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I may have accidentally created a monster...

JennyC6

Well-known member
#1
My LHS is known for dealing in used as well as new models, surface and air alike, and I have bought two used planes for next-to-nothing from this place before. My first, an Aerostar 40 with an OS 40FP for $40, has flown since I purchased it; remaiden was during the 2pm Saturday gaggle at FPVFest 2019.

The second is the topic of discussion here: A Sig Kadet EP-42 for $30.

SIG designed this thing 20+ years ago to be a small electric trainer, as such it weighs bugger all and the factory power system was a brushed Speed 400 motor that put about 45 watts into the prop. 7-5-2 APC, 9000RPM, gives about 250g of thrust. This was enough to fly the model quite nicely, but with the typical docile nature a trainer would have. At time of purchase, mine had an EFlite Park 400 outrunner on the nose....naturally, being the nitro nut I am, that got ripped off right fast and in its place went an AP 061 engine which is swinging a 6-3-2 MAS prop.

I think this might just be too much power for the airframe. If my engine is running even half as good as it should do I will have about 70 watts or so at the prop and around 300 grams of thrust in a 700 gram airplane. This was the case last time I took tach readings on it, 13,500 on a 6-4-2 TF wood prop which should equal about 14,500 on a 6-3-2. More than enough to fly it. I made a couple more adjustments to the setup(Replaced the glow plug insert and got muffler pressure working) and test ran it today without a tach; my ear tells me it's zinging up like there's no tomorrow and the daggum thing wants to rip itself out of my hand! I'll run it again tomorrow with my tach involved to get exact numbers, buuuuuttttt....


Anyone have any tips on how to hover an airplane?

If my tach shows performance in line with what this engine is capable of(Manufacturer spec and most users all concur that it's good for about 1/4th of a horsepower and will happily rev past 20k), I'm looking at about 700 grams of thrust in this thing, give or take a few. That's...roughly 1:1 with how much it will weigh with a full fuel load(I crammed a 5oz tank in the battery compartment).