Robin Hiern's RH-11 is a home built 2cc model aircraft engine made especially for winning Australian Class 1 speed competitions.

It's had some success too, powering the fastest Class 1 speed model at the 2002 Australian Nationals, and capturing an Australian record of 246kph on the new long lines!

Robin's aim was to make a better motor than the fastest commercially available for class 1, the O.S. CZ11PS.  Features of RH-11 include an 11mm diameter crankshaft giving a strong shaft and large gas passage, a thick walled brass chromed cylinder liner, a threaded head hold-down ring, and a front ballrace held in place with a LH threaded ring nut.

Materials used:-

Crank - EN25 nickel chrome steel
Liner - Manganese bronze, hard chromed
Piston - Mahle 138 18% silicon
Case - LM25 alloy heat treated
Conrod - 2024 aluminium

RH-11 turns a 73mm X 6inch single bladed prop at 33500rpm on 60% nitro fuel.

The photos at right:

1.  A view of RH-11 from the front.

2  Side view of the same engine.

3.  Exploded view of complete 2cc speed motor, and the knurled pin tool used for tightening cylinder head and front bearing ring.

4.  At top left is a mount used to hold case for machining liner bore and head retaining thread.  At top right is the alloy split plate pattern for casting case.  At bottom right is a case casting as taken out of sand mould, and at bottom centre is the casting with riser trimmed off.  A machined case, crankshaft, and conrod are at bottom left.

5.  The case mounted on a jig on a faceplate in lathe for boring crankcase for liner and threading for head retaining ring.

Click any of the pictures at right to see an enlarged view.

   Speed models


Developed 2003, revised 2005 by David Kidd.  Your Webmaster is Ron Chernich.