David P Williams

Yes I'm not keen either. I might be saved by the spacious American cockpit opening which might give me enough room to manouvre the tank in and out. Otherwise it's all a birds nest of formers and stringers covered with thin ply simulating aluminium panels around the front. Tricky to provide an access panel without compromising the structure. I think I'll have to give up on the idea of full depth cockpits anyway as they are really the only access into the fuselage so I think false floors with servos, glow unit, batteries etc under them will be the way to go. I will replicate the 'baggage' hatch behind the rear cockpit but probably only to hide switches in.

Thanks Jon - it's getting triangular stock reinforcement inside the box and round the box to firewall joint too. The kit supplies a fibreglass bandage to epoxy round the front of the tube, so that will go round the front of the box too. The box also builds in 2deg right and 2deg down thrust as recommended by Flair for larger/more powerful engines. Agonising over the tank at the moment - the kit supplied one is 20oz which I'm sure won't be enough. I have a 24oz and a 30oz. Cymaz reckons his Evolution version does 2oz/min at full throttle. Problem is, the tank is inaccessible once built. I considered having some sort of removable front to the engine box, but decided on strength rather than convenience.

After several days of pondering, headscratching and scouring the internet for info and useful pictures I decided to ditch the tube mounting arrangement and spent a happy hour or two with the CAD designing a replacement engine mounting and revised front two formers. A further happy day or two with sheets of ply, bandsaw and scroll saw and a few scrap pieces and design changes and I ended up with something I'm happy with. Also took the opportunity to beef up the undercarriage strut mountings. Just need to epoxy this lot together, work out a tank mounting platform, fuel proof the inside of it and then crack on with building the fuselage. I also invested in this from Just Engines for starting and to keep the fires lit at low revs

Hi Manish - the Martin Tuck plans were from the old Nexus Planse Service, now Sarik Hobbies here. They are not very detailed at all - little more than a three view with some framing drawn on, fuselage formers outlined and wing sections from which you have to derive the ribs by deducting sheeting, rib caps, etc. plus a sketch of the nacelle construction. Would build lighter than the Bates/Sweitzer plan I guess.

Progress so far - Tailplane and fin completed, lots of wrestling with warped liteply (surprise, surprise). The liteply parts are die-stamped very cleanly and accurately - I guess this was one of the early kits when the dies were still sharp! The fuselage section is just dry slotted together to check fits. The normal ply parts are CNC routed, and the various slots for longerons and interlocking formers are a fair by undersize. Fortunately, one of my Christmas presents was a set of Permagrit Spar Slotters, which worked fantastically well and made a pain of a job enlarging the slots into an easy one. The headscratching and agonising now is around the engine mounting. The kit uses a tubular structure made up of 1/16 ply rolled around a lamination of two 1/8 ply discs at the front and a 1/8 ply ring at the rear, which slides into the first two fuselage formers, allowing you to set the correct fore and aft position of the engine mount depending on your particular engine. Seems strong enough for the suggested Laser 180 at 1.25kg, or 2.75lb, but this engine is 2.85kg or 6.25lb, so maybe I need to engineer something stronger. The manual with the engine prohibits standoffs (the engine is already on three standoffs between the crankcase and the mounting plate). So - keep the tube setup, remake the front couple of formers of thicker ply without all the fretting out, with a second layer of 1/16 ply laminated inside the tube, or forget the tube setup and remake the front former in 1/4 ply and build a 1/4 ply box on it to carry the engine. The instructions recommend 2 to 3 deg right and downthrust for larger engines, so would need to build that in too. Keeps me awake at night! Lastly, an idea of the difference in size between this and my last build (I have built at this size before though). The tailplane is bigger than the wingspan of the TN Provost...

Thanks all for your contributions. It's amazing how many "little jobs" the other half can come up with the get in the way of modelling. A couple of questions for those of you running the Evolution engine - what is the fuel consumption like? What size tank do you run for what duration? If I use the kit engine mounting method the tank is pretty much built in, so would need to get it right from the start. Do you run onboard glow? They seem to add a fair bit of weight given the size of battery needed to run 7 plugs.

Hi Rod - Jon's 3 cylinder engines are just designs at the moment I believe, he's unable to get them into production just now. The first batch or two of the Stearman kits had some errors, including the tailplane incidence. I believe later batches were corrected, but the tailplane incidence should be between +3 and +3.5 deg to avoid carrying lots of down trim and the power climb problem. They also suggest up to 3 deg right and down thrust for larger, more powerful engines. The Flair Stearman webpages are still live, with the customer feedback, hints, tips and corrections here

Thanks Jon. I 'll have a chat with Morris about the run-in, if he says it's necessary then I'll work my way through it. Good luck with your prototype, looking forward to more info about that in due course. So - the start of a build, tidied up workshop, cleared bench, EXCITED As is fairly normal practice, the manual recommends starting with the tail group More info as I get to major points in the build.

Bert - I remember your complaints about the Evolution engine on another thread. Glad you think the Stearman's nice to fly though. Rod - Yes, I'm aware of the Saitos but as I said earlier this is about how it looks and sounds, and I don't do stinky petrol (yes I know I could use Aspen at the same cost as glow fuel)

Jon - if you did a 7cyl radial of around the correct scale dimensions I would of course rather buy that. This Indian engine may turn out to be a mistake, but it is the right physical size for the model, has the right number of cylinders, and looks fantastic, like a piece of jewellery. The fuel and "break in" advice in the manual seem to be the same as you mentioned for the Evolution version Like you, I can't understand why it needs such a faff. I normally take your view on "running in" - fire it up, tune it up and go fly. My engines have always been fine. Looks like I will have to get into mixing up my own fuel though, one way or another. I use Model Technics Lasermix 5 in all my engines at the moment which I think is 15% oil so mixing half with straight methanol would give 7.5% oil and 2.5% nitro I think. Will have to work out how to mix it oilier for first runs I guess. And yes, it's all about looks and sound - I won't be trying to prop hang. If you ever get the inline twin you have hinted at into production I'll be first in the queue - somewhere else in my kit stash is a TopFlite 1/5 89" P51 just waiting for that engine.

Manish - yes I know about the petrols - I bought this one from Morris. Stearmans have 7 or 9 cylinder engines, so if I'm doing the real radial thing then 5 cylinders won't do. The 55cc petrol is the same physical size as the old 35cc glow, too small to look right at this scale and possibly marginal on power.

Thanks everyone - yes, the first flight or three will be puckering. The engine needs 3 hours of running in before I get to that stage according to the manual. Yes Jon it's glow. The petrol version of this is now 90cc (same external size) so even more power and torque than I need, heavier with the ignition unit, and £700 more expensive (and I can't stand the smell of petrol anyway). If I use an onboard glow driver I guess the weight will end up the same though - the UMS manual says I shouldn't need one once it's run in properly, but hmmmmm. It came with a test report from the factory. It had a 20 min run, with a 24x8 Menz prop. 1450 idle and 5450 max. It claims 8.8kg thrust in the spec, so should be "enough".