Centurion Two (oz7939)

About this Plan

Centurion Two. Radio control sailplane. 100in wingspan, 618 sq in wing area. This kit used a prefabricated plastic fuselage, so no formers are shown for the fuse.

For the Centurion Two as it appeared in 1974 RCM, see Centurion II (oz10952). This here is the design as it was kitted by Soarcraft.

Quote: "While we have previously stated that the Centurion II was basically conceived as an R/C Sailplane Trainer, the prototypes which have been used for testing purposes, have racked up many impressive contest trophies. It is recommended that if the Centurion II is to be used as a trainer the control surface responses he minimized to prevent over-reaction.

The light weight characteristics of the plastic used definitely fall within the weight specifications of the Centurion I even though the wing has been extended to 100 in. The Centurion II excells as a contest ship due to its light wing loading thus making it very responsive to light thermal lift. Its ability to turn on a dime and give four cents change makes it excellent for centering in small thermals. Pre-production tests of the Centurion II on slopes with winds of up to 30 mph have demonstrated its exceptional penetration and broad forward speed envelope. It can be flown quite slowly to catch ihermals and quite rapidly when it is necessary to cover distance to find new thermal activity.

CONSTRUCTION: In accordance with the design basis on the R/C Sailplane Trainer, the construction of the wing surfaces has been greatly simplified to provide for minimum building time and effort. It has been found that without really extending ones self, the modeler can sacrifice one weekend of flying and completely construct the Centurion II and therefore gain many hours and weekends of future flying pleasure.

The construction of Ihe Centurion II is simple and straightforward. Begin with the fuselage and then continue construction of the tail section and complete with the wing construction..."

Direct submission to Outerzone.

Update 06/03/2019: Added manual, thanks to JoeHayes.

Quote: "Hey Steve, I was bumbling around the site and came across the Centurion II and saw that it was missing the instructions. Well I just happen to have them and the 1974 RCM article also. Since you and the folks that have been so kind to share so much I figured I would join in, so attached are the two items mentioned . . . ;>). Joe"

Note the Soarcraft manual contains much text that does not appear in the RCM article, including notes on trimming, flying, thermalling and landing the model.

Update 24/03/2020: Added kit review from RCM September 1977, thanks to RFJ.

Update 27/3/2025: Replaced this plan with a clearer copy, scanned at 300 dpi from fullsize, thanks to MichaelMcIntyre. Also added annotated plan showing mods.

Quote: "Hello, I have a new in the box Centurion Two that has the plans in fairly good shape. But I printed out the one from your site and the scan was not that good. So, I carefully scanned my plans at the 'best' resolution.

I also have attached a copy of the older plan with my notes on - where I did some changes on the design as I learned from each one that crashed of some poor design flaws in it.

In Christmas of 1974, I was given my 1st Centurion II kit for a Christmas present ( I was 15 years old at the time). I went through three of them (crashing two of them but still have a flyable #3). Still have one new in the box yet (#4). I did some slight improvements on the problems that I had with each of them on the design problems.

Living in the Midwest, the plastic fuse didn't like the cold and was brittle. When the fuse cracks or gets broken, you glue the fuse back together with Testors model glue for plastic kits like the cars and boats and other plastic model kits. And you let it dry for a day or so.

1st problem was the wing would flex a lot on tow (winch). Folded a wing on a gusty day on the towline (there goes #1). Built #2 -- changed one wing wire to 3/16 from 1/8 and moved it to where it was inside the main spar and added more plywood shear webbing. It went up on the tow much better with the slightly bigger wing wire inside the main spar (less wing bending.)

Then the next problem. I caught a thermal down wind. I decided to bring it back, so I pushed the elevator stick forward a little to try to bring it back. Next thing it was in a steep dive, the wings started to flutter, then one wing broke off! (there went #2).

We all looked over the wreckage of #2 and one club member told me that the stab was built wrong. I told him that I built it like the pans had it and used the parts in the kit? The guy told me that I had a lifting stab, and it was not symmetrical and that is why it went into a dive. As the plane went faster, the stab started to make/create more lift and forced the tail to lift more.

So, onto building Centurion II number 3. Now, after the previous crashes (learning experiences) I incorporated all of the modifications into #3 which is the best one of the Centurion II's that I have and still have to this day.

Attached I have scanned the plans of the mods I have done on my #3 Centurion II [see supplement 'annotated' file] for anyone who wants a better plane. Thank you, Michael McIntyre"

Supplementary file notes

Annotated plan (with mods).
Manual, 6 pages complete.
Previous scan version.
Review.

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