High Altitude Launch

I weight 240 lbs and fly from a field that’s at 5300 ft MSL. If I buy an SP140 and attach it to a light (35 lb) trike will I have enough power to cruise without exceeding the 10kw max continuous rating of the motor? I have a Gin Condor 37 and a APCO Game 42 for wings.
Does anybody have any experience in these conditions? How many kw do you need for level flight at say 500 to 1000 ft AGL?

generally considered at eppg. if you continuously load a single 4 kw battery with 10 kw, it will soon be dead after a few cycles because it constantly overheats. yes, the motor can hold your total weight with trike wings that big in slow cruising if you use 2 batteries with 4kw. or at least 6 kw/h battery. but it will always be the case that you will need full throttle to take off safely. I personally would not recommend a sp140 motor with a trike and a large battery and heavy pilots. here is a motor with about 5-6 kilograms and 150 cm three blades a more efficient version because the motor can run in an ideal efficiency and you have a lot more thrust at the start to take off safely.


Ya it can be done but I would recommend 2 batteries. For flying solo the ESC and motor would be fine and if you can fit a 150cm prop that would be nice also.

Zach and I did do a tandem flight with stock SP140 and stock 140cm prop. Definitely wanting a bit more climb rate. Did also try with a 150cm prop as in the video below. Zach and I are about 180+200LBS so definitely a bit of a load for the stock setup. So with the 2 batteries trike and our weight it was around 580lbs, so around 3x what it was design for. Also for that tandem flight we forgot to turn on one of the batteries so just one battery was being used so definitely a bit much for it. For takeoff we were pulling about 25kw and for cruise it was about 11kw.


I’m curious about the motor suggestion by bratwurst, not sure what happened to it.

It’s just my personal opinion on eppg after over 10 years of experience. as a comparison: you can have a lot of fun with a 100 hp car alone or with a full passenger. sometimes pull a small trailer with it. but if you want to pull a horse trailer permanently, the 100 hp car will have quite a bit of wear and tear because it is constantly being moved at the power limit. a 150 hp car would make much more sense here and doesn’t cost much more, but has enough reserve.

another example: you can also fly with a trike and a top 80 with a total mass of 150 kg. the speed will always be very high, so the pistons, cylinders and bearings will have to make a lot of movements. the hourly output will therefore be very low up to the 1 main service. if you take a 185 monster, you won’t have any trouble with 150 kg and you will make almost half less movements with the piston, bearing, etc. it will last for a very long time.

the same applies to electric motors and batteries.

what is special, however, is the electric motor as an example: if you take a 12 kw motor with 4 kg and operate it with 8 kw, the efficiency will be around 90%. if you operate it at 16 kw, the efficiency is below 80%, and an enormous amount of heat is generated. at 20 kw it only works for a very short time, if you do it often, the motor will soon be demagnetized or the windings will slowly burn out

if you take a 16 kw motor that weighs 5.5 kg and runs it with 12 kw, the efficiency will be over 90% and very efficient. if you need 16 kw, that’s also very possible with an efficiency of more than 85%.

in short, 1.5 kg more weight in the engine makes a huge difference in long-term performance and efficiency.

this is the reason why manufacturers of aircraft motors in have been offering different sizes of motors for over 10 years. 3.5 kg to 7 kg and more. this is the only way to make sense of effective electroflying. if you often hear disappointed pilots who can only fly 35 minutes with their eppg with a “1 h battery”, it is partly due to the wing, flying style, but also often because the motor is too small for the respective purpose.

especially when it comes to trikes. because the cage has to be reinforced, the rescue parachute is heavier, etc. a lot of weight is added. It is especially when, as the questioner says in 1 postings, he wants to start at a great height, you need additional power reserves. the most dangerous thing is starting with a trike if you don’t have enough power. clearly no problem on huge meadows. but very few pilots have that.