up-nov.htm Small-Pogo Project


Small-Pogo Project


Status Updates


November, 1997

November 17, 1997

I posted a Request for Information (RFI) on the internet looking for ideas and interest. Based on responses to this RFI and information gathered from other sources the Phase I design could begin by the end of November 1977 and flight testing completed in January 1998. Phase II is less certain but could begin in early 1998 and be completed by Summer 1998.

November 26, 1997

While in Redding, California, I stopped by a model shop and talked to the proprietor. He had a six-foot model F-16 hanging from his ceiling which was powered by an OS .91 engine and Byrojet ducted fan. He told me that the power plant was rated at 4 hp and 13 lbf thrust. The plane, when first built, weighed 10 lbm. When he first flew it he did a low-level pass then pulled it up into a vertical climb. The plane accelerated nearly out of sight before he leveled it off and brought it down.

This gave me confidence that at least one power plant was commercially available to do the job. A Small-Pogo would probably weigh 6-8 lbm (no wings, smaller flight control surfaces, no wheels, no cockpit). This would give enough excess thrust for one engine to do the demonstration. The price for the power plant (engine and ducted fan) is about $550 US.

The proprietor also showed me a gyroscope used to maintain the position of the tailrotor on a helicoptor (also evidence of the possibility of vertical flight). The gyroscope runs about $130 US. One or two of these would stabilize the Small-Pogo for vertical takeoff and landing. Their output is channeled directly into the flight controls to correct for unwanted rotation.

Using this power plant, gyroscope, and other common components the Phase I vehicle could probably be built for $1200 within a month. With an experienced model builder who has some components (such as radio controls) the price could be considerably less.

November 30,1997

Going through postings on the newsgroup rec.models.rc.air I found an advertisement for kits to convert weedeater engines to model aircraft engines. The ad said that new weedeaters can be bought for as little as $60 US and the kit for $29 US.

I visited the local hardware store and looked at the weedeaters on sale. The lowest price was $79 US for a 25cc unit (but then this is off-season). The 25cc unit was very lightweight and the engine looked surprisingly like a model aircraft engine. Most of the weight was not in the engine and could be stripped off. The model I looked at had a clutch that was excess to aircraft needs.

When I returned home I looked at my own gas-powered weedeater engine. It is a Ryobi 31cc, again very light. It has a clutch that can be unbolted. The muffler and aircleaner can be replaced with lighter ones to further lighten the power plant. My weedeater already has many hours of use and still runs like new.

Today I faxed a letter to Carr Precision of Portland, OR, and asked for a catalog. With one or more of these engines it may be possible to combine Phases I and II and complete a satisfactory demonstration of the concept ahead of schedule and well under cost. This possibility will be pursued along with the original plan until one becomes obviously preferable.



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