Hello everyone,
I have a newbie question. I would like to convert a plane such as this: http://www.nitroplanes.com/df.html to electric. What do I need to take into consideration? I know I will need to build a motor mount and probably add some extra weight to the front to account for the lighter motor. Do you think I would have enough room to cram a 3000Mah lipo and esc?
If I did this I was thinking to use a 770kva motor at about 700 watts which in theory for this 4.5 pound plane should give me sufficient power. But, I'm not sure how to choose an appropriate prop.
Any assistance would be appreciated!

Thanks,
Brian

A 700 watt motor is less than about 1HP.

While that plane will fly in a very scale like manner with a .32-.40 glow engine ( in the same wattage range ) I would opt for at least an 800 watt or greater motor.

There is plenty of room to cram a PAIR of 3000mAh 14.8v LiPo packs in there or a single 5000mAh 14.8v pack... but it will be progressively harder to get over the 700 watt range with a single 14.8v pack. You may want to opt for a 6S setup instead using a motor in the 550kv range.

You have to remember that motor specs are OPTIMISTIC assessments of motor performance and if a motor is rated at 700 watts you'll probably see something more in the 600-650 range at best.

You can purchase a suitable motor mount, and the ESC will fit in the nose/cowl for best cooling.

However your biggest problem will be the lack of an access area to swap out the batteries while at the airfield.

There is no area on the bottom of the plane that would accept creating an access hatch.

From the top it MAY be doable, but you would have to be very careful.

You would also half to re-inforce the carbane area as you will be effectively weakening the area used to re-inforce the carbane and firewall.

Pretty bird.... Nice price too...

Almost makes me want to buy one.

I'll echo what has been said. The biggest challenge will be accessing the batteries.

Looking at the pictures, I'd probably cut a hatch that includes the canopy area, and extends forward to about the rear of the center support/cabanes. Leave the rear support of the canopy in place. Then the batteries go in, and slide forward.

See picture. I outlined (in red) about where I'd cut the hatch. The canopy would still go where it is. The back of the canopy would overlap the fuselage a little. A pin in the front of the hatch, and magnets in the back of the hatch.

The next challenge would be the ESC. I'd cut the cowl with a hole in the bottom for air to escape. I'd try to mount the ESC under the cowl along with the motor. That way, the two things you need cooling the most, are up there in the fresh air.

Good luck.

Hope you come back and report on the conversion..

I would agree with OPJose. It would be tough to get access to the battery because of the short nose. I do think that if the model used in the video flew on a 4 stroke Magnum 52, you might not need more than 700W, but that is not to say that 550W would be a good setup either.
Have fun and let us know how it works out.
Curtis

VMSGuy

I have several of these planes.

Putting the battery pack in that area is going to be problematic, in terms of getting the C.G. right, if not for the other reasons.

Usually you want the battery packs to sit in the space normally utilized for the fuel tank as this puts the weight in the right area.

The fuel tank is on the firewall.

I've thought of doing what he is thinking of, but stopped because the only available space is just behind the cowl.

With longer battery packs, it would then be difficult to slide them into place.

-

The plane itself is a great flyer, and I would like to electrify one of these as well.

Wow, I didn't even think about battery access issues. That makes sense since no one removes their empty gas tank to replace with a full one
I'm not yet sure if I want my first nice plane (I fly an aerobird swift now, ick) to be so heavily modified. I wish more of the nice nitro styles I see came in an electric flavor. I don't have anything against gas / nitro. I just want something clean and easy to maintain. But then at least with liquid fuel I won't have to charge a stack of batteries every night, except for the one used to control the electronics. *sigh* so many choices! :-D

Thanks for the excellent input guys!

Brian

Though it is out of stock at the moment, this is an excellent flyer....

[link=http://www.nitroplanes.com/blulflulbiar.html]Click me![/link]

It is smaller than the 40S, but it works great with a 480 sized motor and 11.1v batteries.

I get a lot of inquiries about mine when I bring it out to the field since it flies much like the larger plane.

Remember though with electrics you'll want to have multiple battery packs on hand.

There are several "standard" sizes that many planes will use...

e.g. 2200mAh 11.1v 3C batteries can be used as is for most 480 sized planes or there abouts.

Combine two of them with a simple "S" adaptor to create a 2200mAh 22.2v 6S pack for a larger .30-.40 sized electric... this does NOT destroy or modify the packs.

Combine two of them with a simple "P" adaptor to create a 4400mAh 11.1v 3S 11.1v pack for something like the SuperSportster EP ( I get 30 minutes of flight time on one set of packs!!! )

Combine Four of them with BOTH S and P adaptors to create a 4400mAh 22.2v 6S2P pack for a 90mm EDF Jet, etc.

Multiple uses out of one group of similiar packs.

This is why it pays to purchase matched sets of LiPo packs.

I did not say to put the batteries directly under the hatch. I think I said to make the hatch there, and then slide the batteries all the way forward.

"Then the batteries go in, and slide forward. "

In case you're interested...

http://www.hobbycity.com/hobbycity/s...h_Electric_ARF

Biplane. Ready to electrify.

I do not believe that will work, unless he removes the servo tray and switches things around a bit.

Not knowing the internal structure of the fuselage, you could be right. It all depends on what's located where. It might take major modification to electrify this bird.

I don't know if it's possible, but maybe the batteries could be put in between the cowl and the front of the center cabane/support. But only if the batteries could be "stood on end". The hatch would be smaller, the batteries would have to be appropriately sized... This'd be tough too.. But maybe.

