Help getting dads old plane to fly

[Greyhound247]

I could use some help to figure out which power pack (or individual components) to get for this plane. My dad built this in the 70s and never flew it! He was too afraid to crash it as a kid after spending so much of his money working a paper route to buy/build it. I'd love to surprise him and get it flying.
I've built the FT simple cub and am comfortable flying it. When I built the simple cub, I just bought the recommended power pack for that, so I'm not sure what size motor/prop/esc/battery I'd need for this plane. It is made of mostly balsa. Also, will 9g servos work or do I need something larger?
This plane has some decent weight/size to it: weighs 1165g total and has a wingspan of ~1470mm.

Appreciate your help! Can't wait to see the look on my old man's face when he sees the plane he built so long ago as a kid finally in the sky!

 

[Bricks]

What size glow motor is that, that will tell you comparable size electric to use. 9 gram servos will be to small, standard size servos are cheap used ones can be found ultra cheap.

 

[Greyhound247]

I don't know the size of the old fuel motor... this is what it says on the side

 

[alan0043]

What size glow motor is that, that will tell you comparable size electric to use. 9 gram servos will be to small, standard size servos are cheap used ones can be found ultra cheap.

Hey Bricks,

What do you think about using the FT XL Power Pack to get this plane up in the air ? This power pack works great on my Scout XL. The Scout XL wing spam is 58 ". The kit has 17gram servos. Uses a 3300mAh battery. Maybe add a flight stabilizer can also help. Just throwing out some ideas.

FT XL Power Add-on

Complete your XL series RC plane with the FT XL Power Add-On. Includes servos, motor, ESC, and more for powerful, climb-ready flights.

store.flitetest.com

 

[Greyhound247]

Hey Bricks,

What do you think about using the FT XL Power Pack to get this plane up in the air ? This power pack works great on my Scout XL. The Scout XL wing spam is 58 ". The kit has 17gram servos. Uses a 3300mAh battery. Maybe add a flight stabilizer can also help. Just throwing out some ideas.

FT XL Power Add-on

Complete your XL series RC plane with the FT XL Power Add-On. Includes servos, motor, ESC, and more for powerful, climb-ready flights.

store.flitetest.com

The wing span is the same. What about the weight?
As far as the servos, I'm fine getting the standard size (55g I believe) servos if I need to, but if the 17g servos with the kit will work thats even easier. Just want to make sure everything will play nicely together since I'm not an electronics expert (which is why I like the kits). Also as far as the receiver, I have the Spektrum AR620 and plan on getting another one for this plane as long as it is compatible with the ESC?

 

[alan0043]

The wing span is the same. What about the weight?
As far as the servos, I'm fine getting the standard size (55g I believe) servos if I need to, but if the 17g servos with the kit will work thats even easier. Just want to make sure everything will play nicely together since I'm not an electronics expert (which is why I like the kits). Also as far as the receiver, I have the Spektrum AR620 and plan on getting another one for this plane as long as it is compatible with the ESC?

Hey Greyhound,

The weight of my Scout XL with out the battery is 3lb 10oz. The Spektrum receiver should work with FT ESC.

 

[Bricks]

According to conversion tables to replace that Enya 19 will take 400-500 watts of power to fly the plane. Being I have no idea how the plane was built heavy, light I would weigh it then make the final decision of motor size. 17 gram servos should work as it is only a 3 channel plane rudder, elevator and motor.

 

[alan0043]

The following is some info on the motor from the kit. Sorry to say, that there is no info on the page talking about the watts on this motor.
I have a 12" prop on my Scout XL and things work out good for this plane.

FT 2814/1100KV Motor

Upgrade your RC plane with the FT 2814/1100KV Motor by Sunnysky. CNC-milled for weight reduction and enhanced heat dispersion. Ideal for FT Master Series Warbirds.

store.flitetest.com

 

[Bricks]

I would contact FT and ask what the watts or thrust is before I would purchase the motor, they do not give much information about it.

 

[Merv]

You need to figure out the all up weight (AUW) of the plane ready to fly. Weigh the airframe & all it's gear, then estimate the weight of the motor & battery to get the AUW.

The amount of thrust needed from the motor & prop depends on how you want to fly. A slow flying trainer, the thrust will need to be 60-80% of the weight of the plane. A typical plane, 80-100%. A war bird or one with a little zip will be 100-150%. A 3D plane will need 150-200% thrust to plane weight.

