Wing Loading GN-1 Aircamper

The wing loading is another useful aircraft design ratio and is the gross weight of the aircraft divided by the wing area.

For a GN-1 Aircamper having a gross weight (Wo) of 1100 lbs and a wing area (S) of 145 square feet, the wing loading (W/S) = 1100 / 145 = 7.59 lb per square foot (psf).

Power Loading GN-1 Aircamper

The power loading is a useful aircraft design ratio and is simply the ratio of the gross weight of the aircraft (Wo) to the aircraft's available engine power (hp).

Power loadings for home built aircraft typically range from 10 to 15 lb per horsepower.

Using a TMX O-200 engine, the power loading for my GN-1 Aircamper will be approximately 1100 / 100 = 11 lb/hp.

Comparatively, the power loading for a KR-2 (shown below) is 11.2 lb/hp. Although I'm sure my Aircamper will be nowhere near as fast !

An Engine for my GN-1 Aircamper

I've decided on an engine for my GN-1 Aircamper. The engine I've selected is a TMX O-200 experimental engine manufactured by Teledyne Mattituck Services Inc.

Here's the link to their site... http://www.mattituck.com/

Whilst it's not the cheapest option on the market I like the reduced risk offered by a proven powerplant constructed to a certified ISO 9001 quality system.

The TMX O-200 engine drives a fixed pitch propeller and delivers 100 HP. The engine weighs approximately 215 lbs. Overall dimensions are 23"x 31"x 28".

Aspect Ratio GN-1 Aircamper

Let's have a look at the aspect ratio of the GN-1 Aircamper wing.

First a definition... "Aspect ratio is defined as the ratio of the span squared to the wing area, which reduces to the ratio of the span to the chord in the case of a rectangular wing."

The GN-1 Aircamper has a rectangular wing with a span of 29 ' (348") and a cord of 60". Giving a wing area (S) of 29 x 5 = 145 ft^2.

The aspect ratio (A) of the GN-1 Aircamper wing is therefore 348/60 = 5.8.

This is a relatively lower aspect ratio compared to the wing of a Cessna 150 (pictured right) which has an aspect ratio of approximately 6.95.

Here's some more info on the effect of the wing aspect ratio...

(1) As the angle of attack is increased, the corresponding lift that can be produced by a wing progressively increases as the aspect ratio is increased.

(2) Marked reductions in drag occur at higher lift coefficients as the aspect ratio is increased.

(3) A lower-aspect-ratio wing will stall at a higher angle of attack than a higher-aspect-ratio-wing.

Design Specifications GN-1 Aircamper

Design specifications for the GN-1 Aircamper are provided below (as stated on Plans Set No. 3582AC).

Span 29' (8839 mm)

Chord 60" (1524 mm)

Length 18' 1" (5512 mm)

Height 6' 8" (2032 mm)

Engine Power 65 - 85 hp

Maximum Speed 115 mph (99.9 knots)

Cruise Speed 87 mph (75.6 knots)

Stall 25 mph (21.7 knots)

Take Off Run 300' (91.44 m)

Rate of Climb 500 fpm

Gross Weight 1100 lbs (499 kg)

History of the GN-1 Aircamper

Reproduced below is an excellent account of the origins of the GN-1 Aircamper.

"Early in 1958, John W. Grega, EAA 3808, embarked on the Pietenpol Project, the object of which was to modernize the excellent 1933 Model A Ford powered version, to a Continental A-65 powered two-seat "fun plane" with good small field capabilities, using modern straight forward construction methods.

With engineering know-how available to him from his then EAA Chapter 5, located at the old Welcome Airport in Northfield Centre Township in Ohio, John Grega enlisted the aid of a fellow member to run a preliminary weight and balance on the 65 hp version of the Pietenpol Aircamper.

Armed with this data, John Grega, an experienced woodworker, proceeded to design a new fuselage structure employing Piper J-3 motor mount, landing gear, control assembly, and tail wheel assembly. Using a GN modified clip wing off a J-3 Cub, for which the original fuselage designed was intended. Along with the use of a J-3 wing, an improved and modernized version of the original Pietenpol Aircamper wing was initiated, lending versatility to the design. The original airfoil was redesigned with a more rounded leading edge for better stall characteristics, the truss was improved for more strength, and spars were relocated for greater depth and in keeping with modern designed parameters. Construction of the GN-1 prototype was immediately started after the original drawings were completed. This was to the be the J-3 wing version. John Grega finished and was flying his GN-1 prototype, N4705G, in 1963.

Selling plans on the GN-1 Aircamper was the furthest thing from John Grega's mind, until a small article appeared in the June 1960 issue of Sport Aviation, regarding the fact that the GN-1 was under construction. From that time on, the amount of mail received by John Grega was overwhelming, all letters expressing the desire to purchase plans for the GN-1, if and when available. Most requested parts were drawn up and sent out so construction could start. All sketches, doodles, and bits and pieces of construction were correlated into a set of drawings, first pencil tracings, and as construction problems arose, they were resolved and incorporated into a finished set of drawings. The finished set being officially copyrighted in 1992, by John W. Grega."

Source: http://www.pilotfriend.com/experimental/acft3/55.htm

Every Journey has a Beginning

Ever since I was a young lad I have wanted to fly. And few years ago a burning desire took hold to build my own aircraft.

Hence, this project was born... To study the design and construct a GN-1 Aircamper.

I have created this blog to share my experiences.

Friends are very welcome and both questions and criticisms will be warmly received.