GZ-20.TXT


Goodyear GZ-20 Blimp

This effort with Aircraft  and Adventure Factory was, and still is a 
continuing learning experience.  I've always admired the Goodyear
blimp and figured it was a great sightseeing platform that would be
kind of nice to just float around in and admire the scenery at a detailed 
and leisurely pace.  AAF was obviously not designed to work on 
airships of this type and size with such an odd variety of size and 
speed characteristics.  At the same time, I really didn't have all the 
detailed reference materials I'd have liked to be able to use in the 
design and construction stages.

This model of the Goodyear GZ (for Goodyear Zeppelin) 20 Blimp 
was constructed after reading an article in the November 1992 issue 
of "Private Pilot" Magazine.

There was some data provided, but a lot of the information I would 
have liked, was missing and therefore parts of the model were based 
on what I could make out of the pictures in the article as far as some 
dimensions and shapes are concerned.  The following facts were taken 
directly from the article:
                                                                                                                                                                                                                                                              
Overall Length:                                  192  feet
Overall Width:                                    50  feet
Overall Height :                                 59.5  feet
Maximum Takeoff Weight:                        12,840  lbs.
Engines:                                     210-hp  (two)
Fuel Consumption:                           15 gal per hour
Cruising Speed:                                    26 knots
Maximum Speed:                                     43 knots

The article refers to a ten hour flight which suggests that the fuel capacity 
is something in excess of 150 gallons. 

In constructing this model, some liberties had to be taken with reality:

To keep the blimp off the ground when it's moored or ready for takeoff, 
we used a mooring cable (in place of any landing gear), attached to the 
blimp's nose that was long enough to raise the blimp off the ground.  
On take-off, if the landing gear is raised,  this mooring cable will 
disappear.  For landing, the procedure is reversed and to avoid crashing 
into the ground, the mooring cable is extended by putting the gear down. 

To get the blimp to fly slowly enough, we used a SIM file from an ultralight 
aircraft that keeps its speed down in the 40 mph range.  We are not skilled 
enough to generally mess with SIM parameters so we left it as is.  Someone 
with a better grasp, of the aircraft design parameters could probably 
improve on this.  Ideally the GZ-20 would fly straight and level at 
1500 RPM at about 26 knots.  At full power, it should not exceed 
43 knots.  It can climb at an angle of 30 to 35 degrees at full power without 
stalling and There should also be a service ceiling of 10,000 feet.   
Obviously in any kind of a high wind there can  be some real problems 

Probably due to the shapes involved and the color that I wanted some 
of the parts, not everything always shows as it probably should.  
Perhaps someone can improve on the paint groups I've assigned

In the real world under actual use, I understand at takeoff, that full 
power is applied and as soon as the blimp is 15 or 20 feet in the air, 
the climb angle is increased to about 30 degrees (be careful not to 
"bend" the tail on the ground), until 1,500 feet is reached where the 
blimp is levelled off.  Most flights, I understand take place between 
1,000 and 3,000 feet.  

Landing, is another problem.  In the model, you'll have to throttle back 
and almost force it down.  Lower the mooring cable (landing gear), 
and flare out at about 30 feet and gradually lower the aircraft until the 
mooring cable touches the ground at which time brakes can be applied.

I have included an AFX file since I hope someone or more of you 
will contribute by  picking up where I left off.  It needs its flying and 
handling characteristics improved and the Goodyear "WingFoot" 
logo and the lettering added to the sides.  Of course, if anyone can 
add the moving message lights the real blimp has at night, it would 
be great.  Somehow I figure that is beyond the capabilities of AAF.

For those without AAF, I've included the necessary SIM files and 
for those with SEE, I've included an SCO file.

I'd sure appreciate any feedback or assistance I can get to finish the 
GZ-20 model up to the standard that I've seen in other models 
uploaded to the Flight Simulator Forum.

Hope you enjoy it.

Tom Carnegie
CIS:  70267,2126