high enough to get the

lead out of the engine during operation

and it builds up on the valves and ther-

mally insulates the valve from the only

cooling medium, the valve seat conduct-

ing heat to the cylinder head cooling fins

and therefore allows the valve to get over-

heated and burn.

The bottom line is that the Franklin

6A4-150-B3 simply will not tolerate

long-term use of 100LL, which should

never have been approved for use in that

engine from a safety standpoint.

Unfortunately, Eaton refuses to manu-

facture replacement exhaust valves for

these fine Franklin engines (liability ex-

cuse?) which is what the OEM used.

The Franklin 6A4-165-B3 engine uses

a different exhaust valve, has a higher

lift cam, operates at higher rpms, and

has much stronger valve springs, allow-

ing higher seating pressures and therefore

better heat conduction even with the high

lead content of 100LL.

It can also be legally fitted with the

Franklin helicopter engine sodium cooled

valves with rotator that helps immensely.

In 2012, I replaced my 6A4-150-B

Franklin with a Lycoming O-360-A1D

with the Univair STC. This Lycoming en-

gine was originally certified on aviation

Touch & Go

Ben Sclair

LETTERS | See Page 11

LETTERS TO THE EDITOR

Have something to say?

Send comments to [email protected] or fax 858-712-1960.

Include your full name, address and telephone number (for verification purposed

only). Please limit comments to 250 words or less.

Are you sure we aren’t moving?

Ben Sclair is Publisher. He can be reached
at [email protected].

Photo by ALSIM Flight Training Solutions

Ben Sclair in the left seat of the ALSIM AL250 at SUN ’n FUN 2018.