RE: Carb venturi limiting SPE26cc performance?
Oh dear, let me clarify.
I bought the SPE26 because it was dirt cheap over here.(this is not the BCMA version) at about US220. Now it is even cheaper, like US185. I already fly the G26 on my Super Stearman and it was priced the same as SPE26 then. But the Zenoah dealer got greedy and price shot to US270+.
Since I'm just into gasser I want to learn and tinker without too much of initial investment. Seeing how great my G26 perform, I have same expectation that it will at least perform similar but my finger was cross because SPE26 was very new then and being a chinese gasser at that. Granted that its much lighter, something like at least 1++ lbs lighter, I thought even if its not as good as G26 power, if the weigh reduction able to compensate the lowered power, why not.
I also bought the Zenoah G20 EI at the same time. Weight wise it was heavier than SPE26 by a few oz and 6cc lesser too. So I thought the G20 is a waste buy so I started to prep the SPE26 first on my showtime and I almost sold off the G20EI (lucky I did not, I will explain later). Flown the SPE26 at least 7-8 liters(2 gallons?). It was ok but rpm just too low. APC17x8 at max 7400rpm. I ask the Chinese factory and given the nice video they demo on hovering, they say their pilot also on 17x8 at 7400.
So then I help my buddy to setup his G20 and did some bench test.
The nos was ....SUPERB, SWEET! Right out of box, barely 10 mins run, we got APC 16x8 hitting up to 8500 and 16x6 at 8800. The response was crisp and starting was super easy. 2-3 flips it start. Once warm, just a flip. The SPE26 required almost 10 flips before I can any. Its actually worst than my magneto G26 on starting. Maybe its just my SPE26.
So I swap the G20EI into the Showtime, immediately it show the power it has despite a 4oz heavier than SPE26 and requiring a much heavier pack at 2450mah for longer flight where I was using 1400mah for SPE26. I did use an 8oz tank vs 10oz for SPE26. All in all, I do have more AUW with G20, but the power it generated was AWESOME. The vertical is almost unlimited. This is 2 flight after 1 tank run in on ground. Factory say just flight, no ground run needed. It was reliable and superb transition. I was a very very very happy man!
The SPE26 is gathering dust today. The power to weight ratio claim did not cut it. even at 6cc more and lighter, its power/weight ratio is not there.
Lots of folk knock on the Zenoah engine without even testing and run them adequate to see how its perform. If zenoah can make the G20EI, its a matter of time, they make the rest as EI. Only in US, Zen is expensive. Go to Hong Kong (land of free tax) you will can get almost all zenoah at US100 cheaper.
Bottomline, I bought it because it was cheap and I get what I paid for. Lesson learnt.
Though I have not tested, if I were to put a stock G26 magneto on a same plane as SPE26 stock, my money is on the G26. It may be heavier but the power generated will surpass the power to weigh ratio claim of the SPE26. Why I say so? Its obvious isn't it. If the G20 is more powerful and heavier than SPE26 and yet smaller in cc, you can only imagine where G26 is even with the heavier magneto.
BCMA insisted that their SPE26 is substantially more powerful than G20 etc due to some internal work they enhance on and a different bigger venturi carb. So I thought why not inquire about the carb because if another 30-40bucks spent can get another 4-500rpm on that 17x8, then I would go for it otherwise the SPE26 is just gathering dust.
On picture wise, my SPE looks exactly like what BCMA have on their Version III minus the ignition.