Ultra Stick flying engine test bed!

[Mike.K 60]

I`ve acquired a number of new engines recently for up and coming new builds. I`m a tight wad so many of the new to me engines are often " pre-owned or pre used low time "new in box" or low use examples in good physical condition. Before committing them to use in expensive new models, as a rule of thumb, I`ve decided to commission and test them on a relatively cheap and proven air-frame. The Ultra Stick provides an excellent test platform with a wide Centre of Gravity range. Servos can be tail mounted to off set the weight of some of my larger capacity motors.

I have six and a half available Ultra Stick examples in The Hangar presently. The half model is accounted for as its scratch built fuselage is a near copy of the kit version but is devoid of its own dedicated wing. It therefore shares one borrowed wing from one of the original Hangar 9 kits. Chosen as a flying engine test bed, my No 3 example is a genuine Horizon Hangar 9 example complete with its own genuine wing and has previously been fitted with servos fitted at the tail of the fuselage together with extra large fuel tankage. As originally built, I`d fitted an inverted, hardly used, ASP 1.08 two stroke glow motor bought at one of our Club auctions for just £15. Although constructed over a year ago, this No 3 air-frame has never been flown.

Two new to me, four stroke engines have arrived here over the last couple of days. Destined for a Seagull Bucker Jungmeister, it is a great lightly used condition pumped Yamada140FZ four stroke lump. What a cracking engine it is. Constructed in Japan, it looks like a cross between a motor bike and the contents of a Bentley car engine bay. Its a stunning piece of top level engineering which is built like a tank!  Also purchased was a cheap and cheerful SC120FS unit. Japan meets China! The SC looks like a Yugo when compared with the YS 140. I`m not sure where that SC120 is due to finish up, but it certainly fills a gap in my engine stock.

Last night saw the 1.08 two stroke torn off the front of No 3. I flipped the motor mount over 180 degrees and fitted a new throttle rod arrangement to suit the YS140. Space was very tight between the rear mounted carburettor and the bulkhead but a workable solution is now in place. Good enough for a Government job!

I need a suitable propeller before sorting the C of G position. The rear mounted servos will help with that. In the fuselage, apart from the throttle servo fitted towards the nose of the model, I have a free canvass on which to mount the receiver and probably a 2600NiMh to power the radio gear. The battery can if required be mounted right back against the rear bulk head. The receiver can go anywhere to get a C of G that is best placed on a central position between the fore and aft C of G markings. This model is pretty uncritical as regards the C of G so that is a bonus point for this type of air-frame. From my experience flying my electric No 1 air-frame, even at the aft limit, the model is still reasonably docile provided you keep up air speed on the landing approach. The docile nature of the Ultra Stick makes it a very versatile model generally with great potential to handle a variety of engines of differing weights.

The YS140 mounted in upright position on the Ultra Stick looks quite outrageous. The carb spray bar is well above the centre line of the fuel tank. With a normally aspirated non pumped engine, fuel flow issues would no doubt become apparent. That is not an issue with this pumped YS unit as a running motor produces a puff of air from the crank case on every fourth cycle stroke. A simple fuel pipe fitted with a non-return valve leads to the fuel tank to provide a pressurized flow of fuel to the carburettor. Its probably as close as you can get to having a fuel injected engine! It is not necessary to provide a pressure feed from the exhaust as is needed with a conventional two or four stroke set up.

Here are a few images of Ultra Stick No3 now fitted with the YS motor. All I need now is to find a spare receiver, a 2600NiMh battery, an exhaust and a 16x10 propeller to make the thing flyable. If anyone has any large (15-17 inch) high pitch (10-14 inch pitch) propellers they wish to sell, please let me know.

Mike

[Mike.K 60]

Correction...make it two flying engine test stands!

I found my first prototype clone copy (No 6) Ultra Stick kicking around in the garage. I knew it was in there somewhere but only had to find it. It is a bit heavier in the tail than an original Hangar 9 kit built example, but that's not a big issue. This rendition is the roughest build of the Ultra Stick bunch, being constructed last year when I was under pressure due to my Father being in hospital. I recall being exhausted at the time and in the rare moments I had to myself, built this example as a sequential batch of two spare fuselages. This No 6 fuselage previously flew last year but at the time was electric powered. Lessons learned on this first scratch built example were later incorporated into clone airframe No 2. To confuse matters, the numbering of my Ultra Sticks doesn`t follow any logical build sequence. Numbers got slapped on them in random fashion when I began to have difficulty identifying each individual model....they all look nearly identical. The genuine Hangar 9 examples have "Ultra Stick" decals on the fins whilst the clones have no such identification.  At least now I can match the  two genuine wings I have to five similar fuselages. No 4 fuselage is my Hangar 9 kit low wing dihedraled conversion and No 6 is the terrifying, scratch built, twin engine "Scary Stick" monster. Get the drift? Consider yourself smart if you do!

As previously said, No 6 example is slightly overbuilt at the tail. I`ve subsequently reworked the fuselage by removing some sheet material on the top, sides and bottom. It is amazing how much  excess sheeting adds to the finished weight of the model. I constructed this fuselage from all the sweepings off the workshop floor so it has little value to me. I consider this fuselage to be the expendable example and would probably simply shrug my shoulders and laugh if it became a write off. The fact that this model is my least liked example and which I regard as something akin to a flying t##d, makes this fuselage ideal as another airborne motor test platform.

Having recently acquired a lightly used SC120FS motor via eBay meant I was looking for another test bed. A day of wood butchery now sees No6 converted from electric to nitro power. With the addition of fuel tank, engine mount, throttle push rod and some internal reinforcement of the F1 bulk head together with epoxy fuel proofing, this flying pile is almost ready to go into action.

Having written the above text in draft yesterday afternoon, given the passage of some eighteen hours and a fit out of the model last night, I`m forced to reconsider whether I was entirely fair about the No6 fuselage. With motor, tank, motor pushrod and servos fitted, the near finished model has taken on another dimension. The SC120FS motor is a heavy old lump and perhaps not unexpectedly initially produced a forward C of G. I moved the 2600NiMh battery under the balance point. Things improved markedly. I then moved the elevator servo to the tail...almost there.  I added a few lead balance weights which with the wing fitted, produced a perfect flying balance. I don`t like carrying unnecessary dead weight, so the rudder servo will also be moved aft and then the lead can be removed. I`m happy enough with that. Presently I`ve run out of 3mm clevises, couplers and 3mm solderable piano wire. A trip to Robs emporium will sort that issue.

With a receiver still to be sourced, this second flying test bed is ready to fly.

Mike