We all have models which we plan to build "one day", or maybe even build again "one day". This one for me falls into the latter category. By the way, it's an American free flight model, not the RAF biplane!
In the late 1930's and early 1940's, free flight power was becoming popular in the USA, whilst power flying in general was banned in the UK during the war.
In the United States, most engines were 0.6 cubic inch capacity (that's 10cc in new money), and ran on petrol, needing onboard batteries, coil, condenser, etc. The method of flying was similar to the free flight power of today & a limited engine run, usually 20 seconds, followed by a timed glide. For this size of engine, the rules stipulated a minimum weight of 3lbs.
Most models turned out looking somewhat similar to the high wing light aircraft of that era, rather like Bill Dean's "Southerner". Pylon models such as the "Slicker" had not yet been developed.
The original Gladiator which was designed and built by Maurice Schoenbrun, won the 1940 Chicago US Nationals and subsequently appeared in plan form in the following year's AIR TRIALS magazine. In a special edition of RCM&E, around 1982, a scaled down RC version was published.
Back around 1990 I built a half sized, tissue covered 30 inch wingspan version, powered by an 0.46 cc ED Baby, sporting two channel radio on rudder and elevator. In calm conditions the plane performed really well, but one blustery day at Calder Park, unable to penetrate, it drifted backwards towards the Redmoss masts. There was no way of stopping the engine, so I watched helplessly as the Gladiator eventually hit the roof of a house, falling to bits in the garden. Heck! It had always been my intention to build another one, maybe full size!
Second time around!
Enter Alan Stewart with his "Southerner", a very successful vintage electric conversion, which provided the spur I needed to start on my full size version of the Gladiator. It was meant to be a winter project way back in November 2003, but it wasn't until September 2004 that the build was finally complete. So what, apart from being a slow builder, took so long?
To convert the model for electric flight required a redesign of the nose area, to permit the battery to go in and come out. Also, having come down a size in cars (now driving a Ford Ka), I felt that the tail-plane had to be removable. Interestingly, the original had a removable tail, held on with rubber bands, but an RC element would require accurate location of tail surfaces and easily-made connections. This took some time to work out but was worth the effort and as one club "Guru" asserts, "if the surface is removable, then it won't break!" We will see!
At my age I've discovered that there are some things that I can't do quite as well as I used to. Covering models is one of them! The original had been covered in Japanese silk and then doped. As the open framework needed some additional rigidity, Fibafilm seemed to be a suitable and less messy alternative. Covering the fuselage sides was okay, but the Fibafilm would not easily go over the curved top and bottom sections, to Solarfilm was used there and also for the tail surfaces. The wings were no problem to cover except at the tips, where once again Solarfilm was used. For the undercambered lower surfaces, thinned Evostick holds the Fibafilm in place and this seems to have worked well.
Although Fibafilm and Solarfilm are manufactured by the same company, the colours don't quite match - no doubt club members will congratulate me on the subtle use of contrasting shades of red!
When Mike Pirie first saw the plans he suggested that the nose be lengthened, the original model having a very short snout which held a heavy petrol engine. Mike was also sure that my proposed 7 cells would never move it. He was right on both counts! As built, she was very tail heavy and my 7 cell pack failed to even move her on a smooth floor. So yet more delays whilst I added a 1.5 inch extension to the nose and moved up to a 10 cell pack. Moral && listen to Mike!
Finished at last and waiting for calm, dry weather &&. the completed Gladiator's vital statistics as follows :
60 inch wingspan
4.5 lbs AUW Speed 600 motor with 2.5:1 gearbox 1
0 x 7 Master Airscrew electric prop 10 x 2000 Nicad cells
She flies! At Calder Park on Saturday 7 th October, a short and obviously underpowered flight took place. Delighted to report that despite the lack of power the Gladiator appeared to be a nice stable flyer, and by way of a bonus, was captured on video by George Whelan. I'm now hoping that Santa brings me something a little more powerful than a Speed 600!