Again.. You'd really have to have the plane physically in hand to look at before you could determine what's possible.

That plane looks awsome! I wish they weren't out of stock I have a ton of 2200MaH packs lying around as I fly helis as well so having a plane that works with those same packs is a huge plus!

This looks like an awsome kit and a very slick looking plane! I especially like the motor mount as I already have a 2550 ammo motor that would fit perfectly in there. Would a APC 6x4 prop work ok on this setup?

These are some very nice and affordable planes and they look awsome. Thanks for the links!

HobbyPeople have them in limited stock for only $5 more than NitroPlanes.
Curtis
P.S. That Hobbycity plane may cost you $50 to ship. No knock on HC, I love the site, but the shipping on ARFs adds up fast.

I think we may be getting a little worked up fast on this. If this is your second plane after the aerobird swift, you may want to rethink it. I am not that advanced, but from what i have gleaned here a bipe might be best as a third or more plane, not a good second. There are other planes like lower wingers that might be better for a second that you could use the same gear in and move to.
Just want to make sure it is a good investment and not a hasty mistake.
Curtis

Beau, you're right. Hobby city could be a bit spendy. But! If "you gotta have it, you gotta have it.. and money is no object!"

I've bought a couple things from them, small stuff, no ARFs. Only because that's the only source I could find.

I have enough plane kits and ARFs to keep me busy for a few years.

Good advice.

It's easy to focus on the original request, and loose sight of the bigger picture... I guess I'm guilty.

I didn't know biplanes were that much more advanced than other styles. I figured the increased lift area would allow lower speeds making it suitable for beginners. Should I be looking for a single under or over wing instead? I don't want anything too basic or slow. I would like to do at least simple aerobatics which my swift is way to underpowered to do.

Thanks,
Brian

There's a sticky, thread at the top of this forum, on what planes are available.

In it you will see "Intermediate" or "Second" planes. These are all possibilities. They'll be fun, and you can definitely do aerobatics you seek.

As for electrifying any of them. Personally, I'd stick to the ones with open engine compartments. Why? Easier to work with. Trust me on this. Fitting an electric motor and ESC to a plane with a cowl can be a hastle. Don't want to discourage you. And if you're bound and determined to do so, go ahead, have a blast.

Also, if you look around and do searches here, you may find people that have already electrified some of these aircraft, and can get you started with motor/ESC/battery configs from the get-go.

I'd probably stick with a .40 sized bird. Price for electrifying increases and an expanding rate as the size goes up. In other words it's not a linear escalation, closer to a exponential one.

Try to come to a "standard" battery setup. Pick a couple battery sizes, if you can, and stick to them. As stated earlier, you can gang and chain batteries together to come up with different setups. So if you stick to a few sizes/shapes/capacities... it'll pay off down the road.

Good luck, and let us know what you decide to do...

I would tend to agree with the rest, a Bipe might be a bit of a big step for a second plane. Of course, I don't know your actual skill level, so just speculation. I will say, my second plane was a 50" Edge 540. With the rates set to low, it's actually a very stable plane to fly. It made me a much better pilot. Also, as your skills progress, the rates can be adjusted to allow whatever flying you want to do.
There are multiple kits available that are already set up for electric, too. Mine was electric, it was a Stevens Aeromodel kit, not an ARF. It wass mostly Balsa, not ply, so it was super light. I flew mine with a Rimfire 1450kv 388 watt motor, with a 10x7 prop. I don't hover it or anything, so this setup was perfect. It was a very fast airplane, flew very crisp and accurate lines.

Bipes are a tad deceiving. This is from someone who may know the issues, but has yet to fly one himself, so take it with a grain of salt. The wingspans are shorter, even though there are two, the total wing area may add up to the total of a typical low wing plane. Here is the tough part. Because they are stacked, instead of one long wing, the plane has the ability to roll very easy, because the inertia is lower, and the wings act as levers, the longer they are, generally the more roll stability you have. Another thing is that because the wings are stacked, they are not as aerodynamically efficient as most low wing planes, so they tend to come in hot or tip stall easier. I would agree with the guys here, if you feel confident, get yourself a good low wing plane to move up into. It will give you confidence as you go and still be able to do aerobatics well. If you get a good glow engine or even a good brushless setup, that power thing will be a non-issue.
Have fun and good luck,
Curtis

I have many biplanes and fly them all the time.

Most RC model biplanes design around some of the potential problems.

The increased roll rate is not due to less inertia, but rather that you have more operating control surfaces. Normally the surface movement has to be toned down GREATLY to prevent over-responsiveness. Case in point the Ultimate the OP posted about needs only 4-5mm of aileron movement for HIGH RATES.

They are not inherently less efficient, quite the opposite, the biplane design was utilized to increase lift efficiency and structural strength for a given weight... the reason the Wright brothers never went with a Monoplane.

They sometimes seem to come in hotter, not because of inefficiencies, but rather the larger frontal cross section causes them to slow down VERY quickly when the throttle is chopped. In effect they are more draggy.

However certain designs such as the Skybolt, make the wings slightly wider to further increase lift, and let the plane decend far more slowly.

Often the characteristics of short tailed, short winged BiPlanes such as a Pitts, are used to describe general characteristics for all biplanes.
This is a mistake and is often repeated. A Pitts Biplane is designed for aerobatics and great snap roll behaviour. As such it has short wings and a short tail. You can apply Beau0090_99's observation to a Pitts Biplane.

However this is erroneous for say a Skybolt or a Stearman. Just try to drop a wing on either.

And then there are the high lift Biplanes like the Tiger Moth.... which you can land at a walk.