WW1 Biplane Scratch Build

[Hutch Bunch Rc]

This is my WW1 based biplane.

I used a few pictures of a Martin Mb1 bomber for reference.

I sadly don’t really have a whole lot of pictures of the build but here is what I have.

This is the early fuselage stage, basically a box with a rounded nose, the bottom of the nose opens up to a battery hatch for a 2200 3s.

The wings are relatively simple they are a flite test style and they each have a double foam spar with a 36” piece of 3/8 square spruce dowel. think the bottom wing is 52” and the top wing is 54”, the chord is 7”. The ailerons are only on the bottom wing.

Then I got the top wing all situated and the landing gear figured out, they curve around in a C shape and then glue onto some plywood.

Definitely needed this guy!

Last was the Nacelles, they were pretty easy, a box with a plywood firewall, the motor angles were pretty much a eyeball guess, everything on this plane was and eyeball guess really.

Here she is sitting next to my scratch built ugly stick.

Specs:

Top wingspan is 54”
Bottom wingspan is 52”
The chord is 7”
The fuselage length around 43”
Weight is around 2 1/2 pounds with the 2200 battery

Electronics: (Mostly bought off of value hobbies)

For motors I am using x2 flash hobbies 2830 1400kv motors, they each have over 700g of thrust and put out around 200 watts each, this is with a 3s and a 8x6 prop I think. This amount of power is enough, but the plane is very slow and sluggish.

https://www.flashhobby.com/index.php?id=3484

Esc:

I just used a few hobby king Skywalker 40a escs I had laying around, they are y’ed together for the receiver connection, one of the power leads is removed from one esc so there isn’t 2 BEC’s trying to power the receiver. Since there is only one battery, it is y’ed and goes off to each esc.

Battery:
I used a turnigy 2200 3s mainly because I have like 6 of them, and it’s also a common, cheap lipo size.

Receiver:

Any 6 channel receiver that works for you.

Servos:

x4 9g servos (2 for alerons, 1 for elevator, and 1 for the steerable tail wheel)

Maiden:

When I figure out how to add a video I will, but it flew great, only needed a few clicks of trim and it flew great. I think I can get 3-4 minute flights flying at full throttle most of the time.

(Edit) I figured out how to add the maiden video, here it is

 

[BATTLEAXE]

When does it fly?

 

[Hutch Bunch Rc]

When does it fly?

I’ve already flown it, it flys pretty good.

 

[Tench745]

I'd recommend switching to 9x4.5 props for a design like this. It's very draggy, but should have lots of lift, so the larger prop with less pitch should still get you flying speed but with more thrust to fight the drag.
It's also interesting that you chose to only put ailerons on the lower wing. It makes the most sense from a build standpoint, but most WWI aircraft I've seen have ailerons on the upper wing if they're not on both. Not really sure why that is.
If you decide you want a little more roll rate, cutting some ailerons into the upper wing would be pretty easy and the trailing edges can just tie to the lower ailerons with a pushrod so you don't have to add a servo.

If you have a video and can post it to Youtube, Facebook, Vimeo, or similar it's fairly easy to then post that video here. In the post toolbar click the three dots to the right of the emoji icon; the first one is "insert media" click that and paste the link to your video. Done.

 

[Hutch Bunch Rc]

I'd recommend switching to 9x4.5 props for a design like this. It's very draggy, but should have lots of lift, so the larger prop with less pitch should still get you flying speed but with more thrust to fight the drag.
It's also interesting that you chose to only put ailerons on the lower wing. It makes the most sense from a build standpoint, but most WWI aircraft I've seen have ailerons on the upper wing if they're not on both. Not really sure why that is.
If you decide you want a little more roll rate, cutting some ailerons into the upper wing would be pretty easy and the trailing edges can just tie to the lower ailerons with a pushrod so you don't have to add a servo.

If you have a video and can post it to Youtube, Facebook, Vimeo, or similar it's fairly easy to then post that video here. In the post toolbar click the three dots to the right of the emoji icon; the first one is "insert media" click that and paste the link to your video. Done.

