Lambert Monoprep (oz5376)

About this Plan

1935 Lambert Monoprep. Peanut scale model.

Quote: "1935 Lambert Monoprep, by WL Kincheloe.

The Monoprep was designed in 1935 by Al Mooney for the Lambert Aircraft Corporation of Robertson, Missouri. During one of my weekly visits to the St Louis airport in 1936 I saw a yellow and blue low-wing open two-seater with a radial engine, oversized tires and the wing number X11791 - the prototype Lambert Monoprep. In 1937 the design was modified by raising the turtledeck and adding a sliding cockpit enclosure. The name was changed to monosport, but the number X11291 remained.

Lambert started building three Monospori airframes when Knight Culver bought the design, parts and tooling and moved production to the Dart Boat Works in Ohio. The whole complicated story is covered well in John Underwood's book 'Of Monocoupes and Men' and by Jim Alaback in his write-ups of the history of the Dart GW.

I fell in love with a black and red Dart that provided my first dual flight instruction in 1938. The Dart had a personality that was forever engaging. In 1943, now a Student at Parks Air College where two Darts (of an original five) were used in the flight training operations, my association with the Dart continued. In the school library, in The Aircraft Yearbook for 1937, I found three-view that looked remarkably like the Dart but was identified as the Lambert Monosport. There, also, was a three-view of the Lambert Monoprep. I started to make a layout for a CL model of the Monosport/Dart in the summer of 1943. but my local draft board had other plans for my spare lime despite my student deferment.

Walt Mooney's Peanut model of the Dart appeared in Model Builder in 975, and later I saw a beautiful 1/4-scale RC model of the Dart at a fly-in in California, It had been done; and at both ends of scale. Then it struck me: no one had built a model of the Monoprep. During discussions with Bill Hannan it came out that he had the original ink-on-linen drawings by Harry Pack that had been used in Aero Digest and the Aircraft Yearbooks. My proof-of-scale rests on the yearbook illustrations, one of which is included with this article.

The model presented here is the result of nearly a year of spare time design and test activities. First, using the original drawings, a Peanut-sized layout was completed. Next, areas and weight estimates were calculated and the airfoil selected (Clark-Y). Next I built a proof-of-principle all-balsa profile model with a flat plate airfoil as a pleasant and inexpensive way to learn about the design's stability and performance potential without the time, expense and aggravation of build-ing the complete model. Afterthe POP model flew, the working plans for the final Peanut were drawn up and the structure detailed.

The prototype model shown here came in at a trifle over 21 grams - a bit heavy. Despite my best efforts, the model was nose heavy. Therefore, I've replaced the carved basswood propeller shown in the photographs with a Larrabee-profile bent wood prop, and have included a blade pattern on the plan, It should enhance performance and does reduce the overall weight. One important point: do not yield to the temptation to replace the hardwood wheels with balsa or some other lighter alternative! The center of gravity on the plans is shown in the highest, most rearward position lot stable flight with the angular setup shown.

The most difficult part of the work is maintaining alignment of the front frame of the fuselage, sot made a cone out of postcard stock and doped it well to provide a base to form the warning that extends from the firewall back one station. The cutting pattern for the segmented soft balsa is given on the plans along with the pattern for the cowl. Don't use CA glue on the feints of the conic patterns, as it doesn't bend well..."

Direct submission to Outerzone.

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction