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Nov 14, 2017, 06:28 PM
Sydney- Australia
asanga's Avatar
Discussion

Electric conversion of Nitro Trainer


Hi All

I have been given this 1.5m wing span balsa nitro trainer (bit like RCM trainer) by one my good friends . It has no engine but still got the fuel tank , fuel lines .,etc ,

The plane is about 20 years old and made from a balsa kit with covering. It has real metal hinges for all control surfaces and they seem to a be bit tight to move. I dont know the name of the plane either ....perhaps some one who had a similar model back then could help me with the name?

It has cut outs (40 x 20 x 36.5mm) for 3 big servos in the cockpit . The ailerons are controlled by one servo sits in the middle of the wing

I'm planing to convert it to an electric trainer and the current weight (as it is ) is wing= 384g, Fuse= 777g. Total =1161g
When I take the fuel tank , lines out the wight may go down by about 100-200g I think.

Also it uses wooden rods with metal ends as control rods and I'm thinking of changing them to either CF rods or 1.5mm piano wires. Is that a senibel thing to do ?

I'm paling on a 4S lipo (3000-4000 mah) power system with this motor https://hobbyking.com/en_us/turnigy-...or-1000kv.html

With a 60-70A ESC . Have separate 5A UBEC for the servos .

Since its a tricycle wheel setup the the maximum prop size I can use is 10 inch to have enough ground clearance .

Thinking of MG995 Metal Gear Servos (https://www.ebay.com.au/itm/4-PCS-MG...53.m1438.l2649)

I need 4 servos ( aileron, elevator, rudder and steerable nose wheel) . So the expected AUW is around 1600 -1800g

I'd like to know your thoughts & suggestions . So please feel free to comment, suggest

cheers
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Nov 14, 2017, 07:34 PM
Registered User
Looks like you got someone's cast off... a real mess there. You will need to replace the main landing gear with an aluminum one instead of the old worn out wire gear.
Remove covering and check for any damage or parts that have come unglued, that includes the fuse and the wings. You will need to clean up the fuel/oil residue from the fuse especially around the engine area.
You do not need to use metal geared servos. Standard servos will do just fine for that plane.
Once the covering is removed from the fuse you can then replace the old wooden pushrods and I suggest Sullivan nylon type as they are less expensive and easier to install. CF pushrods are not needed. You should also check the fuse for any broken, cracked or unglued parts.
You will probably need to replace the wheels as well.
You will need to remove the old fuel tank and replace it with a battery tray and modify the fuse for a hatch , usually just behind the firewall.
IF you do not have a radio buy one with a complete set of servos and receiver.
A 4S pack sounds right use at least 4000MAh. Do not mount the ESC inside the fuse. Mount it outside for air circulation.
Take into consideration how much clearance you have for a prop and then decide which motor you can use. You will probably have to use a somewhat high KV as those planes used a .40 size glow engine with a 10" 0r 11" prop.
You do not need a lot of power. Trainers usually need 50-75W/ Lb. or .5Kg You can go to 80 or 90 W/ .5 Kg just to get yourself out of trouble. You should need anything more than a 600 -700 watt motor, that way you can fly and remain with the 85% range of the motor /ESC and not stress either of the two .
Converting glow planes to electric takes some thought, especially one that is already built.
This is the place to go for answers. There are plenty of people who can help but if you can find someone near you, will be the best way.
Consider buying some extra balsa, some light weight plywood for the battery tray and some sort of hard wood sticks. to support the tray.
Check out this forum for more ideas.
Good luck.
Nov 14, 2017, 08:20 PM
Sydney- Australia
asanga's Avatar
Thanks for the advice & tips. I already have few radios , spektrum, turnigy and Frsky as I've been flying for over 18 months now.

cheers


Quote:
Originally Posted by jollyroger
Looks like you got someone's cast off... a real mess there. You will need to replace the main landing gear with an aluminum one instead of the old worn out wire gear.
Remove covering and check for any damage or parts that have come unglued, that includes the fuse and the wings. You will need to clean up the fuel/oil residue from the fuse especially around the engine area.
You do not need to use metal geared servos. Standard servos will do just fine for that plane.
Once the covering is removed from the fuse you can then replace the old wooden pushrods and I suggest Sullivan nylon type as they are less expensive and easier to install. CF pushrods are not needed. You should also check the fuse for any broken, cracked or unglued parts.
You will probably need to replace the wheels as well.
You will need to remove the old fuel tank and replace it with a battery tray and modify the fuse for a hatch , usually just behind the firewall.
IF you do not have a radio buy one with a complete set of servos and receiver.
A 4S pack sounds right use at least 4000MAh. Do not mount the ESC inside the fuse. Mount it outside for air circulation.
Take into consideration how much clearance you have for a prop and then decide which motor you can use. You will probably have to use a somewhat high KV as those planes used a .40 size glow engine with a 10" 0r 11" prop.
You do not need a lot of power. Trainers usually need 50-75W/ Lb. or .5Kg You can go to 80 or 90 W/ .5 Kg just to get yourself out of trouble. You should need anything more than a 600 -700 watt motor, that way you can fly and remain with the 85% range of the motor /ESC and not stress either of the two .
Converting glow planes to electric takes some thought, especially one that is already built.
This is the place to go for answers. There are plenty of people who can help but if you can find someone near you, will be the best way.
Consider buying some extra balsa, some light weight plywood for the battery tray and some sort of hard wood sticks. to support the tray.
Check out this forum for more ideas.
Good luck.
Nov 16, 2017, 08:39 AM
No bounce, No play.
davidmc36's Avatar
Nice to see a "Rescue" going on. Have done a few. You will learn a lot about building etc.
Nov 16, 2017, 10:19 AM
Registered User
Quote:
Originally Posted by davidmc36
Nice to see a "Rescue" going on. Have done a few. You will learn a lot about building etc.
And a lot about repairing.
I bought an old , well, not so old Ace Bingo air frame. Never finished. Had to resand the entire fuse, replace the tail feathers and finish sheeting the wings. Also lightened the fuse aft of the trailing edge and made a cowl for it. A lot of effort was put into the plane including changing it to dual aileron servos.
You never know what you are going to end up with someone else's cast off.
Nov 16, 2017, 02:12 PM
Sydney- Australia
asanga's Avatar
Quote:
Originally Posted by davidmc36
Nice to see a "Rescue" going on. Have done a few. You will learn a lot about building etc.
Yes , sure its going to be a lot of fun! I have built so many out of foam & foamcore not much with balsa so this will be a good project to improve my balsa skills
Nov 26, 2017, 07:11 PM
Sydney- Australia
asanga's Avatar
got some goodies for the conversion!
Nov 26, 2017, 08:03 PM
No bounce, No play.
davidmc36's Avatar
Nice spread of On-Board goodies ready for install. I like it more than seeing it finished.
Nov 27, 2017, 09:48 PM
Sydney- Australia
asanga's Avatar
Quote:
Originally Posted by davidmc36
Nice spread of On-Board goodies ready for install. I like it more than seeing it finished.
hopefully I'll get to finish it in the next few weeks !
Dec 05, 2017, 02:11 PM
Registered User
G Man's Avatar
Looks like an old OK Pilot QB 20H. These were good kits and made good flyers. They weren't overbuilt or too heavy. Some used light ply sides for the fuse. That made them a little heavier, but still light enough for decent conversion. Personally, I wouldn't go through the hassle of changing the gear. Wire gear works fine and by the time you change up the gear attach points for an aluminum gear, you haven't saved much weight and added a lot of work. Just put some lightweight wheels on it and move on.

As far as changing the pushrods, if they look okay, I'd leave them. But if you don't mind the added work, you might save a few grams changing them to carbon fiber.
Dec 05, 2017, 04:36 PM
No bounce, No play.
davidmc36's Avatar
Quote:
Originally Posted by G Man
....aluminum gear, you haven't saved much weight....
I guess it may depend on how large and thick the aluminum is to start with but I just actually saved quite a bit of weight on the Telemaster by switching to 5/32 wire landing gear.
Dec 12, 2017, 08:41 PM
Sydney- Australia
asanga's Avatar
Quote:
Originally Posted by G Man
Looks like an old OK Pilot QB 20H. These were good kits and made good flyers. They weren't overbuilt or too heavy. Some used light ply sides for the fuse. That made them a little heavier, but still light enough for decent conversion. Personally, I wouldn't go through the hassle of changing the gear. Wire gear works fine and by the time you change up the gear attach points for an aluminum gear, you haven't saved much weight and added a lot of work. Just put some lightweight wheels on it and move on.

As far as changing the pushrods, if they look okay, I'd leave them. But if you don't mind the added work, you might save a few grams changing them to carbon fiber.
cheers for the tips , yes this one appear to have thin ply sides . Wheels are heavy so like you said I might change the wheels to light ones and keep the wire landing gear for now .
Dec 12, 2017, 08:47 PM
Sydney- Australia
asanga's Avatar
did a static thrust test on the Turnigy D3548 / 1100kv motor and it produces about 2300g of thrust with 4S lipo and draws 47A of current. 1047 prop was used.

Turnigy D3548/4 1100KV Brushless Motor Thrust Test (4s lipo) (0 min 33 sec)
Dec 12, 2017, 08:51 PM
No bounce, No play.
davidmc36's Avatar
That blue box is one of the most valuable pieces of kit you can have
Dec 13, 2017, 07:44 AM
Registered User
I used light weight foam wheels on my Senorita and personally, I didn't like them. They allow too much bounce. Besides, there really isn't that much difference in weight and with the amount of power you have, you won't notice it.
I use Dubro treaded low bounce wheels. Very nice.


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