Hi Graham If we are talking about the Graupner Brushless Speed 500 ECO no 7295 https://www.graupner.de/Brushless-Speed-500-ECO/7295/ then yes the Kv is 500 which equates to 7500 at 14.8v. It's 50mm x 80mm with a 6mm shaft so really a heavy duty motor and in a Aeronaut Queen 36" still much too big and powerful. You really need to resolve the drive train and shaft problems and this will be easier if you choose a motor of smaller diameter and power. A 36xx or very similar size motor at about 1000Kv or less (500Kv with 14.7v) will be ample. The prop should be less diameter than the motor. There are many examples of 36" model boats on this site and I do believe the majority of our members have used similar set ups, to those we have suggested, in their models with a large degree of success. It could be we are talking about a different motor as you refer to " the small outrunner motor". If so please post a link to a pic of the motor.
https://youtu.be/KRT8-mfjY6E Just uploaded another running video! :) not too exciting but gives away the stage of completion XD, a few more videos coming soon, and hopefully the build part 3 in around a month when I've compiled all the footage! t
[Score: 9/10] 30"/4000g Aeronaut Pilot LKBM 04 Capable of 12mph and a runtime of 50mins Twin Propellors (4 Blade 30mm) Direct Drive to a Graupner 600 speed (4 Blade) Powered by NiMH (8.4v) 5Amp/h Batteries Controlled Through MTroniks (40Amps) ESC - Comments: Took me 7 months to build. Has twin esc so I can control each prop individually, twin rudders, a sound system, horn, working anchor windlass, 4 individually controlled lighting setups (cab / dashboard lighting, navigation, pilot and search lights), spinning radar etc. She gets up well on a plane, probably a bit over powered!
Try Dens Models Website if you are looking for a small outboard motor. He is the dealer for the Aeronaut range that do both boats and aircraft. I have seen an outboard powered model in his range and he is situated on the Isle of Wight. Den is an excellent person with a longstanding interest in model making .😊 Boaty.
[Score: 8/10] 23"/1200g Aeronaut Spitfire Capable of 20mph and a runtime of 10mins Single Propellor (2 Blade S Type 25mm) Direct Drive to a Hobbyking outboard (2 Blade S Type) Powered by LiPoly (7.4v) Batteries Controlled Through Turnigy ESC - Comments: This is my aeronaut Spitfire. This was my second build following a lifetime of RC Aircraft. The kit was a joy to build with really nice quality wood and components with good instructions. Sourcing the outboard was a challange but Hobbyking had the solution. running on 2 x 7.4v Lipo and Turnigy water colled ESC this should go very well. Not had a chance to run it yet, but the bath test has shown no leaks and sits well in the water. Actionman and his clothing, helmet ect where sourced from eBay for about £12, bargin!