Here is the maiden video on my yt channel

 

[Hutch Bunch Rc]

I'd recommend switching to 9x4.5 props for a design like this. It's very draggy, but should have lots of lift, so the larger prop with less pitch should still get you flying speed but with more thrust to fight the drag.
It's also interesting that you chose to only put ailerons on the lower wing. It makes the most sense from a build standpoint, but most WWI aircraft I've seen have ailerons on the upper wing if they're not on both. Not really sure why that is.
If you decide you want a little more roll rate, cutting some ailerons into the upper wing would be pretty easy and the trailing edges can just tie to the lower ailerons with a pushrod so you don't have to add a servo.

If you have a video and can post it to Youtube, Facebook, Vimeo, or similar it's fairly easy to then post that video here. In the post toolbar click the three dots to the right of the emoji icon; the first one is "insert media" click that and paste the link to your video. Done.

I will try the 9x4.5 props, you arnt talking about sf props right? Just a normal prop?

 

[Tench745]

I will try the 9x4.5 props, you arnt talking about sf props right? Just a normal prop?

I was just referring to props in general.
If you're running a regular 8x6, a regular 9x4.5 will draw about the same amperage. If you've been running an 8x6 SF you could run a 9x4.5 SF with nearly the same amp draw.
A Slow-Fly prop will draw a little more power than a regular prop but also produces more thrust.

The plane looks like it flies very nicely and predictably. Well done.

 

[Hutch Bunch Rc]

I was just referring to props in general.
If you're running a regular 8x6, a regular 9x4.5 will draw about the same amperage. If you've been running an 8x6 SF you could run a 9x4.5 SF with nearly the same amp draw.
A Slow-Fly prop will draw a little more power than a regular prop but also produces more thrust.

The plane looks like it flies very nicely and predictably. Well done.

I lied, I have a 7x4 prop on it, it’s a 1400kv 2826 motor, 205 watts, so what size 8” prop could I run for more thrust?

 

[Tench745]

I lied, I have a 7x4 prop on it, it’s a 1400kv 2826 motor, 205 watts, so what size 8” prop could I run for more thrust?

Running the numbers quickly through eCalc, it estimates your 7x4 prop on a 1400kv motor is drawing about 10 amps (per motor) and giving you about 20oz of thrust (per motor). With two motors you could almost fly vertically with your current setup.

For an 8" prop to draw about the same power as the 7x4 you'd need something like an 8x2.5 which I don't think anyone makes. The closest thing to that I can find is an 8x4 prop, which on that setup would draw a little over 13 amps (per motor) and give you around 24 oz of thrust (per motor). That would be about 4-5 minutes of flight time at full throttle, but I doubt you'd need full throttle except to pull a vertical climb.


For what it's worth, I had a Turnigy 2826 1400kv motor on my versa-spear wing and regularly ran either an 8x6 SF or a 9x4.5 SF. On my setup the motor drew about 19 amps with the 9x4.5 SF and theoretically put out 32oz of thrust. That's pushing at the top end of the motor specs, but the motor can handle a lot more prop than you have on it. However, you'd need more battery capacity to take advantage of it and I can't imagine your plane would like having that much power.

 

[Hutch Bunch Rc]

Running the numbers quickly through eCalc, it estimates your 7x4 prop on a 1400kv motor is drawing about 10 amps (per motor) and giving you about 20oz of thrust (per motor). With two motors you could almost fly vertically with your current setup.

For an 8" prop to draw about the same power as the 7x4 you'd need something like an 8x2.5 which I don't think anyone makes. The closest thing to that I can find is an 8x4 prop, which on that setup would draw a little over 13 amps (per motor) and give you around 24 oz of thrust (per motor). That would be about 4-5 minutes of flight time at full throttle, but I doubt you'd need full throttle except to pull a vertical climb.


For what it's worth, I had a Turnigy 2826 1400kv motor on my versa-spear wing and regularly ran either an 8x6 SF or a 9x4.5 SF. On my setup the motor drew about 19 amps with the 9x4.5 SF and theoretically put out 32oz of thrust. That's pushing at the top end of the motor specs, but the motor can handle a lot more prop than you have on it. However, you'd need more battery capacity to take advantage of it and I can't imagine your plane would like having that much power.

Those numbers can’t be accurate, there is no way I could do vertical on my current setup, maybe because of the high drag. At the current moment, and if you look in the maiden video, I am flying full throttle the whole time and it’s still that slow. I don’t really need more power, I think I’ll just add a rudder to help it turn better. Thanks for the help

 

[BATTLEAXE]

I lied, I have a 7x4 prop on it, it’s a 1400kv 2826 motor, 205 watts, so what size 8” prop could I run for more thrust?

