Cermark Ultimate – by John Miller

I have long been seeking a suitable replacement for my beloved Galaxy Domino, which went to that final hanger in the sky three years ago when the engine died in an unrecoverable position. I replaced it with a Seagull Super Stearman, which didn’t last long due to its brick-like flying qualities and another engine cut. Then a WOTs WOT, which I never really took to, switching itself off in mid air, once again leaving me sports biplane less.

In early February my wife had gone to the West Indies (no, she went of her own free will) leaving me with a kitchen that could be used as a workshop for a whole fortnight. I felt my plastic flexing, so I went down to Spire Models and came back with the Ultimate. First thoughts on opening the box were, you don’t have to join the wings, that’s already done, and it is extremely lightly built; if you aren’t happy about your landings go away and practice before you fly one of these. Don’t ask me how I know, but see the flying section.

Missing bits: A glaring omission was the parts list to check the kit contents against. As the covering in the bottom of the fuselage has to be cut out to route the closed loop control cables, a piece of covering material to fill in the hole will be required – none was included. Decals are mentioned, but there weren’t any in my kit. Finally there was only half the number of ferules required to make up the control cables. I e-mailed Cermark with these observations, giving them my address so that they could send me the missing film and decals – I made the ferules myself. There was a quick reply, telling me that the instructions were ex Dave Patrick, and that he had turned the  production over to Cermark. They had decided to do away with the parts list and the decals. There was an offer to send me the missing covering material, but I’d already found a bit that was near enough the same colour, so I told them not to bother. Full marks for replying though.

Quality of bits: Very good. I didn’t feel the need to substitute anything. The only failing was a duff thread in one of the captive nuts supplied for the interplane struts. Warning though – you get exactly the number of fiddly little nuts bolts and screws that you need. I swept the kitchen floor before I started, which made it easy to find the bits I dropped.

Extra expense: The intended engine was a Supre Tigre 51, which had been extensively (and expensively) rebuilt by Mick Wilshere after a crash into the hard dry soil (remember when soil used to be hard and dry?). The lines of the Ultimate begged for a proper Pitts type silencer at £30, so I bought one from Just Engines. Then the instructions suggest the use of small powerful servos. Luckily Hitec HS-85BBs met the spec (over 40oz-ins), and Al was selling them at a discount, but it was still another £56 for four of them.

Armed with the bits, I set about construction, following the instructions, but not necessarily in the order given. First I mounted the engine, which you are told to do last. My reasoning is that if you do this first you aren’t banging the tail surfaces against things while you do it. The cunning plan suggested in the instructions didn’t work. You are supposed to put the engine inside the cowl while mounted on its bearers, centre it and then cyano the mounts in position before drilling the holes. There was no way I could see of dropping cyano inside the cowl to do this, but the cyano idea appealed, so I glued the mounts in a guestimated position and then put the cowl on, and measured how much I had to move the mount to get the spinner central (it is difficult to do a proper measurement due to the side thrust.) The shape of the Pitts type silencer meant that I had to cut away a lot of the underside of the cowl to clear the two  exhaust stacks while sliding it on. I debated whether to glue the bits back after the cowl had been finally mounted, but this is a sports model, and if you need to take the cowl off at the field you don’t want to have to take a hacksaw to it. The worst bit of the kit was the way the aileron servos are mounted. They are fixed to a plastic tray, which is then screwed to the wing. There are wooden rails inside the wing, which broke when I tried to put in the screws. I cyanoed extra liteply rails inside the wing, but you shouldn’t have to do that in a kit of this price. The little bits of wood that were to have to servo screwed to them before gluing them to the plastic cover seemed a bit Mickey Mouse. Luckily the Hitec servo comes with a suitable mount. Servo tape and a couple of nuts and bolts made a belt and braces job of it.  made up my own switch plate rather than cut a hole in the structure. When it came to the closed loop controls, I thought it would be fiddly, but it was very simple, although it was easier to feed the cables in from the back rather than the front as suggested in the instructions. I used 3” wheels rather than the 2” wheels supplied, which must only be suitable for concrete and cricket pitches, so that meant the spats had to be omitted. No doubt it would be possible to assemble the Ultimate at the field, but it is small enough to go in the car in one piece, and so I choose to leave it like this and hang it on the wall for storage.

The weight of the complete model came out at under 5lbs in old money, a full pound and a half lighter than the Super Stearman with the same engine. So, the 64,000-dollar question – how did it fly? The answer is, very well, once I’d moved the C of G back to the rearward recommended position. With it too far forward flare out on landing was difficult – or in my case impossible. For the second flight (after gluing the undercarriage back on!) I moved the battery back, stuck 30gms of lead to the rear, and increased the elevator throw. Now it will flick, and flare out properly. The ST51, with a 13x4 prop, appears to give unlimited vertical performance. Is it a worthy replacement for the Domino? In a word, yes.