SwampFlier-RCU

"Flame suit on"

I was browsing on the newbies forum and saw a nice trainer disguised as a tree stump (crashed sraight down and stayed that way) and that got me thinking....

Albeit planes are made to fly and not to crash...... crashes often happen and usually when that happens I dust and clean my glow engine repair the plane if possible and keep on flying the thing.
I would think that electric motors are more sensitive to close encounters of the third kind with trees, runways and other objects.... I think the casing is thin, coils are not shock proof, and the crankshaft (not sure what is called in elecrtic motors) driving shaft?? appears to be of smaller diameter since it does not need to be designed to absorb the combustion shank.....

So what is the survavility of an electric engine in a crash??

tIANci

They both can hit as hard and break as hard. I think there is hardly any difference. Why?

EP planes are much lighter if you talk about foam etc so when they hit the force is less BUT the material is also softer and easier to break compared with ply. So its about the same. The ONLY advantage I see in foam/light balsa EP planes is that if the damage is light you can just CA it all back at the field. As for the motor, I have yet to bust one badly. Shafts tend to bend more than our glow engine shafts but the electric motor shaft is pretty cheap to replace. Usually its the smaller motors that we bend.

Its about how you fly. A newbie just did a 9/11 with his trainer into a wall ... not much of the engine was left.

scottrc

I'd have to say a electric motor will suvive to run again after impact more then an engine. The motor is mounted where no attachment points are affixed to the case causing the motor to "float" with the impact. The case is solid and all the parts are latitudal, so the engery from the impact will travel through the motor evenly resulting in maybe the rotor and can seperating from the backplate. From my experience from racing electric cars, all I had to do was put the "guts" back into the can and do a little resoldering to get the motor running again. An engine has perpindicular intersections, at the mount, the connecting rod and cylider, carb and intake, and exhaust manifold, that causes the engery from the impact to dissipate within the crankshaft and engine case causing a failure point to happen within these areas of the engine. It also doesn't help the fact that engine cases are castings, which are pourouse, that enhances the chance of failure from a sudden impact.

I would say that you could probably be able to get the electirc motor running again without replacing major, expensive, parts after a direct impact than a engine.

P-51B

My Feedback: (5)

The only difference I have noticed so far is that in anything more than a light crash, LiPo batterys tend to get ruined. Crash an e-plane your out a battery pack, crash a wet fuel plane and you may be out a few ounces of fuel if the tank ruptures.

SwampFlier-RCU

Interesting replies; I was thinking of bigger planes not backyard fliers where speed and mass is not substantial (for the backyard fliers).

let's say a 66" wingspan plane with a .90 two stroke engine vs. an equivalent electric setup

Cars are different because the motor is usually in the back so that any head on collision is absorbed by other parts of the car and not the motor itself..

doh.doh

I've busted a couple of crankcases, countless OS .46FX needle valves, had one come off at the engine mount and seen one head torn off of a car (these are all fuel). Zero for electric motors. I think the main difference is that the gas/glow motors have many protrusions, ie carb and head, and main shaft has more leverage in relation to the mount. Also, electrics have the fuse (generally) protecting them, and the prop as another shock absorber.

tIANci

Swamp - if you wanna use 90 sized planes for comparison I will say both damage as hard. For EP there is the higher risk of losing your batts, they are not encased in a hard housing and in a crash they will probably deform. ESC will usually survive as for motor, well depends how you hit ... the AXI 4130 (90 sized equivalent) is a pretty tough thing.