A 9x4.5 would do that motor justice, however the 8x6 is still a worthy prop on that size of motor. It should stay under 30 amps with either. That plane at scale isnt a fast plane to begin with, so if you are into scale flying then the 9x4.5 would be what I would go with, especially on 3s. 8x6 isnt overkill but you are wasting energy on that high of pitch for the plane style. If you look at vids of the plane flying, or any WW1 bomber for that matter a lower pitch prop will be your best choice.

 

[Hutch Bunch Rc]

A 9x4.5 would do that motor justice, however the 8x6 is still a worthy prop on that size of motor. It should stay under 30 amps with either. That plane at scale isnt a fast plane to begin with, so if you are into scale flying then the 9x4.5 would be what I would go with, especially on 3s. 8x6 isnt overkill but you are wasting energy on that high of pitch for the plane style. If you look at vids of the plane flying, or any WW1 bomber for that matter a lower pitch prop will be your best choice.

Would the 9x4.5 give me a whole lot more thrust then the 7” prop that’s on it now? If not I’m not even going to bother doing it

 

[OliverW]

Would the 9x4.5 give me a whole lot more thrust then the 7” prop that’s on it now? If not I’m not even going to bother doing it

It'd give quite a bit more thrust!

 

[BATTLEAXE]

Would the 9x4.5 give me a whole lot more thrust then the 7” prop that’s on it now? If not I’m not even going to bother doing it

Yes but it is a twin so you do get double what you would normally think. The secret with props is that most of the thrust comes from the tips of the blades. the longer the prop the faster the tip speed hence the more thrust, in a sense. Depending on what you compare it to. If you are using 7 inch props now, no matter what the pitch is, you could gain up to 1/3rd more thrust on a 9 inch with less pitch.

I have cut down props by half an inch on either blade and have lost a noticeably considerable amount of thrust. Your motors can handle a 9x4.5, i have the same size of motors and stayed under 30 amps on the APC 9x4.5 MR props, (MR= multirotor). They usually come in a pack of 4 props, two CW and two CCW for drones, but they are ideal for electric fixed wing. They look just like Electric only props but are a bit more flexible then the electric only props, they stand up to more abuse. The pack is only usually around 10 bucks, and you get them in both directions so for a twin it is ideal. And there are two sets in the bag so you have a couple spares.

 

[Hutch Bunch Rc]

It'd give quite a bit more thrust!

Ok thanks oli

 

[Hutch Bunch Rc]

Yes but it is a twin so you do get double what you would normally think. The secret with props is that most of the thrust comes from the tips of the blades. the longer the prop the faster the tip speed hence the more thrust, in a sense. Depending on what you compare it to. If you are using 7 inch props now, no matter what the pitch is, you could gain up to 1/3rd more thrust on a 9 inch with less pitch.

I have cut down props by half an inch on either blade and have lost a noticeably considerable amount of thrust. Your motors can handle a 9x4.5, i have the same size of motors and stayed under 30 amps on the APC 9x4.5 MR props, (MR= multirotor). They usually come in a pack of 4 props, two CW and two CCW for drones, but they are ideal for electric fixed wing. They look just like Electric only props but are a bit more flexible then the electric only props, they stand up to more abuse. The pack is only ususally around 10 bucks, and you get them in both directions so for a twin it is ideal. And there are two sets in the bag so you have a couple spares.

Can you link your favorites? Thanks.

 

[BATTLEAXE]

Can you link your favorites? Thanks.

I buy them at the LHS, but any MR props are well suited for the task. The majority of my props are made for quads specifically

 

[Hutch Bunch Rc]

I buy them at the LHS, but any MR props are well suited for the task. The majority of my props are made for quads specifically

Ok thanks alot

 

[Hutch Bunch Rc]

Who thinks a bomb drop on this plane would be cool? I have a very simple idea in mind to have a door that swings down like the guinea pig, it might not work though because the bottom of the plane is flat.

 

[DinosEatPeople1]

Who thinks a bomb drop on this plane would be cool? I have a very simple idea in mind to have a door that swings down like the guinea pig, it might not work though because the bottom of the plane is flat.

Do a dauntless bomb swing sort of thing to be safe and it should be great!