NEWBIE engine sizes 2stroke comparedto 4 stroke

[Ron Willets]

 
 HI could some one please clarify for me equivilent engine sizes when comparing a two stroke against a four stroke .

   I have a international sailplanes cessna 40 that is an unfinished project this belonged to a freind and was given to me about 15 years ago i also have an OS 26 Surpass 4 stroke and was wondering if this could be used  

 

i am trying to get back into rc flying after a long interuption due to the usual family expense restaints and lack of time .

 i bought the os 26 about 16 years ago and it was in a junior sixty which while i was learning to fly disasterously flew out of range after only just being ran in on the bench

 well the sixty was totaled but the engine got off reasonably lightly broke prop and  twisted the light dural mount plate the engine was fixed too .

  in short im wondering if i could pair the cessna and the 26 four stroke  if my suspicions are correct the four stroke would have more torque  but would lack the ooph

                                 Regards Ron

[simon barr]

Hello Ron, and welcome.  I'm afraid your 26 four stroke won't be enough for the Cessna which needs a forty size two stroke. The equivelent four stroke would be around the fifty to fifty-five size.

[Ron Willets]

 Thanks for your advice simon had a feeling this was the case

   have also considered weather this cessna which by the way has a 60" span would be suitable for an electric power train at a sensible cost  i already have all radio equipment reqd and would be happy to spend in the region of  £100 to get started in electric

    at this point i have no idea if this is a realistic budget and what i could get for that sum of money

 ie    suitable size brushless motor

        e s c

       lipo packs to match   preferably  at least two of them  one in use one on charge

        suitable mains / feild charger

 

if i need to shell out more than this i might be better to look into an rtf and cut my teeth on that for a while

a freind told me his 8yr old grandson learnt on an electrafly  which also comes whith a sim which would be really helpful i think  these were not around when i last tried to learn to fly

  

[Ernie]

Hi Ron,

 

Your 26 OS four stroke is lovely wee motor that does need a home. Why not build something like a powered glider for it...slow, easy to fly, and great fun.

I dont think (Though, I'm no expert, as I'm just trying out electrckery) that your budget is enough. I've spent quite a bit more at the excellent Puffin Models for a brushless outrunner, and all the bits for a 2m powered salplane 

 

ernie 

[simon barr]

Hello Ron.  If I remember correctlly, the International Powerplanes Cessna was built quite heavily, (no cnc cutting etc in those days), but flew very well. Because of it's weight, I don't think it will make a suitable electric conversion. You would need a big motor and even bigger batteries...

Your idea of getting an "all-in" model,(model, radio, batt, charger etc), is a good one...there are lots of good models out there, but a few dodgy ones aswell.

 

[andy watson]

I'm sure someone will jump in to start arguing about electricity vs glow, but for £50 you could buy an OS 46 LA engine.  That would bolt straight into your Cessna, it's OS so you know its the best make possible. 

 

I am happy to be corrected, but electricity on a tight budget seems like a frustrating affair- the guys that get it working well do seem to have made a significant investment in chargers, spare batteries, charging battereries etc. 

 

Anyway, to answer your original question, you can broadly group engines into the following classes:

 

.25/.40/.60/.90/1.20

 

A 4 stroke engine is a replacement for a 2 stroke that is one "group" smaller.  eg a 90 4 stroke is the same as a 60 2 stroke. 

 

That is a rough answer.