CAP 21

CAP 21 built by Franz Maier
Franz Maier's CAP 21 in front of his all metall home build RV4

The third or perhaps fourth CAP 21 from Franz Maier in front of his homebuilt RV-4.

Coincidentally Franz sat next to me, right at the front in the first row, for our first lecture in aircraft construction. He was (and is) as I quickly established, a real model aircraft enthusiast also. From this first meeting a life long friendship immediately developed.

Some years later, as I began to start every take off with my CAP 21 with a snap roll, Franz came along and surprised me with a one and a half snap at take off and at a much lower altitude. (Franz was always the pilot with the least nerves.) After a fair length of time I overcame my nerves to try this out and discovered one and a half is easier than one! Only once it did not work out as it should and my CAP 21's wing tip touched the ground in the knife edge position. Many hundred of takeoffs later, Franz was ready to go one stage better, on a very hot day and with a very stress laden drive. Immediately after take off, a one and a half snap roll, he landed his CAP 21 with full power on it's back ...

Conclusion: One must only continue to try, and then the CAP 21 will inevitably bight the dust. But please do not make the beginners mistake and snap roll using only the elevators and rudder. The CAP 21 definitely needs the ailerons as well, otherwise you will successfully crash the CAP 21 with the first attempt.

Franz's notes about this:

Hello Gerhard,

it is very nice what you have written! By the way my blue CAP 21 is still flying after the inverted landing. Prop bust, fin and rudder ripped off, split in fuselage. That was the shortest demonstration flight at the Plattlinger flying day.

Actually she almost crashed on her first flight, similar to her predecessor, because I used the servo cable from my same stock (trouble with cold solder joint inside the plug) luckily I noted a certain twitching with the elevators before take off. New cable from Conrad Electronic - OK; from model shop - junk!


a lasting memory of Eric Mueller, the extraordinary Pilot - full size as well as models!

Cartoon from the book Flight Unlimited of Eric Müller and Annette Carson. ISBN 0 9509252 0 9

Eric Mueller, beside Louis Pena an enthusiastic pilot for the CAP 21 Prototype (F-WZCH) writes in his book Flight Unlimited a knife edge loop is not only nonsense it is impossible.

At a flying meeting in 1988 I was able to show him the knife edge loop with a model of "his" CAP 21.

Sadly Eric has died too young and cannot experience the many impossible acrobatics we take today for granted, and try these out himself.



©2009 - Toni Clark practical scale GmbH, Zeiss Str. 10, D-32312 Luebbecke, Germany, Tel. (0049) 05741 5035 Fax. 40338

All rights reserved. No reproduction in any form without our written permission.