Watts per pound is another useful guideline. You'll need to weigh the plane and estimate the weight of the motor and battery.

• 50 to 70 watts per pound is the minimum level of power, good for park flyers and lightly loaded slow flyers.
•70 to 90 watts per pound is perfect for trainers and slow-flying aircraft.
•90 to 110 watts per pound is good for fast-flying scale models and some sport aerobatic aircraft.
•110 to 130 watts per pound is what you want for advanced aerobatics and high-speed aircraft.
•130 to 150 watts per pound is needed for lightly loaded 3D models and ducted fans.
•150 to 210+ watts per pound gives unlimited performance for any 3D model.

Here is a FT thread with more information.

Thrust vs Power to Weight Ratios for Prop Planes​

 

[alan0043]

Hi Everyone,

I came across this old FT video converting from gas to electric. There might be some helpful tips in the video. Enjoy.

 

[Greyhound247]

Thanks for the above info. The plane is 2.56 lbs currently so if my math is correct based on the above rough watts/pound I should be good with around 250 watts? I messaged FT about the watts for that motor so hopefully they get back to me. Otherwise, any recs for motor/esc/battery? Seems a bit complicated figuring out what all works together with the Kv and amps and how many cells/mah battery, which is why I like the kits. I have my pilots license so understand the physics of flight and assembly, but not an engineer/electrician so don't want the electronics to catch on fire...

 

[Merv]

... The plane is 2.56 lbs currently so if my math is correct based on the above rough watts/pound I should be good with around 250 watts?...

Is that the weight of the airframe alone or did you include the estimated weight of the motor & battery?

You need the weight of everything, the weight of the plane in the air.

 

[Greyhound247]

Is that the weight of the airframe alone or did you include the estimated weight of the motor & battery?

You need the weight of everything, the weight of the plane in the air.

Not entirely sure how to estimate that? since I don't know which motor/esc/battery.. sort of a catch 22. Also flite test doesn't put the weight of their kit stuff on their site.

 

[Shurik-1960]

The flight weight of your aircraft is equal to the weight of an aircraft with an old engine + the weight of fuel, determined by the volume of the tank. Knowing this weight gives you an idea of choosing an engine with the right thrust. The weight of the old motor and the fuel tank will give you the opportunity to pick up the battery by weight (subtract the weight of the electric motor).The number of cans is determined by the characteristics of the electric motor itself. It's time to take the plane into the sky.

 

[Greyhound247]

The flight weight of your aircraft is equal to the weight of an aircraft with an old engine + the weight of fuel, determined by the volume of the tank. Knowing this weight gives you an idea of choosing an engine with the right thrust. The weight of the old motor and the fuel tank will give you the opportunity to pick up the battery by weight (subtract the weight of the electric motor).The number of cans is determined by the characteristics of the electric motor itself. It's time to take the plane into the sky.

Thanks! That makes sense. The full weight with the old engine and full of fuel is 3.55 lbs. So sounds like I'll need about 350 watts. FT never messaged me back... might be off for the holiday or something. Anyone else know the watts of the power packs or have recs for a motor/ESC/battery that would work?

 

[Shurik-1960]

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This kit will enable your aircraft to walk through the sky on foot and perform classic aerobatics at high speed.

 

[alan0043]

Thanks! That makes sense. The full weight with the old engine and full of fuel is 3.55 lbs. So sounds like I'll need about 350 watts. FT never messaged me back... might be off for the holiday or something. Anyone else know the watts of the power packs or have recs for a motor/ESC/battery that would work?

Hi Greyhound,

Curious minds need to know. Have any luck with the conversion ?

 

[Greyhound247]

FT got back to me and said the 2814 motor should handle this plane.
New question:
I'm planning to re-cover the wing since it had some tears and I'm thinking of adding ailerons/flaps. Rather than using tissue/dope, I saw folks using Oracover which looked way simpler, so I may try that instead?
Regarding ailerons/flaps, I'm thinking of doing longer (4 spans) ailerons approx 1" wide and flaps (3 spans) near the center as drawn in the last picture. My concern is this trainer has a good amount of dihedral angle (2nd pic), so I'm concerned about how ailerons will perform. Thoughts?

 

[Shurik-1960]

The angle of inclination of the V-shaped wing is very large - there is an excellent option for the trainer model. Do not make ailerons - they will not work well.It is enough for you to control the rudder (keel). When you have the experience, you will be able to make a new foam wing without the wing angle + ailerons.With excellent engine thrust, the trainer will be able to make barrels.