Magneto Zenoah 26

[Nick Reeves 3055]

hi guys,
look for some prop advice. i recently picked up a z26 magneto and it is destined to go into the T240 that i havent built yet. i normally run an 18x8 on a the 26 but what would be the ideal prop for the big slow model? will it turn a 19 or 20 x 6??
cheers
nick

[Phil Clark]

18 x 6 would be the normal starting point for a mag 26......the electronic version will happily do a an 18 x 8 though

Several 1/4 scale Cubs in my club (slow), all on 26's......all run 18 x 6's

Phil

[Nick Reeves 3055]

hi phil,

cheers for that. its got a 18x8 on it just now on the test bench but ill bring the pitch down once its ready to fly

nick

[Clive Hall]

I built two examples of the T-240, both powered by Zenoah 23 and both well matched by an 18 x 6 prop. I know of one that had a Zenoah 38 which was fine, so the 26 should be ideal. I believe the 6 inch pitch would suit the model's airspeed better than 8 inch.
The structure of the model as presented in the kit leaves a lot to be desired. On my first one I gradually made changes which made it much better. The second one was built from the start with all the changes included.
A few points for improvement:-
The struts are attached to the face of a wing rib. One bumpy landing will result in some awkward repair work. Attaching them to the bottom of the main spar is far safer.
The elevators are too small for a good landing flare - I doubled their chord.
The cabane structure is weak. I beefed it up with carbon fibre cloth/epoxy resin on the faces of the relevant formers.
It was published about 10 years ago in RC Model World, and I think I can find a copy of the article. If you would like some hints on how to improve the model P.M. me and I will send the info.

[paul needham]

Was that the one with camo top with yellow underside featured in the magazine ?

[Clive Hall]

Paul, yes, that was the one. The earlier one was finished in olive drab with invasion stripes. Not a great aeroplane, tended to fly like a garden shed.

[Martin Waller]

I use the Zenoah 26cc in WW1 and my sons in law use the same in WW1 and Extra 330.

Best prop is 18 x 8 Engle silent pro obtainable from Fighter Aces was extremely expensive but now similar price to Majelik (spelt incorrectly).
18 x 6 Majelik gave 8,700rpm and is the air sounded over reving. 18 x 8 Mejelik gives about 7,700 to 8,000 static. The Engle with its very thin blade gives more revs and unbelievable thrust. At an LMA show with the 26cc and Engle prop my helper thought I had the 45cc Zenoah.The Engle gives about 8,000.
An 18 x 6 Mejelik is great for the 23cc Zenoah and is a perfect match at about 8,000.

I have not had much success with wooden props on these but the Mejelik props give same revs as Metz props but the Metz wood give about 60% the thrust. The carbon blades are thin so energy going into moving air back in direction of travel rather than slapping air with thick blade.
I use Mejelik carbon on virtually all my petrol planes (14) and Engle on Sopwith Pup. The Mejelik 19 x 10 is great on the Zenoah 38cc giving 7,200rpm and incredible thrust.
Hope this helps we have experience of 1 x 23cc and 4 x 26cc Zenoahs all magneto ignition over 800 flights on these props. Zenoah 23 and 26cc are high reving engines they will not be loaded down, if they are they are impossible to tune and set the carb. Do not try a Beila 18 x 8 as it is too hard to turn may work with a really well run in 26cc. Ours we new when we tried, fitted Mejelik and ran really well.
Hope this helps.