Originally Posted by mac2286

Great, what are you going to power it with? Keep posting for us if you don't mind. I would like to see a lot of builds using this method.

Sure, I will post when I can, I'm a pretty slow builder so I'm shooting for a Spring finish. I will have to wait on what the final weight will be before selecting a motor for it. It will be electric though. radfordc thought the 1/5 scale should be under 10 pounds and a 30-35cc engine would work OK. I don't know what that would convert to for electric motors but I'm guessing something in the 600 watt range would be plenty.

Larry

Extreme flight has a very good line of motors that are called XPWR motors. They have 30CC, 35CC, 40CC and 60CC that definitely compare to the 35 through 60CC engines. On 12S, the XPWR 30 puts out around 3000 watts swinging a 20X8 Xoar or Falcon would prop. You can find the manual for these motors here.

SteveT.

Originally Posted by slow and low

Sure, I will post when I can, I'm a pretty slow builder so I'm shooting for a Spring finish. I will have to wait on what the final weight will be before selecting a motor for it. It will be electric though. radfordc thought the 1/5 scale should be under 10 pounds and a 30-35cc engine would work OK. I don't know what that would convert to for electric motors but I'm guessing something in the 600 watt range would be plenty.

Larry

A good rule of thumb is 100 watts/lb for a trainer/sport type plane. You will need more than 600 watts for a 10 lb plane. 1000 watts might fly it, but 1500-2000 will fly it better. These planes need plenty of power to perform like you want them to...you should be able to hover like a 3D plane. With my 1/3 triplane, a 50cc motor at 20 lbs barely flew but a 120cc motor at 30 lbs flys great. With too much power you can throttle back; too little power and you can't do anything.


Here is the 30cc size motor I just bought... http://www.hobbypartz.com/96m608-big...BoCg7MQAvD_BwE

Originally Posted by kitscratchfevr

Mac I didn't see how you tied your hood cabanes into the fuse.. but if you have that good and strong it should work... There is no doubt with the foam build the hard points and cable will be the key to being strong enough... just like the full scale

I should have taken a picture before I closed that up. I have a3/16 ply cross brace epoxied across the top of the 3/16 inch ply side formers. The cabanes are glued to them and 1/2 inch hard wood doublers in the corners. I think it will hold.

Originally Posted by radfordc

A good rule of thumb is 100 watts/lb for a trainer/sport type plane. You will need more than 600 watts for a 10 lb plane. 1000 watts might fly it, but 1500-2000 will fly it better. These planes need plenty of power to perform like you want them to...you should be able to hover like a 3D plane. With my 1/3 triplane, a 50cc motor at 20 lbs barely flew but a 120cc motor at 30 lbs flys great. With too much power you can throttle back; too little power and you can't do anything.


Here is the 30cc size motor I just bought... http://www.hobbypartz.com/96m608-big...BoCg7MQAvD_BwE

Thanks for the info, I was hoping I didn't need such a big motor but I respect your opinion. The only experience I had with large scale was watching a 1/4 scale Tiger Moth flying around with an OS .91, I was pretty impressed. Now that I'm smarter, the TM was flying scale and pretty sedate, the SE5A is a warbird and should be flown as such.

Larry

Plus the Moth had a "real" wing, not just a flat board. You don't get as much lift from a flat wing and need more power to perform.

Here is an article on flat plate vs airfoil performance: https://aviation.stackexchange.com/q...lat-plate-wing

Bottom line is a flat wing has much less lift and much more drag.

Good read.... thanks

Larry

I'm kicking around the idea of using KFm-2 airfoils on my 1/5 SE5A. What are your thoughts on this for larger scale planes? I h ave used them on 40" planes with dramatic success.

I also need advise on what servos to use and battery size for a 160 motor. Specs call for 14S but I was thinking of using two 6S in series.

Photos to follow, I got the tail feathers done and the lower wings done, will start on the upper wing and fuse today.

This is the plane I'm modeling, I have a small 250 size that I did for indoor or low wind days.

I have also wondered about the KFM airfoil....someone needs to do it.

I recently helped my friend convert his 1/4 scale Cub to electric. We used a Turnigy G-160 motor, 100 amp ESC, and 8S battery. The performance was ideal....cruise at half power and climb straight up at full power.

I would think that a 10S or 12S pack would be plenty for the SE-5.

I am getting ready to rebuild my Triplane wings this winter. Think I will try the KFM2 airfoil and see how it does.

Just how much of the wing gets the top put on it? and what glue would I need to use to glue the top part on. I wouldn't mind trying it on mine.

I use 50% for the KFm-2 and I put mine on with gorilla glue. Lots of good info on the Foamies scratchbuild forum for KFM airfoils.

Larry

Larry, I will let you do the test with the KFm-2 wing. I will fininsh mine the way it is. That looks good.
Worked on mine a little this evening. Got the engine area fuel proofed, and the firewall drilled and the engine mounted. Got the front cowling just about ready to mount and the gas tank area fuel proofed.
Finish up the rigging, hinge the control surfaces, install the electronics, fuel system, and test fly it. Not going to paint it till I see if it is going to fly. If I get the time should not take to long. But a lot of things are getting in the way.
Jimmy

You are boogieing right along Jimmy, anxious to see yours fly. I'm sure there will be others before me with the airfoils and having played with them before, there is no doubt they will work fine. More important than lift, to me, is the extra strength they add for the little extra weight they add. If the bottom wing was one piece, I would be tempted to forgo the rigging but with the bottom wing plugging into the fuse, rigging is a must.

I will have mine painted before flying just because its going to be a long winter here and I'm shooting for a March maiden. Something to keep me busy.

Larry

Can someone define the KF2 wing? I am curious about that?