Achilles 1-1/2 (oz5814)


Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - plan thumbnail

About this Plan

Achilles 1-1/2. Radio control power model. A later version of the classic Keil Kraft Achilles (oz1329) rubber model design, enlarged here 150% for Mills 1.5 power.

Update 25/11/2019: Replaced this plan with a clearer copy, thanks to RMC.

Update 25/11/2019: Added article, thanks to RMC.

Quote: "RM Plan Feature. Peter Valentine enlarges this rubber-powered Keil Kraft classic for single channel Radio Assist. Achilles 1.5.

I built my first Achilles many years ago just after the war and, with it, achieved my first fly-away from the school rugger field. There was no game in progress at the time.

With permission from the headmaster to search for the model and strict instructions to apologise for any inconvenience I may have caused. I eventually found it on top of a greenhouse in a private garden. The lady was very nice about it.

The recent purchase of an Irvine Mills .75 diesel prompted a 1.1/2 size Achilles with radio assist and this is the subject of the plan.

The flying characteristics are similar to the smaller Achilles, ie a pronounced Dutch roll and a tendency to spiral dive. I have found the ideal way to fly it is to use a fairly large rudder movement, lain either way, and control it with trim only. After launch, set the trim for a turn to the left. It should then turn to the right when the engine cuts.

On a calm day the radio is only needed to return to base ie, radio assist. The large rudder movement is sometimes required to help to turn, but is quite vicious if you go with the Dutch roll rather than against it. So be gentle, it's exiting though.

The all-up-weight is 16 ounces using one of the new mini radios, 225 nicads and vintage Solartex covering. The Mills pulls this up comfortably in a steady climb.

Construction is straightforward. The only alteration to the original, apart from the fitting of an engine and radio, is the addition of diagonal braces in the wings and tailplane to avoid warps. The wheels are available from Amerang Ltd - consult your favourite model shop.

There is no reason why Achilles shouldn't be flown free flight or, dare I suggest, as a radio controlled rubber model, though I would emphasize that I haven't tried it.

The model has also been flown with a vintage Amco .87 Mk1 and a Dart. The Mills and the Amco are slightly heavier engines than the Dart so a small amount of packing will be needed under the trailing edge of the tailplane - test glide over long grass, as they say in the best free flight circles!"

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Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - model pic


Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 003.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 004.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 005.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 006.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 007.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 008.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 009.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 010.jpg
Achilles 1-1/2 (oz5814) by Peter Valentine 1993 - pic 011.jpg

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User comments

Thank you for a treasure trove collection of free model plans. I had a KK Ajax kit when I was a kid. Never got around to building it and finally it was lost to time somewhere along. Thanks to Peter for rendering the Achilles which reminds me of the Ajax. It is built strictly to plan [more pics 004-011] other than substituting a Sunnysky Angel 2212 800kv motor for the Mills . I have also added a small elevator on one side. It hasn't flown yet but feels very light and the thrust appears way too much. I like the 11 5 prop as it reminds me of the rubber model. Thanks again to you and Peter for making it all possible. From Peshawar.
KhalidKhan - 06/04/2017
I flew the Achilles last Sunday. It flew off the drawing board as aeromodellers say. No trimming needed at all. This motor is well matched to the airframe. The elevator works too. Thanks for the plan.
KhalidKhan - 12/04/2017
Another update after some more flying. The elevator seems inadequate for a gentle landing, although I would call it acceptable for a free flight model so I wouldn't hesitate to add the second half. I am increasing battery size from 800 to 1000mah 2S as I am getting only 5 minutes air time. All in all a rewarding effort.
KhalidKhan - 25/04/2017
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Download File(s):
  • Achilles 1-1/2 (oz5814)
  • Plan File Filesize: 511KB Filename: Achilles_150_oz5814_.pdf
  • Supplement Filesize: 2083KB Filename: Achilles_150_oz5814_article.pdf
  • Supplement Filesize: 273KB Filename: Achilles_150_oz5814_previous.pdf
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